CN103886182A

CN103886182A - Parameter equating method for aggregation model of doubly-fed generator set wind power station

Info

Publication number: CN103886182A
Application number: CN201410064836.8A
Authority: CN
Inventors: 汪宁渤; 丁坤; 路亮; 蔡旭; 张琛; 李津; 周识远; 李征; 张金平; 夏玥
Original assignee: State Grid Corp of China SGCC; State Grid Gansu Electric Power Co Ltd; Wind Power Technology Center of Gansu Electric Power Co Ltd; Shanghai Jiao Tong University
Current assignee: State Grid Corp of China SGCC; State Grid Gansu Electric Power Co Ltd; Wind Power Technology Center of Gansu Electric Power Co Ltd; Shanghai Jiao Tong University
Priority date: 2014-02-25
Filing date: 2014-02-25
Publication date: 2014-06-25

Abstract

The invention discloses a double-fed unit wind farm aggregation model parameter equivalent method, which mainly includes: respectively performing generator model parameter equivalents, shafting parameter equivalents, transformer parameter equivalents, wind speed Equivalence: Equivalent processing is carried out on the internal collector lines of the wind farm according to the wiring method, and then the aggregation equivalent parameters of the above-mentioned links are integrated to obtain the aggregation model of the DFIG wind farm. The method for equivalent value of the wind farm aggregation model parameters of the doubly-fed unit in the present invention can overcome the defects of poor stability, low reliability and small application range in the existing wind farm aggregation modeling technology, so as to achieve good stability, high reliability and The advantages of wide application range.

Description

A Parameter Equivalence Method for Doubly-fed Unit Wind Farm Aggregation Model

技术领域technical field

本发明涉及风力发电及其并网控制的风电场等值建模技术领域，具体地，涉及一种双馈机组风电场聚合模型参数等值方法。The present invention relates to the technical field of equivalent modeling of wind farms for wind power generation and grid-connected control thereof, in particular to a parameter equivalent method for wind farm aggregation models of double-fed units.

背景技术Background technique

我国风电进入规模化发展阶段以后所产生的大型风电基地多数位于“三北地区”（西北、东北、华北），大型风电基地一般远离负荷中心，其电力需要经过长距离、高电压输送到负荷中心进行消纳。由于风资源的间歇性、随机性和波动性，导致大规模风电基地的风电出力会随之发生较大范围的波动，进一步导致输电网络充电功率的波动，给电网运行安全带来一系列问题。Most of the large-scale wind power bases generated after my country's wind power enters the stage of large-scale development are located in the "Three North Regions" (Northwest, Northeast, and North China). Large-scale wind power bases are generally far away from the load center, and their power needs to be transmitted to the load center through long distances and high voltage. To digest. Due to the intermittence, randomness and volatility of wind resources, the wind power output of large-scale wind power bases will fluctuate in a large range, which will further lead to fluctuations in the charging power of the transmission network and bring a series of problems to the safety of power grid operation.

截至2013年11月，甘肃电网并网风电装机容量已达到668万千瓦，约占甘肃电网总装机容量的21%，成为仅次于火电的第二大主力电源。随着风电并网规模的不断提高，风力发电的不确定性和不可控性给电网的安全稳定经济运行带来诸多问题。因此需要对大规模风力发电的相关问题进行深入分析研究，尤其需要研究大规模风电集中并网情况下的风电场聚合模型问题，用于含大规模风电的电力系统分析计算。As of November 2013, Gansu grid-connected wind power installed capacity has reached 6.68 million kilowatts, accounting for about 21% of the total installed capacity of Gansu grid, becoming the second largest main power source after thermal power. With the continuous increase of wind power grid-connected scale, the uncertainty and uncontrollability of wind power generation have brought many problems to the safe, stable and economical operation of the power grid. Therefore, it is necessary to carry out in-depth analysis and research on the related issues of large-scale wind power generation, especially the problem of wind farm aggregation model in the case of large-scale wind power centralized grid connection, which is used for the analysis and calculation of power systems containing large-scale wind power.

