JP3899730B2 - Fault location method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a failure point locating method for locating a failure point using voltages and currents collected by a plurality of data collection devices on a transmission and distribution line.
[0002]
[Prior art]
As technology for fault location of transmission and distribution lines, use the voltage / current obtained by means of collecting electricity such as CT / PT at one or more substations, paying attention to the principle of distance relay and the shunt ratio of fault current Those using the fault location method have been put into practical use (Japanese Patent Publication No. 6-68535, Japanese Patent Laid-Open No. 8-122395, etc.). Also, a method focusing on the arrival time difference at each end of the transmission line due to the occurrence of a failure (hereinafter referred to as a surge method) or a method applying a pulse on the transmission line and focusing on the arrival time of the reflected wave (hereinafter referred to as a pulse) System) is put into practical use.
[0003]
[Problems to be solved by the invention]
The methods using the amount of electricity at each end of the transmission line disclosed in Japanese Patent Publication No. 6-68535 and Japanese Patent Laid-Open No. 8-122395 have the following problems.
An orientation method (hereinafter referred to as “one-terminal determination type”) using an electric quantity at one end of a transmission line represented by Japanese Patent Laid-Open No. 8-122395 discloses that when a plurality of power supplies and loads are branched and connected to the transmission line, Since an unknown amount is included in the current flowing through the failure point and the current flowing through the load, a basic orientation error occurs.
[0004]
JP-A-6-68535, JP-A-58-208676, and other systems that collect and determine the amount of electricity at each end of a transmission line (hereinafter referred to as multi-terminal judgment type) Since the current flowing in the terminal and the current flowing in the load become the measurement amount, there is an advantage that the orientation error is reduced compared to the one-terminal determination type.
However, there is a problem that a long-distance communication infrastructure such as a dedicated line facility of an electric power company is required as a communication means for collecting the collected electricity amount at each terminal of the electric wire in one place. In addition, when a part of the transmission line is a customer, the data collection facility may not be installed due to the convenience of the customer. The fact that there is an end that cannot collect the amount of electricity means that the current flowing into and out of that end is an unknown amount, which greatly affects the fault location accuracy. Furthermore, in the transmission line including a large number of branches, the orientation is complicated, and there is also a problem that the grounding current generated in the middle of the electric wire cannot be detected at each end and the orientation accuracy is lowered.
[0005]
In addition, the surge method and the pulse method generally require a larger equipment scale for fault location as compared to the one-terminal determination type and the multi-terminal determination type. Furthermore, since there are many reflection points of surges and pulses in the multi-terminal transmission / distribution line, it is difficult to accurately determine the fault point.
[0006]
Therefore, the present invention makes use of the advantages of the multi-terminal determination type by using the amount of electricity collected synchronously from a plurality of power supply ends of the transmission / distribution line and the intermediate point of the transmission / distribution line, and also a large-scale and long-distance communication facility. Therefore, an object of the present invention is to provide a failure point locating method capable of performing highly accurate locating without using a transmission means or the like.
[0007]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the invention according to claim 1 is arranged such that a data collecting device capable of collecting electric power in synchronism is arranged at all power supply terminals of the transmission / distribution line, and at one power supply terminal when a failure occurs. Using the collected voltage and current, the current collected at all other power terminals, and the known transmission and distribution line impedance, the fault phase current collected at all power terminals of the voltage on the transmission and distribution lines The point where the component orthogonal to the sum vector is minimum (almost zero) is determined as the failure point.
[0009]
The invention according to claim 2 arranges a plurality of data collection devices that can collect electricity in synchronism with all the power supply terminals on the transmission and distribution lines and in the middle of the transmission and distribution lines, and collects at one power supply terminal when a failure occurs. The voltage distribution on the transmission / distribution line is obtained using the collected voltage and current, the current collected in the middle of the transmission / distribution line, and the known transmission / distribution line impedance. The point where the component orthogonal to the vector of the sum of the fault phase currents collected in (1) is minimized is determined as the fault point. That is, in the present invention, unlike the invention of claim 1, since the current amount at the midpoint of the transmission / distribution line is also used, the voltage calculation accuracy at each point on the transmission / distribution line can be improved. This contributes to higher accuracy of the orientation process for searching for a point where the minimum is.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
First, FIG. 1 is a diagram showing an installation example of a data collection device in an embodiment of the present invention. In FIG. 1, 100 is a substation (A end), 200 is a substation (B end), 300 is a substation (C end), 401 to 407 are data collection devices, and 501 and 502 are transmission and distribution lines.
All of the above data collection devices have the same configuration, and the size of the data collection devices is a compact size that can be installed on a steel tower or power pole at an arbitrary point of a substation or transmission / distribution line. Here, the installation point of the data collection device is not limited to the illustrated example, but in the invention of claim 1, at least all the power supply terminals, in the invention of claim 2, every predetermined interval on the transmission and distribution line, In invention of Claim 3, it arrange | positions in the arbitrary positions on an at least 1 power supply end and a power transmission and distribution line.
