CN113946985B - Method and system for determining new energy station equivalent model - Google Patents

Method and system for determining new energy station equivalent model Download PDF

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CN113946985B
CN113946985B CN202111558333.2A CN202111558333A CN113946985B CN 113946985 B CN113946985 B CN 113946985B CN 202111558333 A CN202111558333 A CN 202111558333A CN 113946985 B CN113946985 B CN 113946985B
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equivalent
new energy
unit
station
model
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CN113946985A (en
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孙华东
李佳豪
郭强
李文锋
贾媛
王晖
杨超
魏巍
张健
陶向宇
艾东平
马世俊
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China Electric Power Research Institute Co Ltd CEPRI
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    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
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    • G06F30/00—Computer-aided design [CAD]
    • G06F30/20—Design optimisation, verification or simulation
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06Q—INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR ADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL OR SUPERVISORY PURPOSES; SYSTEMS OR METHODS SPECIALLY ADAPTED FOR ADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL OR SUPERVISORY PURPOSES, NOT OTHERWISE PROVIDED FOR
    • G06Q50/00—Systems or methods specially adapted for specific business sectors, e.g. utilities or tourism
    • G06Q50/06—Electricity, gas or water supply
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F2113/00—Details relating to the application field
    • G06F2113/04—Power grid distribution networks
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
    • Y02E40/70—Smart grids as climate change mitigation technology in the energy generation sector
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y04—INFORMATION OR COMMUNICATION TECHNOLOGIES HAVING AN IMPACT ON OTHER TECHNOLOGY AREAS
    • Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
    • Y04S10/00—Systems supporting electrical power generation, transmission or distribution
    • Y04S10/50—Systems or methods supporting the power network operation or management, involving a certain degree of interaction with the load-side end user applications

Abstract

The invention discloses a method and a system for determining an equivalent model of a new energy station, which comprise the following steps: acquiring a first new energy station equivalent model; constructing an equivalent model of the target new energy station based on the first new energy station equivalent model, and determining a second new energy station equivalent model; when the number of the first equivalent units considering the power distribution characteristics is a first preset threshold value, determining a power distribution value of each first equivalent unit; when the number of the second equivalent units considering the voltage distribution characteristics is a first preset threshold value, performing near-far grouping on the second equivalent units, and determining the impedance of each second equivalent unit; and determining operation parameter values of an equivalent unit and an equivalent transformer in the equivalent model of the second new energy station according to the operation data of the target new energy station, and performing parameter configuration on the equivalent model of the second new energy station based on the power distribution value, the impedance and the operation parameter values to obtain a final equivalent model of the new energy station.

Description

Method and system for determining new energy station equivalent model
Technical Field
The invention relates to the technical field of power systems, in particular to a method and a system for determining an equivalent model of a new energy station.
Background
In recent years, new energy sources such as wind power and photovoltaic are rapidly increased, a target vision of 'carbon peak reaching and carbon neutralization' puts higher requirements on the safety and the operation stability of a power system, and the accuracy of simulation is more highly depended on in planning and operation stages. Different from a traditional power system taking a synchronous machine as a main factor, the new energy station taking wind power and photovoltaic as main factors has the characteristics of dispersity, weak support, weak disturbance rejection, low inertia and the like, and challenges are brought to power system simulation. On the simulation scale, in order to consider the mass small power supply with low voltage level, the number of dynamic elements required to be considered in stability analysis can reach hundreds of thousands of node levels, which greatly exceeds the simulation capability of the current industrialized software, the number of simulated power supply nodes is 1-1.5 thousands according to the field station installed with more than 10MW as a unit, and large-scale electromechanical and electromagnetic simulation can be possible. In terms of simulation precision and speed, a large number of microsecond-level direct current and new energy power electronic control processes are introduced for the access of new energy, and if the new energy is simulated one by one, the problems of non-convergence of calculation, low calculation efficiency and the like are caused. The new energy station equivalent model is properly simplified and can accurately reflect the characteristics of the actual new energy station, and not only can the problem of simulation scale be solved, but also certain model accuracy can be achieved.
At present, a single-machine multiplication model is mostly adopted in the new energy station equivalent model, although the single-machine multiplication model is simplified enough, the power distribution characteristic of a new energy unit in the new energy station is ignored, for a large new energy station, especially for a wind power plant, the power distribution characteristic is large in capacity and high in output power density, the influence of a current collecting circuit in the new energy station on the accuracy of the new energy station equivalent model is not ignored, and the single-machine multiplication is in short of consideration of the influence factors.
Therefore, how to establish the new energy station equivalent model considering both the calculation efficiency and the simulation precision is a key problem which needs to be solved urgently in the aspect of new energy station equivalent modeling at present.
Disclosure of Invention
The invention provides a method and a system for determining an equivalent model of a new energy station, which aim to solve the problem of accurately determining the equivalent model of the new energy station.
In order to solve the above problem, according to an aspect of the present invention, there is provided a method of determining an equivalence model of a new energy site, the method including:
acquiring a first new energy station equivalent model;
constructing an equivalent model of the target new energy station based on the first new energy station equivalent model, and determining a second new energy station equivalent model;
when the number of first equivalence sets considering the power distribution characteristics in the second new energy station equivalence model is a first preset threshold, determining a power distribution value of each first equivalence set considering the power distribution characteristics according to a preset power distribution strategy;
when the number of second equivalent units considering the voltage distribution characteristics in the second new energy station equivalent model is a first preset threshold value, performing near-far grouping on the second equivalent units considering the voltage distribution characteristics, and determining the impedance of each second equivalent unit;
and determining operation parameter values of an equivalent unit and an equivalent transformer in the equivalent model of the second new energy station according to the operation data of the target new energy station, and performing parameter configuration on the equivalent model of the second new energy station based on the power distribution value, the impedance and the operation parameter values to obtain a final equivalent model of the new energy station.
Preferably, the first new energy site equivalence model comprises: the system comprises a new energy unit module, auxiliary equipment inside a new energy station and a station coordination control module; the station coordination control module interacts with the new energy unit module and the auxiliary equipment;
wherein, the station coordination control module comprises: the field station level control submodule and the coordination control submodule; the station level control submodule and the coordination control submodule are interacted, and can receive an active output total reference instruction value and a reactive output total reference instruction value of the new energy station; the station level control sub-module can output a new energy station level active control instruction for controlling active output of the new energy equivalent unit and a new energy station level reactive control instruction for controlling reactive output of the new energy equivalent unit to the new energy unit module; the coordination control submodule can output an auxiliary device active control instruction and an auxiliary device reactive control instruction to the auxiliary device.
Preferably, the constructing the equivalence model of the target new energy site based on the first new energy site equivalence model, and determining the second new energy site equivalence model, includes:
judging whether the target new energy station needs station level control and auxiliary equipment or not, and obtaining a judgment result;
correcting the first new energy station equivalent model according to the judgment result to obtain a corrected first new energy station equivalent model;
determining the number of first equivalent units considering the power distribution characteristics and the number of second equivalent units considering the voltage distribution according to the power distribution characteristics and the voltage distribution characteristics of the target new energy station;
and determining the second new energy field station equivalent model based on the corrected first new energy field station equivalent model according to the first equivalent unit quantity and the second equivalent unit quantity.
Preferably, the determining, according to the power distribution characteristics and the voltage distribution characteristics of the target new energy field station, a first equivalent unit number considering the power distribution characteristics and a second equivalent unit number considering the voltage distribution includes:
if the power distribution variance of the target new energy station is larger than or equal to a preset power distribution threshold, determining the number of first equivalent units considering the power distribution characteristics as a first preset number threshold; otherwise, determining the number of the first equivalent units considering the power distribution characteristics as a second preset number threshold;
if the maximum value of the voltage deviations of the first and last sections in all the feeders of the target new energy station is determined to be greater than or equal to a preset voltage distribution threshold, determining the number of second equivalent units considering the voltage distribution characteristics to be a first preset number threshold; and otherwise, determining that the number of the second equivalent units considering the voltage distribution characteristics is a second preset number threshold.
