WO2021186769A1 - Power system monitoring device, power system monitoring method, and power system monitoring program - Google Patents

Power system monitoring device, power system monitoring method, and power system monitoring program Download PDF

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Publication number
WO2021186769A1
WO2021186769A1 PCT/JP2020/036455 JP2020036455W WO2021186769A1 WO 2021186769 A1 WO2021186769 A1 WO 2021186769A1 JP 2020036455 W JP2020036455 W JP 2020036455W WO 2021186769 A1 WO2021186769 A1 WO 2021186769A1
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Prior art keywords
power system
system monitoring
accident
monitoring device
phase
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PCT/JP2020/036455
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French (fr)
Japanese (ja)
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犬塚　達基
雅人 志賀
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株式会社日立製作所
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Publication of WO2021186769A1 publication Critical patent/WO2021186769A1/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/08—Locating faults in cables, transmission lines, or networks
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J13/00—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y04—INFORMATION OR COMMUNICATION TECHNOLOGIES HAVING AN IMPACT ON OTHER TECHNOLOGY AREAS
    • Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
    • Y04S10/00—Systems supporting electrical power generation, transmission or distribution
    • Y04S10/50—Systems or methods supporting the power network operation or management, involving a certain degree of interaction with the load-side end user applications
    • Y04S10/52—Outage or fault management, e.g. fault detection or location