[0011]
The data collection devices 401 to 407 detect voltages and currents from electric transmission / distribution lines by means of electric quantity detection means such as PT / CT, take in them, convert these analog electric quantities into digital values, and convert the amplitude value / effective value / position. Calculates various electrical quantities such as phase difference, impedance, and change width. These amounts of electricity are stored in a memory as needed, and are added to the amount of electricity transmitted from the data collection device in the previous section and transmitted to the data collection device in the next section. In FIG. 1, all the collected electricity is collected in the data collection device 401 of the substation 100 and is transmitted to, for example, a fault location device using the hardware of a digital relay.
As a means for transmission between data collection devices, public wireless telephone communications such as mobile phones and PHS, or low-power wireless communications can be used, thereby simplifying communication facilities and transmission means and saving power. Can do.
[0012]
The operation of collecting the amount of electricity by the data collection device is activated by a preset cycle, an operation input by an operator, or a command from a remote location.
In addition, the data collection device has a fault detection relay function and overcurrent detection function such as overcurrent relay, variable width overcurrent relay, overvoltage relay, undervoltage relay, etc., and transmits electric quantity only when fault is detected or overcurrent detection It may be possible to collect and transmit electricity by supplying power only occasionally. As a result, it is possible to save power, reduce transmission capacity, reduce the influence of noise on the surrounding environment, and the like.
[0013]
Further, each of the data collection devices 401 to 407 may be provided with a clock function using a GPS (global positioning system). In the current GPS, highly accurate time data is transmitted from an artificial satellite at a cycle of 1 second. Therefore, the data collection devices 401 to 407 on the transmission and distribution lines detect this time data, so that all the collection devices can acquire the same time information.
[0014]
If the data collection devices 401 to 407 add the time data to the electricity amount at the time of collecting the electricity amount and collect the electricity amount with the collection time in one place by the GPS, the timing difference between the collected data at the aggregation destination That is, the time difference can be corrected. For example, when the data collected by the first and second data collection devices are data collected at time (t ₁ , t ₂ ), the time difference (Δt = t ₂ −t ₁ ) and the electric quantity The phase correction (addition) of 2πfΔt [rad] (π is the circumference) is performed on the electric quantity of the second data collection device using the frequency f of the second data collection device. The amount of electricity can be handled as if it was collected at time t ₁ .
Since such a technique is established by, for example, Japanese Patent Application Laid-Open No. 6-338037, etc., if these techniques are used, vector phase synchronization of electric quantity among a plurality of data collection devices becomes possible, and a multi-terminal Fault location using electric quantity can be realized with high accuracy.
[0015]
In FIG. 1, the data collection device of the substation 100 (A end) collects voltage and current, and the data collection devices of the substation 200 (B end) and the substation 300 (C end) receive only current. Shall be collected. Of the B end and C end, those that are not power supply ends (C end in the example of FIG. 1) omit the installation of the data collection device.
Now, as shown in FIG. 2, the operation of this embodiment will be described on the assumption of a two-terminal transmission / distribution line of a single-end power supply or a double-end power supply.
[0016]
2A shows a case of a one-end power source having a power source 601 at one end and a load 800 at the other end, and FIG. 2B shows a case of a both-end power source having an S power source 701 at one end and an R power source 702 at the other end. is there. Reference numerals 411 to 414 denote the data collection devices described above.
When a failure occurs in the transmission / distribution line, as shown in FIGS. 2A and 2B, a failure current flows from each power supply end toward the failure point in addition to the normal load current.
[0017]
Examples of voltage distribution at each point of the transmission / distribution line at the time of failure are shown in FIGS.
FIG. 4A shows a voltage distribution at the time of one-end power supply as shown in FIG. 2A. From the power supply end to the failure point, the current I is large and the voltage is determined by VZ · I (Z is the line impedance). The change is also big. Further, from the failure point to the load end, I is only the load current, and the voltage change is small.
FIG. 4B shows a voltage distribution at the time of power supply at both ends as shown in FIG. 2B. The voltage distribution is symmetrical on both ends with the failure point as the center.
[0018]
FIG. 5 (A) shows a vector of the sum of the fault phase currents at both ends of the power supply, that is, the distribution of voltage components Re {V} in phase with the combined current (polar current) at both ends, and FIG. The distribution of the component Im {V} is shown. Here, the voltage vector V = Re {V} + Im {V} on the transmission and distribution line.
From these figures, the voltage component Re {V} changes approximately by the voltage corresponding to the failure point resistance value × I, and the voltage component Im {V} changes approximately by the voltage corresponding to the reactance value × I of the wire. Become.
