WO2020053918A1 - 過電流継電器 - Google Patents
過電流継電器 Download PDFInfo
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- WO2020053918A1 WO2020053918A1 PCT/JP2018/033370 JP2018033370W WO2020053918A1 WO 2020053918 A1 WO2020053918 A1 WO 2020053918A1 JP 2018033370 W JP2018033370 W JP 2018033370W WO 2020053918 A1 WO2020053918 A1 WO 2020053918A1
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- overcurrent
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/08—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess current
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H3/00—Mechanisms for operating contacts
- H01H3/02—Operating parts, i.e. for operating driving mechanism by a mechanical force external to the switch
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H33/00—High-tension or heavy-current switches with arc-extinguishing or arc-preventing means
- H01H33/02—Details
- H01H33/59—Circuit arrangements not adapted to a particular application of the switch and not otherwise provided for, e.g. for ensuring operation of the switch at a predetermined point in the ac cycle
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/02—Details
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/165—Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/175—Indicating the instants of passage of current or voltage through a given value, e.g. passage through zero
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/02—Details
- H02H3/06—Details with automatic reconnection
Definitions
- the present disclosure relates to an overcurrent relay.
- the overcurrent relay detects a system fault and outputs an operation.
- a circuit breaker (CB: Circuit Breaker) provided in the power system is opened to eliminate the system accident.
- the overcurrent relay is configured to output a return when the secondary current becomes smaller than the set value (ie, to turn off the operation output).
- Patent Document 1 discloses an overcurrent relay including a first overcurrent determination unit and a second overcurrent determination unit.
- the first overcurrent determination unit makes a return determination by comparing an effective value calculated using current data for a predetermined period with a first set value.
- the second overcurrent determination unit returns by comparing an effective value calculated using current data of a period shorter than a predetermined period with a second set value lower than the first set value. Make a decision.
- the overcurrent relay generates a return output at an earlier timing among the return determination results of each of the first overcurrent determination unit and the second overcurrent determination unit.
- the second set value is changed to a value lower than the first set value in synchronization with the output timing of the operation output, and the second set value is changed in synchronization with the output timing of the return output.
- the second set value is changed to a value higher than the first set value.
- the error of the effective value calculation result by the second overcurrent determination unit greatly affects the accuracy of the return determination.
- An object of an aspect of the present disclosure is to provide an overcurrent relay capable of achieving both appropriate recovery and faster recovery time.
- An overcurrent relay includes an overcurrent detection unit that detects an overcurrent by comparing an effective value of an input current input from a power system with a set value, and a drop that detects a decrease in an effective value.
- a detection unit an output control unit that generates an operation output and a return output based on a detection result of the overcurrent detection unit, a detection result of the drop detection unit, and a predetermined condition regarding a current waveform of the input current.
- the output control unit generates a return output regardless of the detection result of the overcurrent detection unit when a decrease in the effective value is detected and a predetermined condition is satisfied.
- An overcurrent relay includes: a first overcurrent detection unit including a first digital filter that generates first current data that extracts a rated frequency component of an input current input from a power system; A second overcurrent detection unit including a second digital filter that has a filter characteristic faster than the filter and generates second current data in which a rated frequency component of the input current is extracted.
- the first overcurrent detection unit outputs a first detection result of the overcurrent by comparing the first effective value calculated using the first current data in the first period with the first set value.
- the second overcurrent detection unit compares a second effective value calculated using the second current data of the second period shorter than the first period with a second set value larger than the first set value.
- the overcurrent relay outputs an operation output and a return output based on the decrease detection unit that detects that the first effective value has decreased, the first to third detection results, and the detection result of the decrease detection unit.
- a control unit When a decrease in the first effective value is detected, the output control unit outputs a first detection result indicating that the overcurrent has not been detected and a third detection result indicating that the overcurrent has not been detected.
- the return output is generated at the earlier output timing.
- FIG. 3 is a diagram illustrating an example of a hardware configuration of an overcurrent relay.
- FIG. 3 is a block diagram showing an example of a functional configuration of the overcurrent relay according to the first embodiment.
- FIG. 4 is a schematic diagram showing an input current and an effective value from the occurrence of a failure until the breaker is opened.
- FIG. 4 is a diagram for describing a method of detecting a decrease in an effective value according to the first embodiment.
- FIG. 3 is a diagram for illustrating a zero-cross detection method according to the first embodiment.
- FIG. 5 shows an example of an operation in the overcurrent relay according to the first embodiment.
- FIG. 13 is a block diagram showing an example of a functional configuration of an overcurrent relay according to a second embodiment.
- FIG. 13 is a block diagram showing an example of a functional configuration of a DC determination unit according to a second embodiment.
- FIG. 13 is a diagram showing an example of an operation in the overcurrent relay according to the second embodiment.
- FIG. 14 is a block diagram showing an example of a functional configuration of an overcurrent relay according to a third embodiment.
- FIG. 13 is a diagram showing an example of an operation in the overcurrent relay according to the third embodiment.
- FIG. 1 is a diagram schematically illustrating an example of the entire configuration of a power system in which a protection relay system is installed.
- an electric wire 1 is connected to buses 2 and 3. Further, the electric wire 1 is provided with circuit breakers 4, 5, 6 and a current transformer 7.
- the circuit breakers 4, 5, 6 and the current transformer 7 are provided on each phase electric wire.
- the protection relay system 10 includes a protection relay 20 and an overcurrent relay 30.
- the protection relay 20 functions as a protection relay that detects an accident in the power system
- the overcurrent relay 30 functions as a CBF relay for preventing circuit breaker failure (CBF: Circuit Breaker Failure).
- the protection relay 20 includes a main protection relay and a back-up protection relay for a relay failure of the main protection relay.
- the CBF relay includes an overcurrent relay element for detecting that the fault current has not been interrupted due to the circuit breaker non-operation.
- the CBF relay receives a trip signal from a protection relay that detects an accident in a power system, and outputs a trip signal for opening an adjacent circuit breaker when current detection by an overcurrent relay element continues for a certain amount or more. Output.
- the protection relay 20 detects the occurrence of an accident in the power system based on the input current from the current transformer 7 provided on the electric wire 1, outputs a trip signal TR ⁇ b> 1 as an open command to the circuit breaker 4, and outputs an overcurrent relay.
- the trip signal TR2 is output to the terminal 30. Note that the trip signal output from the common digital output circuit may be branched, and the branched signal may be input to the circuit breaker 4 and the overcurrent relay 30, respectively.
