CN108418242B - Doubly-fed wind turbine dynamic equivalence method based on similarity coherence - Google Patents

Doubly-fed wind turbine dynamic equivalence method based on similarity coherence Download PDF

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CN108418242B
CN108418242B CN201810064146.0A CN201810064146A CN108418242B CN 108418242 B CN108418242 B CN 108418242B CN 201810064146 A CN201810064146 A CN 201810064146A CN 108418242 B CN108418242 B CN 108418242B
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朱林
王贝
陈达
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South China University of Technology SCUT
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Abstract

The invention discloses a dynamic equivalence method of a doubly-fed wind turbine based on similarity coherence, which comprises the following steps: step S10, fitting the output power of the doubly-fed wind motor into a linear combination of exponential functions of amplitude, phase, frequency and damping by using a prony algorithm; step S20, determining a similar oscillation mode between the doubly-fed wind motors by using a similar theory according to the linear combination obtained in the step S10; step S30, defining a similarity quantization index of the homodyne similarity between the double-fed wind turbines by using a similar oscillation mode, and judging a homodyne group in the wind power plant; step S40, taking the active power output by the doubly-fed wind generator as weight to obtain equivalent transient internal potential of the equivalent machine, and connecting equivalent transient internal potential buses of the doubly-fed wind generator in the same group to equivalent transient internal potential buses of the equivalent machine through a complex transformation ratio phase-shifting transformer respectively; and S50, calculating equivalent parameters of each equivalent machine, and connecting the potential bus in the equivalent transient state of the equivalent machine to the equivalent machine through the impedance of the equivalent doubly-fed wind generator.

Description

Doubly-fed wind turbine dynamic equivalence method based on similarity coherence
Technical Field
The invention relates to the technical field of equivalent modeling of a wind power plant in a new energy power generation technology, in particular to a dynamic equivalent method of a double-fed wind power machine based on similarity coherence.
Background
With the rapid development of the modern power industry, large-scale alternating current and direct current interconnected power systems appear, the characteristics of multiple machines (thousands of machines) and large power grids (thousands of lines and thousands of buses) are more and more prominent, and the calculation of the planning design and the operation mode of the power systems becomes extremely complicated. On the one hand, it takes a lot of time and space to perform these calculations in detail, and on the other hand, they are difficult to implement in practice due to the limitations of the simulation scale and hardware equipment. For this reason, some reasonable simplification of the original system is required, thereby reducing the system scale. In practice, dynamic performance research on a large power system is generally most interested in a certain area, which is called a research system, and the area far away from the area is not required to be described in detail as long as the influence of the dynamic performance research on the research area is taken into consideration, so that the order and the simplification can be performed to save manpower and material resources for research, and the area to be simplified is called an external system. It is necessary to simplify the equivalence of external systems that do not require detailed analysis.
Wind power is a new energy with the most development potential and large-scale development, and has received wide attention from all countries in the world since the 70 s in the 20 th century. With the rapid development of wind power, wind power plants have explosive growth in scale and number, and therefore the influence of large-scale wind power plant grid connection on a power system is increased day by day. When the influence of large-scale wind power access on the dynamic characteristics of a power system is researched, a wind power plant model capable of accurately representing the overall dynamic characteristics of a wind power plant is needed. The wind power plant is generally composed of dozens of or even hundreds of wind power units, wherein the model of each double-fed wind power unit reaches dozens of orders, and the efficiency of modeling and simulating the wind power plant by adopting a detailed model is very low, so that the simplified aggregate modeling of the large-scale wind power plant is necessary.
At present, in a large power grid, the value of a network is generally equal to that of a higher voltage level, and the value of a wind power plant at a lower voltage level is equal to that of a load with negative active power, so that the dynamic characteristic of the wind power plant is omitted. With the rapid development of wind power technology, the capacity of a single machine reaches megawatt level, the proportion of the wind power generation capacity in the total power generation capacity of a power grid is larger and larger, the influence of the dynamic characteristics on the operation characteristics of the power grid is increasingly remarkable, and when dynamic equivalence is carried out, the characteristics of a region where a wind power plant is concentrated cannot be simply ignored any more, so that an equivalence simplification method of the wind power plant is urgently needed to be deeply researched.
