JP4227552B2 - Isolated operation prevention method and isolated operation prevention apparatus using the same - Google Patents

Description

  The present invention relates to a method and an isolated operation prevention device for preventing an independent operation of a power generation facility after a circuit breaker of a substation is opened in an electric power system in which the generation facilities are connected.

  Conventionally, in a power system where power generation facilities are connected, for example, when an accident such as a work outage or a ground fault occurs in the power system, the circuit breaker of the transmission substation of the power system is opened and connected to the power system. Power supply is stopped. However, the power generation facility may continue to operate without knowing that the circuit breaker is open under extremely special conditions, and may continue to supply power to the power system. Such operation of the power generation facility is referred to as isolated operation, and power is supplied to the power system that is recovering from the accident, resulting in danger such as electric shock to the accident recovery operator.

A method for preventing such a single operation of the power generation facility has conventionally existed, and basically the power generation facility is disconnected from the power system almost simultaneously with the opening of the circuit breaker of the substation. For example, the first method is to open the substation circuit breaker by contacting the power generation equipment via a dedicated signal line to stop the operation, or the second method is to open the substation circuit breaker. In addition, there is a method of detecting a transient voltage or frequency change caused by stopping power supply to the power system in which an accident has occurred and disconnecting the power generation equipment. In addition, as a third method, there is one disclosed in Patent Document 1, and when the circuit breaker of the substation is opened, one phase on the secondary side of the opened circuit breaker is grounded. The isolated operation is stopped based on the influence of the power generation equipment caused by the grounding.
JP-A-11-098696

  However, the first method has a cost problem in that it is expensive to install a dedicated signal line, and the signal line must be installed every time a new power generation facility is connected. In the second method, in the power system, when the power generation equipment and the load are in an equilibrium state, that is, when the production power (supply) of the power generation equipment and the power consumption (demand) of the load match, The effect of power transmission stoppage from the substation caused by being opened may not appear in the power system, and at this time, there is a problem of single operation detection accuracy that the single operation of the power generation facility cannot be stopped. The third method disclosed in Patent Document 1 has a risk of a risk that a short circuit may occur due to grounding.

  Accordingly, an object of the present invention is to provide an isolated operation prevention method and an isolated operation prevention device for a power generation facility that can detect isolated operation with high accuracy and safety at low cost.

According to the present invention for solving the above-described problems, a method for preventing a single operation of a power generation facility linked to a power system includes a step of constantly monitoring a power transmission state of the power generation facility, and a substation configured in the power system. A step of constantly checking whether the circuit breaker is open, a step of changing the load capacity of the load of the power system after confirming the opening of the circuit breaker, and a power transmission state of the power generation facility And a step of disconnecting or stopping the output of the power generation facility from the power system when the cycle changes with the specified period.

According to the present invention for solving the above problems, an isolated operation prevention device for preventing an isolated operation of a power generation facility linked to an electric power system includes a substation having a circuit breaker configured in the electric power system, and the interruption Monitoring the power transmission state of the power generation equipment, and a load application interrupting device for supplying a load to the power system on the secondary side of the generator or interrupting a load applied to the power system on the secondary side of the circuit breaker A power generation facility disconnecting device that disconnects the power generation facility from the power system based on the power transmission state of the power generation facility,
After opening the above circuit breaker,
The load input interruption device repeatedly performs the input and interruption of the load to and from the electric power system alternately for a predetermined time, and the power generation facility disconnection device performs the alternating predetermined time for each time. Based on the power transmission state of the power generation facility that has been repeatedly changed, the power generation facility is disconnected from the power system or stopped.

  The power generation facility disconnecting device disconnects the power generation facility from the power system or stops output based on a power transmission state of the power generation facility that has been repeatedly changed alternately for a predetermined time during a specified time. It is preferable to do this.

  It is preferable that the load charging / cutting-off device can perform the loading and blocking of the load on the system in a stepwise manner.

  The load preferably includes at least one of a resistor, a reactor or a capacitor.

  The change in the power transmission state of the power generation facility to be monitored is preferably at least one change in active power, reactive power, current, and voltage.