- the accident determination method using the protection relay 20 is not particularly limited.
- the protection relay 20 may include, for example, a current differential relay element or a distance relay element.
- a current differential relay element a current detected by another current transformer provided on the electric wire 1 is also input to the protection relay 20.
- the voltage detected by the voltage transformer provided on the bus 2 is also input to the protection relay 20.
- the overcurrent relay 30 determines the presence or absence of a fault current based on the input current from the current transformer 7. The overcurrent relay 30 determines that the circuit breaker 4 is inoperative when the fault current is detected even after the time required to open the circuit breaker 4 has elapsed after receiving the trip signal TR2 from the protection relay 20; The trip signal TR3 is output to the peripheral circuit breakers 5 and 6. Trip signal TR3 is branched and input to circuit breakers 5 and 6, respectively. Note that the trip signals output from different digital output circuits may be input to the circuit breakers 5 and 6, respectively.
- FIG. 2 is a diagram illustrating an example of a hardware configuration of the overcurrent relay 30.
- overcurrent relay 30 includes an auxiliary transformer 51, an AD (Analog to Digital) converter 52, and an arithmetic processing unit 70.
- the overcurrent relay 30 is configured as a digital protection relay.
- the hardware configuration of the protection relay 20 is the same as the hardware configuration shown in FIG.
- the auxiliary transformer 51 takes in the input current from the current transformer 7, converts it into a voltage signal suitable for signal processing in the relay internal circuit, and outputs it.
- the AD converter 52 takes in the voltage signal output from the auxiliary transformer 51 and converts it into digital data.
- the AD converter 52 includes an analog filter, a sample and hold circuit, a multiplexer, and an AD converter.
- the analog filter removes high frequency noise components from the signal output from the auxiliary transformer 51.
- the sample hold circuit samples a signal output from the analog filter at a predetermined sampling cycle.
- the multiplexer sequentially switches the waveform signal input from the sample and hold circuit in a time series based on the timing signal input from the arithmetic processing unit 70 and inputs the signal to the AD converter.
- the A / D converter converts a signal input from the multiplexer from analog data to digital data.
- the AD converter outputs the digitally converted signal (that is, digital data) to the arithmetic processing unit 70.
- analog-digital conversion is performed at 12 sampling periods during one cycle of the electrical angle at the rated frequency (that is, 360 °). In this case, one sampling interval is a time interval corresponding to an electrical angle of 30 ° at the rated frequency.
- the arithmetic processing unit 70 includes a CPU (Central Processing Unit) 72, a ROM 73, a RAM 74, a DI (digital input) circuit 75, a DO (digital output) circuit 76, and an input interface (I / F) 77. . These are connected by a bus 71.
- CPU Central Processing Unit
- ROM Read Only Memory
- RAM Random Access Memory
- DI digital input
- DO digital output
- I / F input interface
- the CPU 72 controls the operation of the overcurrent relay 30 by reading and executing a program stored in the ROM 73 in advance.
- the ROM 73 stores various information used by the CPU 72.
- CPU 72 is, for example, a microprocessor.
- the hardware may be an FPGA (Field Programmable Gate Array) other than the CPU, an ASIC (Application Specific Integrated Circuit), a circuit having other arithmetic functions, or the like.
- the CPU 72 takes in digital data from the AD converter 52 via the bus 71.
- the CPU 72 executes a control operation using the captured digital data according to a program stored in the ROM 73.
- DO circuit 76 outputs a trip signal for opening the circuit breaker.
- the trip signal TR2 output from the DO circuit 76 of the protection relay 20 is input to the DI circuit 75 of the overcurrent relay 30.
- the input interface 77 is typically buttons or the like, and receives various setting operations from the system operator.
- FIG. 3 is a block diagram showing an example of a functional configuration of the overcurrent relay 30 according to the first embodiment.
- overcurrent relay 30 includes, as main functional components, overcurrent detection section 100, drop detection section 110, zero-crossing determination section 120, and output control section 130.
- each of these functions is realized by CPU 72 executing a program stored in ROM 73.
- a part or all of these functions may be configured to be realized by using a dedicated circuit.
- the overcurrent detection unit 100 detects an overcurrent by comparing the effective value of the input current input from the power system with the set value.
- the overcurrent detection unit 100 includes a digital filter 101, an effective value calculation unit 102, and an overcurrent determination unit 103.
- the digital filter 101 generates current data obtained by extracting the rated frequency component (that is, the fundamental wave component) of the input current. Specifically, the digital filter 101 removes the harmonic component, the DC component, and the distortion component of the input current converted into digital data by the AD converter 52, and generates current data from which a rated frequency component is extracted.
- the rated frequency component that is, the fundamental wave component
- the digital filter 101 uses, for example, data of a period T1 corresponding to a half cycle (that is, 180 °) of the electrical angle of the rated frequency. This corresponds to data of 6 sampling lengths, for example, when the number of samplings of the AD converter 52 is 12 in one cycle.
- the effective value calculation unit 102 performs an effective value calculation of the input current from which the rated frequency component has been extracted. Specifically, the effective value calculation unit 102 calculates the effective value using the current data input from the digital filter 101. The effective value calculating unit 102 calculates the effective value using, for example, the following equation (1).
- Ir (t) sqrt (
- Ir (t) indicates the effective value at time t.
- I (t) indicates a current instantaneous value of the input current from which the rated frequency component has been extracted at time t
- I (t-90) indicates a current instantaneous value 90 electrical degrees before the time t.
- I (t-180) indicates the instantaneous current value 180 electrical degrees before the time t.
- the time required to obtain data used for calculating the effective value is a time corresponding to a half cycle of the electrical angle.
- the overcurrent determination unit 103 determines whether there is an overcurrent by comparing the effective value Ir calculated by the effective value calculation unit 102 with a predetermined set value Is.
- FIG. 4 is a schematic diagram showing an input current and an effective value from the occurrence of a failure until the circuit breaker is opened.
- effective value Ir becomes equal to or greater than set value Is. Therefore, at time tx, the overcurrent determination unit 103 performs an operation determination (that is, determines that overcurrent has been detected) and outputs an output value “1”.
- overcurrent determination section 103 makes a non-operation or return determination (that is, a determination that overcurrent has not been detected), and outputs an output value “0”.
- the output value of the overcurrent determination unit 103 is the output value of the overcurrent detection unit 100.