Clustering and parameter aggregation are important contents of wind power plant dynamic equivalence. At present, related documents for judging the wind power plant coherence characteristics are few, and related documents propose a method for clustering according to characteristic quantity coherence, but the method has the problem of complete selection of the characteristic quantity, and whether universality exists in the method is a bottleneck which hinders the application of the method. The similarity grouping based on disturbed trajectory is a common method for grouping multiple machine systems, the power angle of a generator is often used as an observed quantity, and different from a synchronous motor, the difference between the external dynamic characteristic of a double-fed fan and the traditional synchronous generator is larger due to the existence of power electronic equipment, so that no consensus is formed for comparing disturbed trajectories of adopted variables when the wind motors are identified in the process of carrying out coherence. In addition, because the double-fed wind turbine adopts decoupling control, inertia is not reflected to the outside, the influence of the double-fed wind turbine on a system is only represented by the amount of generated power, and related documents for the method research of wind turbine parameter aggregation are few at present. Therefore, a dynamic equivalence method suitable for coherence judgment and parameter aggregation of a wind power plant is urgently needed to meet the dynamic equivalence requirement of a power system containing a large-scale wind power plant.
Disclosure of Invention
The invention aims to provide a dynamic equivalence method of a doubly-fed wind turbine based on similarity coherence, aiming at the defects of the prior art, so as to realize the accurate division of a homodyne group of the doubly-fed wind turbine and the reasonable aggregation of dynamic parameters in the equivalent modeling process of a wind power plant, greatly reduce the scale of the wind turbine and keep the dynamic characteristics of the wind turbine.
The purpose of the invention can be realized by the following technical scheme:
a doubly-fed wind turbine dynamic equivalence method based on similarity coherence comprises the following steps:
step S10, fitting the output power of the doubly-fed wind motor into a linear combination of exponential functions of amplitude, phase, frequency and damping by using a prony algorithm;
step S20, determining a similar oscillation mode between the doubly-fed wind motors by using a similar theory according to the linear combination obtained in the step S10;
step S30, defining a similarity quantization index of the homodyne similarity between the double-fed wind turbines by using a similar oscillation mode, and judging a homodyne group in the wind power plant;
step S40, taking the active power output by the doubly-fed wind generator as weight to obtain equivalent transient internal potential of the equivalent machine, and connecting equivalent transient internal potential buses of the doubly-fed wind generator in the same group to equivalent transient internal potential buses of the equivalent machine through a complex transformation ratio phase-shifting transformer respectively;
and S50, calculating equivalent parameters of each equivalent machine, and connecting the potential bus in the equivalent transient state of the equivalent machine to the equivalent machine through the impedance of the equivalent doubly-fed wind generator.
Further, the linear combination formula obtained in step S10 is as follows:
Figure BDA0001556217840000021
wherein the content of the first and second substances,
Figure BDA0001556217840000031
represents an approximation of X (n), bi＝Aiexp(jθi)，Zi＝exp((αi+j2πfi)Δt)，AiAmplitude, θ, representing output power of doubly-fed wind turbineiInitial phase angle f representing output power of doubly-fed wind generatoriα indicating the oscillation frequency of the doubly-fed wind turbine outputiFor the attenuation factor of the oscillation frequency, Δ t represents the sampling interval, p represents the number of linear combinations of exponential functions of arbitrary amplitude, phase, frequency and damping, and J represents the order of the prony algorithm decomposition.
Further, the specific process of step S20 is: energy E of ith oscillation mode of output power of doubly-fed wind generatoriThe sum of the squares of the modulus values of the sampling points in the oscillation mode is obtained as follows:
Ei＝Aiexp(jθi)·exp(n·Δt·(αi+j2πfi)) (2)
wherein n is 0,1, and J-1, wherein J represents the order of prony algorithm decomposition;
setting an energy threshold v, wherein the value of the energy threshold v is higher than 99%, the specific value can be set according to the requirement of coherent precision, all oscillation modes are sequenced from high to low according to energy, and the energy is accumulated in sequence until the obtained energy is not less than the total energy
Figure BDA0001556217840000032
Product with energy threshold v:
Figure BDA0001556217840000033
after redundant items in the before-after-equivalence oscillation mode are eliminated by the method, an before-equivalence l-order oscillation mode containing most information can be obtained, wherein l is far smaller than the order J of prony algorithm decomposition, and the searching process of the similar oscillation mode is simplified;
according to the principle that the Euclidean distance among frequency, damping and energy in characteristic information is minimum, an l-order oscillation mode of an output power curve of one doubly-fed wind generator is used as a reference, similar oscillation modes are searched in m-order oscillation modes of output power curves of other doubly-fed wind generators, and for the conditions that i is 1,2, …, l and k are 1,2, … and m, calculation is carried out:
Figure BDA0001556217840000034
wherein f isAiFrequency f representing ith oscillation mode of output power curve of reference doubly-fed wind generatorBkRepresenting the frequency of the kth oscillation mode of the output power curve of other doubly-fed wind turbines, αAiDenotes fAiαBkDenotes fBkAttenuation factor of, EAiRepresenting the energy of the ith oscillation mode of the output power curve of the reference doubly-fed wind turbine, EBkRepresenting the energy of the kth oscillation mode of the output power curve of other doubly-fed wind motors, and calculating to obtain the minimum d for the oscillation mode iikAnd the reference doubly-fed wind generator output power curve oscillation mode i and the other doubly-fed wind generator output power curve oscillation modes k are a pair of similar oscillation modes, the oscillation mode k is removed from the oscillation modes, the oscillation modes are used for the searching process of the next pair of similar oscillation modes, and finally the pair of similar oscillation modes is obtained.
