CN108832620B - Method and system for evaluating effect of emergency control strategy based on deviation area - Google Patents
Method and system for evaluating effect of emergency control strategy based on deviation area Download PDFInfo
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
- H02J3/46—Controlling of the sharing of output between the generators, converters, or transformers
- H02J3/48—Controlling the sharing of the in-phase component
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J2203/00—Indexing scheme relating to details of circuit arrangements for AC mains or AC distribution networks
- H02J2203/20—Simulating, e g planning, reliability check, modelling or computer assisted design [CAD]
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/001—Methods to deal with contingencies, e.g. abnormalities, faults or failures
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Abstract
The invention provides a method and a system for evaluating the effect of an emergency control strategy based on a deviation area, wherein the method comprises the following steps: when the power system breaks down, calling a fault emergency control strategy table according to fault scene information, and determining an online matching emergency control strategy and a simulation equivalent power angle track P fz (δ fz ) And the expected remaining reduction area S xn (ii) a Calculating an actual equivalent power angle delta according to the actual power angle and rotating speed deviation of the generator at each moment after the power system fault occurs sj And the transient deviation area S pc (δ dj ) (ii) a According to S pc (δ dj ) And a comparison of S pc (δ dj ) Absolute value of and S xn Determines the effect of the emergency control strategy; and determining the running state of the power system, and determining whether to finish the evaluation according to the effect of the emergency control strategy and the running state of the system. The method can evaluate the prevention and control effect of the emergency control strategy of the power system in real time, discover the fault scene of invalid strategy as soon as possible, and provide precious decision time for adopting additional control or active disconnection.
Description
Technical Field
The present invention relates to the field of power control, and more particularly, to a method and system for evaluating the effect of an emergency control strategy based on a deviation area.
Background
In recent years, with the continuous expansion of the scale of the power system and the access of a large amount of new equipment, the characteristics of the power grid become more complex, and the safe and stable operation of the power grid faces more serious challenges. Because the power grid fault is difficult to avoid, the high-efficiency and reliable emergency control of the power system is an important guarantee for the safe and stable operation of the power grid. However, long-term operation practice of the power system shows that no matter how the emergency control strategy is perfect, the implemented emergency control strategy can hardly achieve the expected effect due to the superposition of some unexpected factors which are unpredictable in advance.
If the prevention and control effect of the emergency control strategy can be evaluated in real time, and the fault scene of the invalid strategy can be found as soon as possible, precious decision time can be provided for additional control or active disconnection.
The emergency control scheme of the power system can be divided into 3 types of 'off-line decision, real-time matching', 'on-line decision, real-time matching' and 'real-time decision and real-time matching'. The offline decision generally refers to making a decision table by performing a large amount of simulation on the expected accident in the day ahead or earlier; the on-line decision is to generate a decision table at an ultra-short period, for example, a policy table is generated by rolling every 15 min; the real-time decision is to directly calculate the control strategy according to the actual condition of the system without generating a decision table. At present, offline decision is taken as the most mature control mode and still occupies the dominant position in practical application, online decision modes are already applied in partial power grids, and real-time decision is only stopped in a research stage. Therefore, the invention mainly aims at evaluating the prevention and control effects of the off-line decision mode and the on-line decision mode.
In the process of making and implementing the existing offline and online emergency control strategies, two kinds of deviations are easily introduced in the stages of decision making and matching: one is model deviation, whether a strategy table is established offline by depending on experience or generated by online rolling depends on a power grid simulation model, and deviation generally exists between the simulation model and an actual system; the other is scenario deviation, because the "real-time matching" is realized by comparing the measured values of voltage, current, power, etc. with the simulation result, the matching predicted fault scenario may deviate from the actual fault scenario.
The existence of the model deviation and the scene deviation causes that a simulation track in an expected fault scene is not coincident with an actual multi-machine disturbed track, namely, a track deviation exists, when the track deviation is large, the emergency control strategy can possibly fail to achieve the expected effect, and the preset control strategy is ineffective in an actual scene, so that how to timely and effectively evaluate the effectiveness of the emergency control strategy of the power system becomes a problem to be solved urgently in the field of power control.
Disclosure of Invention
In order to solve the technical problem that the emergency control strategy cannot achieve the expected effect due to the track deviation between the simulation track and the actual multi-machine disturbed track in the expected fault scene caused by the existence of model deviation and scene deviation in the process of making and implementing the existing offline and online emergency control strategies in the background art, the invention provides a method for evaluating the effect of the emergency control strategy based on the deviation area, which comprises the following steps:
and 4, determining the running state of the power system, and determining whether to finish evaluation according to the effect of the emergency control strategy and the running state of the system.
Further, determining the power system operation state, and determining whether to end the evaluation according to the effect of the emergency control strategy and the system operation state includes:
when the output evaluation result is that the strategy is effective, the power system does not reach a steady state or when the output evaluation result is that the strategy is ineffective, the power system returns to the step 2 if the power system is in a non-desynchronizing state;
and when the emergency control strategy is effective and the running state of the power system reaches a steady state, or when the emergency control strategy is ineffective and the running state of the power system is out of step, namely the out-of-step separation device acts, finishing the evaluation.
Further, before calling the emergency control strategy table according to the fault scene information, the method also comprises the step of calculating the simulation when the emergency control strategy is adopted in the expected fault sceneEquivalent power angle locus P fz (δ eq ) And the expected remaining reduction area S xn Forming a fault emergency control strategy table in which an equivalent power angle locus P is simulated fz (δ eq ) The power angle locus of the generator of the multi-machine system forms a power angle curve of a single-machine infinite system through complementary group inertia center-relative motion transformation, delta eq Is a simulated equivalent power angle under the expected fault.
Further, the simulation equivalent power angle locus P fz (δ eq ) And the expected remaining reduction area S xn The method is offline solution or online rolling solution, and is synchronously performed and synchronously stored in the generation process of the emergency control strategy table.