- the output value corresponds to the detection result Dx of the overcurrent detection unit 100.
- the overcurrent detection unit 100 generates current data by extracting the rated frequency component of the input current using data of a relatively long period, calculates an effective value Ir using the current data, and calculates the effective value Ir.
- the overcurrent detection is executed using the set value Is. Therefore, the overcurrent detection unit 100 is hardly affected by harmonics and distortion waves, and does not return when a fault current occurs, and thus has high stability.
- drop detecting section 110 detects a drop in effective value Ir. Specifically, the decrease detection unit 110 detects a decrease in the effective value Ir when the decrease rate of the effective value Ir is equal to or more than the reference decrease rate.
- FIG. 5 is a diagram for explaining a method of detecting a decrease in the effective value according to the first embodiment.
- decrease detection section 110 detects a decrease in effective value Ir using the following equations (2) and (3).
- Ir (t) indicates the effective value at time t.
- Ir (t ⁇ 180) indicates an effective value 180 electrical degrees before the time t.
- the drop detecting unit 110 outputs an output value “1” when detecting a drop in the effective value Ir, and outputs an output value “0” when not detecting a drop in the effective value Ir.
- the output value corresponds to a detection result of the drop detection unit 110.
- zero-crossing determining section 120 determines whether or not a zero-crossing point of the current waveform of the input current converted into digital data by AD converting section 52 is detected.
- the zero-cross determining unit 120 includes a zero-cross detecting unit 121 and a return timer 122.
- FIG. 6 is a diagram for describing a zero-cross detection method according to the first embodiment.
- zero-crossing detecting section 121 is formed of, for example, a comparator with hysteresis, and detects a zero-crossing point of the input current by comparing with thresholds H and L set near the ground level. .
- thresholds H and L set near the ground level.
- a zero cross point is detected every half cycle.
- the return timer 122 maintains the output value for the return time Tre.
- the return time Tre is, for example, a time corresponding to / cycle (that is, an electrical angle of 240 °).
- the output of the return timer 122 is the output of the zero crossing determination unit 120.
- Zero-crossing determining section 120 outputs an output value “1” when determining that a zero-crossing point has been detected, and outputs an output value “0” when determining that a zero-crossing point has not been detected. This output value corresponds to the determination result of the zero cross determination unit 120.
- the output control unit 130 generates an operation output and a return output based on the detection result of the overcurrent detection unit 100, the detection result of the drop detection unit 110, and the determination result of the zero-cross determination unit 120.
- the output control unit 130 includes a NOT gate 131, AND gates 132 and 134, and an OR gate 133.
- the output control unit 130 generates an operation output (ie, output value “1”) and a return output (ie, output value “0”) of the overcurrent relay 30 by using these logic gates.
- NOT gate 131 performs NOT operation on the output value of drop detection section 110.
- AND gate 132 performs an AND operation on the output value of drop detection unit 110 and the output value of zero-crossing determination unit 120.
- OR gate 133 performs an OR operation on the output value of NOT gate 131 and the output value of AND gate 132.
- the AND gate 134 performs an AND operation on the output value of the overcurrent detection unit 100 and the output value of the OR gate 133.
- the output value of the AND gate 134 becomes the output value of the output control unit 130.
- FIG. 7 shows an example of an operation in overcurrent relay 30 according to the first embodiment. Note that the example shown in FIG. 7 illustrates an example in which the input current sharply increases due to the occurrence of a failure or the like at time t1, and the input current decreases at time t4 due to the breaker 4 being opened.
- FIG. 7 shows the current waveform of the input current, the output value of the overcurrent detection unit 100, the output value of the zero-crossing determination unit 120, the output value of the drop detection unit 110, and the output value of the output control unit 130. Have been.
- the zero-crossing determination unit 120 detects a zero-crossing point of the input current and outputs an output value “1”.
- the overcurrent detection unit 100 outputs the output value “1”.
- the output value of the zero-crossing determination unit 120 is “1”, but the output value of the drop detection unit 110 is “0”, so that the output control unit 130 outputs the output value “1”.
- the output control unit 130 outputs the operation output when the decrease in the effective value is not detected by the decrease detection unit 110 and the overcurrent is detected by the overcurrent detection unit 100.
- the overcurrent relay 30 outputs an operation output.
- the operation time corresponds to the time from time t1 to time t3.
- the input current sharply decreases.
- drop detection section 110 detects the sudden decrease in the input current and outputs an output value “1”. Further, when the input current sharply decreases, a zero-cross point unique to the AC waveform is not detected. Therefore, at time t6, zero-crossing determining section 120 determines that the zero-crossing point is no longer detected, and outputs output value “0”.
- the output control unit 130 outputs the output value “0” in response to the establishment of the output value “1” of the drop detection unit 110 and the output value “0” of the zero-cross determination unit 120. That is, the overcurrent relay 30 outputs a return signal.
- the return time corresponds to the time from time t4 to time t6.
- the output value of the overcurrent detector 100 is “1”, and at time t7, the output value becomes “0”. Therefore, as shown in FIG. 7, the output value of the drop detection unit 110 is “1” and the output value is “1”, It can be seen that the return time is shorter when the return output is performed based on the establishment of the output value “0” of the zero-crossing determination unit 120. Hereinafter, this reason will be specifically described.
- the overcurrent detection unit 100 uses current data from which a rated frequency component from which harmonic components, distortion components, and the like have been removed by the digital filter 101 is extracted in order to accurately perform overcurrent determination. Therefore, a phase shift occurs with respect to the rated frequency component.
- the effective value calculation by the effective value calculation unit 102 as shown in Expression (1), the effective value is calculated based on the current instantaneous value and the current instantaneous value in the past. Later, the effective value does not drop instantaneously but drops transiently. Therefore, the timing at which the effective value Ir is determined to be less than the set value Is is delayed, and it takes time for the output value of the overcurrent detection unit 100 to change from "1" to "0" even when the circuit breaker 4 is opened.
- the drop detection unit 110 also uses the effective value based on the current instantaneous value and the current instantaneous value in the past. Therefore, the drop detector 110 detects a drop in the effective value at an early stage (for example, at time t5) after the circuit breaker 4 is opened, and outputs an output value “1”.
- the zero-crossing determination unit 120 performs the zero-crossing determination based on the current data of the input current from which the harmonic component, the distortion component, and the like have not been removed by the digital filter 101, as described above. Therefore, there is no processing delay due to the digital filter 101. Further, since the zero-crossing determination is performed based on the current instantaneous value instead of the effective value using the past current instantaneous value, there is no delay in the determination timing.
