JP4139756B2 - Isolated operation prevention device, isolated operation prevention system, and isolated operation prevention equipment - Google Patents

Description

  The present invention relates to an isolated operation preventing device provided corresponding to each of the distributed power supplies in order to detect the isolated operation state of the distributed power supply system in which a plurality of distributed power supplies are linked by an active method, and The present invention relates to an isolated operation prevention system for a distributed power supply system configured by a combination of the isolated operation prevention devices, and an isolated operation prevention facility for integrated control of the isolated operation prevention system for a plurality of distributed power supply systems.

  The isolated operation prevention device provided in correspondence with such a distributed power source generates a reverse power flow that sends the power generated by the distributed power source such as a photovoltaic power generation facility or a cogeneration facility connected to the power system to the power system. In the case where an accident occurs in the power system and a part of the power system is disconnected, the state where power supply continues with the connected distributed power source in the disconnected power system, that is, an independent operation It is for detecting the state and disconnecting the distributed power source. In the present invention, a power system connected to a distributed power source that is disconnected when the power system is abnormal is defined as a distributed power system. In other words, the distributed power supply system is not limited to a single consumer provided with a distributed power supply, but may be a power system in which a plurality of consumers each provided with a distributed power supply are connected. is there.

  The isolated operation prevention device provided corresponding to such a distributed power supply uses an active method as a method for detecting an isolated operation state. In this active method, reactive power or active power output to a distributed power system connected to a distributed power source is intentionally (that is, actively) changed, and the distributed power system is powered. It is determined that the vehicle is in the single operation state by detecting the influence of fluctuations such as reactive power or active power that appears prominently when disconnected from the system.

  By the way, when each of the isolated operation prevention devices provided corresponding to each of the plurality of distributed power supplies outputs a variation such as reactive power or active power to the distributed power system separately, the plurality of output fluctuation components There is a problem that the (variable waveform) is canceled out by mutual interference, making it difficult to detect the isolated operation state. In view of such a problem, a configuration has been proposed in which reactive power or active power fluctuations are performed in synchronization with each other by each isolated operation prevention device (see, for example, Patent Document 1 and Patent Document 2).

  The device described in Patent Document 1 is provided with a power fluctuation means connected to a load via a switch in an isolated operation prevention device installed in a distributed power source connected to a distribution system, and is drawn into the distributed power source. A detector is installed that can monitor the voltage and current on the wire. Then, by switching the switch on and off at a predetermined timing, an intentional load fluctuation is created in the distributed power supply system in which the distributed power supplies are interconnected. At that time, by synchronizing the switching timing of switching on and off in the isolated operation prevention devices installed in a plurality of distributed power sources based on the time signal or the time signal or the system power source frequency, the active interference of them can be achieved by mutual interference. Trying to avoid the signal being canceled.

  Patent Document 2 describes a phase of a periodic variation of reactive power supplied from a grid interconnection inverter of a distributed power source and a periodical variation of reactive power supplied from a grid interconnection inverter of another distributed power source. Are synchronized with each other based on time information transmitted from a GPS satellite, so that mutual interference of fluctuation components of reactive power by the isolated operation prevention device is prevented, and isolated operation is detected.

Japanese Patent No. 3029185 JP-A-9-74684

  The isolated operation prevention device described in Patent Document 1 is intended to prevent mutual interference by adjusting the timing of load application based on time information or system frequency obtained from radio waves, telephone lines, or the like.

  However, if time information cannot be obtained continuously due to the reception status or line status, or if the acquisition interval is long, an internal pulse circuit will determine the timing of loading the load, resulting in an error and time. As the time elapses, a shift occurs in the timing of loading the load for each isolated operation prevention device.

  In addition, when obtaining time information using a telephone line or the like, it is necessary to obtain time information continuously for the above reasons, so a usage fee for continuing to use the telephone line is required and the running cost is high. There is a problem of becoming.

  In addition, when adjusting the timing of loading the load based on the system frequency, it can be realized if the loading is performed every cycle of the system frequency, but when it is performed at a rate of once every plural cycles of the system frequency. In addition, when performing load input over multiple cycles, or in the isolated operation detection method and reactive power fluctuation method that are not considered in this patent, it is impossible to match the timing with only the system frequency, so mutual interference Cannot be avoided.

  Patent Document 2 describes a variation pattern of reactive power given to each of a plurality of distributed power supply isolated operation prevention devices by using time information given by GPS or the like at a plurality of distributed power supplies at the same time. However, since the phases are adjusted so as to have the same phase, the object is to detect the isolated operation state by avoiding interference between the reactive power fluctuation components of the isolated operation preventing devices.

  However, the reactive power fluctuation is obtained by changing the reactive current in the grid interconnection inverter. Therefore, the isolated operation preventing device described in Patent Document 2 is connected to the system impedances 23a and 23b as shown in FIG. When the transformer 24 is installed in each of a plurality of distributed power sources (customers 10a, 10b, 10c) linked to the power distribution system 2 existing in each place, power is distributed from each of the customers 10a, 10b, 10c. The reactive current fluctuation component output to the system 2 is out of phase by the system impedances 23a and 23b and the transformer 24. Therefore, depending on the reactive current injection method, it is output by each of the customers 10a, 10b, and 10c. Even if the reactive currents have the same phase, at certain points in the distribution system 2, they are To each other, there is a problem that the detection of the islanding operation state becomes difficult.