[0019]
In the conventional technique such as Japanese Patent Application Laid-Open No. 8-122395, the failure point determination based on the impedance calculation performed at one terminal voltage / current is a voltage component at each point where the voltage component orthogonal to the combined current at both ends is the failure point. In FIG. 2, a point that becomes almost 0 [V] is used, and a point that becomes 0 [V] is regarded as a failure point. This occurs because the residual voltage at the fault point is the product of the fault point resistance (substantially pure resistance) and the fault current at the fault point that flows through it. The component uses the feature of 0 [V]. Since the fault current at the fault point is an unknown quantity, it was a major technical issue to determine the positioning accuracy based on whether the current in phase with the fault current at the fault point was obtained based on the current detected at the end of the transmission and distribution line. .
In the prior art, as a method for obtaining a current having the same phase as the fault current at the fault point, a fault phase current, a zero phase / reverse phase current based on the target coordinate method, an α circuit current based on the α-β-O method, or the like is used. Have been proposed, each with its own characteristics.
[0020]
However, both methods simulate the fault current that flows from the power source (one power supply end of the transmission and distribution line) behind the fault point location device to the fault point, whereas the actual fault current is shown in Fig. 2 ( As shown in the current image of the power supply at both ends B), the current is summed from all power supply terminals. For this reason, none of the prior arts can simulate fault currents from other power supply terminals, and if there is a phase difference in the fault currents from each power supply terminal, the fault is caused only by the amount of electricity at one end of the transmission and distribution lines. It is difficult to obtain a current having the same phase as the point failure current, and a fault location error is caused by the phase difference.
[0021]
Therefore, the embodiment of the invention described in claim 1 is characterized in that the time-synchronized currents of all the power supply terminals are directly obtained, and the resultant current (vector of the sum of the currents) is used as the polarity current. For example, in the example of FIG. 1, when the substations 100 and 200 are both power supply terminals, the data collection device 401 in the substation 100 collects voltage and current, and the data collection device 401 in the substation 200 has only current. Are collected and transmitted to the data collection device 401 and transmitted to the fault location device. 2B, the data collection device 411 at the end of the S power supply 701 collects voltage / current, and the data collection device 414 at the end of the R power supply 702 collects only current.
As described above, it is possible to synchronize the phase of the collected electricity by each data collection device using the GPS clock function, so even if there is a phase difference in the fault current collected by the data collection devices 411 and 414 The phase difference can be made almost zero. And fault location is performed as follows using these electric quantities.
[0022]
As a specific failure point locating method, a conventional failure point locating method based on impedance calculation performed with a one-terminal voltage / current is used.
That is, it is a component of the voltage vector V collected by the data collection device 411 at the end of the S power supply 701 in FIG. 2 and is combined into a combined current vector at both ends (a vector of the sum of collected currents phase-synchronized by the data collection devices 411 and 414). The orthogonal voltage component Im {V} becomes almost zero at the failure point as shown in FIG. Therefore, the voltage drop due to the product of the current (fault current) collected by the data collection device 411 at the end of the S power supply 701 and the transmission / distribution line reactance value (proportional to the length of the transmission / distribution line) is the voltage component Im {V }, It is possible to determine the point as a failure point.
As a result, it is possible to locate the fault point with high accuracy by apparently eliminating the phase difference of the fault current from each power supply end.
[0023]
Next, a reference embodiment of the present invention will be described.
FIG. 3 shows a vector example of each current collected by each collecting device in the system of FIG. At the time of one-end power supply (FIG. 2 (A), FIG. 3 (A)), between the power supply and the failure point is almost uniform (failure current + load current), and this (failure current + load current) is data collection. Collected by devices 411, 412. Between the failure point and the load end is only the load current, and this load current is collected by the data collection devices 413 and 414. That is, there is a sudden change in the current value before and after the failure point.
In the case of power supply at both ends (FIGS. 2B and 3B), the data collection devices 411 and 412 collect the fault current from the S power supply 701, and the data collection devices 413 and 414 receive from the R power supply 702. Collect fault current. Although the absolute values of these current vectors are substantially equal in FIG. 3B, the difference between the current vectors is large.
[0024]
View of the above problems, in this reference embodiment, by synchronizing the current amount of each point by the arrangement data collection device to any point on the transmission and distribution lines collected, current vector adjacent to the data collection device collects respectively , And the fault point is determined as if there is a fault point between adjacent data collectors where the difference between the two exceeds a certain value (that is, the collected current vector suddenly changes between adjacent data collectors). Is.
Thereby, in the example of FIG. 2 and FIG. 3, the area between the data collection devices 412 and 413 is determined as a failure point.
According to the above method , even in a system having a plurality of power supplies, since there is a sudden change in the current vector across the failure point, the failure point can be reliably determined as in the one-end system.
