CN116231685B - QPSO-based electric power system inertia and primary frequency modulation capability assessment method - Google Patents

QPSO-based electric power system inertia and primary frequency modulation capability assessment method Download PDF

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CN116231685B
CN116231685B CN202310518388.3A CN202310518388A CN116231685B CN 116231685 B CN116231685 B CN 116231685B CN 202310518388 A CN202310518388 A CN 202310518388A CN 116231685 B CN116231685 B CN 116231685B
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王程
田家祥
毕天姝
胥国毅
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    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
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    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
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    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
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    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
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Abstract

The invention discloses a QPSO-based power system inertia and primary frequency modulation capability assessment method, which belongs to the field of power system frequency stability control and comprises the following steps: the method comprises the steps of monitoring and collecting frequency and active power data of a grid-connected bus of a power plant in real time through a synchronous phasor measurement device, partitioning a power system based on a power grid topology and a disturbed system frequency dynamic response curve, evaluating inertia and primary frequency modulation capacity of each region based on unbalanced power and regional inertia center frequency in the region, and evaluating inertia and primary frequency modulation capacity of the whole power system through weighting and aggregating equivalent inertia time constants and equivalent difference modulation coefficients of each region. By adopting the QPSO-based power system inertia and primary frequency modulation capability assessment method, the real-time tracking of the power system inertia and primary frequency modulation capability can be realized, system scheduling staff is helped to grasp the system frequency safety level in real time, the system operation mode is guided and adjusted, and the system operation stability is improved.

Description

QPSO-based electric power system inertia and primary frequency modulation capability assessment method
Technical Field
The invention relates to the field of power system frequency stability control, in particular to a QPSO-based power system inertia and primary frequency modulation capability assessment method.
Background
With the continuous improvement of the access proportion of new energy, the overall inertia level of the power system is reduced, and the characteristic of uneven frequency modulation capability distribution is increasingly displayed, so that the online evaluation of the inertia and primary frequency modulation capability of the power system by using the measurement data of the synchronous phasor measurement unit (Phasor Measurement Unit, PMU) has important significance.
And the inertia and primary frequency modulation capability of the power system are evaluated on line by taking the apparent space-time distribution difference of the frequency dynamic response of the power system into consideration, so that the feasibility is realized. The zoning result of the system is influenced by the power grid topology and parameters, is related to the system operating point, the disturbance type and the disturbance position, and provides higher requirements for the rapidity of the online evaluation algorithm of the inertia and primary frequency modulation capability of the system in the dynamic zoning scene of the system.
In order to quantitatively analyze the frequency modulation capability of the power system, the system frequency dynamic response process is focused in an inertia response stage and a primary frequency modulation stage. Where inertia plays an important role in maintaining transient stability of the frequency of the power system, the level of inertia of the power system can characterize the ability of the system to dampen frequency changes under unbalanced power disturbances, typically expressed as an inertia time constant. In the primary frequency modulation stage, the synchronous unit speed regulator acts to regulate mechanical power output, and the equivalent difference adjustment coefficient of the power system can represent the frequency supporting capacity of the power system in the primary frequency modulation stage.
Meanwhile, as a new energy source is connected into a power grid through a power electronic converter and replaces a synchronous generator in the system, the inertia level of the system is further reduced, and the primary frequency modulation capability is weakened, so that the online evaluation of the inertia and the primary frequency modulation capability of the power system has important significance, and the online evaluation method can help system dispatcher to grasp the frequency safety level of the system in real time and guide and adjust the operation mode of the system, and improves the operation stability of the system.
In the aspect of system inertia and primary frequency modulation capability assessment based on PMU measurement data, the calculated amount is large when a single generator is taken as a minimum assessment unit, the rapid requirement of online assessment cannot be met, and when the whole system is taken as an assessment object, the problems of difficult acquisition of unbalanced power, poor frequency aggregation effect and low assessment precision of frequency modulation capability are faced.
Disclosure of Invention
In order to solve the problems, the invention provides the QPSO-based power system inertia and primary frequency modulation capability evaluation method, which can realize real-time tracking of the power system inertia and primary frequency modulation capability, help system schedulers to master the system frequency safety level in real time and guide and adjust the system operation mode, and improve the system operation stability.
In order to achieve the above purpose, the invention provides a QPSO-based power system inertia and primary frequency modulation capability assessment method, which comprises the following steps:
s1, monitoring and collecting frequency and active power data of a grid-connected busbar of a power plant in real time through a synchronous phasor measurement device;
s2, taking the fact that the frequency of the power system has space-time distribution characteristics into consideration, and partitioning the power system based on the power grid topology and a disturbed system frequency dynamic response curve;
s3, evaluating inertia of each area and primary frequency modulation capacity based on unbalanced power in the area and area inertia center frequency;
and S4, evaluating inertia and primary frequency modulation capacity of the whole power system by carrying out weighted aggregation on the equivalent inertia time constant and the equivalent difference modulation coefficient of each region.
Preferably, the step S2 specifically includes the following steps:
based on Euclidean distance and K-means algorithm, the collected power plant grid-connected busbar frequency time series are clustered, the frequency time series and the cluster center closest to the frequency time series are classified, and the power system is divided into a plurality of areas by combining the power grid topology.
Preferably, the step S2 specifically includes the following steps:
s21, measuring the frequency discrete time sequence of the node A through the PMU
Figure SMS_1
And frequency discrete time sequence of node B +.>
Figure SMS_2
For frequency discrete time series +.>
Figure SMS_3
And->
Figure SMS_4
Satisfy->
Figure SMS_5
,/>
Figure SMS_6
,/>
Figure SMS_7
Is the length of the frequency discrete time series;
s22, representing the similarity between time sequences of different frequencies by using Euclidean distance, wherein the distance index is shown as follows:
Figure SMS_8
(1)
in the method, in the process of the invention,
Figure SMS_9
for frequency time series->
Figure SMS_10
And->
Figure SMS_11
A Euclidean distance between them;
s23, clustering the frequencies by adopting a K-means algorithm based on the defined Euclidean distance index;
s24, dividing the power system into a plurality of areas by combining the power grid topology.
