CN104009493A - Photovoltaic power generation unit group equivalent modeling method based on characteristic distances - Google Patents

Abstract

The invention belongs to the technical field of photovoltaic power generation, and particularly relates to a photovoltaic power generation unit group equivalent modeling method based on characteristic distances. The method comprises the steps that firstly, all power generation units in a photovoltaic power station are numbered, and inverter parameters in each power generation unit are read; secondly, the trace sensitivity of the inverter parameters in one power generation unit is calculated and a column vector is constituted; thirdly, the characteristic distances among all the power generation units are calculated; fourthly, all power generation units serve as main units in sequence, the sum of the characteristic distances between each main unit and all the other power generation units is calculated; fifthly, the main unit with the smallest characteristic distance is selected as a main power generation unit; sixthly, the inverter parameters in the main power generation unit serve as parameters of a photovoltaic power generation unit group equivalent machine, and the rated capacity of the equivalent machine is modified into the sum of the rated capacity of all the power generation units in a group. The equivalent modeling method is distinct in physical conception and improves equivalent modeling accuracy.

Description

A kind of photovoltaic generation unit group equivalent modeling method based on characteristic distance

Technical field

The invention belongs to photovoltaic power generation technology field, be specifically related to a kind of photovoltaic generation unit group equivalent modeling method based on characteristic distance.

Background technology

In recent years, the grid-connected solar power generation of China presents great-leap-forward development.According to national new forms of energy development plan, by 2015, China's grid-connected photovoltaic power generation installed capacity will reach 3,500 ten thousand kilowatts.In west area, the hours of daylight is long and dry short of rain, and solar energy resources is very abundant, and oneself has built many large-scale photovoltaics power station.After large-scale photovoltaic plant access electrical network, the fluctuation of photovoltaic generation power output will exert an influence to power network safety operation.In order to analyze the impact of grid-connected photovoltaic power station on electrical network, in the urgent need to setting up suitable photovoltaic plant model.

Large-sized photovoltaic power station floor space is large, conventionally by tens of extremely hundreds of photovoltaic generation units, is formed in parallel, and the installed capacity in power station can reach hundreds of megawatts.When setting up photovoltaic plant model, a kind of method is to the modeling respectively of each photovoltaic generation unit, then according to electric connecting relation, forms complete power station detailed model.This modeling method is corresponding one by one with actual power unit, model One's name is legion, and it is very complicated that power station model will become.When carrying out large-scale power system analytical calculation, if adopt detailed model computational efficiency very low, emulation length consuming time, and may cause the accuracy of computational convergence variation influence result of calculation.

Another kind method is the thinking that adopts equivalent modeling, first photovoltaic plant is hived off, and the generator unit that several dynamic response characteristics are close forms a photovoltaic generation unit group.For photovoltaic generation unit group, the electrical structure of each generator unit is similar, photovoltaic arrays, inverter and unit step-up transformer, consists of.If can simulate group response characteristic of interior all generator units by an Equivalent Model, so just can utilize equivalent generator unit model to substitute detailed model, photovoltaic generation unit group model is carried out to equivalent depression of order, improve simulation efficiency.The key of modeling is just photovoltaic generation unit group to carry out modeling accurately.

Summary of the invention

In order to overcome the defect of prior art, the object of the invention is to propose a kind of for simplifying the photovoltaic generation unit group equivalent modeling method based on characteristic distance of photovoltaic generation unit group model.

Equivalent modeling method of the present invention is achieved by the following technical solution:

A photovoltaic generation unit equivalent modeling method based on characteristic distance, the method comprises the steps:

Step 1, each generator unit in photovoltaic plant is numbered, reads the parameter of inverter in each generator unit;

Step 2, calculate the trace sensitivity of inverter parameter in a generator unit and form a column vector;

Step 3, calculate the characteristic distance between all generator units;

Step 4, using each generator unit successively as master unit, calculate respectively the characteristic distance sum between each master unit and all the other all generator units;

The master unit of step 5, selection characteristic distance sum minimum is as leading generator unit;

Step 6, the parameter using the parameter of inverter in leading generator unit as the equivalent machine of photovoltaic generation unit group, and the rated capacity of this equivalence machine is revised as to the rated capacity sum of group interior each generator unit, complete the foundation of photovoltaic generation unit group Equivalent Model.

In described step 1, in each generator unit, the parameter of inverter includes the direct voltage PI controller parameter K of inverter _pv, K _ivwith reactive power PI controller parameter K _pq, K _iq.

In described step 2, by the column vector described in the trace sensitivity formula composed as follows of inverter parameter in a generator unit

$\stackrel{\text{\→}}{S}=\left[\begin{array}{c}{S}_1\\ S_2\\ S_3\\ S_4\end{array}\right]$

In formula, s ₁-s ₄it is respectively the trace sensitivity of inverter parameter in a generator unit.

In described step 3, the step of calculating characteristic distance between all generator units comprises:

Step 31, the parameter of inverter in each generator unit is formed to a row vector;

Step 32, according to a column vector and each row vector, calculate the characteristic distance between every two generator units.

