JP6565425B2 - Isolated operation detection device, isolated operation detection method, and isolated operation detection program - Google Patents

Description

  The present invention relates to an isolated operation detection device, an isolated operation detection method, and an isolated operation detection program.

  When a part of a system connected to a power generation facility composed of distributed power sources is disconnected from the system power source due to an accident or the like, power generation is continued only with the power generation facility on the disconnected line, and the load on the line is The state in which electric power is supplied to is called single operation. Independent operation may affect the safety of personnel and equipment, and may increase damage at the accident point and delay recovery. Therefore, it is desirable that the isolated operation is detected early and reliably.

  As an example of a distributed power source that is connected to the grid, a solar power generation system, a fuel cell power generation system, and the like can be given. Such a distributed power source includes a DC power source such as a solar cell or a fuel cell, and an interconnection inverter that converts DC power output from the DC power source into AC power supplied to a load or a system power source side. The interconnection inverter is, for example, a power conditioner (PCS). The function for detecting the isolated operation described above is provided, for example, in the interconnection inverter.

  As a method for detecting the isolated operation, there is a method in which the interconnection inverter receives a transfer interruption signal transmitted from the system side circuit breaker. In addition, as a method for detecting an isolated operation, there is a method in which a connected inverter monitors a change in voltage, frequency, etc. of a locally operated independent system including a distributed power source and a load formed by opening a system side circuit breaker. . Among these, methods for monitoring changes in the voltage and frequency of the local system are roughly classified into a passive method and an active method.

  The passive method is a method that uses the change in voltage and frequency of the local system when the power flow at the grid connection point (system side circuit breaker) changes to 0 in the local system disconnected from the system power supply. . Therefore, when the power generation amount of the distributed power source and the load amount in the local system are balanced and the power flow at the grid connection point is 0, the power flow will not change due to the disconnection from the system power supply. The system does not detect isolated operation. In other words, the passive system has a dead zone when the tide is near zero. Therefore, various active methods have been proposed that do not have such a dead zone region in which isolated operation is not detected.

  In the active method, an active signal added to the power generation output of the interconnected inverter (for example, reactive power or active power fluctuation) is injected into the system, and system information (for example, system frequency or system voltage) that appears during single operation Isolated operation is detected from the change in An example of the active method includes a frequency feedback method in addition to a conventional active method such as a frequency shift method, a slip mode frequency shift method, a reactive power fluctuation method, and a load fluctuation method.

  The frequency shift method is a method of detecting a frequency change of a local system that appears at the time of shifting to an isolated operation by giving a frequency bias in advance to an internal transmitter of the interconnection inverter. In the slip mode frequency shift method, the grid inverter has the output current phase sudden change characteristic with respect to the frequency change, and positive feedback of the minute frequency change that occurs in the local system at the time of shifting to independent operation, the frequency of the local system is diverge. This is a method of detecting an isolated operation by changing as shown. The reactive power fluctuation method is a method of applying a periodic reactive power fluctuation to the power generation output of the grid inverter and detecting a frequency change of the local system that appears at the time of shifting to an independent operation. The load fluctuation method is a method of detecting a sudden change in voltage fluctuation or current fluctuation by inserting parallel impedance into a grid-connected inverter instantaneously and periodically. The frequency feedback method is a method for detecting isolated operation at a higher speed than the conventional active method by injecting reactive power that increases the frequency change of the local system into the system from the interconnection inverter at the time of transition to isolated operation. .

  Patent Document 1 is known as a related technique. In Patent Document 1, a change pattern of the latest system cycle is created based on a deviation between the latest system cycle and a past system cycle by a predetermined system cycle. Then, by comparing each of the plurality of created change patterns with a plurality of threshold values set in a stepwise manner, it is determined whether or not there is an isolated operation.

JP 2007-215392 A

  However, in the active method as described above, a change in system information due to the output of a distributed power source, a load fluctuation, a system fault or the like is erroneously detected as a change due to an isolated operation, and the distributed power source is disconnected from the system. May cause unnecessary operation.

  An object according to one aspect of the present invention is to provide an isolated operation detection device in which erroneous detection of an isolated operation is reduced.