Further, the simulation equivalent power angle locus P fz (δ eq ) And the actual equivalent power angle locus P sj (δ sj ) Equating using a complementary group inertia center-to-relative motion transform, the method comprising:
for an electric power system with n generators, grouping the n generators by adopting an extended equal-area method, wherein an operation disturbed unit belongs to a K group, and the rest units belong to a W group, simplifying the system of the n generators by adopting complementary group inertia center-relative motion transformation and equating the system to a single-machine infinite system, wherein the motion equation is as follows:
in the formula, M eq 、ω eq And delta eq Equivalent inertia, equivalent rotation speed deviation and equivalent power angle, P, of a single-machine infinite system m,eq And P e,eq Equivalent mechanical power and electromagnetic power respectively;
let M i 、ω i And delta i Respectively, the moment of inertia, the rotational speed deviation and the work angle, P, of the ith generator mi And P ei The mechanical power and the electromagnetic power of the ith generator are respectively obtained, and the method for solving the parameters in the formula is as follows:
P m,eq ＝(M W P mK -M K P mW )/M T ；P e,eq ＝(M W P eK -M K P eW )/M T ；
in the formula, subscripts W and K respectively represent a W machine group and a K machine group, and subscript T represents all the generator sets.
Further, the equivalent electromagnetic power P is simulated e-fz (δ eq ＝δ sj ) And the actual equivalent electromagnetic power P e-sj (δ sj ) Calculating the actual equivalent power angle from delta 0 Swing to delta sj Time of transient deviation area S pc (δ sj ) The calculation formula of (2) is as follows:
further, the transient deviation area S according to the current time pc (δ sj ) Positive and negative of value of (1) and S pc (δ sj ) Absolute value of (d) and expected remaining reduction area S xn The determining the effect of the emergency control strategy comprises:
when S is pc (δ sj ) When the evaluation result is more than or equal to 0, outputting the evaluation result as effective strategy;
when S is pc (δ sj )<0 and | S pc |＞＞S xn If so, outputting the evaluation result as invalid strategy;
when P is pc (δ sj )<0 and | S pc |<S xn Then outputAnd evaluating that the strategy is effective.
Further, the electric power system reaching the steady state means that power angle difference fluctuation among the generators of the electric power system is kept in a preset interval.
According to another aspect of the invention, there is provided a system for evaluating an effect of an emergency control strategy based on a deviation area, the system comprising:
a matching unit for calling a failure emergency control strategy table according to the failure scene information when the power system fails, and determining an online matching emergency control strategy and a simulation equivalent power angle track P fz (δ eq ) And the expected remaining reduction area S xn Wherein, the equivalent power angle locus P is simulated fz (δ eq ) The power angle locus of the generator of the multi-machine system forms a power angle curve of a single-machine infinite system through complementary group inertia center-relative motion transformation, delta eq Is a simulated equivalent power angle under the expected fault, and the expected residual deceleration area S xn Is based on a simulated equivalent power angle track P obtained in an expected fault scene fz (δ eq ) After a virtual mechanical power track and a virtual electromagnetic power track are constructed, the area enclosed by the virtual electromagnetic power track and the virtual mechanical power track is obtained, the virtual mechanical power track is a curve formed by horizontally extending equivalent mechanical power at a point E, the virtual electromagnetic power track is a curve formed by sine prediction of the equivalent electromagnetic power at the point E, and the point E is the farthest point in the first swing process;
a deviation area determination unit for converting the actual generator power angle and rotation speed deviation data measured during the operation of the power system into an actual equivalent power angle locus P after the complementary group inertia center-relative motion sj (δ sj ) According to the actual equivalent power angle locus P sj (δ sj ) The actual equivalent power angle delta corresponding to the actual power angle of the generator measured at each moment after the fault occurs sj Determining the actual equivalent electromagnetic power P e-sj (δ sj ) And according to the simulated equivalent power angle trajectory P fz (δ eq ) The actual equivalent power angle delta corresponding to the actual power angle of the generator measured at each moment after the fault occurs sj Determining a simulated equivalent power angle delta eq Is equal to the actual equivalent power angle delta sj Time-corresponding simulated equivalent electromagnetic power P e-fz (δ eq ＝δ sj ) And by means of said simulated equivalent electromagnetic power P e-fz (δ eq ＝δ sj ) And the actual equivalent electromagnetic power P e-sj (δ sj ) Calculating the actual equivalent power angle from delta 0 Swing to delta sj Time transient deviation area S pc (δ sj ) Wherein the actual equivalent power angle at the time of the fault occurrence is delta 0 ；
A control effect determination unit for determining the transient deviation area delta according to the current time pc (δ sj ) Positive and negative values of (1) and comparison S pc (δ sj ) Absolute value of (d) and expected remaining reduction area S xn Determining the effect of the emergency control strategy, wherein the effect comprises strategy effectiveness and strategy ineffectiveness;
and the operation state determining unit is used for determining the operation state of the power system and determining whether to finish the evaluation according to the effect of the emergency control strategy and the operation state of the system.
Further, the operation state determination unit determining the operation state of the power system, and determining whether to end the evaluation according to the effect of the emergency control strategy and the system operation state includes:
when the emergency control strategy is effective and the running state of the power system does not reach a steady state, or when the emergency control strategy is ineffective and the running state of the power system is not out of step, returning to the deviation area determining unit;
and when the emergency control strategy is effective and the running state of the power system reaches a steady state, or when the emergency control strategy is ineffective and the running state of the power system is out of step, namely the out-of-step disconnecting device acts, finishing the evaluation.
Further, the system also comprises a control strategy establishing unit, which is used for calculating the simulated equivalent power-angle locus P when the emergency control strategy is adopted in the expected fault scene fz (δ eq ) And the expected remaining reduction area S xn Forming a fault emergency control strategy table in which equivalent power angle trajectories are simulatedP fz (δ eq ) The power angle locus of the generator of the multi-machine system forms a power angle curve of a single-machine infinite system through complementary group inertia center-relative motion transformation, delta eq Is a simulated equivalent power angle under the expected fault.
Further, the simulated equivalent power angle trajectory P generated in the control strategy establishing unit fz (δ eq ) And the expected remaining reduction area S xn The method is offline acquisition or online rolling acquisition, and is synchronously performed and synchronously stored in the generation process of the fault emergency control strategy table.