Further, the specific process of step S30 is: obtaining the frequency similarity q (f) between the ith similar oscillation modes after the l-order similar oscillation modes of the doubly-fed wind turbines are obtained according to the step S20i) And damping similarity q (α)i) Respectively as follows:
Figure BDA0001556217840000041
Figure BDA0001556217840000042
wherein f isAiFrequency f representing ith oscillation mode of output power curve of reference doubly-fed wind generatorBiRepresenting the frequency of the ith oscillation mode of the output power curve of other doubly-fed wind turbines, αAiDenotes fAiαBiDenotes fBiConsidering the similarity weight of frequency and damping, the similarity between the ith similar oscillation mode is:
Figure BDA0001556217840000043
wherein a and b represent similarity weights of frequency and damping, respectively;
the ratio of the energy of each partial mode in the oscillation mode to the total energy is taken as the weight of the partial mode energy accounting for the energy of all the oscillation modes in the similarity calculation:
Figure BDA0001556217840000044
the similarity of all similar oscillation modes after considering the energy weight is as follows:
Figure BDA0001556217840000045
wherein EiAnd representing the energy of the ith oscillation mode of the output power of the doubly-fed wind motor, and determining a coherent group in the wind power plant after calculating a coherent similarity quantization index between the doubly-fed wind motors.
Further, the specific process of step S40 is: firstly, the voltage equations of the stator and the rotor of each doubly-fed wind turbine are expressed as follows:
Figure BDA0001556217840000046
wherein u, i and psi respectively represent the voltage, current and flux linkage of the doubly-fed wind motor; r, L represent the resistance and inductance of the doubly-fed wind machine, respectively; s and r in subscripts respectively represent a stator and a rotor of the doubly-fed wind motor; d and q in subscripts respectively represent a direct axis component and a quadrature axis component; l ismRepresenting the mutual inductance of the doubly-fed wind generator; p is a differential operator; s represents slip;
in the formula (I), the compound is shown in the specification,
Figure BDA0001556217840000051
order:
Figure BDA0001556217840000052
wherein, Xss＞＞RsTherefore, the stator voltage drop of the doubly-fed wind generator can be ignored, and the equivalent transient internal potential of the doubly-fed wind generator is defined as follows:
E'＝Us-jXssIs(12)
wherein, UsRepresenting terminal voltage, I, of doubly-fed wind generatorsRepresenting the stator current of the doubly-fed wind generator, j represents a symbol with phase lead of 90 degrees;
because the doubly-fed wind motor adopts decoupling control, inertia is not reflected to the outside, the influence of the doubly-fed wind motor on a system is represented only by injected power, a polymerization method taking output power as weight is adopted, the number of the doubly-fed wind motors in a coherent group is set to be N, and the equivalent transient internal potential of an equivalent machine is set to be N
Figure BDA0001556217840000053
Comprises the following steps:
Figure BDA0001556217840000054
wherein p isiThe active power of the ith doubly-fed wind generator in the coherent cluster is represented; the equivalent transient internal potential of the equivalent machine is determined by all the double-fed wind motors in the coherent machine group, and the weight occupied by each double-fed wind motor depends on the output power of the double-fed wind motor according to the external characteristics of the double-fed wind motors;
the transformation ratio of the complex transformation ratio phase-shifting transformer is as follows:
Figure BDA0001556217840000055
Figure BDA0001556217840000056
and representing the equivalent transient internal potential of the ith doubly-fed wind generator in the coherent group, and connecting equivalent transient internal potential buses of the doubly-fed wind generators in the coherent group to equivalent transient internal potential buses of the equivalent machine through a complex transformation ratio phase-shifting transformer respectively.