Preferably, when the number of first equivalent units considering the power distribution characteristics in the second new energy site equivalent model is a first preset threshold, determining a power distribution value of each first equivalent unit considering the power distribution characteristics according to a preset power distribution strategy includes:
when the number of the first equivalent units considering the power distribution characteristics is determined to be a first preset number threshold, based on a distribution strategy considering power, according to 1:3, distributing the input power of the first equivalence set; or
When the first equivalent unit number considering the power distribution characteristics is determined to be a first preset number threshold, based on an allocation strategy considering the transient stability limit, the allocation of the input power of the first equivalent unit is carried out according to the following formula, and the allocation method comprises the following steps:
Figure 909705DEST_PATH_IMAGE001
wherein, P1And P2The input powers of the two first equivalent units are respectively; peRated active power, n, of a single new energy source unit in the target new energy source station1The number of units which output 20 percent of rated power in the output of the units in the target new energy field station, n2The number of the units with 100% output in the target new energy station is obtained.
Preferably, when the number of second equivalent units considering the voltage distribution characteristics in the second new energy station equivalent model is a first preset threshold, performing near-far clustering on the second equivalent units considering the power distribution characteristics includes:
when the number of second equivalent machine sets considering the voltage distribution characteristics in the second new energy field station equivalent model is a first preset threshold value, dividing the equivalent machine sets into two groups which are close to each other and far away according to the distance from the new energy machine sets to a grid-connected point, converting a current collecting line inside the new energy field station into a single machine series impedance form, and then splitting the current collecting line into two machine equivalent impedance forms.
Preferably, the determining the impedance of each second equivalent unit comprises:
Figure 168648DEST_PATH_IMAGE002
wherein Z iseq1ʹ and Zeq2ʹ are the impedance of the second equivalent unit as the near end unit and the impedance of the second equivalent unit as the far end unit, respectively; zeqImpedance is consistently converted from power loss; zeq1And Zeq2The impedance from a second equivalent unit serving as a far-end unit to a second equivalent unit serving as a near-end unit and the impedance from the second equivalent unit serving as the near-end unit to a grid-connected point of the chain branch are respectively; peqFor consistent conversion of output equivalent unit input power, P, in terms of power losseq1And Peq2The input power of a second equivalent unit as a near-end unit and the input power of a second equivalent unit as a far-end unit are respectively set; u shapePCCThe grid-connected point voltage is the grid-connected point voltage of the new energy station.
Preferably, the determining, according to the operation data of the target new energy station, the operation parameter values of the equivalent unit and the equivalent transformer in the equivalent model of the second new energy station includes:
Figure 955601DEST_PATH_IMAGE003
Figure 223771DEST_PATH_IMAGE004
wherein S iseq、Peq、Qeq、Heq、DeqAnd KeqRespectively outputting apparent power, active power, reactive power, inertia constant, damping coefficient and rigidity coefficient of the equivalent unit; n represents the number of units in the equivalent cluster; si、Pi、Qi、Hi、DiAnd KiThe system comprises an i-th equivalent unit, a first control unit, a second control unit, a third control unit and a fourth control unit, wherein the first control unit is used for controlling the first control unit to control the second control unit to control the third control unit to control the fourth control unit; r isTi、xTi、GTiAnd BTiRespectively the winding resistance, the winding reactance, the excitation conductance and the excitation reactance of a box type transformer of the ith equivalent unit,
Figure 278315DEST_PATH_IMAGE005
、
Figure 239317DEST_PATH_IMAGE006
、GTeqand BTeqThe equivalent transformer of the equivalent unit comprises a winding resistance, a winding reactance, an excitation conductance and an excitation reactance.
According to another aspect of the present invention, there is provided a system for determining an equivalence model of a new energy site, the system comprising:
the model acquisition unit is used for acquiring a first new energy station equivalent model;
the second new energy station equivalence model determination unit is used for constructing an equivalence model of the target new energy station based on the first new energy station equivalence model and determining a second new energy station equivalence model;
the power distribution unit is used for determining a power distribution value of each first equivalence set considering the power distribution characteristics according to a preset power distribution strategy when the number of the first equivalence sets considering the power distribution characteristics in the second new energy station equivalence model is a first preset threshold;
the impedance determining unit is used for performing near-far grouping on the second equivalent units considering the voltage distribution characteristics when the number of the second equivalent units considering the voltage distribution characteristics in the second new energy station equivalent model is a first preset threshold value, and determining the impedance of each second equivalent unit;
and the final model determining unit is used for determining the operation parameter values of the equivalent set and the equivalent transformer in the equivalent model of the second new energy station according to the operation data of the target new energy station, and performing parameter configuration on the equivalent model of the second new energy station based on the power distribution value, the impedance and the operation parameter values to obtain a final equivalent model of the new energy station.
The invention provides a method and a system for determining an equivalent model of a new energy station, which comprise the following steps: acquiring a first new energy station equivalent model; constructing an equivalent model of the target new energy station based on the first new energy station equivalent model, and determining a second new energy station equivalent model; determining a power distribution value of each first equivalence set considering the power distribution characteristics according to a preset power distribution strategy; performing distance grouping of second equivalent units considering the voltage distribution characteristics, and determining the impedance of each second equivalent unit; and determining operation parameter values of an equivalent unit and an equivalent transformer in the equivalent model of the second new energy station according to the operation data of the target new energy station, and performing parameter configuration on the equivalent model of the second new energy station based on the power distribution value, the impedance and the operation parameter values to obtain a final equivalent model of the new energy station. According to the method, a generalized new energy station equivalent model structure is constructed, a future development mode is provided, the method is suitable for the new energy station equivalent modeling category, and the power grid simulation efficiency of the model is guaranteed and the power grid simulation precision of the new energy station equivalent model after the new energy station equivalent model is connected is improved by considering the power distribution and voltage distribution conditions inside the new energy station.
Drawings
A more complete understanding of exemplary embodiments of the present invention may be had by reference to the following drawings in which:
FIG. 1 is a flow diagram of a method 100 of determining an equivalence model of a new energy farm according to an embodiment of the invention;
FIG. 2 is a detailed topology diagram of an exemplary new energy farm according to an embodiment of the present invention;
FIG. 3 is a schematic diagram of a first new energy site equivalence model of unified architecture according to an embodiment of the invention;
FIG. 4 is a diagram of a multi-machine equivalence comparison during fault recovery according to an embodiment of the invention;
FIG. 5 is a diagram of an equivalence model of a second new energy site according to an embodiment of the invention;
FIG. 6 is a flow chart of determining a second new energy site equivalence model according to an embodiment of the invention;
FIG. 7 is a schematic diagram of the voltage profile of a new energy bank during a fault according to an embodiment of the present invention;
FIG. 8 is a schematic diagram of a conversion of the near and far fleet impedance according to an embodiment of the present invention;
FIG. 9 is a comparison graph of 35kV bus voltage when the characteristic of the wind power plant outside the station fails according to the embodiment of the invention;
FIG. 10 is a comparison graph of 35kV bus voltage when the characteristic of the wind power plant outside the station fails according to the embodiment of the invention;
FIG. 11 is a comparative graph of reactive power output for an external characteristic fault of a wind farm, according to an embodiment of the present invention;
fig. 12 is a schematic structural diagram of a system 1000 for determining an equivalence model of a new energy station according to an embodiment of the invention.
Detailed Description
The exemplary embodiments of the present invention will now be described with reference to the accompanying drawings, however, the present invention may be embodied in many different forms and is not limited to the embodiments described herein, which are provided for complete and complete disclosure of the present invention and to fully convey the scope of the present invention to those skilled in the art. The terminology used in the exemplary embodiments illustrated in the accompanying drawings is not intended to be limiting of the invention. In the drawings, the same units/elements are denoted by the same reference numerals.