Definitions

  • the present invention relates to a power system monitoring device for determining an accident point in a power system, a power system monitoring method, and a power system monitoring program.
  • the power system is a large-scale system constructed by combining many devices in order to provide a stable supply of electric power.
  • the electric power system it is known that the state changes due to various factors, and measuring devices for measuring physical quantities such as voltage, current, electric power, and frequency are used. Further, in order to realize a stable supply of energy, a control device combined with a measuring device is used.
  • Patent Document 1 provides a method for determining the occurrence of a ground fault using the phase relationship between voltage and current obtained as a sensor measurement signal.
  • Patent Document 1 calculates the phase difference between the zero-phase voltage and the zero-phase current from the measurement signal of the electric power system, and detects the occurrence of a ground fault by comparing it with a threshold prepared in advance. ..
  • a threshold prepared in advance.
  • the method of calculating the phase from the zero cross point between voltage and current has a problem that waveform distortion occurs at the time of an accident and noise such as line crosstalk is superimposed when the equipment is operated. Therefore, it is difficult to accurately detect the zero crossing point.
  • the threshold value for accident detection is high, accidents cannot be detected, and if it is too low, malfunctions due to noise increase.
  • the technique described in Patent Document 1 does not provide an appropriate method for setting a threshold value.
  • Patent Document 1 cannot detect an early event corresponding to such a sign.
  • the present invention has been made to solve the above problems, and an object of the present invention is to obtain a power system monitoring device, a power system monitoring method, and a power system monitoring program capable of detecting a sign of an accident.
  • the present invention is a power system monitoring device that detects an accident or a sign of an accident in a power system, and obtains a measurement signal obtained by measuring a voltage-current waveform (zero-phase current waveform, voltage-current waveform of each phase) of the power system.
  • a first means for example, measuring means
  • a second means for example, a similarity calculation means
  • a third means for example, a determination means for determining an electric phenomenon occurring in the power system is provided.
  • the threshold value of the phase difference for detecting an accident is not required. All of these contribute to the simplification of the device configuration and the improvement of the positioning accuracy. It enables the detection of accidents or signs of accidents from distorted current waveforms in a minute and short time.
  • FIG. 5 is a configuration diagram in which a power system monitoring device according to a fifth embodiment of the present invention is a base and aggregates measurement signals to detect signs. It is a flowchart explaining the operation of the power system monitoring apparatus which is 5th Embodiment of this invention. It is a flowchart explaining operation of a determination process. It is a figure which shows an example of the screen which the output part of the power system monitoring apparatus which is 5th Embodiment of this invention displays.
  • Case 1 An electrical phenomenon has occurred due to some accident factor, but the threshold value for accident detection has not been reached, and the operation is continued with the accident factor remaining. For example, in the case of a ground fault, a minute zero-phase current continues to flow due to a tree branch hanging from an electric wire or a defective insulation of equipment.
  • Case 2 After the accident is detected, the ground fault current becomes low for some reason and the cause of the accident is not identified, or the operation is restarted without removing the cause of the accident.
  • the events (electrical phenomena) related to these cases will be referred to as accident precursors.
  • the electrical phenomenon includes a ground fault, a disconnection, a disconnection, and the like, but in the present embodiment, a ground fault accident is assumed.
  • the cause of the accident is a ground fault
  • the sign may be paraphrased as a micro ground fault.
  • an accident and an accident sign are only distinguished by the performance of the detection device (for example, the threshold value of the protection relay) of the electrical phenomenon caused by the same factor.
  • the present embodiment provides a technique applicable to both an accident sign and an accident. As a result, if an accident sign that cannot be detected by a conventional protection relay can be detected, it will lead to prevention of subsequent accidents.
  • measuring devices are installed in the power system.
  • switches with sensors that can collect voltage and current waveforms
  • voltage regulators such as SVRs (Step Voltage Regulators)
  • sensors that make up protection relays in substations.
  • Sensors are also installed in devices such as distributed power sources and PCS (Power Conditioning System) that are connected to the grid.
  • PCS Power Conditioning System
  • the measurement signals of these power systems are used for detecting an accident or an accident sign.
  • FIG. 1 is an explanatory diagram illustrating a detection method in which the power system monitoring device according to the first embodiment of the present invention detects a ground fault.
  • the electric power system S1 is a three-phase electric power system in which a transformer 1 as a power source and a load 6 are connected by a transmission line.
  • the transmission line, the capacitance C L, is C R exists between the ground and each of the wires (lines).
  • another transformer 8 is connected in parallel with the transformer 1.
  • the transformer 1 has a star connection, and the neutral point is grounded.
  • a ground fault point P the accident point where a tree or the like comes into contact with an electric wire.
  • a zero-phase current I ⁇ 1 flows from the power supply side toward the ground fault point P
  • a zero-phase current I ⁇ 2 flows from the load side toward the ground fault point P. If the current is a positive value, a negative value) will flow.
  • the contact resistance at the accident point where a tree or the like comes into contact with an electric wire is indicated by RG.
  • the zero-phase currents I ⁇ 1 and I ⁇ 2 flowing toward the ground fault point P are vibration waveforms that swing positively and negatively, and that the waveform is distorted (harmonic components are generated).
  • the duration of the accident sign is not fixed in advance. Therefore, it is difficult to accurately measure the effective value and phase of the precursor waveform. In particular, it is difficult to accurately detect the zero cross point for measuring the phase. Therefore, in the present embodiment, although the instantaneous value (waveform) of the zero-phase current is measured, the electrical phenomenon of an accident or an accident sign is captured by analyzing the waveform (time-series signal) without detecting the zero cross point. do.
  • the power system monitoring device 100 utilizes the following properties of the zero-phase current measured as an instantaneous value when a microground fault (a sign of a ground fault) or a ground fault accident occurs. Perform waveform analysis.
  • Property 1 The zero-phase current flowing from the power supply side toward the ground fault point P and the zero-phase current flowing from the load side toward the ground fault point P flow through an electric circuit created by the same ground fault cause, so that the current flows.
  • the waveform is "similar”.
  • Property 2 The zero-phase current flowing from the power supply side toward the ground fault point P and the zero-phase current flowing from the load side toward the ground fault point P have opposite current signs because the flowing directions are opposite.
  • similarity is a relationship in which a plurality of figures are congruent by scale conversion (enlargement / reduction, shift, etc.).
  • the phase of the waveform position of the waveform in the time direction
  • the wave height amplitude of the waveform
  • the wave height and the phase are similar when the waveforms are scale-converted and the waveforms match.
  • the direction in which the current flows that is, the sign ( ⁇ ) of the current is inverted, means that the amplitude of the waveform is positive or negative inverted.
  • the zero-phase current at the time of an accident is a vibration waveform that swings positively and negatively, it is difficult to determine the inversion of the waveform from one instantaneous value.
  • the sign is determined using the correlation coefficient.
  • FIG. 2 is a configuration diagram of a ground fault determination using the correlation coefficient of the zero-phase currents at adjacent connection points.
  • the power system S1 includes a transformer 1 as a power source, a load 6, two switches 2 and 3 connected between the loads 6, and a power system monitoring device 100.
  • a ground fault has occurred between the two switches 2 and 3.
  • the switches 2 and 3 have a sensor function for electrically opening and closing and measuring zero-phase currents I ⁇ 1 and I ⁇ 2.
  • the power system monitoring device 100 includes a receiving means 10, a control unit 50, and an output unit 40.
  • the receiving means 10 receives the waveform signals (time series signal, measurement signal) of the zero-phase currents I ⁇ 1 and I ⁇ 2 measured at the two measurement points (switches 2 and 3), and is a volatile storage unit (register) (not shown). ).
  • the control unit 50 includes a correlation coefficient calculating means 25 as a similarity calculating means 20 and a ground fault determining means 31 as an electrical phenomenon determining means 30.
  • the output unit 40 displays the determination result that the ground fault determining means 31 has determined the ground fault or the ground fault sign. Further, the output unit 40 can also transmit the determination result that the ground fault determining means 31 has determined the ground fault or the sign of the ground fault to the external device.
  • An appropriate frequency filter means may be provided in order to remove unnecessary frequency components included in the measurement signal.
  • FIG. 3 is an explanatory diagram illustrating a calculation method for calculating the correlation coefficient of the zero-phase current.
  • the solid line is the zero-phase current I ⁇ 1 measured by the switch 2, and the broken line is the zero-phase current I ⁇ 2 measured by the switch 3.
  • the correlation coefficient calculating means 25 calculates the correlation coefficient of the zero-phase currents I ⁇ 1 and I ⁇ 2.
  • the correlation coefficient has a product-sum value (a value obtained by multiplying two signal values at the same time along the passage of time) in the numerator and a normalization coefficient in the denominator.
  • the correlation coefficient is obtained as a real value within the range of ⁇ 1 by dividing the numerator by the denominator. Further, when the correlation coefficient is 0, no correlation is shown, when it is larger than 0, it shows a positive correlation, and when it is less than 0, it shows a negative correlation.
  • FIG. 4 is a diagram showing a locus when two zero-phase currents are similar and inverted. If two zero-phase currents I ⁇ 1 and I ⁇ 2 are plotted in a two-dimensional space, a straight line is obtained. At this time, if the quadrant is determined by the combination of the signs of the two measurement signals and the signs of both are inverted, the locus exists in the second quadrant or the fourth quadrant. That is, if the loci of the two measurement signals draw a straight line in the second quadrant or the fourth quadrant, it can be seen that the waveform is inverted and similar. As a result, it is determined that there is a ground fault.
  • the correlation coefficient can be applied to the detection of a ground fault by utilizing the fact that the waveforms of the two zero-phase currents I ⁇ 1 and I ⁇ 2 are similar and the correlation coefficient is negative if the current flows in opposite directions. ..
  • the ground fault determining means 31 states that when the waveforms of the zero-phase currents I ⁇ 1 and I ⁇ 2 are similar and the waveforms are inverted, the ground fault point P (FIG. 1) exists between the two measurement points. judge. Since the absolute value of the correlation coefficient shows similarity, the condition that the waveform is similar and inverted is satisfied when the absolute value of the correlation coefficient is equal to or more than a predetermined value and a negative correlation coefficient is obtained. become. In other words, in the case of a negative correlation coefficient, the similarity is high when the absolute value of the correlation coefficient is large, and the similarity is low when the absolute value of the correlation coefficient is small.
  • the power system monitoring device 100 of the present embodiment uses the similarity (correlation coefficient) of a plurality of measurement signals (zero-phase currents I ⁇ 1, I ⁇ 2) of the power system to occur in the power system. Detects existing electrical phenomena (ground faults and signs of accidents). That is, in the power system monitoring device 100, the absolute value of the correlation coefficient of the waveforms of the zero-phase currents I ⁇ 1 and I ⁇ 2 flowing through the two measurement points (switches 2 and 3) is equal to or more than a predetermined value, and the sign of the correlation coefficient is When inverted, it is determined that the ground fault point P (FIG. 1) exists between the two measurement points. In other words, the power system monitoring device 100 determines that it is normal when the similarity is low, and determines that there is an accident sign when the similarity is high.
  • the waveform included in the zero-phase current is included in the current of any one phase of the three-phase alternating current. In many cases. Therefore, when it is determined that there is an accident sign, the similarity between the zero-phase current and each phase current is calculated, and it is determined that the phase with the highest similarity is the phase in which the ground fault occurs (ground fault phase). can do.
  • the interphase coefficient is used as the similarity, but the similarity is not limited thereto.
  • the following scales can be used. (1) Calculate the degree of matching (similarity) that the scale-converted waveforms match (2) After converting the waveform into frequency components, calculate the degree of matching (similarity) of the frequency components (3) Of the two waveforms Calculate the square error (4) Using the time shift amount (phase) and amplification factor (wave height) of the two waveforms as unknown variables, and the similarity between the two waveforms (for example, the square error) as a cost function, the condition that minimizes the cost is set.
  • the similarity is calculated by performing a numerical search (for example, optimum calculation by a particle group optimization method or the like).
  • a numerical search for example, optimum calculation by a particle group optimization method or the like.
  • the presence or absence of inversion of the sign of the waveform is also treated as a variable (that is, the similarity is calculated for both the positive and negative signs), and the sign with high similarity (either positive or negative) may be correct. ..
  • FIG. 5 is a configuration diagram showing a configuration of a power system monitoring device according to a second embodiment of the present invention. Similar to the first embodiment, the power system monitoring device 101 includes a receiving means 10, a similarity calculating means 20, and a ground fault determining means 31.
  • the receiving means 10 receives a measurement signal (time series signal) that measures the waveforms of the zero-phase currents I ⁇ 1 and I ⁇ 2, and stores the received measurement signal in the register 11.
  • the similarity calculation means 20 includes a scale conversion means 21, a similarity calculation means 22, a maximum similarity determination means 23, and a variable change means 24.
  • the scale conversion means 21 performs scale conversion of the wave height and the phase with respect to the waveform of one of the zero-phase currents I ⁇ 2, using the time shift amount (phase) and the amplification factor (wave height) as variables.
  • the similarity calculation means 22 calculates the similarity between the waveform of the other zero-phase current I ⁇ 1 and the scale-converted zero-phase current waveforms G and I ⁇ 2.
  • the similarity is obtained by the inner product, the cosine of the angle formed, the covariance, the correlation coefficient, the correlation function, and the like. That is, the similarity is not always standardized.
  • the maximum similarity determination means 23 outputs the maximum similarity among the similarity calculated by the similarity calculation means 22 while changing the variables of the scale conversion means 21. That is, the maximum similarity determination means 23 numerically searches for variables of wave height and phase.
  • the variable changing means 24 changes the variable of the scale conversion means 21 according to the instruction of the maximum similarity determining means 23. That is, when the similarity calculated by the similarity calculating means 22 is smaller than the similarity calculated in the past, the maximum similarity determining means 23 reduces the variable (wave height / phase) with respect to the variable changing means 24. Instruct. On the other hand, when the similarity calculated by the similarity calculating means 22 is larger than the similarity calculated in the past, the maximum similarity determining means 23 instructs the variable changing means 24 to increase the variables. As a result, the maximum similarity determination means 23 outputs the maximum similarity among the similarity calculated by the similarity calculation means 22.
  • the ground fault determining means 31 determines that the ground fault is a ground fault when the similarity calculated by the similarity calculating means 22 is the maximum and the signs of the correlation coefficients of the two zero-phase currents I ⁇ 1 and I ⁇ 2 are inverted.
  • the judgment is made using only the positive and negative signs of the correlation coefficient, and if the absolute value is unnecessary, the normalization of the correlation coefficient (dividing the numerator by the denominator) becomes unnecessary, and only the numerator can be calculated. good.
  • control unit 50 normalizes the wave height (for example, sets the maximum value of one wave height to 1.0) and removes the offset (for example, the short-term average value) as preprocessing of the measurement signal. You may do (set to 0.0) and so on.
  • the time width of the waveform (time series signal) for which the correlation coefficient is calculated is not limited, but can be calculated from a waveform having one cycle or less. On the other hand, the wider the time width, the less the influence of noise and the like, and stable results can be obtained.
  • a threshold value for determining the magnitude of the correlation coefficient may be used as a parameter.
  • a threshold value regarding the duration of the determination result can be prepared as a parameter, and it can be determined that a sign or an accident has been detected when the negative correlation continues for a certain period of time or longer. If there is a power supply, load, etc. on the line from the ground fault point to the measurement point, the similarity of the waveforms may decrease, so it is possible to determine the similarity by setting an appropriate margin as a parameter.
  • the present invention does not limit the parameters used for the determination.
  • a ground fault or an accident sign is detected, but a short circuit accident or an accident sign can also be detected.
  • FIG. 6 is an explanatory diagram illustrating a detection method in which the power system monitoring device according to the third embodiment of the present invention detects a short circuit accident.
  • the power system S2 includes a transformer 1 as a power source, a load 6, and switches 2 and 3 connected between the loads 6.
  • a transformer 1 as a power source
  • a load 6 a load
  • switches 2 and 3 connected between the loads 6.
  • a short-circuit accident an accident in which any two-phase electric wire or all three-phase electric wires come into contact to form an electric circuit through which currents ia and ib flow.
  • the short-circuited two-phase or three-phase lines are electrically connected, so that the phase potentials of the short-circuit phases are the same.
  • current inflow and outflow occur between the short-circuit phases.
  • the voltage and current of the three-phase AC When the power system S is in a normal state, the voltage and current of the three-phase AC have a phase shift of 120 degrees between each phase, but when a short-circuit accident occurs (common electricity at the short-circuit point).
  • the voltage and current of the short-circuit phase (because of having a circuit) include in-phase components.
  • the voltage and current of the three-phase alternating current include in-phase components. Even if these phenomena are judged using the magnitude and phase of the voltage vector, when the predictive waveform is minute and distorted, the error of the effective value or the phase becomes large, and the reliability of the judgment is inferior.
  • the electrical phenomenon caused by the short-circuit accident is determined by using the similarity of the measurement signals of each phase.
  • the three phases of the switches 2 and 3 are represented by a, b, and c, for example, the similarity of the waveform is calculated by the combination of the following phase voltages to determine the presence or absence of a short circuit. -Of the similarity between the phase a phase voltage and the phase voltage of the b phase, the similarity between the phase voltage of the b phase and the phase voltage of the c phase, and the similarity between the phase voltage of the c phase and the phase voltage of the a phase.
  • No pair is similar (no short circuit accident) -Of the similarity between the phase a phase voltage and the phase voltage of the b phase, the similarity between the phase voltage of the b phase and the phase voltage of the c phase, and the similarity between the phase voltage of the c phase and the phase voltage of the a phase.
  • There is a similarity in one set (there is a two-phase short circuit accident) -Of the similarity between the phase a phase voltage and the phase voltage of the b phase, the similarity between the phase voltage of the b phase and the phase voltage of the c phase, and the similarity between the phase voltage of the c phase and the phase voltage of the a phase.
  • the power system monitoring device determines that there is a short-circuit accident or a sign when the similarity of the phase voltages of at least two phases is high, and determines that there is no short-circuit accident or a sign of an accident when the similarity is low. This determination can be made using the above-mentioned calculation result of the correlation coefficient.
  • the power system monitoring device determines that there is a disconnection accident or a sign when the absolute value of the correlation coefficient of the phase voltage of at least two phases is equal to or more than the predetermined value, and the absolute value of the correlation coefficient is less than the predetermined value. At this time, it is judged that there is no short circuit accident or no sign of accident.
  • the similarity of the measurement signals of each phase is calculated by using a correlation coefficient or the like, and the aspect of the short circuit accident is determined by using the calculated similarity. Since the correlation coefficient is calculated using a waveform (time series signal) for a certain period, stable results can be obtained even for a minute and distorted waveform.
  • the period width and sampling period of the waveform (time series signal) are not limited, but it can be calculated from waveforms of one cycle or less. On the other hand, the wider the time width, the less the influence of noise, etc., and stable results are obtained. Be done.
  • FIG. 7 is an explanatory diagram illustrating a detection method in which the power system monitoring device according to the fourth embodiment of the present invention detects a disconnection accident.
  • the power system S3 includes a transformer 1 as a power source, a load 6, and switches 2 and 3 connected between the loads 6.
  • An accident in which at least one phase of the three-phase lines of the power system S3 is open is called a disconnection accident.
  • the electric wire is cut and hangs down.
  • the phase currents i ⁇ 1 and i ⁇ 2 that are disconnected at the disconnection point R do not flow.
  • the phase voltage on the power supply side and the phase voltage on the load side with the disconnection point R in between are not similar in measurement signals.
  • the electrical phenomenon caused by the above-mentioned disconnection accident is determined by using the similarity of the measurement signals.
  • the similarity of the phase voltage or phase current on the power supply side and the load side is calculated. -There is a similarity between the phase voltage on the power supply side and the phase voltage on the load side (no disconnection accident). -There is no similarity between the phase voltage on the power supply side and the phase voltage on the load side (there is a disconnection accident). -There is a similarity between the phase current on the power supply side and the phase current on the load side (no disconnection accident).
  • the power system monitoring device determines that there is a disconnection accident or a sign when the similarity of the phase voltages of at least two phases is low, and determines that there is no short-circuit accident or a sign of an accident when the similarity is high. This determination can be made using the above-mentioned calculation result of the correlation coefficient. That is, the power system monitoring device determines that there is a disconnection accident or a sign when the absolute value of the correlation coefficient of the phase voltage of at least two phases is less than the predetermined value, and the absolute value of the correlation coefficient is equal to or more than the predetermined value. At this time, it is judged that there is no short circuit accident or no sign of accident.
  • two measurement points are inserted between the transformer 1 as a power source and the load 6, and an accident or an accident sign occurs between them.
  • FIG. 8 is a configuration diagram in which the power system monitoring device according to the fifth embodiment of the present invention aggregates the measurement signals measured at a plurality of locations and detects a sign.
  • the power system S4 is configured by connecting a transformer 1 as a power source, a protection relay 7, a plurality of switches 2, 3, 4, 5 and a load 6 in series. Further, the power system S4 has a power system monitoring device 102 in which a plurality of switches 2, 3, 4, and 5 receive measurement waveforms obtained by measuring a three-phase voltage and a three-phase current.
  • the power system monitoring device 102 is installed at an aggregation base that aggregates information on the three-phase voltage and three-phase current of the power system S from a plurality of slave stations (switches 2, 3, 4, and 5).
  • the protection relay 7 is a switch that detects that a zero-phase current exceeding a predetermined value has flowed.
  • the switches 2, 3, 4, and 5 are switches that are opened and closed by a timed progressive system, and are provided with sensors that detect zero-phase current, phase voltage, and phase current.
  • the power system monitoring device 102 is a base server that receives waveform data such as zero-phase current waveforms measured by a plurality of switches 2, 3, 4, and 5 and voltage waveforms and current waveforms of each phase in time series. ..
  • the power system monitoring device 102 detects a ground fault and its sign by using the waveform data received from the adjacent switch.
  • the power system monitoring device 102 includes a control unit 50 and an output unit 40.
  • the control unit 50 detects ground fault accidents, short-circuit accidents, disconnection accidents, and signs thereof by using the voltage waveform, current waveform, and zero-phase current of each phase.
  • the output unit 40 displays the details of the accident such as the section where the accident or the sign of the accident occurred and the time when the accident occurred (see FIG. 11).
  • FIG. 9 is a flowchart for explaining the operation of the base server
  • FIG. 10 is a flowchart for explaining the operation of the determination process. These are flows when detecting a ground fault or a sign thereof by using the waveform of the received zero-phase current, but the same operation is performed when detecting a short-circuit accident or a disconnection accident.
  • the ground fault point P is between the adjacent switches 2 and 3.
  • the control unit 50 of the base server performs a sign detection determination process (S10) and displays the dissemination support information on the screen (S20). This screen display prevents accidents.
  • S10 the control unit 50 stores the received waveforms of the zero-phase currents of the plurality of switches 4, 2, 3, and 5 in the buffer memory (S1). After the storage, the control unit 50 calculates the correlation coefficient of the adjacent switches 4, 2, the switches 2, 3, and the switches 3, 5 (S2). After the processing of S2, the control unit 50 detects the sign of a ground fault (S3). Specifically, when the waveforms of the zero-phase currents flowing in the adjacent switches are similar and the waveforms are inverted, the control unit 50 determines that a ground fault has occurred between them. After the processing of S3, the control unit 50 outputs the determination result to the output unit 40 (S4).
  • the power system monitoring device 102 constantly receives the measurement signals of the plurality of switches 4, 2, 3, and 5, which increases the load on the data transmission line.
  • some kind of trigger may be prepared to start data transmission. For example, there is a method in which a threshold value is set in the switches 4, 2, 3 and 5 as slave stations, and data transmission is started when the measurement signal exceeds the threshold value.
  • a threshold value is set in the switches 4, 2, 3 and 5 as slave stations, and data transmission is started when the measurement signal exceeds the threshold value.
  • data transmission may be started for the reclosing section. Both have the effect of reducing the amount of data transmission compared to constant transmission.
  • the present invention does not limit these triggers for starting data transmission.
  • FIG. 11 is a diagram showing an example of a screen displayed by the output unit of the power system monitoring device according to the fifth embodiment of the present invention.
  • the display screen 200 is a screen displayed by the output unit 40, and includes texts and graphs indicating how to deal with the accident and recovery support information when an accident in the power system or a sign thereof is detected.
  • the accident content 210 including the accident occurrence time 211, the accident occurrence section 212, and the accident occurrence probability 213, and the restoration support information 220 consisting of the restoration procedure 221 and the necessary supplies 222 at the time of restoration, the past case 223, and the like are displayed. Is displayed in text.
  • the recovery support information 220 can be prepared by creating a database of past accidents and countermeasures and searching the database based on the detection results of accidents or signs.
  • the accident occurrence time 211 is the time when the accident or the accident sign occurred. It is displayed that the accident occurrence section 212 is any of the adjacent switches 4 and 2, between the switches 2 and 3, and between the switches 3 and 5.
  • the restoration procedure 221 differs depending on whether it is a ground fault accident, a short circuit accident, or a disconnection accident, and is displayed as, for example, "Refer to Manual Z".
  • the equipment 222 also differs depending on the ground fault accident, the short circuit accident, the disconnection accident, and the accident occurrence section 212.
  • the recovery support information 220 may be combined with different accident response technologies. For example, the results of the accident section detection technique and the accident point determination technique may be combined and used for screen display or database search. Furthermore, if accident cause estimation technology or the like is available, it can be combined with the above.
  • the accident occurrence probability 213 is displayed, for example, by regarding the absolute value of the correlation coefficient as the probability of a ground fault, or by multiplying the absolute value of the correlation coefficient by a predetermined conversion formula as the probability of a ground fault. do.
  • the correlation coefficient is a real number that falls within the range of ⁇ 1, although it is a different measure from the probability. Further, the larger the absolute value of the correlation coefficient, the more similar the two waveforms are. Therefore, the absolute value of the correlation coefficient may be regarded as the probability of a ground fault. When the correlation coefficient is 0, the probability of a ground fault is 0, and when the absolute value of the correlation function is 1, it can be regarded as a complete ground fault (probability of a ground fault is 1).
  • the base server that aggregates the zero-phase current, phase voltage, and phase current measured by each of the slave stations (switches 4, 2, 3, and 5) determines an accident or an accident sign.
  • each slave station of the switch 4, 2, 3, and 5 may determine an accident or an accident sign.
  • FIG. 12 is a configuration diagram in which the power system monitoring device according to the sixth embodiment of the present invention detects a sign as a slave station.
  • the power system S5 is configured by connecting a transformer 1 as a power source, a protection relay 7, a plurality of switches 2, 3, 4, 5 and a load 6 in series. ing. Further, the power system S5 measures the zero-phase current, the voltage waveform of each phase, and the current waveform of each phase in its own device (for example, the switch 3 on the load side of the ground fault point P), and also another switch. It has a slave station (power system monitoring device 103) that receives waveform data measured by 2, 4 and 5 and performs accident determination and predictive determination.
  • the power system monitoring device 103 of the switch 3 determines a ground fault or a sign based on the waveform data of the zero-phase current measured by its own device and the waveform data of the zero-phase currents of the adjacent switches 2 and 5. conduct.
  • the ground fault point P is between the switches 2 and 3
  • the absolute correlation coefficient between the zero-phase current waveform data measured by the own device and the zero-phase current waveform data of the adjacent switch 2 is absolute. The value increases.
  • the power system S5 includes a base server 104 that aggregates information (determination results) from a plurality of distributed power system monitoring devices 103.
  • each of the plurality of power system monitoring devices 103 has an output unit 40 and a control unit 50, as in the power system monitoring device 102 (FIG. 8) of the fifth embodiment.
  • FIG. 13 is a flowchart illustrating the operation of the power system monitoring device according to the sixth embodiment of the present invention.
  • any one of the plurality of power system monitoring devices 103 may start the process, and the base server 104 may instruct the start of the process. That is, this flow does not limit the trigger for starting processing.
  • the control unit 50 of the power system monitoring device 103 determines whether or not an accident or an accident sign has been detected, as in the fifth embodiment (S10). However, in the buffer memory storage (S1) in this determination process (S10, FIG. 10), the zero-phase current, phase voltage, and phase current measured by the own device and the zero-phase current and phase voltage measured by the adjacent switch are used. , Both the phase current and the phase current are stored in the buffer memory. Further, also in the result output (S4), the output unit 40 displays the display screen 200 (FIG. 11) of the fifth embodiment. For example, in the accident occurrence section 212, the power supply side or the load side is indicated with respect to the own device.
  • the control unit 50 After the processing of S10, the control unit 50 notifies the base server 104 of the determination result. As a result, the base server 104 receives the zero-phase current, the phase voltage, and the phase current measured by the plurality of switches 4, 2, 3, and 5 and the determination result determined by the plurality of power system monitoring devices 103. As a result, accidents can be prevented.
  • This embodiment does not limit the method of configuring the communication path with the power system monitoring device 103 as a neighboring slave station.
  • communication via a power line communication via a communication path different from the power line (for example, optical fiber, etc.), communication via some wireless communication path, and the like can be used.
  • the procedure for starting and ending data transmission via the communication path is not limited.
  • There are a method of constantly transmitting the measured data a method of transmitting data when a certain threshold is exceeded, a method of transmitting data in response to a request, and the like.
  • the method of detecting an accident or a sign by using the communication function between slave stations has an effect of reducing the load of data transmission and data processing.
  • the power system monitoring device of the first to fourth embodiments has determined any accident or accident sign of a ground fault, a short circuit, or a disconnection, but has determined all of the ground fault, the short circuit, and the disconnection. It doesn't matter.
  • FIG. 14 is a configuration diagram of a power system monitoring device according to a seventh embodiment of the present invention.
  • the power system monitoring device 105 includes a receiving means 10, a control unit 50, and an output unit 40, and the control unit 50 includes a ground fault sign determining means 51, a short circuit accident sign determining means 52, and a disconnection accident sign determining means 53. To be equipped.
  • the receiving means 10 receives the waveform signals of the zero-phase current, the phase voltage, and the phase current detected by the plurality of switches 2, 3, 4, and 5, and stores them in the register 11.
  • the ground fault sign determining means 51 includes, for example, the correlation coefficient calculating means 25 and the ground fault determining means 31 of the first embodiment (FIG. 2).
  • the ground fault sign determination means 51 calculates the correlation coefficient of the adjacent switches 2, 3, 4, and 5 stored in the register 11, the absolute value of the correlation coefficient is larger than the predetermined value, and the sign is inverted. When it is, it is judged as a ground fault accident or an accident sign.
  • the short-circuit accident sign determination means 52 determines that there is a short-circuit accident or a sign thereof when the similarity of the phase voltages of at least two phases among the phase voltages of each phase stored in the register 11 is high.
  • the disconnection accident sign determination means 53 determines that there is a disconnection accident or a precursor when the similarity to the phase voltage or phase current of each phase of the adjacent switches 2, 3, 4, and 5 is low.
  • the output unit 40 displays the accident content or via a network. And output.
  • the present invention is not limited to the above-described embodiment, and various modifications such as the following are possible.
  • the output unit 40 of the power system monitoring device 102 of the fifth embodiment displays the accident occurrence probability 213 on the display screen 200 (FIG. 11).
  • the control unit 50 regards the absolute value of the correlation coefficient as the accident probability, or the value obtained by multiplying the absolute value of the correlation coefficient by a predetermined conversion formula as the accident probability.
  • the control unit 50 of the present embodiment obtains a determination result by combining the measurement signal and external conditions such as the system configuration related to the power system, past accident history, weather conditions, and tree growth. For example, a calculation using a probability can be used to combine a plurality of factors and quantify them as a compound factor. For probability calculation, the concept of Bayesian probability (Bayesian statistics) can be used. For example, by preparing prior probabilities and normalizing them by multiplying them by probability values indicating the likelihood of accident factors, posterior probabilities that combine multiple factors are calculated.
  • Bayesian statistics Bayesian statistics
  • the control unit 50 sets the probability obtained by conversion in this way as a prior probability. Then, the control unit 50 sets an external situation related to electric power as a conditional probability, and calculates the posterior probability using the Bayesian formula. The probability is updated by repeating the procedure of calculating the posterior probability from the prior probability using the probability based on multiple conditions and the probability with the passage of time.
  • the correlation coefficient is used as a scale for measuring the similarity between the two waveforms, but a square error or the like can also be used.
  • the square error is a real value calculated by squaring the difference between two signals and accumulating over a certain interval, and takes the minimum value when the waveforms are similar.
  • the correlation coefficient and squared error have the same properties as the integral calculation because the cumulative calculation is performed over a certain time width, and they are not easily affected by noise, and stable calculation results can be obtained even for minute signals. There are features that can be obtained.
  • the square error of two measurement signals is used as a measure of similarity, the square error is a positive real value and does not reflect the inversion of the waveform. Therefore, when determining the inversion of the waveform, for example, as described with reference to FIG. 4, it is necessary to use the sign of the correlation coefficient.
  • the similarity may be calculated after performing some kind of signal conversion (for example, Fourier transform for converting into a frequency component or the like). For example, using the Fourier transform, two measurement signals (time series signals) are converted into frequency components, and the frequency components of both are compared. Then, the difference of the frequency component for each order of the harmonic is calculated as the squared error. Again, since the squared error is a positive real value, it does not reflect the inversion of the waveform. Therefore, for example, as described with reference to FIG. 4, the code of the correlation coefficient is used.
  • some kind of signal conversion for example, Fourier transform for converting into a frequency component or the like.
  • Fourier transform for example, two measurement signals (time series signals) are converted into frequency components, and the frequency components of both are compared. Then, the difference of the frequency component for each order of the harmonic is calculated as the squared error.
  • the squared error is a positive real value, it does not reflect the inversion of the waveform. Therefore, for example, as described with reference to FIG. 4,