Preferably, the step S23 specifically includes the following steps:
s231, designating the cluster number M, and calculating the distance between the sample and the cluster center assuming that each cluster has a center point:
Figure SMS_12
(2)
in the method, in the process of the invention,
Figure SMS_13
for the frequency-time series of acquisition, +.>
Figure SMS_14
For the center point vector of the cluster where the sample is located, the sample and the nearest center point are divided into a cluster, +.>
Figure SMS_15
For calculating the distance between two frequency time sequences, < >>
Figure SMS_16
For the length of the frequency discrete time series, +.>
Figure SMS_17
Is the distance between the sample and the cluster center;
s232, randomly selecting M points as center points of each cluster, and iteratively executing the following two steps:
finding respective sample data for each center point, and dividing the sample data into center points closest to each center point;
and (3) recalculating the center point in each cluster, wherein the new center point is the arithmetic average value of members in the cluster, so that the calculated L value of the new center point is necessarily smaller than or equal to the original L value, and the iterative loop is carried out until the clustering algorithm converges and then exits.
Preferably, the step S3 specifically includes the following steps:
s31, writing out a forward differential model and a fitness function of regional inertia evaluation, respectively aggregating frequency and active power data of a power plant grid-connected bus in each region, and dynamically estimating equivalent inertia time constants of each region by adopting a quantum particle swarm optimization algorithm in the length of each data sliding window by utilizing frequency data before primary frequency modulation action;
s32, writing out a forward differential model and a fitness function of regional primary frequency modulation capability evaluation, calculating regional inertia response power according to the evaluation result of the equivalent inertia time constant of each region, correcting unbalanced power of a system, and dynamically estimating the equivalent difference adjustment coefficient of each region by adopting a quantum particle swarm optimization algorithm in each data sliding window length by utilizing frequency data after primary frequency modulation action;
s33, setting the sliding window length of the estimated data, the data sampling time interval and the action dead zone of the synchronous machine set speed regulator, writing a forward differential model and a fitness function for estimating the regional inertia and primary frequency modulation capacity into a quantum particle swarm optimization algorithm for iteration until the termination condition of the quantum particle swarm optimization algorithm is met, and outputting the global optimal position of the particle swarm, namely the regional equivalent inertia time constant and the equivalent difference adjustment coefficient.
Preferably, the step S31 specifically includes the following steps:
s311, equating the power system of each region into a synchronous generator, and describing the active-frequency dynamic response process by the following rotor motion equation under unbalanced disturbance:
Figure SMS_18
(3)
wherein, the liquid crystal display device comprises a liquid crystal display device,
Figure SMS_20
is the power angle of the generator, < >>
Figure SMS_23
Rated frequency of generator, < >>
Figure SMS_25
For generator frequency deviation, < >>
Figure SMS_21
Is generator inertia time constant, +.>
Figure SMS_22
And->
Figure SMS_24
Respectively the mechanical power per unit value and the electromagnetic power per unit value of the generator>
Figure SMS_26
Is the damping coefficient of the generator, < >>
Figure SMS_19
Is a time-domain differential operator;
s312, in the inertia response stage after the system is disturbed, the system frequency does not exceed the primary frequency modulation dead zone, and the mechanical power output of the generator is considered to be stable at the moment, namely
Figure SMS_27
Simultaneously ignoring the influence of the damping coefficient of the generator, let ∈ ->
Figure SMS_28
The above formula is written as:
Figure SMS_29
(4)
the output of the generator before disturbance occurs meets
Figure SMS_30
The following formula is obtained:
Figure SMS_31
(5)
in the method, in the process of the invention,
Figure SMS_32
and->
Figure SMS_33
Mechanical power and electromagnetic power of the generator before the disturbance occurs, respectively,>
Figure SMS_34
for the electromagnetic power increment after the disturbance occurs, +.>
Figure SMS_35
An equivalent inertial time constant to be evaluated for the regional power system;
s313, obtaining a fitting formula of the following frequency curve by forward difference of the formula:
Figure SMS_36
(6)
in the method, in the process of the invention,
Figure SMS_37
fitting for Quantum particle swarm Algorithm +.>
Figure SMS_38
Time-of-day frequency deviation +.>
Figure SMS_39
Fitting for Quantum particle swarm Algorithm +.>
Figure SMS_40
Time-of-day frequencyDeviation (F)>
Figure SMS_41
For the sampling time interval of the frequency data, +.>
Figure SMS_42
Is->
Figure SMS_43
Unbalanced power of the time zone power system;
s314, estimating an adaptability function of an equivalent inertial time constant of the regional power system, wherein the adaptability function is shown in the following formula:
Figure SMS_44
(7)
in the method, in the process of the invention,
Figure SMS_45
to characterize the fitness function of the frequency curve fitting effect, +.>
Figure SMS_46
Frequency deviation fitted for quantum particle swarm algorithm.
Preferably, the step S32 specifically includes the following steps:
s321, in a primary frequency modulation stage after system disturbance, the system frequency exceeds a primary frequency modulation dead zone, a generator speed regulator in the area starts to act, mechanical power output changes, and at the moment, the mechanical power increment of a generator set meets the following transfer function form:
Figure SMS_47
(8)
in the method, in the process of the invention,
Figure SMS_48
for the generator mechanical power increment after the disturbance has occurred, +.>
Figure SMS_49
Equivalent difference coefficient to be evaluated for regional power system, +.>
Figure SMS_50
For the system frequency +.>
Figure SMS_51
Is a primary frequency modulation action dead zone->
Figure SMS_52
Equivalent time constant of first-order inertia link of speed regulator, < >>
Figure SMS_53
Is a frequency domain differential operator;
s322, evaluating the result based on the equivalent inertial time constant of the regional power system
Figure SMS_54
And (3) taking inertia effect into account in the primary frequency modulation process, and correcting the unbalanced regional power into:
Figure SMS_55
(9)
Figure SMS_56
(10)
in the method, in the process of the invention,
Figure SMS_57
unbalanced power for a regional power system;
s323, forward difference of the transfer function is obtained:
Figure SMS_58
(11)
in the method, in the process of the invention,
Figure SMS_59
is->
Figure SMS_60
Frequency deviation of time,/->
Figure SMS_61
Fitting for Quantum particle swarm Algorithm +.>
Figure SMS_62
Time zone power system unbalanced power, +.>
Figure SMS_63
Fitting for Quantum particle swarm Algorithm +.>
Figure SMS_64
Unbalanced power of the power system in the time zone;
s324, estimating an adaptability function of an equivalent difference adjustment coefficient of the regional power system, wherein the adaptability function is shown in the following formula:
Figure SMS_65
(12)
in the method, in the process of the invention,
Figure SMS_66
to characterize the fitness function of the power curve fitting effect, +.>
Figure SMS_67
And (5) unbalanced power of the regional power system fitted for the quantum particle swarm algorithm.