  In addition, depending on the method of the isolated operation prevention device, there is a method that uses a voltage change pattern, and therefore, it may be impossible to apply this patent based only on time information.

  Furthermore, the isolated operation prevention device described in Patent Document 2 is configured to repeat the adjustment of the reactive power phase by the isolated operation prevention devices of a plurality of distributed power sources based on received time information. When GPS is used as the time information, when the isolated operation prevention device is installed in the basement, the use range is restricted, such as being unable to receive the time information from the GPS and using it.

  In addition, the method described above is based on the premise that the reactive power and active power fluctuation patterns of all the isolated operation prevention devices are matched, so the number of distributed power sources and isolated operation prevention devices connected to the power system When there are many, there is a concern about the influence of fluctuations in reactive power, active power, etc. by the isolated operation prevention device in a normal power system in which no power failure occurs.

  The present invention has an advantageous configuration in terms of implementation, minimizes the influence of power fluctuations caused by active signals on the power system, prevents active signals fluctuated by a plurality of isolated operation prevention devices from interfering with each other, and maintains an isolated operation state. The point is to enable proper detection.

In order to achieve this object, the first characteristic configuration of the isolated operation preventing apparatus according to the present invention is to detect an isolated operation state of a distributed power system in which a plurality of distributed power sources are linked in an active manner. An isolated operation prevention device provided corresponding to each of the distributed power sources, and used to detect an isolated operation state, the periodic active signal that varies with the passage of time is used for the distributed power system. An active signal generating / injecting means for generating the active signal based on periodic time information different from the voltage waveform of the power supply and injecting the active signal into the output control unit of the distributed power supply or injecting into the distributed power supply system; Time information obtaining means for obtaining information, correction time determining means capable of determining a correction time of the active signal based on the time information obtained by the time information obtaining means, and a voltage waveform of the distributed power system Monitoring That the monitoring means and is provided, the active signal generating and injection means, wherein after the first correction injection timing of the active signal in the corrected time determined by the correction time determination means, the correction time determination means Or the correction timing of the active signal is re- corrected based on the number of voltage cycles of the voltage waveform monitored by the monitoring means.

According to the first characteristic configuration, the active signal generating / injecting means generates a periodic active signal that varies with time based on periodic time information different from the voltage waveform of the distributed power supply system. Generated and configured to perform the initial correction of the injection timing of the active signal at the correction time determined by the correction time determination means, or injected into each of the output control units of the plurality of distributed power sources or the distributed type a plurality of active signals respectively injected into the power supply system now to synchronize, then the correction time is determined by the correction time determining means, or to repeat the re-correction of the injection timing of the active signal on the basis of the number of voltage cycles Therefore, even when the time information cannot be obtained over a long period of time by the time information acquisition means, the timing of injecting the active signal to the distributed power supply system Correction is ongoing. As a result, it is possible to prevent the active signals from being canceled out by interference and to be able to detect the isolated operation state of the distributed power supply system satisfactorily. And, when each of the isolated operation prevention devices provided corresponding to the plurality of distributed power sources connected to the distributed power supply system is a single isolated operation prevention device, Even when the methods of driving prevention devices are different from each other, the correction time determination means arbitrarily sets the correction time of the active signal output from the active signal generation / injection means, and the active signals are canceled by interference. Thus, the isolated operation state of the distributed power supply system can be detected well.
Furthermore, for a single isolated operation prevention system, the correction time can be set to the same time, and the active signal can be synchronized, and the correction time can be intentionally shifted as necessary. It is also possible to reduce the influence on the distributed power system. In addition, even when the time information cannot be obtained over a long period of time, the active operation is injected from each isolated operation preventing device into each of the output control units of the plurality of distributed power sources or into the distributed power system. The signal can be prevented from being canceled by interference, and the isolated operation state of the distributed power supply system can be detected satisfactorily.

In order to achieve this object, the second feature configuration of the isolated operation preventing apparatus according to the present invention is to detect the isolated operation state of a distributed power system in which a plurality of distributed power sources are linked in an active manner. An isolated operation prevention device provided corresponding to each of the distributed power sources, and used to detect an isolated operation state, the periodic active signal that varies with the passage of time is used for the distributed power system. An active signal generating / injecting means for generating the active signal based on periodic time information different from the voltage waveform of the power supply and injecting the active signal into the output control unit of the distributed power supply or injecting into the distributed power supply system; Time information obtaining means for obtaining information, correction time determining means capable of determining a correction time of the active signal based on the time information obtained by the time information obtaining means, and a voltage waveform of the distributed power system Monitoring And the active signal generating / injecting means monitors the voltage waveform monitored by the monitoring means immediately after the correction time determined by the correction time determining means. After the initial correction of the injection timing of the active signal in order to match the specific phase of the voltage waveform, at the correction time determined by the correction time determining means, or the voltage waveform monitored by the monitoring means The configuration is such that re-correction of the injection timing of the active signal is repeated based on the number of voltage cycles .

