JP6659497B2 - Electric machine selection method, electric machine selection program and recording medium - Google Patents

Description

  An embodiment of the present invention relates to a method for selecting a control in a power system stabilization device, a control program for a control, and a recording medium for the program.

  Generally, when a sudden imbalance in supply and demand occurs due to an accident or the like in a power system, a generator in the system loses synchronism. Generator out-of-synchronization is mainly caused by the fact that the electrical output remains low relative to the mechanical input of the generator, the rotational speed of the generator increases, and the phase relationship with other generators is lost. Factors. Therefore, if the electrical output with respect to the mechanical input can be temporarily increased, the rotation speed of the generator can be reduced and the phase relationship with other generators can be prevented from being disrupted. Power limitation (hereinafter referred to as power control) is a stabilization method that uses the effect that the load sharing (power generation output) of a shut-off generator is shared by the remaining generators, thereby temporarily increasing the electrical output. It is.

  Conventionally, as an index for selecting a generator to be controlled (hereinafter referred to as a "electric control") (hereinafter referred to as a "electric control selection index"), it is calculated from the calculation result of a system transient stability simulation. Acceleration indicators that use energy to increase the rotational speed of the generator (hereinafter referred to as acceleration energy) are used in many systems. In the acceleration index, we consider that generators with higher acceleration energy are more likely to lose synchronism, so we calculate the acceleration energy of each generator as an index when selecting a generator, and give priority to generators with higher acceleration energy as generators. To choose.

JP 2004-282887 A JP 2010-057253 A JP 2013-066262 A JP 2014-075939 A

  In the case of performing electric control using the magnitude of the acceleration energy as an index as described above, for example, two generators, a generator G1 having a large acceleration energy and a generator G2 having a small acceleration energy, are selected as the electric regulators, Moreover, the transient stability cannot be maintained by the power control of the generator G1 alone, and the transient stability can be maintained by the power control of the generator G2 only.

  In such a case, by using the above-mentioned acceleration index, the generator G1 whose acceleration energy is greatly accelerated is selected first. However, since the transient stability cannot be maintained by the generator G1 alone, the generator G2 that is accelerating next next is additionally selected as the electric control machine. Therefore, even in the case where the transient stability can be maintained only by the power control of the generator G2, the two generators G1 and G2 are selected as the power generators by using the acceleration index described above. Electricity control will be performed.

  As described above, in the related art, since the electrical control device is selected only by the acceleration index, when the generator that has a low acceleration energy and accelerates relatively slowly becomes a main cause of the deterioration of the transient stability of the system, the It was not possible to preferentially select a generator as a control.

  In order to improve this point, there is also known a prior art in which the relationship between acceleration energy and energy for reducing the rotation speed of a generator after an accident is eliminated or after electric control (hereinafter referred to as deceleration energy) is used as an electric control selection index. ing. According to this conventional technology, it is considered that a generator with a smaller difference between acceleration energy and deceleration energy is more likely to lose synchronism, and the difference between the acceleration energy and deceleration energy of each generator is calculated using simulation results from the time when the accident occurred until immediately after the accident was removed. Is calculated, and the generator having the smaller difference is selected as an electric power control target.

In this case, active power P0 of the accident before the target _generator, active power Pc immediately after the accident removal, accident immediately after the active power Pf1, data on such active power Pf2 immediately before the accident removal, prior transient stability simulations And a power phase difference angle curve during and after the accident, using information on the phase angle (phase difference angle δ) of the generator calculated from the stored data and information on the stored generator output. (Referred to as P-δ curve), and acceleration energy is calculated based on the estimated P-δ curve.

  For example, as shown in FIG. 1A, in the P-δ curve (1) before the accident, the P-δ curve (2) during the accident, and the P-δ curve (3) after the accident was eliminated, The portion surrounded by the active power P0 of the target generator, the active power Pf1 immediately after the occurrence of the accident, and the active power Pf2 immediately before the removal of the accident indicates the acceleration energy. On the other hand, the portion surrounded by the active power P0 of the target generator before the occurrence of the accident, the active power Pc immediately after the removal of the accident, and the P-δ curve (3) after the removal of the accident indicates the deceleration energy. Therefore, the difference between the acceleration energy and the deceleration energy is calculated by estimating each of the P-δ curves (1) to (3), and a generator having a small difference is selected as a power control target.