Preferably, the step S33 specifically includes the following steps:
s331, determining dimension of quantum particle swarm target search space
Figure SMS_68
I.e. the number of decision variables to be solved; at this time, assume thatNThe particles form a group, and the movement of each particle not only needs to consider the optimal position searched by the particle, but also comprehensively considers the optimal position searched by the group; in quantum space, the velocity and position of the particles cannot be determined simultaneously, so the wavefunction +.>
Figure SMS_69
Describing the state of the particle, wherein->
Figure SMS_70
Is a position vector of a particle in a three-dimensional space, and the probability density of the occurrence of the particle at a certain point in the space is represented by the square of a wave function modulus, namely:
Figure SMS_71
(13)
wherein Q is a probability density function that satisfies a normalization condition:
Figure SMS_72
(14);
s332, describing the movement of particles in quantum mechanics by a Schrodinger equation:
Figure SMS_73
(15)
Figure SMS_74
(16)
wherein, the liquid crystal display device comprises a liquid crystal display device,
Figure SMS_75
is Manhattan operator,)>
Figure SMS_76
Is Planck constant, +.>
Figure SMS_77
For particle quality, < >>
Figure SMS_78
Is the potential field where the particles are located;
s333, consider a single particle
Figure SMS_79
The point is one-dimensional +.>
Figure SMS_80
In the potential well, attracting particlesSon->
Figure SMS_81
Marked as->
Figure SMS_82
The position of the particles is marked->
Figure SMS_83
The potential energy function is as follows:
Figure SMS_84
(17)
in the method, in the process of the invention,
Figure SMS_85
is Euler-Ma Xieluo Niconstant;
s334, determining the position of the particles by adopting a Monte Carlo method:
Figure SMS_86
(18)
Figure SMS_87
(19)
wherein, the liquid crystal display device comprises a liquid crystal display device,Lis that
Figure SMS_88
Characteristic length of potential well->
Figure SMS_89
Is section->
Figure SMS_90
On uniformly distributed random numbers, i.e. +.>
Figure SMS_91
The particles are
Figure SMS_92
First->
Figure SMS_93
The basic evolution equation for the coordinates of the dimensions is:
Figure SMS_94
(20)
in the method, in the process of the invention,
Figure SMS_97
for the time t+1 particle->
Figure SMS_101
First->
Figure SMS_104
Coordinates of dimension->
Figure SMS_98
For time t particle->
Figure SMS_100
First->
Figure SMS_103
The attractor of the dimension is a three-dimensional attractor,
Figure SMS_105
for time t particle->
Figure SMS_95
First->
Figure SMS_99
Wei->
Figure SMS_102
Characteristic length of potential well->
Figure SMS_106
For time interval t->
Figure SMS_96
Random numbers uniformly distributed on the base;
s335, introducing an average best position
Figure SMS_107
Defined as the average of the best positions of all particle individuals,/->
Figure SMS_108
By passing through
Figure SMS_109
To evaluate, the evolution equation of the particles is rewritten as:
Figure SMS_110
(21)
Figure SMS_111
(22)
wherein, the liquid crystal display device comprises a liquid crystal display device,
Figure SMS_112
for the contraction-expansion coefficient, +.>
Figure SMS_113
For time t particle->
Figure SMS_114
First->
Figure SMS_115
Coordinates of dimension->
Figure SMS_116
For the number of particle populations,
Figure SMS_117
is->
Figure SMS_118
The best position is averaged.
Preferably, the step S4 specifically includes the following steps:
setting reference capacity of the power system, aggregating evaluation results of inertia and primary frequency modulation capacity of each area, and calculating equivalent inertia time constant and equivalent difference adjustment coefficient of the power system on line.
Preferably, the step S4 specifically includes the following steps:
dividing an electrical power system into
Figure SMS_119
Setting rated capacity of the system, aggregating evaluation results of inertia and primary frequency modulation capacity of each region, and calculating equivalent inertia time constant and equivalent difference adjustment coefficient of the power system on line;
wherein, the equivalent inertia of the power system is expressed as:
Figure SMS_120
(23)
in the method, in the process of the invention,
Figure SMS_121
for the equivalent inertia of the power system->
Figure SMS_122
For the kinetic energy stored by all generators in the area, +.>
Figure SMS_123
Equivalent inertial time constant for each region, +.>
Figure SMS_124
Rated capacity for each zone;
the system equivalent inertial time constant is represented by a weighted average of the equivalent inertial time constants of the respective regions:
Figure SMS_125
(24)
wherein, the liquid crystal display device comprises a liquid crystal display device,
Figure SMS_126
is the equivalent inertia time constant of the electric power system, +.>
Figure SMS_127
Is a reference capacity of the power system;
likewise, the power system equivalent difference coefficient is represented by a weighted average of the regional equivalent difference coefficients:
Figure SMS_128
(25)
in the method, in the process of the invention,
Figure SMS_129
is the equivalent difference adjustment coefficient of the power system, +.>
Figure SMS_130
Is the equivalent difference adjustment coefficient of each region.
The invention has the following beneficial effects:
the synchronous phasor measurement device configured at the positions of the grid-connected buses and other key buses of the power plant is fully utilized, the frequency and active power data of the buses are collected, the topological structure of the power grid is obtained, real-time tracking of the inertia and primary frequency modulation capacity of the power system can be realized, system scheduling staff is helped to master the frequency safety level of the system in real time, the operation mode of the system is guided and adjusted, and the operation stability of the system is improved.
The technical scheme of the invention is further described in detail through the drawings and the embodiments.
Drawings
FIG. 1 is a flow chart of a QPSO-based power system inertia and primary frequency modulation capability assessment method of the present invention;
FIG. 2 is a schematic diagram of an IEEE 39 node system topology as employed by an embodiment of the present invention;
FIG. 3 is a graph of a result of frequency clustering of busbar nodes according to an embodiment of the present invention;
FIG. 4 is a schematic diagram of an IEEE 39 node system partition in accordance with an embodiment of the invention;
FIG. 5 is a box plot of the results of the equivalent inertial time constant evaluation for each region in an embodiment of the present invention;
FIG. 6 is a box diagram of the evaluation result of the equivalent adjustment coefficient of each region according to the embodiment of the invention;
FIG. 7 is a graph of dynamic evaluation results of inertia of an electric power system according to an embodiment of the present invention;
fig. 8 is a graph of a dynamic evaluation result of primary frequency modulation capability of an electric power system according to an embodiment of the invention.
