JP2019080364A - Supply and demand adjusting system, supply and demand adjusting method and supply and demand adjusting program - Google Patents

Abstract

To provide a supply and demand adjusting system which can maintain the voltage stability of the power-system for voltage recovery while avoiding a stop of a power generator and realizing cost reduction by performing output control of the power generator when emergently adjusting supply and demand after a system fault.SOLUTION: A supply and demand adjusting system 10 comprises a supply and demand information acquisition part acquiring supply and demand information of a power system 5, an accident type detection part 2 detecting an accident type of a system accident, a formulation part 1 which formulates an output control plan of a supply and demand adjusting generator connected with the power system depending on the supply and demand information and the accident type, and a supply and demand control part 3 which outputs a supply and demand control instruction to the supply and demand adjusting generator according to an output control plan.SELECTED DRAWING: Figure 1

Description

  The embodiment of the present invention relates to a system, method, and program for performing supply and demand adjustment by output control of a supply and demand adjustment generator at the time of emergency supply and demand adjustment after a system accident.

  When a grid accident such as a route break occurs in the power system, the power flow of the transmission line or branch where the accident occurred is diverted and a power flow change occurs such as being superimposed on other branches. Therefore, a large amount of reactive power loss occurs, and the voltage stability of the system becomes weak and the voltage tends to drop. In general, the phenomenon of voltage stability drop occurs when the voltage drops on the order of minutes.

  Even if the accident is eliminated, the demand fluctuates sharply and the steep output of renewable energy occurs before the branch recovers, that is, with less branches and less detour power than normal. If fluctuations occur, the change in tidal current will further increase. As a result, the voltage stability of the power system falls into a more fragile situation.

  As described above, since the voltage stability of the system is weakened after the system accident, it is essential to recover the voltage. Therefore, conventionally, in order to reduce the diverted power flow itself, there is known a control method for maintaining the voltage stability by stopping the power control urgently, that is, the generator. As further voltage recovery measures, local control of voltage reactive power control (VQC) and correction of a controlled quantity based on system information such as power flow and voltage measured online are also proposed.

Patent No. 5424774 gazette Patent No. 1867793

  If it is necessary to shut down the power control, that is, to stop the generator after a system accident, it will be essential to restart the generator after recovery, but restarting the generator will cost a lot of time and work. There is a problem that it requires. In addition, when the stopped generator is a generator for frequency adjustment, there is a disadvantage that the frequency adjustment source is reduced by stopping such a generator. Furthermore, under severe conditions such as main trunk route interruptions of the backbone system, there is a risk that the voltage adjustment will not be sufficient with the electric control alone, and the voltage recovery will be insufficient.

  The embodiment of the present invention is proposed in view of the above situation, and when the supply and demand adjustment is performed urgently after a system accident, the output of the generator is controlled to stop the generator. It is an object of the present invention to provide a supply and demand adjustment system, a supply and demand adjustment method, and a supply and demand adjustment program capable of maintaining voltage stability of a system and achieving voltage recovery while avoiding cost reduction.

In order to solve the above problems, the present embodiment includes the following components (a) to (d).
(a) A feed information acquisition unit that acquires feed information of the power system.
(b) An accident type detection unit that detects an accident type of a system accident.
(c) A formulation unit that formulates an output control plan of a demand-supply adjusting generator connected to the power system according to the power supply information and the type of accident.
(d) A supply and demand control unit that outputs a supply and demand control command to the supply and demand adjustment generator according to the output control plan.
The embodiment of the present invention can be understood as an invention of a demand-supply adjustment method in which the computer executes the processing of each part in the demand-supply adjustment system, and an invention of a supply-demand adjustment program that causes a computer to execute the processing of each part in the demand-supply adjustment system. it can.

Block diagram of the first embodiment Block diagram including supply and demand adjustment generator in the first embodiment Principal part block diagram of the first embodiment Diagram showing the diversion flow after a system accident Diagram showing tidal current change where voltage stability becomes severe after system accident Diagram showing the difference in voltage sensitivity due to the supply and demand adjustment generator A figure showing a rank table in a 1st embodiment Block diagram of the second embodiment A diagram showing a ranking table (supply and demand control target flag and each accident) in the second embodiment EDC block diagram LFC block diagram Block diagram of the third embodiment Graph showing probability distribution of renewable energy output fluctuation and demand fluctuation

First Embodiment
(Constitution)
Hereinafter, the first embodiment will be described in detail with reference to FIGS. 1 to 7. The block diagram of FIG. 1 and FIG. 2 has shown the example of installation of the main apparatuses which comprise the supply-and-demand control system 10 which concerns on 1st Embodiment. A plurality of supply and demand adjustment generators 7 (hereinafter simply referred to as generators 7 and illustrated in FIG. 2) are connected to the power system 5. The supply and demand control system 10 is a system that performs supply and demand adjustment not by stopping the generator 7 at the occurrence of a system accident but by controlling the output of the generator 7, that is, by increasing the generator 7 more. Yes, it consists of a computer, a program that controls it, and peripherals.