Further, in step S50, the equivalent parameters of each equivalence machine are:
Figure BDA0001556217840000061
wherein N represents the number of the double-fed wind motors in the coherent cluster, P represents the active power of the double-fed wind motors, Q represents the reactive power of the double-fed wind motors, and X representssRepresenting the stator reactance, X, of a doubly-fed wind machinerRepresenting the rotor reactance of a doubly-fed wind machine, HgRepresenting the rotor inertia time constant, H, of an inductive generator in a doubly-fed wind generatortRepresenting the rotor inertia time constant, K, of a wind turbine in a doubly-fed wind turbinesAnd representing the shafting stiffness coefficient of a wind turbine in the doubly-fed wind turbine, wherein eq in the subscript respectively represents equivalent machine parameters.
Compared with the prior art, the invention has the following advantages and beneficial effects:
1. the similarity-coherence-based dynamic equivalence method for the doubly-fed wind turbine can effectively divide coherence groups of the large-scale doubly-fed wind turbine and perform reasonable parameter aggregation on coherence groups. The method can remarkably reduce the scale of the wind turbine generator on the premise of keeping the dynamic characteristic of the wind turbine generator, thereby simplifying the external area and highlighting the area to be researched which is focused. The method comprises the steps of firstly, fitting output power of a wind power plant into linear combination of exponential functions of amplitude, phase, frequency and damping by using a prony algorithm, then determining a similar oscillation mode by using a similar theory, defining a quantification index of the coherent similarity between wind power plants by using the similar oscillation mode, and judging coherent units in the wind power plant; then, taking the active power output by the doubly-fed wind generator as a weight to obtain the equivalent transient internal potential of the equivalent machine, and connecting the transient internal potential buses of the doubly-fed wind generator in the same group to the equivalent transient internal potential buses through a complex transformation ratio phase-shifting transformer respectively; and finally, calculating equivalent parameters of each equivalent unit, and connecting the equivalent transient internal potential to the equivalent machine through the impedance of the equivalent doubly-fed wind generator. Therefore, the high-precision equivalence simplification requirements of a large power grid containing large-scale wind turbine generators are met, the aggregation method can better reflect the real dynamic characteristics of the wind power plant, and a foundation is laid for scientifically and correctly analyzing the influence of large-scale wind power plant grid connection on the dynamic characteristics of the large power grid.
2. The dynamic equivalence method of the doubly-fed wind turbine based on similarity coherence carries out dynamic equivalence on the wind power plant, can greatly reduce the scale of the wind turbine and reserve the power characteristic of the wind turbine, and can better reflect the real characteristic of the wind power plant after equivalence, thereby meeting the high-precision equivalence simplification requirement of a large power grid containing large-scale wind turbines.
Drawings
Fig. 1 is a flowchart of a dynamic equivalence method of a doubly-fed wind turbine based on similarity coherence in an embodiment of the present invention.
FIG. 2 is a diagram illustrating steps for constructing an equivalence machine according to an embodiment of the invention.
Detailed Description
The present invention will be described in further detail with reference to examples and drawings, but the present invention is not limited thereto.
Example (b):
the embodiment provides a dynamic equivalence method of a doubly-fed wind turbine based on similarity coherence, and a flow chart of the method is shown in fig. 1, and the method comprises the following steps:
step S10, fitting an output power characteristic curve of the doubly-fed wind motor into a linear combination of exponential functions of amplitude, phase, frequency and damping by utilizing a prony algorithm; the linear combination formula is as follows:
Figure BDA0001556217840000071
wherein the content of the first and second substances,
Figure BDA0001556217840000072
represents an approximation of X (n), bi＝Aiexp(jθi)，Zi＝exp((αi+j2πfi)Δt)，AiAmplitude, θ, representing output power of doubly-fed wind turbineiInitial phase angle f representing output power of doubly-fed wind generatoriα indicating the oscillation frequency of the doubly-fed wind turbine outputiThe attenuation factor of the oscillation frequency, delta t represents the sampling interval, p represents the number of linear combinations of exponential functions of any amplitude, phase, frequency and damping, and J represents the order of prony algorithm decomposition;