An isolated operation detection device according to an embodiment includes a command detection unit, an activation signal generation unit, and an isolated operation determination unit. The command detection unit detects an active signal command exceeding a predetermined threshold for an active signal injected from the grid inverter to the system. The active signal command is a reactive current command or a reactive power command. The enabling signal generating unit generates an enabling signal for enabling detecting the isolated operation of the interconnection inverter according to the system information detected from the system from the active signal command detected by the command detecting unit . The isolated operation determination unit determines the presence or absence of isolated operation from the isolated operation detection signal and the activation signal detected according to the system information, and outputs an isolated operation detection signal according to the determination result.

  According to the isolated operation detection device according to one embodiment, erroneous detection of isolated operation can be reduced.

It is a figure which shows the structural example of the interconnection inverter containing the independent operation detection apparatus according to embodiment. It is a figure which shows the 1st structural example of the isolated operation detection apparatus according to embodiment. It is a flowchart of the 1st example of the islanding operation detection method according to an embodiment. It is a figure which shows the 1st example of an active signal command, an enabling signal, system | strain information, and an independent operation detection signal. It is a figure which shows the 2nd structural example of the isolated operation detection apparatus according to embodiment. It is a flowchart of the 2nd example of the independent operation detection method according to embodiment. It is a figure which shows the 2nd example of an active signal command, an enabling signal, system | strain information, and an independent operation detection signal. It is a figure which shows the structural example of the computer which performs the independent operation detection program according to embodiment.

Hereinafter, embodiments for carrying out the invention will be described in detail with reference to the drawings.
FIG. 1 is a diagram illustrating a configuration example of a grid-connected inverter including an isolated operation detection device according to an embodiment. In the example shown in FIG. 1, the isolated operation detection device 1 is included in the interconnection inverter 2. FIG. 1 shows a DC power source 3, a load 4, a system power source 5, and a system side circuit breaker 6 in addition to the interconnection inverter 2.

  The interconnected inverter 2 and the DC power source 3 constitute a distributed power source. The DC power source 3 is, for example, a solar cell when the distributed power source is a solar system, and a fuel cell when the distributed power source is a fuel cell system. The DC power supply 3, the interconnection inverter 2, and the load 4 are connected to the system power supply 5 via the system side circuit breaker 6, and constitute a local system. The system power supply 5 is approximated by an infinite bus.

  In the example shown in FIG. 1, the interconnection inverter 2 is configured to support a frequency feedback system. As can be understood from the following description, the isolated operation detection device 1 is applicable not only to the frequency feedback method but also to an existing active method. Examples of the existing active method include a frequency shift method, a slip mode frequency shift method, a reactive power fluctuation method, and a load fluctuation method in addition to the frequency feedback method.

  The interconnection inverter 2 includes an inverter circuit 201, an AC reactor 202, a current detector 203, a capacitor 204, an inverter-side switch 205, and an instrument transformer 206 in addition to the isolated operation detection device 1. The interconnected inverter 2 further includes a period detector 207, a voltage detector 208, a reference signal generation circuit 209, a coordinate converter 210, an output current control circuit 211, and a gate signal generation circuit 212.

  The inverter circuit 201 is a circuit that converts DC power output from the DC power source 3 into AC power, and is, for example, a three-phase AC inverter circuit. The power generation output (three-phase AC power) of the inverter circuit 201 is input to the load 4 constituting the local system via the AC reactor 202, the current detector 203, the capacitor 204, and the inverter-side switch 205.

  The period detector 207 detects the system period from the voltage input via the instrument transformer 206 provided on the system side of the inverter side switch 205. Note that the period detector 207 may be configured to detect the system frequency from the voltage input via the instrument transformer 206. The system cycle (or system frequency) detected by the cycle detector 207 is output to the isolated operation detection device 1. The voltage detector 208 detects the system voltage from the voltage input via the instrument transformer 206. The system voltage detected by the voltage detector 208 is output to the isolated operation detection device 1.

  The isolated operation detection device 1 outputs an active signal command according to changes in the input system information. Specifically, when the isolated operation detection device 1 is configured to support the frequency feedback method, the isolated operation detection device 1 operates as follows. That is, when the isolated operation detection device 1 detects a deviation from the steady state of the inputted system cycle (or system frequency), it outputs a reactive current command corresponding to the deviation. For example, the isolated operation detection device 1 outputs a reactive current command with an advanced phase when a deviation in which the system frequency is increased is detected, and an invalid phase with a delay when a deviation in which the system frequency is decreased is detected. Outputs the current command.