According to the second characteristic configuration, when the active signal generation / injection means uses a voltage waveform, the monitoring means immediately after the correction time in which the specific phase of the active signal is determined by the correction time determination means The initial correction of the injection timing of the active signal is performed so as to match the specific phase of the voltage waveform monitored by, thereby avoiding the cancellation of the active signal due to interference, and the isolated operation state of the distributed power system is good It can be set as a structure detected by (1). After that, it is configured to repeat the re-correction of the active signal injection timing based on the correction time determined by the correction time determining means or based on the number of voltage cycles. Even if it cannot be obtained over a long period of time, the correction of the injection timing of the active signal to the distributed power supply system is continuously performed. As a result, even when the time information cannot be obtained over a long period of time, the active signals injected from the individual operation prevention devices are not canceled by interference, and the single operation state of the distributed power system is excellent. It can be configured such that it is detected. And, when each of the isolated operation prevention devices provided corresponding to the plurality of distributed power sources connected to the distributed power supply system is a single isolated operation prevention device, Even when the methods of driving prevention devices are different from each other, the correction time determination means arbitrarily sets the correction time of the active signal output from the active signal generation / injection means, and the active signals are canceled by interference. Thus, the isolated operation state of the distributed power supply system can be detected well.
Furthermore, for a single isolated operation prevention system, the correction time can be set to the same time, and the active signal can be synchronized, and the correction time can be intentionally shifted as necessary. It is also possible to reduce the influence on the distributed power system.

The third characteristic feature of the islanding prevention device according to the present invention, in addition to the second feature structure, lies in a particular phase of the voltage waveform is a phase of the phase or peak point of the zero-crossing point.

According to the third characteristic configuration, the specific phase of the voltage waveform can be reliably specified by the phase of the zero crossing point or the peak point of the voltage waveform, so that the correction of the injection timing of the active signal is uniform. Can be implemented automatically.

The fourth characteristic feature of the islanding prevention device according to the present invention, in addition to the second or third characterizing feature, specific phase zero-crossing point of the active signal, the peak point, the rising point or falling point of the phase There is a point.

According to the fourth characterizing feature, the particular phase of the active signal, the zero-crossing point, the peak point, the rising point, can be reliably identified in the falling point phase, image correction of injection timing of the active signal It can be implemented unilaterally.

According to a fifth feature configuration of the isolated operation prevention apparatus according to the present invention, in addition to any of the first to fourth feature configurations described above, the time information obtaining unit includes information on a standard time that is transmitted after being modulated into a radio wave. The time information is received and generated.

According to the fifth characteristic configuration, the time information is created with reference to the information about the standard time that is transmitted after being modulated into radio waves. Therefore, when the time information acquisition means is installed outdoors, In addition to being able to receive well, it is possible to receive the radio wave even when installed indoors, so that the injection timing of the active signal can be reliably corrected based on the time information.

The sixth feature configuration of the isolated operation prevention device according to the present invention includes, in addition to any of the first to fourth feature configurations, information related to standard time transmitted by the time information obtaining unit via the communication network. The time information is received and generated.

According to the sixth characteristic configuration described above, it is created with reference to information on standard time transmitted via a communication network such as the Internet or a public telephone line. For example, if there is a communication facility such as a modem, information on standard time is provided. Therefore, it is possible to reliably correct the injection timing of the active signal based on the time information.

In order to achieve this object, the seventh characteristic configuration of the isolated operation prevention system according to the present invention is to detect an isolated operation state of a distributed power system in which a plurality of distributed power sources are linked by an active method. An isolated operation prevention system provided with a plurality of isolated operation prevention devices provided corresponding to each of the distributed power sources, wherein each of the plurality of isolated operation prevention devices includes the first to sixth characteristic configurations. It is the point which is comprised so that the said independent operation state may be detected by the active system in any one of.

According to the seventh feature configuration, the isolated operation prevention device having any one of the first to sixth feature configurations or a plurality of feature configurations is linked to one distributed power supply system. Of course, when the plurality of islanding prevention devices provided corresponding to each of the distributed power sources is the islanding prevention device having the same configuration, the islanding operation prevention devices having different configurations can be used to Even if it is configured to detect the isolated operation state, it is ensured that the isolated operation state is generated in the distributed power supply system by setting the appropriate time with the correction time determination means of each isolated operation prevention device. Can be detected.

The eighth characteristic configuration of the isolated operation prevention system according to the present invention is that a distributed power source provided with an internal time information type or external time input type isolated operation prevention device is further linked to the distributed power system. is there.

According to the eighth feature configuration, the plurality of islanding prevention devices constituting the islanding prevention system described in the seventh feature configuration first detect the islanding state, and these islanding prevention devices are provided. The distributed power source provided with the internal time information type or external time information input type isolated operation prevention device connected to the same distributed power source system after the distributed power source is disconnected or output stopped, A configuration in which a plurality of distributed power sources are disconnected or output is overloaded, and a single operation state of the distributed power source system can be detected satisfactorily.

According to a ninth feature configuration of the isolated operation prevention facility according to the present invention, the isolated operation prevention system according to the seventh or eighth feature configuration is provided in each of the plurality of distributed power systems, and the plurality of distributed power systems. The correction time determination means of the isolated operation prevention device in each of the plurality of distributed power supply systems is configured to arbitrarily determine the correction time in each of the plurality of distributed power systems.

According to the ninth characteristic configuration, the active signal injected from the active signal generating / injecting means of the isolated operation prevention device provided corresponding to the plurality of distributed power sources connected to the distributed power source system. The same correction time can be set so that the fluctuation does not cause mutual interference in one distributed power supply system, and a correction time different from the correction time in other distributed power supply systems is set. As a result, in one distributed power system, the active signals injected from the individual operation prevention devices do not cancel each other due to interference, so that the isolated operation state of the distributed power system can be detected well. In addition, by properly setting the correction time for each distributed power supply system with other distributed power supply systems, the distributed power supply system can be set between the distributed power supply systems in a normal state. Since it becomes possible to cancel the active signals, it is possible to minimize the influence on the distributed power supply system caused by the active signals at all times.
When there are many distributed power supply systems, the correction time in one distributed power supply system and the correction time in another distributed power supply system can be the same. However, the correction times in all distributed power systems are not the same.

