JP5986827B2 - Power system stabilization analysis device, power system stabilization analysis method, and power system stabilization analysis program - Google Patents

Description

  The present invention relates to a power system stabilization analysis device, a power system stabilization analysis method, and a power system stabilization analysis program.

  In an electric power system that supplies electric power from a power generation device, a failure such as a short circuit or a ground fault due to a lightning strike, or a load fluctuation due to an increase or decrease in power consumption can be considered. As described above, when an external factor such as a failure or a load change occurs during operation of the power generation apparatus, a phenomenon of power fluctuation that causes a voltage or the like to oscillate in the power system may occur. Furthermore, due to power fluctuations, the rotation speed between generators cannot be synchronized, and there is a risk that it may be difficult to maintain the operation of the entire system. Therefore, there is a case where the generator is separated from the power system to recover the synchronization. When external factors such as failure and load fluctuation occur, the degree to which the rotation of the generator is synchronized again and a stable operating state is recovered without causing the generator to drop off or the system separation is called synchronization stability. Among them, the synchronization stability when caused by a large disturbance such as a failure is called transient stability, and the synchronization stability when caused by a minute disturbance such as a load fluctuation is called a steady state stability.

  For example, conventionally, immediately after the occurrence of an accident, the generator and load are disconnected from the power system, and at the same time, by opening and closing a power capacitor installed in a substation or the like in the power system or a phase adjuster such as a shunt reactor. A power system stabilizing device that stabilizes the power system is known.

  In addition, when the use of electricity changes and the power demand in the power system changes suddenly or when the generator is dropped, there is a possibility that the voltage cannot be maintained in the power system. The ability to maintain a stable voltage in the power system even when demand changes suddenly is called voltage stability.

  For example, a conventional technique is known in which when a voltage drops in an electric power system, a load is cut off to maintain voltage stability.

  In this regard, conventional power generators such as thermal power generation have a high ability to maintain electric power, so that the operation can be continued stably unless the voltage change is so large. For these reasons, in a power system using a conventional generator, voltage stability is a problem when the load fluctuates when the distance between the generator and the load is long. Therefore, in the case where a fault such as a ground fault or a short circuit occurs in the conventional power system, the maintenance of the transient stability should be mainly considered, and the voltage stability has not become a problem so much.

  In recent years, the reduction of carbon dioxide emissions, which is thought to cause global warming, has become a major issue in modern society. As a means of reducing carbon dioxide emissions, the introduction of power generation systems using renewable energy such as wind power generation and solar power generation has become popular.

  When a power generation system using renewable energy is introduced, a conventional generator such as thermal power generation is removed from the power generation system in order to keep the amount of supplied power equal to the load. Power generation systems that use renewable energy, especially solar power generation, have a weak ability to support voltage. Therefore, when the power generation system using renewable energy and the conventional generator are replaced, the ability to support the voltage of the power system is reduced.

  Therefore, in a power system that introduces a power generation system that uses renewable energy, it is preferable to consider not only maintaining transient stability but also maintaining voltage stability when a failure occurs.

JP 2011-097705 A

  However, in the electric power system using the conventional generator, as described above, the transient stability and the voltage stability have been considered in different scenes. Therefore, it is difficult to associate and consider the transient stability and the voltage stability at the time of occurrence of power fluctuation due to a failure or the like in either the conventional technique for maintaining the excessive stability or the conventional technique for maintaining the voltage stability. In other words, in a power system where renewable energy is introduced, in a situation where the problems of transient stability and voltage stability occur in association with each other, it is difficult for the conventional technology to maintain stable operation of the power system. It was.

  The disclosed technology has been made in view of the above, and includes a power system stabilization analysis apparatus, a power system stabilization analysis method, and a power system stabilization that presents control for maintaining both transient stability and voltage stability. The purpose is to provide an analysis program.

In one aspect, the power system stabilization analysis apparatus, the power system stabilization analysis method, and the power system stabilization analysis program disclosed in the present application are configured so that the transient stability analysis unit Based on the data, a power supply limit for maintaining the transient stability when the contingency failure occurs is determined. The voltage stability analysis unit maintains the voltage stability when the assumed failure occurs based on the power state and the assumed failure data when the power supply restriction determined by the transient stability analysis unit is performed. Determining one or both of the power limit and the load limit.

  According to one aspect of the power system stabilization analysis device, the power system stabilization analysis method, and the power system stabilization analysis program disclosed in the present application, it is possible to present a control that maintains both transient stability and voltage stability. There is an effect that can be done.

FIG. 1 is a block diagram of a power system stabilization analysis apparatus according to an embodiment. FIG. 2 is a conceptual diagram of a power system model to be analyzed by the power system stabilization analysis apparatus according to the present embodiment. FIG. 3 is a diagram illustrating a time region in which an influence due to synchronization stability and voltage stability occurs. FIG. 4 is a diagram illustrating an example of a power system model to be analyzed by the power system stabilization analysis apparatus according to the embodiment. FIG. 5 is a diagram showing the change over time in the internal phase difference angle of the generator under investigation of excessive stability. FIG. 6 is a diagram illustrating the voltage output from the generator 101 that is the target for maintaining the excessive stability and the effective output thereof. FIG. 7 is a diagram illustrating the transition of the PV curve. FIG. 8A is a diagram illustrating the voltage output from the generator 102 that is the target of voltage stability maintenance control and the effective output thereof. FIG. 8B is a diagram illustrating the effective load and its invalid load at the load node 105 that is the target of voltage stability maintenance control. FIG. 9 is a diagram illustrating an operation state of the voltage control device and a change in voltage. FIG. 10 is a diagram illustrating a change with time of the internal phase difference angle of the generator after the voltage stability control. FIG. 11 is a diagram illustrating a PV curve at the load node 103 after the operation of the voltage control apparatus. FIG. 12 is a flowchart of analysis processing performed by the power system stabilization analysis apparatus according to the embodiment.