在实现本发明的过程中，发明人发现现有技术中至少存在稳定性差、可靠性低和适用范围小等缺陷。During the process of realizing the present invention, the inventors found that the prior art at least has defects such as poor stability, low reliability and narrow application range.

发明内容Contents of the invention

本发明的目的在于，针对上述问题，提出一种双馈机组风电场聚合模型参数等值方法，以实现稳定性好、可靠性高和适用范围大的优点。The purpose of the present invention is to solve the above problems and propose an equivalent method for the aggregation model parameters of the doubly-fed unit wind farm, so as to achieve the advantages of good stability, high reliability and wide application range.

为实现上述目的，本发明采用的技术方案是：一种双馈机组风电场聚合模型参数等值方法，主要包括：分别对双馈机组进行等值处理，对风电场内部集电线路进行等值处理，整合得到该双馈机组风电场的聚合模型。In order to achieve the above object, the technical solution adopted by the present invention is: a double-fed unit wind farm aggregation model parameter equivalent method, which mainly includes: performing equivalent processing on the double-fed unit respectively, and performing equivalent value on the internal collector lines of the wind farm processing and integration to obtain the aggregation model of the DFIG wind farm.

进一步地，所述对双馈机组进行等值处理的操作，至少包括：Further, the operation of performing equivalent treatment on the doubly-fed unit at least includes:

a、对双馈机组的发电机模型参数进行等值处理；a. Perform equivalent processing on the generator model parameters of the doubly-fed unit;

b、对双馈机组的轴系参数进行等值处理；b. Perform equivalent treatment on the shafting parameters of the doubly-fed unit;

c、对双馈机组的变压器参数进行等值处理；c. Perform equivalent processing on the transformer parameters of the doubly-fed unit;

d、对双馈机组的风速进行等值处理。d. Perform equivalent processing on the wind speed of the doubly-fed unit.

进一步地，所述步骤a，具体包括：Further, said step a specifically includes:

假定n台同型号的风力发电机中有m台等值成为1台机组，则等值计算公式如下：Assuming that among n wind turbines of the same model, there are m units equivalent to one unit, the equivalent calculation formula is as follows:

$\{\begin{matrix} {S S}_{eq eq} = = {Σ Σ}_{i i = = 11}^{m m} {S S}_{i i} = = mS M,, \\ {P P}_{eq eq} = = {Σ Σ}_{i i = = 11}^{m m} {P P}_{i i} = = mP mP,, {Q Q}_{eq eq} = = {Σ Σ}_{i i = = 11}^{m m} {Q Q}_{i i} = = mQ mQ \\ {X x}_{m m - - eq eq} = = \frac{{x x}_{m m}}{m m} \\ {X x}_{s the s - - eq eq} = = \frac{{x x}_{s the s}}{m m},, {X x}_{r r - - eq eq} = = \frac{{x x}_{r r}}{m m},, \\ {r r}_{s the s - - eq eq} = = \frac{{r r}_{s the s}}{m m},, {r r}_{r r - - eq eq} = = \frac{{r r}_{s the s}}{m m} \end{matrix} - - - - - - ((11));;$

在公式（1）中，S_eq表示等效发电机容量，S_i表示第i台发电机容量；m为风电机组台数；P_eq表示等效后的有功功率；P_i表示第i台机组的有功功率；P表示各机组的平均有功功率；Q_eq表示等效后的无功功率；Q_i表示第i台机组的无功功率；Q表示各机组的平均无功功率；X_m-eq为等效后的发电机励磁电抗；x_m为发电机励磁电抗；X_s-eq为等效后的发电机定子电抗；x_s为发电机定子电抗；X_r-eq为等效后的发电机转子电抗；x_r为发电机转子电抗；r_s-eq为等效后的发电机定子电阻；r_s为发电机定子电阻；r_r-eq为等效后的发电机转子电阻；r_r为发电机转子电阻。In formula (1), S _eq represents the equivalent generator capacity, S _i represents the capacity of the i-th generator; m is the number of wind turbines; P _eq represents the equivalent active power; P _i represents the power of the i-th generator Active power; P represents the average active power of each unit; Q _eq represents the equivalent reactive power; Q _i represents the reactive power of the i-th unit; Q represents the average reactive power of each unit; X _m-eq is Equivalent generator excitation reactance; x _m is generator excitation reactance; X _s-eq is equivalent generator stator reactance; x _s is generator stator reactance; X _r-eq is equivalent generator rotor reactance; x _r is generator rotor reactance; r _s-eq is equivalent generator stator resistance; r _s is generator stator resistance; r _r-eq is equivalent generator rotor resistance; r _r is Generator rotor resistance.