  The supply and demand control system 10 includes a power supply information network N for acquiring power supply information of the power system 5, an accident type detection unit 2 for detecting an accident type of a system accident, and each generator according to the power supply information and the accident type. A formulation unit 1 formulates an output control plan 7 and a demand / supply control unit 3 outputs a demand / supply control command to each generator 7 according to the formulated output control plan. The formulation unit 1, the accident type detection unit 2 and the supply and demand control unit 3 are connected to the power system 5 or the power supply information network N by a communication facility 9 such as a signal line.

  In the supply and demand control system 10, feed information such as the connection state of the electric power system 5 and the supply and demand state of electric power is collected via the feed information network N. The feed information network N is a network that outputs feed information of the power system 5 to the formulation unit 1. The accident type detection unit 2 is installed in a substation or the like, and the supply and demand control unit 3 is installed in a power plant or the like. The accident type detection unit 2 is an accident detection terminal device that outputs accident information including the accident type to the formulation unit 1.

  The formulation unit 1 is installed at a location connectable to the power feeding information network N, such as a central power feeding command station or a mains power feeding station. The formulation unit 1 outputs the formulated output control plan of each generator 7 to the demand-supply control unit 3. The demand-supply control unit 3 includes a control terminal device, generates a demand-supply control command according to the output control plan obtained from the formulation unit 1, and transmits the demand-supply control command to each generator 7. The generator 7 is subjected to output control in accordance with the supply and demand control command.

  FIG. 3 is a block diagram showing components included in the formulation unit 1. The formulation unit 1 is provided with a system information acquisition unit 11, an accident condition setting unit 12, a post condition estimation unit 13, a post model generation unit 15, a voltage sensitivity analysis unit 16, a rank determination unit 17, and a rank output unit 18. . Among these, the system information acquisition unit 11 acquires feed information via the feed information network N. The accident condition setting unit 12 inputs accident information including the accident type from the accident type detection unit 2 and sets an accident condition.

  The posterior state estimation unit 13 includes a power flow calculation unit 131 that inputs power supply information and performs power flow calculation, and a stability calculation unit 132 that inputs accident information and that performs stability calculation. The subsequent model generation unit 15 generates a system model for analysis after a system accident occurrence based on the power supply information and the accident information. The voltage sensitivity analysis unit 16 obtains the voltage sensitivity Si of each generator 7 using the analysis system model when a system failure occurs.

  The voltage sensitivity Si of each generator 7 is a change ratio of the system voltage to the supply and demand adjustment amount, assuming that the generator 7 on the electric power system 5 has performed the supply and demand adjustment. A state in which the voltage sensitivity Si is high with respect to supply and demand adjustment is a state in which the voltage of the system tends to rise (it is difficult to decrease), and a state in which the voltage sensitivity Si is low with respect to supply and demand adjustment is a state with respect to the supply and demand adjustment. It is a state that the voltage is hard to rise (it is easy to fall). The order determination unit 17 determines the order of output control of the generator 7 that performs supply and demand adjustment based on the voltage sensitivity Si of each generator 7 determined by the voltage sensitivity analysis unit 16 according to the descending order of the voltage sensitivity Si. The order is determined so that the output control is preferentially performed in order from the generator 7.

  The rank output unit 18 sequentially creates a rank table for performing supply and demand control of the generator 7 in accordance with the rank of the generator 7 determined by the rank determination unit 17, and outputs this to the demand and supply control unit 3. The rank output unit 18 creates a rank table as shown in FIG. 7, for example, in the rank data of the generator 7 determined by the rank determination unit 17, and outputs this to the demand-supply control unit 3.

  FIG. 7 shows a rank table in which outputs after power supply faults of each generator 7, rated output (upper limit of output) and voltage sensitivities Si are arranged in ascending order of supply and demand adjustment rank (first to fourth ranks). The supply and demand adjustment order is the descending order of the voltage sensitivity Si, that is, the first place (Si = + 0.32), the second place (Si = + 0.10), and the third place (Si) = -0.03), 4th position (Si =-0.41). Such a ranking table is substantially the output control plan of the generator 7 formulated by the formulation unit 1. That is, the content of the output control plan of the generator 7 formulated by the formulation unit 1 is defined by the rank of the generator 7 determined by the rank determination unit 17.

  The demand-supply control unit 3 generates a demand-supply control command according to the order table, and transmits the demand-supply control command to each generator 7. The generator 7 is subjected to output control in accordance with the supply and demand control command. That is, since the generator 7 sequentially performs output control (increases) in accordance with the order determined by the order determining unit 17, the power control to stop the generator 7 itself is not performed.