Unless otherwise defined, terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Further, it will be understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense.
Fig. 1 is a flow chart of a method 100 of determining an equivalence model of a new energy farm according to an embodiment of the invention. As shown in fig. 1, the method for determining the new energy station equivalent model according to the embodiment of the present invention constructs a generalized new energy station equivalent model structure, has a future development mode, is suitable for a new energy station equivalent modeling category, and improves the power grid simulation accuracy after the new energy station equivalent model is connected to the power grid while ensuring the power grid simulation efficiency by considering the power distribution and voltage distribution conditions inside the new energy station. As shown in fig. 1, a method 100 for determining an equivalent model of a new energy station according to an embodiment of the present invention starts with step 101, and obtains a first equivalent model of a new energy station in step 101.
Preferably, the first new energy site equivalence model comprises: the system comprises a new energy unit module, auxiliary equipment inside a new energy station and a station coordination control module; the station coordination control module interacts with the new energy unit module and the auxiliary equipment;
wherein, the station coordination control module comprises: the field station level control submodule and the coordination control submodule; the station level control submodule and the coordination control submodule are interacted, and can receive an active output total reference instruction value and a reactive output total reference instruction value of the new energy station; the station level control sub-module can output a new energy station level active control instruction for controlling active output of the new energy equivalent unit and a new energy station level reactive control instruction for controlling reactive output of the new energy equivalent unit to the new energy unit module; the coordination control submodule can output an auxiliary device active control instruction and an auxiliary device reactive control instruction to the auxiliary device.
The method for determining the equivalent model of the new energy station comprises the following steps: the method comprises two parts of determination of the new energy station equivalent model and parameter determination.
As shown in FIG. 2, the detailed topology of a typical new energy station is that the new energy station internally includes m feeders, each feeder has n new energy units, where GijA new energy source unit, T, of the jth row of the ith feeder line in the detailed topology of the new energy stationijA box-type transformer of the jth new energy unit of the ith feeder line in the new energy station, ZijCollecting line impedance, T, between the jth new energy source unit and the j +1 new energy source unit on the ith feeder line in the new energy stationMIs a main transformer of a new energy station, TSVGThe step-up transformer is an SVG in the new energy station.
The first new energy station equivalent model with a unified structure provided by the embodiment of the invention is shown in fig. 3, and the new energy station equivalent model with the unified structure has a complete generalized structure. In consideration of station level unit characteristics of new energy station equivalent modeling, the proposed equivalent model structure comprises equivalent new energy unit modules, auxiliary equipment inside the new energy station, such as STATCOM, SVC and the like, and station level coordination control modules of the new energy station. Wherein, the station coordination control module comprises: the field station level control submodule and the coordination control submodule; the station level coordination control submodule of the new energy comprises new energy station level active control and new energy station level reactive control, and the coordination control submodule is used for controlling active and reactive output of auxiliary equipment inside the new energy station. PrefOutputting a total reference instruction value Q for the active power of the new energy stationrefOutputting a total reference instruction value P for the reactive power of the new energy station levelrefmodControlling the active output, Q, of the new energy equivalent unit for the new energy station level active control instructionrefmodControlling reactive power output, P, of the new energy equivalent unit for a new energy station level reactive power control instructionrefauxActive control instruction, Q, for internal auxiliary equipment of new energy stationrefauxFor the internal assistance of new energy stationsAnd controlling reactive instructions by the equipment.
The structure of the first new energy station equivalent model with the unified structure has the concept of a future development mode. In consideration of the development of the control technology of the new energy station, the internal unit of the new energy station is changed into a coordination control mode from a plug and play model. The station level control has requirements on transient state and steady state, and is not related to the voltage regulation and frequency modulation functions of the steady state. Therefore, in order to be suitable for a future power grid development mode and a new energy station with a voltage and frequency regulation function in a mirror image actual system, the equivalent model structure is provided with a plug and play control mode in a transient state period of a current new energy unit, and is also provided with a coupling simultaneous control mode in a fault period of the future new energy station.
In step 102, based on the first new energy station equivalence model, the equivalence model of the target new energy station is constructed, and a second new energy station equivalence model is determined.
Preferably, the constructing the equivalence model of the target new energy site based on the first new energy site equivalence model, and determining the second new energy site equivalence model, includes:
judging whether the target new energy station needs station level control and auxiliary equipment or not, and obtaining a judgment result;
correcting the first new energy station equivalent model according to the judgment result to obtain a corrected first new energy station equivalent model;
determining the number of first equivalent units considering the power distribution characteristics and the number of second equivalent units considering the voltage distribution according to the power distribution characteristics and the voltage distribution characteristics of the target new energy station;
and determining the second new energy field station equivalent model based on the corrected first new energy field station equivalent model according to the first equivalent unit quantity and the second equivalent unit quantity.
Preferably, the determining, according to the power distribution characteristics and the voltage distribution characteristics of the target new energy field station, a first equivalent unit number considering the power distribution characteristics and a second equivalent unit number considering the voltage distribution includes:
if the power distribution variance of the target new energy station is larger than or equal to a preset power distribution threshold, determining the number of first equivalent units considering the power distribution characteristics as a first preset number threshold; otherwise, determining the number of the first equivalent units considering the power distribution characteristics as a second preset number threshold;
if the maximum value of the voltage deviations of the first and last sections in all the feeders of the target new energy station is determined to be greater than or equal to a preset voltage distribution threshold, determining the number of second equivalent units considering the voltage distribution characteristics to be a first preset number threshold; and otherwise, determining that the number of the second equivalent units considering the voltage distribution characteristics is a second preset number threshold.
For a complete new energy station equivalence model, the equivalence-containing new energy unit, auxiliary equipment inside the new energy station, such as STATCOM, SVC, and the like, and station-level coordination control of the new energy station are required. And determining the number of equivalent units considering the power distribution characteristics in the new energy station according to the characteristics of the power distribution in the new energy station. For power distribution, active errors during fault recovery of the new energy station are mainly simulated, random distribution of power flows in a detailed model is assumed, and a two-machine equivalent model and a four-machine equivalent model considering the power distribution are respectively provided. As shown in fig. 4, compared with a single-machine equivalent model, errors of the two-machine equivalent model and the four-machine equivalent model are both reduced significantly, and considering the calculation efficiency and the error index and the actual new energy station scale, the power considering the two-machine equivalent model can meet most conditions. Therefore, in the embodiment of the present invention, the first preset number threshold is set to 2, and the first preset number threshold is set to 1.
In the implementation mode of the invention, on the basis of a first new energy station equivalent model with a unified structure, a second new energy station equivalent model is constructed based on the grouping principle of voltage distribution and power distribution according to the information of capacity, internal impedance, geographical position distribution and the like of new energy stations in actual new energy station modeling, and the structure of the equivalent model is shown in fig. 5. The equivalent model comprises three parts of an equivalent new energy unit, reactive compensation equipment and station level coordination control, the number of the equivalent units is N, and clustering equivalence can be carried out according to the actual station condition. WN represents an Nth unit of the new energy station equivalent, TN is a box type transformer of the Nth equivalent unit, ZN is equivalent impedance of a current collection circuit of the Nth equivalent unit, TM is a grid-connected main transformer of the new energy station, SVG is reactive compensation equipment of the new energy station, TSVG is a transformer of the reactive compensation equipment, and Sr is a bypass switch of the reactive compensation device.
With reference to fig. 6, the process of constructing the second new energy site equivalence model includes:
step 1, for a target new energy station, whether a station level controller needs to be considered or not and whether an equivalent new energy station is provided with auxiliary equipment or not are determined according to the category of equivalent modeling, so that a corrected new energy station equivalent model is determined.