  According to the present invention, it is possible to provide an isolated operation prevention method and an isolated operation prevention device for a power generation facility that can detect isolated operation with high accuracy and safety at low cost. That is, the isolated operation prevention device according to the present invention can be configured with an inexpensive resistor, circuit breaker, detection device, and the like, so that it can be configured at a lower cost than the conventional method.

  In addition, since the power generation facility disconnection device detects the phenomenon caused by the load input circuit breaker that operates only after the system breaker is opened, it is possible to ensure reliable operation and to confirm that the phenomenon continues for a specified number of times. Therefore, it is possible to detect a single operation with high accuracy without malfunction.

  In addition, the load input circuit breaker operates for the first time after the system breaker is opened, and a resistance such as a general load can be used as the load. Is done.

  When many power generation facilities are connected to one system, the conventional method has been concerned about the influence on the system and the uncertainty of detection. However, according to the present invention, such a problem occurs. Absent.

  From the above, it can be said that the present invention is a method and apparatus having extremely excellent effects.

  Before describing embodiments of the present invention, the meaning of words and phrases used will be confirmed. “Connected” and “turn on” mean that they are electrically connected, and “disconnect”, “shut off”, and “open” mean that the electrical connection is broken. The phrase “primary side” refers to the power production site side (system power supply side) where high-voltage power is transmitted with reference to an arbitrary component of the power system and where there is a power plant such as hydropower or thermal power. On the other hand, the phrase “secondary side” refers to a power consumption area side (customer side) such as a general household or a factory where low-voltage power is transmitted.

  FIG. 1 is a schematic diagram of a power system 10 in which the isolated operation prevention device of the present invention is installed. The power system 10 is a substation 12 and a plurality of consumers (in the figure, three important homes 14, 16, 18) which are one of a plurality of systems (power system) supplied with power from the substation 12. ) Is connected to the system 20 connected.

  The substation 12 steps down the power transmitted from the primary side 22 and supplies it to a plurality of systems (secondary side), and cuts off the power supply between the transformer 24 and the plurality of systems. It has a circuit breaker (in the figure, a system 20 and a circuit breaker 26 for the system 20 are shown). Moreover, the substation 12 has the load injection | blocking interruption | blocking apparatus which comprises a part of isolated operation prevention apparatus of this invention in each of several systems (In the figure, the load injection | throwing interruption | blocking apparatus 28 for the system | strain 20 is shown. .) When the system circuit breaker is in an open state, the circuit breaker transmits a circuit breaker open signal notifying that it is in an open state to the load application circuit breaker (in the figure, the circuit breaker 26 for the system 20 is connected via a signal line, for example). The circuit breaker opening signal 30 is transmitted to the load application interrupting device 28).

  The system 20 will be described with reference to the system 20 among the plurality of systems. The load input interrupting device 28 includes a load 32 disposed so as to be able to perform disconnection and input to the secondary system 20 of the system circuit breaker 26, A load circuit breaker 34 for turning on or off 32 from the system 20, and a control unit 36 for controlling turning on or off of the load circuit breaker 34. In the present embodiment, the load 32 is always disconnected from the system 20 when the system circuit breaker 26 is turned on. When the control unit 36 receives the circuit breaker opening signal 30 from the system circuit breaker 26 and confirms that the system circuit breaker 26 has been opened, the control unit 36 loads the load 32 into the system 20 to interrupt the load. The device 34 is turned on. In addition, the control unit 36 implements turning on and off of the load 32 to the system 20 (opening and turning on the load breaker 34) based on an implementation index such as an execution duration set in the setting unit 38. To do.

  The plurality of consumers connected to the grid 20 has a load (in-consumer load) that consumes the power transmitted from the substation 12 (the consumer 18 in the figure has the in-customer load 40). Among the plurality of consumers, at least some of the consumers have power generation facilities (power generation devices) (the customer 18 in the figure has a power generation facility 42). In the customer 18, the customer load 40 and the power generation equipment 42 are connected to the system 20 at a branch point 44. The customer load 40 and the system 20 are connected between the customer load 40 and the branch point 44. The disconnector 46 for the load in the customer to cut off the connection, the breaker 48 for the power generation facility for disconnecting the power generation facility 42 from the system 20, and the common disconnection (disconnecting) from the system 20 simultaneously disconnecting the load 40 and the power generation facility 42. And 50.