(Action)
In the supply-demand control system 10 having the above configuration, when a system fault occurs, the system information acquisition unit 11 acquires feed information via the feed information network N and outputs it to the power flow calculation unit 131 of the post-state estimation unit 13 Do (power supply information acquisition processing). Further, upon occurrence of a system accident, the accident type detection unit 2 detects and discriminates the accident type of the system accident, and outputs the accident information to the accident condition setting unit 12 (accident type detection process).

  Subsequently, the formulation unit 1 carries out a formulation process of an output control plan of each generator 7. First, the accident condition setting unit 12 sets the accident condition of the accident information input from the accident type detection unit 2 and outputs the accident condition to the stability calculation unit 132 of the posterior state estimation unit 13. The accident conditions include information such as an accident point and an accident appearance. The accident point is, for example, information such as an accident in the A transmission line, and the accident mode is, for example, information such as 1 LC.

  The post-state estimation unit 13 estimates the state of the power system 5 after the power system failure based on the system information input to the tidal current calculation unit 131 and the accident information input to the stability calculation unit 132. That is, in the tidal current calculation unit 131, based on the node branch data, using P and Q designated by the node and P and V as the constraint conditions, using a numerical analysis method such as the Newton Ruffson method or Gauss Seidel method or the DC method Calculate the tidal current state.

  In the power flow calculation, it is necessary to designate P and Q for the PQ designation node and the values of P and V for the PV designation node for all nodes. Therefore, when information of P and Q can not be acquired for all nodes and when information of P and V can not be acquired, information that can not be acquired is complemented using a state estimation method or the like.

  The stability calculation unit 132 performs the transient stability calculation based on the accident condition set by the accident condition setting unit 12 with the power flow calculation result calculated by the flow calculation unit 131 as an initial value. In transient stability calculation, it is necessary to take into consideration the response of the generator and its excitation control system when an accident (disturbance) occurs. Therefore, nonlinear differential equations that model these dynamic characteristics are analytically solved using a Runge-Kutta method or other numerical analysis method, and temporal transitions of the active power of the generator 7, internal phase angle, branch flow, etc. are evaluated. Do.

  In the first embodiment, the posterior state estimation unit 13 includes the tidal current calculation unit 131 and the stability calculation unit 132, and performs tidal current calculation and transient stability calculation to estimate the system state after the system accident. . However, if the system condition after the accident can be measured and the system data necessary for calculating the voltage sensitivity Si required by the voltage sensitivity analysis unit 16 can be created without the power flow calculation and the transient stability calculation, the power flow calculation and It is assumed that the transient stability calculation does not necessarily have to be performed.

  The posterior model generation unit 15 generates a new analysis system model (node branch data) for voltage sensitivity calculation, reflecting the system state after the accident estimated by the posterior state estimation unit 13. When generating the analysis system model, the post-process model generation unit 15 also reflects the system configuration in a state where the circuit breakers of the substations at both ends sandwiching the accident point are opened. That is, the post-process model generation unit 15 generates an analysis system model assuming a case where the voltage stability is more severe, that is, after a system accident.

  Here, the condition of the system in which the voltage stability becomes fragile after the occurrence of the accident until the circuit breakers of the substations at both ends are opened will be described with reference to FIG. In FIG. 4, it is assumed that a two-line ground fault (6LG-O) occurs in a heavy current flow branch. Phase 1 shows the state before the accident occurred. Phase 2 shows the moment when 6LG-O occurs in the heavy current flow branch. Phase 3 shows the state after releasing the circuit breaker at substations on both sides of the accident point after the occurrence of 6LG-O. After transient oscillation due to a system accident converges, the tidal current of the branch that had flowed to the upper side of the figure before the accident is diverted to the lower branch of the figure, and the heavy tidal current is superimposed on the lower branch. .

  That is, compared to before the accident (Phase 1), after the system accident, the heavy current is superimposed only on the lower branch. As a result, more reactive power loss occurs and the voltage stability becomes weak. In view of the situation of the system after the accident as described above, in the present embodiment, the posterior model generation unit 15 can generate an analysis system model and perform an analysis reflecting a weak voltage stability. .

  The voltage sensitivity analysis unit 16 obtains the voltage sensitivity Si of each generator 7 with respect to a change in power flow such that the voltage stability becomes more severe, using the analysis system model generated by the posterior model generation unit 15. Required for the voltage sensitivity analysis unit 16 to calculate the voltage sensitivity Si of each generator 7 after the power flow calculation and the transient stability calculation are performed by the power flow calculation unit 131 and the stability calculation unit 132 of the post-state estimation unit 13 The time is, for example, about 10 seconds.

  An example of the tidal current change in which the voltage stability becomes severe will be described with reference to FIG. In the system state after the accident shown in Phase 3 of FIG. 4, as shown in FIG. 5, the power flow of the lower branch on which the bypass power flow is further increased. In this case, since more reactive power loss occurs, it can be said that severe power flow changes have occurred with respect to voltage stability. As shown in FIG. 5, as a factor of the increase in lower branch flow, there may be a case where the total demand of the system on the right side increases via the accident branch. Therefore, in the system state after the system accident, it is assumed that the total demand of the system on the right side of FIG. 5 has increased by ΔP.