Hereinafter, an isolated operation prevention device, an isolated operation prevention system, and an isolated operation prevention facility according to the present invention will be described with reference to the drawings.
Illustrated in FIG. 1 is a schematic diagram of a power supply system from a power transmission system 1 to which a power plant or the like is connected to a customer 10a, 10b, 10c via a distribution substation 20. The distribution substation 20 includes a transformer 21 for adjusting the voltage and a substation circuit breaker 22 that is a switch capable of stopping the supply of power to the distribution system 2. Adjust to 6600 volts and send to distribution system (distributed power supply system) 2. In the customer 10a, the load device 11 and the power generation device (an example of a distributed power source) 12 are connected to the power distribution system 2 via the circuit breaker 13a, the circuit breaker 13b, and the circuit breaker 13c. An isolated operation preventing device 14 for preventing an isolated operation state of the power generation device 12 is provided. Further, the distribution system 2 includes system impedances 23a and 23b, a transformer 24 such as a pole transformer, and the like. In the present invention, a power system connected to a distributed power source that is disconnected by a circuit breaker when the power system is abnormal is defined as a distributed power system.

  In FIG. 1, the functional block diagram of only one customer 10a is drawn, but the load device 11, the power generation device 12, and the independent operation prevention device 14 are similarly applied to the other customers 10b and 10c. Is provided. Each of the isolated operation prevention devices 14 provided to prevent the isolated operation state of the power generation devices 12 of the consumers 10a, 10b, and 10c is supplied with a specific active signal that varies with time. Active signal generating / injecting means 17 for injecting or injecting power into the power distribution system 2, time information obtaining means 16 for obtaining time information, and time information obtained by the time information obtaining means A correction time determining means 18 for determining the correction time based on the above and a monitoring means 15 for monitoring the voltage waveform of the distribution system 2 are provided.

  Then, the substation circuit breaker 22 is opened due to an accident or the like, and the distribution system 2 downstream from the substation 20 is disconnected from the upstream transmission system 1. When the power generation output and the loads of all consumers connected to the power distribution system 2 are balanced and the power supply is continued by the power generation device 12, a single operation state is established. In this case, in order to avoid the problem of the quality of power supplied to the distribution system 2, the problem of electric shock in the distribution system 2, the problem of asynchronous input, etc., the customers 10a, 10b, 10c are the circuit breakers 13c. Or when the power generation device 12 has an inverse conversion function, it is necessary to disconnect the power generation device 12 from the distribution system 2 by a gate block or the like. For this purpose, when an isolated operation state occurs, the reactive power output from the isolated operation prevention device 14 to the distribution system 2 by the active signal injected into the output control unit of the power generation device 12 or injected into the distribution system 2 or It is necessary for fluctuations in active power or the like to appear as clearly as possible in the distribution system 2. In the present embodiment, the description about performing the disconnection of the power generation device 12 by detecting the variation of the reactive power or the active power in the distribution system 2 that clearly appears when the single operation state occurs Since it is the same as a general technique, it abbreviate | omits.

  The time information obtaining means 16 provided in each isolated operation prevention device 14 receives a standard radio wave transmitted from a standard radio wave transmission station with an antenna and obtains information on the standard time from the standard radio wave, or a GPS satellite. A modem is used for a device that receives information about the standard time from the radio wave, and a standard time supply system of the Communications Research Laboratory that manages Japanese standard time information. It can be realized by a device that connects and obtains information on the standard time, or a device that obtains information on the standard time from a time signal obtained through a public line using a communication device such as a modem. It should be noted that all the isolated operation prevention devices 14 included in the respective customers 10a, 10b, and 10c do not sequentially acquire information related to these standard times from the outside, but prevent a single reference time that is not standard time information from being isolated. A method is also possible in which the devices 14 communicate with each other via the time information acquisition means 16 to obtain a common reference time. The time information acquisition means 16 as described above is not a unique device, but can be additionally installed at a particularly low cost when it is a device that obtains information on standard time from standard radio waves. 14 does not become expensive.

  As the active signal generating / injecting means 17, an active signal that varies with time is injected into the output control unit of the power generation device 12 or injected into the distribution system 2 to vary the reactive power or active power of the distribution system 2, etc. Reactive power fluctuation method, reactive power compensation method, inter-order harmonic injection method, phase shift method, reactor type load fluctuation method, harmonic injection method, frequency shift method, active power fluctuation method, resistance type load fluctuation method, etc. There is. The active signal generating / injecting means 17 having various device configurations can be employed according to each method. For example, in the case of the reactive power fluctuation method, the active signal generation / injection means 17 sets the voltage setting value of an AVR circuit (not shown) functioning as the output control unit of the rotary power generation device 12 to a period of, for example, a crystal oscillator. In the case of the phase shift method, the active signal generating / injecting means 17 is a generator 12 that injects a periodic active signal generated based on typical time information and varies the reactive power of the power distribution system 2. This is a device that changes the reactive power of the distribution system 2 by changing the phase of the output current. Further, in the case of the load variation method, the active signal generating / injecting means 17 includes a load switching device capable of switching connection / disconnection of impedance (load) with respect to the power generation device 12 and switching between connection / disconnection of impedance. The power fluctuation by