  Further, the customer 18 monitors the energized state of the power line 52 between the power generation facility 42 and the power generation facility breaker 48, that is, the power transmission state of the power generation facility 42, and based on the monitoring result, the power generator breaker A power generation facility disconnecting device 54 that stops power transmission to the system 20 of the power generation facility 42 (disconnects the power generation facility 42 from the system 20) by opening 48 or stopping the output of the power generation facility 42 is provided. The power generation facility disconnecting device 54 constitutes a part of the isolated operation preventing device of the present invention.

  FIG. 2 shows a schematic configuration of the power generation facility disconnecting device 54. The power generation facility disconnecting device 54 of this embodiment monitors active power as indicating the power transmission state of the power generation facility 42. The power generation facility disconnecting device 54 detects a voltage V and a current I of the power line 50 from the transformer 56 and the current transformer 58 connected to the power line 50, and calculates a power. The disconnection determination unit 62 that determines the disconnection from the system 20 of the power generation equipment 42 based on the change in the active power calculated by the unit 60, the setting unit 64 that sets the determination criterion of the disconnection determination unit 62, and the disconnection determination unit In response to the determination that the power generation facility 42 is disconnected from the system 20, the signal that opens the circuit breaker 48 is output to the circuit breaker 48, or the signal that stops the power generation facility 42 is output to the power generation facility 42. A column signal output unit 66.

  Hereinafter, the isolated operation preventing operation performed by the isolated operation preventing apparatus of the present invention will be described. The described isolated operation prevention device detects an isolated operation of a power generation facility by a change in active power that appears when a load is configured by a resistor and the resistor is input to or disconnected from the system. Also, a plurality of values using alphabets (for example, P1) are used. In its use, values using lowercase alphabets are defined values (values that are not changed during operation in principle and set), and values using uppercase alphabets are measured values (calculated values).

  The load application blocking device 28 (control unit 36) according to the present invention operates according to the operation flow 100 shown in FIG. In step 110 of the flow 100, it is confirmed that the system breaker 26 is open. If the system breaker 26 is not open, step 110 is repeated.

  Next, when it is confirmed in step 110 that the system breaker 26 is opened, the load 32 is input to the system 20 via the load circuit breaker 34 in the next step 120.

  Subsequently, in step 130, it is confirmed that the time elapsed since the load 32 was input to the system 20 in step 120 and the specified time (input duration) t1 set in the setting unit 38 are confirmed. Step 130 is repeated until they match. In other words, the process of step 130 confirms whether the load 32 has been input to the system 20 for the specified input duration time t1. After the confirmation, in the next step 140, the load 32 input to the system 20 is disconnected from the system 20 via the load circuit breaker 34.

  In step 150, it is confirmed whether the time elapsed since the load 32 was disconnected from the system 20 in step 140 and the specified time (interruption duration) t2 set in the setting unit 38 are confirmed. Step 150 is repeated until they match. In other words, the processing in step 150 confirms whether the load 32 is disconnected from the system 20 for the specified interruption duration t2. After the confirmation, the process returns to step 110 again to confirm the opening of the system breaker 26.

  As shown in FIG. 5A, the operation of the load application interrupting device 28 that operates according to the operation flow 100 of FIG. 3 is represented along a time series. The load application interrupting device 28 applies the load 32 that is interrupted and maintained by the system 20 to the system 20 almost simultaneously with the release of the system circuit breaker 26, and thereafter, inputs the load 32 to the system 20. The interruption from the system 20 is repeatedly performed alternately at predetermined times (t1, t2), and the load 32 is disconnected from the system 20 and maintained almost simultaneously with the introduction of the system breaker 26.

  The charging continuation time t1 and the cutoff continuation time t2 may be different times or the same time.