  Embodiments of a power system stabilization analysis device, a power system stabilization analysis method, and a power system stabilization analysis program disclosed in the present application will be described below in detail with reference to the drawings. The power system stabilization analysis apparatus, power system stabilization analysis method, and power system stabilization analysis program disclosed in the present application are not limited to the following embodiments.

  FIG. 1 is a block diagram of a power system stabilization analysis apparatus according to an embodiment. FIG. 2 is a conceptual diagram of a power system model to be analyzed by the power system stabilization analysis apparatus according to the present embodiment.

  As shown in FIG. 2, for example, the power system to be analyzed includes a plurality of generators 11 to 13 and 21 to 23, load nodes 41 and 42, and voltage control devices 51 and 52. The generators 11 to 13 and the generators 21 to 23 are connected by a plurality of power transmission lines 31 and 32. The load nodes 41 and 42, the voltage control devices 51 and 52, and the power transmission lines 31 and 32 are connected by a node 34. Electricity generated by the generators 11 to 13 and 21 to 23 flows through the power transmission lines 31 and 32. Then, the electric power output from the generators 11 to 13 and 21 to 23 is transformed at the substation and supplied to the load nodes 41 and 42. The load nodes 41 and 42 are aggregates of things that use power such as homes and factories. Hereinafter, the amount of electricity used in the load nodes 41 and 42 is referred to as “load”. The voltage control devices 51 and 52 are arranged at a substation or the like.

  FIG. 3 is a diagram illustrating a time region in which the influence of the synchronization stability and the voltage stability occurs. The horizontal axis in FIG. 3 represents the passage of time. FIG. 3 shows a case where a failure occurs at time 200. In the actual power system, when a failure occurs at the time point 200, an influence on the synchronization stability occurs immediately after that in the period represented by the synchronization stability region 201. Here, the synchronization stability includes transient stability that represents the stability of power fluctuation due to a large disturbance such as a failure, and steady-state stability that represents the stability of power fluctuation due to a small disturbance such as a load change at the load node. Degrees included. The voltage stability is affected from the vicinity of the end of the synchronization stability region 201 to the period represented by the voltage stability region 202. Further, in the voltage control device operation region 203 during the influence on the voltage stability, the voltage control device operation for adjusting the voltage of each load node operates. As described above, when a failure occurs in the power system, after the influence on the synchronization stability occurs, the influence on the voltage stability occurs.

  Therefore, the power system stabilization analysis apparatus according to the present embodiment performs a study for maintaining the excessive stability in the synchronization stability according to the order of the occurrence of the influence, and then a study for maintaining the voltage stability. Do. Furthermore, the power system stabilization analysis apparatus according to the present embodiment examines the steady state stability when the voltage control apparatus operates in a state after ensuring the maintenance of the voltage stability.

  As shown in FIG. 1, the power system stabilization analysis apparatus according to this embodiment includes an input unit 1, a transient stability analysis unit 2, a voltage stability analysis unit 3, a voltage control device operation confirmation unit 4, and a steady state stability. A confirmation unit 5 and a control information notification unit 6 are included.

  The operator uses the input unit 1 to input conditions for a failure that is assumed to occur in the power system to be analyzed (hereinafter referred to as “supposed failure”). The input unit 1 transmits the condition of the assumed failure input by the operator to the transient stability analysis unit 2. Here, the assumed failure is a failure in which a failure has occurred in the accident location 33 because a lightning strike has occurred in the transmission line 32 and a ground fault or a short circuit has occurred. Then, the operator inputs a state in which the connection between both ends of the power transmission line 32 including the accident location 33 is disconnected because no contingency has occurred and no electricity flows through the power transmission line 32 as a condition for the contingency failure.

  The transient stability analysis unit 2 preliminarily determines the normal voltage, valid output, invalid output, valid load, invalid load, and operating state of the voltage control device of the generators 11 to 13 and 21 to 23 in the power system to be analyzed. I remember it.

  The transient stability analysis unit 2 receives an input of a contingency failure condition from the input unit 1. And the excessive stability analysis part 2 calculates | requires the time-dependent change of the internal phase difference angle of each generator when an assumption failure generate | occur | produces. For example, in the power system as shown in FIG. 2, the rotation speeds of the generators 11 to 13 and the rotation speeds of the generators 21 to 23 coincide with each other in a normal state. On the other hand, when an assumed failure occurs and the connection at both ends of the transmission line 32 is released, the rotational speeds of the generators 11 to 13 and the generators 21 to 23 may be different. The excessive stability analysis unit 2 determines that the excessive stability cannot be maintained when the difference in rotational speed between the generators 11 to 13 and the generators 21 to 23 becomes large and diverges. Here, since an assumed failure is assumed in which the excessive stability cannot be maintained, the excessive stability analysis unit 2 diverges the internal phase difference angle of each generator due to a change over time when the assumed failure occurs. Confirm.

  Next, the transient stability analysis unit 2 sets the generator to be disconnected from the power system so that the power fluctuation is converged by reducing the difference in rotational speed between the generators 11 to 13 and the generators 21 to 23. Select from 11-13 and generators 21-23. Hereinafter, disconnecting the generator from the power system is referred to as “power limit”. In addition, an amount indicating how many generators are disconnected from the power system is referred to as a “power limit”.