  The reference signal generation circuit 209 generates a three-phase AC reference signal synchronized with the frequency of the system power supply 5 from the waveform of the system voltage detected via the instrument transformer 206. In accordance with the generated three-phase AC reference signal, the coordinate converter 210 synchronizes the input active current command (d-axis current command) and reactive current command (q-axis current command) with the frequency of the system power supply 5. Convert to AC current command. The output current control circuit 211 generates a correction value for the three-phase AC voltage command value so that the output current value of the inverter circuit 201 detected by the current detector 203 matches the three-phase AC current command value. The gate signal generation circuit 212 generates a modulation signal by adding a correction value to the three-phase AC voltage command value for each phase, and generates a gate signal by superimposing the modulation signal on the carrier signal. The generated gate signal is output to the inverter circuit 201.

  The inverter circuit 201 converts the input DC power into three-phase AC power by turning on or off switching elements (not shown) constituting the inverter circuit 201 according to the input gate signal. The inverter circuit 201 outputs three-phase AC power to the load 4, and the period detector 207 detects the system period. Thus, the system cycle (or system frequency) of the local system according to the output reactive current command is fed back to the isolated operation detection device 1.

  At the time of shifting to the independent operation, the voltage of the local system is determined according to the output current of the interconnection inverter. For this reason, the phase of the output current of the interconnection inverter also advances (or delays) in accordance with the reactive current command whose phase has advanced (or delayed), and the phase of the voltage of the local system also advances (or delays). The interconnected inverter generates a three-phase AC reference signal synchronized with the voltage waveform with the phase advanced (or delayed) detected from the local system by the reference signal generation circuit 209, and the phase is further increased based on this reference signal. Determine the output current according to the advanced (or delayed) reactive current command. These operations are performed continuously, and the phase advance (or delay) proceeds in a chain. Since the advance of the phase leads to an increase in frequency and the delay causes a decrease in frequency, the absolute value of the reactive power command also increases, and the system frequency fed back to the isolated operation detection device 1 further increases (or decreases) by the action of positive feedback. To do. Thus, the frequency change of the local system is increased so as to show a divergence tendency on the positive side (or the negative side) at the time of shifting to the single operation. For this reason, in the frequency feedback method, even if the power generation amount of the distributed power source and the load amount in the local system are balanced, the isolated operation is substantially fast based on a very small frequency (period) deviation. Detected.

The isolated operation detection device 1 may be further configured to detect an isolated operation from a change in the system voltage detected by the voltage detector 208.
When the isolated operation is detected, the isolated operation detection device 1 outputs a disconnection signal to the inverter-side switch 205. The inverter side switch 205 is turned off according to the disconnection signal, and the distributed power source composed of the interconnected inverter 2 and the DC power source 3 is disconnected from the local system. Thus, the independent operation of the interconnection inverter 2 is stopped.

  As described above, the isolated operation detection device 1 detects an isolated operation by detecting a change in system information (for example, system cycle) corresponding to an active signal command (for example, reactive current command). However, in such an existing active system, fluctuations in system information caused by output of distributed power supply, load fluctuations, system faults, etc. may be erroneously detected as changes caused by the occurrence of isolated operation. Therefore, in order to reduce erroneous detection of an isolated operation, the isolated operation detection device 1 is further configured as described below.

  FIG. 2 is a diagram illustrating a first configuration example of the isolated operation detection device according to the embodiment. FIG. 3 is a flowchart of a first example of the isolated operation detection method according to the embodiment. The isolated operation detection method shown in FIG. 3 is repeatedly executed by the isolated operation detection device 1 after the interconnection inverter 2 is connected to the system, for example.

  As shown in FIG. 2, the isolated operation detection device 1 includes an erroneous detection prevention unit 11 and an isolated operation detection unit 12. The erroneous detection prevention unit 11 and the isolated operation detection unit 12 are, for example, a processor such as a CPU (Central Processing Unit) or a DSP (Digital Signal Processor), an FPGA (Field Programmable Gate Array), or a PLD (Programmable Logic Device).

  The erroneous detection preventing unit 11 prevents erroneous detection of the isolated operation of the grid-connected inverter 2 due to the change in system information caused by the output of the distributed power source and the load fluctuation. The erroneous detection prevention unit 11 includes a command detection unit 111, an edge detection unit 112, an activation signal generation unit 113, and an isolated operation determination unit 114.