  However, as shown in FIG. 1 (b), the peak of the P-δ curve (3) after the accident is eliminated is larger than the active power Pc immediately after the accident is eliminated, and the active power P0 of the target generator before the accident is generated. Some generators have similar characteristics. In this type of generator, the peak of the P-δ curve (3) is smaller than the active power P0 of the target generator before the occurrence of the accident. There is no portion surrounded by the P-δ curve (3), and the deceleration energy after the accident is eliminated becomes zero. As a result, while the deceleration energy is used as the selection index of the electric control, the evaluation is actually performed only for the acceleration energy, and the result may be the same as the electric machine selection method using only the acceleration index.

  The embodiment of the present invention selects a generator suitable for maintaining the required transient stability even in a power system including a generator having such a characteristic that the deceleration energy after the accident is eliminated becomes zero. A method for selecting a control device is provided.

The electronic device selection method according to the embodiment of the present invention has the following configuration.
(1) A generator suitable for power supply restriction is selected from a plurality of generators connected to the system and disconnected from the system.
(2) For each of the plurality of generators,
(a) a process of calculating acceleration energy for increasing the rotation speed immediately after the occurrence of an accident;
(b) a process of calculating deceleration energy for reducing the rotation speed of the generator after the removal of the accident or after electric control;
(c) calculating a potential deceleration energy that can reduce the increase in the rotation speed with respect to the increase in the rotation speed of the generator before the accident occurs;
Execute
(3) Using an electric control selection index based on the acceleration energy, deceleration energy, and potential deceleration energy obtained in each of the calculation processes,
(a) If the deceleration energy cannot be calculated, or if the deceleration energy can be calculated and the deceleration energy is smaller than the acceleration energy, the control device selection processing is performed based on the difference between the potential deceleration energy and the acceleration energy. Do
(b) If the deceleration energy can be calculated and the deceleration energy is equal to or more than the acceleration energy, the control device selection process is performed based on the difference between the deceleration energy and the acceleration energy.

  Embodiments of the present invention also include a program and a computer-readable recording medium on which the program is recorded.

5 is a graph illustrating acceleration energy, deceleration energy, and potential deceleration energy. FIG. 2 is a diagram illustrating a configuration of the embodiment. The figure explaining the structure of energy index calculation processing 2. The figure explaining the structure of the electrical machine selection process 3. The figure explaining the parameter extracted from a simulation result. The figure explaining the state change of the target generator of Pcmax <= P0 and Psmax <= P0 (Psmax> = Pcmax). The figure explaining the state change of the target generator of Ps <= P0 by Pcmax <= P0 and Psmax> P0 (Psmax> = Pcmax). The figure explaining the state change of the target generator of Ps> P0, when Pcmax <P0 and Psmax> P0 (Psmax> Pcmax). The figure explaining the state change of the target generator of Pc <P0 and Ps <P0 (Ps> = Pc), when Pcmax> P0. The figure explaining the state change of the target generator of Pcmax> P0, Pc <P0, and Ps> P0 (Ps> = Pc). The figure explaining the state change of the target generator of Pc> P0 (Ps> = Pc) with Pcmax> P0.

  In the embodiment of the present invention, the acceleration energy and the deceleration energy used as the control selection index are as shown in FIG. The potential deceleration energy has such a characteristic that the peak of the P-δ curve (3) after the accident is eliminated is larger than the active power Pc immediately after the accident is eliminated, and is equal to the active power P0 of the target generator before the occurrence of the accident. The size is calculated for the generator, and its size is the portion filled with the diagonal grid in FIG. That is, starting from the phase angle δc of the active power Pc immediately after the accident removal in the P-δ curve (3) after the accident removal, the active power P0 of the target generator before the accident and the P-δ curve (1 ).