Detailed Description
The present invention will be further described with reference to the accompanying drawings, and it should be noted that, while the present embodiment provides a detailed implementation and a specific operation process on the premise of the present technical solution, the protection scope of the present invention is not limited to the present embodiment.
The QPSO-based power system inertia and primary frequency modulation capability evaluation method comprises the following steps of:
s1, monitoring and collecting frequency and active power data of a grid-connected busbar of a power plant in real time through a synchronous phasor measurement device;
in the power system in this embodiment, synchronous phasor measurement devices should be configured at grid-connected buses of the power plant, and other key bus positions should be configured as much as possible.
S2, taking the fact that the frequency of the power system has space-time distribution characteristics into consideration, and partitioning the power system based on the power grid topology and a disturbed system frequency dynamic response curve;
preferably, the step S2 specifically includes the following steps:
the frequency of the power system has space-time distribution characteristics, and the similarity of frequency and time sequences of generator sets or busbar nodes with similar distances is higher, so that the acquired power plant grid-connected busbar frequency and time sequences are clustered based on Euclidean distance and a K-means algorithm, the frequency and time sequences and cluster centers with the closest distances are classified, and the power system is divided into a plurality of areas by combining with the power grid topology.
Preferably, the step S2 specifically includes the following steps:
s21, measuring the frequency discrete time sequence of the node A through the PMU
Figure SMS_131
And frequency discrete time sequence of node B +.>
Figure SMS_132
For frequency discrete time series +.>
Figure SMS_133
And->
Figure SMS_134
Satisfy->
Figure SMS_135
,/>
Figure SMS_136
,/>
Figure SMS_137
Is the length of the frequency discrete time series;
s22, representing the similarity between time sequences of different frequencies by using Euclidean distance, wherein the distance index is shown as follows:
Figure SMS_138
(1)
in the method, in the process of the invention,
Figure SMS_139
for frequency time series->
Figure SMS_140
And->
Figure SMS_141
A Euclidean distance between them;
s23, clustering the frequencies by adopting a K-means algorithm based on the defined Euclidean distance index;
preferably, the step S23 specifically includes the following steps:
s231, designating the cluster number M, and calculating the distance between the sample and the cluster center assuming that each cluster has a center point:
Figure SMS_142
(2)
in the method, in the process of the invention,
Figure SMS_143
for the frequency-time series of acquisition, +.>
Figure SMS_144
For the center point vector of the cluster where the sample is located, the sample and the nearest center point are divided into a cluster, +.>
Figure SMS_145
For calculating the distance between two frequency time sequences, < >>
Figure SMS_146
For the length of the frequency discrete time series, +.>
Figure SMS_147
Is the distance between the sample and the cluster center;
s232, randomly selecting M points as center points of each cluster, and iteratively executing the following two steps:
finding respective sample data for each center point, and dividing the sample data into center points closest to each center point;
and (3) recalculating the center point in each cluster, wherein the new center point is the arithmetic average value of members in the cluster, so that the calculated L value of the new center point is necessarily smaller than or equal to the original L value, and the iterative loop is carried out until the clustering algorithm converges and then exits.
S24, dividing the power system into a plurality of areas by combining the power grid topology.
S3, evaluating inertia of each area and primary frequency modulation capacity based on unbalanced power in the area and area inertia center frequency;
preferably, the step S3 specifically includes the following steps:
s31, writing out a forward differential model and a fitness function of regional inertia evaluation, respectively aggregating frequency and active power data of a power plant grid-connected bus in each region, and dynamically estimating equivalent inertia time constants of each region by adopting a quantum particle swarm optimization algorithm in the length of each data sliding window by utilizing frequency data before primary frequency modulation action;
preferably, the step S31 specifically includes the following steps:
s311, the frequency dynamic response of the regional power systems is similar, each regional power system is equivalent to a synchronous generator, and the active-frequency dynamic response process is described by the following rotor motion equation under unbalanced disturbance:
Figure SMS_148
(3)
wherein, the liquid crystal display device comprises a liquid crystal display device,
Figure SMS_150
is the power angle of the generator, < >>
Figure SMS_152
Rated frequency of generator, < >>
Figure SMS_154
For generator frequency deviation, < >>
Figure SMS_151
Is generator inertia time constant, +.>
Figure SMS_153
And->
Figure SMS_155
Respectively the mechanical power per unit value and the electromagnetic power per unit value of the generator>
Figure SMS_156
Is the damping coefficient of the generator, < >>
Figure SMS_149
Is a time-domain differential operator;
s312, in the inertia response stage after the system is disturbed, the system frequency does not exceed the primary frequency modulation dead zone, and the mechanical power output of the generator is considered to be stable at the moment, namely
Figure SMS_157
Simultaneously ignoring the influence of the damping coefficient of the generator, let ∈ ->
Figure SMS_158
The above formula is written as:
Figure SMS_159
(4)
the output of the generator before disturbance occurs meets
Figure SMS_160
The following formula is obtained:
Figure SMS_161
(5)
in the method, in the process of the invention,
Figure SMS_162
and->
Figure SMS_163
Mechanical power and electromagnetic power of the generator before the disturbance occurs, respectively,>
Figure SMS_164
for the electromagnetic power increment after the disturbance occurs, +.>
Figure SMS_165
An equivalent inertial time constant to be evaluated for the regional power system;
s313, obtaining a fitting formula of the following frequency curve by forward difference of the formula:
Figure SMS_166
(6)
in the method, in the process of the invention,
Figure SMS_167
fitting for Quantum particle swarm Algorithm +.>
Figure SMS_168
Time-of-day frequency deviation +.>
Figure SMS_169
Algorithm for quantum particle swarmFitting +.>
Figure SMS_170
Time-of-day frequency deviation +.>
Figure SMS_171
For the sampling time interval of the frequency data, +.>
Figure SMS_172
Is->
Figure SMS_173
Unbalanced power of the time zone power system;
s314, estimating an adaptability function of an equivalent inertial time constant of the regional power system, wherein the adaptability function is shown in the following formula:
Figure SMS_174
(7)
in the method, in the process of the invention,
Figure SMS_175
to characterize the fitness function of the frequency curve fitting effect, +.>
Figure SMS_176
Frequency deviation fitted for quantum particle swarm algorithm.