Further, the simulation equivalent power angle locus P of the control strategy establishing unit fz (δ eq ) And the actual equivalent power angle locus P sj (δ sj ) Equating using complementary cluster inertia center-relative motion transformations includes:
for an electric power system with n generators, grouping the n generators by adopting an extended equal-area method, wherein an operation disturbed unit belongs to a K group, and the rest units belong to a W group, simplifying the system of the n generators by adopting complementary group inertia center-relative motion transformation and equating the system to a single-machine infinite system, wherein the motion equation is as follows:
in the formula, M eq 、ω eq And delta eq Equivalent inertia, equivalent rotation speed deviation and equivalent power angle, P, of a single-machine infinite system m,eq And P e,eq Equivalent mechanical power and electromagnetic power respectively;
let M i 、ω i And delta i Respectively, the moment of inertia, the rotational speed deviation and the work angle, P, of the ith generator mi And P ei The mechanical power and the electromagnetic power of the ith generator are respectively obtained, and the method for solving the parameters in the formula is as follows:
P m,eq ＝(M W P mK -M K P mW )/M T ；P e,eq ＝(M W P eK -M K P eW )/M T ；
in the formula, subscripts W and K respectively represent a W cluster and a K cluster, and subscript T represents all the generator sets.
Further, the deviation area determination unit determines the equivalent electromagnetic power P through the simulation e-fz (δ eq ＝δ sj ) And the actual equivalent electromagnetic power P e-sj (δ sj ) Calculating the actual equivalent power angle from delta 0 Swing to delta sj Time of transient deviation area S pc (δ sj ) The calculation formula of (2) is as follows:
further, the control effect determination unit determines the transient deviation area S according to the current time pc (δ sj ) Positive or negative of value (S) and S pc (δ sj ) Is compared with the expected remaining reduction area S xn The determining of the effect of the emergency control strategy comprises:
when S is pc (δ sj ) When the evaluation result is more than or equal to 0, outputting the evaluation result as effective strategy;
when S is pc (δ sj )<0 and | S pc |＞＞S xn If so, outputting the evaluation result as invalid strategy;
when S is pc (δ sj )<0 and | S pc |<S xn And if so, outputting the evaluation result as that the strategy is effective.
Further, the operation state determination unit determines that the power system reaches the steady state, which means that power angle difference fluctuation between the generators of the power system is kept in a preset interval.
The method and the system for evaluating the effect of the emergency control strategy based on the transient deviation area provided by the invention form the equivalent single-machine infinite system power angle track after the multi-machine system power angle track under the expected fault scene and the actual measurement power angle track provided by the wide-area measurement system are respectively subjected to complementary group inertia center-relative motion transformation, then the track deviation is integrated to obtain the transient deviation area, and the control effect of the emergency control strategy is evaluated in real time according to the positive and negative of the transient deviation area value and the size relation between the absolute value of the transient deviation area value and the expected residual deceleration area.
Drawings
Exemplary embodiments of the invention may be more completely understood in consideration of the following drawings:
FIG. 1 is a flow chart of a method of evaluating the effectiveness of an emergency control strategy based on a deviation area in accordance with a preferred embodiment of the present invention;
FIG. 2 is a simulated equivalent power angle trajectory diagram for evaluating the effect of an emergency control strategy based on the area of deviation in accordance with a preferred embodiment of the present invention;
fig. 3 is a schematic diagram showing a comparison between a simulated equivalent power angle trajectory diagram and an actual equivalent power angle trajectory diagram for evaluating the effect of the emergency control strategy based on the area of deviation according to the preferred embodiment of the present invention;
FIG. 4 is a block diagram of a system for evaluating the effectiveness of an emergency control strategy based on a deviation area in accordance with a preferred embodiment of the present invention;
fig. 5 is a grid structure diagram of a standard calculation example adopted by the method for evaluating the effect of the emergency control strategy based on the deviation area according to another preferred embodiment of the present invention;
FIG. 6 is a plot of the transient deviation area trace for another preferred embodiment of the present invention;
fig. 7 is a graph of the power angle of a generator according to another preferred embodiment of the present invention.
Detailed Description
The exemplary embodiments of the present invention will now be described with reference to the accompanying drawings, however, the present invention may be embodied in many different forms and is not limited to the embodiments described herein, which are provided for complete and complete disclosure of the present invention and to fully convey the scope of the present invention to those skilled in the art. The terminology used in the exemplary embodiments illustrated in the accompanying drawings is not intended to be limiting of the invention. In the drawings, the same units/elements are denoted by the same reference numerals.
Unless otherwise defined, terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In addition, it will be understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their context in the context of the relevant art and will not be interpreted in an idealized or overly formal sense.
Example one
Fig. 1 is a flow chart of a method of evaluating the effect of an emergency control strategy based on a deviation area according to a preferred embodiment of the present invention. As shown in fig. 1, the method 100 for evaluating the effect of an emergency control strategy based on a deviation area according to the present invention begins at step 101.
In step 101, a simulated equivalent power angle trajectory P is calculated when an emergency control strategy is adopted in an expected fault scene fz (δ eq ) And the expected remaining reduction area S xn Forming a fault emergency control strategy table in which an equivalent power angle locus P is simulated fz (δ eq ) The power angle locus of the generator of the multi-machine system forms a power angle curve of a single-machine infinite system through complementary group inertia center-relative motion transformation, delta eq Is toAnd (4) simulating an equivalent power angle under the condition of fault.
Preferably, the simulated equivalent power angle trajectory P fz (δ eq ) And the expected remaining reduction area S xn The method is offline solution or online rolling solution, and is synchronously performed and synchronously stored in the generation process of the emergency control strategy table.
In step 102, when the power system fails, a failure emergency control strategy table is called according to the failure scene information, and an online matching emergency control strategy and a simulation equivalent power angle track P are determined fz (δ eq ) And the expected remaining reduction area S xn Wherein, an equivalent power angle locus P is simulated fz (δ eq ) The power angle locus of the generator of the multi-machine system forms a power angle curve of a single-machine infinite system through complementary group inertia center-relative motion transformation, delta eq Is a simulated equivalent power angle under the expected fault, and the expected residual deceleration area S xn Is based on a simulated equivalent power angle track P obtained in an expected fault scene fz (δ eq ) After a virtual mechanical power track and a virtual electromagnetic power track are constructed, the area enclosed by the virtual electromagnetic power track and the virtual mechanical power track is obtained, the virtual mechanical power track is a curve formed by horizontally extending equivalent mechanical power at a point E, the virtual electromagnetic power track is a curve formed by sine prediction of the equivalent electromagnetic power at the point E, and the point E is the farthest point in the initial swing process.