Step 2, defining the standard deviation s of power distribution according to the power distribution characteristics of the target new energy station2Setting a power distribution threshold N1 according to the accuracy requirement of equivalent modeling, and when the power distribution of the new energy station is obvious (namely s is met)2N1), determining the first equivalent unit number (i.e. the number of equivalent machines of power distribution) considering the power distribution characteristics as a first preset number threshold 2, and determining the first equivalent unit number as a second preset number threshold 1 when the power distribution is not obvious, i.e. the power distribution does not need to be considered.
Step 3, defining a first-stage voltage deviation delta U in any feeder line in the new energy station according to the voltage distribution characteristics of the target new energy station, giving a voltage distribution threshold value N2 according to the accuracy requirement of equivalent modeling, and determining the number of second equivalent machine sets (namely the number of voltage distribution equivalent machines) considering the voltage distribution characteristics as a first preset number threshold value 2 when the voltage distribution of the new energy station is obvious (namely the maximum value delta Umax of the voltage deviation is more than or equal to N2); and when the voltage distribution is not obvious, namely the low-voltage distribution does not need to be considered, determining that the number of the second equivalent machine sets is a second preset number threshold value 1.
And 4, determining the number of the equivalent units in the new energy field station according to the number of the first equivalent units and the number of the second equivalent units, so as to determine an equivalent model of the second new energy field station.
In an embodiment of the invention, the variance s of the power distribution is defined2. As shown in fig. 2, assume that the output of the jth row of new energy source unit of the ith feeder line in the new energy station is Pij. The average output of the new energy unit in the whole new energy station is as follows:
Figure 12101DEST_PATH_IMAGE007
，
then the variance s of the power distribution can be obtained2Comprises the following steps:
Figure 552804DEST_PATH_IMAGE008
，
the power distribution threshold N1 is given according to the accuracy requirements of the actual equivalent modeling. When power distribution variance s2And when the power is more than or equal to N1, considering the influence of power distribution, wherein the number of the power clustering equivalent units is 2. When power distribution variance s2<N1, the number of power-grouping equals 1, regardless of the influence of the power distribution.
In the embodiment of the invention, the voltage deviation delta U of the first section and the last section in any feeder line inside the new energy station is defined. For any feeder line in the new energy station, the following can be obtained:
Figure 727433DEST_PATH_IMAGE009
，
in the formula, Pij、QijThe distribution is active power and reactive power U which are sent by the jth new energy source unit on the ith feeder line in the new energy stationPCCFor new energy station grid-connected point voltage, Rij、XijThe resistance and reactance of a current collecting circuit between the jth new energy source unit and the j +1 new energy source unit on the ith feeder line in the new energy station are distributed.
The voltage distribution threshold N2 is given according to the accuracy requirements of the actual equivalent modeling. When the voltage deviation delta Umax is larger than or equal to N2, the influence of voltage distribution is considered, and the number of voltage grouping equivalent units is 2. When the voltage deviation Δ Umax < N2, the number of voltage grouping equivalents is 1 at this time, regardless of the influence of the voltage distribution.
The number Z of the equivalent units in the new energy station is as follows: z = x × y;
the number of the equivalent sets considering the power distribution is determined to be x, the number of the equivalent sets considering the voltage distribution is determined to be y, and Z belongs to {1,2,4 }.
In step 103, when the number of the first equivalent units considering the power distribution characteristics in the second new energy station equivalent model is a first preset threshold, determining a power distribution value of each first equivalent unit considering the power distribution characteristics according to a preset power distribution strategy.
Preferably, when the number of first equivalent units considering the power distribution characteristics in the second new energy site equivalent model is a first preset threshold, determining a power distribution value of each first equivalent unit considering the power distribution characteristics according to a preset power distribution strategy includes:
when the number of the first equivalent units considering the power distribution characteristics is determined to be a first preset number threshold, based on a distribution strategy considering power, according to 1:3, distributing the input power of the first equivalence set; or
When the first equivalent unit number considering the power distribution characteristics is determined to be a first preset number threshold, based on an allocation strategy considering the transient stability limit, the allocation of the input power of the first equivalent unit is carried out according to the following formula, and the allocation method comprises the following steps:
Figure 593758DEST_PATH_IMAGE010
wherein, P1And P2The input powers of the two first equivalent units are respectively; peRated active power, n, of a single new energy source unit in the target new energy source station1To the order ofThe number of units for marking 20 percent of rated power output in the units in the new energy field station, n2The number of the units with 100% output in the target new energy station is obtained.
In the embodiment of the invention, after the second new energy station equivalent model is determined, if the first equivalent unit number considering the power distribution characteristics is determined to be the first preset number threshold 2, power distribution is required. Wherein the power allocation may be based on an allocation strategy taking into account power or an allocation strategy taking into account transient limits.
(1) A power allocation strategy that takes power into account. The power distribution characteristics of the new energy bank mainly affect the active recovery rate during fault recovery. According to the multi-machine equivalence comparison graph in the fault recovery period shown in fig. 4, when the power distribution adopts two-machine equivalence, the single-machine multiplication model is directly restored to the state before the fault, the time for the small-power unit in the two-machine equivalence to restore to the state before the fault is half of the time for the single-machine multiplication model to restore to the state before the fault, and then only the high-power unit provides the restoration rate, so that the following relational expression can be obtained:
Figure 352373DEST_PATH_IMAGE011
in the formula, P1、P2Power, P, input to the machine of low and high power respectivelytotalAnd k is the fault recovery rate of the equivalent unit during the fault recovery period.
The following can be obtained:
Figure 962346DEST_PATH_IMAGE012
，
namely, when the influence of power distribution needs to be considered inside the new energy station, the small power and the large power can be distributed according to the principle of 1: 3.
(2) A power allocation strategy that considers transient limits. The starting mode of the new energy station and the operating point of a single unit can have certain influence on the transient stability of the system, but analysis shows that the condition that the influence on the transient stability level of the system is worst and the power distribution characteristic of the new energy station can be embodied is as follows: the unit is fully opened, the output of the unit is 20% rated power (minimum power) and 100% rated power (maximum power) distribution, namely, the following conditions are met:
Figure 991482DEST_PATH_IMAGE013
in the formula, PeRated active power, n, for a new single energy unit1The number of units with the unit output of 20 percent of rated power, n2Is the number of units with 100% output.
The output forces of the two new energy source units considering the transient stability limit are respectively as follows:
Figure 294288DEST_PATH_IMAGE014
，
Figure 776084DEST_PATH_IMAGE015
。
if the power distribution considers transient stability limit conditions, the equivalent machine internal power is distributed according to the relation. And if not, determining the power relation of the equivalent unit according to whether the power distribution condition needs to be considered or not.
In step 104, when the number of second equivalent units considering the voltage distribution characteristics in the second new energy field station equivalent model is a first preset threshold, performing near-far grouping on the second equivalent units considering the voltage distribution characteristics, and determining the impedance of each second equivalent unit.
Preferably, when the number of second equivalent units considering the voltage distribution characteristics in the second new energy station equivalent model is a first preset threshold, performing near-far clustering on the second equivalent units considering the power distribution characteristics includes:
when the number of second equivalent machine sets considering the voltage distribution characteristics in the second new energy field station equivalent model is a first preset threshold value, dividing the equivalent machine sets into two groups which are close to each other and far away according to the distance from the new energy machine sets to a grid-connected point, converting a current collecting line inside the new energy field station into a single machine series impedance form, and then splitting the current collecting line into two machine equivalent impedance forms.