S32, writing out a forward differential model and a fitness function of regional primary frequency modulation capability evaluation, calculating regional inertia response power according to the evaluation result of the equivalent inertia time constant of each region, correcting unbalanced power of a system, and dynamically estimating the equivalent difference adjustment coefficient of each region by adopting a quantum particle swarm optimization algorithm in each data sliding window length by utilizing frequency data after primary frequency modulation action;
preferably, the step S32 specifically includes the following steps:
s321, in a primary frequency modulation stage after system disturbance, the system frequency exceeds a primary frequency modulation dead zone, a generator speed regulator in the area starts to act, mechanical power output changes, and at the moment, the mechanical power increment of a generator set meets the following transfer function form:
Figure SMS_177
(8)
in the method, in the process of the invention,
Figure SMS_178
for the generator mechanical power increment after the disturbance has occurred, +.>
Figure SMS_179
Equivalent difference coefficient to be evaluated for regional power system, +.>
Figure SMS_180
For the system frequency +.>
Figure SMS_181
Is a primary frequency modulation action dead zone->
Figure SMS_182
Equivalent time constant of first-order inertia link of speed regulator, < >>
Figure SMS_183
Is a frequency domain differential operator;
s322, evaluating the result based on the equivalent inertial time constant of the regional power system
Figure SMS_184
And (3) taking inertia effect into account in the primary frequency modulation process, and correcting the unbalanced regional power into:
Figure SMS_185
(9)
Figure SMS_186
(10)
in the method, in the process of the invention,
Figure SMS_187
unbalanced power for a regional power system;
s323, forward difference of the transfer function is obtained:
Figure SMS_188
(11)
in the method, in the process of the invention,
Figure SMS_189
is->
Figure SMS_190
Frequency deviation of time,/->
Figure SMS_191
Fitting for Quantum particle swarm Algorithm +.>
Figure SMS_192
Time zone power system unbalanced power, +.>
Figure SMS_193
Fitting for Quantum particle swarm Algorithm +.>
Figure SMS_194
Unbalanced power of the power system in the time zone;
s324, estimating an adaptability function of an equivalent difference adjustment coefficient of the regional power system, wherein the adaptability function is shown in the following formula:
Figure SMS_195
(12)
in the method, in the process of the invention,
Figure SMS_196
to characterize the fitness function of the power curve fitting effect, +.>
Figure SMS_197
And (5) unbalanced power of the regional power system fitted for the quantum particle swarm algorithm.
S33, setting the sliding window length of the estimated data, the data sampling time interval and the action dead zone of the synchronous machine set speed regulator, writing a forward differential model and a fitness function for estimating the regional inertia and primary frequency modulation capacity into a quantum particle swarm optimization algorithm for iteration until the termination condition of the quantum particle swarm optimization algorithm is met, and outputting the global optimal position of the particle swarm, namely the regional equivalent inertia time constant and the equivalent difference adjustment coefficient.
Preferably, the step S33 specifically includes the following steps:
s331, determining dimension of quantum particle swarm target search space
Figure SMS_198
I.e. the number of decision variables to be solved; at this time, assume thatNThe particles form a group, and the movement of each particle not only needs to consider the optimal position searched by the particle, but also comprehensively considers the optimal position searched by the group; in quantum space, the velocity and position of the particles cannot be determined simultaneously, so the wavefunction +.>
Figure SMS_199
Describing the state of the particle, wherein->
Figure SMS_200
Is a position vector of a particle in a three-dimensional space, and the probability density of the occurrence of the particle at a certain point in the space is represented by the square of a wave function modulus, namely:
Figure SMS_201
(13)
wherein Q is a probability density function that satisfies a normalization condition:
Figure SMS_202
(14);
s332, describing the movement of particles in quantum mechanics by a Schrodinger equation:
Figure SMS_203
(15)
Figure SMS_204
(16)
wherein, the liquid crystal display device comprises a liquid crystal display device,
Figure SMS_205
is Manhattan operator,)>
Figure SMS_206
Is Planck constant, +.>
Figure SMS_207
For particle quality, < >>
Figure SMS_208
Is the potential field where the particles are located;
s333, consider a single particle
Figure SMS_209
The point is one-dimensional +.>
Figure SMS_210
Motion in the potential well, attractor of particles +.>
Figure SMS_211
Marked as->
Figure SMS_212
The position of the particles is marked->
Figure SMS_213
The potential energy function is as follows:
Figure SMS_214
(17)
in the method, in the process of the invention,
Figure SMS_215
is Euler-Ma Xieluo Niconstant;
s334, determining the position of the particles by adopting a Monte Carlo method:
Figure SMS_216
(18)
Figure SMS_217
(19)
wherein, the liquid crystal display device comprises a liquid crystal display device,Lis that
Figure SMS_218
Characteristic length of potential well->
Figure SMS_219
Is section->
Figure SMS_220
On uniformly distributed random numbers, i.e. +.>
Figure SMS_221
The particles are
Figure SMS_222
First->
Figure SMS_223
The basic evolution equation for the coordinates of the dimensions is:
Figure SMS_224
(20)
in the method, in the process of the invention,
Figure SMS_226
for the time t+1 particle->
Figure SMS_231
First->
Figure SMS_234
Coordinates of dimension->
Figure SMS_227
For time t particle->
Figure SMS_230
First->
Figure SMS_233
Dimension(s)The suction device is used for sucking the liquid,
Figure SMS_236
for time t particle->
Figure SMS_225
First->
Figure SMS_229
Wei->
Figure SMS_232
Characteristic length of potential well->
Figure SMS_235
For time interval t->
Figure SMS_228
Random numbers uniformly distributed on the base;
s335, introducing an average best position
Figure SMS_237
Defined as the average of the best positions of all particle individuals,/->
Figure SMS_238
By passing through
Figure SMS_239
To evaluate, the evolution equation of the particles is rewritten as:
Figure SMS_240
(21)
Figure SMS_241
(22)
wherein, the liquid crystal display device comprises a liquid crystal display device,
Figure SMS_242
for the contraction-expansion coefficient, +.>
Figure SMS_243
For time t particle->
Figure SMS_244
First->
Figure SMS_245
Coordinates of dimension->
Figure SMS_246
For particle population quantity, +.>
Figure SMS_247
Is->
Figure SMS_248
The best position is averaged.
And S4, evaluating inertia and primary frequency modulation capacity of the whole power system by carrying out weighted aggregation on the equivalent inertia time constant and the equivalent difference modulation coefficient of each region.
Preferably, the step S4 specifically includes the following steps:
setting reference capacity of the power system, aggregating evaluation results of inertia and primary frequency modulation capacity of each area, and calculating equivalent inertia time constant and equivalent difference adjustment coefficient of the power system on line.