- the zero-crossing determination unit 120 does not erroneously detect a zero-crossing point unique to the AC waveform.
- the first embodiment is configured to perform the return output by combining the detection result of the drop detection unit 110 and the determination result of the zero-cross determination unit 120.
- the output control unit 130 determines that the overcurrent has occurred when the decrease in the effective value Ir has been detected by the decrease detection unit 110 and the zero-cross point has not been detected by the zero-cross determination unit 120.
- a return output is generated regardless of the detection result of the detection unit 100. In other words, when it is determined that the zero-cross point is not detected during the period in which the effective value Ir is reduced and the zero-cross determination accuracy is high, a return output is generated. Note that a return output is not generated even if the zero-cross point has not been detected in the period Ta during which the decrease in the effective value Ir has not been detected.
- the energy stored in the inductance of the excitation circuit of the current transformer 7 is converted into the current.
- the decay current of the DC component flows for a certain time by discharging to the secondary side of the vessel 7.
- the recovery time can be shortened in the overcurrent relay 30 according to the first embodiment.
- FIG. 8 is a diagram illustrating an example of a DC (Direct Current) attenuation wave.
- a DC attenuation wave is generated even after the circuit breaker 4 is opened.
- the DC attenuation wave does not affect the determination accuracy of the zero-crossing determination unit 120 when the reduction in the effective value Ir is detected by the reduction detection unit 110.
- the zero-crossing determination unit 120 can appropriately determine whether a zero-crossing point has not been detected when the effective value Ir decreases. Therefore, even in the case where a DC attenuation wave is generated, the return time can be shortened by performing the return output by combining the detection result of the drop detection unit 110 and the determination result of the zero-cross determination unit 120.
- ⁇ Advantages> by combining the detection result of the decrease in the effective value Ir and the result of the zero-cross determination, a case where a harmonic component, a distortion component, or the like is superimposed on the fault current, and a DC attenuation wave are generated. Even in such a case, appropriate return of the overcurrent relay 30 can be realized, and the return time can be shortened.
- Embodiment 2 FIG.
- the configuration has been described in which, when a decrease in the effective value Ir is detected, a return output is generated when a condition that a zero-cross point of the current waveform of the input current is not detected is satisfied.
- the configuration is such that when a decrease in the effective value Ir is detected, a return output is generated when the condition that the DC component of the current waveform of the input current is more dominant than the AC component is satisfied.
- the configuration of the power system and the hardware configuration of the protection relay 20 and the overcurrent relay 30 in the second embodiment are the same as those in the first embodiment.
- FIG. 9 is a block diagram showing an example of a functional configuration of overcurrent relay 30A according to the second embodiment.
- the overcurrent relay 30A corresponds to the overcurrent relay 30 shown in FIG. 1, but is added with an additional symbol such as "A" for convenience to distinguish it from the other embodiments. This is the same in the following third embodiment.
- overcurrent relay 30A includes, as main functional components, overcurrent detection section 100, drop detection section 110, DC determination section 150, and output control section 170.
- each of these functions is realized by CPU 72 executing a program stored in ROM 73.
- a part or all of these functions may be configured to be realized by using a dedicated circuit. Since the configurations of overcurrent detecting section 100 and drop detecting section 110 are the same as those in the first embodiment, detailed description thereof will not be repeated.
- the DC determination unit 150 determines whether or not the DC component of the current waveform of the input current converted into digital data by the AD conversion unit 52 is more dominant than the AC component of the current waveform.
- FIG. 10 is a block diagram showing an example of a functional configuration of DC determining section 150 according to the second embodiment.
- DC determination section 150 includes a fundamental wave detection filter 151, an AC effective value calculation section 152, a DC detection filter 153, and a comparison section 154.
- the fundamental wave detection filter 151 generates current data obtained by extracting the rated frequency component (that is, the fundamental wave component) of the input current.
- the fundamental wave detection filter 151 uses, for example, data corresponding to ⁇ ⁇ ⁇ ⁇ cycle (that is, 180 °) of the electrical angle at the rated frequency.
- the fundamental wave detection filter 151 has the same function as the digital filter 101.
- the AC effective value calculator 152 performs an AC effective value calculation of the input current from which the rated frequency component has been extracted. Specifically, the AC effective value calculation unit 152 calculates the effective value of the AC component (hereinafter, also referred to as “AC effective value”) using the current data input from the fundamental wave detection filter 151. The AC effective value calculation unit 152 calculates the AC effective value using, for example, the following equation (4).
- Ira (t) sqrt (
- Ira (t) indicates the effective value at time t.
- Ia (t) indicates the current instantaneous value of the AC component of the input current at the time t
- Ia (t-90) indicates the current instantaneous value 90 electrical degrees before the time t
- Ia (T-180) indicates the instantaneous current value 180 electrical degrees before the time t.
- AC effective value calculation section 152 has the same function as effective value calculation section 102.
- the DC detection filter 153 generates current data obtained by extracting the DC component of the input current.
- the DC detection filter 153 uses, for example, data for a half cycle (that is, 180 °) of the electrical angle at the rated frequency.
- the DC component of the extracted input current at time t is defined as Idc (t).
- the comparing unit 154 compares the AC effective value Ira (t) with the DC component Idc (t), and the DC component Idc (t) is significantly larger and dominant than the AC effective value Ira (t). In this case, the output value "1" is output.
- the DC component Idc (t) is larger than the AC effective value Ira (t)
- the comparison unit 154 outputs an output value “0” when Idc (t) ⁇ Th2 * Ira is satisfied.
- the output of the comparison unit 154 is the output of the DC determination unit 150. That is, the DC determination unit 150 outputs the output value “1” when determining that the DC component is more dominant than the AC component, and outputs the output value “0” when determining that it is not. I do. This output value corresponds to the determination result of DC determining section 150.
- output control section 170 outputs an operation output and a return based on the detection result of overcurrent detection section 100, the detection result of drop detection section 110, and the determination result of DC determination section 150. Generate output.
- output control section 170 includes AND gates 171 and 172.
- the AND gate 171 performs an AND operation on the output value of the drop detection unit 110 and the output value of the DC determination unit 150.
- the AND gate 172 performs an AND operation on the output value of the overcurrent detection unit 100 and a value obtained by inverting the output value of the AND gate 171.