  On the other hand, the power generation facility disconnecting device 54 (disconnection determining unit 62) according to the present invention is changed by the load 32 being turned on and off to the system 20 of the load turning-off device 28 before the system breaker 26 is opened. In order to determine the disconnection from the system 20 of the power generation equipment 42 from the change in the active power P output from the power generation equipment 42, which is different from the above, the operation is performed according to the flow described below.

  FIG. 4 is a disconnection determination flowchart of the power generation facility 42 implemented by the power generation facility disconnection device 42. The separation determination flow includes a main processing flow 200 and a plurality of sub processing flows (300, 400, 500, 600) hierarchized in several layers. Hereinafter, the description will be given according to the sequence determination flow.

  First, as shown in the main process flow 200 of FIG. 4, in step 210, the count C is reset to zero. The count C will be described later. Next, in step 220, a timing process is performed.

  The timing process in step 220 is performed according to the timing process flow 300 shown in FIG. In the time measurement process, first, at step 310, an increase determination process is performed.

  The increase determination process in step 310 is performed according to the increase determination process flow 400 shown in FIG. In the increase determination process, first, in step 410, a deviation calculation process is performed.

The deviation calculation processing in step 410 is performed according to the deviation calculation processing flow 600 shown in FIG. In the deviation calculation process, first, in step 610, the voltage V and the current I output from the power generation facility 42 are detected. Next, in step 620, the active power P is calculated from the voltage V and current I detected in step 610. Subsequently, in step 630, it calculates active power currently calculated value difference calculated by subtracting the previously calculated value from the P in step 620, the deviation P _V. Here, “previously calculated” means that it was calculated before time t3. Active power P is calculated each time the elapsed time t3, the deviation P _V shows the change of the effective power P during a time t3. Between time t3, when the active power P is increased, the deviation P _V is represented by a positive value, whereas, if you are reduced, the deviation P _V is expressed by a negative value. When the calculation of the deviation Pv ends in step 630, the deviation calculation process ends.

After deviation calculation processing in step 410 of increasing determination process ends, in step 420, it compares the active power p1 regulations and the deviation P _V of deviation calculation processing in step 410 is calculated. Active power p1 of this provision, the load 32 (resistance) is to be determined by the effective power (load supply active power) p _L and capacitance of the power generation facility 42 is consumed, consumed active power p _L is smaller than a positive value For example, it is represented by 0.1 × p _L. Therefore, the increase of the deviation P _V is the effective power p1 larger such active power P from paragraph may be inferred that there may have occurred after the input of the load 32 to the grid 20 by the load on and power-off device 28 . When the deviation P _V is the active power p1 is smaller than the prescribed again deviation calculation process returns to step 410 is performed, whereas, the deviation P _V is larger than active power p1 provisions, increase determination processing ends.

  After completion of the increase determination process in step 310 of the time measurement process, in step 320, measurement of time T1 is started. Next, a reduction determination process is performed in step 330. The time T1 will be described later.

The decrease determination process in step 330 is performed according to the decrease determination process flow 500 shown in FIG. In the decrease determination process, first, in step 510, the deviation calculation process is performed. After deviation calculation processing ends, in step 520, it compares the active power p2 defined the deviation P _V of deviation calculation processing in step 510 is calculated. Active power p2 of this provision, which is determined by the capacitance of the load consumption active power p _L and the power generation equipment 42, a negative value having a consumption active power p _L is smaller than the absolute value, e.g., -0.1 × p _L. Therefore, reduction of the effective power P as deviation P _V is smaller than the effective power p2 provisions, possibly load-on and power-off device 28 is caused by blocking the load 32 which has been introduced to the system 20 from the system 20 Can be guessed. When the deviation P _V is larger than the active power p2 defined, again deviation calculation process returns to step 510 is performed, whereas, the deviation P _V may enable provision power p2 is smaller than a decrease determination process is terminated.