Preferably, the determining the impedance of each second equivalent unit comprises:
Figure 189748DEST_PATH_IMAGE016
wherein Z iseq1ʹ and Zeq2ʹ are the impedance of the second equivalent unit as the near end unit and the impedance of the second equivalent unit as the far end unit, respectively; zeqImpedance is consistently converted from power loss; zeq1And Zeq2The impedance from a second equivalent unit serving as a far-end unit to a second equivalent unit serving as a near-end unit and the impedance from the second equivalent unit serving as the near-end unit to a grid-connected point of the chain branch are respectively; peqFor consistent conversion of output equivalent unit input power, P, in terms of power losseq1And Peq2The input power of a second equivalent unit as a near-end unit and the input power of a second equivalent unit as a far-end unit are respectively set; u shapePCCThe grid-connected point voltage is the grid-connected point voltage of the new energy station.
And considering a voltage grouping principle, the internal voltage distribution of the new energy station mainly influences reactive errors before and after equivalence. As shown in fig. 7, an analysis is performed by taking a feeder line inside the new energy station as an example, and assuming that the impedance of a current collecting line between every two new energy units in the new energy station is 0.0005p.u., the sequence of the units inside the new energy station is gradually increased from a grid-connected point to a far point. Therefore, during the fault period, the reactive power output by the new energy source unit supports the power grid, so that the voltage distribution characteristic inside the new energy source station is obvious, and the reactive power output among the units inside the new energy source station has larger difference. Namely, the internal voltage distribution characteristics of the new energy station need to be considered according to the actual new energy station scale and the internal current collecting line impedance.
And determining the number of equivalent units considering the voltage distribution characteristics in the new energy station according to the characteristics of the voltage distribution in the new energy station. When the new energy station needs to consider near-far grouping, the new energy station is firstly divided into near-far two groups according to the distance between the new energy unit and a grid-connected point. Because the output power flow of the new energy machine group has randomness, in the process of dividing the near-far machine group, in order to simplify the processing, the near-far machine group assumes that the output power is consistent in the derivation process, namely, the near-far machine group can be defined as the impedance from the new energy machine group to the grid-connected point. As shown in fig. 8, according to the principle of consistent power loss, the internal current collecting line of the new energy station is converted into a single-machine series impedance form, and then the current collecting line is split into two-machine equivalent impedance forms, so that the near-far meaning is clear, and the complexity of directly aggregating the impedances of the near-far clusters and the judgment of the critical near-far clusters are avoided. The following relationship is obtained:
Figure 73391DEST_PATH_IMAGE017
wherein Z iseq1ʹ and Zeq2ʹ are the impedance of the second equivalent unit as the near end unit and the impedance of the second equivalent unit as the far end unit, respectively; zeqImpedance is consistently converted from power loss; zeq1And Zeq2The impedance from a second equivalent unit serving as a far-end unit to a second equivalent unit serving as a near-end unit and the impedance from the second equivalent unit serving as the near-end unit to a grid-connected point of the chain branch are respectively; peqFor consistent conversion of output equivalent unit input power, P, in terms of power losseq1And Peq2Input power, P, of a second equivalent unit as a near-end unit and a second equivalent unit as a far-end unit, respectivelyeq1=Peq2=0.5Peq；UPCCThe grid-connected point voltage is the grid-connected point voltage of the new energy station.
In step 105, according to the operation data of the target new energy station, determining operation parameter values of an equivalent unit and an equivalent transformer in the equivalent model of the second new energy station, and performing parameter configuration on the equivalent model of the second new energy station based on the power distribution value, the impedance and the operation parameter values to obtain a final equivalent model of the new energy station.
Preferably, the determining, according to the operation data of the target new energy station, the operation parameter values of the equivalent unit and the equivalent transformer in the equivalent model of the second new energy station includes:
Figure 547097DEST_PATH_IMAGE018
Figure 17655DEST_PATH_IMAGE004
wherein S iseq、Peq、Qeq、Heq、DeqAnd KeqRespectively outputting apparent power, active power, reactive power, inertia constant, damping coefficient and rigidity coefficient of the equivalent unit; n represents the number of units in the equivalent cluster; si、Pi、Qi、Hi、DiAnd KiThe system comprises an i-th equivalent unit, a first control unit, a second control unit, a third control unit and a fourth control unit, wherein the first control unit is used for controlling the first control unit to control the second control unit to control the third control unit to control the fourth control unit; r isTi、xTi、GTiAnd BTiRespectively the winding resistance, the winding reactance, the excitation conductance and the excitation reactance of a box type transformer of the ith equivalent unit,
Figure 969431DEST_PATH_IMAGE005
、
Figure 238738DEST_PATH_IMAGE006
、GTeqand BTeqThe equivalent transformer of the equivalent unit comprises a winding resistance, a winding reactance, an excitation conductance and an excitation reactance.
In the embodiment of the invention, after the model is determined, the internal parameters of the equivalent unit and the parameters of the equivalent voltage device need to be determined, and the equivalent transformer can be an equivalent box type transformer.
For the new energy unit, according to the fitting of the actual measurement curve, the parameter conversion relation of the polymerization model can be obtained:
Figure 883346DEST_PATH_IMAGE019
wherein S iseq、Peq、Qeq、Heq、DeqAnd KeqRespectively outputting apparent power, active power, reactive power, inertia constant, damping coefficient and rigidity coefficient of the equivalent unit; n represents the number of units in the equivalent cluster; si、Pi、Qi、Hi、DiAnd KiThe system comprises an i-th equivalent unit, an input unit, a control unit and a control unit.
For parameters of an equivalent box transformer, the following formula can be used to determine:
Figure 339735DEST_PATH_IMAGE020
wherein r isTi、xTi、GTiAnd BTiRespectively the winding resistance, the winding reactance, the excitation conductance and the excitation reactance of a box type transformer of the ith equivalent unit,
Figure 95201DEST_PATH_IMAGE005
、
Figure 953436DEST_PATH_IMAGE006
、GTeqand BTeqThe equivalent transformer of the equivalent unit comprises a winding resistance, a winding reactance, an excitation conductance and an excitation reactance.
Taking a certain actual wind power plant as an example, the wind power plant comprises 66 2MW doubly-fed fans, the influence of impedance and power distribution is comprehensively considered, the units in the plant are equivalent to 4 machines, the equivalent impedance value of 2 near-far machine groups is obtained by considering impedance distribution characteristics, the total output is 60% of the capacity of the wind power plant by considering power distribution, wherein the full output of the 2 equivalent machines is 35% of the rated capacity. And 4 machine equivalence calculation is carried out on the box transformer substation, and the reactance values of the variable resistors of the fan boxes are the same. Comparing the dynamic characteristics of the wind power station under three equivalent models when the fault (voltage drop to 0.3 p.u.) of the external alternating current line N-1 of the wind power plant is detected, the method comprises the following steps: comparing graphs of the output curves of the 35kV bus voltage, the active power and the reactive power of the outgoing line respectively shown in fig. 9, fig. 10 and fig. 11, the equivalence model provided by the embodiment of the invention can obviously improve the equivalence precision.
The new energy station equivalence model provided by the embodiment of the invention is generally applicable to the new energy station equivalence modeling category, has the concept of a future development mode, and provides a parameter conversion method of the new energy station equivalence model, so that the output characteristic and the disturbance response characteristic of an actual new energy station can be simulated more accurately while the power grid simulation efficiency is improved.
Fig. 12 is a schematic structural diagram of a system 1200 for determining an equivalence model of a new energy farm according to an embodiment of the invention. As shown in fig. 12, a system 1200 for determining an equivalence model of a new energy site according to an embodiment of the present invention includes: the system comprises a model obtaining unit 1201, a second new energy field station equivalent model determining unit 1202, a power distribution unit 1203, an impedance determining unit 1204 and a final model determining unit 1205.
Preferably, the model obtaining unit 1201 is configured to obtain an equivalent model of the first new energy site.