- the output value of the AND gate 172 becomes the output value of the output control unit 170.
- FIG. 11 shows an example of an operation in overcurrent relay 30A according to the second embodiment. Note that the example illustrated in FIG. 11 illustrates an example in which the input current rapidly increases due to the occurrence of a failure or the like at time t1a, and the input current decreases due to the opening of the circuit breaker 4 at time t3a.
- FIG. 11 shows the current waveform of the input current, the output value of the overcurrent detection unit 100, the output value of the DC determination unit 150, the output value of the drop detection unit 110, and the output value of the output control unit 170. Have been.
- the output value of the drop detection unit 110 is “0”, so that the output control unit 170 outputs the output value “1” as the overcurrent detection unit 100 outputs the output value “1”. . That is, the overcurrent relay 30A outputs an operation output.
- the operation time corresponds to the time from time t1a to time t2a.
- the output control unit 170 outputs the output value “0” in response to the establishment of the output value “1” of the drop detection unit 110 and the output value “1” of the DC determination unit 150. That is, the overcurrent relay 30A outputs a return signal.
- the return time corresponds to the time from time t4a to time t5a.
- the output value of the overcurrent detection unit 100 is “1”, and at time t6a, the output value becomes “0”. Therefore, as shown in FIG. 11, the output value of the drop detection unit 110 is “1” and the output value of the drop detection unit 110 is smaller than the case where the return output is performed based on the output value of the overcurrent detection unit 100 becoming “0”. It can be seen that the return time is shortened when the return output is performed based on the establishment of the output value “1” of the DC determination unit 150.
- the DC determination unit 150 also performs the filtering process and the effective value calculation process in the same manner as the overcurrent detection unit 100. However, unlike the overcurrent determination, the DC determination unit 150 only needs to be able to determine that the DC component has become dominant. Therefore, the DC determination unit 150 determines that the DC component has become dominant early (for example, at time t4a) after the circuit breaker 4 is opened, and outputs an output value “1”. Further, as described above, the drop detection unit 110 also detects a drop in the effective value at an early stage (for example, time t5a) after the circuit breaker 4 is opened, and outputs an output value “1”.
- the DC The unit 150 can execute the above determination with high accuracy.
- the second embodiment is configured to perform a return output by combining the detection result of the drop detection unit 110 and the determination result of the DC determination unit 150. More specifically, the output control unit 170 is configured to perform the operation when the decrease in the effective value Ir is detected by the decrease detection unit 110 and when the DC determination unit 150 determines that the DC component is more dominant than the AC component. Then, a return output is generated regardless of the detection result of the overcurrent detection unit 100.
- the DC attenuation wave shown in FIG. 8 is an attenuation wave containing almost no AC component. Therefore, even when a DC attenuation wave is generated after the circuit breaker 4 is opened, the DC determination unit 150 can accurately detect the DC attenuation wave. Therefore, also in this case, the return time can be shortened by performing the return output by combining the detection result of the drop detection unit 110 and the determination result of the DC determination unit 150.
- the second embodiment has the same advantages as the first embodiment.
- Embodiment 3 FIG. In Embodiments 1 and 2 described above, the configuration using one overcurrent detection unit 100 has been described. In Embodiment 3, a configuration using two overcurrent detection units will be described. Note that the configuration of the power system and the hardware configuration of the protection relay 20 and the overcurrent relay 30 in the third embodiment are the same as those in the first embodiment.
- FIG. 12 is a block diagram showing an example of a functional configuration of overcurrent relay 30B according to the third embodiment.
- overcurrent relay 30 ⁇ / b> B includes, as main functional components, overcurrent detection section 100, drop detection section 110, overcurrent detection section 200, and output control section 210.
- each of these functions is realized by CPU 72 executing a program stored in ROM 73.
- a part or all of these functions may be configured to be realized by using a dedicated circuit. Since the configurations of overcurrent detecting section 100 and drop detecting section 110 are the same as those in the first embodiment, detailed description thereof will not be repeated.
- the overcurrent detection unit 200 includes a digital filter 201, an effective value calculation unit 202, an overcurrent determination unit 203, and an overcurrent determination unit 204.
- the digital filter 201 generates current data obtained by extracting the rated frequency component of the input current.
- the digital filter 201 has high-speed filter characteristics with a shorter sampling data length than the digital filter 101.
- data of a period T2 for 1/4 cycle (that is, 90 °) of the electrical angle of the rated frequency is used. This corresponds to data for three sampling lengths, for example, when the number of times of sampling of the AD conversion unit 52 is 12 in one cycle. That is, the period T2 is shorter than the period T1 of the data used by the digital filter 101.
- the effective value calculation unit 202 performs an effective value calculation of the input current from which the rated frequency component has been extracted. Specifically, the effective value calculation unit 202 calculates the effective value using the current data input from the digital filter 201.
- the effective value calculation unit 202 uses an effective value calculation expression having a transient characteristic that more quickly follows a change in the input current than the expression (1) used in the effective value calculation unit 102. For example, the effective value calculation unit 202 calculates the effective value using, for example, the following equation (5).
- Irb (t) sqrt (
- Irb (t) indicates the effective value at time t.
- Ib (t) indicates a current instantaneous value of the input current at the time t from which the rated frequency component is extracted
- Ib (t ⁇ 30) indicates a current instantaneous value 30 electrical degrees before the time t.
- Ib (t ⁇ 60) indicate the current instantaneous value 60 electrical degrees before the time t
- Ib (t ⁇ 90) indicates the current instantaneous value 90 electrical degrees before the time t.
- the time required to obtain data used for calculating the effective value is a time equivalent to 1/4 cycle of the electrical angle. Therefore, the dynamic response is high, and the speed can be increased by a time corresponding to 1/4 cycle of the electrical angle as compared with the equation (1) used in the effective value calculation unit 102.
- the overcurrent determining unit 203 compares the effective value Irb calculated by the effective value calculating unit 202 with the set value Is1 to determine whether there is an overcurrent.
- the overcurrent determining unit 203 outputs an output value “1” when the effective value Irb is equal to or more than the set value Is1, and outputs an output value “0” when the effective value Irb is less than the set value Is1.
- the output value of the overcurrent determination unit 203 corresponds to the overcurrent detection result Dy output by the overcurrent detection unit 200.
- the overcurrent determining unit 204 compares the effective value Irb calculated by the effective value calculating unit 202 with the set value Is2 to determine the presence or absence of an overcurrent.