Preferably, the step S4 specifically includes the following steps:
dividing an electrical power system into
Figure SMS_249
Setting rated capacity of the system, aggregating evaluation results of inertia and primary frequency modulation capacity of each region, and calculating equivalent inertia time constant and equivalent difference adjustment coefficient of the power system on line;
wherein, the equivalent inertia of the power system is expressed as:
Figure SMS_250
(23)
in the method, in the process of the invention,
Figure SMS_251
for the equivalent inertia of the power system->
Figure SMS_252
For the kinetic energy stored by all generators in the area, +.>
Figure SMS_253
Equivalent inertial time constant for each region, +.>
Figure SMS_254
Rated capacity for each zone;
the system equivalent inertial time constant is represented by a weighted average of the equivalent inertial time constants of the respective regions:
Figure SMS_255
(24)
wherein, the liquid crystal display device comprises a liquid crystal display device,
Figure SMS_256
is the equivalent inertia time constant of the electric power system, +.>
Figure SMS_257
Is a reference capacity of the power system;
likewise, the power system equivalent difference coefficient is represented by a weighted average of the regional equivalent difference coefficients:
Figure SMS_258
(25)
in the method, in the process of the invention,
Figure SMS_259
is the equivalent difference adjustment coefficient of the power system, +.>
Figure SMS_260
Is the equivalent difference adjustment coefficient of each region.
The method according to the invention is illustrated by means of a specific example:
as shown in fig. 2, based on the system, the system performs the evaluation of inertia and primary frequency modulation capability of the power system based on the quantum particle swarm optimization algorithm and taking into account the dynamic response partition of the system frequency, and the operation steps are as follows:
1. a50 MW disturbance with a sudden load increase is arranged at the position of an IEEE 39 node system bus 25, and the system frequency passes through a primary frequency modulation action dead zone of a synchronous machine speed regulator. Firstly, collecting the frequency of a grid-connected bus position of a power plant for system partition; and secondly, collecting active power data of a grid-connected bus of the power plant for evaluating inertia and primary frequency modulation capability of the power system.
2. Based on the Euclidean distance and the K-means clustering algorithm, the frequency is clustered, and as can be seen from fig. 3, the space-time distribution of the frequency dynamic response of the IEEE 39 node system has a difference. According to the frequency clustering result of the bus nodes, the system is divided into a plurality of areas, the frequency dynamic response curves of the bus nodes in each area are similar, and the partitioning result of the system is shown in fig. 4.
3. Setting the sliding window length of inertia evaluation data, the data sampling time interval and the action dead zone of a synchronous machine set speed regulator, writing a forward differential model and a fitness function of regional inertia evaluation into a quantum particle swarm optimization algorithm for iteration when the frequency does not exceed the primary frequency modulation action dead zone until the termination condition of the quantum particle swarm optimization algorithm is met, and outputting the global optimal position of the particle swarm, namely the regional equivalent inertia time constant, wherein the regional equivalent inertia time constant evaluation result box diagram is shown in figure 5.
TABLE 1 estimation error of equivalent inertial time constant of the method of the invention
Figure SMS_261
As can be seen from table 1, the estimation error of the equivalent inertial time constant is not more than 5%.
4. And correcting unbalanced power of each region by using an evaluation result of an equivalent inertia time constant, when the frequency exceeds a primary frequency modulation action dead zone, writing a forward differential model and an adaptability function for primary frequency modulation capability evaluation into a quantum particle swarm optimization algorithm for iteration until a termination condition of the quantum particle swarm optimization algorithm is met, and outputting a global optimal position of the particle swarm, namely a region equivalent difference adjustment coefficient, wherein a box diagram of the evaluation result of the region equivalent difference adjustment coefficient is shown in fig. 6.
TABLE 2 estimation error of equivalent differential coefficient in the method of the invention
Figure SMS_262
As can be seen from table 2, the estimation error of the equivalent difference coefficient is not more than 10%.
5. The system equivalent inertia time constant is represented by the weighted average of the equivalent inertia time constants of all areas, and the dynamic evaluation result is shown in fig. 7; similarly, the system equivalent difference coefficient is represented by a weighted average of the difference coefficients, and the dynamic evaluation result is shown in fig. 8.
Therefore, the system and the method can realize real-time tracking of the inertia and primary frequency modulation capacity of the power system, help system schedulers to master the safety level of the system frequency in real time and guide and adjust the operation mode of the system, and improve the operation stability of the system.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention and not for limiting it, and although the present invention has been described in detail with reference to the preferred embodiments, it will be understood by those skilled in the art that: the technical scheme of the invention can be modified or replaced by the same, and the modified technical scheme cannot deviate from the spirit and scope of the technical scheme of the invention.