Fig. 2 is a diagram of a simulated equivalent power angle trajectory in accordance with a preferred embodiment of the present invention. As shown in FIG. 2, P B Is a simulated equivalent power angle track, the point E is the farthest point in the initial pendulum process, and the expected residual deceleration area S xn Is based on the simulation equivalent power angle locus P B After a virtual mechanical power track and a virtual electromagnetic power track are constructed, the area enclosed by the virtual electromagnetic power track and the virtual mechanical power track is obtained, wherein the virtual mechanical power track is a curve formed by horizontally extending equivalent mechanical power at a point E, and the virtual electromagnetic power track is equivalent electromagnetic power, namely a simulated equivalent power angle track P B The curve formed by sinusoidal prediction at point E. When curve P B When swinging back after reaching the farthest point EThe present invention is described as being able to effectively prevent system instability after an emergency control strategy is implemented in an expected failure scenario.
In step 103, the actual equivalent power angle trajectory P is obtained by transforming the actual power angle and rotation speed deviation data of the generator measured during the operation of the power system through the complementary group inertia center-relative motion sj (δ sj ) According to the actual equivalent power angle locus P sj (δ sj ) The actual equivalent power angle delta corresponding to the actual power angle of the generator measured at each moment after the fault occurs sj Determining the actual equivalent electromagnetic power P e-sj (δ sj ) And according to the simulated equivalent power angle trajectory P fz (δ eq ) The actual equivalent power angle delta corresponding to the actual power angle of the generator measured at each moment after the fault occurs sj Determining a simulated equivalent power angle delta eq Is equal to the actual equivalent power angle delta sj Time-corresponding simulated equivalent electromagnetic power P e-fz (δ eq ＝δ sj ) And by means of said simulated equivalent electromagnetic power P e-fz (δ eq ＝δ sj ) And the actual equivalent electromagnetic power P e-sj (δ sj ) Calculating the actual equivalent power angle from delta 0 Swing to delta sj Time of transient deviation area S pc (δ sj ) Wherein the actual equivalent power angle at the time of the fault occurrence is delta 0 。
Preferably, the simulated equivalent power angle trajectory P fz (δ eq ) And the actual equivalent power angle locus P sj (δ sj ) Equating using a complementary group inertia center-to-relative motion transform, the method comprising:
for an electric power system with n generators, grouping the n generators by adopting an extended equal-area method, wherein an operation disturbed unit belongs to a K group, and the rest units belong to a W group, simplifying the system of the n generators by adopting complementary group inertia center-relative motion transformation and equating the system to a single-machine infinite system, wherein the motion equation is as follows:
in the formula, M eq 、ω eq And delta eq Equivalent inertia, equivalent rotation speed deviation and equivalent power angle, P, of a single-machine infinite system m,eq And P e,eq Equivalent mechanical power and electromagnetic power respectively;
let M i 、ω i And delta i Respectively, the moment of inertia, the rotational speed deviation and the work angle, P, of the ith generator mi And P ei The mechanical power and the electromagnetic power of the ith generator are respectively, and the method for solving the parameters in the formula is as follows:
P m,eq ＝(M W P mK -M K P mW )/M T ；P e,eq ＝(M W P eK -M K P eW )/M T ；
in the formula, subscripts W and K respectively represent a W cluster and a K cluster, and subscript T represents all the generator sets.
Preferably, the equivalent electromagnetic power P is simulated by the simulation e-fz (δ eq ＝δ sj ) And the actual equivalent electromagnetic power P e-sj (δ sj ) Calculating the actual equivalent power angle from delta 0 Swing to delta sj Time of transient deviation area S pc (δ sj ) The calculation formula of (c) is:
in step 104, the area is determined according to the transient deviation when the fault occursS pc (δ sj ) Positive and negative values of (1) and comparison S pc (δ sj ) Absolute value of (d) and expected remaining reduction area S xn Determines the effect of the emergency control strategy, wherein the effect includes a strategy being valid and a strategy being invalid.
Preferably, the transient deviation area S according to the current time pc (δ sj ) Positive and negative of value of (1) and S pc (δ sj ) Absolute value of (d) and expected remaining reduction area S xn The determining the effect of the emergency control strategy comprises:
when S is pc (δ sj ) When the evaluation result is more than or equal to 0, outputting the evaluation result as effective strategy;
when S is pc (δ sj )<0 and | S pc |＞＞S xn If so, outputting the evaluation result as invalid strategy;
when S is pc (δ sj )<0 and | S pc |<S xn And if so, outputting the evaluation result as that the strategy is effective.
Fig. 3 is a schematic diagram of a comparison between a simulated equivalent power angle trajectory diagram and an actual equivalent power angle trajectory diagram for evaluating the effect of the emergency control strategy based on the deviation area according to the preferred embodiment of the present invention. In the actual operation process, the actual equivalent power angle trajectory and the simulated equivalent power angle trajectory may have deviation under the influence of operation conditions, model deviation and the like. As shown in fig. 3, curve P B For simulating an equivalent power angle trajectory, curve P A And P C The actual equivalent power angle trajectories under two possible scenarios. As can be seen from FIG. 3, if the actual equivalent power-angle trajectory runs at P A Above, then relative to the simulated equivalent power angle trajectory P B The actual residual deceleration area is increased, and if the actual equivalent power angle track runs at P C Above, then relative to the simulated equivalent power angle trajectory P B In an extreme case, when the actual remaining deceleration area is smaller than 0, the actual equivalent power angle trajectory will pass through a Dynamic Saddle Point (DSP), and the system is unstable, and at this time, it can be considered that the emergency control measure is invalid, and the system instability cannot be prevented. Therefore, the basic principle of the method is as follows:
if S pc (δ sj ) And the actual running state is superior to the expected simulation result if the actual residual deceleration area of the system is larger than the expected value. Therefore, the emergency control strategy in the scene is considered to achieve the expected control effect, namely the strategy is effective.