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  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
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Abstract

A power system monitoring device 100 for detecting an accident or a sign of an accident of a power system S1 is provided with: a reception means 10 for receiving measurement signals obtained by measuring voltage current waveforms Iα1, Iα2 of the power system S1 from a plurality of measurement points; a correlation coefficient calculation means 20 for calculating a similarity between the voltage current waveforms Iα1, Iα2; and a ground fault determination means 30 for determining, by using the similarity, a ground fault sign or a ground fault accident occurring in the power system S1. The ground fault determination means 30 determines either one of a normal state and a sign of an accident on the basis of the level of the similarity.

Description

電力系統監視装置、電力系統監視方法、及び電力系統監視プログラムPower system monitoring device, power system monitoring method, and power system monitoring program
　本発明は、電力系統における事故点を標定する電力系統監視装置、電力系統監視方法、及び電力系統監視プログラムに関する。 The present invention relates to a power system monitoring device for determining an accident point in a power system, a power system monitoring method, and a power system monitoring program.
　電力系統は、電力を安定供給するために、多くの機器を組み合わして構築されている大規模システムである。電力系統では、状態が様々な要因で変化することが知られており、電圧、電流、電力、周波数等の物理量の計測を行う計測機器が使用されている。また、エネルギーの安定供給を実現するため、計測機器と組み合わせた制御機器が使用されている。 The power system is a large-scale system constructed by combining many devices in order to provide a stable supply of electric power. In the electric power system, it is known that the state changes due to various factors, and measuring devices for measuring physical quantities such as voltage, current, electric power, and frequency are used. Further, in order to realize a stable supply of energy, a control device combined with a measuring device is used.
　電力供給に支障をもたらす事故が発生したときに、電力会社は、速やかに事故内容（事故原因や事故箇所）を特定して復旧作業を開始する必要がある。このことは、供給信頼度を高めるために必須の要請となっている。事故内容を速やかに把握するため、電力系統では、変電所や開閉器等にリレーや検出器等を設置し、電圧ベクトルや電圧と電流との位相、等を用いて事故検出が行われている。 When an accident that interferes with the power supply occurs, the electric power company needs to promptly identify the content of the accident (cause of the accident and the location of the accident) and start the restoration work. This is an essential requirement for increasing supply reliability. In order to quickly grasp the details of an accident, relays and detectors are installed in substations and switches in the power system, and accident detection is performed using the voltage vector and the phase between voltage and current. ..
　しかしながら、事故内容の詳細を把握するには、事故が発生した現場に人を派遣して、人による確認作業によって事故原因と事故箇所とを特定することが不可欠である。担当者が現場へ到着してから事故内容を特定するため、作業時間が掛かり、また担当者の経験、知識、体調などの個人的な能力が問題になる。 However, in order to grasp the details of the accident, it is indispensable to dispatch a person to the site where the accident occurred and identify the cause of the accident and the location of the accident by confirmation work by the person. Since the person in charge identifies the accident content after arriving at the site, it takes time to work, and the person in charge's personal ability such as experience, knowledge, and physical condition becomes a problem.
　一方、電力系統に各種センサを設置して、センサ計測信号を用いて系統状態を推定したり、事故の有無や事故内容を推定したりする方法が提案されている。これらの推定技術として、例えば、近年になって進展が著しいネットワークとデジタル信号処理技術とを組み合わせる方法がある。 On the other hand, a method has been proposed in which various sensors are installed in the power system and the system state is estimated using sensor measurement signals, and the presence or absence of an accident and the content of the accident are estimated. As these estimation technologies, for example, there is a method of combining a network and a digital signal processing technology, which have made remarkable progress in recent years.
　特許文献１は、センサ計測信号として得られる電圧と電流の位相関係を用いて地絡事故の発生を判定する方法を提供している。 Patent Document 1 provides a method for determining the occurrence of a ground fault using the phase relationship between voltage and current obtained as a sensor measurement signal.
特開２０１４－１４２０８号公報Japanese Unexamined Patent Publication No. 2014-14208
　特許文献１に記載の技術は、電力系統の計測信号から零相電圧と零相電流との位相差を算出して、事前に用意した閾値と比較して地絡事故の発生を検出している。しかしながら、実用化には、計測信号から電圧と電流との位相を精度よく検出することは困難であるという課題がある。例えば、電圧と電流とのゼロクロス点から位相を算出する方法は、事故時に波形歪みが生じ、また、機器の動作時に線間クロストーク等のノイズが重畳する問題点がある。このため、ゼロクロス点を精度良く検出することは困難である。さらに、事故検出の閾値は、高ければ事故を検出できず、低すぎればノイズによる誤動作が多くなる。特許文献１に記載の技術には、閾値の適切な設定方法は用意されていない。 The technique described in Patent Document 1 calculates the phase difference between the zero-phase voltage and the zero-phase current from the measurement signal of the electric power system, and detects the occurrence of a ground fault by comparing it with a threshold prepared in advance. .. However, for practical use, there is a problem that it is difficult to accurately detect the phase of voltage and current from the measurement signal. For example, the method of calculating the phase from the zero cross point between voltage and current has a problem that waveform distortion occurs at the time of an accident and noise such as line crosstalk is superimposed when the equipment is operated. Therefore, it is difficult to accurately detect the zero crossing point. Further, if the threshold value for accident detection is high, accidents cannot be detected, and if it is too low, malfunctions due to noise increase. The technique described in Patent Document 1 does not provide an appropriate method for setting a threshold value.
　また、電力系統に起きる事象は、樹木の一端が電線に触れるような予兆の段階から、徐々に密な接触になり事故に至るような場合がある。特許文献１の技術では、このような予兆に相当する初期の事象を検出することができない。 In addition, the event that occurs in the electric power system may lead to an accident from the stage of a sign that one end of the tree touches the electric wire, gradually becoming a close contact. The technique of Patent Document 1 cannot detect an early event corresponding to such a sign.
　本発明は、前記課題を解決するためになされたものであり、事故の予兆を検出することができる電力系統監視装置、電力系統監視方法、及び電力系統監視プログラムを得ることを目的とする。 The present invention has been made to solve the above problems, and an object of the present invention is to obtain a power system monitoring device, a power system monitoring method, and a power system monitoring program capable of detecting a sign of an accident.
　本発明は、電力系統の事故又は事故予兆を検出する電力系統監視装置であって、前記電力系統の電圧電流波形（零相電流の波形、各相の電圧電流波形）を計測した計測信号を、複数の計測点から受信する第１の手段（例えば、計測手段）と、複数の前記電圧電流波形の相似性を算出する第２の手段（例えば、相似性計算手段）と、前記相似性を用いて、前記電力系統で発生している電気現象を判定する第３の手段（例えば、判定手段）と、を備えることを特徴とする。 The present invention is a power system monitoring device that detects an accident or a sign of an accident in a power system, and obtains a measurement signal obtained by measuring a voltage-current waveform (zero-phase current waveform, voltage-current waveform of each phase) of the power system. Using the first means (for example, measuring means) receiving from a plurality of measurement points, a second means (for example, a similarity calculation means) for calculating the similarity of the plurality of voltage / current waveforms, and the similarity. A third means (for example, a determination means) for determining an electric phenomenon occurring in the power system is provided.
　計測波形の相似性を利用し、電圧と電流との位相差を利用しない。また、事故検出するための位相差の閾値を必要としない。これらは、何れも装置構成の簡易化と標定精度の向上に寄与する。微小・短時間で歪みのある電流波形から事故又は事故予兆の検出を可能とする。 Use the similarity of measured waveforms and do not use the phase difference between voltage and current. Moreover, the threshold value of the phase difference for detecting an accident is not required. All of these contribute to the simplification of the device configuration and the improvement of the positioning accuracy. It enables the detection of accidents or signs of accidents from distorted current waveforms in a minute and short time.
　本発明によれば、事故の予兆を検出することができる。 According to the present invention, it is possible to detect a sign of an accident.
本発明の第１実施形態である電力系統監視装置が地絡事故を検出する検出方法を説明する説明図である。It is explanatory drawing explaining the detection method which detects the ground fault accident by the electric power system monitoring apparatus which is 1st Embodiment of this invention. 本発明の第１実施形態である電力系統監視装置が隣接する接続点での零相電流の相関係数を用いた地絡事故判定の構成図である。It is a block diagram of the ground fault determination using the correlation coefficient of the zero-phase current at the connection point where the power system monitoring device which is 1st Embodiment of this invention is adjacent. 零相電流の相関係数を算出する算出方法を説明する説明図である。It is explanatory drawing explaining the calculation method which calculates the correlation coefficient of a zero-phase current. ２つの零相電流が相似かつ反転しているときの軌跡を示す図である。It is a figure which shows the locus when two zero-phase currents are similar and inverted. 本発明の第２実施形態である電力系統監視装置の構成を示す構成図である。It is a block diagram which shows the structure of the electric power system monitoring apparatus which is 2nd Embodiment of this invention. 本発明の第３実施形態である電力系統監視装置が短絡事故を検出する検出方法を説明する説明図である。It is explanatory drawing explaining the detection method which detects the short circuit accident by the power system monitoring apparatus which is 3rd Embodiment of this invention. 本発明の第４実施形態である電力系統監視装置が断線事故を検出する検出方法を説明する説明図である。It is explanatory drawing explaining the detection method which detects the disconnection accident by the power system monitoring apparatus which is 4th Embodiment of this invention. 本発明の第５実施形態である電力系統監視装置が拠点で、計測信号を集約して予兆検出する構成図である。FIG. 5 is a configuration diagram in which a power system monitoring device according to a fifth embodiment of the present invention is a base and aggregates measurement signals to detect signs. 本発明の第５実施形態である電力系統監視装置の動作を説明するフローチャートである。It is a flowchart explaining the operation of the power system monitoring apparatus which is 5th Embodiment of this invention. 判定処理の動作を説明するフローチャートである。It is a flowchart explaining operation of a determination process. 本発明の第５実施形態である電力系統監視装置の出力部が表示する画面の一例を示す図である。It is a figure which shows an example of the screen which the output part of the power system monitoring apparatus which is 5th Embodiment of this invention displays. 本発明の第６実施形態である電力系統監視装置が計測する子局で予兆検出する構成図である。It is a block diagram which the predictive detection is detected by the slave station measured by the power system monitoring apparatus which is 6th Embodiment of this invention. 本発明の第６実施形態である電力系統監視装置の動作を説明するフローチャートである。It is a flowchart explaining the operation of the power system monitoring apparatus which is 6th Embodiment of this invention. 本発明の第７実施形態である電力系統監視装置の構成図である。It is a block diagram of the power system monitoring apparatus which is 7th Embodiment of this invention.
　以下、図面等を用いて、本発明の実施形態について説明する。以下の実施形態は、本願発明の内容の具体例を示すものであり、本願発明がこれらの実施例に限定されるものではなく、本明細書に開示される技術的思想の範囲内において当業者による様々な変更および修正が可能である。 Hereinafter, embodiments of the present invention will be described with reference to drawings and the like. The following embodiments show specific examples of the contents of the present invention, and the present invention is not limited to these examples, and those skilled in the art are skilled in the art within the scope of the technical idea disclosed in the present specification. Various changes and modifications can be made by.
（電力系統の事故監視について）
　電力系統の技術は、一般に、配電系統と送電系統とに分けて説明される。以下の実施形態では、配電系統に着目して説明するが、本発明は、送電系統にも適用可能な技術である。電力系統には、地絡、短絡、断線と呼ばれる事故が発生することがある。これらの事故が発生したときの対処としては、まず変電所に備わっている保護リレーが所定値以上の地絡電流を検知する。この事故検知により、時限順送方式によって、開閉器を操作して事故区間を特定していく。 (About power system accident monitoring)
Power system technology is generally described separately for distribution and transmission systems. In the following embodiments, the distribution system will be focused on, but the present invention is a technique applicable to the power transmission system. Accidents called ground faults, short circuits, and disconnections can occur in the power system. As a countermeasure when these accidents occur, the protection relay installed in the substation first detects a ground fault current of a predetermined value or more. Based on this accident detection, the switch is operated by the timed progressive method to identify the accident section.
　しかしながら、この手順では対応できない事例がある。例えば、
　事例１：何らかの事故要因による電気現象が起きているが事故検出の閾値に至らず、事故要因が残ったまま運用を継続する場合である。例えば、地絡事故の場合、電線に木の枝が垂れ下がったり、設備の絶縁不良があったりして、微小な零相電流が流れ続けている場合である。
　事例２：事故検出したあとで、何らかの理由で地絡電流が低くなり、事故要因が特定されない場合や、事故原因が除去されない状態で運用を再開する場合である。 However, there are cases where this procedure cannot be used. for example,
Case 1: An electrical phenomenon has occurred due to some accident factor, but the threshold value for accident detection has not been reached, and the operation is continued with the accident factor remaining. For example, in the case of a ground fault, a minute zero-phase current continues to flow due to a tree branch hanging from an electric wire or a defective insulation of equipment.
Case 2: After the accident is detected, the ground fault current becomes low for some reason and the cause of the accident is not identified, or the operation is restarted without removing the cause of the accident.
　これらの事例は、何れも事故要因があるにも関わらず、従来技術（例えば、変電所の保護リレー）では事故として検出することができない。以下、これらの事例に関わる事象（電気現象）を事故予兆と呼ぶことにする。ここで、電気現象には、地絡、断線、切断等があるが、本実施形態では、地絡事故を想定している。また、事故原因が地絡であるとき、予兆を微地絡と言い換える場合がある。 Although all of these cases have accident factors, they cannot be detected as accidents by conventional technology (for example, protection relays of substations). Hereinafter, the events (electrical phenomena) related to these cases will be referred to as accident precursors. Here, the electrical phenomenon includes a ground fault, a disconnection, a disconnection, and the like, but in the present embodiment, a ground fault accident is assumed. In addition, when the cause of the accident is a ground fault, the sign may be paraphrased as a micro ground fault.
　事故と事故予兆とは、同じ要因によって引き起こされている電気現象が、検出装置の性能（例えば、保護リレーの閾値）によって区別されているだけといえる。後記するように、本実施形態では、事故予兆及び事故の両者に適用可能な技術を提供する。これにより、従来の保護リレーでは検出できない事故予兆を検出できれば、その後に起こる事故の未然防止に繋がる。 It can be said that an accident and an accident sign are only distinguished by the performance of the detection device (for example, the threshold value of the protection relay) of the electrical phenomenon caused by the same factor. As will be described later, the present embodiment provides a technique applicable to both an accident sign and an accident. As a result, if an accident sign that cannot be detected by a conventional protection relay can be detected, it will lead to prevention of subsequent accidents.
　ところで、電力系統には、多くの種類の計測機器（センサ）が設置されている。例えば、電圧及び電流の波形を採取可能なセンサ付き開閉器、ＳＶＲ（Step Voltage Regulator）等の電圧調整機器や変電所の保護リレーを構成するセンサ等がある。系統に連系する分散電源、ＰＣＳ（Power Conditioning System）等の機器にもセンサが搭載されている。また、近年では、各種のデータ伝送手段、データ処理装置の性能向上が著しい。これらの計測機器を用いることで、電力系統に起きる電気現象を、実効値や位相だけではなく、瞬時値（波形）として計測できるようになってきている。例えば、センサ付き開閉器と子局との組合せで、瞬時値（波形）計測、データ処理、及びデータ伝送を実現する構成がある。下記の各実施形態では、これらの電力系統の計測信号を事故や事故予兆の検出に利用するものである。 By the way, many types of measuring devices (sensors) are installed in the power system. For example, there are switches with sensors that can collect voltage and current waveforms, voltage regulators such as SVRs (Step Voltage Regulators), and sensors that make up protection relays in substations. Sensors are also installed in devices such as distributed power sources and PCS (Power Conditioning System) that are connected to the grid. Further, in recent years, the performance of various data transmission means and data processing devices has been remarkably improved. By using these measuring devices, it has become possible to measure electrical phenomena occurring in an electric power system not only as effective values and phases but also as instantaneous values (waveforms). For example, there is a configuration that realizes instantaneous value (waveform) measurement, data processing, and data transmission by combining a switch with a sensor and a slave station. In each of the following embodiments, the measurement signals of these power systems are used for detecting an accident or an accident sign.
（第１実施形態）
　図１は、本発明の第１実施形態である電力系統監視装置が地絡事故を検出する検出方法を説明する説明図である。
　電力系統Ｓ１は、三相の電力系統であり、電源としての変圧器１と、負荷６との間が送電線で接続されたものである。送電線には、各々の電線（線路）と対地との間に静電容量ＣＬ，ＣＲが存在する。なお、変圧器１に並列して、他の変圧器８が接続される。なお、変圧器１は、スター結線であり、中性点が接地されている。 (First Embodiment)
FIG. 1 is an explanatory diagram illustrating a detection method in which the power system monitoring device according to the first embodiment of the present invention detects a ground fault.
The electric power system S1 is a three-phase electric power system in which a transformer 1 as a power source and a load 6 are connected by a transmission line. The transmission line, the capacitance C L, is C R exists between the ground and each of the wires (lines). In addition, another transformer 8 is connected in parallel with the transformer 1. The transformer 1 has a star connection, and the neutral point is grounded.
　電力系統Ｓ１では、樹木等が電線に接触したり、設備の絶縁不良があったりして、送電線と大地との間に想定外の電気回路を形成して、三相電圧、三相電流に関わる過渡的な電気現象（例えば、地絡）を引き起こすことがある。例えば、樹木等が電線に接触した事故点を地絡点Ｐと称する。地絡事故や事故予兆時に電源側から地絡点Ｐに向かって正の零相電流Ｉα１が流れ、負荷側から地絡点Ｐに向かって零相電流Ｉα２（電源側から地絡点Ｐに向かう電流を正の値とすれば、負の値）が流れる。なお、図では、樹木等が電線に接触した事故点の接触抵抗をＲＧと表記している。 In the power system S1, trees or the like come into contact with electric wires, or equipment insulation is poor, forming an unexpected electric circuit between the transmission line and the ground, resulting in three-phase voltage and three-phase current. It can cause transient electrical phenomena involved (eg, ground faults). For example, the accident point where a tree or the like comes into contact with an electric wire is referred to as a ground fault point P. At the time of a ground fault or an accident sign, a positive zero-phase current Iα1 flows from the power supply side toward the ground fault point P, and a zero-phase current Iα2 (from the power supply side toward the ground fault point P) flows from the load side toward the ground fault point P. If the current is a positive value, a negative value) will flow. In the figure, the contact resistance at the accident point where a tree or the like comes into contact with an electric wire is indicated by RG.
　地絡点Ｐに向かって流れる零相電流Ｉα１，Ｉα２は、正負に振れる振動波形であり、また波形が歪む（高調波成分が発生する）ことが知られている。また、事故予兆の継続時間は、事前に定まるものではない。したがって、予兆波形の実効値や位相を精度よく計測することは困難である。特に、位相を計測するためのゼロクロス点を正確に検出することは困難である。そこで、本実施形態では、零相電流の瞬時値（波形）を計測するものの、ゼロクロス点を検出することなく、波形（時系列信号）の分析により、事故や事故予兆の電気現象を捉えることにする。 It is known that the zero-phase currents Iα1 and Iα2 flowing toward the ground fault point P are vibration waveforms that swing positively and negatively, and that the waveform is distorted (harmonic components are generated). In addition, the duration of the accident sign is not fixed in advance. Therefore, it is difficult to accurately measure the effective value and phase of the precursor waveform. In particular, it is difficult to accurately detect the zero cross point for measuring the phase. Therefore, in the present embodiment, although the instantaneous value (waveform) of the zero-phase current is measured, the electrical phenomenon of an accident or an accident sign is captured by analyzing the waveform (time-series signal) without detecting the zero cross point. do.
　具体的には、電力系統監視装置１００（図２）は、微地絡（地絡の予兆）又は地絡事故が発生したときに、瞬時値として計測する零相電流の以下の性質を利用して波形分析を行う。
　性質１：電源側から地絡点Ｐに向かって流れる零相電流と負荷側から地絡点Ｐに向かって流れる零相電流とは、同一の地絡原因によって作られる電気回路を流れるため、電流波形は「相似」である。
　性質２：電源側から地絡点Ｐに向かって流れる零相電流と負荷側から地絡点Ｐに向かって流れる零相電流は、流れる方向が逆向きになるため電流の符号が反転する。
　 Specifically, the power system monitoring device 100 (FIG. 2) utilizes the following properties of the zero-phase current measured as an instantaneous value when a microground fault (a sign of a ground fault) or a ground fault accident occurs. Perform waveform analysis.
Property 1: The zero-phase current flowing from the power supply side toward the ground fault point P and the zero-phase current flowing from the load side toward the ground fault point P flow through an electric circuit created by the same ground fault cause, so that the current flows. The waveform is "similar".