  The command detection unit 111 detects an active signal command exceeding a predetermined threshold (step S1). For example, when the isolated operation detection device 1 is configured to support the frequency feedback system, the detected active signal command is a reactive current command (or reactive power command). When the active signal command is a digital signal such as 1 (with an active signal command) or 0 (without an active signal command), the erroneous detection preventing unit 11 may not include the command detecting unit 111.

The edge detector 112 detects the rising edge of the detected active signal command (step S2).
The activation signal generation unit 113 generates an activation signal that activates the detection of the isolated operation of the grid-connected inverter 2 according to the system information detected from the system from the active signal command (step S3). Specifically, the enabling signal generation unit 113 generates an enabling signal at the detection timing of the rising edge of the active signal command. For example, when the isolated operation detection device 1 is configured to support the frequency feedback method, the system information used for detecting the isolated operation is a system cycle (or system frequency).

  The isolated operation determination unit 114 determines the presence / absence of the isolated operation of the interconnection inverter 2 from the isolated operation detection signal and the activation signal before the erroneous detection prevention process, and outputs the isolated operation detection signal after the erroneous detection prevention process according to the determination result. Output (step S4). The isolated operation detection signal before the erroneous detection prevention process is output from the isolated operation detection unit 12 in accordance with the system information detected from the system.

  The isolated operation detection unit 12 determines whether or not the connected inverter 2 is operated independently using an existing active method. For example, when the isolated operation detection device 1 is configured to support the frequency feedback method, the isolated operation detection unit 12 determines the presence or absence of the isolated operation using the frequency feedback method. The isolated operation detection unit 12 outputs an isolated operation detection signal according to the determination result to the isolated operation determination unit 114.

  FIG. 2 shows an example in which the erroneous detection prevention unit 11 and the isolated operation detection unit 12 are configured as an integrated device, but the erroneous detection prevention unit 11 and the isolated operation detection unit 12 are separate devices. It may be configured as. In such a configuration, the device corresponding to the isolated operation detection unit 12 may be an existing device that detects an isolated operation using an existing active method. According to such a configuration, by combining a device corresponding to the false detection prevention unit 11 with an existing device corresponding to the single operation detection unit 12, a device similar to the single operation detection device according to the embodiment is connected to the interconnection inverter 2. Can be easily implemented.

  In order to facilitate understanding of the islanding operation detection method executed by the islanding operation detection apparatus 1 shown in FIG. 2, an active signal command, an activation signal, system information, and an islanding operation detection signal will be described as examples. FIG. 4 is a diagram illustrating a first example of an active signal command, an enabling signal, system information, and an isolated operation detection signal. FIG. 4 shows an example of each signal when the isolated operation detection device 1 is configured to always support the reactive power fluctuation method. The reactive current command shown in FIG. 4 is an example of an active signal command. Yes, the periodic deviation shown in FIG. 4 is an example of system information.

  The reactive current command shown in FIG. 4 is a signal that is output to the coordinate converter 210 and also input to the command detection unit 111. The enabling signal generation unit 113 generates the enabling signal shown in FIG. 4 from the reactive current command. In the example shown in FIG. 4, the validation signal is a one-shot pulse that is activated at the detection timing of the rising edge of the active signal command. The pulse width of the one-shot pulse is equal to or smaller than the pulse width of the active signal command, and may be arbitrarily set according to the frequency of erroneous detection of isolated operation. For example, the pulse width of the enabling signal may be set narrow when the frequency of erroneous detection of isolated operation is high, and the pulse of the enabling signal may be set when the frequency of erroneous detection of isolated operation is low. The width may be set wide.

  The cycle deviation shown in FIG. 4 is a deviation of the system cycle detected from the system in which the reactive current according to the reactive current command is injected from the interconnection inverter 2. In addition to the periodic deviation detected in response to the reactive current command, the periodic deviation shown in FIG. 4 is caused by system disturbance due to output of other distributed power sources connected to the higher level of the system, load fluctuations, and the like. Periodic deviation is mixed. Specifically, in the example shown in FIG. 4, the waveform of the periodic deviation changes in response to the reactive current command after time t2, but before the time t2, it changes to the reactive current command due to system disturbance. It changes irregularly without responding. In the example shown in FIG. 4, the time t2 is the time when the independent operation of the interconnection inverter 2 is started.

  At time t3, time t4, and time t5 after time t2, the periodic deviation changes according to the reactive current injected into the system in accordance with the reactive current command, so that a detection level that serves as a reference for detecting isolated operation Over. Therefore, as shown in FIG. 4, at time t3, time t4, and time t5, the isolated operation detection unit 12 outputs an isolated operation detection signal (before erroneous detection prevention processing) indicating that the isolated operation has been detected. To do.