  The excessive stability analysis unit 2 determines whether or not the internal phase difference angle of the generator converges due to the change with time due to the power supply restriction, and the power fluctuation in the power system converges. The excessive stability analysis unit 2 increases the power limit amount when the power fluctuation does not converge. In this way, the transient stability analysis unit 2 obtains the power limit amount at which the power fluctuation converges while gradually increasing the power limit amount. Thereby, the excessive stability analysis part 2 determines the generator used as the object of the power supply restriction | limiting for converging a power fluctuation. Hereinafter, the control for converging the power fluctuation and maintaining the excessive stability is referred to as “excessive stability maintaining control”.

  Here, the case where the generator 11 is selected as the generator to be disconnected from the power system by the transient stability analysis unit 2 will be described. The transient stability analysis unit 2 obtains the voltages at the generators 11 to 13 and 21 to 23 and the load nodes 41 and 42, the effective output, the invalid output, the effective load, the invalid load, and the operation state of the voltage control device. In this case, since the generator 11 is disconnected from the power system, the voltage and effective output of the generator 11 become 0, and as a result, the effective output and invalid output of the power system decrease. Further, the generators 12, 13 and 21 to 23, and the voltages and effective outputs at the load nodes 41 and 42 are changed due to the generator 11 being disconnected.

  The transient stability analysis unit 2 uses the voltages at the generators 11 to 13 and 21 to 23 and the load nodes 41 and 42, the valid output, the invalid output, the valid load, the invalid load, and the operation state values of the voltage control device. Then, the change with time of the internal phase difference angle of the generator in a state where the restriction for maintaining the excessive stability is performed is obtained. For example, by disconnecting the generator 11 from the power system, the internal phase difference angle deviation of the generator becomes smaller, and the power fluctuation converges. Therefore, the transient stability analysis unit 2 determines to disconnect the generator 11 from the power system as the transient stability maintenance control as a power source limitation for maintaining the transient stability against the assumed failure.

  The transient stability analysis unit 2 includes the generators 11 to 13 and 21 to 23, and the voltage, valid output, invalid output, valid load, invalid load and the load nodes 41 and 42 when the transient stability maintenance control is performed. Obtain the value of the operating state of the voltage controller. Then, the transient stability analysis unit 2 determines the operating states of the obtained generators 11 to 13 and 21 to 23, and the voltages, effective outputs, invalid outputs, valid loads, invalid loads, and voltage control devices at the load nodes 41 and 42. The voltage analysis data including is generated. Then, the transient stability analysis unit 2 outputs the voltage analysis data to the voltage stability analysis unit 3.

  When the internal phase difference angle diverges, the transient stability analysis unit 2 limits the power until the transient stability can be maintained, that is, until the internal phase difference angles of the generators 11 to 13 and 21 to 23 converge. Increase the amount. And the excessive stability analysis part 2 produces | generates voltage analysis data from the control information of the state (state where electric power fluctuation converged) in which the excessive stability became maintainable. Then, the transient stability analysis unit 2 outputs the voltage analysis data to the voltage stability analysis unit 3.

  In addition, the transient stability analysis unit 2 is after voltage stability maintenance control to which voltage stability maintenance control (hereinafter referred to as “voltage stability maintenance control”) by the voltage stability analysis unit 3 to be described later is added. Is obtained from the voltage stability analysis unit 3. The control information after the voltage stability maintenance control is added includes the power restriction information added by the voltage stability analysis unit 3 in addition to the control information output from the transient stability analysis unit 2 to the voltage stability analysis unit 3. Etc. are included. The load limitation indicates that the load is disconnected from the power system. And the excessive stability analysis part 2 acquires the time-dependent change of the internal phase difference angle of each generator in the state which performed power supply restriction | limiting, load restriction | limiting, etc. according to the received control information after voltage stability maintenance control. When the internal phase difference angle diverges, the transient stability analysis unit 2 notifies the voltage stability analysis unit 3 of the change of the voltage stability maintenance control.

  On the other hand, when the internal phase difference angle converges, the transient stability analysis unit 2 outputs a notification that the transient stability can be maintained to the voltage stability analysis unit 3.

  The voltage stability analysis unit 3 receives input of voltage analysis data from the transient stability analysis unit 2. And the voltage stability analysis part 3 can maintain voltage stability in each load node, when the control by the power supply limitation determined by the excessive stability analysis part 2 is performed using the received voltage analysis data. It is determined whether or not. At this time, in order to add a condition that the voltage control device does not operate, the voltage stability analysis unit 3 determines whether or not to maintain the voltage stability at each load node after locking the operation of the voltage control device.

  The voltage stability analysis unit 3 has a case where the operating points of the PV curves at all load nodes are in the region of increasing the voltage and the difference between the load at the stability limit of the PV curve and the load at the operating point is equal to or greater than the determination threshold. In addition, it is determined that the voltage stability is maintained. The PV curve is a graph showing the load amount at the load node on the horizontal axis and the voltage at the load node on the vertical axis. The PV curve operating point is an intersection of the load characteristic and the PV curve, and represents that the voltage and load in the power system are in an equilibrium state. The stability limit of the PV curve is expressed as the apex of the PV curve and represents the upper limit of the load at the load node. Here, it is preferable that the determination threshold is determined by the required stability. The determination threshold is small when the required stability is low, and is large when the required stability is high.

  The voltage stability analysis unit 3 is in a state where the voltage stability cannot be maintained even if there is one load node in which the voltage stability cannot be maintained in the state in which the voltage stability stability control is determined by the voltage stability analysis unit 2. Power supply restrictions and load restrictions are added so that can be maintained. Then, the voltage stability analysis unit 3 outputs control information when the voltage stability maintenance control is performed to the transient stability analysis unit 2.