  After completion of the decrease determination process in step 330 of the time measurement process, in step 340, the measurement of the time T1 started in step 320 is terminated. Next, in step 350, measurement of time T2 is started. Subsequently, in step 360, the above increase determination process is performed. After completion of the increase determination process in step 360, in step 370, the measurement of the time T2 started in step 350 is ended. The time T2 will be described later. When step 370 ends, the timing process ends.

After completion of the timing process in step 220, in step 230, it is determined whether the times T1 and T2 measured in the timing process coincide with the closing duration t1 and the cutoff duration t2. When determining the coincidence between the time T1 and the input duration t1, t1 ′, t1 ″ (for example, t1 ′ = 0.9 × t1) satisfying the relationship of t1 ′ <t1 <t1 ”in consideration of measurement errors and the like. , T1 ″ = 1.1 × t1) is set, and when the time T1 is within the range of t1 ′ to t1 ″, it is determined that it coincides with the charging duration t1. Similarly, when the time T2 is also set to t2 ′ and t2 ″ satisfying the relationship of t2 ′ <t2 <t2 ″ and is within the range of t2 ′ to t2 ″, it is determined that the time T2 coincides with the cutoff duration t2. .

t1 is if both the '<T1 <t1 "and t2'<T2<t2", the effective power P is, for the time t1, and maintained at least p1 increased state from an arbitrary value _{P 0,} the time t1 It means that after the lapse of time, the value returned to the value P ₀ before the increase and changed to maintain the approximate value P ₀ for the time t2. In addition, this change is caused when the load input interrupting device 28 outputs the load 32 (resistance) that consumes p _L of active power exceeding p1, and the power generation facility 42 outputs the active power P ₀ during the time t1. It can be inferred that the load 32 may be caused by being disconnected from the system 20 and maintained for the time t2 after the time t1. In step 230, when both t1 ′ <T1 <t1 ”and t2 ′ <T2 <t2” are satisfied, the process proceeds to the next step 240, and when both are not satisfied, the process returns to step 210.

Next, in step 240, the count C is added. Count C is the effective power P is, for the time t1, and maintained in at least p1 increased from an arbitrary value P _0, the time t1 after the elapse, the process returns to the value P ₀ before increasing during the time t2, the value When the state in which P ₀ is maintained is one cycle, the number of repetitions of the cycle is represented. Next, the routine proceeds to step 250.

  In step 250, the count C is compared with a defined count c. The prescribed count c is a number of at least 1 or more. This is because it is an early measure to determine that this change is caused by turning on and off the load 32 of the load making / breaking device 28 with a change in the active power P in one cycle. For example, this change is connected to the system 20. This is because it may be caused by a change in the load capacity of the load being loaded. Therefore, one cycle is repeated c times, in other words, with a change in the active power P during the period × c time, this change is caused by turning on and off the load 32 to the system 20 by the load turning-off device 28. Is determined. Thereby, erroneous determination can be prevented. If the count C does not exceed c, the process returns to step 230. If the count C exceeds c, the process proceeds to the next step 260.

  In step 260, in order to disconnect the power generation facility 42 from the grid 20, a disconnection signal for opening the power generation facility breaker 48 or stopping the operation of the power generation facility 42 is sent to the power generation breaker 48 or the power generation facility 42. Output. As a result, the power generation facility 42 is disconnected from the system 20, and the single operation of the power generation facility 42 is prevented.

  According to the above flow, it was determined that the change in the active power output from the power generation facility 42 was due to the load 32 being turned on and off by the load input / cutoff device 28. Obviously, the present invention is not limited to this flow.

Here, in FIG. 5, a change in active power P from the power generation equipment 42 used in the disconnection determination, and a corresponding change in the deviation P _V, expressed in chronological order. For reference, FIG. 5 (a) shows, in chronological order, the loading of the load 32 to the system 20 and the interruption from the system 20 that are repeatedly performed alternately at predetermined times (t1, t2). (It shows the time-series state of load.) FIG. 5B shows a time series change of the active power P output from the power generation facility 42 corresponding to the time series state of the load 32 shown in FIG. FIG. 5 (c) shows a time-series change in P _V corresponding to the effective power P shown in Figure 5 (b).