- the overcurrent determination unit 204 outputs an output value “1” when the effective value Irb is equal to or more than the set value Is2, and outputs an output value “0” when the effective value Irb is less than the set value Is2.
- the output value of the overcurrent determination unit 204 corresponds to the overcurrent detection result Dz output by the overcurrent detection unit 200.
- the overcurrent detection unit 200 compares the effective value Irb calculated using the current data of the period T2 shorter than the period T1 with the set value Is1 larger than the set value Is, thereby detecting the overcurrent.
- the detection result Dy is output.
- the overcurrent detection unit 200 outputs an overcurrent detection result Dz by comparing the effective value Irb with a set value Is2 smaller than the set value Is.
- the overcurrent detection unit 200 uses data of a relatively short period, it is possible to execute a higher-speed operation than the overcurrent detection unit 100.
- the error of the effective value calculation result of the overcurrent detection unit 200 is larger than that of the effective value calculation result of the overcurrent detection unit 100. Therefore, the output control unit 210 is configured to suppress the error of the effective value calculation result from affecting the operation and return accuracy of the overcurrent relay 30B.
- the output control unit 210 outputs an operation output based on the detection result Dx output from the overcurrent detection unit 100, the detection results Dy and Dz output from the overcurrent detection unit 200, and the detection result of the drop detection unit 110. And generate a return output.
- the output control unit 210 includes OR gates 211 and 215 and AND gates 212, 213 and 214.
- OR gate 211 performs an OR operation on the output value of overcurrent determination section 103 (ie, detection result Dx) and the output value of overcurrent determination section 203 (ie, detection result Dy).
- AND gate 212 performs an AND operation on the output value of overcurrent determination section 103 (ie, detection result Dx) and the output value of overcurrent determination section 204 (ie, detection result Dz).
- the AND gate 213 performs an AND operation on the output value of the OR gate 211 and a value obtained by inverting the output value of the drop detection unit 110.
- the AND gate 214 performs an AND operation on the output value of the AND gate 212 and the output value of the drop detection unit 110.
- OR gate 215 performs an OR operation on the output value of AND gate 213 and the output value of AND gate 214.
- the output value of the OR gate 215 becomes the output value of the output control unit 210.
- the output value of the overcurrent determination unit 103 (that is, the detection result Dx) and the output value of the overcurrent determination unit 203 (that is, the output value)
- the OR operation with the detection result Dy becomes the output value of the output control unit 210.
- the output control unit 210 outputs the operation output at the earlier output timing of the detection result Dx indicating that the overcurrent has been detected and the detection result Dy indicating that the overcurrent has been detected. Generate.
- the output value of the overcurrent determination unit 103 (that is, the detection result Dx) and the output value of the overcurrent determination unit 204 (that is, the detection result An AND operation with Dz) is an output value of the output control unit 210.
- the output control unit 210 returns at the earlier output timing of the detection result Dx indicating that the overcurrent has not been detected and the detection result Dz indicating that the overcurrent has not been detected. Generate output.
- both the operation time and the recovery time can be shortened while suppressing the error of the effective value calculation result by the overcurrent detection unit 200 from affecting the operation and recovery accuracy of the overcurrent relay 30B.
- the output value of the overcurrent determination unit 103 and the output value of the overcurrent determination unit 204 A return output is generated. Therefore, even when the fault current includes many harmonic components and distortion components, it is necessary to change the set value Is2 used in the overcurrent determination unit 204 to a value significantly lower than the set value Is. Therefore, the return time can be shortened.
- FIG. 13 shows an example of an operation in overcurrent relay 30B according to the third embodiment. Note that the example shown in FIG. 13 shows an example in which the input current suddenly increases due to the occurrence of a failure or the like at time t1b, and the input current decreases due to the opening of the circuit breaker 4 at time t5b.
- FIG. 13 illustrates the current waveform of the input current, the output value of the overcurrent detection unit 100 (that is, the detection result Dx), the output value of the overcurrent determination unit 203 (that is, the detection result Dy), and the overcurrent determination unit.
- the output value of 204 that is, the detection result Dz
- the output value of the drop detection unit 110 the output value of the output control unit 210 are shown.
- the overcurrent determination unit 204 outputs an output value “1” in accordance with the establishment of the effective value Irb ⁇ Is2. At this point, no operation output is generated by the output control unit 210. Subsequently, at time t3b, the overcurrent determination unit 203 outputs an output value “1” in accordance with the establishment of the effective value Irb ⁇ Is1. At this time, the output control unit 210 outputs an output value “1”. That is, the overcurrent relay 30B outputs an operation. The operation time corresponds to the time from time t1b to time t3b.
- the output value of the overcurrent detection unit 100 is “0”, and at time t4b, the output value becomes “1”. Therefore, as shown in FIG. 13, the output values “0” and “0” of the drop detection unit 110 are smaller than the case where the operation output is performed based on the output value of the overcurrent detection unit 100 being “1”. When the operation output is performed based on the establishment of the output value “1” of the overcurrent determination unit 203, the operation time is reduced.
- the circuit breaker 4 opens at the time t5b, the input current sharply decreases.
- drop detection section 110 detects the sudden decrease in the input current and outputs an output value “1”.
- the overcurrent determination unit 203 outputs an output value “0” in response to the establishment of the effective value Irb ⁇ Is1.
- the output control unit 210 does not generate a return output.
- the overcurrent determination unit 204 outputs an output value “0” according to the establishment of the effective value Irb ⁇ Is2.
- the output control unit 210 outputs an output value “0”. That is, the overcurrent relay 30B outputs a return signal.
- the return time corresponds to the time from time t5b to time t8b.
- the output value of the overcurrent detection unit 100 is “1”, and at time t9b, the output value becomes “0”. Therefore, as shown in FIG. 13, the output value “1” of the drop detection unit 110 and the output value “1” of the drop detection unit 110 are smaller than the case where the return output is performed based on the output value of the overcurrent detection unit 100 becoming “0”. It can be seen that the return time is shorter when the return output is performed based on the establishment of the output value “0” of the overcurrent determination unit 204.
- the overcurrent relay 30B operates and outputs at the timing when the output value “1” is output by the overcurrent determination unit 203 when the input current suddenly increases due to a failure or the like, and when the input current sharply decreases. Returns at the timing when the output value “0” is output by the overcurrent determination unit 204. Therefore, it is possible to operate and return at high speed based on the effective value calculation result obtained by the overcurrent detection unit 200 using the high-speed effective value calculation formula (5).