  The isolated operation determination unit 114 determines the presence or absence of an isolated operation by taking the logical product of the validation signal and the isolated operation detection signal (before erroneous detection prevention processing). Then, the isolated operation determination unit 114 outputs an isolated operation detection signal (after the erroneous detection prevention process) obtained by the logical product as a determination result. As shown in FIG. 4, as a result of the logical product of the activation signal and the isolated operation detection signal (before erroneous detection prevention processing), the isolated operation detection signal indicating that no isolated operation is detected at time t3. (After erroneous detection prevention processing) is output. However, at time t4 and time t5 after time t3, an isolated operation detection signal (after erroneous detection prevention processing) that correctly indicates that the isolated operation has been detected is output.

  On the other hand, at time t1 prior to time t2, the periodic deviation changes irregularly due to system disturbance, and thus exceeds a detection level that is a reference for detecting isolated operation. For this reason, at time t1, the isolated operation detection unit 12 erroneously detects isolated operation and outputs an isolated operation detection signal (before erroneous detection prevention processing) indicating that the isolated operation has been detected.

  The isolated operation determination unit 114 outputs an isolated operation detection signal (after the erroneous detection prevention process) obtained by ANDing the activation signal and the isolated operation detection signal (before the erroneous detection prevention process). As shown in FIG. 4, as a result of the logical product of the activation signal and the isolated operation detection signal (before erroneous detection prevention processing), an isolated operation detection signal ( (After false detection prevention processing) is not output.

  In this way, the enabling signal becomes valid (a flag is set) based on the timing at which the interconnection inverter 2 outputs the active signal. For this reason, in the isolated operation detection method according to the embodiment, only the response on the system side to the active signal output from the interconnection inverter 2 is evaluated. When both the isolated operation detection signal (before erroneous detection prevention processing) and the activation signal become valid (a flag is set), the isolated operation of the grid-connected inverter 2 is detected. Therefore, even if the system information is disturbed by the output of the distributed power source including self and others, load fluctuations, etc., and the isolated operation detection function according to the existing active method erroneously detects isolated operation, it is effective. No isolated operation is detected unless the activation signal is valid. Therefore, according to the isolated operation detection method according to the embodiment, erroneous detection of isolated operation can be reduced.

  For example, in the existing active method for detecting the isolated operation, the detected instantaneous value of the system information is directly used for determining whether or not the isolated operation is performed, so that there is a risk that the erroneous detection of the isolated operation occurs as described above. Further, for example, in the isolated operation determination method as described in Patent Document 1, the presence or absence of isolated operation is determined based on the detected system cycle, so that there is still a possibility of erroneous detection of isolated operation. . On the other hand, in the isolated operation detection method according to the embodiment, in addition to the system information, the corresponding active signal command is used to determine whether or not the isolated operation is performed, and only the response on the system side to the active signal output by the interconnection inverter is obtained. Be evaluated. For this reason, according to the isolated operation detection method according to the embodiment, erroneous detection of isolated operation can be reduced. In addition, according to the isolated operation detection method according to the embodiment, the erroneous detection prevention process according to the embodiment can be easily added to the isolated operation detection process according to the existing active method. Therefore, the isolated operation detection method according to the embodiment has a special effect even when compared with the existing active method or the like.

Note that the isolated operation detection method executed by the isolated operation detection device 1 is not limited to the above-described process, and may include a process in which the above-described process is changed or an additional process.
For example, the isolated operation detection device 1 may be changed from the configuration shown in FIG. 2 to the configuration shown in FIG. Further, the isolated operation detection method according to the embodiment may be changed from the process shown in FIG. 3 to the process shown in FIG. FIG. 5 is a diagram illustrating a second configuration example of the isolated operation detection device according to the embodiment. FIG. 6 is a flowchart of a second example of the isolated operation detection method according to the embodiment.

  As shown in FIG. 5, the isolated operation detection device 1 includes a false detection prevention unit 13 instead of the false detection prevention unit 11. The erroneous detection prevention unit 13 includes a signal inversion unit 131 and a detection invalidation unit 132 in place of the isolated operation determination unit 114. Moreover, as shown in FIG. 6, the isolated operation detection method performed by the isolated operation detection device 1 includes step S4 ′ instead of step S4.