  However, although the pattern shown in FIG. 5 clearly shows an increase in tidal current in which the voltage stability deteriorates, usually the system configuration is often complicated. Therefore, the pattern of the tidal current increase in which the voltage stability deteriorates is not as clear as in the example of FIG. 5, and it may be difficult to understand the tidal current increase in which the voltage stability deteriorates. In such a case, it may be assumed that the total demand of the entire system is increased by ΔP instead of the total demand of the system on the right side of FIG.

  In addition, with the off-line analysis, for the accident pattern (released branch), the tidal current change in which the voltage stability becomes severe and the change in demand (or renewable energy) causing the tidal current change are obtained in advance. It may be In addition, when the power flow change and the demand fluctuation can be predicted at the central power supply command center or the like, the prediction may be used to obtain the voltage sensitivity Si of each generator 7.

The voltage sensitivity analysis unit 16 obtains the voltage sensitivity Si when each generator 7 adjusts supply and demand with respect to the demand increase ΔP based on the following equation (1).
Si = ΔV / ΔPi (1)
Si: Voltage sensitivity ΔPi to supply and demand adjustment of supply and demand adjusting generator i: Supply and demand adjustment amount of supply and demand adjusting generator i ΔV: System voltage change when total demand increases by ΔP and supply and demand adjustment of supply and demand adjusting generator i is performed (Voltage after total demand change-Voltage before total demand change)

  ΔV is a system voltage change when the total demand of the system increases by ΔP and the supply and demand adjustment of the supply and demand adjustment generator i is adjusted, and can be calculated by the above-described tidal current calculation unit 131. As an index of the grid voltage, an average value of voltages of the entire grid, a minimum value of voltages of the entire grid, a voltage of a node whose voltage stability is to be monitored, and the like can be considered. The voltage sensitivity analysis unit 16 obtains the voltage sensitivity derived from the above equation (1) for all the generators 7 for supply and demand adjustment.

  The order determination unit 17 determines the order of control of each generator 7 according to the descending order of the voltage sensitivity Si of each generator 7 determined by the voltage sensitivity analysis unit 16. The descending order of the voltage sensitivity Si is to make the voltage increase amount with respect to the supply and demand adjustment larger in order (that is, the order in which the voltage is easier to increase) or the order in which the voltage decrease amount with respect to the supply and supply adjustment becomes smaller in order (that is, the order in which the voltage is difficult to drop). That is, according to the order determined by the order determining unit 17, the generator 7 with a large voltage rise (voltage recovery) by supply and demand adjustment is given priority, or the generator 7 with a small voltage drop is given priority by supply and demand adjustment. It means that the demand and supply will be adjusted.

  How to determine the order of the generators 7 will be described with reference to FIG. 6 by taking high (large) and low (small) examples of the voltage sensitivity Si of the generator 7 with respect to the change in output. In FIG. 6, when demand and supply are adjusted with the generator 7 on the right side of the accident point with respect to the increase in demand of the system shown in FIG. 5 (1) ... generator on the upper side of FIG. When the demand and supply are adjusted in (2) ... Figure 6 shows the lower side.

  In (1), by increasing the output of the generator 7 on the right side of the area where demand for the system has increased, the increase in output serves to offset the demand, and it is possible to suppress the increase in the power flow of the heavy flow branch. . As a result, the voltage sensitivity Si of the generator 7 becomes large, the system voltage easily rises, and voltage recovery can be achieved. On the other hand, in (2), since the output of the generator 7 on the left side of the accident point is increased, the increase in output spurs the increase in tidal flow of the heavy flow branch. Therefore, the voltage sensitivity Si of the generator 7 becomes small, and the system voltage hardly rises, and the voltage recovery becomes difficult.

  In this embodiment, since the output control of the generator 7 is sequentially performed in accordance with the order determined by the order determining unit 17, there is no case where a plurality of generators 7 having different orders perform output control simultaneously. Therefore, for example, the demand and supply adjustment is performed with the generator 7 of G1 (1st place in the order table in FIG. 7) whose rank is high, and when the generator 7 of G1 reaches the rated output (output upper limit) Supply and demand adjustment is performed with the generator 7 of the lower G2 (the second place in the ranking table in FIG. 7).

  Then, when the generator 7 of G2 reaches the rated output (output upper limit), the supply and demand adjustment is performed by the generator 7 of G3 (third place in the order table of FIG. 7) which is the next order. In this example, when the generator 7 during supply and demand adjustment reaches the rated output (output upper limit), the generator 7 shifts to the next-ranked generator 7. However, the present invention is not limited to this. When there are operating restrictions of the generator 7 such as, the order output unit 18 creates an order table in consideration of those restrictions.