  When the control information when the voltage stability maintenance control is performed is notified from the transient stability analysis unit 2 that the transient stability can be maintained, the voltage stability analysis unit 3 performs the voltage stability maintenance control. In this case, the voltages at the generators 11 to 13 and 21 to 23 and the load nodes 41 and 42, the valid output, the invalid output, the valid load, the invalid load, and the values of the operation states of the voltage control device are obtained. Then, the voltage stability analysis unit 3 determines the generators 11 to 13 and 21 to 23 and the voltage, effective output, invalid output, valid load, invalid load, and operating state of the voltage control device at the load nodes 41 and 42. Create operation check data including. Then, the voltage stability analysis unit 3 outputs the created operation confirmation data to the voltage control device operation confirmation unit 4.

  On the other hand, when the voltage stability analysis unit 3 receives a change notification of the voltage stability maintenance control from the transient stability analysis unit 2 with respect to the control information when the voltage stability maintenance control is performed, the voltage stability analysis unit 3 again Review voltage stability.

  If the voltage stability analysis unit 3 is able to maintain the voltage stability at all load nodes without adding power source limitation or load limitation to the excessive stability maintenance control determined by the transient stability analysis unit 2, Operation confirmation data is created from the voltage analysis data received from the stability analysis unit 2. Then, the voltage stability analysis unit 3 outputs the created operation confirmation data to the voltage control device operation confirmation unit 4. In this case, the generator 11 to 13 and 21 to 23 included in the operation confirmation data, and the voltage at the load nodes 41 and 42, the valid output, the invalid output, the valid load, the invalid load, and the value of the operation state of the voltage control device are It is the same as that of voltage analysis data. Therefore, in this case, the voltage stability analysis unit 3 may use the voltage analysis data as operation confirmation data.

  The voltage control device operation confirmation unit 4 receives operation confirmation data from the voltage stability analysis unit 3. And the voltage control apparatus operation | movement confirmation part 4 confirms the voltage change in the electric power system of the state which maintained both the excessive stability and voltage stability using operation | movement data. If there is a voltage constraint violation node, the voltage control device operation confirmation unit 4 adds control by the voltage control device in the power system to eliminate the voltage constraint violation. Here, the voltage constraint violation indicates a case where the voltage of the node is equal to or higher than a threshold value determined in advance from the reference voltage. For example, when the reference voltage at the node 34 in FIG. 2 is 500,000 V and the threshold is ± 5%, the voltage control device operation confirmation unit is not selected if the voltage at the node 34 does not fall within 500,000 V ± 5% 4 determines that there is a voltage constraint violation node. In that case, the voltage control device operation confirmation unit 4 operates the voltage control device corresponding to the node 34 which is a voltage constraint violation node, and controls the bus voltage to be within 500,000 V ± 5%.

  If there is no voltage constraint violation node in the voltage change confirmed using the operation check data, the voltage control device operation confirmation unit 4 includes the generators 11 to 13 and 21 to 23 in the state where there is no voltage constraint violation node, and the load node. The voltages at 41 and 42, valid output, invalid output, valid load, invalid load, and values of the operation state of the voltage control device are obtained. Then, the voltage control device operation confirmation unit 4 operates the generators 11 to 13 and 21 to 23 and the voltage, effective output, invalid output, valid load, invalid load, and voltage control device at the load nodes 41 and 42. Create steady state stability confirmation data including state. Then, the voltage controller operation confirmation unit 4 outputs the created steady state stability confirmation data to the steady state stability confirmation unit 5. Further, when there is no operation of the voltage control device, the generators 11 to 13 and 21 to 23 included in the steady state stability confirmation data, and the voltages at the load nodes 41 and 42, the effective output, the invalid output, the effective load, The values of the operation state of the invalid load and the voltage control device are the same as those of the operation confirmation data. Therefore, in this case, the voltage control device operation confirmation unit 4 may use the operation confirmation data as the steady state stability confirmation data.

  The steady state stability confirmation unit 5 receives the steady state stability confirmation data from the voltage controller operation confirmation unit 4. The steady-state stability confirmation unit 5 uses the received steady-state stability confirmation data to perform control applied by the transient stability analysis unit 2, the voltage stability analysis unit 3, and the voltage controller operation confirmation unit 4. If so, it is determined whether the steady state stability can be maintained at each load node. Specifically, the steady-state stability confirmation unit 5 performs maintenance of the transient stability and voltage stability, and changes in load after a while has passed since the control by the voltage control device is performed. The steady state stability due to micro disturbance is examined.

  When it is determined that the steady state stability can be maintained, the steady state stability confirmation unit 5 notifies the control information of the power limit, the load limit, and the operation of the voltage control device in the state where it is determined that the steady state stability can be maintained. Output to unit 6.

  On the other hand, when it is determined that the steady state stability cannot be maintained, the steady state stability confirmation unit 5 performs the voltage control device operation confirmation unit 4 in addition to the voltage stability control information and the voltage stability maintenance control information. The lock control of the operated voltage control device and the generation information of the voltage constraint violation node are output to the control information notification unit 6.

  The control information notification unit 6 receives from the steady state stability confirmation unit 5 input of information on power supply limitation, load limitation, and operation of the voltage control device. Then, the control information notifying unit 6 notifies the operator of the stabilization control information by outputting the received power limit, load limit and voltage control device operation information to an output device such as a monitor.

  Next, taking the power system model of FIG. 4 as an example, the stabilization analysis by the power system stabilization analysis apparatus according to the present embodiment will be described more specifically. FIG. 4 is a diagram illustrating an example of a power system model to be analyzed by the power system stabilization analysis apparatus according to the embodiment. Specifically, the power system model of FIG. 4 is a model obtained by partially correcting the daytime cross section of the Institute of Electrical Engineers West 30 machine system model.