In described step 31, the parameter by inverter in each generator unit forms as shown in the formula described row vector

$\stackrel{\→}{V}=[K_{\mathrm{pv}},K_{\mathrm{iv}},K_{\mathrm{pq}},K_{\mathrm{iq}}]$

In formula, K _pv, K _iv, K _pq, K _iqparameter for inverter.

In described step 32, by following formula, calculate the characteristic distance between every two generator units:

$\begin{array}{c}{L}_{V_1-V_2}=|{({\stackrel{\→}{V}}_1-{\stackrel{\→}{V}}_2)}^T\×\stackrel{\→}{s}|\\ =|{[\left[\begin{array}{c}{K}_{\mathrm{pv}1}\\ K_{\mathrm{iv}1}\\ K_{\mathrm{pq}1}\\ K_{\mathrm{iq}1}\end{array}\right]-\left[\begin{array}{c}{K}_{\mathrm{pv}2}\\ K_{\mathrm{iv}2}\\ K_{\mathrm{pq}2}\\ K_{\mathrm{iq}2}\end{array}\right]]}^T\×\left[\begin{array}{c}{s}_1\\ s_2\\ s_3\\ s_4\end{array}\right]|\end{array}$

In formula, for the row vector that inverter parameter in first generator unit forms, K _pv1, K _iv1, K _pq1, K _iq1parameter for inverter in first generator unit; be the row vector that in second generator unit, inverter parameter forms, K _pv2, K _iv2, K _pq2, K _iq2it is the parameter of inverter in second generator unit.

In described step 4, by following formula, calculate the characteristic distance sum between each master unit and all the other all generator units:

$C_i=\underset{j=1}{\overset{n}{\mathrm{\Σ}}}{L}_{i-j}$

In formula, C _ibe the characteristic distance sum between i master unit and all the other n-1 generator unit, L _i-jbe the characteristic distance between i master unit and j generator unit, n is the sum of generator unit in photo-voltaic power generation station.

In described step 6, by following formula, the rated capacity of this equivalence machine is revised as to the rated capacity sum of group interior each generator unit:

$S_{\mathrm{eql}}=\underset{j=1}{\overset{n}{\mathrm{\Σ}}}{S}_j$

In formula, S _eq1for the rated capacity of equivalent machine, S _jfor the rated capacity of generator unit j, n is the sum of generator unit in photo-voltaic power generation station.

Compared with prior art, beneficial effect of the present invention is:

The characteristic distance of equivalent modeling method of the present invention based between each generator unit, selects leading generator unit, and then builds photovoltaic generation unit group's Equivalent Model, and clear physics conception has improved the precision of equivalent modeling.

Accompanying drawing explanation

Fig. 1 is the structural representation of photovoltaic plant in embodiment.

Fig. 2 is the schematic flow sheet of equivalent modeling method of the present invention.

Specific embodiment

Below in conjunction with accompanying drawing, to the present invention is based on the photovoltaic generation unit group equivalent modeling method of characteristic distance, be described in further detail.

Photovoltaic plant shown in Fig. 1 comprises 3 photovoltaic generation unit groups altogether, below according to the equivalent modeling method shown in Fig. 2, photovoltaic generation unit group 1 is carried out to equivalent modeling, comprises the steps:

Step 1, generator unit group 1 include 10 generator units, and each photovoltaic generation unit is distinguished to called after generator unit 1 according to order from small to large, generator unit 2, and generator unit 3 ..., generator unit 10; Read respectively the parameter of inverter in each generator unit, in each generator unit, inverter parameter includes the direct voltage PI controller parameter K of inverter _pv, K _ivwith reactive power PI controller parameter K _pq, K _iq;

In step 2, this example, select generator unit 1 and calculate its inverter parameter K _pv1, K _iv1, K _pq1, K _iq1trace sensitivity, the trace sensitivity of generator unit 1 is formed to a column vector

$\stackrel{\text{\→}}{S}=\left[\begin{array}{c}{S}_1\\ S_2\\ S_3\\ S_4\end{array}\right]---\left(1\right)$

In formula (1), s ₁, s ₂, s ₃, s ₄respectively four parameter K _pv1, K _iv1, K _pq1, K _iq1trace sensitivity;

Step 3, calculate the characteristic distance between all generator units, detailed process is as follows:

Step 31) by generator unit 1 ... in generator unit 10, the parameter group of inverter becomes row vector ?