  The demand-supply control unit 3 generates a demand-supply control command according to the output control plan of each generator 7 formulated by the formulation unit 1, that is, the demand-supply control command according to the order table (see FIG. 7) prepared by the order output unit 18 Is transmitted to each generator 7 on the power system 5 (demand and supply control process) when the demand increases after the system accident. Each generator 7 performs supply and demand adjustment based on the supply and demand control command.

  In the present embodiment, the voltage sensitivity Si is calculated on the assumption that the voltage stability after a system accident is severe (increase in power flow of heavy flow branches), and the order of controlling the generator 7 is determined based on this. In some cases, the equal voltage stability may not be severe, as the flow of the heavy flow branch decreases in reverse after the accident. In such a case, it is sufficient to apply the usual supply and demand adjustment rules.

(effect)
In the supply and demand control system 10 according to the first embodiment, when the accident type detection unit 2 detects a system accident and outputs the accident information, the voltage sensitivity analysis unit 16 takes in the accident information and the generator 7 adjusts the supply and demand. The voltage sensitivity Si of each generator 7 with respect to the supply and demand adjustment amount when it is assumed is calculated. The order determination unit 17 determines the order of the generators 7 used for supply and demand adjustment based on the voltage sensitivity Si calculated by the voltage sensitivity analysis unit 16.

  Therefore, in a situation where voltage stability from occurrence of an accident to restoration is severe, it is possible to determine the order of control of the generator 7 for supply and demand adjustment according to the voltage sensitivity Si. Then, the demand-supply control unit 3 outputs the demand-supply control command to the generator 7 according to the output control plan, ie, the order table, and the generator 7 receiving the demand-supply control command performs output control according to the order table.

  In the first embodiment, the voltage sensitivity Si of each generator 7 with respect to the demand increase ΔP of the system is determined, and the order of the generators 7 that perform supply and demand adjustment is determined according to the descending order of the voltage sensitivity Si. The output control can be performed sequentially from the generator 7 with the larger voltage sensitivity Si. As a result, it becomes possible to carry out supply and demand adjustment that is effective for maintaining voltage stability at the time of a system accident, and it is possible to achieve system voltage recovery.

  In the first embodiment, since the order of the generator 7 is only determined according to the calculated voltage sensitivity Si, the influence of the supply-demand adjustment by the generator 7 on the system voltage at the time of a system accident in a complicated system is difficult to grasp As a result, it is possible to accurately carry out supply and demand adjustments that are effective in maintaining voltage stability in the event of a system fault. That is, in the first embodiment, the voltage sensitivity analysis unit 16 analytically determines the voltage sensitivity Si with respect to the demand increment ΔP, and the order determination unit 17 determines the order of supply and demand adjustment in descending order of the voltage sensitivity Si. doing. For this reason, even if the system configuration is complicated and it is difficult to understand the influence of the supply-demand adjustment of the generator 7 on the system voltage, it is effective for maintaining the voltage stability at the time of a system accident without being confused by the complexity of the system configuration. Supply and demand adjustments can be easily implemented.

  In addition, the phenomenon of voltage stability decline after a system accident occurs on the order of minutes, but from power flow calculation and transient stability calculation in post-state estimation unit 13 to voltage sensitivity Si calculation in voltage sensitivity analysis unit 16 The time required is about 10 seconds. Therefore, the supply and demand adjustment by the output control of the generator 7 can be performed promptly and reliably.

  According to such a first embodiment, in the emergency supply and demand adjustment after the system accident, the stop of the power control, that is, the generator, is avoided, and the voltage stability after the system accident by the supply and demand adjustment of the generator 7 is obtained. It becomes possible to maintain. Further, since there is no need to implement power control, it is not necessary to reactivate the generator 7 at the time of restoration, and the cost can be reduced both in time and in work. Furthermore, by avoiding the stop of the generator 7, there is no concern that the frequency adjustment source will be reduced, and the risk of lack of phase change input under severe conditions such as main trunk route disconnection of the backbone system is also eliminated.

  As described above, the present embodiment in which the output control plan of the generator 7 is formulated by the formulation unit 1 is not only maintaining the voltage stability as an alternative means of the electric control, but also adjusting the limited amount of input. Multiple benefits such as avoiding the use of phase equipment, reducing human costs, and shortening the time to restart can be realized.

  Furthermore, since the order output unit 18 sequentially creates an order table for performing supply and demand control of the generator 7 according to the order determined by the order determination unit 17, a plurality of generators 7 having different orders are simultaneously supplied and received. There is nothing to do. Therefore, by operating the generator 7 to the rated output (output upper limit), supply and demand control can be efficiently performed. Moreover, since the voltage sensitivity analysis unit 16 determines the voltage sensitivity Si to the tidal current change that makes the voltage stability more severe, the voltage stability can be achieved by adjusting the supply and demand by the generator 7 under severe tidal conditions that can be assumed after the accident. It is possible to maintain sex.