[1. First Embodiment]
[1-1. Constitution]
The configuration of the present embodiment will be described with reference to FIGS.

  As shown in FIG. 2, the selection method of the present embodiment includes a transient stability calculation simulation process 1 for calculating the transient stability of the target system, an energy index calculation process 2 for calculating a power control selection index by energy calculation, The control system includes an electrical machine selecting process 3 for selecting an electrical machine using the index calculated in the energy index calculating process 2.

  As shown in FIG. 3, the energy index calculation process 2 includes a simulation result extraction process 21, a P-δ curve calculation process 22, and a power control selection index calculation process 23. The simulation result extraction process 21 extracts parameters used for calculating the power control selection index from the simulation result obtained by the transient stability process 1. The P-δ curve calculation processing 22 calculates the vertex P0max of the P-δ curve before the occurrence of the accident, the vertex Pcmax of the P-δ curve after the removal of the accident, and the vertex Psmax of the P-δ curve after the electric control. The power selection index calculation processing 23 calculates acceleration energy, deceleration energy, and potential deceleration energy.

  The electric machine selection processing 3 includes electric power control target generator classification processing 31 and 32 for performing electric generator classified processing based on acceleration energy and deceleration energy shown in FIG. 4, and electric power control from among the classified electric generators. The control system includes electric machine selection processing 33, 34, 35 for selecting a generator based on the selection index, and selection judgment processing 36, 37 for judging whether the electric machine can be selected.

[1-2. Action]
The operation of the embodiment will be described with reference to FIGS. 5A to 11, (a) is a simulation waveform, (b) is a P-δ curve created based on the simulation waveform, (1) is before the accident, (2) is during the accident, (3) is a P-δ curve after the accident has been eliminated, and (4) is a P-δ curve after the electric control.

[1-2-1. Simulation processing]
In the transient stability calculation simulation processing 1, a tidal current is calculated for a system model obtained from state determination calculation, which is a known technique from arbitrary online SV / TM information, to calculate a tidal current state of a target section. That is, the online SV / TM information is system information in the power system collected at a fixed cycle by the data collection device, and the data collection device communicates with various devices installed at each electric station in the power system via a network. It is connected online and collects SV information and TM information as system information. The SV information is operation information of a circuit breaker CB, a line switch LS, a protection relay, and the like in the power system, and the TM information is information of a bus voltage, a transmission line, a transformer, a generator, and other target systems. This is information on the tide of each location.

  The transient stability calculation simulation process 1 performs detailed system analysis on a target section of a system model in a preset accident case (for example, target device, operation state, system state, accident aspect, accident sequence, accident sequence time, etc.). Perform transient stability calculations. As a result of the detailed transient stability calculation, an energy index calculation process 2 and a control device selection process 3 are performed for an unstable accident case that requires power control.

[1-2-2. Energy index calculation processing]
In the simulation result extraction process 21, as parameters used for calculating acceleration energy, deceleration energy, and potential deceleration energy, which are electric control selection indexes, Table 1 obtained from the result of the transient stability calculation simulation process 1 and FIG. Active power P0 of the target generator immediately before the occurrence of the accident, internal phase difference angle δ0, active power Pf1 immediately after the occurrence of the accident, active power Pf2 immediately before the removal of the accident, active power Pc immediately after the removal of the accident, angular velocity deviation Δωc, internal phase difference angle δc, the active power Ps immediately after the control, the angular velocity deviation Δωs, and the internal phase difference angle δs are extracted.

  In the P-δ curve calculation process 22, using the parameters extracted in the simulation result extraction process 21, the equivalent reactance X0 between the reference power supply and the target generator before the occurrence of the accident and the equivalent reactance X0 between the reference power supply and the target generator after the removal of the accident are used. The equivalent reactance Xc and the equivalent reactance Xs between the reference power supply and the target generator after power control are obtained as follows.

here,
EG: Internal voltage of target generator (pu)
E: Reference power supply voltage (pu)
And these are assumed values.

Using the results, a vertex P0max of the P-δ curve before the occurrence of the accident, a vertex Pcmax of the P-δ curve after the elimination of the accident, and a vertex Psmax of the P-δ curve after the electric control are calculated by the following equations.