Property 2: The zero-phase current flowing from the power supply side toward the ground fault point P and the zero-phase current flowing from the load side toward the ground fault point P have opposite current signs because the flowing directions are opposite.
　ここで、「相似」とは、複数の図形がスケール変換（拡大・縮小・シフト等）することで合同になる関係である。ある電気現象を複数の計測機器で計測する場合、線路距離（線路インピーダンス）の違い、あるいは計測機器の応答速度の違い等により、波形の位相（時間方向の波形の位置）と波高（波形の振幅）との何れか一方又は双方が一致しない場合がある。
そこで、本実施形態では、波高と位相とについてスケール変換して波形が一致するとき相似であるとする。 Here, "similarity" is a relationship in which a plurality of figures are congruent by scale conversion (enlargement / reduction, shift, etc.). When measuring a certain electrical phenomenon with multiple measuring instruments, the phase of the waveform (position of the waveform in the time direction) and the wave height (amplitude of the waveform) due to the difference in the line distance (line impedance) or the response speed of the measuring instrument, etc. ), Either one or both may not match.
Therefore, in the present embodiment, it is assumed that the wave height and the phase are similar when the waveforms are scale-converted and the waveforms match.
　また、電流が流れる向き、つまり電流の符号（±）が反転することは、波形の振幅が正負反転することである。しかしながら、事故時の零相電流は正負に振れる振動波形であるため、一つの瞬時値から波形の反転を判定するのは困難である。本実施形態では、図４を用いて説明するように、相関係数を用いて、符号の判定を行う。 Also, the direction in which the current flows, that is, the sign (±) of the current is inverted, means that the amplitude of the waveform is positive or negative inverted. However, since the zero-phase current at the time of an accident is a vibration waveform that swings positively and negatively, it is difficult to determine the inversion of the waveform from one instantaneous value. In the present embodiment, as will be described with reference to FIG. 4, the sign is determined using the correlation coefficient.
　図２は、隣接する接続点での零相電流の相関係数を用いた地絡事故判定の構成図である。
　電力系統Ｓ１は、電源としての変圧器１と、負荷６と、その間に接続された２つの開閉器２，３と、電力系統監視装置１００とを備えたものである。ここでは、２つの開閉器２，３の間で地絡が発生したものとする。開閉器２，３は、電気的な開閉を行うと共に、零相電流Ｉα１，Ｉα２を測定するセンサ機能を有する。 FIG. 2 is a configuration diagram of a ground fault determination using the correlation coefficient of the zero-phase currents at adjacent connection points.
The power system S1 includes a transformer 1 as a power source, a load 6, two switches 2 and 3 connected between the loads 6, and a power system monitoring device 100. Here, it is assumed that a ground fault has occurred between the two switches 2 and 3. The switches 2 and 3 have a sensor function for electrically opening and closing and measuring zero-phase currents Iα1 and Iα2.
　電力系統監視装置１００は、受信手段１０と、制御部５０と、出力部４０とを備える。受信手段１０は、２つの計測点（開閉器２，３）で計測した零相電流Ｉα１，Ｉα２の波形の信号（時系列信号、計測信号）を受信し、不図示の揮発性記憶部（レジスタ）に格納する。制御部５０は、相似性算出手段２０としての相関係数算出手段２５と、電気現象判定手段３０としての地絡判定手段３１とを備える。出力部４０は、地絡判定手段３１が地絡又は地絡予兆を判定した判定結果を表示する。また、出力部４０は、地絡判定手段３１が地絡又は地絡予兆を判定した判定結果を外部機器に送信することもできる。なお、計測信号に含まれる不要な周波数成分を除去するために適宜の周波数フィルタ手段（不図示）を備えてもよい。 The power system monitoring device 100 includes a receiving means 10, a control unit 50, and an output unit 40. The receiving means 10 receives the waveform signals (time series signal, measurement signal) of the zero-phase currents Iα1 and Iα2 measured at the two measurement points (switches 2 and 3), and is a volatile storage unit (register) (not shown). ). The control unit 50 includes a correlation coefficient calculating means 25 as a similarity calculating means 20 and a ground fault determining means 31 as an electrical phenomenon determining means 30. The output unit 40 displays the determination result that the ground fault determining means 31 has determined the ground fault or the ground fault sign. Further, the output unit 40 can also transmit the determination result that the ground fault determining means 31 has determined the ground fault or the sign of the ground fault to the external device. An appropriate frequency filter means (not shown) may be provided in order to remove unnecessary frequency components included in the measurement signal.
　図３は、零相電流の相関係数を算出する算出方法を説明する説明図である。
　実線は開閉器２が計測した零相電流Ｉα１であり、破線は開閉器３が計測した零相電流Ｉα２である。２つの零相電流Ｉα１，Ｉα２を積和すると一点鎖線で示す相間値が得られる。
　相関係数算出手段２５は、零相電流Ｉα１，Ｉα２の相関係数を演算する。相関係数は、分子に積和値（時間経過に沿って同時刻の二つの信号値を掛け合わせた値）を持ち、分母に正規化係数を持つ形である。相関係数は、分子を分母で割り算することで±１の範囲内の実数値として得られる。また、相関係数が０のとき無相関、０より大きいときに正の相関、０より小さいときに負の相関を示す。 FIG. 3 is an explanatory diagram illustrating a calculation method for calculating the correlation coefficient of the zero-phase current.
The solid line is the zero-phase current Iα1 measured by the switch 2, and the broken line is the zero-phase current Iα2 measured by the switch 3. By summing the two zero-phase currents Iα1 and Iα2, the interphase value indicated by the alternate long and short dash line is obtained.
The correlation coefficient calculating means 25 calculates the correlation coefficient of the zero-phase currents Iα1 and Iα2. The correlation coefficient has a product-sum value (a value obtained by multiplying two signal values at the same time along the passage of time) in the numerator and a normalization coefficient in the denominator. The correlation coefficient is obtained as a real value within the range of ± 1 by dividing the numerator by the denominator. Further, when the correlation coefficient is 0, no correlation is shown, when it is larger than 0, it shows a positive correlation, and when it is less than 0, it shows a negative correlation.
　図４は、２つの零相電流が相似かつ反転しているときの軌跡を示す図である。
　２つの零相電流Ｉα１，Ｉα２を二次元空間にプロットすれば直線になる。このとき、２つの計測信号の符号の組み合わせで象限が決まり、両者の符号が反転している場合は、軌跡は第二象限又は第四象限に存在する。つまり、二つの計測信号の軌跡が第二象限又は第四象限で直線を描くならば、波形反転した相似形であることが分かる。これにより、地絡事故があると判定される。 FIG. 4 is a diagram showing a locus when two zero-phase currents are similar and inverted.
If two zero-phase currents Iα1 and Iα2 are plotted in a two-dimensional space, a straight line is obtained. At this time, if the quadrant is determined by the combination of the signs of the two measurement signals and the signs of both are inverted, the locus exists in the second quadrant or the fourth quadrant. That is, if the loci of the two measurement signals draw a straight line in the second quadrant or the fourth quadrant, it can be seen that the waveform is inverted and similar. As a result, it is determined that there is a ground fault.
　２つの零相電流Ｉα１，Ｉα２の波形が相似であり、電流が流れる方向が逆向きであれば相関係数は負になることを利用して、相関係数を地絡事故の検出に適用できる。相関係数は、二つの信号（零相電流Ｉα１，Ｉα２）の積をある区間（例えば、時間ｔ＝２２～３６［ｍＳｅｃ］）に渡って累積及び正規化して算出する実数値であり、２つの波形が相似であるときに最大値をとる。 The correlation coefficient can be applied to the detection of a ground fault by utilizing the fact that the waveforms of the two zero-phase currents Iα1 and Iα2 are similar and the correlation coefficient is negative if the current flows in opposite directions. .. The correlation coefficient is a real value calculated by accumulating and normalizing the product of two signals (zero-phase currents Iα1 and Iα2) over a certain interval (for example, time t = 22 to 36 [mSec]). It takes the maximum value when two waveforms are similar.
　地絡判定手段３１は、零相電流Ｉα１，Ｉα２の波形が相似であり、かつ波形が反転しているとき、二つの計測点の間に地絡点Ｐ（図１）が存在していると判定する。相関係数の絶対値は相似性を示すので、波形が相似かつ反転の条件は、相関係数の絶対値が所定値以上であり、かつ負の相関係数が得られるときに満たしていることになる。言い換えれば、負の相関係数である場合、相関係数の絶対値が大きな値であるときに、相似性が高く、相関係数の絶対値が小さな値であるときに、相似性が低い。 The ground fault determining means 31 states that when the waveforms of the zero-phase currents Iα1 and Iα2 are similar and the waveforms are inverted, the ground fault point P (FIG. 1) exists between the two measurement points. judge. Since the absolute value of the correlation coefficient shows similarity, the condition that the waveform is similar and inverted is satisfied when the absolute value of the correlation coefficient is equal to or more than a predetermined value and a negative correlation coefficient is obtained. become. In other words, in the case of a negative correlation coefficient, the similarity is high when the absolute value of the correlation coefficient is large, and the similarity is low when the absolute value of the correlation coefficient is small.
　以上説明したように、本実施形態の電力系統監視装置１００は、電力系統の複数の計測信号（零相電流Ｉα１，Ｉα２）の相似性（相関係数）を利用して、電力系統に起きている電気現象（地絡事故や事故予兆）を検出する。つまり、電力系統監視装置１００は、２つの計測点（開閉器２，３）に流れる零相電流Ｉα１，Ｉα２の波形の相関係数の絶対値が所定値以上であり、相関係数の符号が反転しているとき、二つの計測点の間に地絡点Ｐ（図１）が存在していると判定する。言い換えれば、電力系統監視装置１００は、相似性が低いときに正常と判定し、相似性が高いときに事故予兆があると判定する。 As described above, the power system monitoring device 100 of the present embodiment uses the similarity (correlation coefficient) of a plurality of measurement signals (zero-phase currents Iα1, Iα2) of the power system to occur in the power system. Detects existing electrical phenomena (ground faults and signs of accidents). That is, in the power system monitoring device 100, the absolute value of the correlation coefficient of the waveforms of the zero-phase currents Iα1 and Iα2 flowing through the two measurement points (switches 2 and 3) is equal to or more than a predetermined value, and the sign of the correlation coefficient is When inverted, it is determined that the ground fault point P (FIG. 1) exists between the two measurement points. In other words, the power system monitoring device 100 determines that it is normal when the similarity is low, and determines that there is an accident sign when the similarity is high.
　ここで、零相電流は、三相交流の各相の電流を足し合わせて算出するものであるから、零相電流に含まれる波形は、三相交流のいずれかの相の電流に含まれている場合が多い。そこで、事故予兆があると判定したときに、零相電流と各相電流との相似性を算出して、最も相似性が高い相が地絡している相（地絡相）であると判定することができる。 Here, since the zero-phase current is calculated by adding the currents of each phase of the three-phase alternating current, the waveform included in the zero-phase current is included in the current of any one phase of the three-phase alternating current. In many cases. Therefore, when it is determined that there is an accident sign, the similarity between the zero-phase current and each phase current is calculated, and it is determined that the phase with the highest similarity is the phase in which the ground fault occurs (ground fault phase). can do.
（第２実施形態）
　前記第１実施形態では、相似性として相間係数を用いたが、これを限定するものではない。例えば、以下の尺度を利用することができる。
（１）スケール変換した波形が一致する一致度合い（類似度）を算出する
（２）波形を周波数成分に変換したのち、周波数成分の一致度合い（類似度）を算出する
（３）二つの波形の二乗誤差を算出する
（４）二つの波形の時間シフト量（位相）及び増幅率（波高）を未知変数として、両者の相似性（例えば、二乗誤差）をコスト関数として、コスト最小となる条件を数値探索（例えば、粒子群最適化手法等による最適計算）することで相似性を算出する。
　なお、いずれも、波形の符号の反転の有無についても変数として扱い（つまり、正負の符号の両方について相似性を計算する）、相似性が高くなる符号（正負のいずれか）が正しいとしてもよい。 (Second Embodiment)
In the first embodiment, the interphase coefficient is used as the similarity, but the similarity is not limited thereto. For example, the following scales can be used.
(1) Calculate the degree of matching (similarity) that the scale-converted waveforms match (2) After converting the waveform into frequency components, calculate the degree of matching (similarity) of the frequency components (3) Of the two waveforms Calculate the square error (4) Using the time shift amount (phase) and amplification factor (wave height) of the two waveforms as unknown variables, and the similarity between the two waveforms (for example, the square error) as a cost function, the condition that minimizes the cost is set. The similarity is calculated by performing a numerical search (for example, optimum calculation by a particle group optimization method or the like).
In each case, the presence or absence of inversion of the sign of the waveform is also treated as a variable (that is, the similarity is calculated for both the positive and negative signs), and the sign with high similarity (either positive or negative) may be correct. ..
　図５は、本発明の第２実施形態である電力系統監視装置の構成を示す構成図である。
　電力系統監視装置１０１は、前記第１実施形態と同様に、受信手段１０と、相似性算出手段２０と、地絡判定手段３１とを備えて構成される。 FIG. 5 is a configuration diagram showing a configuration of a power system monitoring device according to a second embodiment of the present invention.
Similar to the first embodiment, the power system monitoring device 101 includes a receiving means 10, a similarity calculating means 20, and a ground fault determining means 31.
　受信手段１０は、零相電流Ｉα１，Ｉα２の波形を計測した計測信号（時系列信号）を受信し、受信した計測信号をレジスタ１１に格納する。相似性算出手段２０は、スケール変換手段２１と、類似度算出手段２２と、最大類似度判定手段２３と、変数変更手段２４とを備える。 The receiving means 10 receives a measurement signal (time series signal) that measures the waveforms of the zero-phase currents Iα1 and Iα2, and stores the received measurement signal in the register 11. The similarity calculation means 20 includes a scale conversion means 21, a similarity calculation means 22, a maximum similarity determination means 23, and a variable change means 24.
　スケール変換手段２１は、時間シフト量（位相）及び増幅率（波高）を変数として、一方の零相電流Ｉα２の波形に対して波高及び位相のスケール変換を行う。類似度算出手段２２は、他方の零相電流Ｉα１の波形とスケール変換した零相電流波形Ｇ・Ｉα２との類似度を算出する。ここで、類似度は、内積、なす角の余弦、共分散、相関係数、相関関数等により求められる。つまり、類似度は、必ずしも規格化されているとは限らない。最大類似度判定手段２３は、スケール変換手段２１の変数を変更しつつ、類似度算出手段２２が演算した類似度の中で最大の類似度を出力する。つまり、最大類似度判定手段２３は、波高や位相の変数を数値探索する。 The scale conversion means 21 performs scale conversion of the wave height and the phase with respect to the waveform of one of the zero-phase currents Iα2, using the time shift amount (phase) and the amplification factor (wave height) as variables. The similarity calculation means 22 calculates the similarity between the waveform of the other zero-phase current Iα1 and the scale-converted zero-phase current waveforms G and Iα2. Here, the similarity is obtained by the inner product, the cosine of the angle formed, the covariance, the correlation coefficient, the correlation function, and the like. That is, the similarity is not always standardized. The maximum similarity determination means 23 outputs the maximum similarity among the similarity calculated by the similarity calculation means 22 while changing the variables of the scale conversion means 21. That is, the maximum similarity determination means 23 numerically searches for variables of wave height and phase.
　変数変更手段２４は、最大類似度判定手段２３の指示で、スケール変換手段２１の変数を変更する。つまり、最大類似度判定手段２３は、類似度算出手段２２が演算した類似度が過去に演算した類似度よりも小さいときに、変数変更手段２４に対して、変数（波高・位相）の減少を指示する。一方、最大類似度判定手段２３は、類似度算出手段２２が演算した類似度が過去に演算した類似度よりも大きいときには、変数変更手段２４に対して、変数の増加を指示する。これにより、最大類似度判定手段２３は、類似度算出手段２２が演算した類似度の中で最大の類似度を出力する。 The variable changing means 24 changes the variable of the scale conversion means 21 according to the instruction of the maximum similarity determining means 23. That is, when the similarity calculated by the similarity calculating means 22 is smaller than the similarity calculated in the past, the maximum similarity determining means 23 reduces the variable (wave height / phase) with respect to the variable changing means 24. Instruct. On the other hand, when the similarity calculated by the similarity calculating means 22 is larger than the similarity calculated in the past, the maximum similarity determining means 23 instructs the variable changing means 24 to increase the variables. As a result, the maximum similarity determination means 23 outputs the maximum similarity among the similarity calculated by the similarity calculation means 22.
　地絡判定手段３１は、類似度算出手段２２が演算した類似度が最大の場合、２つの零相電流Ｉα１，Ｉα２の相関係数の符号が反転しているときに、地絡と判定する。ここで、相関係数の正負の符号だけを用いて判定し、絶対値が不要の場合は、相関係数の正規化（分子を分母で割り算する）は不要になり、分子だけを算出すればよい。 The ground fault determining means 31 determines that the ground fault is a ground fault when the similarity calculated by the similarity calculating means 22 is the maximum and the signs of the correlation coefficients of the two zero-phase currents Iα1 and Iα2 are inverted. Here, the judgment is made using only the positive and negative signs of the correlation coefficient, and if the absolute value is unnecessary, the normalization of the correlation coefficient (dividing the numerator by the denominator) becomes unnecessary, and only the numerator can be calculated. good.
　なお、上記手順に示していないが、制御部５０は、計測信号の前処理として、波高の正規化（例えば、１波高最大値を１．０にする）、オフセット除去（例えば、短期平均値を０．０にする）等を行っても構わない。また、相関係数を算出する波形（時系列信号）の時間幅は、限定するものではないが、１周期以下の波形からも算出可能である。一方、時間幅を広げるほどノイズ等の影響が減り安定な結果が得られる。 Although not shown in the above procedure, the control unit 50 normalizes the wave height (for example, sets the maximum value of one wave height to 1.0) and removes the offset (for example, the short-term average value) as preprocessing of the measurement signal. You may do (set to 0.0) and so on. Further, the time width of the waveform (time series signal) for which the correlation coefficient is calculated is not limited, but can be calculated from a waveform having one cycle or less. On the other hand, the wider the time width, the less the influence of noise and the like, and stable results can be obtained.
　相関係数の判定に何らかのパラメータを組み合わせてもよい。例えば、ノイズ耐性を高めるため、相関係数の大きさを判定する閾値をパラメータとしてもよい。また、判定結果の継続時間に関する閾値をパラメータとして用意して、負の相関が一定時間以上継続したときに予兆あるいは事故が検出されたと判定することができる。地絡点から計測点までの線路に電源や負荷等がある場合、波形の相似性が低下することがあるので、適度な余裕をパラメータ設定して相似性を判定することができる。本発明は、判定に用いるパラメータを限定するものではない。 Some parameters may be combined to determine the correlation coefficient. For example, in order to increase noise immunity, a threshold value for determining the magnitude of the correlation coefficient may be used as a parameter. In addition, a threshold value regarding the duration of the determination result can be prepared as a parameter, and it can be determined that a sign or an accident has been detected when the negative correlation continues for a certain period of time or longer. If there is a power supply, load, etc. on the line from the ground fault point to the measurement point, the similarity of the waveforms may decrease, so it is possible to determine the similarity by setting an appropriate margin as a parameter. The present invention does not limit the parameters used for the determination.
（第３実施形態）
　前記第１，２実施形態では、地絡事故又は事故予兆を検知したが、短絡事故又は事故予兆の検知を行うこともできる。 (Third Embodiment)
In the first and second embodiments, a ground fault or an accident sign is detected, but a short circuit accident or an accident sign can also be detected.
　図６は、本発明の第３実施形態である電力系統監視装置が短絡事故を検出する検出方法を説明する説明図である。
　電力系統Ｓ２は、電源としての変圧器１と、負荷６と、その間に接続された開閉器２，３とを備えている。電力系統Ｓ２の３相の電線（線路）のうち、何れか２相の電線又は３相全ての電線が接触して、電流ｉａ，ｉｂが流れる電気回路を形成する事故を短絡事故と呼ぶ。短絡点Ｑでは、短絡した２相又は３相の線路が電気的に接続されることから、短絡相の相電位は同値になる。また、短絡相間では、電流の流入や流出が起きる。 FIG. 6 is an explanatory diagram illustrating a detection method in which the power system monitoring device according to the third embodiment of the present invention detects a short circuit accident.
The power system S2 includes a transformer 1 as a power source, a load 6, and switches 2 and 3 connected between the loads 6. Of the three-phase electric wires (lines) of the power system S2, an accident in which any two-phase electric wire or all three-phase electric wires come into contact to form an electric circuit through which currents ia and ib flow is called a short-circuit accident. At the short-circuit point Q, the short-circuited two-phase or three-phase lines are electrically connected, so that the phase potentials of the short-circuit phases are the same. In addition, current inflow and outflow occur between the short-circuit phases.
　電力系統Ｓが正常の状態にある場合には、３相交流の電圧と電流とは、各相間で１２０度の位相ずれの関係にあるが、短絡事故が起きたときには（短絡点において共通の電気回路を持つことから）短絡相の電圧と電流とは同相成分を含むことになる。例えば、３相の全てが短絡するとき、短絡点において電圧は共通となり、電流は相互に流れることから、３相交流の電圧と電流とは、同相成分を含むことになる。これらの現象を電圧ベクトルの大きさ及び位相を用いて判定しようにも、予兆波形が微小で歪みのあるとき、実効値あるいは位相の誤差が大きくなり、判定の信頼性が劣る。 When the power system S is in a normal state, the voltage and current of the three-phase AC have a phase shift of 120 degrees between each phase, but when a short-circuit accident occurs (common electricity at the short-circuit point). The voltage and current of the short-circuit phase (because of having a circuit) include in-phase components. For example, when all three phases are short-circuited, the voltage is common at the short-circuit point and the currents flow with each other. Therefore, the voltage and current of the three-phase alternating current include in-phase components. Even if these phenomena are judged using the magnitude and phase of the voltage vector, when the predictive waveform is minute and distorted, the error of the effective value or the phase becomes large, and the reliability of the judgment is inferior.
　本実施形態の電力系統監視装置では、短絡事故によって起きる電気現象を、各相の計測信号の相似性を用いて判定する。開閉器２，３の３相をa，b，cで表記するならば、例えば、下記の各相電圧の組合せで波形の相似性を算出して短絡の有無を判定する。
 