Second Embodiment
(Constitution)
The basic configuration of the second embodiment is similar to that of the first embodiment. Therefore, hereinafter, the configuration of the second embodiment will be described with a focus on differences from the configuration of the first embodiment, using FIGS. 8 to 11. The second embodiment reflects the supply and demand adjustment by the generator 7 based on the voltage sensitivity Si described above for steady state supply and demand adjustment, for example, LFC (load frequency control) and EDC (optimal economic load distribution control). It is intended to

  As shown in FIG. 8, the formulation unit 20 of the supply and demand control system 10 according to the second embodiment includes a threshold setting unit 21 that sets a threshold of voltage sensitivity Si and a generator 7 based on the threshold of voltage sensitivity Si. A flag determination unit 22 is provided which determines a supply and demand adjustment target flag for each unit. In the formulation unit 1 of the first embodiment, the output power control plan of the generator 7 is formulated by the rank determination unit 17 deciding the order. However, in the formulation section 20 of the second embodiment, each generator 7 is selected. The output control plan of the generator 7 is formulated by determining the supply and demand adjustment target flag 23.

  As shown in the table in FIG. 9, the threshold setting unit 21 sets the threshold of the voltage sensitivity Si to 0 or more, and the flag determination unit 22 sets the supply and demand control target flag = 0 (OFF) if the voltage sensitivity Si is less than 0. If the voltage sensitivity Si is 0 or more, it is determined that the supply and demand control target flag = 1 (ON). In the table of FIG. 9, the generators 7 of G1 and G2 have the demand / supply control target flag = 1 (ON), and the generators 7 of G3 and G4 have the demand / supply control target flag = 0 (OFF).

  The supply and demand control target flag is reflected as shown in FIG. 10, for example, in EDC (optimized economic load distribution control). The EDC is a control that calculates the power distribution at which the fuel cost of the EDC target aircraft is low, in accordance with the total demand fluctuation assumed several minutes ahead (for example, 5 minutes). FIG. 10 shows a simple control routine of a general EDC except for the supply and demand control target flag 23 formulated by the formulation unit 20. The supply and demand control target flag 23 is multiplied by the EDC ON-OFF flag 24 indicating the target and non-target of the EDC. As a result, the generator 7 which makes the voltage sensitivity Si small and deteriorates the voltage stability is out of the target of EDC.

  Further, the supply and demand control target flag may be reflected on LFC (load frequency control) as shown in FIG. FIG. 11 shows a general LFC (load frequency control) control routine excluding the supply and demand control target flag 23. In the case of LFC, as shown in FIG. 11, the demand / supply control target flag 23 formulated by the formulation unit 11 is multiplied by the sharing ratio. As a result, the generator 7 which has a small voltage sensitivity Si and deteriorates the voltage stability is excluded from the target of LFC. In the second embodiment, the supply and demand control target flag 23 is set to 0 or 1, but the sharing ratio may be continuously changed as a continuous value of 0 to 1.

(Action and effect)
In the supply and demand control system 10 according to the second embodiment, the threshold setting unit 21 sets the threshold of the voltage sensitivity Si in the formulation unit 20, the flag determination unit 22 determines the supply and demand control target flag 23, and The generator 7 having the voltage sensitivity Si which does not reach is excluded from the generator 7 for supply and demand adjustment. Therefore, on the premise that supply and demand adjustment at steady times such as LFC and EDC is performed under severe conditions of voltage stability from a system accident to restoration, the power generation corresponding to the following (a) and (b) Output control of machine 7 can be avoided.

(a) Generator 7 that contributes little to voltage rise (voltage recovery) by adjusting supply and demand
(b) Generator 7 that greatly contributes to voltage drop by adjusting supply and demand
According to such a second embodiment, while performing supply and demand adjustment at steady state such as LFC and EDC, in the emergency after a system accident, only the generator 7 contributing to voltage recovery is focused, and output control is efficiently performed. Voltage stability after a system fault can be further improved.

Third Embodiment
(Constitution)
The basic configuration of the third embodiment is similar to that of the first embodiment. Therefore, in the following, the configuration of the third embodiment will be described focusing on differences from the configuration of the first embodiment, using FIGS. 12 and 13.

  As shown in FIG. 12, in the supply and demand control system 10 according to the third embodiment, the re-energy change estimation unit 32 that estimates the output change of the renewable energy (hereinafter simply referred to as re-energy) in the formulation unit 30 and A demand change estimation unit 33 is provided to estimate a change in grid demand. The re-energy change estimation unit 32 and the demand change estimation unit 33 are connected to the voltage sensitivity analysis unit 16.

  The re-energy change estimation unit 32 and the demand change estimation unit 33 estimate a change based on a probability distribution based on past actual data (variation data). The image of the probability distribution of the re-energy and the demand based on the past performance data in the re-energy change estimation part 32 and the demand change estimation part 33 is shown in FIG. The left figure of FIG. 13 shows the probability distribution of re-energy, and the right figure shows the probability distribution of demand.