If S pc (δ sj )<0, which indicates that the actual remaining deceleration area of the system is smaller than the expected value, the actual running state is worse than the expected simulation result, and whether the system is unstable at this time depends on the deterioration degree, namely:
if S is in the process of operation pc (δ sj )<0 and | S pc |<S xn Although the accumulated effect of the trajectory deviation during the power angle swing deteriorates the transient stability of the system, the deterioration degree is light and is not enough to offset the expected residual deceleration area S xn The emergency control strategy is still effective.
If in the process of operation V pc (δ sj )<0 and | S pc |＞＞S xn The cumulative effect of the deviations in trajectory is illustrated as severely degrading the transient stability of the system, and to the extent that the expected residual deceleration area S has been offset xn The emergency control strategy will fail.
In step 105, the power system operating state is determined and it is determined whether to proceed with the evaluation according to the effect of the emergency control strategy and the operating state of the power system, i.e.:
when the emergency control strategy is valid and the operation state of the power system is not reached to the steady state, or when the emergency control strategy is invalid and the operation state of the power system is not out of step, the final operation state of the system cannot be determined, so the evaluation is continued and the step 103 is skipped.
And when the emergency control strategy is effective and the running state of the power system reaches a steady state, or when the emergency control strategy is ineffective and the running state of the power system is out of step, namely the out-of-step separation device acts, finishing the evaluation.
Preferably, the electric power system reaching the steady state means that power angle difference fluctuation among the generators of the electric power system is kept in a preset interval. Typically, the predetermined interval is from-5 ° to 5 °.
Fig. 4 is a block diagram of a system for evaluating the effect of an emergency control strategy based on a deviation area according to a preferred embodiment of the present invention. As shown in fig. 4, the system 400 for evaluating the effect of the emergency control strategy based on the deviation area according to the preferred embodiment of the present invention includes:
a control strategy establishing unit 401 for calculating a simulated equivalent power angle trajectory P when an emergency control strategy is adopted in an expected fault scene fz (δ eq ) And the expected remaining reduction area S xn Forming a fault emergency control strategy table in which an equivalent power angle locus P is simulated fz (δ eq ) The power angle locus of the generator of the multi-machine system forms a power angle curve of a single-machine infinite system through complementary group inertia center-relative motion transformation, delta eq Is a simulated equivalent power angle under the expected fault.
Preferably, the simulated equivalent power-angle trajectory P generated in the control strategy establishing unit 301 fz (δ eq ) Expected remaining reduction area S xn The method is offline solution or online rolling solution, and is synchronously performed and synchronously stored in the generation process of the emergency control strategy table.
A matching unit 302, configured to invoke a failure emergency control policy table according to failure scenario information when a power system fails, and determine an online matching emergency control policy, a simulated equivalent power angle trajectory P fz (δ eq ) Expected transient kinetic energy V fz Trajectory and expected residual deceleration area S xn Wherein an equivalent power angle locus P is simulated fz (δ eq ) The power angle locus of the generator of the multi-machine system is transformed into a power angle curve, delta, of a single-machine infinite system through complementary group inertia center-relative motion eq Is a simulated equivalent power angle under the expected fault, and the expected residual deceleration area S xn Is a transient stability margin under an expected failure.
Preferably, the simulated equivalent power-angle trajectory P of the control strategy establishing unit 301 fz (δ eq ) And the actual equivalent power angle locus P sj (δ sj ) Equating using a complementary cluster inertia center-relative motion transform includes:
for an electric power system with n generators, grouping the n generators by adopting an extended equal-area method, wherein an operation disturbed unit belongs to a K group, and the rest units belong to a W group, simplifying the system of the n generators by adopting complementary group inertia center-relative motion transformation and equating the system to a single-machine infinite system, wherein the motion equation is as follows:
in the formula, M eq 、ω eq And delta eq Equivalent inertia, equivalent rotation speed deviation and equivalent power angle, P, of a single-machine infinite system m,eq And P e,eq Equivalent mechanical power and electromagnetic power respectively;
let M i 、ω i And delta i Respectively, the moment of inertia, the rotational speed deviation and the work angle, P, of the ith generator mi And P ei The mechanical power and the electromagnetic power of the ith generator are respectively obtained, and the method for solving the parameters in the formula is as follows:
P m,eq ＝(M W P mK -M K P mW )/M T ；P e,eq ＝(M W P eK -M K P eW )/M T ；
in the formula, subscripts W and K respectively represent a W cluster and a K cluster, and subscript T represents all the generator sets.
Deviation area determination unit 303, the system is used for converting actual power angle and rotation speed deviation data of the generator measured during the operation of the power system through the complementary group inertia center-relative motion to obtain an actual equivalent power angle track S sj (δ sj ) According to the actual equivalent power angle locus P sj (δ sj ) The actual equivalent power angle delta corresponding to the actual power angle of the generator measured at each moment after the fault occurs sj Determining the actual equivalent electromagnetic power P e-sj (δ sj ) And according to the simulated equivalent power angle trajectory P fz (δ eq ) The actual equivalent power angle delta corresponding to the actual power angle of the generator measured at each moment after the fault occurs sj Determining a simulated equivalent power angle delta eq Is equal to the actual equivalent power angle delta sj Time-corresponding simulated equivalent electromagnetic power P e-fz (δ eq ＝δ sj ) And by the simulation equivalent electromagnetic power P e-fz (δ eq ＝δ sj ) And the actual equivalent electromagnetic power P e-sj (δ sj ) Calculating the actual equivalent power angle from delta 0 Swing to delta sj Time transient deviation area S pc (δ sj ) Wherein the actual equivalent power angle at the time of the fault occurrence is delta 0 。
Preferably, the deviation area determination unit determines the equivalent electromagnetic power P by the simulation e-fz (δ eq ＝δ sj ) And the actual equivalent electromagnetic power P e-Spc (δ sj ) Calculating the actual equivalent power angle from delta 0 Swing to delta sj Time of transient deviation area S pc (δ sj ) The calculation formula of (c) is:
a control effect determination unit 304 for determining the transient deviation area S according to the current time pc (δ sj ) Positive and negative values of (1) and comparison S pc (δ sj ) Absolute value of (d) and expected remaining reduction area S xn Determines the effect of the emergency control strategy, wherein the effect includes a strategy being valid and a strategy being invalid.