・a相の相電圧とb相の相電圧との相似性、b相の相電圧とc相の相電圧との相似性、c相の相電圧とa相の相電圧との相似性 のうち一組も相似性がない （短絡事故無し）
・a相の相電圧とb相の相電圧との相似性、b相の相電圧とc相の相電圧との相似性、c相の相電圧とa相の相電圧との相似性 のうち一組に相似性がある （２相短絡事故あり）
・a相の相電圧とb相の相電圧との相似性、b相の相電圧とc相の相電圧との相似性、c相の相電圧とa相の相電圧との相似性 のうち二組に相似性がある （２相短絡事故が二組あり）
・a相の相電圧とb相の相電圧との相似性、b相の相電圧とc相の相電圧との相似性、c相の相電圧とa相の相電圧との相似性 のうち全てに相似性がある　      　（３相短絡事故あり）
　つまり、電力系統監視装置は、少なくとも２つの相の相電圧の相似性が高いときに、短絡事故又は予兆があると判定し、相似性が低いときに短絡事故又は事故予兆が無いと判定する。この判定は、前記した相関係数の算出結果を用いて行うことができる。つまり、電力系統監視装置は、少なくとも２つの相の相電圧の相関係数の絶対値が所定値以上のときに、断線事故又は予兆があると判定し、相関係数の絶対値が所定値未満のときに短絡事故又は事故予兆が無いと判定する。 In the power system monitoring device of the present embodiment, the electrical phenomenon caused by the short-circuit accident is determined by using the similarity of the measurement signals of each phase. If the three phases of the switches 2 and 3 are represented by a, b, and c, for example, the similarity of the waveform is calculated by the combination of the following phase voltages to determine the presence or absence of a short circuit.