  The fluctuation on the horizontal axis indicates the fluctuation results for a certain period, and the “certain period” mentioned here is, for example, a time domain (several minutes or accident recovery to maintain voltage stability after a system accident by supply and demand control of the generator 7 Time) can be considered. In addition, about the probability distribution of re-energy and demand, it is good to analyze in advance from past actual data and to see it as a distribution that reflects actual data of all time, and actual data for every time and every season It may be viewed as a reflected distribution.

  The re-energy change estimation unit 32 determines the assumed widths σ1 and σ2 of the + side fluctuation and the − side fluctuation in the re-energy, and the demand change estimation unit 33 sets the assumed width σ 3 of the + side fluctuation and the − side fluctuation in the system demand Determine σ 4 The expected widths σ1 and σ2 of the re-energy may be fluctuations at one representative position, or may be the total value of the entire re-energy. In the case of the total value of the entire re-energy, it is conceivable to divide the assumed widths σ1 and σ2 by the rating of each device or the like.

  Similarly, the assumed widths σ3 and σ4 of the demand may be fluctuations at one representative site, or may be a total demand value. In the case of the total demand value, a method of dividing the assumed widths σ3 and σ4 by the contract power of the customer may be considered. In the case where there are multiple renewable energy or customers who want to consider the fluctuation, the + side fluctuation and the − side fluctuation for a plurality of places may be considered.

The following methods (1) to (3) can be considered as the method of determining the assumed widths σ1 to σ4 in the change estimation units 32 and 33.
(1) When determined from the expected value determined from the occurrence probability of fluctuation and voltage fluctuation
(2) When assuming a wider fluctuation range to assume a more severe case
(3) In the case of a fixed standard deviation (for example, 1σ, 2σ, etc.)

  The combinations of assumed fluctuation patterns assumed after the assumed widths σ1 to σ4 are determined by the change estimation units 32 and 33 are (σ1, σ3), (σ1, σ4), (σ2, σ3), (4) It is σ2, σ4). The voltage sensitivity analysis unit 16 calculates the voltage sensitivity Si of each generator 7 by reflecting the above four combinations in the analysis system model after analysis generated by the aft model generation unit 15 and performing the power flow calculation. Do.

  The voltage sensitivity analysis unit 16 analyzes the voltage fluctuation when each generator 7 absorbs the power flow fluctuation of the target pattern as the voltage sensitivity Si, targeting the pattern with the most severe voltage stability from the combination of the four assumed fluctuation patterns. Do. The order determining unit 17 determines the order of supply and demand adjustment of the generator 7 in accordance with the voltage sensitivity Si, and the like, which are the same as those in the first embodiment.

(Action and effect)
In the third embodiment, by providing the voltage sensitivity analysis unit 16 with the reenergy change estimation unit 32 and the demand change estimation unit 33, a fluctuation pattern that degrades the voltage stability from the probability distribution of the reenergy and the fluctuation of demand is obtained. Assuming that the order of supply and demand adjustment of the generator 7 can be determined with certainty. Therefore, it is possible to maintain the voltage stability by adjusting the supply and demand by the generator 7 even under tidal conditions in which the voltage stability becomes more severe, which can be assumed after the accident.

  In particular, re-energy may fluctuate significantly in a short period of time and is considered to adversely affect voltage stability as the amount of re-energy introduction increases. Therefore, in the present embodiment, supply and demand control can be implemented with strict consideration to the range of fluctuation of the renewable energy, and after the system accident, the fluctuation of the regenerative energy causes severe fluctuation of the power flow with respect to the voltage stability. However, the possibility that voltage stability can be maintained can be further enhanced.

(Other embodiments)
The above embodiment is an example and does not limit the scope of the invention, and can be implemented in other various forms, and various omissions and replacements can be made without departing from the scope of the invention. , Can make changes. These embodiments and modifications thereof are included in the invention described in the claims and the equivalents thereof as well as included in the scope and the gist of the invention.

  A method for executing the processing of each of the above-described units, a program, and a recording medium recording the program are also an aspect of the embodiment. Further, the range of processing by hardware and the range of processing by software including a program are not limited to a specific mode. Furthermore, any of the above-described units can be configured as a circuit that implements each process.

  For example, although the order in which the generator 7 is controlled is determined according to the voltage sensitivity Si in the first embodiment, the output holding unit of the generator 7 may be provided in the formulation unit. For example, when the tidal current change after the accident deteriorates the voltage stability of the system, for example, in the case of the generator 7 where the voltage sensitivity Si is negative (the voltage stability is deteriorated), the output holding unit of the generator 7 The output of the generator 7 is set in the downward direction.

  On the contrary, when the power flow change after the accident improves the voltage stability of the system, for example, if the voltage sensitivity Si is positive (i.e., the voltage stability is improved), the output change unit of the generator 7 The output of the generator 7 is in the upward direction, and the output of the generator 7 is switched. According to the embodiment having such an output switching unit, it is possible to more flexibly maintain the voltage stability at the time of a system accident.