  In the power control selection index calculation process 23, the magnitude relationship between the active power P0 before the accident elimination and the active power Pc immediately after the elimination of the accident, the magnitude of Ps immediately after the electrification, and the magnitude relation of P0 and Pcmax, and P0 and Psmax are respectively determined. And the following six sections, and for each section, the acceleration energy Jaf, the deceleration energy Jdc, Jds, and the potential deceleration energy Jd0 of the target generator are calculated.

Jaf: Acceleration energy of the target generator after an accident (pu)
Jd0: Potential deceleration energy (pu) of the target generator before the accident occurred (initial state)
Jdc: Deceleration energy of the target generator after accident removal (pu)
Jds: Deceleration energy of the target generator after electric control (pu)

(1) Pcmax ≦ P0 and Psmax ≦ P0 (Psmax ≧ Pcmax) (2) Pcmax ≦ P0 and Psmax> P0 (Psmax ≧ Pcmax) and Ps ≦ P0 (3) Pcmax ≦ P0 and Psmax> P0 ( Psmax ≧ Pcmax) and Ps> P0 (4) Pcmax> P0, Pc ≦ P0 and Ps ≦ P0 (Ps ≧ Pc) (5) Pcmax> P0, Pc ≦ P0 and Ps> P0 (Ps ≧ Pc) (6) Pcmax> P0 and Pc> P0 (Ps ≧ Pc)

Hereinafter, a method of calculating acceleration energy, deceleration energy, or potential deceleration energy will be described for each of the categories (1) to (6).
(1) The case where Pcmax ≦ P0 and Psmax ≦ P0 (Psmax ≧ Pcmax) will be described with reference to FIG.
In this state, since no deceleration energy is obtained before and after the electric control, the deceleration energy Jds after the removal of the accident becomes zero. Therefore, the potential deceleration energy Jd0 is used.

(A) Acceleration energy Jaf

(B) Deceleration energy Jds

(C) Potential deceleration energy Jd0

(2) A case where Pcmax ≦ P0 and Psmax> P0 (Psmax ≧ Pcmax) and Ps ≦ P0 will be described with reference to FIG.
In this state, the acceleration energy is between the occurrence of the accident and immediately before the electric control and immediately before the generator output after the electric control exceeds P0, and thereafter the deceleration energy is obtained.

(A) Acceleration energy Jaf

(B) Deceleration energy Jds

(3) A case where Pcmax ≦ P0 and Psmax> P0 (Psmax ≧ Pcmax) and Ps> P0 will be described with reference to FIG.
In this state, the acceleration energy is generated during the period from the occurrence of the accident to immediately before the electric control, and the deceleration energy is obtained after the electric control.

(A) Acceleration energy Jaf

(B) Deceleration energy Jds

(4) The case where Pcmax> P0, Pc ≦ P0 and Ps ≦ P0 (Ps ≧ Pc) will be described with reference to FIG.
In this state, the acceleration energy is between the occurrence of the accident and immediately before the electric control and immediately before the generator output after the electric control exceeds P0, and thereafter the deceleration energy is obtained.

(A) Acceleration energy Jaf

(B) Deceleration energy Jds

(5) A case where Pcmax> P0, Pc ≦ P0 and Ps> P0 (Ps ≧ Pc) will be described with reference to FIG.
In this state, until just before the generator output after between the accident removed from the accident immediately before the fault is cleared exceeds P ₀ is the acceleration energy, the deceleration energy obtained thereafter.

(A) Acceleration energy Jaf

(B) Deceleration energy Jds

(6) The case where Pcmax> P0 and Pc> P0 (Ps ≧ Pc) will be described with reference to FIG.
In this state, acceleration energy is generated from the occurrence of the accident to immediately before the accident is eliminated, and deceleration energy is obtained immediately after the accident is eliminated.

(A) Acceleration energy Jaf

(B) Deceleration energy Jds

[1-2-3. Electric machine selection output processing]
As shown in FIG. 4, in the electrical machine selection process 3, the following multiple processes are sequentially performed.