进一步地，在步骤b中，所述对轴系参数进行等值的公式为：Further, in step b, the formula for equivalent value of the shafting parameters is:

$\{\begin{matrix} {H h}_{g g__eq eq} = = {Σ Σ}_{i i = = 11}^{m m} {H h}_{gi gi} = = m m {H h}_{g g} \\ {H h}_{t t__eq eq} = = {Σ Σ}_{i i = = 11}^{m m} {H h}_{ti ti} = = m m {H h}_{t t} \\ {H h}_{s the s__eq eq} = = {Σ Σ}_{i i = = 11}^{m m} {H h}_{si the si} = = m m {H h}_{s the s} \end{matrix} - - - - - - ((22));;$

在公式（2）中，H_{g_eq}为等效后的发电机转子惯性时间常数；H_g为发电机转子惯性时间常数；H_{t_eq}为等效后的风力机转子惯性时间常数；H_t为风力机转子惯性时间常数；K_{s_eq}为等效后的轴系刚度系数；K_s为轴系刚度系数；m为风电机组台数。In formula (2), H _{g_eq} is the equivalent generator rotor inertia time constant; H _g is the generator rotor inertia time constant; H _{t_eq} is the equivalent wind turbine rotor inertia time constant; H _t is the wind turbine Rotor inertia time constant; K _{s_eq} is the equivalent shaft stiffness coefficient; K _s is the shaft stiffness coefficient; m is the number of wind turbines.

进一步地，在步骤c中，所述对变压器参数进行等值的公式为。Further, in step c, the formula for performing equivalent values of the transformer parameters is as follows.

$\{\begin{matrix} {S S}_{T T__eq eq} = = {mS M}_{T T} \\ {Z Z}_{T T__eq eq} = = \frac{{Z Z}_{T T}}{m m} \end{matrix} - - - - - - ((33));;$

在公式（3）中，S_{T_eq}为等效后的变压器容量；S_T为变压器容量；Z_{T_eq}为等效后的变压器阻抗；Z_T为变压器阻抗；m为风电机组台数。In formula (3), S _{T_eq} is the equivalent transformer capacity; S _T is the transformer capacity; Z _{T_eq} is the equivalent transformer impedance; Z _T is the transformer impedance; m is the number of wind turbines.

进一步地，在步骤d中，所述对风速进行等值的操作，具体包括：Further, in step d, the operation of performing an equivalent value on the wind speed specifically includes:

采用基于桨距角动作情况的分群法时，等效风速为：When using the grouping method based on the action of the pitch angle, the equivalent wind speed is:

${v v}_{eq eq} = = \frac{11}{m m} {Σ Σ}_{i i = = 11}^{m m} {v v}_{i i} - - - - - - ((44));;$

在公式（4）中，v_i为第i台机组俘获的风速；则聚合模型捕获的机械功率为：In formula (4), v _i is the wind speed captured by unit i; then the mechanical power captured by the aggregation model is:

${P P}_{m m} = = m m ((\frac{11}{22} ρ ρ {AC AC}_{p p max max} {V V}_{eq eq}^{33})) - - - - - - ((55));;$

在公式（5）中，m为机组台数，ρ为风功率密度，A为机组扫风面积，C_pmax为最大风能利用系数，v_eq为等效风速。In formula (5), m is the number of units, ρ is the wind power density, A is the swept area of the unit, C _pmax is the maximum wind energy utilization coefficient, and v _eq is the equivalent wind speed.