  FIG. 5 shows an example in which the erroneous detection prevention unit 13 and the isolated operation detection unit 12 are configured as an integrated device, but the erroneous detection prevention unit 13 and the isolated operation detection unit 12 are separate devices. It may be configured as.

  The signal inversion unit 131 inverts the input validation signal and outputs an invalidation signal. The detection invalidation unit 132 invalidates the system information (before erroneous detection prevention processing) detected from the system using an invalidation signal, and outputs the invalidated system information (after erroneous detection prevention processing) to the isolated operation detection unit 12. (Step S4 '). The isolated operation detection unit 12 determines the presence or absence of an isolated operation from the input system information (after the erroneous detection prevention process) using an existing active method, and an isolated operation detection signal (an erroneous detection prevention process) according to the determination result. After) is output.

  In order to facilitate understanding of the islanding operation detection method executed by the islanding operation detection apparatus 1 shown in FIG. 5, the active signal command, the enable signal, the invalidation signal, the system information, and the islanding operation detection signal will be described as examples. To do. FIG. 7 is a diagram illustrating a second example of the active signal command, the enabling signal, the system information, and the isolated operation detection signal. In FIG. 7, a reactive current command having the same waveform as the reactive current command shown in FIG. 4 is shown as an example of the active signal command, and the cyclic deviation having the same waveform as the cyclic deviation shown in FIG. 4 (before erroneous detection prevention processing). Is shown as an example of system information.

  The enabling signal generation unit 113 generates an enabling signal as shown in FIG. 7 from the reactive current command. In the example illustrated in FIG. 7, the waveform of the reactive current command input to the validation signal generation unit 113 is the same as the waveform of the reactive current command illustrated in FIG. 4, and thus the same waveform as the validation signal illustrated in FIG. 4. The enabling signal is generated.

  The signal inverting unit 131 inverts the input enabling signal and outputs an invalidating signal as shown in FIG. The detection invalidation unit 132 invalidates the period deviation detected from the system (before erroneous detection prevention processing) by an invalidation signal, and outputs the invalidated period deviation (after erroneous detection prevention processing) to the isolated operation detection unit 12. To do. As shown in FIG. 7, the period deviation (after the erroneous detection prevention process) is set to 0 in the period in which the invalidation signal is valid (the flag is set) by the invalidation process.

The isolated operation detection unit 12 determines whether or not an isolated operation is performed according to the periodic deviation (after the erroneous detection prevention process), and outputs an isolated operation detection signal (after the erroneous detection prevention process) according to the determination result.
At time t1 shown in FIG. 7, the period deviation (before erroneous detection prevention processing) exceeds the detection level due to system disturbance. For this reason, if it is determined whether or not an isolated operation is performed according to the cycle deviation (before the erroneous detection prevention process), an isolated operation detection signal indicating that the isolated operation has been detected is erroneously output at time t1. However, in the invalidation process, the portion exceeding the detection level due to the system disturbance is masked by the invalidation signal obtained by inverting the validation signal. For this reason, as shown in FIG. 7, when it is determined whether or not an isolated operation is performed according to the periodic deviation (after the erroneous detection prevention process), an isolated operation detection signal (an erroneous detection prevention process) indicating that the isolated operation has been detected. After) is not output at time t1.

  In this way, a section for enabling the enabling signal for a while is provided based on the timing at which the interconnected inverter outputs the active signal, and the invalidating signal that is the inverted signal is valid when the enabling section for the enabling signal ends. (The flag is set and the mask is valid). For this reason, in the isolated operation detection method according to the embodiment, only the response on the system side to the active signal output from the interconnection inverter is evaluated. When the cycle deviation (before erroneous detection prevention processing) exceeds the predetermined detection level and the invalidation signal becomes invalid (the flag is not set and the mask is invalid), the independent operation of the interconnection inverter is detected. Is done. For this reason, even if system information is disturbed due to output of distributed power sources including self and others, load fluctuations, etc., unless the invalidation signal is invalid (the flag is not set and the mask is invalid), The islanding detection function according to the active method does not detect islanding. Therefore, according to the isolated operation detection method according to the embodiment, erroneous detection of isolated operation can be reduced.

  As described above, an example of the isolated operation detection method executed by the isolated operation detection device 1 has been described. However, the isolated operation detection method according to the embodiment can also be implemented by a computer that executes an isolated operation detection program in which each process performed by the isolated operation detection device 1 is regulated.