-Of the similarity between the phase a phase voltage and the phase voltage of the b phase, the similarity between the phase voltage of the b phase and the phase voltage of the c phase, and the similarity between the phase voltage of the c phase and the phase voltage of the a phase. No pair is similar (no short circuit accident)
-Of the similarity between the phase a phase voltage and the phase voltage of the b phase, the similarity between the phase voltage of the b phase and the phase voltage of the c phase, and the similarity between the phase voltage of the c phase and the phase voltage of the a phase. There is a similarity in one set (there is a two-phase short circuit accident)
-Of the similarity between the phase a phase voltage and the phase voltage of the b phase, the similarity between the phase voltage of the b phase and the phase voltage of the c phase, and the similarity between the phase voltage of the c phase and the phase voltage of the a phase. There are similarities between the two sets (there are two sets of two-phase short circuit accidents)
-Of the similarity between the phase a-phase voltage and the b-phase voltage, the similarity between the b-phase voltage and the c-phase phase voltage, and the similarity between the c-phase phase voltage and the a-phase phase voltage. All are similar (with 3-phase short circuit accident)
That is, the power system monitoring device determines that there is a short-circuit accident or a sign when the similarity of the phase voltages of at least two phases is high, and determines that there is no short-circuit accident or a sign of an accident when the similarity is low. This determination can be made using the above-mentioned calculation result of the correlation coefficient. That is, the power system monitoring device determines that there is a disconnection accident or a sign when the absolute value of the correlation coefficient of the phase voltage of at least two phases is equal to or more than the predetermined value, and the absolute value of the correlation coefficient is less than the predetermined value. At this time, it is judged that there is no short circuit accident or no sign of accident.
　本発明は、各相の計測信号の相似性を、相関係数等を用いて算出し、算出された相似性を用いて、短絡事故の様相を判定するものである。相関係数は、ある期間の波形（時系列信号）を用いて算出することから、微小で歪みのある波形についても安定した結果が得られる。波形（時系列信号）の期間幅とサンプリング周期は限定するものではないが、１周期以下の波形からも算出可能であり、一方、時間幅を広げるほどノイズ等の影響が減り安定な結果が得られる。 According to the present invention, the similarity of the measurement signals of each phase is calculated by using a correlation coefficient or the like, and the aspect of the short circuit accident is determined by using the calculated similarity. Since the correlation coefficient is calculated using a waveform (time series signal) for a certain period, stable results can be obtained even for a minute and distorted waveform. The period width and sampling period of the waveform (time series signal) are not limited, but it can be calculated from waveforms of one cycle or less. On the other hand, the wider the time width, the less the influence of noise, etc., and stable results are obtained. Be done.
　短絡事故では、開閉器２，３の何れか一方で計測した３相の電圧信号（計測信号）のみで判定可能であるが、さらに精度を高めるため、開閉器２，３の双方の計測信号を用いて判定してもよい。
　短絡点から計測点までの線路に電源又は負荷がある場合、波形の相似性は低下するときがある。そこで、適度な余裕を持たせて相似性の判定することで、精度と誤判定のバランスを調整することができる。上記の判定は、前記した相関係数の算出結果から判定できることはいうまでもない。 In a short-circuit accident, it is possible to make a judgment only with the three-phase voltage signal (measurement signal) measured by either of the switches 2 and 3, but in order to further improve the accuracy, the measurement signals of both switches 2 and 3 are used. It may be judged by using.
If there is a power supply or load on the line from the short-circuit point to the measurement point, the similarity of the waveforms may decrease. Therefore, the balance between accuracy and erroneous determination can be adjusted by determining the similarity with an appropriate margin. Needless to say, the above determination can be made from the above-mentioned calculation result of the correlation coefficient.
（第４実施形態）
　前記第１，２実施形態では、地絡事故又は予兆を検知し、前記第３実施形態では、短絡事故又は予兆を検知したが、断線事故又はその予兆を検知することもできる。 (Fourth Embodiment)
In the first and second embodiments, a ground fault or a sign is detected, and in the third embodiment, a short-circuit accident or a sign is detected, but a disconnection accident or a sign thereof can also be detected.
　図７は、本発明の第４実施形態である電力系統監視装置が断線事故を検出する検出方法を説明する説明図である。
　電力系統Ｓ３は、電源としての変圧器１と、負荷６と、その間に接続された開閉器２，３とを備えている。電力系統Ｓ３の３相の線路のうち、少なくとも１相の線路が開放された状態になる事故を断線事故と呼ぶ。例えば、電線が切れて垂れ下がっている状況である。この状態では、断線点Ｒで断線した相電流ｉα１，ｉα２が流れない。電気的に開放された相については、断線点Ｒを挟む電源側の相電圧と負荷側の相電圧とは、計測信号の相似性が無い。 FIG. 7 is an explanatory diagram illustrating a detection method in which the power system monitoring device according to the fourth embodiment of the present invention detects a disconnection accident.
The power system S3 includes a transformer 1 as a power source, a load 6, and switches 2 and 3 connected between the loads 6. An accident in which at least one phase of the three-phase lines of the power system S3 is open is called a disconnection accident. For example, the electric wire is cut and hangs down. In this state, the phase currents iα1 and iα2 that are disconnected at the disconnection point R do not flow. For the electrically open phase, the phase voltage on the power supply side and the phase voltage on the load side with the disconnection point R in between are not similar in measurement signals.
　そこで、本実施形態の電力系統監視装置では、上記の断線事故によって起きる電気現象を、計測信号の相似性を用いて判定する。３相交流の各相について、電源側と負荷側の相電圧又は相電流の相似性を算出する。
 
・電源側の相電圧と負荷側の相電圧とで相似性がある （断線事故無し）
・電源側の相電圧と負荷側の相電圧とで相似性がない （断線事故あり）
・電源側の相電流と負荷側の相電流とで相似性がある （断線事故無し）
・電源側の相電流と負荷側の相電流とで相似性がない （断線事故あり）
 
　つまり、電力系統監視装置は、少なくとも２つの相の相電圧の相似性が低いときに、断線事故又は予兆があると判定し、相似性が高いときに短絡事故又は事故予兆が無いと判定する。この判定は、前記した相関係数の算出結果を用いて行うことができる。つまり、電力系統監視装置は、少なくとも２つの相の相電圧の相関係数の絶対値が所定値未満のときに、断線事故又は予兆があると判定し、相関係数の絶対値が所定値以上のときに短絡事故又は事故予兆が無いと判定する。 Therefore, in the power system monitoring device of the present embodiment, the electrical phenomenon caused by the above-mentioned disconnection accident is determined by using the similarity of the measurement signals. For each phase of three-phase alternating current, the similarity of the phase voltage or phase current on the power supply side and the load side is calculated.

-There is a similarity between the phase voltage on the power supply side and the phase voltage on the load side (no disconnection accident).
-There is no similarity between the phase voltage on the power supply side and the phase voltage on the load side (there is a disconnection accident).
-There is a similarity between the phase current on the power supply side and the phase current on the load side (no disconnection accident).
-There is no similarity between the phase current on the power supply side and the phase current on the load side (there is a disconnection accident).