- the operation time and the recovery time are suppressed while suppressing the error of the effective value calculation result by the overcurrent detection unit 200 using a relatively short data length from affecting the operation and the recovery accuracy of the overcurrent relay 30B. Can be accelerated together. Further, even when the fault current includes many harmonic components and distortion components, the recovery time can be shortened.
- the overcurrent relay may be configured to be used as a protection relay that detects a fault current flowing in a power system (for example, a transmission line) and outputs a trip signal to a circuit breaker.
- the configuration illustrated as the above-described embodiment is an example of the configuration of the present invention, and can be combined with another known technology, and a part is omitted without departing from the gist of the present invention. It is also possible to change and configure.
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Abstract
Description
<電力系統の構成>
図1は、保護継電システムが設置された電力系統の全体構成の一例を模式的に示す図である。図1に示す電力系統では、電線1が母線2,3に接続されている。さらに、電線1には、遮断器4,5,6および電流変成器7が設けられている。図1の電力系統が三相交流用の場合には、遮断器4,5,6および電流変成器7は各相の電線に設けられる。
図2は、過電流継電器30のハードウェア構成の一例を示す図である。図2を参照して、過電流継電器30は、補助変成器51と、AD(Analog to Digital)変換部52と、演算処理部70とを含む。過電流継電器30は、ディジタル保護継電装置として構成されている。なお、保護継電器20のハードウェア構成は、図2に示すハードウェア構成と同様である。
図3は、実施の形態1に従う過電流継電器30の機能構成の一例を示すブロック図である。図3を参照して、過電流継電器30は、主たる機能構成として、過電流検出部100と、低下検出部110と、ゼロクロス判定部120と、出力制御部130とを含む。典型的には、これらの各機能は、CPU72がROM73に格納されたプログラムを実行することによって実現される。なお、これらの機能の一部または全部は専用の回路を用いることによって実現されるように構成されていてもよい。
ここで、Ir(t)は、時刻tにおける実効値を示している。また、I(t)は、時刻tにおける、定格周波数成分が抽出された入力電流の電流瞬時値を示し、I(t-90)は、時刻tより電気角90°前の電流瞬時値を示しており、I(t-180)は、時刻tより電気角180°前の電流瞬時値を示している。なお、式(1)では、実効値演算に用いるデータを得るために必要な時間は電気角の1/2サイクル分の時間である。
|Ir(t)-Ir(t-180)|≧Th1*Ir(t-180)・・・(3)
ここで、Ir(t)は、時刻tにおける実効値を示している。また、Ir(t-180)は、時刻tより電気角180°前の実効値を示している。
図7は、実施の形態1に従う過電流継電器30における動作の一例を示す図である。なお、図7に示す例では、時刻t1において故障等が発生することで入力電流が急増し、時刻t4において、遮断器4が開放することで入力電流が減少した例を示している。図7には、入力電流の電流波形と、過電流検出部100の出力値と、ゼロクロス判定部120の出力値と、低下検出部110の出力値と、出力制御部130の出力値とが示されている。
実施の形態1によると、実効値Irの低下検出結果と、ゼロクロス判定結果とを組み合わせることにより、故障電流に高調波成分、歪み成分等が重畳している場合およびDC減衰波が発生している場合であっても、過電流継電器30の適切な復帰を実現できるとともに、その復帰時間を高速化することができる。
実施の形態1では、実効値Irの低下が検出された場合に、入力電流の電流波形のゼロクロス点が検出されないとの条件が成立した場合に、復帰出力を生成する構成について説明した。実施の形態2では、実効値Irの低下が検出された場合に、入力電流の電流波形の直流成分が交流成分よりも支配的であるとの条件が成立した場合に、復帰出力を生成する構成について説明する。なお、実施の形態2における電力系統の構成と、保護継電器20ならびに過電流継電器30のハードウェア構成とは、実施の形態1の当該構成と同様である。
図9は、実施の形態2に従う過電流継電器30Aの機能構成の一例を示すブロック図である。過電流継電器30Aは図1に示す過電流継電器30に対応するが、他の実施の形態との区別のため、便宜上「A」といった追加の符号を付している。これは、以下の実施の形態3でも同様である。
ここで、Ira(t)は、時刻tにおける実効値を示している。また、Ia(t)は、時刻tにおける、入力電流の交流成分の電流瞬時値を示し、Ia(t-90)は、時刻tより電気角90°前の電流瞬時値を示しており、Ia(t-180)は、時刻tより電気角180°前の電流瞬時値を示している。典型的には、交流実効値演算部152は、実効値演算部102と同様の機能を有する。
図11は、実施の形態2に従う過電流継電器30Aにおける動作の一例を示す図である。なお、図11に示す例では、時刻t1aにおいて故障等が発生することで入力電流が急増し、時刻t3aにおいて、遮断器4が開放することで入力電流が減少した例を示している。図11には、入力電流の電流波形と、過電流検出部100の出力値と、直流判定部150の出力値と、低下検出部110の出力値と、出力制御部170の出力値とが示されている。
実施の形態2によると、実施の形態1と同様の利点を有する。
上述した実施の形態1,2では、1つの過電流検出部100を用いる構成について説明したが、実施の形態3では2つの過電流検出部を用いる構成について説明する。なお、実施の形態3における電力系統の構成と、保護継電器20および過電流継電器30のハードウェア構成とは、実施の形態1の当該構成と同様である。
図12は、実施の形態3に従う過電流継電器30Bの機能構成の一例を示すブロック図である。図12を参照して、過電流継電器30Bは、主たる機能構成として、過電流検出部100と、低下検出部110と、過電流検出部200と、出力制御部210とを含む。典型的には、これらの各機能は、CPU72がROM73に格納されたプログラムを実行することによって実現される。なお、これらの機能の一部または全部は専用の回路を用いることによって実現されるように構成されていてもよい。過電流検出部100および低下検出部110の構成は、実施の形態1と同様であるため、その詳細な説明は繰り返さない。