Active power P shown in FIG. 5 (b), when the load 32 is turned on, determined the load 32 from the capacitance of the _{p L} and power generation equipment 42 consumed by the load 32 from the previous _{P 0} to be introduced to the system 20 _{p G} Only increases to P ₀ + p _G. The load 32 is cut off from the system 20 after the time t1 after increasing to the active power P ₀ + p _G , so that the active power P ₀ decreases. After P ₀ and decreases to time t2, by the load 32 is turned on again, the effective power P is increased again as _P 0 + _{p G,} thereafter, active power, to decrease the _P 0 + _{p G} to _{P 0} Repeat the increase.

Deviation _{P V,} as shown in FIG. 5 (c), are calculated for each time t3 (calculated interval time), when the effective power P is increased from _{P 0} to _P 0 + _{p G,} positive beyond p1 (+) to increase from 0 only _{p G.} On the other hand, when the active power P decreases from P ₀ + p _G to P _0, it exceeds p 2 and decreases negatively (−) from 0 to p _G. It is 0 when there is no change in the active power P. P _V is time T1 time until have been described above when negatively decreased beyond p2 from the time of increase beyond positive p1, positively p1 from when negatively decreased beyond p2 The time until the time of increase exceeds time is time T2. In FIG.5 (c), time T1 is substantially corresponded with injection | throwing-in continuous time t1, and time T2 is substantially corresponded with interruption | blocking continuation time t2.

Further, as apparent from FIG. 5, the relationship between the turn-on continuation time t1, the cutoff continuation time t2, and the calculation interval time t3 is such that t3 is shorter than t1 and t2 in order to reliably detect a change in the active power P. Must. In addition, before the system breaker 26 is opened, if the active power P ₀ output from the power generation facility 42 fluctuates at an arbitrary cycle, the charging duration t1 and the interruption are cut off so as not to be the same as the arbitrary cycle. It is preferable to set the duration t2 to a sufficiently short time, for example, 20 to 200 milliseconds.

Further, the effective power p1, p2 paragraph, if the transmission state of the power system breaker 26 open before the power plant 42 is stable, i.e. when the variation of P ₀ is small, the absolute value of p1, p2 0 By bringing them closer, it is possible to improve the accuracy of detecting a change in active power due to the load 32 being turned on and off. On the other hand, when the power transmission state is not stable, that is, when the fluctuation of P ₀ is large, the prescribed active power p 1 is set so as not to mistake the fluctuation of P ₀ due to the load 32 being turned on and off. , the absolute value of p2, may be set so as to approach the determined p _G from the power consumption p _L and capacitance of the power generation equipment 42 of the load.

Thus, numerical values represented by the small letters, poured duration t1, blocking duration t2, calculated time interval t3, active power p1, p2 defined, load supply active power p _L is the power generation facility 42 interconnection The number of important houses, the total amount of loads, the number of power generation facilities, etc. that the system 20 has can be set appropriately.

  By the way, in the above embodiment, the disconnection from the system of the power generation facility is determined based on the change in the active power output from the power generation facility, but the change in the transmission state other than the active power, for example, reactive power, current It is also possible to determine the disconnection of the power generation equipment based on the change in voltage. It is also possible to determine the disconnection of the power generation equipment based on a plurality of changes among active power, reactive power, current, and voltage.

  Moreover, although resistance was used as load in said embodiment, it can implement also with another load, for example, a reactor, a capacitor, and it is also possible to comprise a load combining these.

  Furthermore, in the above-described embodiment, the load is input (shut off) to the system at one time. However, the load may be implemented step by step. For example, 50% of the total load capacity of the load is first input, and then the remaining 50% is input, so that the load capacity of the input load is changed in stages. It is also possible to disconnect the power generation equipment from the grid based on the power transmission state of

  In addition, when the load input to the system is composed of, for example, a resistor, a reactor, and a capacitor, it is possible to sequentially input these. For example, after the circuit breaker is opened, the resistor, the reactor, and the capacitor are inserted into the system in this order (disconnected from the system), and in the power transmission state of the power generation equipment, changes due to the input of resistance, changes due to the reactor, and changes due to the capacitor are confirmed It is also possible to disconnect the power generation facility from the grid.