step S20, determining a similar oscillation mode between the doubly-fed wind motors by using a similar theory according to the linear combination obtained in the step S10; the specific process is as follows: energy E of ith oscillation mode of output power of doubly-fed wind generatoriThe sum of the squares of the modulus values of the sampling points in the oscillation mode is obtained as follows:
Ei＝Aiexp(jθi)·exp(n·Δt·(αi+j2πfi)) (2)
wherein n is 0,1, and J-1, wherein J represents the order of prony algorithm decomposition;
setting an energy threshold value v, wherein the value of the energy threshold value v should be higher than 99%, the specific value can be set according to the requirement of coherent precision, the value of the energy threshold value v is set to be 99.9%, all oscillation modes are ranked from high to low according to energy, and are sequentially accumulated until the obtained energy is not less than the total energy
Figure BDA0001556217840000073
Product with energy threshold v:
Figure BDA0001556217840000074
after redundant items in the before-after-equivalence oscillation mode are eliminated by the method, an before-equivalence l-order oscillation mode containing most information can be obtained, wherein l is far smaller than the order J of prony algorithm decomposition, and the searching process of the similar oscillation mode is simplified;
according to the principle that the Euclidean distance among frequency, damping and energy in characteristic information is minimum, an l-order oscillation mode of an output power curve of one doubly-fed wind generator is used as a reference, similar oscillation modes are searched in m-order oscillation modes of output power curves of other doubly-fed wind generators, and for the conditions that i is 1,2, …, l and k are 1,2, … and m, calculation is carried out:
Figure BDA0001556217840000081
wherein f isAiFrequency f representing ith oscillation mode of output power curve of reference doubly-fed wind generatorBkRepresenting the frequency of the kth oscillation mode of the output power curve of other doubly-fed wind turbines, αAiDenotes fAiαBkDenotes fBkAttenuation factor of, EAiRepresenting the energy of the ith oscillation mode of the output power curve of the reference doubly-fed wind turbine, EBkRepresenting the energy of the kth oscillation mode of the output power curve of other doubly-fed wind motors, and calculating to obtain the minimum d for the oscillation mode iikAnd the reference doubly-fed wind generator output power curve oscillation mode i and the other doubly-fed wind generator output power curve oscillation modes k are a pair of similar oscillation modes, the oscillation mode k is removed from the oscillation modes, the oscillation modes are used for the searching process of the next pair of similar oscillation modes, and finally the pair of similar oscillation modes is obtained.
Step S30, defining a similarity quantization index of the homodyne similarity between the double-fed wind turbines by using a similar oscillation mode, and judging a homodyne group in the wind power plant; the specific process is as follows: obtaining each double feed according to step S20Frequency similarity q (f) between ith similar oscillation modes after l-order similar oscillation modes of wind turbinei) And damping similarity q (α)i) Respectively as follows:
Figure BDA0001556217840000082
Figure BDA0001556217840000083
wherein f isAiFrequency f representing ith oscillation mode of output power curve of reference doubly-fed wind generatorBiRepresenting the frequency of the ith oscillation mode of the output power curve of other doubly-fed wind turbines, αAiDenotes fAiαBiDenotes fBiConsidering the similarity weight of frequency and damping, the similarity between the ith similar oscillation mode is:
Figure BDA0001556217840000084
wherein a and b respectively represent similarity weights of frequency and damping, and the similarity weights of the frequency and the damping are considered to be equal, so that the similarity between the ith similar oscillation mode is obtained as follows:
q(λi)＝0.5q(fi)+0.5q(αi)
the ratio of the energy of each partial mode in the oscillation mode to the total energy is taken as the weight of the partial mode energy accounting for the energy of all the oscillation modes in the similarity calculation:
Figure BDA0001556217840000091
the similarity of all similar oscillation modes after considering the energy weight is as follows:
Figure BDA0001556217840000092
wherein EiAnd representing the energy of the ith oscillation mode of the output power of the doubly-fed wind motor, and determining a coherent group in the wind power plant after calculating a coherent similarity quantization index between the doubly-fed wind motors.