That is, the power system monitoring device determines that there is a disconnection accident or a sign when the similarity of the phase voltages of at least two phases is low, and determines that there is no short-circuit accident or a sign of an accident when the similarity is high. This determination can be made using the above-mentioned calculation result of the correlation coefficient. That is, the power system monitoring device determines that there is a disconnection accident or a sign when the absolute value of the correlation coefficient of the phase voltage of at least two phases is less than the predetermined value, and the absolute value of the correlation coefficient is equal to or more than the predetermined value. At this time, it is judged that there is no short circuit accident or no sign of accident.
（第５実施形態）
　前記第１，２実施形態では、電源としての変圧器１と負荷６との間に２つの計測点（開閉器２，３）が介挿されており、その間で事故又は事故予兆が生じたことを前提としていたが、変圧器１と負荷６との間に多数の計測点（開閉器）があることもある。 (Fifth Embodiment)
In the first and second embodiments, two measurement points (switches 2 and 3) are inserted between the transformer 1 as a power source and the load 6, and an accident or an accident sign occurs between them. However, there may be a large number of measurement points (switches) between the transformer 1 and the load 6.
　図８は、本発明の第５実施形態である電力系統監視装置が、複数箇所で計測した計測信号を集約して予兆検出する構成図である。
　電力系統Ｓ４は、電源としての変圧器１と、保護リレー７と、複数の開閉器２，３，４，５と、負荷６とが直列接続されて構成されている。さらに、電力系統Ｓ４は、複数の開閉器２，３，４，５が三相電圧、三相電流を計測した計測波形を受信する電力系統監視装置１０２を有している。なお、電力系統監視装置１０２は、電力系統Ｓの三相電圧・三相電流の情報を複数の子局（開閉器２，３，４，５）から集約する集約拠点に設置されている。 FIG. 8 is a configuration diagram in which the power system monitoring device according to the fifth embodiment of the present invention aggregates the measurement signals measured at a plurality of locations and detects a sign.
The power system S4 is configured by connecting a transformer 1 as a power source, a protection relay 7, a plurality of switches 2, 3, 4, 5 and a load 6 in series. Further, the power system S4 has a power system monitoring device 102 in which a plurality of switches 2, 3, 4, and 5 receive measurement waveforms obtained by measuring a three-phase voltage and a three-phase current. The power system monitoring device 102 is installed at an aggregation base that aggregates information on the three-phase voltage and three-phase current of the power system S from a plurality of slave stations (switches 2, 3, 4, and 5).
　保護リレー７は、所定以上の零相電流が流れたことを検出する開閉器である。開閉器２，３，４，５は、時限順送方式により開閉される開閉器であり、零相電流、相電圧、相電流を検出するセンサが設けられている。 The protection relay 7 is a switch that detects that a zero-phase current exceeding a predetermined value has flowed. The switches 2, 3, 4, and 5 are switches that are opened and closed by a timed progressive system, and are provided with sensors that detect zero-phase current, phase voltage, and phase current.
　電力系統監視装置１０２は、複数の開閉器２，３，４，５が計測した零相電流の波形や各相の電圧波形及び電流波形等の波形データを時系列的に受信する拠点サーバである。電力系統監視装置１０２は、隣接する開閉器から受信した波形データを用いて、地絡事故やその予兆を検出する。また、電力系統監視装置１０２は、制御部５０及び出力部４０を備える。制御部５０は、各相の電圧波形、電流波形や零相電流を用いて、地絡事故、短絡事故、断線事故やこれらの予兆を検出する。出力部４０は、事故又は事故予兆が発生した区間や事故発生時刻等の事故内容を表示する（図１１参照）。 The power system monitoring device 102 is a base server that receives waveform data such as zero-phase current waveforms measured by a plurality of switches 2, 3, 4, and 5 and voltage waveforms and current waveforms of each phase in time series. .. The power system monitoring device 102 detects a ground fault and its sign by using the waveform data received from the adjacent switch. Further, the power system monitoring device 102 includes a control unit 50 and an output unit 40. The control unit 50 detects ground fault accidents, short-circuit accidents, disconnection accidents, and signs thereof by using the voltage waveform, current waveform, and zero-phase current of each phase. The output unit 40 displays the details of the accident such as the section where the accident or the sign of the accident occurred and the time when the accident occurred (see FIG. 11).
　図９は、拠点サーバの動作を説明するフローチャートであり、図１０は、判定処理の動作を説明するためのフローチャートである。これらは、受信した零相電流の波形を用いて、地絡事故やその予兆を検出するときのフローであるが、短絡事故、断線事故を検出するときも同様の動作を行う。ここでは、隣接する開閉器２，３の間が地絡点Ｐとする。 FIG. 9 is a flowchart for explaining the operation of the base server, and FIG. 10 is a flowchart for explaining the operation of the determination process. These are flows when detecting a ground fault or a sign thereof by using the waveform of the received zero-phase current, but the same operation is performed when detecting a short-circuit accident or a disconnection accident. Here, the ground fault point P is between the adjacent switches 2 and 3.
　拠点サーバ（電力系統監視装置１０２）の制御部５０は、予兆検出の判定処理を行い（Ｓ１０）、普及支援情報の画面表示を行う（Ｓ２０）。この画面表示により、事故の未然防止が図られる。Ｓ１０（図１０）では、制御部５０は、複数の開閉器４，２，３，５の零相電流の受信波形をバッファメモリに格納する（Ｓ１）。格納後、制御部５０は、隣接する開閉器４，２、開閉器２，３、開閉器３，５の相関係数を演算する（Ｓ２）。Ｓ２の処理後、制御部５０は、地絡予兆の検出を行う（Ｓ３）。具体的には、制御部５０は、隣接する開閉器に流れる零相電流の波形が相似であり、かつ波形が反転しているとき、その間で地絡が発生していると判定する。Ｓ３の処理後、制御部５０は、判定結果を出力部４０に出力する（Ｓ４）。 The control unit 50 of the base server (power system monitoring device 102) performs a sign detection determination process (S10) and displays the dissemination support information on the screen (S20). This screen display prevents accidents. In S10 (FIG. 10), the control unit 50 stores the received waveforms of the zero-phase currents of the plurality of switches 4, 2, 3, and 5 in the buffer memory (S1). After the storage, the control unit 50 calculates the correlation coefficient of the adjacent switches 4, 2, the switches 2, 3, and the switches 3, 5 (S2). After the processing of S2, the control unit 50 detects the sign of a ground fault (S3). Specifically, when the waveforms of the zero-phase currents flowing in the adjacent switches are similar and the waveforms are inverted, the control unit 50 determines that a ground fault has occurred between them. After the processing of S3, the control unit 50 outputs the determination result to the output unit 40 (S4).
　なお、電力系統監視装置１０２は、拠点サーバとして、複数の開閉器４，２，３，５の計測信号を常時受信することはデータ伝送路の負荷が重くなる。データ量を減らすためには、何らかのトリガを用意してデータ伝送を開始しても構わない。例えば、子局としての開閉器４，２，３，５に閾値を設定しておき、計測信号が閾値を超えたときにデータ伝送を開始する方法がある。あるいは、事故後の再閉路が成功して事故原因が特定できないまま再開する場合において、再閉路区間を対象にして、データ伝送を開始しても構わない。いずれも常時伝送に比べてデータ伝送量を減らす効果がある。本発明は、これらのデータ伝送開始のトリガを限定するものではない。 Note that the power system monitoring device 102, as a base server, constantly receives the measurement signals of the plurality of switches 4, 2, 3, and 5, which increases the load on the data transmission line. In order to reduce the amount of data, some kind of trigger may be prepared to start data transmission. For example, there is a method in which a threshold value is set in the switches 4, 2, 3 and 5 as slave stations, and data transmission is started when the measurement signal exceeds the threshold value. Alternatively, when the reclosing after the accident is successful and the cause of the accident cannot be identified, data transmission may be started for the reclosing section. Both have the effect of reducing the amount of data transmission compared to constant transmission. The present invention does not limit these triggers for starting data transmission.
　図１１は、本発明の第５実施形態である電力系統監視装置の出力部が表示する画面の一例を示す図である。
　表示画面２００は、出力部４０で表示される画面であり、電力系統の事故又はその予兆を検出したときに、事故の対処方法や復旧支援情報を示すテキストやグラフを含んでいる。 FIG. 11 is a diagram showing an example of a screen displayed by the output unit of the power system monitoring device according to the fifth embodiment of the present invention.
The display screen 200 is a screen displayed by the output unit 40, and includes texts and graphs indicating how to deal with the accident and recovery support information when an accident in the power system or a sign thereof is detected.
　表示画面２００には、事故発生時刻２１１、事故発生区間２１２、及び事故発生確率２１３からなる事故内容２１０と、復旧手順２２１、復旧時に必要な用品２２２、過去事例２２３等からなる復旧支援情報２２０とがテキストで表示される。ここで、復旧支援情報２２０は、過去の事故や対処の事例をデータベース化しておき、事故又は予兆の検出結果をもとにデータベース検索することで用意することができる。 On the display screen 200, the accident content 210 including the accident occurrence time 211, the accident occurrence section 212, and the accident occurrence probability 213, and the restoration support information 220 consisting of the restoration procedure 221 and the necessary supplies 222 at the time of restoration, the past case 223, and the like are displayed. Is displayed in text. Here, the recovery support information 220 can be prepared by creating a database of past accidents and countermeasures and searching the database based on the detection results of accidents or signs.
　事故発生時刻２１１は、事故又は事故予兆が発生した時刻である。事故発生区間２１２は、隣接する開閉器４，２の間、開閉器２，３の間、開閉器３，５の間の何れかであることが表示される。復旧手順２２１は、地絡事故、短絡事故、断線事故であるかによって異なり、例えば、「マニュアルＺ参照」と表示される。用品２２２も地絡事故、短絡事故、断線事故、及び事故発生区間２１２によって異なる。 The accident occurrence time 211 is the time when the accident or the accident sign occurred. It is displayed that the accident occurrence section 212 is any of the adjacent switches 4 and 2, between the switches 2 and 3, and between the switches 3 and 5. The restoration procedure 221 differs depending on whether it is a ground fault accident, a short circuit accident, or a disconnection accident, and is displayed as, for example, "Refer to Manual Z". The equipment 222 also differs depending on the ground fault accident, the short circuit accident, the disconnection accident, and the accident occurrence section 212.
　なお、復旧支援情報２２０は、異なる事故対応技術と組み合わせてもよい。例えば、事故区間検出技術、事故点標定技術の結果を組み合わせて、画面表示、あるいはデータベース検索に利用してもよい。さらに事故原因推定技術等が利用可能であれば、上記と組み合わせることができる。 The recovery support information 220 may be combined with different accident response technologies. For example, the results of the accident section detection technique and the accident point determination technique may be combined and used for screen display or database search. Furthermore, if accident cause estimation technology or the like is available, it can be combined with the above.
　事故発生確率２１３は、例えば、相関係数の絶対値を地絡事故の確率と見なしたり、相関係数の絶対値に所定の変換式を乗算した値を地絡事故の確率としたりして表示する。相関係数は、確率とは別の尺度であるが、±１の範囲に収まる実数である。また、相関係数の絶対値が大きいほど二つの波形が相似であることを示す。このため、相関係数の絶対値を地絡事故の確率と見なしても構わない。相関係数が０のときは地絡の確率が０として、相関関数の絶対値が１のときには完全な地絡事故（地絡の確率が１）とみなすことができる。 The accident occurrence probability 213 is displayed, for example, by regarding the absolute value of the correlation coefficient as the probability of a ground fault, or by multiplying the absolute value of the correlation coefficient by a predetermined conversion formula as the probability of a ground fault. do. The correlation coefficient is a real number that falls within the range of ± 1, although it is a different measure from the probability. Further, the larger the absolute value of the correlation coefficient, the more similar the two waveforms are. Therefore, the absolute value of the correlation coefficient may be regarded as the probability of a ground fault. When the correlation coefficient is 0, the probability of a ground fault is 0, and when the absolute value of the correlation function is 1, it can be regarded as a complete ground fault (probability of a ground fault is 1).
（第６実施形態）
　前記第５実施形態では、子局（開閉器４，２，３，５）の各々が計測した零相電流、相電圧、相電流を集約する拠点サーバが事故や事故予兆の判定を行っていたが、開閉器４，２，３，５の各々の子局が事故や事故予兆の判定を行っても構わない。 (Sixth Embodiment)
In the fifth embodiment, the base server that aggregates the zero-phase current, phase voltage, and phase current measured by each of the slave stations (switches 4, 2, 3, and 5) determines an accident or an accident sign. However, each slave station of the switch 4, 2, 3, and 5 may determine an accident or an accident sign.
　図１２は、本発明の第６実施形態である電力系統監視装置が子局として予兆検出する構成図である。
　電力系統Ｓ５は、前記第５実施形態と同様に、電源としての変圧器１と、保護リレー７と、複数の開閉器２，３，４，５と、負荷６とが直列接続されて構成されている。さらに、電力系統Ｓ５は、自装置（例えば、地絡点Ｐの負荷側の開閉器３）での零相電流、各相の電圧波形、各相の電流波形を計測すると共に、他の開閉器２，４，５が計測した波形データを受信し、事故判定や予兆判定を行う子局（電力系統監視装置１０３）を有している。 FIG. 12 is a configuration diagram in which the power system monitoring device according to the sixth embodiment of the present invention detects a sign as a slave station.
Similar to the fifth embodiment, the power system S5 is configured by connecting a transformer 1 as a power source, a protection relay 7, a plurality of switches 2, 3, 4, 5 and a load 6 in series. ing. Further, the power system S5 measures the zero-phase current, the voltage waveform of each phase, and the current waveform of each phase in its own device (for example, the switch 3 on the load side of the ground fault point P), and also another switch. It has a slave station (power system monitoring device 103) that receives waveform data measured by 2, 4 and 5 and performs accident determination and predictive determination.
　また、開閉器３の電力系統監視装置１０３は、自装置で計測した零相電流の波形データと、隣接する開閉器２，５の零相電流の波形データとで地絡事故又は予兆の判定を行う。この場合、開閉器２，３の間が地絡点Ｐであるとき、自装置で計測した零相電流の波形データと隣接する開閉器２の零相電流の波形データとの相関係数の絶対値が大きくなる。 Further, the power system monitoring device 103 of the switch 3 determines a ground fault or a sign based on the waveform data of the zero-phase current measured by its own device and the waveform data of the zero-phase currents of the adjacent switches 2 and 5. conduct. In this case, when the ground fault point P is between the switches 2 and 3, the absolute correlation coefficient between the zero-phase current waveform data measured by the own device and the zero-phase current waveform data of the adjacent switch 2 is absolute. The value increases.
　さらに、電力系統Ｓ５は、分散配置された複数の電力系統監視装置１０３からの情報（判定結果）を集約する拠点サーバ１０４を備えている。なお、複数の電力系統監視装置１０３の各々は、図示しないが、前記第５実施形態の電力系統監視装置１０２（図８）と同様に、出力部４０と制御部５０とを有している。 Further, the power system S5 includes a base server 104 that aggregates information (determination results) from a plurality of distributed power system monitoring devices 103. Although not shown, each of the plurality of power system monitoring devices 103 has an output unit 40 and a control unit 50, as in the power system monitoring device 102 (FIG. 8) of the fifth embodiment.
　図１３は、本発明の第６実施形態である電力系統監視装置の動作を説明するフローチャートである。
　このフローは、複数の電力系統監視装置１０３の何れかが処理を開始させてよく、拠点サーバ１０４が処理開始を指示しても構わない。つまり、このフローは、処理開始のトリガを限定するものではない。 FIG. 13 is a flowchart illustrating the operation of the power system monitoring device according to the sixth embodiment of the present invention.
In this flow, any one of the plurality of power system monitoring devices 103 may start the process, and the base server 104 may instruct the start of the process. That is, this flow does not limit the trigger for starting processing.
　電力系統監視装置１０３の制御部５０は、前記第５実施形態と同様に、事故又は事故予兆を検出したか否かの判定を行う（Ｓ１０）。但し、この判定処理（Ｓ１０，図１０）でのバッファメモリ格納（Ｓ１）は、自装置で計測した零相電流、相電圧、相電流と、隣接する開閉器が測定した零相電流、相電圧、相電流との双方をバッファメモリに格納する。また、結果出力（Ｓ４）でも、出力部４０が前記第５実施形態の表示画面２００（図１１）を表示する。例えば、事故発生区間２１２では、自装置に対して電源側か負荷側かが示される。 The control unit 50 of the power system monitoring device 103 determines whether or not an accident or an accident sign has been detected, as in the fifth embodiment (S10). However, in the buffer memory storage (S1) in this determination process (S10, FIG. 10), the zero-phase current, phase voltage, and phase current measured by the own device and the zero-phase current and phase voltage measured by the adjacent switch are used. , Both the phase current and the phase current are stored in the buffer memory. Further, also in the result output (S4), the output unit 40 displays the display screen 200 (FIG. 11) of the fifth embodiment. For example, in the accident occurrence section 212, the power supply side or the load side is indicated with respect to the own device.
　Ｓ１０の処理後、制御部５０は、判定結果を拠点サーバ１０４に通知する。これにより、拠点サーバ１０４は、複数の開閉器４，２，３，５が測定した零相電流、相電圧、相電流と、複数の電力系統監視装置１０３が判定した判定結果を受信する。これにより、事故の未然防止が図られる。 After the processing of S10, the control unit 50 notifies the base server 104 of the determination result. As a result, the base server 104 receives the zero-phase current, the phase voltage, and the phase current measured by the plurality of switches 4, 2, 3, and 5 and the determination result determined by the plurality of power system monitoring devices 103. As a result, accidents can be prevented.
　本実施形態は、近隣子局としての電力系統監視装置１０３との通信路の構成方法を限定しない。例えば、電力線を介した通信、電力線とは別の通信路（例えば、光ファイバ等）を介した通信、何らかの無線通信路を介した通信、等を利用することができる。また、通信路を介したデータ伝送の開始、終了の手順を限定しない。計測したデータを常時伝送する方法、何らかの閾値を超えたときにデータ伝送する方法や、要求に応えてデータ伝送する方法等がある。このように、子局間の通信機能を利用して事故や予兆を検出する方法は、データ伝送やデータ処理の負荷を軽減する効果がある。 This embodiment does not limit the method of configuring the communication path with the power system monitoring device 103 as a neighboring slave station. For example, communication via a power line, communication via a communication path different from the power line (for example, optical fiber, etc.), communication via some wireless communication path, and the like can be used. Further, the procedure for starting and ending data transmission via the communication path is not limited. There are a method of constantly transmitting the measured data, a method of transmitting data when a certain threshold is exceeded, a method of transmitting data in response to a request, and the like. As described above, the method of detecting an accident or a sign by using the communication function between slave stations has an effect of reducing the load of data transmission and data processing.
（第７実施形態）
　前記第１～第４実施形態の電力系統監視装置は、地絡、短絡、断線の何れかの事故又は事故予兆の判定を行っていたが、地絡、短絡、断線の全ての判定を行っても構わない。 (7th Embodiment)
The power system monitoring device of the first to fourth embodiments has determined any accident or accident sign of a ground fault, a short circuit, or a disconnection, but has determined all of the ground fault, the short circuit, and the disconnection. It doesn't matter.
　図１４は、本発明の第７実施形態である電力系統監視装置の構成図である。
　電力系統監視装置１０５は、受信手段１０と制御部５０と出力部４０とを備え、制御部５０には、地絡事故予兆判定手段５１と短絡事故予兆判定手段５２と断線事故予兆判定手段５３とを備える。 FIG. 14 is a configuration diagram of a power system monitoring device according to a seventh embodiment of the present invention.
The power system monitoring device 105 includes a receiving means 10, a control unit 50, and an output unit 40, and the control unit 50 includes a ground fault sign determining means 51, a short circuit accident sign determining means 52, and a disconnection accident sign determining means 53. To be equipped.
　受信手段１０は、複数の開閉器２，３，４，５が検出した零相電流、相電圧、相電流の波形信号を受信し、レジスタ１１に格納する。地絡事故予兆判定手段５１は、例えば、前記第１実施形態（図２）の相関係数算出手段２５及び地絡判定手段３１を備える。地絡事故予兆判定手段５１は、レジスタ１１に格納された隣接する開閉器２，３，４，５の相関係数を算出し、相関係数の絶対値が所定値よりも大きく、符号が反転しているときに、地絡事故又は事故予兆と判定する。短絡事故予兆判定手段５２は、レジスタ１１に格納された各相の相電圧の内、少なくとも２つの相の相電圧の相似性が高いときに、短絡事故又はその予兆があると判定する。断線事故予兆判定手段５３は、隣接する開閉器２，３，４，５の各相の相電圧又は相電流に相似性が低いときに断線事故又は予兆があると判定する。 The receiving means 10 receives the waveform signals of the zero-phase current, the phase voltage, and the phase current detected by the plurality of switches 2, 3, 4, and 5, and stores them in the register 11. The ground fault sign determining means 51 includes, for example, the correlation coefficient calculating means 25 and the ground fault determining means 31 of the first embodiment (FIG. 2). The ground fault sign determination means 51 calculates the correlation coefficient of the adjacent switches 2, 3, 4, and 5 stored in the register 11, the absolute value of the correlation coefficient is larger than the predetermined value, and the sign is inverted. When it is, it is judged as a ground fault accident or an accident sign. The short-circuit accident sign determination means 52 determines that there is a short-circuit accident or a sign thereof when the similarity of the phase voltages of at least two phases among the phase voltages of each phase stored in the register 11 is high. The disconnection accident sign determination means 53 determines that there is a disconnection accident or a precursor when the similarity to the phase voltage or phase current of each phase of the adjacent switches 2, 3, 4, and 5 is low.
　出力部４０は、地絡事故予兆判定手段５１と短絡事故予兆判定手段５２と断線事故予兆判定手段５３との何れかが事故又は事故予兆と判定したとき、事故内容を表示したり、ネットワークを介して出力したりする。 When any one of the ground fault sign determining means 51, the short circuit accident sign determining means 52, and the disconnection accident sign determining means 53 determines an accident or an accident sign, the output unit 40 displays the accident content or via a network. And output.
（変形例）
　本発明は前記した実施形態に限定されるものではなく、例えば以下のような種々の変形が可能である。
（１）前記第５実施形態の電力系統監視装置１０２の出力部４０は、表示画面２００（図１１）に事故発生確率２１３を表示させていた。この事故発生確率２１３は、制御部５０が、相関係数の絶対値を事故確率と見なしたり、相関係数の絶対値に所定の変換式を乗算した値を事故確率としたりしていた。 (Modification example)
The present invention is not limited to the above-described embodiment, and various modifications such as the following are possible.
(1) The output unit 40 of the power system monitoring device 102 of the fifth embodiment displays the accident occurrence probability 213 on the display screen 200 (FIG. 11). In the accident occurrence probability 213, the control unit 50 regards the absolute value of the correlation coefficient as the accident probability, or the value obtained by multiplying the absolute value of the correlation coefficient by a predetermined conversion formula as the accident probability.
　ところで、電力系統の事故や予兆は、様々な要因の組み合わせとして引き起こされることがある。例えば、樹木等の接触物、雨風等の気象条件等があり、これらが組み合わされて樹木接触による地絡事故が起きる場合がある。また過去に事故が起きた箇所では、その際の事故要因が取り除かれているとしても、何らかの性能劣化が残っていて事故が起きやすくなる可能性がある。 By the way, power system accidents and signs can be caused by a combination of various factors. For example, there are contact objects such as trees, weather conditions such as rain and wind, and these may be combined to cause a ground fault due to contact with trees. Further, in a place where an accident has occurred in the past, even if the cause of the accident at that time is removed, there is a possibility that some performance deterioration remains and the accident is likely to occur.
　本実施形態の制御部５０は、計測信号に加えて、電力系統に関わる系統構成、過去の事故履歴、気象状況、樹木生育等の外部状況を組み合わせて判定結果を得る。例えば、複数の要因を組み合わせて複合要因として定量化するため確率を用いた計算が利用可能である。確率計算は、ベイズ確率（ベイズ統計）の考え方を利用できる。例えば、事前確率を用意して、事故要因の起こりやすさを示す確率値を掛け合わせて正規化することで、複数要因を組み合わせた事後確率を算出する。 The control unit 50 of the present embodiment obtains a determination result by combining the measurement signal and external conditions such as the system configuration related to the power system, past accident history, weather conditions, and tree growth. For example, a calculation using a probability can be used to combine a plurality of factors and quantify them as a compound factor. For probability calculation, the concept of Bayesian probability (Bayesian statistics) can be used. For example, by preparing prior probabilities and normalizing them by multiplying them by probability values indicating the likelihood of accident factors, posterior probabilities that combine multiple factors are calculated.
　制御部５０は、このように換算して得られた確率を事前確率として設定する。そして、制御部５０は、電力に関わる外部状況を条件付確率として設定し、ベイズの式を用いて事後確率を算出する。複数の条件に基づく確率や時間経過に伴う確率を用いて、事前確率から事後確率を算出する手順を繰り返して確率を更新する。 The control unit 50 sets the probability obtained by conversion in this way as a prior probability. Then, the control unit 50 sets an external situation related to electric power as a conditional probability, and calculates the posterior probability using the Bayesian formula. The probability is updated by repeating the procedure of calculating the posterior probability from the prior probability using the probability based on multiple conditions and the probability with the passage of time.
（２）前記各実施形態では、二つの波形の相似性を測る尺度として相関係数を用いていたが、二乗誤差等を用いることもできる。二乗誤差は、二つの信号の差分を二乗して、ある区間に渡って累積して算出する実数値であり、波形が相似であるときに最小値をとる。相関係数や二乗誤差は、ある程度の時間幅に渡る累積計算をすることから積分計算と同様の性質を持つことになり、ノイズの影響を受けにくく、微小信号であっても安定した計算結果が得られる特徴がある。相似性の尺度として二つの計測信号の二乗誤差を利用する場合は、二乗誤差は正の実数値になるので波形の反転を反映しない。このため、波形の反転を判定するときには、例えば、図４を用いて説明したように、相関係数の符号を用いる必要がある。 (2) In each of the above embodiments, the correlation coefficient is used as a scale for measuring the similarity between the two waveforms, but a square error or the like can also be used. The square error is a real value calculated by squaring the difference between two signals and accumulating over a certain interval, and takes the minimum value when the waveforms are similar. The correlation coefficient and squared error have the same properties as the integral calculation because the cumulative calculation is performed over a certain time width, and they are not easily affected by noise, and stable calculation results can be obtained even for minute signals. There are features that can be obtained. When the square error of two measurement signals is used as a measure of similarity, the square error is a positive real value and does not reflect the inversion of the waveform. Therefore, when determining the inversion of the waveform, for example, as described with reference to FIG. 4, it is necessary to use the sign of the correlation coefficient.
（３）また、何らかの信号変換（例えば、周波数成分等に変換するフーリエ変換）をしてから相似性を算出しても構わない。例えば、フーリエ変換を用いて、２つの計測信号（時系列信号）を周波数成分に変換して、両者の周波数成分を比較する。そして、高調波の次数ごとの周波数成分の差分を二乗誤差として算出する。ここでも、二乗誤差は正の実数値になるので波形の反転を反映しないので、例えば、図４を用いて説明したように、相関係数の符号を用いる。 (3) Further, the similarity may be calculated after performing some kind of signal conversion (for example, Fourier transform for converting into a frequency component or the like). For example, using the Fourier transform, two measurement signals (time series signals) are converted into frequency components, and the frequency components of both are compared. Then, the difference of the frequency component for each order of the harmonic is calculated as the squared error. Again, since the squared error is a positive real value, it does not reflect the inversion of the waveform. Therefore, for example, as described with reference to FIG. 4, the code of the correlation coefficient is used.
　　１，８　変圧器（電源）
　　２，３，４，５　開閉器
　　６　負荷
　　７　保護リレー
　１０　受信手段（第１の手段）
　２０　相似性算出手段（第２の手段）
　２１　スケール変換手段
　２２　類似度算出手段
　２３　最大類似度判定手段
　２４　変数変更手段
　２５　相関係数算出手段
　３０　電気現象判定手段（第３の手段）
　３１　地絡判定手段
　３２　短絡判定手段
　３３　断線判定手段
　４０　出力部
　５０　制御部
　５１　地絡事故予兆判定手段
　５２　短絡事故予兆判定手段
　５３　断線事故予兆判定手段
１００，１０１，１０５　電力系統監視装置
１０２　電力系統監視装置（サーバ）
１０３　電力系統監視装置（子局）
１０４　拠点サーバ 1,8 Transformer (power supply)
2, 3, 4, 5 Switch 6 Load 7 Protection relay 10 Receiving means (first means)
20 Similarity calculation means (second means)
21 Scale conversion means 22 Similarity calculation means 23 Maximum similarity determination means 24 Variable change means 25 Correlation coefficient calculation means 30 Electrical phenomenon determination means (third means)
31 Ground fault determination means 32 Short circuit determination means 33 Disconnection determination means 40 Output unit 50 Control unit 51 Ground fault sign determination means 52 Short circuit accident sign determination means 53 Disconnection accident sign determination means 100, 101, 105 Power system monitoring device 102 Power system Monitoring device (server)
103 Power system monitoring device (slave station)
104 base server