进一步地，在对风电场内部集电线路进行等值的操作，需要根据风电场内部集电线路的接线方式采用不同的处理方法，具体包括：Furthermore, when performing equivalent operations on the internal collector lines of the wind farm, different processing methods need to be adopted according to the wiring mode of the internal collector lines of the wind farm, specifically including:

1）当风电场内部集电线路的接线方式为干线式接线方式时，等值阻抗为：1) When the wiring mode of the internal collector line of the wind farm is the main line wiring mode, the equivalent impedance is:

${Z Z}_{eq eq__n no} = = [[{Σ Σ}_{i i = = 11}^{n no} {i i}^{22} {Z Z}_{i i}]] / / {n no}^{22} - - - - - - ((66));;$

在公式（6）中，Z_{eq_n}为电缆的等效阻抗，n为线路上机组台数，Z_i为第i条电缆的阻抗。In formula (6), Z _{eq_n} is the equivalent impedance of the cable, n is the number of units on the line, and Z _i is the impedance of the i-th cable.

2）当风电场内部集电线路的接线方式为多条分支线路连接到同一节点的接线方式时，等效阻抗为：2) When the wiring mode of the internal collector line of the wind farm is the wiring mode in which multiple branch lines are connected to the same node, the equivalent impedance is:

${Z Z}_{eq eq__n no} = = [[{Σ Σ}_{i i = = 11}^{n no} {n no}_{i i}^{22} {Z Z}_{i i}]] / / {[[{Σ Σ}_{i i = = 11}^{n no} {n no}_{i i}]]}^{22} - - - - - - ((77));;$

在公式（7）中，Z_{eq_n}为电缆的等效阻抗，n_m为每条线路上机组的台数，n为总的风机台数。In formula (7), Z _{eq_n} is the equivalent impedance of the cable, n _m is the number of units on each line, and n is the total number of fans.

进一步地，对于电缆线路的对地导纳支路，忽略风电场内的电压差异，等值对地导纳Y_eq等于等值前所有导纳Y_i支路的和，即：Further, for the ground-to-ground admittance branch of the cable line, ignoring the voltage difference in the wind farm, the equivalent ground-to-ground admittance Y _eq is equal to the sum of all admittance Y _i branches before the equivalent, that is:

${Y Y}_{eq eq} = = {Σ Σ}_{i i = = 11}^{m m} {Y Y}_{i i} - - - - - - ((88));;$

其中，i、m均为自然数。Among them, i and m are natural numbers.

本发明各实施例的双馈机组风电场聚合模型参数等值方法，由于主要包括：分别对双馈机组的发电机模型参数、轴系参数、变压器参数、风速进行等值处理，对风电场内部集电线路进行等值处理，整合各环节参数得到该双馈机组风电场的聚合模型；该模型仿真计算结果与实际运行情况的误差在可以接受的范围内，能够可靠反映风电场实际运行特性，可以用于对大规模风力发电的相关问题进行深入分析，在大规模风电集中并网情况下，对含大规模风电的电力系统分析计算；该模型可以克服现有技术中稳定性差、可靠性低和适用范围小的缺陷，以实现稳定性好、可靠性高和适用范围大的优点。The DFIG wind farm aggregation model parameter equivalence method in each embodiment of the present invention mainly includes: performing equivalent processing on the generator model parameters, shafting parameters, transformer parameters, and wind speed of the DFIG respectively; Equivalent processing is performed on the collector line, and the parameters of each link are integrated to obtain the aggregation model of the DFIG wind farm; the error between the simulation calculation results of the model and the actual operating conditions is within an acceptable range, and it can reliably reflect the actual operating characteristics of the wind farm. It can be used to conduct in-depth analysis on the related issues of large-scale wind power generation. In the case of large-scale wind power centralized grid connection, it can analyze and calculate the power system containing large-scale wind power; this model can overcome the poor stability and low reliability of the existing technology And the defects of small application range to achieve the advantages of good stability, high reliability and wide application range.

本发明的其它特征和优点将在随后的说明书中阐述，并且，部分地从说明书中变得显而易见，或者通过实施本发明而了解。Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention.