<First Embodiment>
Illustrated in FIG. 3 is a diagram for explaining the operation processing flow of the time information acquisition means 16, the correction time determination means 18 and the active signal generation / injection means 17 provided in the isolated operation prevention device 14. In addition, the correction method of the injection | pouring timing of the active signal in the independent operation prevention apparatus 14 installed in the consumer 10a demonstrated below is the same also about the independent operation apparatus 14 installed in the other consumers 10b and 10c. In addition, the present invention can be applied to the isolated operation prevention apparatus using the various active methods described above. First, the time information obtaining unit 16 sequentially receives information about the standard time in Step 100. When the information about the standard time is received (in the case of “Yes” in the figure), the process proceeds to Step 102. When the information about the standard time is not received (in the case of “No” in the figure), the process 100 is performed. It is done repeatedly.

  Next, in step 102, the time information obtaining means 16 decodes the received information regarding the standard time. For example, when a standard radio wave transmitted from a standard radio station is received, the standard radio wave includes a time code such as second information and minute information. (For example, information indicating the minute) is taken out and transmitted to the correction time determination means 18. Thereafter, in step 104, the correction time determination means 18 sets the set correction time (the setting is 0:00 (0: 0), 0:02,..., 23:56, 23:58, 0: When the time is set to 00, 2:00,..., 22:00, etc., or when there is a case where the hour unit, the minute unit, the second unit, etc. are matched), the set delay A correction command is given to the active signal generation / injection means 17 after time (setting of phase 0 °, 10 °, 50 °, etc. for 0 msec or 1 msec, or 50/60 Hz of the system frequency).

  The active signal generating / injecting means 17 determines whether or not the correction command has been received in step 200 while injecting or injecting into the power distribution system 2 an active signal that fluctuates with time. If a correction command is received, the process proceeds to step 204. If a correction command is not received, step 200 is repeated. When the correction command is received, the active signal generating / injecting means 17 in the step 204, in order to synchronize the plurality of active signals injected into the output control unit of the power generator 12 or the distribution system 2, At the correction time (correction command reception timing) determined by the correction time determination means 18 based on the time information obtained by the time information acquisition means 16 provided for each, the phase or fluctuation timing of the active signal (active signal injection timing) ) To correct. At this time, the correction time and the delay time set in the correction time determination means 18 are the same in the same distributed power supply system for the single operation prevention device of the same system.

  For example, as shown in FIG. 2, the correction signal is determined by making the correction time and the delay time of the correction time determination means 18 the same in the same distributed type power supply system for the single operation prevention apparatus of the same system as shown in FIG. The active signal generation / injection means 17 in the same distributed power supply system corrects the injection timing of the active signal each time the signal is transmitted, and as a result, the synchronization of the active signals injected by the plurality of isolated operation prevention devices is performed. As a result, the power fluctuation caused by injecting the active signal does not interfere with each other in the same distributed power supply system, and the isolated operation is well detected.

Second Embodiment
Next, FIG. 4 is a diagram for explaining the operation processing flow of the time information acquisition means 16, the correction time determination means 18 and the active signal generation / injection means 17 provided in the isolated operation prevention device 14. Since the processing up to step 200 is the same as that described in the first embodiment, the description thereof is omitted.
In the second embodiment, following the step 200 of the first embodiment described with reference to FIG. 3, as shown in steps 202 to 212, the voltage waveform of the distribution system 2 monitored by the monitoring unit 15 is shown. Based on the number of voltage cycles, the active signal generating / injecting means 17 repeats the correction of the injection timing of the active signal to the distribution system 2. In this embodiment, in step 205, the specific phase of the active signal is matched with the zero cross point of the voltage waveform. This is affected by the voltage phase difference being different at each point in the distributed power system due to the transformers 24 such as the system impedances 23a and 23b and the pole transformers depending on the method and control method of the active signal generation / injection means 17. This is because the specific phase of the active signal needs to coincide with the specific phase of the voltage waveform in the isolated operation prevention apparatus using the case or the method using the voltage waveform, depending on the control method of other active signal generation / injection means As in the first embodiment, step 204 may be performed instead of step 202 and step 205.

  Specifically, after the active signal generating / injecting unit 17 matches the phase of the zero crossing point of the voltage waveform with the specific phase of the active signal in step 205, the active signal generating / injecting unit 17 in step 206 Set the zero cross point count to zero. Next, if the monitoring means 15 monitors the zero cross point of the voltage waveform of the distribution system 2 in step 208 and can detect one zero cross point, the active signal generating / injecting means 17 sets the count number of zero cross points to 1 in step 210. Increase the number. In step 212, the active signal generating / injecting means 17 determines whether or not the count number is equal to a predetermined set value.

  In step 212, when the count number of the zero cross point is equal to the predetermined set value, the process proceeds to step 202, and phase correction is performed on the specific phase of the active signal. On the other hand, if the count value of the zero cross point is not equal to the predetermined set value in step 212 (that is, smaller than the predetermined set value), the process proceeds to step 208 and the count of the zero cross point is continued. In other words, considering that the zero cross point appears in a cycle according to the voltage waveform of the power distribution system 2, it can be said that Steps 208 to 212 are equivalent to measuring a predetermined period. For example, when the set value of the count number as the end condition of the time measuring process is 600 and the frequency of the voltage waveform is 60 Hz, the predetermined period until the time measuring process ends is 5 seconds. As a result, after the active signal phase correction is performed in step 205, the re-correction of the specific phase of the active signal is repeated every 5 seconds (an example of a predetermined period) regardless of whether or not time information is received. become.