Step S40, taking the active power output by the doubly-fed wind generator as weight to obtain equivalent transient internal potential of the equivalent machine, and connecting equivalent transient internal potential buses of the doubly-fed wind generator in the same group to equivalent transient internal potential buses of the equivalent machine through a complex transformation ratio phase-shifting transformer respectively; the specific process is as follows: firstly, the voltage equations of the stator and the rotor of each doubly-fed wind turbine are expressed as follows:
Figure BDA0001556217840000093
wherein u, i and psi respectively represent the voltage, current and flux linkage of the doubly-fed wind motor; r, L represent the resistance and inductance of the doubly-fed wind machine, respectively; s and r in subscripts respectively represent a stator and a rotor of the doubly-fed wind motor; d and q in subscripts respectively represent a direct axis component and a quadrature axis component; l ismRepresenting the mutual inductance of the doubly-fed wind generator; p is a differential operator; s represents slip;
in the formula (I), the compound is shown in the specification,
Figure BDA0001556217840000094
order:
Figure BDA0001556217840000095
wherein, Xss＞＞RsTherefore, the stator voltage drop of the doubly-fed wind generator can be ignored, and the equivalent transient internal potential of the doubly-fed wind generator is defined as follows:
E'＝Us-jXssIs(12)
wherein, UsRepresenting terminal voltage, I, of doubly-fed wind generatorsRepresenting the stator current of the doubly-fed wind generator, j represents a symbol with phase lead of 90 degrees;
because the double-fed wind motor adopts decoupling control, inertia is not reflected to the outside, and the double-fed wind motor only influences a system throughThe injected power is characterized, an aggregation method taking output power as weight is adopted, the number of doubly-fed wind motors in a coherent cluster is set to be N, the construction flow of an equivalent machine is shown in figure 2, and the equivalent transient internal potential of the equivalent machine
Figure BDA0001556217840000101
Comprises the following steps:
Figure BDA0001556217840000102
wherein p isiThe active power of the ith doubly-fed wind generator in the coherent cluster is represented; the equivalent transient internal potential of the equivalent machine is determined by all the double-fed wind motors in the coherent machine group, and the weight occupied by each double-fed wind motor depends on the output power of the double-fed wind motor according to the external characteristics of the double-fed wind motors;
the transformation ratio of the complex transformation ratio phase-shifting transformer is as follows:
Figure BDA0001556217840000103
Figure BDA0001556217840000104
representing the equivalent transient internal potential of the ith doubly-fed wind generator in the coherent cluster, and respectively connecting equivalent transient internal potential buses of the doubly-fed wind generators in the coherent cluster to equivalent transient internal potential buses of an equivalent machine through a complex transformation ratio phase-shifting transformer;
step S50, calculating equivalent parameters of each equivalent machine, and connecting the potential bus in the equivalent transient state of the equivalent machine to the equivalent machine through the impedance of the equivalent doubly-fed wind generator, wherein the equivalent parameters of each equivalent machine are as follows:
Figure BDA0001556217840000105
wherein N represents the number of the double-fed wind motors in the coherent cluster, P represents the active power of the double-fed wind motors, Q represents the reactive power of the double-fed wind motors, and X representssStator for double-fed wind generatorReactance, XrRepresenting the rotor reactance of a doubly-fed wind machine, HgRepresenting the rotor inertia time constant, H, of an inductive generator in a doubly-fed wind generatortRepresenting the rotor inertia time constant, K, of a wind turbine in a doubly-fed wind turbinesAnd representing the shafting stiffness coefficient of a wind turbine in the doubly-fed wind turbine, wherein eq in the subscript respectively represents equivalent machine parameters.
The above description is only for the preferred embodiments of the present invention, but the protection scope of the present invention is not limited thereto, and any person skilled in the art can substitute or change the technical solution of the present invention and the inventive concept within the scope of the present invention, which is disclosed by the present invention, and the equivalent or change thereof belongs to the protection scope of the present invention.

Claims (5)

1. A doubly-fed wind turbine dynamic equivalence method based on similarity coherence is characterized by comprising the following steps:
step S10, fitting the output power of the doubly-fed wind motor into a linear combination of exponential functions of amplitude, phase, frequency and damping by using a prony algorithm;
step S20, determining a similar oscillation mode between the doubly-fed wind motors by using a similar theory according to the linear combination obtained in the step S10;
step S30, defining a similarity quantization index of the homodyne similarity between the double-fed wind turbines by using a similar oscillation mode, and judging a homodyne group in the wind power plant;
step S40, taking the active power output by the doubly-fed wind generator as weight to obtain equivalent transient internal potential of the equivalent machine, and connecting equivalent transient internal potential buses of the doubly-fed wind generator in the same group to equivalent transient internal potential buses of the equivalent machine through a complex transformation ratio phase-shifting transformer respectively;
the specific process of step S40 is: firstly, the voltage equations of the stator and the rotor of each doubly-fed wind turbine are expressed as follows:
Figure FDA0002424744400000011