Preferably, the first new energy site equivalence model 1201, among others, includes: the system comprises a new energy unit module, auxiliary equipment inside a new energy station and a station coordination control module; the station coordination control module interacts with the new energy unit module and the auxiliary equipment;
wherein, the station coordination control module comprises: the field station level control submodule and the coordination control submodule; the station level control submodule and the coordination control submodule are interacted, and can receive an active output total reference instruction value and a reactive output total reference instruction value of the new energy station; the station level control sub-module can output a new energy station level active control instruction for controlling active output of the new energy equivalent unit and a new energy station level reactive control instruction for controlling reactive output of the new energy equivalent unit to the new energy unit module; the coordination control submodule can output an auxiliary device active control instruction and an auxiliary device reactive control instruction to the auxiliary device.
Preferably, the second new energy site equivalence model determining unit 1202 is configured to construct an equivalence model of the target new energy site based on the first new energy site equivalence model, and determine a second new energy site equivalence model.
Preferably, the second new energy site equivalence model determining unit 1202, based on the first new energy site equivalence model, performs construction of an equivalence model of a target new energy site, and determining the second new energy site equivalence model, including:
judging whether the target new energy station needs station level control and auxiliary equipment or not, and obtaining a judgment result;
correcting the first new energy station equivalent model according to the judgment result to obtain a corrected first new energy station equivalent model;
determining the number of first equivalent units considering the power distribution characteristics and the number of second equivalent units considering the voltage distribution according to the power distribution characteristics and the voltage distribution characteristics of the target new energy station;
and determining the second new energy field station equivalent model based on the corrected first new energy field station equivalent model according to the first equivalent unit quantity and the second equivalent unit quantity.
Preferably, the determining unit 1202 for the second new energy site equivalence model determines, according to the power distribution characteristics and the voltage distribution characteristics of the target new energy site, a first number of equivalence sets considering the power distribution characteristics and a second number of equivalence sets considering the voltage distribution, including:
if the power distribution variance of the target new energy station is larger than or equal to a preset power distribution threshold, determining the number of first equivalent units considering the power distribution characteristics as a first preset number threshold; otherwise, determining the number of the first equivalent units considering the power distribution characteristics as a second preset number threshold;
if the maximum value of the voltage deviations of the first and last sections in all the feeders of the target new energy station is determined to be greater than or equal to a preset voltage distribution threshold, determining the number of second equivalent units considering the voltage distribution characteristics to be a first preset number threshold; and otherwise, determining that the number of the second equivalent units considering the voltage distribution characteristics is a second preset number threshold.
Preferably, the power allocation unit 1203 is configured to determine, according to a preset power allocation policy, a power allocation value of each first equivalence set considering the power distribution characteristics when the number of the first equivalence sets considering the power distribution characteristics in the second new energy site equivalence model is a first preset threshold.
Preferably, when the number of the first equivalent units considering the power distribution characteristics in the second new energy field station equivalent model is a first preset threshold, the determining, according to a preset power distribution policy, a power distribution value of each first equivalent unit considering the power distribution characteristics includes:
when the number of the first equivalent units considering the power distribution characteristics is determined to be a first preset number threshold, based on a distribution strategy considering power, according to 1:3, distributing the input power of the first equivalence set; or
When the first equivalent unit number considering the power distribution characteristics is determined to be a first preset number threshold, based on an allocation strategy considering the transient stability limit, the allocation of the input power of the first equivalent unit is carried out according to the following formula, and the allocation method comprises the following steps:
Figure 503366DEST_PATH_IMAGE021
wherein, P1And P2The input powers of the two first equivalent units are respectively; peRated active power, n, of a single new energy source unit in the target new energy source station1The number of units which output 20 percent of rated power in the output of the units in the target new energy field station, n2For the target new energyThe number of units with 120% output in the source station.
Preferably, the impedance determining unit 1204 is configured to, when the number of second equivalent units considering the voltage distribution characteristics in the second new energy station equivalent model is a first preset threshold, perform near-far clustering on the second equivalent units considering the voltage distribution characteristics, and determine the impedance of each second equivalent unit.
Preferably, when the number of second equivalent units considering the voltage distribution characteristics in the second new energy field station equivalent model is a first preset threshold, the impedance determining unit 1204 performs near-far clustering on the second equivalent units considering the power distribution characteristics, including:
when the number of second equivalent machine sets considering the voltage distribution characteristics in the second new energy field station equivalent model is a first preset threshold value, dividing the equivalent machine sets into two groups which are close to each other and far away according to the distance from the new energy machine sets to a grid-connected point, converting a current collecting line inside the new energy field station into a single machine series impedance form, and then splitting the current collecting line into two machine equivalent impedance forms.
Preferably, the determining the impedance of each second equivalent unit by the impedance determining unit 1204 includes:
Figure 211166DEST_PATH_IMAGE022
wherein Z iseq1ʹ and Zeq2ʹ are the impedance of the second equivalent unit as the near end unit and the impedance of the second equivalent unit as the far end unit, respectively; zeqImpedance is consistently converted from power loss; zeq1And Zeq2The impedance from a second equivalent unit serving as a far-end unit to a second equivalent unit serving as a near-end unit and the impedance from the second equivalent unit serving as the near-end unit to a grid-connected point of the chain branch are respectively; peqFor consistent conversion of output equivalent unit input power, P, in terms of power losseq1And Peq2The input power of a second equivalent unit as a near-end unit and the input power of a second equivalent unit as a far-end unit are respectively set; u shapePCCTo become newSource field station grid-connected point voltage.
Preferably, the final model determining unit 1205 is configured to determine, according to the operation data of the target new energy station, operation parameter values of an equivalent unit and an equivalent transformer in the second new energy station equivalent model, and perform parameter configuration on the second new energy station equivalent model based on the power distribution value, the impedance, and the operation parameter values, so as to obtain a final new energy station equivalent model.
Preferably, the final model determining unit 1205 determines, according to the operation data of the target new energy station, operation parameter values of an equivalent unit and an equivalent transformer in the equivalent model of the second new energy station, including:
Figure 770323DEST_PATH_IMAGE023
Figure 483064DEST_PATH_IMAGE004
wherein S iseq、Peq、Qeq、Heq、DeqAnd KeqRespectively outputting apparent power, active power, reactive power, inertia constant, damping coefficient and rigidity coefficient of the equivalent unit; n represents the number of units in the equivalent cluster; si、Pi、Qi、Hi、DiAnd KiThe system comprises an i-th equivalent unit, a first control unit, a second control unit, a third control unit and a fourth control unit, wherein the first control unit is used for controlling the first control unit to control the second control unit to control the third control unit to control the fourth control unit; r isTi、xTi、GTiAnd BTiRespectively the winding resistance, the winding reactance, the excitation conductance and the excitation reactance of a box type transformer of the ith equivalent unit,
Figure 203895DEST_PATH_IMAGE005
、
Figure 634877DEST_PATH_IMAGE006
、GTeqand BTeqThe equivalent transformer of the equivalent unit comprises a winding resistance, a winding reactance, an excitation conductance and an excitation reactance.
The system 1200 for determining the new energy station equivalence model according to the embodiment of the present invention corresponds to the method 100 for determining the new energy station equivalence model according to another embodiment of the present invention, and details thereof are not repeated herein.
The invention has been described with reference to a few embodiments. However, other embodiments of the invention than the one disclosed above are equally possible within the scope of the invention, as would be apparent to a person skilled in the art from the appended patent claims.
Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to "a/an/the [ device, component, etc ]" are to be interpreted openly as referring to at least one instance of said device, component, etc., unless explicitly stated otherwise. The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless explicitly stated.
As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting the same, and although the present invention is described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: modifications and equivalents may be made to the embodiments of the invention without departing from the spirit and scope of the invention, which is to be covered by the claims.