  FIG. 8 is a diagram illustrating a configuration example of a computer that executes the isolated operation detection program according to the embodiment. In the example illustrated in FIG. 8, the computer 7 includes a CPU 71, a main storage device 72, an auxiliary storage device 73, an input device 74, a display device 75, a storage medium driving device 76, and a communication interface 77. These units 71 to 77 included in the computer 7 are connected to each other via a bus 78.

  For example, the isolated operation detection program according to the embodiment is recorded in advance on a portable storage medium. Examples of the portable storage medium include a magnetic disk, an optical disk, a magneto-optical disk, and a flash memory. The isolated operation detection program recorded in the portable storage medium is read by the storage medium driving device 76 and installed in the auxiliary storage device 73. Alternatively, for example, the isolated operation detection program according to the embodiment is stored in advance in another computer (not shown) and installed in the auxiliary storage device 73 via the communication interface 77.

The CPU 71 reads the isolated operation detection program from the auxiliary storage device 73 to the main storage device 72 and executes the read isolated operation detection program.
Note that the input device 74 is, for example, a keyboard, a mouse, or a touch panel. The display device 75 is, for example, a liquid crystal display.

When the computer executes the isolated operation detection program according to the embodiment, the same effect as described above can be obtained.
The embodiment of the present invention described above is merely an example of a preferred embodiment of the present invention, and the present invention is not limited to this. Various modifications can be made to the above-described embodiment without departing from the spirit of the present invention. It is possible to add a modification.

DESCRIPTION OF SYMBOLS 1 Isolated operation detection apparatus 11, 13 False detection prevention part 111 Command detection part 112 Edge detection part 113 Validation signal generation part 114 Independent operation determination part 131 Signal inversion part 132 Detection invalidation part 12 Independent operation detection part 2 Interconnection inverter 201 Inverter circuit 202 AC reactor 203 Current detector 204 Capacitor 205 Inverter side switch 206 Instrument transformer 207 Period detector 208 Voltage detector 209 Reference signal generation circuit 210 Coordinate converter 211 Output current control circuit 212 Gate signal generation circuit 3 DC Power supply 4 Load 5 System power supply 6 System side circuit breaker 7 Computer 71 CPU
72 Main storage device 73 Auxiliary storage device 74 Input device 75 Display device 76 Storage medium drive device 77 Communication interface 78 Bus

Claims (5)

A command detection unit that detects an active signal command that is a reactive current command or reactive power command that exceeds a predetermined threshold with respect to an active signal injected from the interconnection inverter to the system,
Enabling signals to enable to detect the islanding operation of the interconnection inverter according to the detected line information from the line, and enabling signal generator for generating from the active command signals detected by the instruction detecting unit ,
An isolated operation detection unit including: an isolated operation detection unit that determines whether or not the isolated operation is performed from the isolated operation detection signal detected according to the system information and the validation signal, and outputs the isolated operation detection signal according to the determination result. apparatus. An edge detection unit for detecting an upstream edge of the active signal command;
The islanding operation detection device according to claim 1 , wherein the activation signal generation unit generates a one-shot pulse activated at a timing when the rising edge is detected as the activation signal. The isolated system information detected from the system is invalidated by an invalidation signal obtained by inverting the validation signal, and the invalidated system information is detected according to the system information. isolated operation detecting apparatus according to claim 1 or 2 comprising, instead of the detection invalidating unit for outputting to the isolated operation determination unit. Detects an active signal command that is a reactive current command or reactive power command exceeding a predetermined threshold for an active signal injected from the interconnection inverter into the system,
Enabling signals to enable to detect the islanding operation of the interconnection inverter according to the detected line information from the line, to generate from the detected the active command signals,
An isolated operation detection method for determining the presence or absence of the isolated operation from the isolated operation detection signal detected according to the system information and the validation signal, and outputting the isolated operation detection signal according to the determination result. Detects an active signal command that is a reactive current command or reactive power command exceeding a predetermined threshold for an active signal injected from the interconnection inverter into the system,
Enabling signals to enable to detect the islanding operation of the interconnection inverter according to the detected line information from the line, to generate from the detected the active command signals,
An isolated operation detection program for determining whether or not the isolated operation is performed from the isolated operation detection signal detected according to the system information and the validation signal, and causing the computer to execute a process of outputting the isolated operation detection signal according to the determination result .

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