wherein u, i, ψRespectively representing the voltage, the current and the flux linkage of the doubly-fed wind motor; r, L represent the resistance and inductance of the doubly-fed wind machine, respectively; s and r in subscripts respectively represent a stator and a rotor of the doubly-fed wind motor; d and q in subscripts respectively represent a direct axis component and a quadrature axis component; l ismRepresenting the mutual inductance of the doubly-fed wind generator; p is a differential operator;
in the formula (I), the compound is shown in the specification,
Figure FDA0002424744400000012
order:
Figure FDA0002424744400000013
wherein, Xss＞＞RsTherefore, the stator voltage drop of the doubly-fed wind generator can be ignored, and the equivalent transient internal potential of the doubly-fed wind generator is defined as follows:
E'＝Us-jXssIs(12)
wherein, UsRepresenting terminal voltage, I, of doubly-fed wind generatorsRepresenting the stator current of the doubly-fed wind generator, j represents a symbol with phase lead of 90 degrees;
because the doubly-fed wind motor adopts decoupling control, inertia is not reflected to the outside, the influence of the doubly-fed wind motor on a system is represented only by injected power, a polymerization method taking output power as weight is adopted, the number of the doubly-fed wind motors in a coherent group is set to be N, and the equivalent transient internal potential of an equivalent machine is set to be N
Figure FDA0002424744400000021
Comprises the following steps:
Figure FDA0002424744400000022
wherein p isiThe active power of the ith doubly-fed wind generator in the coherent cluster is represented; the equivalent transient internal potential of the equivalent machine is determined by all the double-fed wind motors in the coherent machine group, and the weight occupied by each double-fed wind motor depends on the double-fed wind motor according to the external characteristics of the double-fed wind motorsThe output power of the same;
the transformation ratio of the complex transformation ratio phase-shifting transformer is as follows:
Figure FDA0002424744400000023
Figure FDA0002424744400000024
representing the equivalent transient internal potential of the ith doubly-fed wind generator in the coherent cluster, and respectively connecting equivalent transient internal potential buses of the doubly-fed wind generators in the coherent cluster to equivalent transient internal potential buses of an equivalent machine through a complex transformation ratio phase-shifting transformer;
and S50, calculating equivalent parameters of each equivalent machine, and connecting the potential bus in the equivalent transient state of the equivalent machine to the equivalent machine through the impedance of the equivalent doubly-fed wind generator.
2. The dynamic equivalence method for the doubly-fed wind turbine based on similarity coherence of claim 1, wherein the linear combination formula obtained in step S10 is as follows:
Figure FDA0002424744400000025
wherein the content of the first and second substances,
Figure FDA0002424744400000026
represents an approximation of X (n), bi＝Aiexp(jθi)，Zi＝exp((αi+j2πfi)Δt)，AiAmplitude, θ, representing output power of doubly-fed wind turbineiInitial phase angle f representing output power of doubly-fed wind generatoriα indicating the oscillation frequency of the doubly-fed wind turbine outputiFor the attenuation factor of the oscillation frequency, Δ t represents the sampling interval, p represents the number of linear combinations of exponential functions of arbitrary amplitude, phase, frequency and damping, and J represents the order of the prony algorithm decomposition.
3. The dynamic equivalence method for the doubly-fed wind turbine based on similarity coherence according to claim 1, wherein the specific process of the step S20 is as follows: energy E of ith oscillation mode of output power of doubly-fed wind generatoriThe sum of the squares of the modulus values of the sampling points in the oscillation mode is obtained as follows:
Ei＝Aiexp(jθi)·exp(n·Δt·(αi+j2πfi)) (2)
wherein n is 0,1, and J-1, wherein J represents the order of prony algorithm decomposition;
setting an energy threshold v, wherein the value of the energy threshold v is higher than 99%, the specific value can be set according to the requirement of coherent precision, all oscillation modes are sequenced from high to low according to energy, and the energy is accumulated in sequence until the obtained energy is not less than the total energy
Figure FDA0002424744400000031
Product with energy threshold v:
Figure FDA0002424744400000032
after redundant items in the before-after-equivalence oscillation mode are eliminated by the method, an before-equivalence l-order oscillation mode containing most information can be obtained, wherein l is far smaller than the order J of prony algorithm decomposition, and the searching process of the similar oscillation mode is simplified;
according to the principle that the Euclidean distance among frequency, damping and energy in characteristic information is minimum, an l-order oscillation mode of an output power curve of one doubly-fed wind generator is used as a reference, similar oscillation modes are searched in m-order oscillation modes of output power curves of other doubly-fed wind generators, and for the conditions that i is 1,2, …, l and k are 1,2, … and m, calculation is carried out:
Figure FDA0002424744400000033
wherein f isAiFrequency f representing ith oscillation mode of output power curve of reference doubly-fed wind generatorBkShow itFrequency of kth oscillation mode of output power curve of double-fed wind turbine, αAiDenotes fAiαBkDenotes fBkAttenuation factor of, EAiRepresenting the energy of the ith oscillation mode of the output power curve of the reference doubly-fed wind turbine, EBkRepresenting the energy of the kth oscillation mode of the output power curve of other doubly-fed wind motors, and calculating to obtain the minimum d for the oscillation mode iikAnd the reference doubly-fed wind generator output power curve oscillation mode i and the other doubly-fed wind generator output power curve oscillation modes k are a pair of similar oscillation modes, the oscillation mode k is removed from the oscillation modes, the oscillation modes are used for the searching process of the next pair of similar oscillation modes, and finally the pair of similar oscillation modes is obtained.