Claims (16)

1. A method of determining an equivalence model for a new energy site, the method comprising:
acquiring a first new energy station equivalent model;
constructing an equivalent model of the target new energy station based on the first new energy station equivalent model, and determining a second new energy station equivalent model;
when the number of first equivalence sets considering the power distribution characteristics in the second new energy station equivalence model is a first preset threshold, determining a power distribution value of each first equivalence set considering the power distribution characteristics according to a preset power distribution strategy;
when the number of second equivalent units considering the voltage distribution characteristics in the second new energy station equivalent model is a first preset threshold value, performing near-far grouping on the second equivalent units considering the voltage distribution characteristics, and determining the impedance of each second equivalent unit;
and determining operation parameter values of an equivalent unit and an equivalent transformer in the equivalent model of the second new energy station according to the operation data of the target new energy station, and performing parameter configuration on the equivalent model of the second new energy station based on the power distribution value, the impedance and the operation parameter values to obtain a final equivalent model of the new energy station.
2. The method of claim 1, wherein the first new energy site equivalence model comprises: the system comprises a new energy unit module, auxiliary equipment inside a new energy station and a station coordination control module; the station coordination control module interacts with the new energy unit module and the auxiliary equipment;
wherein, the station coordination control module comprises: the field station level control submodule and the coordination control submodule; the station level control submodule and the coordination control submodule are interacted, and can receive an active output total reference instruction value and a reactive output total reference instruction value of the new energy station; the station level control sub-module can output a new energy station level active control instruction for controlling active output of the new energy equivalent unit and a new energy station level reactive control instruction for controlling reactive output of the new energy equivalent unit to the new energy unit module; the coordination control submodule can output an auxiliary device active control instruction and an auxiliary device reactive control instruction to the auxiliary device.
3. The method according to claim 1, wherein the constructing the equivalence model of the target new energy site based on the first new energy site equivalence model, and the determining the equivalence model of the second new energy site comprises:
judging whether the target new energy station needs station level control and auxiliary equipment or not, and obtaining a judgment result;
correcting the first new energy station equivalent model according to the judgment result to obtain a corrected first new energy station equivalent model;
determining the number of first equivalent units considering the power distribution characteristics and the number of second equivalent units considering the voltage distribution according to the power distribution characteristics and the voltage distribution characteristics of the target new energy station;
and determining the second new energy field station equivalent model based on the corrected first new energy field station equivalent model according to the first equivalent unit quantity and the second equivalent unit quantity.
4. The method according to claim 3, wherein the determining a first number of equivalent crew units considering power distribution characteristics and a second number of equivalent crew units considering voltage distribution characteristics from the power distribution characteristics and the voltage distribution characteristics of the target new energy site comprises:
if the power distribution variance of the target new energy station is larger than or equal to a preset power distribution threshold, determining the number of first equivalent units considering the power distribution characteristics as a first preset number threshold; otherwise, determining the number of the first equivalent units considering the power distribution characteristics as a second preset number threshold;
if the maximum value of the voltage deviations of the first and last sections in all the feeders of the target new energy station is determined to be greater than or equal to a preset voltage distribution threshold, determining the number of second equivalent units considering the voltage distribution characteristics to be a first preset number threshold; and otherwise, determining that the number of the second equivalent units considering the voltage distribution characteristics is a second preset number threshold.
5. The method according to claim 1, wherein when the number of first equivalent units considering the power distribution characteristics in the second new energy site equivalent model is a first preset threshold, determining the power distribution value of each first equivalent unit considering the power distribution characteristics according to a preset power distribution strategy comprises:
when the number of the first equivalent units considering the power distribution characteristics is determined to be a first preset number threshold, based on a distribution strategy considering power, according to 1:3, distributing the input power of the first equivalence set; or
When the first equivalent unit number considering the power distribution characteristics is determined to be a first preset number threshold, based on an allocation strategy considering the transient stability limit, the allocation of the input power of the first equivalent unit is carried out according to the following formula, and the allocation method comprises the following steps:
Figure 635901DEST_PATH_IMAGE001
，
Figure 160423DEST_PATH_IMAGE002
，
wherein, P1And P2The input powers of the two first equivalent units are respectively; peRated active power, n, of a single new energy source unit in the target new energy source station1The number of units which output 20 percent of rated power in the output of the units in the target new energy field station, n2The number of the units with 100% output in the target new energy station is obtained.
6. The method according to claim 1, wherein when the number of second equivalent units considering the voltage distribution characteristics in the second new energy station equivalent model is a first preset threshold, performing near-far clustering on the second equivalent units considering the power distribution characteristics comprises:
when the number of second equivalent machine sets considering the voltage distribution characteristics in the second new energy field station equivalent model is a first preset threshold value, dividing the equivalent machine sets into two groups which are close to each other and far away according to the distance from the new energy machine sets to a grid-connected point, converting a current collecting line inside the new energy field station into a single machine series impedance form, and then splitting the current collecting line into two machine equivalent impedance forms.
7. The method of claim 6, wherein said determining the impedance of each second equivalent assembly comprises:
Figure 445911DEST_PATH_IMAGE003
,
Figure 714082DEST_PATH_IMAGE004
,
Figure 768625DEST_PATH_IMAGE005
，
Figure 464049DEST_PATH_IMAGE006
，
wherein Z iseq1ʹ and Zeq2ʹ are the impedance of the second equivalent unit as the near end unit and the impedance of the second equivalent unit as the far end unit, respectively; zeqImpedance is consistently converted from power loss; zeq1And Zeq2The impedance from a second equivalent unit serving as a far-end unit to a second equivalent unit serving as a near-end unit and the impedance from the second equivalent unit serving as the near-end unit to a grid-connected point of the chain branch are respectively; peqFor consistent conversion of output equivalent unit input power, P, in terms of power losseq1And Peq2The input power of a second equivalent unit as a near-end unit and the input power of a second equivalent unit as a far-end unit are respectively set; u shapePCCThe grid-connected point voltage is the grid-connected point voltage of the new energy station.
8. The method according to claim 1, wherein the determining the operation parameter values of the equivalent units and the equivalent transformers in the equivalent model of the second new energy station according to the operation data of the target new energy station comprises:
Figure 947DEST_PATH_IMAGE007
Figure 541650DEST_PATH_IMAGE008
wherein S iseq、Peq、Qeq、Heq、DeqAnd KeqRespectively outputting apparent power, active power, reactive power, inertia constant, damping coefficient and rigidity coefficient of the equivalent unit; n represents the number of units in the equivalent cluster; si、Pi、Qi、Hi、DiAnd KiThe system comprises an i-th equivalent unit, a first control unit, a second control unit, a third control unit and a fourth control unit, wherein the first control unit is used for controlling the first control unit to control the second control unit to control the third control unit to control the fourth control unit; r isTi、xTi、GTiAnd BTiRespectively the winding resistance, the winding reactance, the excitation conductance and the excitation reactance of a box type transformer of the ith equivalent unit,
Figure 716279DEST_PATH_IMAGE009
、
Figure 582604DEST_PATH_IMAGE010
、GTeqand BTeqThe equivalent transformer of the equivalent unit comprises a winding resistance, a winding reactance, an excitation conductance and an excitation reactance.
9. A system for determining an equivalence model for a new energy site, the system comprising:
the model acquisition unit is used for acquiring a first new energy station equivalent model;
the second new energy station equivalence model determination unit is used for constructing an equivalence model of the target new energy station based on the first new energy station equivalence model and determining a second new energy station equivalence model;
the power distribution unit is used for determining a power distribution value of each first equivalence set considering the power distribution characteristics according to a preset power distribution strategy when the number of the first equivalence sets considering the power distribution characteristics in the second new energy station equivalence model is a first preset threshold;
the impedance determining unit is used for performing near-far grouping on the second equivalent units considering the voltage distribution characteristics when the number of the second equivalent units considering the voltage distribution characteristics in the second new energy station equivalent model is a first preset threshold value, and determining the impedance of each second equivalent unit;
and the final model determining unit is used for determining the operation parameter values of the equivalent set and the equivalent transformer in the equivalent model of the second new energy station according to the operation data of the target new energy station, and performing parameter configuration on the equivalent model of the second new energy station based on the power distribution value, the impedance and the operation parameter values to obtain a final equivalent model of the new energy station.