  For example, FIG. 5 is an image diagram when the reactive power fluctuation method, the harmonic injection method, or the like is applied as the method of the isolated operation detection device. As shown in the voltage waveform of the distribution system 2 in FIG. The zero crossing point of the waveform is monitored, and the active signal that fluctuates with the passage of time shown by the broken line in FIG. 5B (the solid line in FIG. 5B shows the instantaneous waveform of the current that appears as a result of injecting the active signal. Note that, in the harmonic injection method, the active signal indicated by the broken line is directly injected into the distributed power supply system), and the predetermined phase of the active signal is added to the phase of the zero cross point that appears immediately after the correction time. The injection timing of the active signal is corrected so as to match (here, the phase where the amplitude becomes zero). Specifically, although a phase shift occurs at time t3, in the present embodiment, when a correction command is received at time t2, the rising phase of the active signal is made to coincide with the phase of the zero cross point that appears immediately after the correction time. In addition, the reactive current output timing (active signal injection timing) is corrected. Here, the zero cross point includes a zero cross point when the amplitude changes from negative to positive and a zero cross point when the amplitude changes from positive to negative. In order to correct the phase of the active signal, The phase of any zero crossing point may be used, and the phase of a positive peak point, a negative peak point, a rising point, or a falling point can be used. It is necessary to make common in which phase each existing isolated operation prevention device 14 is matched. Furthermore, it is possible to correct the phase of the active signal using another phase in the voltage waveform of the distribution system 2.

  Further, FIG. 6 is an image diagram when a method using another voltage waveform is applied as the method of the isolated operation detection device. As shown in the voltage waveform of the distribution system 2 in FIG. As shown in the waveform of the active signal in FIG. 6B, the zero crossing point is monitored, and the active signal injection timing (here, the phase at which the active signal rises) is received at the correction command reception timing so as to synchronize the active signals. ) Has been corrected. Specifically, at time t10, the phase of the zero crossing point of the voltage waveform and the rising phase of the active signal are synchronized. However, when time elapses, a phase shift occurs as at time t11. However, in this embodiment, when a correction command is received at time t12, the injection timing of the active signal is corrected so that the rising phases of the active signal match at the reception timing of the correction command.

  Thus, according to the present embodiment, for example, only the time information of AM 0:00 once a day is acquired, and only the correction command based on this is transmitted, and the same distributed power source is used on that day. Within the grid, power fluctuations can be perfectly synchronized. As a specific method, the acquisition of time information is started when the built-in clock owned by the isolated operation detection device 14 becomes PM 11:55, and a correction instruction is transmitted by obtaining the time information of AM 0:00. You may end the acquisition of time information at the time. As a result, even when the time information is obtained using a telephone line or the like, the line connection time can be shortened, so that the line connection charge can be minimized.

<Third Embodiment>
Next, FIG. 7 is a diagram for explaining the operation processing flow of the time information acquisition means 16, the correction time determination means 18, and the active signal generation / injection means 17 provided in the isolated operation prevention device 14. Note that the processing up to step 206 is the same as that described in the second embodiment, and a description thereof will be omitted.
The third embodiment is characterized in that a correction command receiving step (step 207) is performed subsequent to step 206 of the second embodiment described with reference to FIG. Specifically, after the active signal generating / injecting means 17 sets the count value of the zero cross point to zero in step 206, it is determined whether or not the correction command is received in step 207. Then, when the correction command is received, the process proceeds to step 202, and correction is performed again to match the specific phase of the active signal with the specific phase of the voltage waveform of the distribution system 2. On the other hand, when the correction command is not received in step 207, the process proceeds to step 208, and the zero cross point is repeatedly counted. If the count value of the zero cross point is not equal to the predetermined set value, the process proceeds to step 207, and the active signal generating / injecting means 17 determines whether or not a correction command has been received. Although not shown here, since the cycle for receiving the correction command is different from the count cycle cycle of the zero cross point, there is a possibility of causing a kind of hunting. It is implemented only when it is not received within a certain time. That is, in the second embodiment, after receiving the correction command in step 200, based on the number of voltage cycles of the voltage waveform of the distribution system 2, the phase of the specific phase of the active signal with respect to the specific phase of the voltage waveform of the distribution system 2 In this embodiment, when the correction command is received through step 207 in the present embodiment, the same active signal phase correction as in step 205 is performed, and when the correction command is not received within a predetermined time. The rephase correction of the active signal is performed according to the number of voltage cycles.

<Fourth embodiment>
In the above embodiment, the isolated operation prevention device 14 installed in each of the customers 10a, 10b, and 10c existing in the same distributed power supply system has the same device configuration described in the first to third embodiments. However, in the present embodiment, an example in which the plurality of islanding prevention devices 14 constitute an islanding prevention system using the islanding operation prevention devices having a plurality of types of device configurations will be described. Specifically, the customers 10a and 10b employ an isolated operation prevention device having the same device configuration as that of the first embodiment, and the customer 10c employs an isolated operation prevention device of the same device configuration as that of the third embodiment. Think about the case.