  The output control plan formulated by the formulation unit is not limited to one formulated based on real-time system information, but may be preset and stored in a database or the like. In addition, the formulation unit may review the output control plan according to the recovery time until the accident is recovered, the number of accident points, and the like. In the third embodiment, the re-energy change estimation unit 32 and the demand change estimation unit 33 are added to the components of the first embodiment, but the re-energy change estimation unit 32 and the demand are added to the components of the second embodiment. The change estimation unit 33 may be added.

1, 20, 30 ... Development unit 2 ... Accident type detection unit 3 ... Supply and demand control unit 5 ... Power system N ... Power supply information network 7 ... Generator 9 ... Communication equipment 10 ... Supply and demand control system 11 ... System information acquisition unit 12 ... Accident Condition setting unit 13 ... Post-state estimation unit 131 ... Power flow calculation unit 132 ... Stability calculation unit 15 ... Post-model generation unit 16 ... Voltage sensitivity analysis unit 17 ... Rank determination unit 18 ... Rank output unit 21 ... Threshold setting unit 22 ... Flag Determination unit 23 ... supply and demand control target flag 24 ... ON-OFF flag 32 ... re-energy change estimation unit 33 ... demand change estimation unit

Claims (12)

A feed information acquisition unit that acquires feed information of a power system;
An accident type detection unit that detects an accident type of a system accident;
A formulating unit for formulating an output control plan of a demand-supply adjusting generator connected to the electric power system according to the feeding information and the type of accident;
A supply and demand control unit that outputs a supply and demand control command to the supply and demand adjustment generator according to the output control plan;
Supply and demand adjustment system with. The above-mentioned development department
A posterior model generation unit that generates a system model for analysis after a system accident occurrence based on the feeding information and the accident type;
Voltage sensitivity that analyzes the voltage sensitivity of each of the supply and demand adjustment generators when it is assumed that the supply and demand adjustment generator connected to the electric power system has performed supply and demand adjustment at the occurrence of a system accident based on the analysis system model And an analysis unit,
The supply and demand adjustment system according to claim 1, wherein an output control plan of the supply and demand adjustment generator is formulated based on the voltage sensitivity.   The supply and demand adjustment system according to claim 2, wherein the formulation unit has a rank determination unit that determines a rank when the supply and demand adjustment generator performs supply and demand adjustment according to the voltage sensitivity.   The demand adjustment system according to claim 3, wherein the order determination unit creates an order table based on the order. The voltage sensitivity analysis unit
An accident condition setting unit that sets an accident condition based on the accident type;
The supply and demand adjustment system according to any one of claims 2 to 4, further comprising: a stability calculation unit that calculates the stability of the power system based on the accident condition and outputs the stability to the posterior model generation unit. . The voltage sensitivity analysis unit
A grid information acquisition unit that acquires grid information of a power grid;
The power supply adjustment system according to claim 5, further comprising: a power flow calculation unit that calculates a power flow value of a power system based on the power system information and outputs the power flow value to the stability calculation unit.   7. The voltage sensitivity analysis unit according to any one of claims 2 to 6, wherein the voltage sensitivity analysis unit analyzes the voltage sensitivity of the system when the supply and demand adjustment generator performs supply and demand adjustment with respect to the tidal current change after the accident that deteriorates the voltage stability of the system. Supply and demand adjustment system described in.   The supply and demand adjustment system according to any one of claims 1 to 7, wherein the formulation unit has a flag determination unit that determines a supply and demand adjustment target flag for each of the supply and demand adjustment generators. The formulation unit has an output transfer unit of the supply and demand adjustment generator,
The output change-over unit changes the voltage stability of the system after the accident so that the output of the demand-supply adjusting generator is lowered when the change in power flow after the accident deteriorates the voltage stability of the system. The supply and demand adjustment system according to any one of claims 1 to 8, wherein the output of the supply and demand adjustment generator is switched so as to increase the output of the supply and demand adjustment generator if the output of the supply and demand adjustment generator is increased.   The supply-demand adjustment system according to any one of claims 1 to 9, further comprising at least one of a re-energy output change estimation unit that estimates an output change of renewable energy and a demand change estimation unit that estimates a change in grid demand. Power supply information acquisition processing for acquiring power supply information of a power system;
Accident type detection processing for detecting an accident type of a system accident;
A formulation process for formulating an output control plan of a supply / demand adjustment generator connected to the power system according to the feeding information and the type of accident;
Supply and demand control processing for outputting a supply and demand control command to the supply and demand adjustment generator according to the output control plan;
Supply and demand adjustment methods performed by the computer. Power supply information acquisition processing for acquiring power supply information of a power system;
Accident type detection processing for detecting an accident type of a system accident;
A formulation process for formulating an output control plan of a supply / demand adjustment generator connected to the power system according to the feeding information and the type of accident;
Supply and demand control processing for outputting a supply and demand control command to the supply and demand adjustment generator according to the output control plan;
Supply and demand adjustment program to be run on a computer.

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