Claims (7)

1. The power system inertia and primary frequency modulation capability assessment method based on QPSO is characterized by comprising the following steps of: the method comprises the following steps:
s1, monitoring and collecting frequency and active power data of a grid-connected busbar of a power plant in real time through a synchronous phasor measurement device;
s2, taking the fact that the frequency of the power system has space-time distribution characteristics into consideration, and partitioning the power system based on the power grid topology and a disturbed system frequency dynamic response curve;
s3, evaluating inertia of each area and primary frequency modulation capacity based on unbalanced power in the area and area inertia center frequency;
the step S3 specifically comprises the following steps:
s31, writing out a forward differential model and a fitness function of regional inertia evaluation, respectively aggregating frequency and active power data of a power plant grid-connected bus in each region, and dynamically estimating equivalent inertia time constants of each region by adopting a quantum particle swarm optimization algorithm in the length of each data sliding window by utilizing frequency data before primary frequency modulation action;
s32, writing out a forward differential model and a fitness function of regional primary frequency modulation capability evaluation, calculating regional inertia response power according to the evaluation result of the equivalent inertia time constant of each region, correcting unbalanced power of a system, and dynamically estimating the equivalent difference adjustment coefficient of each region by adopting a quantum particle swarm optimization algorithm in each data sliding window length by utilizing frequency data after primary frequency modulation action;
s33, setting a sliding window length of evaluation data, a data sampling time interval and a synchronous unit speed regulator action dead zone, writing a forward differential model and a fitness function for evaluating regional inertia and primary frequency modulation capacity into a quantum particle swarm optimization algorithm for iteration until the termination condition of the quantum particle swarm optimization algorithm is met, and outputting the global optimal position of the particle swarm, namely a regional equivalent inertia time constant and an equivalent difference adjustment coefficient;
the step S31 specifically includes the following steps:
s311, equating the power system of each region into a synchronous generator, and describing the active-frequency dynamic response process by the following rotor motion equation under unbalanced disturbance:
Figure QLYQS_1
(3)
wherein, the liquid crystal display device comprises a liquid crystal display device,
Figure QLYQS_4
is the power angle of the generator, < >>
Figure QLYQS_6
Rated frequency of generator, < >>
Figure QLYQS_8
For generator frequency deviation, < >>
Figure QLYQS_3
Is generator inertia time constant, +.>
Figure QLYQS_5
And->
Figure QLYQS_7
Respectively the mechanical power per unit value and the electromagnetic power per unit value of the generator>
Figure QLYQS_9
Is the damping coefficient of the generator, < >>
Figure QLYQS_2
Is a time-domain differential operator;
s312, in the inertia response stage after the system is disturbed, the system frequency does not exceed the primary frequency modulation dead zone, and the mechanical power output of the generator is considered to be stable at the moment, namely
Figure QLYQS_10
Simultaneously ignoring the influence of the damping coefficient of the generator, let ∈ ->
Figure QLYQS_11
The above formula is written as:
Figure QLYQS_12
(4)
the output of the generator before disturbance occurs meets
Figure QLYQS_13
The following formula is obtained:
Figure QLYQS_14
(5)
in the method, in the process of the invention,
Figure QLYQS_15
and->
Figure QLYQS_16
Mechanical power and electromagnetic power of the generator before the disturbance occurs, respectively,>
Figure QLYQS_17
for the electromagnetic power increment after the disturbance occurs, +.>
Figure QLYQS_18
An equivalent inertial time constant to be evaluated for the regional power system;
s313, obtaining a fitting formula of the following frequency curve by forward difference of the formula:
Figure QLYQS_19
(6)
in the method, in the process of the invention,
Figure QLYQS_20
fitting for Quantum particle swarm Algorithm +.>
Figure QLYQS_21
Time-of-day frequency deviation +.>
Figure QLYQS_22
Fitting for Quantum particle swarm Algorithm +.>
Figure QLYQS_23
Time-of-day frequency deviation +.>
Figure QLYQS_24
For the sampling time interval of the frequency data, +.>
Figure QLYQS_25
Is->
Figure QLYQS_26
Unbalanced power of the time zone power system;
s314, estimating an adaptability function of an equivalent inertial time constant of the regional power system, wherein the adaptability function is shown in the following formula:
Figure QLYQS_27
(7)
in the method, in the process of the invention,
Figure QLYQS_28
to characterize the fitness function of the frequency curve fitting effect, +.>
Figure QLYQS_29
Fitting frequency deviation for a quantum particle swarm algorithm;
the step S32 specifically includes the following steps:
s321, in a primary frequency modulation stage after system disturbance, the system frequency exceeds a primary frequency modulation dead zone, a generator speed regulator in the area starts to act, mechanical power output changes, and at the moment, the mechanical power increment of a generator set meets the following transfer function form:
Figure QLYQS_30
(8)
in the method, in the process of the invention,
Figure QLYQS_31
for the generator mechanical power increment after the disturbance has occurred, +.>
Figure QLYQS_32
Equivalent difference coefficient to be evaluated for regional power system, +.>
Figure QLYQS_33
For the system frequency +.>
Figure QLYQS_34
Is a primary frequency modulation action dead zone->
Figure QLYQS_35
Equivalent time constant of first-order inertia link of speed regulator, < >>
Figure QLYQS_36
Is a frequency domain differential operator;
s322, evaluating the result based on the equivalent inertial time constant of the regional power system
Figure QLYQS_37
And (3) taking inertia effect into account in the primary frequency modulation process, and correcting the unbalanced regional power into:
Figure QLYQS_38
(9)
Figure QLYQS_39
(10)
in the method, in the process of the invention,
Figure QLYQS_40
unbalanced power for a regional power system;
s323, forward difference of the transfer function is obtained:
Figure QLYQS_41
(11)
in the method, in the process of the invention,
Figure QLYQS_42
is->
Figure QLYQS_43
Frequency deviation of time,/->
Figure QLYQS_44
Fitting for Quantum particle swarm Algorithm +.>
Figure QLYQS_45
Time zone power system unbalanced power, +.>
Figure QLYQS_46
Fitting for Quantum particle swarm Algorithm +.>
Figure QLYQS_47
Unbalanced power of the power system in the time zone;
s324, estimating an adaptability function of an equivalent difference adjustment coefficient of the regional power system, wherein the adaptability function is shown in the following formula:
Figure QLYQS_48
(12)
in the method, in the process of the invention,
Figure QLYQS_49
to characterize the fitness function of the power curve fitting effect, +.>
Figure QLYQS_50
Unbalanced power of a regional power system fitted for a quantum particle swarm algorithm;
and S4, evaluating inertia and primary frequency modulation capacity of the whole power system by carrying out weighted aggregation on the equivalent inertia time constant and the equivalent difference modulation coefficient of each region.
2. The QPSO-based power system inertia and primary frequency modulation capability assessment method according to claim 1, wherein: the step S2 specifically comprises the following steps:
based on Euclidean distance and K-means algorithm, the collected power plant grid-connected busbar frequency time series are clustered, the frequency time series and the cluster center closest to the frequency time series are classified, and the power system is divided into a plurality of areas by combining the power grid topology.
3. The QPSO-based power system inertia and primary frequency modulation capability assessment method according to claim 2, wherein: the step S2 specifically comprises the following steps:
s21, measuring the frequency discrete time sequence of the node A through the PMU
Figure QLYQS_51
And frequency discrete time sequence of node B +.>
Figure QLYQS_52
For frequency discrete time series +.>
Figure QLYQS_53
And->
Figure QLYQS_54
Satisfy->
Figure QLYQS_55
Figure QLYQS_56
,/>
Figure QLYQS_57
Is the length of the frequency discrete time series;
s22, representing the similarity between time sequences of different frequencies by using Euclidean distance, wherein the distance index is shown as follows:
Figure QLYQS_58
(1)
in the method, in the process of the invention,
Figure QLYQS_59
for frequency time series->
Figure QLYQS_60
And->
Figure QLYQS_61
A Euclidean distance between them;
s23, clustering the frequencies by adopting a K-means algorithm based on the defined Euclidean distance index;
s24, dividing the power system into a plurality of areas by combining the power grid topology.