  In FIG. 4, a target to which a symbol with a number added to G is assigned represents a generator. Further, in FIG. 4, objects to which only numbers are assigned represent loads, transmission lines, and transformers.

  The transient stability analysis unit 2 stores the power system model of FIG. And the excessive stability analysis part 2 calculates | requires the time-dependent change of the internal phase difference angle of each generator when the input assumption fault generate | occur | produces in the power system model of FIG. Here, a case where a short circuit or a ground fault due to a lightning strike or the like occurs at point 100 as an assumed failure will be described.

  The transient stability analysis unit 2 acquires the graph 301 in FIG. 5 as a change over time of the internal phase difference angle of each generator when an assumed failure occurs. FIG. 5 is a diagram showing the change over time in the internal phase difference angle of the generator under investigation of excessive stability. In FIG. 5, the vertical axis represents the internal phase difference angle, and the horizontal axis represents the passage of time. As shown in the graph 301, it can be seen that the internal phase difference angle diverges before the excessive stability maintenance control is performed. That is, when the assumed failure occurs, the excessive stability analysis unit 2 determines that the excessive stability cannot be maintained. Therefore, the excessive stability analysis unit 2 performs power source limitation and maintains the excessive stability. For example, the transient stability analysis unit 2 performs power source limitation (hereinafter referred to as power source limitation of the generator 101) that disconnects the generator 101 from the power system.

  Furthermore, the transient stability analysis unit 2 obtains the voltage, the effective output, the invalid output, the effective load, the invalid load, and the operation state of the voltage control device in the power system generator and the load node when the power supply is limited. . Then, the transient stability analysis unit 2 maintains the transient stability by using the obtained voltages, valid output, invalid output, valid load, invalid load, and operating state values of the voltage control device at the other generators and load nodes. The change with time of the internal phase difference angle of the generator after control is acquired. In the present embodiment, the transient stability analysis unit 2 acquires the graph 302 of FIG. 5 as the change over time of the internal phase difference angle of the generator after the generator 101 is stopped. It can be seen from the graph 302 that the internal phase difference angle has converged and the power fluctuations have converged to maintain the excessive stability. That is, the excessive stability analysis unit 2 determines that the excessive stability can be maintained by disconnecting the generator 101 from the power system.

  The transient stability analysis unit 2 is configured to limit the power supply of each generator and load node when the power source is disconnected from the power system of the generator 101, valid output, invalid output, valid load, invalid load, and voltage control device. Is obtained, and voltage analysis data including them is created.

  FIG. 6 illustrates an example of voltage analysis data created by the transient stability analysis unit 2. FIG. 6 is a diagram illustrating the voltage output from the generator 101 and its effective output. Before the assumed failure, the voltage 401 from the generator 101 was 1.010 (pu), and the effective output 402 was 0.500 (pu). On the other hand, in order to maintain the excessive stability, the excessive stability analysis unit 2 disconnects the generator 101 from the power system. And the excessive stability analysis part 2 calculates | requires the voltage 411 from the generator 101 after a transient stability maintenance control as 0.000 (pu), and calculates | requires the effective output 412 as 0.000 (pu). Further, the transient stability analysis unit 2 also includes the voltage, effective output, invalid output, valid load, invalid load, and operating state of the voltage control device at the generator and load nodes other than the generator 101 that change due to the disconnection of the generator 101. Ask. The excessive stability analysis unit 2 creates voltage analysis data from the information thus obtained.

  The voltage stability analysis unit 3 receives input of voltage analysis data from the transient stability analysis unit 2 when the generator 101 is disconnected from the power system. Then, the voltage stability analysis unit 3 obtains a PV curve at each load node when the generator 101 is disconnected from the power system from the received voltage analysis data. In this case, the voltage stability analysis unit 3 obtains the PV curve under the condition that the voltage control device is locked and the voltage control device does not operate.

  FIG. 7 is a diagram illustrating the transition of the PV curve. The vertical axis in FIG. 7 represents the voltage at the load node 103. Also, the horizontal axis of FIG. 7 represents the load at the load node 103. The load characteristic 500 represents the load characteristic (constant current characteristic) at the load node for which the PV curve is obtained.

  In the load node 103, the PV curve indicated by the PV curve 501 was before the occurrence of the assumed failure. On the other hand, the voltage stability analysis unit 3 acquires a PV curve 502 as a PV curve when a failure occurs and the generator 101 is disconnected from the power system. An operating point 509 that is the intersection of the load characteristic 500 and the PV curve 502 is located below the stability limit that is the apex of the PV curve. In this way, the voltage stability analysis unit 3 confirms the occurrence of a voltage lowering solution at the load node 103, for example. Similarly, in this embodiment, the voltage stability analysis unit 3 confirms the occurrence of a voltage lowering solution at the load node 104, for example.

  Further, the voltage stability analysis unit 3 obtains a difference between the operating point and the stability limit at each load node, and obtains a load node having the obtained difference equal to or less than the threshold value. For example, the voltage stability analysis unit 3 uses 0.0005 (pu) as a threshold value. The wider the difference between the operating point and the stability limit, the greater the voltage stability. However, if the threshold is too wide, it becomes difficult to satisfy the threshold at all load nodes in the power system. Therefore, the threshold value is preferably set according to the operating state of the power system such as an allowable range of voltage stability.