In this case, in the isolated operation prevention device 14 installed in the customer 10c, when the correction command is received from the correction time determination means 18, the active signal generation / injection means 17 sends the active signal injected into the distribution system 2. In order to match the specific phase of the voltage waveform immediately after the correction time determined by the correction time determination means 18 based on the time information obtained by the time information acquisition means 16 provided in the isolated operation preventing device 14. It operates to correct the signal injection timing.
On the other hand, in the isolated operation preventing apparatus 14 installed in the consumers 10a and 10b, as in the first embodiment, when the correction command is received from the correction time determination means 18, the active signal generation / injection means 17 Correction time determined by the correction time determination means 18 based on the time information obtained by the time information acquisition means 16 provided in each of the isolated operation preventing devices 14 in order to synchronize a plurality of active signals injected into the power distribution system 2 The operation is performed so as to correct the injection timing of the active signal.
As a result, if the correction time by the correction time determination means 18 provided in each of the consumers 10a, 10b, and 10c is appropriately set, the rising phase of the active signal injected from the consumers 10a and 10b into the power distribution system 2 And the rising phase of the active signal injected into the power distribution system 2 from the customer 10c coincides with each other, so that when the single operation occurs, each power fluctuation caused by the active signal injected by each single operation prevention device in the distributed power supply system The added power fluctuation clearly appears, and the isolated operation state can be detected well.

<Fifth Embodiment>
In the first to fourth embodiments, the time information obtaining unit 16 is a device that obtains information on standard time from standard radio waves, a device that obtains information on standard time from radio waves from GPS satellites, or a Japanese standard. When using a device that obtains information about standard time from a standard time supply system that manages time information, or a device that obtains information about standard time from a time signal obtained via a public line using a communication device such as a modem In addition to the above, in addition to this, injection into the output control unit of the power generation device 12 based on internal time information by a built-in crystal resonator or a clock function or external time information obtained by another different method. Alternatively, an internal time information type active signal or an external time input type active signal configured to change the active signal injected into the power distribution system 2 over time. Adult-injection means 17 power generator 12 which islanding prevention device 14 is provided to correspond with the can may be interconnection to the power distribution system 2.
In this case, since it is assumed that the isolated operation prevention system described in the first to fourth embodiments is constructed, the isolated operation prevention described in the first to fourth embodiments is performed. Since active signals injected by the device do not cause mutual interference, islanding is well detected. Even if the isolated operation prevention device not according to the present invention is connected to this, the isolated operation preventing device described in the first to fourth embodiments provides a power generation device in which they are provided correspondingly. First, the isolated operation state or the other protective device not according to the present invention can immediately detect the isolated operation state, and as a result, all the power generation devices are disconnected from the distribution system 2. It will be.

<Sixth Embodiment>
In the first embodiment, the case where the distributed power system having the consumers 10a, 10b, and 10c is connected to the power distribution system 2 on the downstream side of the distribution substation 20 has been described with reference to FIG. In the embodiment, an isolated operation prevention system similar to that described in the first to fifth embodiments is provided in each of the plurality of distributed power supply systems, and the isolated operation prevention device in each of the plurality of distributed power supply systems is provided. The isolated operation prevention equipment in which the correction time determining means arbitrarily determines the correction time in each of the plurality of distributed power systems will be described below with reference to FIGS. 8 and 9.

  FIG. 8 is a schematic diagram of a power supply system in which distributed power systems A, B, and C are set downstream from the power transmission system 1 to which a power plant or the like is connected to the distribution substation 20. is there. The distribution substation 20 includes a transformer 21 for adjusting the voltage, and substation circuit breakers 22A, 22B, and 22C that are switches capable of stopping the supply of power to the distribution systems 2A, 2B, and 2C. It is prepared for. As shown in FIG. 8, consumers 10a, 10b, and 10c are connected to the distributed power system A, customers 10d, 10e, and 10f are connected to the distributed power system B, and the distributed power system C is connected to the distributed power system C. Consumers 10g, 10h, and 10i are connected. Since the configuration and operation of the isolated operation preventing device provided in these consumers 10a to 10i are the same as those of the isolated operation preventing device 14 provided in the customer 10a shown in FIG. In addition, system distribution impedances, transformers, and the like may exist in each of the distribution systems 22A, 22B, and 22C as in FIG. 1, but are not shown in FIG.

  As described above, the distributed power systems A, B, and C are provided on the downstream side of the distribution substation 20, and the respective distributed power systems are described in the first to fifth embodiments. Such an active signal is injected to prevent isolated operation. In the following, a mode in which the correction of the injection timing of the active signal similar to that in the first embodiment is performed in each of the distributed power systems A, B, and C will be described.

  FIG. 9 shows a waveform of an active signal output from the customer 10a to the customer 10i. In the isolated operation prevention devices of the customers 10a, 10b, and 10c provided in the distributed power supply system A, the active signal injection timing is corrected at the correction time t20 and provided in the distributed power supply system B. In the isolated operation preventing devices of the consumers 10d, 10e, and 10f, the injection timing of the active signal is corrected at the correction time t21, and each of the customers 10g, 10h, and 10i provided in the distributed power supply system C is corrected. In the operation preventing apparatus, the injection timing of the active signal is corrected at the correction time t22. In this way, the correction time preset in the correction time determination means 18 is the same for the same active system in the same distributed power system, and is different from the correction time of other distributed power systems. Set the time. For example, the correction time is the same in each of the distributed power systems A, B, and C, and the correction times are set to be different between the distributed power systems A, B, and C. The correction time in each distributed power supply system is also set in consideration of the operation status of the distributed power supply system, the connection status of the distributed power supply, the supply and demand status, and the like. As a result, power fluctuations such as reactive power and active power generated by injecting active signals between distributed power systems interfere with each other. The influence of power fluctuation by the isolated operation prevention device in a simple power system can be minimized.