  In the electric power control target classification process 31, the generators having Jds = 0 and having no deceleration energy Jds after the accident, which may be unstable in transient stability, are grouped. When there is a generator with the deceleration energy Jds = 0 (Yes in the process 31), the electronic control unit executes the electrical machine selection process 34 for selecting an electrical electrical appliance from the generator.

  In the electrical machine selection processing 34, when the electrical machine can be selected in consideration of the restrictive condition of the electrical machine selection, the generator with the smallest electrical control selection index Jd0-Jaf is selected in the group. In the electrical machine selection determination processing 36, it is determined whether or not the electrical equipment has been selected in the electrical machine selection processing 34. If the electrical machine cannot be selected due to the constraint condition (No in process 36), the electrical control target classification process 32 is executed to select an electrical electrical machine from the remaining generators.

  When there is no generator with deceleration energy Jds = 0 in the electric power control target classification processing 31 (No in processing 31), or when no electric generator can be selected from the generator group with deceleration energy Jds = 0 ( (No in process 36) Next, generators whose deceleration energy after accident is Jds-Jaf <0, which may be unstable in system transient stability, are smaller than acceleration energy, are classified into groups in the power control target classification process 32. When there is a generator satisfying Jds-Jaf <0 (Yes in process 32), the controller 35 executes a machine selection process 35 for selecting a machine from the generator.

  In the electrical machine selection processing 35, in consideration of the restriction condition of electrical machine selection, when an electrical machine can be selected, a generator with the smallest electrical control selection index Jd0-Jaf is selected in the group. In the electrical machine selection determination processing 37, it is determined whether or not the electrical equipment has been selected in the electrical machine selection processing 35. If the electrical equipment cannot be selected due to the constraint condition (No in the processing 37), the remaining power generation is performed. In order to select a control device from the devices, a control device selection process 33 is executed.

  When there is no generator with Jds-Jaf <0 in the electric power control target classification process 32 (No in process 32), or when no electric generator can be selected from the generator group with Jds-Jaf <0 ( In the process 37 (No), the generator selection process 33 selects a generator having the smallest power selection index Jds-Jaf from the remaining generators satisfying Jds-Jaf ≧ 0.

[1-3. effect]
According to the present embodiment, as shown in process 31, when deceleration energy is not obtained, potential deceleration energy is used as a power control selection index, and when deceleration energy is obtained, acceleration energy and deceleration energy are used. By using the power control selection index using the difference between the two, it is possible to preferentially select a generator that is a main cause of the deterioration of the transient stability of the system without depending on the timing at which the generator accelerates. As a result, when the transient stability of the system can be maintained only by the generator that accelerates relatively slowly, the required power control amount decreases as compared with the conventionally used acceleration index.

  In the present embodiment, the generators are divided into groups based on the acceleration energy and the deceleration energy, and the electrical control can be selected by comparing the electrical control selection index within the group. The burden of setting work is reduced.

[2. Second Embodiment]
The second embodiment is a program for causing a computer to realize each process constituting the first embodiment. The second embodiment also includes an electronic medium on which such a program and data necessary for executing the program are recorded, such as a magnetic tape, a magnetic disk, an optical disk, a magneto-optical disk, and a flash memory.

[3. Other Embodiments]
The present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements in an implementation stage without departing from the scope of the invention. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the above embodiments. For example, some components may be deleted from all the components shown in the embodiment. Further, components of different embodiments may be appropriately combined.