Preferably, the control effect determining unit determines the transient deviation area S according to the current time pc (δ sj ) Positive and negative of value of (1) and S pc (δ sj ) Absolute value of (d) and expected remaining reduction area S xn The determining the effect of the emergency control strategy comprises:
when S is pc (δ sj ) When the evaluation result is more than or equal to 0, outputting the evaluation result as effective strategy;
when S is pc (δ sj )<0 and | S pc |＞＞S xn If so, outputting the evaluation result as invalid strategy;
when S is pc (δ sj )<0 and | S pc |<S xn And if so, outputting the evaluation result as that the strategy is effective.
And an operating state determination unit 305 for determining an operating state of the power system and determining whether to end the evaluation according to the effect of the emergency control strategy and the system operating state.
Preferably, the operation state determination unit determining the operation state of the power system, and determining whether to end the evaluation according to the effect of the emergency control strategy and the system operation state includes:
when the emergency control strategy is effective and the running state of the power system does not reach a steady state, or when the emergency control strategy is ineffective and the running state of the power system is not out of step, returning to the deviation area determining unit;
and when the emergency control strategy is effective and the running state of the power system reaches a steady state, or when the emergency control strategy is ineffective and the running state of the power system is out of step, namely the out-of-step disconnection device acts, ending the evaluation.
Preferably, the operation state determination unit determines that the power system reaches the steady state, which means that power angle difference fluctuation between the generators of the power system is maintained in a preset interval. Typically, the predetermined interval is from-5 ° to 5 °.
Example two
Fig. 5 is a grid structure diagram of a standard calculation example adopted by the method for evaluating the effect of the emergency control strategy based on the deviation area according to another preferred embodiment of the present invention. As shown in fig. 5, the preferred embodiment employs an IEEE39 node system standard calculation example. Assume that the expected failure scenario is: permanent three-phase short circuit faults occur in the lines 16-17, and the faults are cleared by cutting off the lines at 0.4 s. The emergency control strategy formulated for the fault scenario is as follows: the generator G _33 is cut off with 400MW active power at 30 cycles.
Assuming that the actual duration of the fault is 23 cycles, the evaluation process of the emergency control strategy prevention and control effect by the method of the invention is as follows:
in step 1, offline converting the power angle locus of the multi-machine system in the expected fault scene through the complementary group inertia center-relative motion to form an equivalent simulation power angle locus, constructing a virtual locus and calculating the expected residual deceleration area S xn ＝0.0024pu。
In step 2, judging whether the system has a fault, if so, matching an emergency control strategy and an equivalent simulation power angle track P on line according to fault scene information fz (δ eq ) And the expected remaining reduction area S xn The matching fault scenario is assumed to be the expected fault scenario.
In step 3, the actual power angle and rotation speed deviation data of the generator provided by the measuring system are transformed into the group inertia center-relative motion to obtain the actual equivalent power angle locus P sj (δ sj ) According to the actual equivalent power angle locus P sj (δ sj ) The actual equivalent power angle delta corresponding to the actual power angle of the generator measured at each moment after the fault occurs sj Determining the actual equivalent electromagnetic power P e-sj (δ sj ) And according to the simulated equivalent power angle trajectory P fz (δ eq ) The actual equivalent power angle delta corresponding to the actual power angle of the generator measured at each moment after the fault occurs sj Determining a simulated equivalent power angle delta eq Is equal to the actual equivalent power angle delta sj Time-corresponding simulated equivalent electromagnetic power P e-fz (δ eq ＝δ sj ) And by the simulation equivalent electromagnetic power P e-fz (δ eq ＝δ sj ) And the actual equivalent electromagnetic power P e-sj (δ sj ) Calculating the actual equivalent power angle from delta 0 Swing to delta sj Time of transient deviation area S pc (δ sj ) Wherein the actual equivalent power angle at the time of the fault occurrence is delta 0 Area of transient deviation S pc (δ sj ) The calculation formula of (2) is as follows:
in step 4, when S pc (δ sj ) When the evaluation result is more than or equal to 0, outputting the evaluation result as effective strategy;
when S is pc (δ dj )<0 and | S pc |＞＞S xn If so, outputting the evaluation result as invalid strategy;
when S is pc (δ dj )<0 and | S pc |<S xn And if so, outputting the evaluation result as that the strategy is effective.
In step 5, when the output evaluation result is that the strategy is effective, the power system does not reach the steady state or when the output evaluation result is that the strategy is ineffective, the power system returns to the step 3 in the state of no desynchronization.
In step 6, when the output evaluation result is that the strategy is effective, the power system reaches a steady state, or when the output evaluation result is that the strategy is ineffective, the power system is in a step-out state, and the evaluation is finished.
Fig. 6 is a plot of the transient deviation area trace for another preferred embodiment of the present invention. The transient deviation area trace obtained by repeating the steps 3 to 6 is shown in fig. 6, and it can be seen that the emergency control strategy is judged to be invalid in 0.46 s.
Fig. 7 is a graph of the power angle of a generator according to another preferred embodiment of the present invention. As shown in fig. 7, the actual power angle traces of the generators are all displayed, and it can be seen that the relative power angle between the generators exceeds 180 degrees and continues to increase, which indicates that power angle instability of the power system finally occurs, and the evaluation result is correct.
Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to "a/an/the [ means, component, etc. ] are to be interpreted openly as referring to at least one instance of said means, component, etc., unless explicitly stated otherwise. The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless explicitly stated.