下面通过附图和实施例，对本发明的技术方案做进一步的详细描述。The technical solutions of the present invention will be described in further detail below with reference to the accompanying drawings and embodiments.

附图说明Description of drawings

附图用来提供对本发明的进一步理解，并且构成说明书的一部分，与本发明的实施例一起用于解释本发明，并不构成对本发明的限制。在附图中：The accompanying drawings are used to provide a further understanding of the present invention, and constitute a part of the description, and are used together with the embodiments of the present invention to explain the present invention, and do not constitute a limitation to the present invention. In the attached picture:

图1为本发明双馈机组风电场聚合模型参数等值方法中风电机组干线式接线部分的结构示意图；Fig. 1 is the structural schematic diagram of the main-line wiring part of the wind turbine in the method for equivalent value of the wind farm aggregation model parameters of the double-fed turbine of the present invention;

图2为本发明双馈机组风电场聚合模型参数等值方法中多个风电机组并行连接的结构示意图；Fig. 2 is the structure schematic diagram of parallel connection of a plurality of wind turbines in the double-fed turbine wind farm aggregation model parameter equivalence method of the present invention;

图3为本发明双馈机组风电场聚合模型参数等值方法的流程示意图。Fig. 3 is a schematic flowchart of a method for equivalent value of parameters of a wind farm aggregation model of a doubly-fed unit according to the present invention.

具体实施方式Detailed ways

以下结合附图对本发明的优选实施例进行说明，应当理解，此处所描述的优选实施例仅用于说明和解释本发明，并不用于限定本发明。The preferred embodiments of the present invention will be described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described here are only used to illustrate and explain the present invention, and are not intended to limit the present invention.

根据本发明实施例，如图1、图2和图3所示，提供了一种双馈机组风电场聚合模型参数等值方法。According to an embodiment of the present invention, as shown in FIG. 1 , FIG. 2 and FIG. 3 , a parameter equivalent method of an aggregation model of a doubly-fed unit wind farm is provided.

本实施例的双馈机组风电场聚合模型参数等值方法，主要包括以下步骤：The method for equivalent value of the wind farm aggregation model parameters of the DFIG in this embodiment mainly includes the following steps:

步骤1：对双馈机组发电机模型参数进行等值。Step 1: Equivalent to the generator model parameters of the doubly-fed unit.

步骤2：对双馈机组轴系参数进行等值。Step 2: Equivalent to the shafting parameters of the doubly-fed unit.

步骤3：对双馈机组变压器参数进行等值。Step 3: Equivalent to the transformer parameters of the doubly-fed unit.

在公式（3）中，S_{T_eq}为等效后的变压器容量；ST为变压器容量；Z_{T_eq}为等效后的变压器阻抗；ZT为变压器阻抗；m为风电机组台数。In formula (3), S _{T_eq} is the equivalent transformer capacity; ST is the transformer capacity; Z _{T_eq} is the equivalent transformer impedance; ZT is the transformer impedance; m is the number of wind turbines.

步骤4：对风速进行等值。Step 4: Equalize the wind speed.

如采用基于桨距角动作情况的分群法时，等效风速为：If the grouping method based on the action of the pitch angle is adopted, the equivalent wind speed is:

步骤5：对风电场内部集电线路进行等值。Step 5: Equivalent to the collector lines inside the wind farm.

由于风场接线方式不同，需要分情况讨论：Due to the different wiring methods of wind farms, it needs to be discussed according to the situation:

1）干线式接线结构，如图1所示。1) Trunk type wiring structure, as shown in Figure 1.

等值阻抗为：The equivalent impedance is:

2）多条分支线路连接到同一节点上，如图2所示。2) Multiple branch lines are connected to the same node, as shown in Figure 2.

则等值阻抗为：Then the equivalent impedance is:

在公式（7）中，Z_{eq_n}为电缆的等值阻抗，n_m为每条线路上机组的台数，n为总的风机台数。In formula (7), Z _{eq_n} is the equivalent impedance of the cable, n _m is the number of units on each line, and n is the total number of fans.