[0025]
The above method has an advantage that fault location can be performed only with current data at the time of failure. Moreover, it is a simple principle which only looks at the difference between the current vectors collected by each data collection device on the transmission / distribution line, and the failure mode (simple failure / multiple failure at the same point / multiple failure at different points) does not matter. Furthermore, there is a feature that there is no setting of the impedance settling value and these settling errors do not exist, and since the positioning error is determined by the installation interval of the data collecting device, a short distance (for example, every tower) on the transmission and distribution line ( If a data collection device can be installed at intervals of several hundred meters, high-precision orientation can be achieved.
[0026]
Next, an embodiment of the invention described in claim 2 will be described. First, the above-described orientation method has two problems.
One is a physical / economic reason. When the data collection device cannot be installed at a short interval, the orientation error becomes larger as the installation interval becomes longer.
The other is a case where the fault current is small and the current vector difference between adjacent data collection devices is very small. In this case, for example, fault location by a conventional technique such as Japanese Patent Publication No. 6-68535 can be considered. However, in these prior arts, a fault current is diverted to a branch line connected to an end without a data collection device, particularly a consumer (load end and power supply end) where the data collection device cannot be installed due to circumstances, or a fault current from the end. The inflow becomes a factor of orientation error.
In addition, since the current at the end does not include the charging current due to the ground capacity of the electric wire, this also becomes a cause of the orientation error.
[0027]
Therefore, in the invention described in claim 2 , the voltage at each point of the transmission / distribution line as in the prior art is obtained from the voltage / current of one power supply end and the known impedance of the transmission / distribution line, and further, the current at the midpoint of the transmission / distribution line. Calculate the distribution. It goes without saying that the phase synchronization of each collected electric quantity is also taken here. In particular, in the present embodiment, the current at the end is not used unconditionally as the current value, but the amount of current collected by the data collection device is used in a section in the middle of the transmission / distribution line beyond the data collection device installation point. Thus, since the charging current is included in the current collected by the data collection device in the middle of the transmission / distribution line, errors due to the charging current can be reduced. Further, even in a branch line having no data collection device at the end, it is easy to detect a fault current that is shunted by installing at least one data collection device between the branch point and the end.
[0028]
In the present embodiment, by using the collected current in the collecting device as described above, the charging current and the shunt failure current can be detected, and the voltage distribution on the transmission and distribution line can be calculated more accurately. If the voltage distribution on the transmission / distribution line is accurately obtained in this way, the point where the voltage component orthogonal to the polarity current of the voltage on the transmission / distribution line becomes almost zero, that is, the fault location is determined as in the embodiment of claim 1. In addition, it can be easily realized by impedance calculation using the reactance of the transmission and distribution lines.
[0029]
【The invention's effect】
As described above, according to the present invention, by using the voltage and current collected in synchronization from a plurality of power supply ends of the transmission and distribution lines and the midpoint of the transmission and distribution lines, taking advantage of the conventional multi-terminal determination type, In addition, the failure point can be determined with high accuracy without using a large-scale and long-distance communication facility such as a dedicated line or transmission means.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating an installation example of a data collection device according to an embodiment of the present invention.
FIG. 2 is an explanatory diagram of current distribution at the time of one-end power supply and both-end power supply.
FIG. 3 is an explanatory diagram of a current vector in FIG. 2;
FIG. 4 is an explanatory diagram of voltage distribution at the time of one-end power supply and at both-end power supply.
FIG. 5 is an explanatory diagram of voltage distribution in a power supply system at both ends.
[Explanation of symbols]
100, 200, 300 Substations 401, 402, 403, 404, 405, 406, 407, 411, 412, 413, 414 Data collection devices 501, 502 Transmission and distribution lines 601, 701, 702 Power supply 800 Load

Claims (2)

  Data collection devices that can collect the amount of electricity in synchronization are arranged at all power supply terminals of the transmission and distribution lines, and the voltage and current collected at one power supply terminal at the time of failure and at all other power supply terminals Using the collected current and the known transmission / distribution line impedance, the point where the component of the voltage on the transmission / distribution line that is orthogonal to the sum vector of the sum of the fault phase currents collected at all the power supply terminals is failed. A fault locating method characterized by locating as a point. Multiple data collection devices that can collect and collect the amount of electricity synchronized in the middle of all power supply terminals on the transmission and distribution lines, and the voltage and current collected at one power supply terminal when a failure occurs , and the transmission and distribution Using the current collected in the middle of the wire and the known transmission / distribution line impedance, the voltage distribution on the transmission / distribution line is obtained, and the fault phase current collected at all power terminals of the voltage on the transmission / distribution line is obtained. A failure point locating method characterized by locating a point where the component orthogonal to the sum vector is minimum as a failure point.

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