Claims (16)
1. A method for evaluating an effect of an emergency control strategy based on a deviation area, the method comprising:
step 1, calling a fault emergency control strategy table according to fault scene information when a power system fails, and determining an online matching emergency control strategy and a simulation equivalent power angle track P fz (δ eq ) And the expected remaining reduction area S xn Wherein, an equivalent power angle locus P is simulated fz (δ eq ) The power angle locus of the generator of the multi-machine system forms a power angle curve of a single-machine infinite system through complementary group inertia center-relative motion transformation, delta eq Is a simulated equivalent power angle under the expected fault, and the expected residual deceleration area S xn Is based on a simulated equivalent power angle track P obtained in an expected fault scene fz (δ eq ) After a virtual mechanical power track and a virtual electromagnetic power track are constructed, the area enclosed by the virtual electromagnetic power track and the virtual mechanical power track is obtained, the virtual mechanical power track is a curve formed by horizontally extending equivalent mechanical power at a point E, the virtual electromagnetic power track is a curve formed by sine prediction of the equivalent electromagnetic power at the point E, and the point E is the farthest point in the first swing process;
step 2, obtaining an actual equivalent power angle track P after the actual power angle and rotating speed deviation data of the generator measured during the operation of the power system are subjected to complementary group inertia center-relative motion transformation sj (δ sj ) According to the actual equivalent power angle locus P sj (δ sj ) The actual equivalent power angle delta corresponding to the actual power angle of the generator measured at each moment after the fault occurs sj Determining the actual equivalent electromagnetic power P e-sj (δ sj ) And according to the simulated equivalent power angle trajectory P fz (δ eq ) Actual equivalence corresponding to actual generator power angle measured at each moment after fault occurrenceWork angle delta sj Determining a simulated equivalent power angle delta eq Is equal to the actual equivalent power angle delta sj Time-corresponding simulated equivalent electromagnetic power P e-fz (δ eq ＝δ sj ) And by the simulation equivalent electromagnetic power P e-fz (δ eq ＝δ sj ) And the actual equivalent electromagnetic power P e-sj (δ sj ) Calculating the transient deviation area S when the actual equivalent power angle swings from delta 0 to delta sj pc (δ sj ) Wherein the actual equivalent power angle at the time of the fault occurrence is delta 0 ；
Step 3, according to the transient deviation area S when the fault occurs pc (δ sj ) Positive and negative values of (1) and comparison S pc (δ sj ) Is compared with the expected remaining reduction area S xn Determining the effect of the emergency control strategy, wherein the effect comprises strategy effectiveness and strategy ineffectiveness;
and 4, determining the running state of the power system, and determining whether to finish evaluation according to the effect of the emergency control strategy and the running state of the system.
2. The method of claim 1, wherein determining the power system operating status and determining whether to end the evaluation based on the effect of the emergency control strategy and the system operating status comprises:
when the output evaluation result is that the strategy is effective, the power system does not reach a steady state or when the output evaluation result is that the strategy is ineffective, the power system returns to the step 2 if the power system is in a non-out-of-step state;
and when the emergency control strategy is effective and the running state of the power system reaches a steady state, or when the emergency control strategy is ineffective and the running state of the power system is out of step, namely the out-of-step separating device acts, ending the evaluation.
3. The method according to claim 1 or 2, further comprising calculating a simulated equivalent power angle locus P when the emergency control strategy is adopted in the expected failure scene before invoking the failure emergency control strategy table according to the failure scene information fz (δ eq ) And expected residual subtractionArea S of velocity xn Forming a fault emergency control strategy table in which an equivalent power angle locus P is simulated fz (δ eq ) The power angle locus of the generator of the multi-machine system is transformed into a power angle curve, delta, of a single-machine infinite system through complementary group inertia center-relative motion eq Is a simulated equivalent power angle under the expected fault.
4. The method of claim 3, wherein the simulated isowork angle trajectory P is fz (δ eq ) And the expected remaining reduction area S xn The method is offline solution or online rolling solution, and is synchronously performed and synchronously stored in the generation process of the emergency control strategy table.
5. The method of claim 3, wherein the simulated isowork angle trajectory P is fz (δ eq ) And the actual equivalent power angle locus P sj (δ sj ) Equating using a complementary cluster inertia center-to-relative motion transform, the method comprising:
for an electric power system with n generators, grouping the n generators by adopting an extended equal-area method, wherein an operation disturbed unit belongs to a K group, and the rest units belong to a W group, simplifying the system of the n generators by adopting complementary group inertia center-relative motion transformation and equating the system to a single-machine infinite system, wherein the motion equation is as follows:
in the formula, M eq 、ω eq And delta eq Equivalent inertia, equivalent rotation speed deviation and equivalent power angle, P, of a single-machine infinite system m,eq And P e,eq Equivalent mechanical power and electromagnetic power respectively;
let M i 、ω i And delta i Respectively, the moment of inertia, the rotational speed deviation and the work angle, P, of the ith generator mi And P ei Mechanical power and electromagnetic power of the ith generator respectivelyThe method for solving each parameter in the method comprises the following steps:
P m,eq ＝(M W P mK -M K P mW )/M T ；P e,eq ＝(M W P eK -M K P eW )/M T ；
in the formula, subscripts W and K respectively represent a W machine group and a K machine group, and subscript T represents all the generator sets.
6. Method according to claim 5, characterized in that by means of the simulated equivalent electromagnetic power P e-fz (δ eq ＝δ sj ) And the actual equivalent electromagnetic power P e-sj (δ sj ) Calculating the actual equivalent power angle from delta 0 Swing to delta sj Time transient deviation area S pc (δ sj ) The calculation formula of (2) is as follows:
7. the method of claim 6, wherein the transient deviation area S is based on the current time instant pc (δ sj ) Positive and negative of value of (1) and S pc (δ sj ) Absolute value of (d) and expected remaining reduction area S xn The determining of the effect of the emergency control strategy comprises:
when S is pc (δ sj ) When the evaluation result is more than or equal to 0, the evaluation result is output as the policyIs slightly effective;
when S is pc (δ sj )<0 and | S pc |＞＞S xn If so, outputting the evaluation result as invalid strategy;
when S is pc (δ sj )<0 and | S pc |<S xn And if so, outputting the evaluation result as that the strategy is effective.
8. The method of claim 1, wherein the steady state of the power system is maintained by maintaining power angle difference fluctuation between the generators of the power system within a preset interval.