  When there is a load node having a lower voltage solution or a load node whose difference between the operating point and the stability limit is less than or equal to the threshold value, the voltage stability analysis unit 3 adds a power limit and a load limit, and each load node increases the voltage. Have a solution and make the difference between the operating point and the stability limit equal to or greater than the threshold. Here, the voltage stability analysis unit 3 performs power source limitation on the generator 102 and load limitation on the load node 105 illustrated in FIG. 4 in order to maintain voltage stability.

  By the voltage stability maintenance control, the PV curve at the load node 103 becomes the PV curve 503 shown in FIG. The PV curve 503 intersects with the load characteristic 500 at an operating point 504 that is a point above the stability limit 505, and the voltage is increased at the load node 103. Furthermore, the difference P between the operating point 504 and the stability limit 505 is equal to or greater than the threshold value of 0.0005 (pu). Similarly, the voltage stability analysis unit 3 confirms that the voltage increases at the load node 104 and other load nodes and that the difference between the operating point and the stability limit is equal to or greater than the threshold. .

  In this way, the voltage stability analysis unit 3 adds the power source limitation of the generator 102 and the load limitation of the load node 105 as the voltage stability maintenance control to the power source limitation of the generator 101 applied by the excessive stability maintenance control. Decide that.

  The transient stability analysis unit 2 obtains a change with time of the internal phase difference angle of each generator in a state where the power source limit and the load limit by the voltage stability analysis unit 3 are added. For example, the change over time in the internal phase difference angle of each generator in a state where the power source limitation of the generators 101 and 102 and the load limitation of the load node 105 are performed is as shown by a graph 303 in FIG. FIG. 10 is a diagram illustrating the change over time in the internal phase difference angle of the generator after the voltage stability maintenance control. In graph 303, the internal phase difference angle of the generator converges with time. Therefore, the transient stability analysis unit 2 confirms that the transient stability is maintained even after the voltage stability maintenance control. Then, the transient stability analysis unit 2 notifies the voltage stability analysis unit 3 that the transient stability is maintained even after the voltage stability maintenance control.

  Then, the voltage stability analysis unit 3 receiving the information that the transient stability is maintained even after the voltage stability maintenance control from the transient stability analysis unit 2, the voltage of the generator and the load node after the voltage stability maintenance control, The operation status of the valid output, invalid output, valid load, invalid load and voltage control device is obtained, and operation confirmation data including them is created.

  FIG. 8A is a diagram illustrating the voltage output from the generator 102 and its effective output. After the excessive stability control, the voltage 413 output from the generator 102 was 0.982 (pu), and the effective output 414 was 0.501 (pu). On the other hand, in order to maintain voltage stability, the voltage stability analysis unit 3 disconnects the generator 102 from the power system. Therefore, after performing the voltage stability maintenance control, the voltage 421 from the generator 102 is 0.000 (pu) and the effective output 422 is 0.000 (pu) as shown in FIG. 8A. FIG. 8B is a diagram illustrating an effective load and its invalid load in the load node 105. After the excessive stability maintenance control, the effective load 415 in the load node 105 was 6.549 (pu), and the invalid load 416 was 1.308 (pu). On the other hand, in order to maintain voltage stability, the voltage stability analysis unit 3 performs load limitation on the load node 105. Therefore, after the voltage stability maintenance control is performed, the effective load 423 at the load node 105 is 6.091 (pu) and the invalid load 424 is 1.223 (pu) as shown in FIG. 8B.

  The voltage control device operation confirmation unit 4 receives from the voltage stability analysis unit 3 input of operation confirmation data when the power source of the generator 101 and the generator 102 is restricted and the load of the load node 105 is restricted. Then, the voltage control device operation confirmation unit 4 unlocks the voltage control device, and obtains the operation of the voltage control device when the power source of the generator 101 and the generator 102 is restricted and the load of the load node 105 is restricted. . Here, the voltage control device operation confirmation unit 4 confirms that the node connected to the load node 103, the node connected to the load node 106, and the node connected to the generators 101, 102, and 107 are voltage constraint violation nodes. Therefore, the voltage control device operation confirmation unit 4 confirms that the voltage control device connected to the load node 103, the voltage control device connected to the load node 106, and the voltage control device connected to the generators 101, 102, and 107 operate. In this case, each voltage control device performs control to increase the voltage.

  FIG. 9 is a diagram illustrating an operation state of the voltage control device and a change in voltage. In FIG. 9, each voltage control device is represented by the numbers (1050, 1170, 2040) shown in FIG. 4 of the nodes to which the voltage control device is connected. Specifically, the voltage control device represented by the number 1050 is connected to the load node 106. The voltage control device denoted by reference numeral 1170 is connected to the load node 103. Further, the voltage control device denoted by reference numeral 2040 is connected to the generators 101, 102 and 107. Here, for easy understanding, numbers in FIG. 9 representing the voltage control device are described in parentheses after each voltage control device.

  After the voltage stability maintenance control, the voltage control device (1050) connected to the load node 106, the voltage control device (1170) connected to the load node 103, and the voltage control device (2040) connected to the generators 101, 102 and 107 are locked. Is not working. Therefore, each operation state 601, 602 and 603 is 0.000 (pu). The voltage 701 in the voltage control device (1050) connected to the load node 106 is 0.994 (pu). The voltage 702 in the voltage control device (1170) connected to the load node 103 is 0.994 (pu). Furthermore, the voltage 703 in the voltage control apparatus (2040) connected to the generators 101, 102 and 107 is 0.993 (pu). On the other hand, after the operation of the voltage control device, the operation states 604 and 605 of the voltage control device (1050) connected to the load node 106 and the voltage control device (1170) connected to the load node 103 are 0.100. (Pu). The operating state 606 of the voltage control device (2040) connected to the generators 101, 102, and 107 is 0.300. The voltage 704 in the voltage control device (1050) connected to the load node 106 is 1.001 (pu), and the voltage 705 in the voltage control device (1170) connected to the load node 103 is 1.003 (pu). The voltage 706 in the voltage control apparatus (2040) connected to 101, 102, and 107 is 1.002 (pu). In response to these changes, the voltage, active power, effective load, and reactive load of other generators and load nodes in the power system also change.