风电场内部集电线路分为电缆和架空线路2种，电缆的充电电容很大，一般为架空线路的20～25倍，相当于在线路中并联了无功补偿设备，而架空线路充电电容一般情况下可忽略。对于电缆线路的对地导纳支路，可以忽略风电场内的电压差异，等值对地导纳Y_eq等于等值前所有导纳Y_i支路的和，即：The internal collection lines of wind farms are divided into two types: cables and overhead lines. The charging capacitance of cables is very large, generally 20 to 25 times that of overhead lines, which is equivalent to parallel connection of reactive power compensation equipment in the line, while the charging capacitance of overhead lines is generally case can be ignored. For the ground-to-ground admittance branch of the cable line, the voltage difference in the wind farm can be ignored, and the equivalent ground-to-ground admittance Y _eq is equal to the sum of all admittance Y _i branches before the equivalent value, that is:

${Y Y}_{eq eq} = = {Σ Σ}_{i i = = 11}^{m m} {Y Y}_{i i} - - - - - - ((88));;$

其中，i、m均为自然数。Among them, i and m are natural numbers.

最后应说明的是：以上所述仅为本发明的优选实施例而已，并不用于限制本发明，尽管参照前述实施例对本发明进行了详细的说明，对于本领域的技术人员来说，其依然可以对前述各实施例所记载的技术方案进行修改，或者对其中部分技术特征进行等同替换。凡在本发明的精神和原则之内，所作的任何修改、等同替换、改进等，均应包含在本发明的保护范围之内。Finally, it should be noted that: the above is only a preferred embodiment of the present invention, and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, it still The technical solutions recorded in the foregoing embodiments may be modified, or some technical features thereof may be equivalently replaced. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. a double-fed unit wind energy turbine set polymerization model parameter equivalence method, it is characterized in that, mainly comprise: respectively double-fed unit carried out equivalence processing and wind energy turbine set inside current collection circuit carried out to equivalence and process, then integrating each link polymerization parameter, obtaining the polymerization model of this double-fed unit wind energy turbine set.

2. double-fed unit wind energy turbine set polymerization model parameter equivalence method according to claim 1, is characterized in that, the described operation of double-fed unit being carried out to equivalent processing, at least comprises:

A, to the generator model parameter of double-fed unit carry out equivalence process;

B, to the axle of double-fed unit be parameter carry out equivalence process;

C, to the transformer parameter of double-fed unit carry out equivalence process;

D, to the wind speed of double-fed unit carry out equivalence process.

3. double-fed unit wind energy turbine set polymerization model parameter equivalence method according to claim 2, is characterized in that, described step a, specifically comprises:

Suppose in the aerogenerator of n platform same model and have m platform equivalence to become 1 unit, equivalent calculation formula is as follows:

\{\begin{matrix} S_{eq} = Σ_{i = 1}^{m} S_{i} = mS, \\ P_{eq} = Σ_{i = 1}^{m} P_{i} = mP, Q_{eq} = Σ_{i = 1}^{m} Q_{i} = mQ \\ X_{m - eq} = \frac{x_{m}}{m} \\ X_{s - eq} = \frac{x_{s}}{m}, X_{r - eq} = \frac{x_{r}}{m}, \\ r_{s - eq} = \frac{r_{s}}{m}, r_{r - eq} = \frac{r_{s}}{m} \end{matrix} - - - (1);

In formula (1), S _eqrepresent equivalent generator capacity, S _irepresent i platform generator capacity; M is the wind turbine number of organizing a performance; P _eqrepresent the active power after equivalence; P _irepresent the active power of i platform unit; P represents the average active power of each unit; Q _eqrepresent the reactive power after equivalence; Q _irepresent the reactive power of i platform unit; Q represents the average reactive power of each unit; X _m-eqfor the generator excitation reactance after equivalence; x _mfor generator excitation reactance; X _s-eqfor the generator unit stator reactance after equivalence; x _sfor generator unit stator reactance; X _r-eqfor the generator amature reactance after equivalence; x _rfor generator amature reactance; r _s-eqfor the generator unit stator resistance after equivalence; r _sfor generator unit stator resistance; r _r-eqfor the generator amature resistance after equivalence; r _rfor generator amature resistance.