9. A system for evaluating an effect of an emergency control strategy based on a deviation area, the system comprising:
a matching unit for calling a failure emergency control strategy table according to the failure scene information when the power system fails, and determining an online matching emergency control strategy and a simulation equivalent power angle track P dz (δ eq ) And the expected remaining reduction area S xn Wherein, an equivalent power angle locus P is simulated fz (δ eq ) The power angle locus of the generator of the multi-machine system forms a power angle curve of a single-machine infinite system through complementary group inertia center-relative motion transformation, delta eq Is a simulated equivalent power angle under the expected fault, and the expected residual deceleration area S xn Is based on a simulated equivalent power angle track P obtained in an expected fault scene fz (δ eq ) After a virtual mechanical power track and a virtual electromagnetic power track are constructed, the area enclosed by the virtual electromagnetic power track and the virtual mechanical power track is obtained, the virtual mechanical power track is a curve formed by horizontally extending equivalent mechanical power at a point E, the virtual electromagnetic power track is a curve formed by sine prediction of the equivalent electromagnetic power at the point E, and the point E is the farthest point in the first swing process;
a deviation area determination unit for converting the actual generator power angle and rotation speed deviation data measured during the operation of the power system into an actual equivalent power angle locus P after the complementary group inertia center-relative motion sj (δ sj ) According to the actual equivalent power angle trajectory S sj (δ sj ) The actual equivalent power angle delta corresponding to the actual power angle of the generator measured at each moment after the fault occurs sj Determining the actual equivalent electromagnetic power P e-sj (δ sj ) And according to the simulated equivalent power angle trajectory P fz (δ eq ) The actual equivalent power angle delta corresponding to the actual power angle of the generator measured at each moment after the fault occurs sj Determining a simulated equivalent power angle delta eq Equal to the actual equivalent power angle delta sj Time-corresponding simulated equivalent electromagnetic power P e-fz (δ eq ＝δ sj ) And by the simulation equivalent electromagnetic power P e-fz (δ eq ＝δ sj ) And the actual equivalent electromagnetic power P e-sj (δ sj ) Calculating the actual equivalent power angle from delta 0 Swing to delta sj Time of transient deviation area S pc (δ sj ) Wherein the actual equivalent power angle at the time of the fault occurrence is delta 0 ；
A control effect determination unit for determining a transient deviation area S according to a current time pc (δ sj ) Positive and negative values of (1) and comparison S pc (δ sj ) Absolute value of (d) and expected remaining reduction area S xn Determining the effect of the emergency control strategy, wherein the effect comprises strategy effectiveness and strategy ineffectiveness;
and the operation state determining unit is used for determining the operation state of the power system and determining whether to finish the evaluation according to the effect of the emergency control strategy and the operation state of the system.
10. The system of claim 9, wherein the operational status determination unit determines the power system operational status and determining whether to end the evaluation based on the effect of the emergency control strategy and the system operational status comprises:
when the emergency control strategy is effective and the running state of the power system does not reach a steady state, or when the emergency control strategy is ineffective and the running state of the power system is not out of step, returning to the deviation area determining unit;
and when the emergency control strategy is effective and the running state of the power system reaches a steady state, or when the emergency control strategy is ineffective and the running state of the power system is out of step, namely the out-of-step disconnecting device acts, finishing the evaluation.
11. The system according to claim 9 or 10, further comprising a control strategy establishing unit for calculating a simulated equivalent power-angle trajectory P when an emergency control strategy is adopted in a predicted fault scenario fz (δ eq ) And the expected remaining reduction area S xn Forming a fault emergency control strategy table in which an equivalent power angle locus P is simulated fz (δ eq ) The power angle locus of the generator of the multi-machine system is transformed into a power angle curve, delta, of a single-machine infinite system through complementary group inertia center-relative motion eq Is a simulated equivalent power angle under the expected fault.
12. The system according to claim 11, wherein the simulated equivalent power-angle trajectory P generated in the control strategy creation unit fz (δ eq ) And the expected remaining reduction area S xn The method is offline solution or online rolling solution, and is synchronously performed and synchronously stored in the generation process of the emergency control strategy table.
13. The system of claim 12, wherein the control strategy creation unit is configured to create a simulated equivalent power angle trajectory P fz (δ eq ) And the actual equivalent power angle locus P sj (δ sj ) Equating using a complementary cluster inertia center-relative motion transform includes:
for an electric power system with n generators, grouping the n generators by adopting an extended equal-area method, wherein a running disturbed unit belongs to a K group, and the rest units belong to a W group, simplifying the system of the n generators by adopting complementary group inertia center-relative motion transformation and equating the system to a single-machine infinite system, wherein the motion equation is as follows:
in the formula, M eq 、ω eq And delta eq Equivalent inertia, equivalent rotation speed deviation and equivalent power angle, P, of a single-machine infinite system m,eq And P e,eq Equivalent mechanical power and electromagnetic power respectively;
let M i 、ω i And delta i Respectively, the moment of inertia, the rotational speed deviation and the work angle, P, of the ith generator mi And P ei The mechanical power and the electromagnetic power of the ith generator are respectively obtained, and the method for solving the parameters in the formula is as follows:
P m,eq ＝(M W P mK -M K P mW )/M T ；P e,eq ＝(M W P eK -M K P eW )/M T ；
in the formula, subscripts W and K respectively represent a W cluster and a K cluster, and subscript T represents all the generator sets.
14. The system according to claim 13, wherein the deviation area determination unit passes the simulated equivalent electromagnetic power P e-fz (δ eq ＝δ sj ) And the actual equivalent electromagnetic power P e-sj (δ sj ) Calculating the actual equivalent power angle from delta 0 Swing to delta sj Time of transient deviation area S pc (δ sj ) The calculation formula of (2) is as follows:
15. the system according to claim 14, wherein the control effect determination unit determines the transient deviation area S according to the current time pc (δ sj ) Positive and negative of value of (1) and S pc (δ sj ) Absolute value of (d) and expected remaining reduction area S xn The determining of the effect of the emergency control strategy comprises:
when S is pc (δ sj ) When the evaluation result is more than or equal to 0, outputting the evaluation result as effective strategy;
when S is pc (δ sj )<0 and | S pc |＞＞S xn If so, outputting the evaluation result as invalid strategy;
when S is pc (δ sj )<0 and | S pc |<S xn And if so, outputting the evaluation result as that the strategy is effective.
16. The system according to claim 11, wherein the determination of the steady state of the power system by the operation state determination unit means that the fluctuation of the power angle difference between the generators of the power system is maintained at a preset interval.
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