4. The QPSO-based power system inertia and primary frequency modulation capability assessment method according to claim 3, wherein: the step S23 specifically includes the following steps:
s231, designating the cluster number M, and calculating the distance between the sample and the cluster center assuming that each cluster has a center point:
Figure QLYQS_62
(2)
in the method, in the process of the invention,
Figure QLYQS_63
for the frequency-time series of acquisition, +.>
Figure QLYQS_64
For the center point vector of the cluster where the sample is located, the sample and the nearest center point are divided into a cluster, +.>
Figure QLYQS_65
For calculating the distance between two frequency time sequences, < >>
Figure QLYQS_66
For the length of the frequency discrete time series, +.>
Figure QLYQS_67
Is the distance between the sample and the cluster center;
s232, randomly selecting M points as center points of each cluster, and iteratively executing the following two steps:
finding respective sample data for each center point, and dividing the sample data into center points closest to each center point;
and (3) recalculating the center point in each cluster, wherein the new center point is the arithmetic average value of members in the cluster, so that the calculated L value of the new center point is necessarily smaller than or equal to the original L value, and the iterative loop is carried out until the clustering algorithm converges and then exits.
5. The QPSO-based power system inertia and primary frequency modulation capability assessment method according to claim 1, wherein: the step S33 specifically includes the following steps:
s331, determining dimension of quantum particle swarm target search space
Figure QLYQS_68
I.e. the number of decision variables to be solved; at this time, assume thatNThe particles form a group, and the movement of each particle not only needs to consider the optimal position searched by the particle, but also comprehensively considers the optimal position searched by the group; in quantum space, the velocity and position of the particles cannot be determined simultaneously, so the wavefunction +.>
Figure QLYQS_69
Describing the state of the particle, wherein->
Figure QLYQS_70
Is a position vector of a particle in a three-dimensional space, and the probability density of the occurrence of the particle at a certain point in the space is represented by the square of a wave function modulus, namely:
Figure QLYQS_71
(13)
wherein Q is a probability density function that satisfies a normalization condition:
Figure QLYQS_72
(14)
s332, describing the movement of particles in quantum mechanics by a Schrodinger equation:
Figure QLYQS_73
(15)
Figure QLYQS_74
(16)
wherein, the liquid crystal display device comprises a liquid crystal display device,
Figure QLYQS_75
is Manhattan operator,)>
Figure QLYQS_76
Is Planck constant, +.>
Figure QLYQS_77
For particle quality, < >>
Figure QLYQS_78
Is the potential field where the particles are located;
s333, consider a single particle
Figure QLYQS_79
The point is one-dimensional +.>
Figure QLYQS_80
Motion in the potential well, attractor of particles +.>
Figure QLYQS_81
Marked as->
Figure QLYQS_82
The position of the particles is marked->
Figure QLYQS_83
The potential energy function is as follows:
Figure QLYQS_84
(17)
in the method, in the process of the invention,
Figure QLYQS_85
is Euler-Ma Xieluo Niconstant;
s334, determining the position of the particles by adopting a Monte Carlo method:
Figure QLYQS_86
(18)
Figure QLYQS_87
(19)
wherein, the liquid crystal display device comprises a liquid crystal display device,
Figure QLYQS_88
is->
Figure QLYQS_89
Characteristic length of potential well->
Figure QLYQS_90
Is section->
Figure QLYQS_91
On uniformly distributed random numbers, i.e. +.>
Figure QLYQS_92
The particles are
Figure QLYQS_93
First->
Figure QLYQS_94
The basic evolution equation for the coordinates of the dimensions is:
Figure QLYQS_95
(20)
in the method, in the process of the invention,
Figure QLYQS_97
for the time t+1 particle->
Figure QLYQS_101
First->
Figure QLYQS_104
Coordinates of dimension->
Figure QLYQS_99
For time t particle->
Figure QLYQS_102
First->
Figure QLYQS_105
Attractor for vitamin, jersey>
Figure QLYQS_106
For time t particle->
Figure QLYQS_96
First->
Figure QLYQS_100
Wei->
Figure QLYQS_103
Characteristic length of potential well->
Figure QLYQS_107
For time interval t->
Figure QLYQS_98
Random numbers uniformly distributed on the base;
s335, introducing an average best position
Figure QLYQS_108
Defined as the average of the best positions of all particle individuals,/->
Figure QLYQS_109
By passing through
Figure QLYQS_110
To evaluate, the evolution equation of the particles is rewritten as:
Figure QLYQS_111
(21)
Figure QLYQS_112
(22)
wherein, the liquid crystal display device comprises a liquid crystal display device,
Figure QLYQS_113
for the contraction-expansion coefficient, +.>
Figure QLYQS_114
For time t particle->
Figure QLYQS_115
First->
Figure QLYQS_116
Coordinates of dimension->
Figure QLYQS_117
For the number of particle populations,
Figure QLYQS_118
is->
Figure QLYQS_119
The best position is averaged.
6. The QPSO-based power system inertia and primary frequency modulation capability assessment method according to claim 1, wherein: the step S4 specifically comprises the following steps:
setting reference capacity of the power system, aggregating evaluation results of inertia and primary frequency modulation capacity of each area, and calculating equivalent inertia time constant and equivalent difference adjustment coefficient of the power system on line.
7. The QPSO-based power system inertia and primary frequency modulation capability assessment method of claim 6, wherein the method is characterized by: the step S4 specifically comprises the following steps:
dividing an electrical power system into
Figure QLYQS_120
Setting rated capacity of the system, aggregating evaluation results of inertia and primary frequency modulation capacity of each region, and calculating equivalent inertia time constant and equivalent difference adjustment coefficient of the power system on line;
wherein, the equivalent inertia of the power system is expressed as:
Figure QLYQS_121
(23)
in the method, in the process of the invention,
Figure QLYQS_122
for the equivalent inertia of the power system->
Figure QLYQS_123
For the kinetic energy stored by all generators in the area, +.>
Figure QLYQS_124
Equivalent inertial time constant for each region, +.>
Figure QLYQS_125
Rated capacity for each zone;
the system equivalent inertial time constant is represented by a weighted average of the equivalent inertial time constants of the respective regions:
Figure QLYQS_126
(24)
wherein, the liquid crystal display device comprises a liquid crystal display device,
Figure QLYQS_127
is the equivalent inertia time constant of the electric power system, +.>
Figure QLYQS_128
Is a reference capacity of the power system;
likewise, the power system equivalent difference coefficient is represented by a weighted average of the regional equivalent difference coefficients:
Figure QLYQS_129
(25)
in the method, in the process of the invention,
Figure QLYQS_130
is the equivalent difference adjustment coefficient of the power system, +.>
Figure QLYQS_131
Is the equivalent difference adjustment coefficient of each region.
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