  As described above, in the same manner as described in the first embodiment, in each of the distributed power systems A, B, and C, the injection of active signals in the individual operation prevention apparatus of each consumer at the same correction time. Since the timing is corrected, the power fluctuations do not interfere with each other, and the isolated operation is detected satisfactorily. As shown in the figure, between different distributed power systems, the correction time is made to be different from the correction times t20, t21, and t22 as shown in FIG. 9, thereby canceling the power fluctuation caused by the injection of the active signal. In addition, the influence of the power fluctuation caused by the active signal when the power system is normal can be minimized.

Schematic diagram of power supply system Active signal fluctuation pattern Processing flow of active signal injection timing correction according to the first embodiment Processing flow of active signal injection timing correction according to the second embodiment (A) is a voltage waveform of a distribution system, (b) is a fluctuation pattern of an active signal. (A) is a voltage waveform of a distribution system, (b) is a fluctuation pattern of an active signal. Processing flow of active signal injection timing correction according to the third embodiment Schematic diagram of power supply system Active signal fluctuation pattern

Explanation of symbols

1 Transmission system 2 Distribution system (Distributed power system)
10a to 10c Customer 11 Load device 12 Power generation device 13a to 13c Breaker 14 Isolated operation prevention device 15 Monitoring means 16 Time information obtaining means 17 Active signal generating / injecting means 18 Correction time determining means 20 Distribution substation 21 Transformer 22 Circuit breaker for substation 23a, 23b System impedance 24 Transformer

Claims (9)

An isolated operation preventing device provided corresponding to each of the distributed power sources in order to detect an isolated operation state of a distributed power system in which a plurality of distributed power sources are linked by an active method,
It used to detect the islanding state, a periodic active signal varying with time, generated based on a different periodic time information from the voltage waveform of the distributed power supply system, the active signal Active signal generating / injecting means for injecting into the output control unit of the distributed power source or injecting into the distributed power system, time information obtaining means for obtaining time information, and correction time of the active signal as the time information obtaining means Correction time determination means that can be determined based on the time information obtained in step (b), and monitoring means for monitoring the voltage waveform of the distributed power system,
The active signal generating / injecting means performs the initial correction of the injection timing of the active signal at the correction time determined by the correction time determining means, and then at the correction time determined by the correction time determining means. Alternatively, the isolated operation preventing apparatus is configured to repeat re- correction of the injection timing of the active signal based on the number of voltage cycles of the voltage waveform monitored by the monitoring means. An isolated operation preventing device provided corresponding to each of the distributed power sources in order to detect an isolated operation state of a distributed power system in which a plurality of distributed power sources are linked by an active method,
A periodic active signal, which is used to detect an isolated operation state and fluctuates with time, is generated based on periodic time information different from the voltage waveform of the distributed power system, and the active signal is generated. Active signal generating / injecting means for injecting into the output control unit of the distributed power source or injecting into the distributed power system, time information obtaining means for obtaining time information, and correction time of the active signal as the time information obtaining means Correction time determination means that can be determined based on the time information obtained in step (b), and monitoring means for monitoring the voltage waveform of the distributed power system,
In order for the active signal generating / injecting means to match the specific phase of the active signal with the specific phase of the voltage waveform monitored by the monitoring means immediately after the correction time determined by the correction time determining means, After performing the initial correction of the injection timing of the active signal, at the correction time determined by the correction time determination means or based on the number of voltage cycles of the voltage waveform monitored by the monitoring means An isolated operation preventing apparatus configured to repeat re-correction of the injection timing of the active signal .   The isolated operation prevention device according to claim 2, wherein the specific phase of the voltage waveform is a phase of a zero cross point or a phase of a peak point.   The isolated operation prevention device according to claim 2 or 3, wherein the specific phase of the active signal is a phase of a zero cross point, a peak point, a rising point, or a falling point.   The isolated operation prevention device according to any one of claims 1 to 4, wherein the time information acquisition unit receives the information about the standard time that is transmitted after being modulated by radio waves, and creates the time information.   The isolated operation prevention apparatus according to any one of claims 1 to 4, wherein the time information acquisition unit receives the information related to standard time transmitted via a communication network and creates the time information.   Provided with a plurality of isolated operation prevention devices provided corresponding to each of the distributed power supplies in order to detect the isolated operation state of the distributed power supply system in which a plurality of distributed power supplies are linked by an active method. An isolated operation prevention system,
  The isolated operation prevention system in which each of the plurality of isolated operation prevention devices includes the isolated operation prevention device according to any one of claims 1 to 6.   The isolated operation prevention system according to claim 7, wherein an internal time information type or external time input type isolated operation prevention device is linked to the distributed power supply system.   The isolated operation prevention system according to claim 7 or claim 8, wherein the isolated operation prevention system is provided for each of a plurality of distributed power systems,
  Independent operation prevention configured such that the correction time determination means of the isolated operation prevention device in each of the plurality of isolated operation prevention systems arbitrarily determines the correction time in each of the plurality of distributed power systems. Facility.

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