4. double-fed unit wind energy turbine set polymerization model parameter equivalence method according to claim 2, is characterized in that, in step b, described is that parameter is carried out equivalent formula and is to axle:

\{\begin{matrix} H_{g_eq} = Σ_{i = 1}^{m} H_{gi} = m H_{g} \\ H_{t_eq} = Σ_{i = 1}^{m} H_{ti} = m H_{t} \\ H_{s_eq} = Σ_{i = 1}^{m} H_{si} = m H_{s} \end{matrix} - - - (2);

In formula (2), H _{g_eq}for the generator amature inertia time constant after equivalence; H _gfor generator amature inertia time constant; H _{t_eq}for the wind mill rotor inertia time constant after equivalence; H _tfor wind mill rotor inertia time constant; K _{s_eq}for the axis rigidity coefficient after equivalence; K _sfor axis rigidity coefficient; M is the wind turbine number of organizing a performance.

5. double-fed unit wind energy turbine set polymerization model parameter equivalence method according to claim 2, is characterized in that, in step c, describedly transformer parameter is carried out to equivalent formula is.

\{\begin{matrix} S_{T_eq} = {mS}_{T} \\ Z_{T_eq} = \frac{Z_{T}}{m} \end{matrix} - - - (3);

In formula (3), S _{t_eq}for the transformer capacity after equivalence; S _tfor transformer capacity; Z _{t_eq}for the transformer impedance after equivalence; Z _tfor transformer impedance; M is the wind turbine number of organizing a performance.

6. double-fed unit wind energy turbine set polymerization model parameter equivalence method according to claim 2, is characterized in that, in steps d, described wind speed is carried out to equivalent operation, specifically comprises:

While adopting the grouping method based on propeller pitch angle action situation, equivalent wind speed is:

v_{eq} = \frac{1}{m} Σ_{i = 1}^{m} v_{i} - - - (4);

In formula (4), v _iit is the wind speed that i platform unit is captured; The mechanical output that polymerization model is caught is:

P_{m} = m (\frac{1}{2} ρ {AC}_{p \max} V_{eq}^{3}) - - - (5);

In formula (5), m is unit number of units, and ρ is wind power concentration, and A is unit wind sweeping area, C _pmaxfor maximal wind-energy usage factor, v _eqfor equivalent wind speed.

7. double-fed unit wind energy turbine set polymerization model parameter equivalence method according to claim 1, is characterized in that, the described operation of wind energy turbine set inside current collection circuit being carried out to equivalent processing, specifically comprises:

According to the mode of connection of wind energy turbine set inside current collection circuit, wind energy turbine set inside current collection circuit is waited to Value Operations, specifically comprise:

1) in the time that the mode of connection of the inner current collection circuit of wind energy turbine set is the trunk line type mode of connection, equivalent impedance is:

Z_{eq_n} = [Σ_{i = 1}^{n} i^{2} Z_{i}] / n^{2} - - - (6);

In formula (6), Z _{eq_n}for the equiva lent impedance of cable, n is unit number of units on circuit, Z _iit is the impedance of i bar of cable;

2) when the mode of connection of the inner current collection circuit of wind energy turbine set is many branched lines while being connected to the mode of connection of same node, equiva lent impedance is:

Z_{eq_n} = [Σ_{i = 1}^{n} n_{i}^{2} Z_{i}] / {[Σ_{i = 1}^{n} n_{i}]}^{2} - - - (7);

In formula (7), Z _{eq_n}for the equiva lent impedance of cable, n _mfor the number of units of unit on every circuit, n is total blower fan number of units.

8. double-fed unit wind energy turbine set polymerization model parameter equivalence method according to claim 7, is characterized in that, for the branch road of admittance over the ground of cable line, ignore the voltage differences in wind energy turbine set, equivalence is admittance Y over the ground _eqequal equivalent front all admittance Y _ibranch road and, that is:

Y_{eq} = Σ_{i = 1}^{m} Y_{i} - - - (8);

Wherein, i, m are natural number.