ここで、Irb(t)は、時刻tにおける実効値を示している。また、Ib(t)は、時刻tにおける、定格周波数成分が抽出された入力電流の電流瞬時値を示し、Ib(t-30)は、時刻tより電気角30°前の電流瞬時値を示し、Ib(t-60)は、時刻tより電気角60°前の電流瞬時値を示し、Ib(t-90)は、時刻tより電気角90°前の電流瞬時値を示している。
図13は、実施の形態3に従う過電流継電器30Bにおける動作の一例を示す図である。なお、図13に示す例では、時刻t1bにおいて故障等が発生することで入力電流が急増し、時刻t5bにおいて、遮断器4が開放することで入力電流が減少した例を示している。図13には、入力電流の電流波形と、過電流検出部100の出力値(すなわち、検出結果Dx)と、過電流判定部203の出力値(すなわち、検出結果Dy)と、過電流判定部204の出力値(すなわち、検出結果Dz)と、低下検出部110の出力値と、出力制御部210の出力値とが示されている。
実施の形態3によると、比較的短いデータ長を用いる過電流検出部200による実効値演算結果の誤差が過電流継電器30Bの動作および復帰の精度に影響することを抑えつつ、動作時間および復帰時間をともに高速化することができる。また、故障電流に高調波成分、および歪波成分が多く含まれている場合であっても、復帰時間の高速化を実現することができる。
上述した実施の形態では、過電流継電器がCBFリレーとして機能する構成について説明したが、当該構成に限られない。過電流継電器は、電力系統(例えば、送電線)に流れる事故電流を検出して遮断器へトリップ信号を出力するような保護継電器として用いる構成であってもよい。
Claims (9)
- 電力系統から入力された入力電流の実効値と、整定値とを比較することにより過電流を検出する過電流検出部と、
前記実効値の低下を検出する低下検出部と、
前記過電流検出部の検出結果と、前記低下検出部の検出結果と、前記入力電流の電流波形に関する予め定められた条件とに基づいて、動作出力および復帰出力を生成する出力制御部とを備え、
前記出力制御部は、前記実効値の低下が検出された場合であって、かつ前記予め定められた条件が成立した場合には、前記過電流検出部による検出結果に関わらず前記復帰出力を生成する、過電流継電器。 - 前記出力制御部は、前記実効値の低下が検出されていない場合であって、かつ前記過電流検出部により過電流が検出された場合に、前記動作出力を生成する、請求項1に記載の過電流継電器。
- 前記低下検出部は、前記実効値の低下率が第1閾値以上である場合に、前記実効値の低下を検出する、請求項1または請求項2に記載の過電流継電器。
- 前記入力電流の電流波形のゼロクロス点が検出されたか否かを判定するゼロクロス判定部をさらに備え、
前記出力制御部は、前記実効値の低下が検出された場合であって、かつ前記ゼロクロス点が検出されない場合に、前記復帰出力を生成する、請求項1~請求項3のいずれか1項に記載の過電流継電器。 - 前記入力電流の電流波形の直流成分が前記電流波形の交流成分よりも支配的であるか否かを判定する判定部をさらに備え、
前記出力制御部は、前記実効値の低下が検出された場合であって、かつ前記直流成分が前記交流成分よりも支配的である場合に、前記復帰出力を生成する、請求項1~請求項3のいずれか1項に記載の過電流継電器。 - 前記判定部は、前記電流波形の直流成分が前記電流波形の交流成分の実効値よりも大きく、かつ前記交流成分の実効値に対する前記直流成分の比率が第2閾値以上である場合に、前記直流成分が前記交流成分よりも支配的であると判定する、請求項5に記載の過電流継電器。
- 前記過電流検出部は、
前記入力電流の定格周波数成分を抽出した電流データを生成するディジタルフィルタと、
前記電流データを用いて前記実効値を演算する実効値演算部とを含む、請求項1~請求項6のいずれか1項に記載の過電流継電器。 - 電力系統から入力された入力電流の定格周波数成分を抽出した第1電流データを生成する第1デジタルフィルタを含む第1過電流検出部と、
前記第1デジタルフィルタよりも高速なフィルタ特性を有し、前記入力電流の定格周波数成分を抽出した第2電流データを生成する第2デジタルフィルタを含む第2過電流検出部とを備え、
前記第1過電流検出部は、第1期間の前記第1電流データを用いて演算された第1実効値と、第1整定値とを比較することにより過電流の第1検出結果を出力し、
前記第2過電流検出部は、前記第1期間よりも短い第2期間の前記第2電流データを用いて演算された第2実効値と、前記第1整定値よりも大きい第2整定値とを比較することにより過電流の第2検出結果を出力し、前記第2実効値と前記第1整定値よりも小さい第3整定値との比較することにより過電流の第3検出結果を出力し、
前記第1実効値が低下したことを検出する低下検出部と、
前記第1~第3検出結果と、前記低下検出部の検出結果とに基づいて、動作出力および復帰出力を生成する出力制御部とをさらに備え、
前記出力制御部は、前記第1実効値の低下が検出された場合には、過電流が未検出であることを示す前記第1検出結果、および過電流が未検出であることを示す前記第3検出結果のうち、いずれか早い方の出力タイミングで前記復帰出力を生成する、過電流継電器。 - 前記出力制御部は、前記第1実効値の低下が検出されていない場合には、過電流が検出されたことを示す前記第1検出結果、および過電流が検出されたことを示す前記第2検出結果のうち、いずれか早い方の出力タイミングで前記動作出力を生成する、請求項8に記載の過電流継電器。
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JP2001177977A (ja) * | 1999-12-20 | 2001-06-29 | Meidensha Corp | ディジタル形保護継電装置 |
JP2004064957A (ja) * | 2000-07-18 | 2004-02-26 | Sungkyunkwan Univ | 送電線路における可変デッドタイム制御を利用した適応的再閉路方法 |
JP2011250518A (ja) * | 2010-05-24 | 2011-12-08 | Mitsubishi Electric Corp | 過電流継電器 |
JP2012161132A (ja) * | 2011-01-31 | 2012-08-23 | Mitsubishi Electric Corp | 過電流継電器 |
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JPS59169543U (ja) * | 1983-04-28 | 1984-11-13 | 日新電機株式会社 | 過電流継電器 |
JP2001177977A (ja) * | 1999-12-20 | 2001-06-29 | Meidensha Corp | ディジタル形保護継電装置 |
JP2004064957A (ja) * | 2000-07-18 | 2004-02-26 | Sungkyunkwan Univ | 送電線路における可変デッドタイム制御を利用した適応的再閉路方法 |
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JP2012161132A (ja) * | 2011-01-31 | 2012-08-23 | Mitsubishi Electric Corp | 過電流継電器 |
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