  Further, the voltage stability analysis unit 3 obtains a PV curve at each load node in a state where the control of the voltage control device by the voltage control device operation confirmation unit 4 is added, each load node has a voltage increasing solution, It is determined whether the difference between the point and the stability limit is equal to or greater than a threshold value. For example, the PV curve of the load node 103 in a state where the voltage control device connected to the load nodes 103 and 106 and the voltage control device connected to the generators 101, 102, and 107 are operated is as shown by the PV curve 506 in FIG. Become. FIG. 11 is a diagram illustrating a PV curve at the load node 103 after the operation of the voltage control apparatus. As shown in FIG. 11, the operating point 507 in the PV curve 506 is a voltage increasing solution. Further, the difference between the operating point 507 and the stability limit 508 in the PV curve 506 is equal to or greater than the threshold value. Here, since all the load nodes in the power system have a voltage increasing solution and the difference between the operating point and the stability limit is greater than or equal to the threshold value, the voltage stability analysis unit 3 is able to stabilize the voltage even after the voltage control device operates. Confirm that the sex is maintained.

  Then, when it is confirmed that the transient stability and the voltage stability are maintained, the voltage control device operation confirmation unit 4 determines the voltage, active power, invalid output, and voltage of each generator and load node from the control information after the voltage device operation control. The operational load of the effective load, the invalid load and the voltage control device is obtained, and the steady state stability confirmation data is created.

  The steady-state stability confirmation unit 5 performs power source limitation on the generators 101 and 102 and load limitation on the load node 105, a voltage control device connected to the load node 103, a voltage control device connected to the load node 106, and the generators 101 and 102. And even if a load changes in the state which operated the voltage control apparatus connected to 107, it is confirmed that the electric power system is stable.

  Then, the control information notifying unit 6 includes a power control for the generators 101 and 102, a load limit for the load node 105, a voltage control device connected to the load node 103, and a load node 106 as stabilization control when an assumed failure occurs. The operation of the connected voltage control device and the voltage control device connected to the generators 101, 102 and 107 is notified to the operator.

  Next, with reference to FIG. 12, the flow of analysis processing by the power system stabilization analyzer according to the present embodiment will be described. FIG. 12 is a flowchart of analysis processing performed by the power system stabilization analysis apparatus according to the embodiment.

  The operator uses the input unit 1 to input conditions for the assumed failure (step S101).

  The transient stability analysis unit 2 examines the transient stability when a contingency failure occurs, and determines the transient stability maintenance control to limit the power supply so that the transient stability can be maintained (step S102).

  The transient stability analysis unit 2 creates voltage analysis data when the transient stability maintenance control is performed (step S103). The transient stability analysis unit 2 outputs the voltage analysis data to the voltage stability analysis unit 3.

  The voltage stability analysis unit 3 receives input of voltage analysis data from the transient stability analysis unit 2. Then, the voltage stability analysis unit 3 examines the voltage stability (step S104). And the voltage stability analysis part 3 determines the voltage stability maintenance control which adds power supply restriction | limiting and load restriction | limiting so that voltage stability can be maintained.

  The excessive stability analysis unit 2 receives the control information after the voltage stability maintenance control. Then, the excessive stability analysis unit 2 determines whether or not the excessive stability can be maintained when the voltage stability maintenance control is performed (step S105).

  When the overstability cannot be maintained (No at Step S105), the overstability analysis unit 2 notifies the voltage stability analysis unit 3 that the overstability cannot be maintained. The voltage stability analysis unit 3 that has received the fact that the excessive stability cannot be maintained changes the voltage stability maintenance control, and returns to step S104.

  If the excessive stability can be maintained (step S105: affirmative), the excessive stability analysis unit 2 notifies the voltage stability analysis unit 3 that the excessive stability can be maintained. The voltage stability analysis unit 3 creates operation confirmation data from the control information after the voltage stability maintenance control (step S106). The voltage stability analysis unit 3 outputs the created operation confirmation data to the voltage control device operation confirmation unit 4.

  The voltage control device operation confirmation unit 4 receives operation confirmation data from the voltage stability analysis unit 3. Then, the voltage control device operation confirmation unit 4 confirms the operation of the voltage control device in the state where the voltage stability maintenance control is performed, and adds the operation of the voltage control device so as to eliminate the voltage constraint violation (step S107). ).

  The voltage stability analysis unit 3 determines whether or not the voltage stability can be maintained after the voltage stabilizer operates (step S108).

  When the voltage stability cannot be maintained (No at Step S108), the voltage control device operation confirmation unit 4 changes the power supply limit and the load limit applied in the voltage stability control, and returns to Step S104.

  On the other hand, when the voltage stability can be maintained (step S108: affirmative), the voltage controller operation confirmation unit 4 creates steady state stability confirmation data from the control information after the voltage controller operation (step S109). ). The voltage control device operation confirmation unit 4 outputs the created operation confirmation data to the steady state stability confirmation unit 5.