  Of course, in the above-described embodiment, after the system breaker is opened, the power generation facility is disconnected from the system based on the change in the power transmission state of the power generation facility caused by loading the load interrupted from the system into the system. However, on the contrary, it is also possible to disconnect the power generation facility based on the change in the power transmission state of the power generation facility caused by cutting off the load applied to the system from the system.

It is the schematic of the electric power grid | system where the islanding prevention apparatus which concerns on this invention is used. It is the schematic of the power generation equipment disconnection apparatus which comprises a part of isolated operation prevention apparatus which concerns on this invention. It is an operation | movement flow of the load addition interruption | blocking apparatus which comprises a part of isolated operation prevention apparatus which concerns on this invention. It is a processing flow for determining and executing the disconnection of the power generation facility of the power generation facility disconnection device. It is a time-sequential diagram of the change of the active electric power from a power generation facility which arises by injection | throwing in and interruption | blocking of the load to a system | strain, and the change of the deviation corresponding to it.

Explanation of symbols

10 power system, 12 substation, 14 customer, 16 customer, 18 customer, 20 system, 22 primary side, 24 transformer, 26 system circuit breaker, 28 load input circuit breaker, 30 circuit breaker open signal, 32 Load, 34 Load circuit breaker, 36 Control unit, 38 Setting unit, 40 Load, 42 Power generation facility, 44 Branch point, 46 Circuit breaker, 48 Circuit breaker, 50 Circuit breaker, 52 Power line, 54 Power generation facility disconnection device, 56 Voltmeter, 58 Ammeter, 60 Power calculation unit, 62 Disconnection determination unit, 64 Setting unit, 66 Disconnection signal output unit,
P active power, V voltage, I current, T1 measurement time, T2 measurement time, C count,
t1 input duration, t2 cutoff duration, t3 calculation interval time, p _L load active power consumption, p _G power generation facility active power variation, p1 prescribed active power, p2 prescribed active power, c prescribed count

Claims (6)

A method for preventing isolated operation of a power generation facility connected to an electric power system,
A step of constantly monitoring the power transmission state of the power generation facility;
A step of constantly confirming the opening of the circuit breaker of the substation included in the power system;
After confirming the opening of the circuit breaker, the step of changing the load capacity of the load of the power system at a specified period ;
And a step of disconnecting or stopping the output of the power generation facility from the power system when the power transmission state of the power generation facility changes at the specified cycle .   In the isolated operation prevention device that prevents the isolated operation of the power generation facility linked to the power system,
  A substation including a circuit breaker included in the power system;
  A load application interrupting device for supplying a load to the power system on the secondary side of the circuit breaker or interrupting a load applied to the power system on the secondary side of the circuit breaker;
  A power generation facility disconnecting device that monitors the power transmission state of the power generation facility and disconnects the power generation facility from the power system based on the power transmission state of the power generation facility;
  After opening the above circuit breaker,
  The load input interruption device repeatedly performs the input and interruption of the load to the electric power system alternately for each predetermined time,
  The power generation facility disconnecting device is configured to disconnect or stop the output of the power generation facility from the power system based on a power transmission state of the power generation facility that has repeatedly changed alternately at predetermined times. Isolated operation prevention device.   The power generation facility disconnecting device disconnects the power generation facility from the power system or stops output based on the power transmission state of the power generation facility that has been repeatedly changed alternately for a predetermined time during a specified time. The isolated operation prevention device according to claim 2, wherein:   The isolated operation prevention device according to claim 2 or 3, wherein the load input interruption device implements the introduction and interruption of the load to the system in a stepwise manner.   The islanding operation prevention device according to any one of claims 2 to 4, wherein the load includes at least one of a resistor, a reactor, or a capacitor.   The isolated operation prevention according to any one of claims 2 to 5, wherein the change in the power transmission state of the power generation facility to be monitored is at least one change in active power, reactive power, current, and voltage. apparatus.

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