10. The system of claim 9, wherein the first new energy site equivalence model comprises: the system comprises a new energy unit module, auxiliary equipment inside a new energy station and a station coordination control module; the station coordination control module interacts with the new energy unit module and the auxiliary equipment;
wherein, the station coordination control module comprises: the field station level control submodule and the coordination control submodule; the station level control submodule and the coordination control submodule are interacted, and can receive an active output total reference instruction value and a reactive output total reference instruction value of the new energy station; the station level control sub-module can output a new energy station level active control instruction for controlling active output of the new energy equivalent unit and a new energy station level reactive control instruction for controlling reactive output of the new energy equivalent unit to the new energy unit module; the coordination control submodule can output an auxiliary device active control instruction and an auxiliary device reactive control instruction to the auxiliary device.
11. The system according to claim 9, wherein the second new energy site equivalence model determining unit, based on the first new energy site equivalence model, constructs an equivalence model of the target new energy site, and determines the second new energy site equivalence model, including:
judging whether the target new energy station needs station level control and auxiliary equipment or not, and obtaining a judgment result;
correcting the first new energy station equivalent model according to the judgment result to obtain a corrected first new energy station equivalent model;
determining the number of first equivalent units considering the power distribution characteristics and the number of second equivalent units considering the voltage distribution according to the power distribution characteristics and the voltage distribution characteristics of the target new energy station;
and determining the second new energy field station equivalent model based on the corrected first new energy field station equivalent model according to the first equivalent unit quantity and the second equivalent unit quantity.
12. The system according to claim 11, wherein the second new energy site equivalence model determining unit determines, according to the power distribution characteristics and the voltage distribution characteristics of the target new energy site, a first equivalence group number considering the power distribution characteristics and a second equivalence group number considering the voltage distribution, including:
if the power distribution variance of the target new energy station is larger than or equal to a preset power distribution threshold, determining the number of first equivalent units considering the power distribution characteristics as a first preset number threshold; otherwise, determining the number of the first equivalent units considering the power distribution characteristics as a second preset number threshold;
if the maximum value of the voltage deviations of the first and last sections in all the feeders of the target new energy station is determined to be greater than or equal to a preset voltage distribution threshold, determining the number of second equivalent units considering the voltage distribution characteristics to be a first preset number threshold; and otherwise, determining that the number of the second equivalent units considering the voltage distribution characteristics is a second preset number threshold.
13. The system according to claim 9, wherein the power distribution unit, when the number of first equivalence groups considering the power distribution characteristics in the second new energy site equivalence model is a first preset threshold, determining the power distribution value of each first equivalence group considering the power distribution characteristics according to a preset power distribution strategy, includes:
when the number of the first equivalent units considering the power distribution characteristics is determined to be a first preset number threshold, based on a distribution strategy considering power, according to 1:3, distributing the input power of the first equivalence set; or
When the first equivalent unit number considering the power distribution characteristics is determined to be a first preset number threshold, based on an allocation strategy considering the transient stability limit, the allocation of the input power of the first equivalent unit is carried out according to the following formula, and the allocation method comprises the following steps:
Figure 842684DEST_PATH_IMAGE001
，
Figure 452657DEST_PATH_IMAGE002
，
wherein, P1And P2The input powers of the two first equivalent units are respectively; peRated active power, n, of a single new energy source unit in the target new energy source station1The number of units which output 20 percent of rated power in the output of the units in the target new energy field station, n2The number of the units with 100% output in the target new energy station is obtained.
14. The system according to claim 9, wherein the impedance determination unit, when the number of second equivalent units considering the voltage distribution characteristics in the second new energy station equivalent model is a first preset threshold, performs near-far clustering on the second equivalent units considering the power distribution characteristics, and includes:
when the number of second equivalent machine sets considering the voltage distribution characteristics in the second new energy field station equivalent model is a first preset threshold value, dividing the equivalent machine sets into two groups which are close to each other and far away according to the distance from the new energy machine sets to a grid-connected point, converting a current collecting line inside the new energy field station into a single machine series impedance form, and then splitting the current collecting line into two machine equivalent impedance forms.
15. The system of claim 14, wherein the impedance determination unit determines the impedance of each second equivalent aggregate, comprising:
Figure 481793DEST_PATH_IMAGE003
,
Figure 784598DEST_PATH_IMAGE011
,
Figure 502281DEST_PATH_IMAGE005
，
Figure 915945DEST_PATH_IMAGE006
，
wherein Z iseq1ʹ and Zeq2ʹ are the impedance of the second equivalent unit as the near end unit and the impedance of the second equivalent unit as the far end unit, respectively; zeqImpedance is consistently converted from power loss; zeq1And Zeq2Impedance from a second equivalent unit as a far end unit to a second equivalent unit as a near end unit, and a second equivalent unit as a near end unit, which are respectively chain branchesThe impedance from the unit to the grid connection point is evaluated; peqFor consistent conversion of output equivalent unit input power, P, in terms of power losseq1And Peq2The input power of a second equivalent unit as a near-end unit and the input power of a second equivalent unit as a far-end unit are respectively set; u shapePCCThe grid-connected point voltage is the grid-connected point voltage of the new energy station.
16. The system according to claim 9, wherein the final model determining unit determines the operation parameter values of the equivalent set and the equivalent transformer in the equivalent model of the second new energy station according to the operation data of the target new energy station, and comprises:
Figure 799587DEST_PATH_IMAGE012
Figure 273294DEST_PATH_IMAGE008
wherein S iseq、Peq、Qeq、Heq、DeqAnd KeqRespectively outputting apparent power, active power, reactive power, inertia constant, damping coefficient and rigidity coefficient of the equivalent unit; n represents the number of units in the equivalent cluster; si、Pi、Qi、Hi、DiAnd KiThe system comprises an i-th equivalent unit, a first control unit, a second control unit, a third control unit and a fourth control unit, wherein the first control unit is used for controlling the first control unit to control the second control unit to control the third control unit to control the fourth control unit; r isTi、xTi、GTiAnd BTiRespectively the winding resistance, the winding reactance, the excitation conductance and the excitation reactance of a box type transformer of the ith equivalent unit,
Figure 242387DEST_PATH_IMAGE009
、
Figure 194162DEST_PATH_IMAGE010
、GTeqand BTeqThe equivalent transformer of the equivalent unit comprises a winding resistance, a winding reactance, an excitation conductance and an excitation reactance.
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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102682358A (en) * 2012-03-30 2012-09-19 中国电力科学研究院 Planning simulation method for estimating adaptability of wind power grid-connection scale and power grid net rack
EP2869144A1 (en) * 2013-11-05 2015-05-06 Jinan Railway Vehicles Equipment Co., Ltd. Simulation testing platform for wind power plant and testing method thereof
US10126802B1 (en) * 2017-06-06 2018-11-13 Chongqing University Method and device for determining static equivalences of distribution networks
CN113642195A (en) * 2021-10-14 2021-11-12 中国电力科学研究院有限公司 New energy field station-level modeling practical equivalence method and device

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102682358A (en) * 2012-03-30 2012-09-19 中国电力科学研究院 Planning simulation method for estimating adaptability of wind power grid-connection scale and power grid net rack
EP2869144A1 (en) * 2013-11-05 2015-05-06 Jinan Railway Vehicles Equipment Co., Ltd. Simulation testing platform for wind power plant and testing method thereof
US10126802B1 (en) * 2017-06-06 2018-11-13 Chongqing University Method and device for determining static equivalences of distribution networks
CN113642195A (en) * 2021-10-14 2021-11-12 中国电力科学研究院有限公司 New energy field station-level modeling practical equivalence method and device

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
基于频域阻抗分析的直驱风电场等值建模方法;周佩朋等;《中国电机工程学报》;20200831;全文 *

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