  The steady state stability confirmation unit 5 receives the steady state stability confirmation data from the voltage controller operation confirmation unit 4. Then, the steady state stability confirmation unit 5 examines the steady state stability when there is a minute disturbance such as a change in load after the operation of the voltage control device (step S110). Then, the steady state stability checking unit 5 determines whether or not the steady state stability can be maintained (step S111). When the steady state stability cannot be maintained (No at Step S111), the steady state stability confirming unit 5 uses the voltage control device lock control and the voltage constraint violation in the transient stability maintaining control information and the voltage stability maintaining control information. The node generation information is added (step S112) and transmitted to the control information notification unit 6. The control information communication unit 6 outputs the control information received from the steady state stability confirmation unit 5 to a monitor or the like, and notifies the operator of the stabilization control when an assumed failure occurs (step S113).

  On the other hand, when the steady state stability can be maintained (step S111: affirmative), the steady state stability confirmation unit 5 transmits the control information of the state determined to be capable of maintaining the steady state stability to the control information notification unit. 6 to send. The control information notification unit 6 outputs the control information received from the steady state stability confirmation unit 5 to a monitor or the like, and notifies the operator of stabilization control when an assumed failure occurs (step S113).

  As described above, the power system stabilization analysis apparatus according to this embodiment determines the control for maintaining the excessive stability by examining the excessive stability, and then performs the control for maintaining the excessive stability. The voltage stability in the state is examined, and the control that maintains the voltage stability is determined. Thereby, the electric power system stabilization analyzer which concerns on a present Example has an effect that the control which maintains both a transient stability and voltage stability can be shown. In addition, since the power system stabilization analysis apparatus according to the present embodiment performs the respective studies along the time series of the occurrence of the influence on the transient stability and the voltage stability, the stabilization according to the situation at the time of the actual failure occurrence. Control can be sought.

  In the above description, in order to obtain more accurate stabilization control, the operation of the voltage control device and the steady state stability after the voltage control device operation have been confirmed, but the level required for the stabilization control is so high. If not, these need not be performed. In this case, the voltage control device operation confirmation unit 4 and the steady state stability confirmation unit 5 may be omitted. It is also possible to check the operation of the voltage control device but not to check the steady state stability after the operation of the voltage control device. Even in these cases, there is an effect that it is possible to present control that maintains both the excessive stability and the voltage stability.

DESCRIPTION OF SYMBOLS 1 Input part 2 Transient stability analysis part 3 Voltage stability analysis part 4 Voltage control apparatus operation | movement confirmation part 5 Steady state stability confirmation part 6 Control information notification part

Claims (9)

Based on the information data and contingencies representing the power condition in the power system during normal and transient stability analysis unit for determining the transient stability maintenance control for maintaining the transient stability when the contingency has occurred ,
A voltage for maintaining voltage stability when the assumed failure occurs based on the information on the power state and the assumed failure in the power system when the power supply restriction determined by the transient stability analysis unit is performed A power system stabilization analysis apparatus comprising: a voltage stability analysis unit that determines stability maintenance control. The transient stability analysis unit determines, as transient stability maintenance control, execution of power restriction that disconnects some of a plurality of generators arranged in the power system from the power system. Item 2. The power system stabilization analysis apparatus according to Item 1.   The voltage stability analysis unit, as voltage stability maintenance control, a power source restriction that disconnects some of the plurality of generators arranged in the power system from the power system and a load that reduces the demand for electricity in the power system The power system stabilization analysis apparatus according to claim 1 or 2, wherein execution of either one or both of the restrictions is determined. The transient stability analysis unit determines whether or not the transient stability in the power system can be maintained when the voltage stability maintenance control determined by the voltage stability analysis unit is performed. Item 4. The power system stabilization analysis apparatus according to any one of Items 1 to 3. The transient stability analysis unit, based on the information of the voltage stability maintenance control as determined by the data and the voltage stability analysis unit representing the power condition in the power system during normal, the transient stability analysis unit has determined The power system stabilization analysis apparatus according to claim 4, wherein it is determined whether or not the transient stability in the power system can be maintained when the restriction is performed. The power system includes a voltage control device that controls a voltage at a load,
Based on the power state when the transient stability maintaining control and the voltage stability maintaining control are performed, the operation of the voltage control device for maintaining the voltage of each load in the state where the voltage stability maintaining control is performed. A voltage control device operation confirmation unit for determining,
Whether the voltage stability analysis unit can maintain the voltage stability when the operation of the voltage control device determined by the voltage control device operation confirmation unit is performed in the state where the voltage stability maintenance control is performed. The power system stabilization analysis apparatus according to any one of claims 1 to 5, wherein: When the voltage stability can be maintained in a state where the operation of the voltage control device determined by the voltage control device operation confirmation unit is performed in the state where the voltage stability maintenance control is performed, the steady state stability can be maintained. The power system stabilization analysis apparatus according to claim 6 , further comprising a steady-state stability confirmation unit that determines whether or not. Based on the first data representing the power state in the normal power system and the data of the assumed failure, the computer determines the power limit for maintaining the transient stability when the assumed failure occurs,
Causing the computer to generate second data representing a power state when the power supply is limited to maintain the determined transient stability;
On the basis of the second data, the data on the contingency and the data on the power limiting for maintaining the determined transient stability, the power limiting or load limiting for maintaining the voltage stability when the contingent fault occurs. A power system stabilization analysis method characterized by causing a computer to determine one or both of the above. Based on the first data representing the power state in the normal power system and the data of the assumed failure, the power supply limitation for maintaining the transient stability when the assumed failure occurs is determined,
Create second data representing the power state when the power supply restriction is performed to maintain the determined transient stability,
On the basis of the second data, the data on the contingency and the data on the power limiting for maintaining the determined transient stability, the power limiting or load limiting for maintaining the voltage stability when the contingent fault occurs. A power system stabilization analysis program that causes a computer to execute a process for determining one or both of the above.

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