P0: Active power of the target generator immediately before the accident occurred (pu)
Pf1: Active power of the target generator immediately after the accident (pu)
Pf2: Active power (pu) of the target generator immediately before the accident was removed
Pc: Active power (pu) immediately after the target generator was removed from the accident
Ps: Active power of target generator immediately after power control (pu)
Δωc: angular velocity deviation (%) of the target generator immediately after the accident was removed
Δωs: angular velocity deviation (%) of the target generator immediately after power control
δ0: Initial value of the internal phase difference angle of the target generator (rad)
δc: Internal phase difference angle (rad) of the target generator immediately after the accident was removed
δs: Internal phase difference angle (rad) immediately after power control of the target generator
EG: Internal voltage of target generator (pu)
E: Reference power supply voltage (pu)
Jaf: Acceleration energy of the target generator after the accident (pu)
Jd0: Potential deceleration energy (pu) of the target generator before the accident occurred (initial state)
Jdc: Potential deceleration energy of the target generator after the accident was eliminated (pu)
Jds: Potential deceleration energy of the target generator after electric control (pu)

Claims (6)

A method for selecting a generator suitable for power supply restriction from among a plurality of generators connected to a grid and disconnecting the grid from the grid,
For each of the plurality of generators,
(a) a process of calculating acceleration energy for increasing the rotation speed immediately after the occurrence of an accident;
(b) a process of calculating deceleration energy for reducing the rotation speed of the generator after the removal of the accident or after electric control;
(c) calculating a potential deceleration energy that can reduce the increase in the rotational speed with respect to the increase in the rotational speed of the generator before the accident occurs;
Run
Using the election control index based on the acceleration energy, deceleration energy and potential deceleration energy obtained in each of the calculation processes,
If the deceleration energy cannot be calculated, or if the deceleration energy can be calculated and the deceleration energy is smaller than the acceleration energy, select a control device based on the difference between the potential deceleration energy and the acceleration energy,
A method for selecting an electronic control unit, comprising: when deceleration energy can be calculated, and when the deceleration energy is equal to or higher than the acceleration energy, selecting the electronic control unit based on a difference between the deceleration energy and the acceleration energy. The process of calculating the potential deceleration energy includes:
And vertex P0max of power phase angle curve before the accident, using the internal phase angle δc after active power P0 and internal phase angle δ0 and fault removal before the accident, to claim 1 for calculating a potential deceleration energy Electric control selection method described. The acceleration energy calculation process, the deceleration energy calculation process and the potential deceleration energy calculation process,
A vertex P0max of a P- δ curve before the accident of the target generator calculated from the active power P0 before the accident and the internal phase difference angle δ0,
A vertex Pcmax of the P- δ curve of the target generator after the accident has been removed, calculated from the active power Pc after the accident has been eliminated and the internal phase difference angle δc;
A vertex Psmax of the P- δ curve of the target generator immediately after the power calculated from the active power Ps immediately after the power control and the internal phase difference angle δs,
Active power P0 before the occurrence of the accident, active power Pf1 immediately after the occurrence of the accident, active power Pf2 immediately before the elimination of the accident, and active power Ps immediately after the power control,
Internal phase difference angle δ0, internal phase difference angle δc after accident removal, internal phase difference angle δs immediately after electrical control,
3. The method for selecting an electrical machine according to claim 1, wherein the acceleration energy, the deceleration energy, and the potential deceleration energy are calculated by using the following.   The generator according to any one of claims 1 to 3, wherein, in the process of selecting the electrical control unit, the generators to be electronically controlled are grouped according to their acceleration energy and deceleration energy, and the electrical control unit is selected within the group. Electric control selection method described. A power generator selection program for selecting a generator suitable for power supply restriction from a plurality of generators connected to the grid and disconnecting the generator from the grid,
On the computer,
(a) a process of calculating acceleration energy for increasing the rotation speed immediately after the occurrence of an accident;
(b) a process of calculating deceleration energy for reducing the rotation speed of the generator after the removal of the accident or after electric control;
(c) calculating a potential deceleration energy that can reduce the increase in the rotation speed with respect to the increase in the rotation speed of the generator before the accident occurs;
(d) The acceleration energy obtained in each of the calculation processes, the deceleration energy and a potential deceleration energy are used, and when the deceleration energy cannot be calculated, based on the difference between the potential deceleration energy and the acceleration energy. If a deceleration energy can be calculated by selecting a control device, a process of selecting a control device based on a difference between the deceleration energy and the acceleration energy;
Control program to execute   A recording medium on which the computer according to claim 5 is recorded in a computer-readable manner.

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