Claims (17)

  1. 　電力系統の事故又は事故予兆を検出する電力系統監視装置であって、
    　前記電力系統の電圧電流波形を計測した計測信号を、複数の計測点から受信する第１の手段と、
    　複数の前記電圧電流波形の相似性を算出する第２の手段と、
    　前記相似性を用いて、前記電力系統で発生している電気現象を判定する第３の手段と、
    を備えることを特徴とする電力系統監視装置。     A power system monitoring device that detects accidents or signs of accidents in the power system.
    A first means for receiving a measurement signal obtained by measuring a voltage / current waveform of the power system from a plurality of measurement points,
    A second means for calculating the similarity of the plurality of voltage / current waveforms, and
    A third means for determining an electrical phenomenon occurring in the power system using the similarity, and
    A power system monitoring device characterized by being equipped with.
  2. 　請求項１に記載の電力系統監視装置であって、
    　前記第３の手段は、前記相似性の高低によって、正常状態と事故予兆との何れかに判定する
    ことを特徴とする電力系統監視装置。     The power system monitoring device according to claim 1.
    The third means is a power system monitoring device, characterized in that it determines either a normal state or an accident sign based on the level of similarity.
  3. 　請求項１の電力系統監視装置であって、
    　前記第１の手段は、隣接する２箇所の計測点に流れる零相電流の計測波形を受信するものであり、
    　前記第２の手段は、２つの前記零相電流の間の相関係数を演算し、
    　前記第３の手段は、前記相関係数が負の値であって、その絶対値が大きいときに、前記２箇所の測定点の中間地点で地絡事故又は地絡事故の予兆と判定し、その絶対値が小さいときに正常状態であると判定する
    ことを特徴とする電力系統監視装置。     The power system monitoring device according to claim 1.
    The first means receives the measurement waveform of the zero-phase current flowing through two adjacent measurement points.
    The second means calculates the correlation coefficient between the two zero-phase currents and
    When the correlation coefficient is a negative value and the absolute value is large, the third means determines that a ground fault or a sign of a ground fault occurs at an intermediate point between the two measurement points. A power system monitoring device characterized in that it is determined to be in a normal state when its absolute value is small.
  4. 　請求項１の電力系統監視装置であって、
    　前記第１の手段は、各相の相電圧波形を受信するものであり、
    　前記第２の手段は、異なる相の前記相電圧波形の間の相関係数を演算し、
    　前記第３の手段は、何れかの前記相関係数の絶対値が大きいときに、電力系統の短絡事故又は短絡事故の予兆と判定し、その絶対値が小さいときに正常状態であると判定する
    ことを特徴とする電力系統監視装置。     The power system monitoring device according to claim 1.
    The first means receives the phase voltage waveform of each phase.
    The second means calculates the correlation coefficient between the phase voltage waveforms of different phases.
    The third means determines that when the absolute value of any of the correlation coefficients is large, it is a sign of a short-circuit accident or a short-circuit accident in the power system, and when the absolute value is small, it is determined to be in a normal state. A power system monitoring device characterized by this.
  5. 　請求項１の電力系統監視装置であって、
    　前記第１の手段は、開閉器の電源側及び負荷側に流れる各相の相電圧波形を受信するものであり、
    　前記第２の手段は、前記電源側及び前記負荷側の前記相電圧波形の間の相関係数を演算し、
    　前記第３の手段は、前記相関係数の絶対値が小さいときに、電力系統の断線事故又は断線事故の予兆と判定し、その絶対値が大きいときに正常状態であると判定する
    ことを特徴とする電力系統監視装置。     The power system monitoring device according to claim 1.
    The first means receives the phase voltage waveform of each phase flowing to the power supply side and the load side of the switch.
    The second means calculates the correlation coefficient between the phase voltage waveforms on the power supply side and the load side.
    The third means is characterized in that when the absolute value of the correlation coefficient is small, it is determined to be a sign of a power system disconnection accident or a disconnection accident, and when the absolute value is large, it is determined to be in a normal state. Power system monitoring device.
  6. 　請求項３乃至請求項５の何れか一項に記載の電力系統監視装置は、
    　計測波形の相関係数を確率に換算する確率換算手段をさらに備える
    ことを特徴とする電力系統監視装置。     The power system monitoring device according to any one of claims 3 to 5.
    A power system monitoring device characterized by further including a probability conversion means for converting the correlation coefficient of the measured waveform into a probability.
  7. 　請求項１の電力系統監視装置であって、
    　前記第２の手段は、計測波形の二乗誤差を算出する
    ことを特徴とする電力系統監視装置。     The power system monitoring device according to claim 1.
    The second means is a power system monitoring device characterized in that a square error of a measured waveform is calculated.
  8. 　請求項１の電力系統監視装置であって、
    　前記第２の手段は、位相と波高をスケール変換する手段である
    ことを特徴とする電力系統監視装置。     The power system monitoring device according to claim 1.
    The second means is a power system monitoring device characterized in that it is a means for scale-converting a phase and a wave height.
  9. 　請求項１に記載の電力系統監視装置であって、
    　前記第１の手段は、複数の前記計測点からの計測信号を受信し、
    　前記第２の手段は、隣接する計測点で計測した前記電圧電流波形の相似性を算出する
    ことを特徴とする電力系統監視装置。     The power system monitoring device according to claim 1.
    The first means receives measurement signals from the plurality of measurement points and receives measurement signals from the plurality of measurement points.
    The second means is a power system monitoring device characterized by calculating the similarity of the voltage / current waveforms measured at adjacent measurement points.
  10. 　請求項１に記載の電力系統監視装置であって、
    　前記第１の手段は、自装置が計測した計測信号と他の計測機器が計測した計測信号とを相互にデータ交換するデータ伝送手段をさらに備え、
    　前記第２の手段は、自装置が計測した前記電圧電流波形と隣接する計測機器が計測した前記電圧電流波形の相似性を算出する
    ことを特徴とする電力系統監視装置。     The power system monitoring device according to claim 1.
    The first means further includes a data transmission means for exchanging data between the measurement signal measured by the own device and the measurement signal measured by another measuring device.
    The second means is a power system monitoring device for calculating the similarity between the voltage / current waveform measured by the own device and the voltage / current waveform measured by an adjacent measuring device.
  11. 　請求項１乃至請求項１０の何れか一項に記載の電力系統監視装置であって、
    　前記電気現象の判定結果を出力する出力手段をさらに備える
    ことを特徴とする電力系統監視装置。     The power system monitoring device according to any one of claims 1 to 10.
    A power system monitoring device further comprising an output means for outputting a determination result of the electric phenomenon.
  12. 　電力系統の事故予兆を検出する電力系統監視装置であって、
    　前記電力系統の複数の計測点で電圧電流波形を計測した計測信号を受信する受信手段と、
    　前記電圧電流波形を用いて、地絡事故、短絡事故、断線事故の何れの事故予兆かを判定する判定手段と、
    を備えることを特徴とする電力系統監視装置。     It is a power system monitoring device that detects signs of accidents in the power system.
    A receiving means for receiving a measurement signal obtained by measuring a voltage / current waveform at a plurality of measurement points of the power system.
    Using the voltage / current waveform, a determination means for determining which of a ground fault accident, a short circuit accident, and a disconnection accident is a sign of an accident,
    A power system monitoring device characterized by being equipped with.
  13. 　電力系統の事故予兆を検出する電力系統監視装置であって、
    　前記電力系統の複数の計測点で電圧電流波形を計測した計測信号を受信する受信手段と、
    　前記電圧電流波形を用いて、地絡事故、短絡事故、断線事故の何れの事故予兆が何れの相で起きたかを判定する判定手段と、
    を備えることを特徴とする電力系統監視装置。     It is a power system monitoring device that detects signs of accidents in the power system.
    A receiving means for receiving a measurement signal obtained by measuring a voltage / current waveform at a plurality of measurement points of the power system.
    Using the voltage / current waveform, a determination means for determining which phase of the accident sign of a ground fault accident, a short circuit accident, or a disconnection accident occurred, and
    A power system monitoring device characterized by being equipped with.
  14. 　請求項１２又は請求項１３に記載の電力系統監視装置であって、
    　前記判定手段は、複数の前記電圧電流波形の相似性を算出する相似性算出手段と、
    　前記相似性を用いて、事故の可能性の大小を判定する
    ことを特徴とする電力系統監視装置。     The power system monitoring device according to claim 12 or 13.
    The determination means includes a similarity calculation means for calculating the similarity of a plurality of the voltage and current waveforms, and a similarity calculation means.
    A power system monitoring device characterized in that the magnitude of the possibility of an accident is determined by using the similarity.
  15. 　請求項１２乃至請求項１４の何れか一項に記載の電力系統監視装置であって、
    　前記何れの事故予兆、何れの相であるかの判定結果を出力する出力手段をさらに備える
    ことを特徴とする電力系統監視装置。     The power system monitoring device according to any one of claims 12 to 14.
    A power system monitoring device further comprising an output means for outputting a determination result of which of the accident signs and which phase it is in.
  16. 　電力系統の事故又は事故予兆を検出する電力系統監視装置の制御部が実行する電力系統監視方法であって、
    　前記電力系統の電圧電流波形を計測した計測信号を、複数の計測点から受信する第１ステップと、
    　複数の前記電圧電流波形の相似性を算出する第２ステップと、
    　前記相似性を用いて、前記電力系統で発生している電気現象を判定する第３ステップと、
    を実行することを特徴とする電力系統監視方法。     A power system monitoring method executed by the control unit of a power system monitoring device that detects an accident or a sign of an accident in the power system.
    The first step of receiving the measurement signal obtained by measuring the voltage / current waveform of the power system from a plurality of measurement points, and
    The second step of calculating the similarity of the plurality of voltage and current waveforms, and
    Using the similarity, the third step of determining the electrical phenomenon occurring in the power system and
    A power system monitoring method characterized by executing.
  17. 　電力系統の事故又は事故予兆を検出する電力系統監視装置の制御部に実行させる電力系統監視プログラムであって、
    　前記電力系統の電圧電流波形を計測した計測信号を、複数の計測点から受信する第１ステップと、
    　複数の前記電圧電流波形の相似性を算出する第２ステップと、
    　前記相似性を用いて、前記電力系統で発生している電気現象を判定する第３ステップと、
    を実行させることを特徴とする電力系統監視プログラム。
          A power system monitoring program that is executed by the control unit of a power system monitoring device that detects an accident or a sign of an accident in the power system.
    The first step of receiving the measurement signal obtained by measuring the voltage / current waveform of the power system from a plurality of measurement points, and
    The second step of calculating the similarity of the plurality of voltage and current waveforms, and
    Using the similarity, the third step of determining the electrical phenomenon occurring in the power system and
    A power system monitoring program characterized by executing.
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