4. The dynamic equivalence method for the doubly-fed wind turbine based on similarity coherence according to claim 1, wherein the specific process of the step S30 is as follows: obtaining the frequency similarity q (f) between the ith similar oscillation modes after the l-order similar oscillation modes of the doubly-fed wind turbines are obtained according to the step S20i) And damping similarity q (α)i) Respectively as follows:
Figure FDA0002424744400000034
Figure FDA0002424744400000035
wherein f isAiFrequency f representing ith oscillation mode of output power curve of reference doubly-fed wind generatorBiRepresenting the frequency of the ith oscillation mode of the output power curve of other doubly-fed wind turbines, αAiDenotes fAiαBiDenotes fBiConsidering the similarity weight of frequency and damping, the similarity between the ith similar oscillation mode is:
Figure FDA0002424744400000041
wherein a and b represent similarity weights of frequency and damping, respectively;
the ratio of the energy of each partial mode in the oscillation mode to the total energy is taken as the weight of the partial mode energy accounting for the energy of all the oscillation modes in the similarity calculation:
Figure FDA0002424744400000042
the similarity of all similar oscillation modes after considering the energy weight is as follows:
Figure FDA0002424744400000043
wherein EiAnd representing the energy of the ith oscillation mode of the output power of the doubly-fed wind motor, and determining a coherent group in the wind power plant after calculating a coherent similarity quantization index between the doubly-fed wind motors.
5. The dynamic equivalence method for the doubly-fed wind turbine based on similarity coherence of claim 1, wherein in step S50, the equivalent parameters of each equivalence machine are as follows:
Figure FDA0002424744400000044
wherein N represents the number of the double-fed wind motors in the coherent cluster, P represents the active power of the double-fed wind motors, Q represents the reactive power of the double-fed wind motors, and X representssRepresenting the stator reactance, X, of a doubly-fed wind machinerRepresenting the rotor reactance of a doubly-fed wind machine, HgRepresenting the rotor inertia time constant, H, of an inductive generator in a doubly-fed wind generatortRepresenting the rotor inertia time constant, K, of a wind turbine in a doubly-fed wind turbinesAnd representing the shafting stiffness coefficient of a wind turbine in the doubly-fed wind turbine, wherein eq in the subscript respectively represents equivalent machine parameters.
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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101882167A (en) * 2009-11-25 2010-11-10 中国电力科学研究院 Wind power station equivalent modeling method of large-scale wind power concentration access power grid
CN102624309A (en) * 2012-03-29 2012-08-01 河海大学 Variable-speed double-fed wind power station clustering equating method based on mechanical and electrical dynamic characteristics
CN103887815A (en) * 2014-02-21 2014-06-25 华南理工大学 Wind power plant parameter identification and dynamic equivalence method based on operation data

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101882167A (en) * 2009-11-25 2010-11-10 中国电力科学研究院 Wind power station equivalent modeling method of large-scale wind power concentration access power grid
CN102624309A (en) * 2012-03-29 2012-08-01 河海大学 Variable-speed double-fed wind power station clustering equating method based on mechanical and electrical dynamic characteristics
CN103887815A (en) * 2014-02-21 2014-06-25 华南理工大学 Wind power plant parameter identification and dynamic equivalence method based on operation data

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
Aggregation of doubly-fed induction generator based wind farm considering storage device and coordinated control strategy;ZhenHua Xu等;《2011 International Conference on Advanced Power System Automation and Protection》;20120412;1013-1018页 *
双馈异步发电机风电场聚合模型研究;夏安俊，等;《电网技术》;20150731;第39卷(第7期);1879-1885页 *
基于相似理论的电力系统动态等值精确度量化评价方法;朱林，等;《电力科学与技术学报》;20161231;第31卷(第4期);116-122页 *

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