$\begin{array}{c}{\stackrel{\→}{V}}_1=[K_{\mathrm{pv}1},K_{\mathrm{iv}1},K_{\mathrm{pq}1},K_{\mathrm{iq}1}]\\ {\stackrel{\→}{V}}_2=[K_{\mathrm{pv}2},K_{\mathrm{iv}2},K_{\mathrm{pq}2},K_{\mathrm{iq}2}]\\ \·\·\·\·\·\·\\ {\stackrel{\→}{V}}_{10}=[K_{\mathrm{pv}10,}{K}_{\mathrm{iv}10},K_{\mathrm{pq}10},K_{\mathrm{iq}10}]\end{array}---\left(2\right)$

Step 32) calculate the characteristic distance between generator unit 1 and generator unit 2 parameter vectors,

$\begin{array}{c}{L}_{V_1-V_2}=|{({\stackrel{\→}{V}}_1-{\stackrel{\→}{V}}_2)}^T\×\stackrel{\→}{s}|\\ =|{[\left[\begin{array}{c}{K}_{\mathrm{pv}1}\\ K_{\mathrm{iv}1}\\ K_{\mathrm{pq}1}\\ K_{\mathrm{iq}1}\end{array}\right]-\left[\begin{array}{c}{K}_{\mathrm{pv}2}\\ K_{\mathrm{iv}2}\\ K_{\mathrm{pq}2}\\ K_{\mathrm{iq}2}\end{array}\right]]}^T\×\left[\begin{array}{c}{s}_1\\ s_2\\ s_3\\ s_4\end{array}\right]|=|\underset{i=1}{\overset{4}{\mathrm{\Σ}}}(V_{1i}-V_{2i})\×s_i|\end{array}---\left(3\right)$

In formula (3), i=1,2,3,4, V _1ii parameter in generator unit 1 row vector, V _2ii parameter in generator unit 2 row vectors, s _iit is the trace sensitivity of i parameter;

Step 33) repeating step 32, by formula (3), calculate the characteristic distance between all generator units, calculate respectively the distance between generator unit 1 and generator unit 2,3,4,5,6,7,8,9,10, calculate the distance between generator unit 2 and generator unit 1,3,4,5,6,7,8,9,10, the like, and supplementary following table 1.

Table 1 characteristic distance

Step 4, using each generator unit successively as master unit, calculate respectively the characteristic distance sum between each master unit and all the other all generator units, detailed process is:

Step 41) first using generator unit 1 as master unit, by following formula, calculate generator unit 1 and all the other generator units 2,3 ..., the characteristic distance sum C between 10 ₁:

$C_1=\underset{j=2}{\overset{10}{\mathrm{\Σ}}}{L}_{1-j}---\left(4\right)$

Step 42) repeating step 41, pass through respectively calculate the characteristic distance sum C of all the other all generator units ₂, C ₃..., C _n, calculate respectively the distance sum C between generator unit 2 and generator unit 1,3,4,5,6,7,8,9,10 ₂, the distance sum C of calculating generator unit 3 and generator unit 1,2,4,5,6,7,8,9,10 ₃, the like, and supplementary following table 2.

Table 2 characteristic distance sum

Step 5, according to the size order of characteristic distance sum, be arranged in order, select the generator unit 3 of characteristic distance sum minimum as leading generator unit;

Step 6, direct voltage PI controller parameter K that will leading generator unit _pv3, K _iv3with reactive power PI controller parameter K _pq3, K _iq3as equivalent machine parameter of the photovoltaic generation unit group 1, the rated capacity S of equivalent machine 1 of while _ep1(5) are revised as group interior each generator unit rated capacity sum according to the following formula:

$S_{\mathrm{eql}}=\underset{j=1}{\overset{10}{\mathrm{\Σ}}}{S}_j---\left(5\right)$

Carry out above steps, can complete photovoltaic generation unit group 1 modeling, for generator unit group 2 and group 3, have similar modeling method with group 1, repeat no more herein.

Finally should be noted that: above embodiment is only in order to illustrate the application's technical scheme but not restriction to its protection range; although the application is had been described in detail with reference to above-described embodiment; those of ordinary skill in the field are to be understood that: those skilled in the art still can carry out all changes, revise or be equal to replacement to the embodiment of application after reading the application; these change, revise or be equal to replacement, within the claim scope that it all awaits the reply in its application.

Claims (8)

1. the photovoltaic generation unit equivalent modeling method based on characteristic distance, is characterized in that, the method comprises the steps:

Step 1, each generator unit in photovoltaic plant is numbered, reads the parameter of inverter in each generator unit;

Step 2, calculate the trace sensitivity of inverter parameter in a generator unit and form a column vector;

Step 3, calculate the characteristic distance between all generator units;

Step 4, using each generator unit successively as master unit, calculate respectively the characteristic distance sum between each master unit and all the other all generator units;

The master unit of step 5, selection characteristic distance sum minimum is as leading generator unit;

Step 6, the parameter using the parameter of inverter in leading generator unit as the equivalent machine of photovoltaic generation unit group, and the rated capacity of this equivalence machine is revised as to the rated capacity sum of group interior each generator unit, complete the foundation of photovoltaic generation unit group Equivalent Model.

2. the photovoltaic generation unit equivalent modeling method based on characteristic distance according to claim 1, is characterized in that, in described step 1, in each generator unit, the parameter of inverter includes the direct voltage PI controller parameter K of inverter _pv, K _ivwith reactive power PI controller parameter K _pq, K _iq.

3. the photovoltaic generation unit equivalent modeling method based on characteristic distance according to claim 1, is characterized in that, in described step 2, by the column vector described in the trace sensitivity formula composed as follows of inverter parameter in a generator unit

$\stackrel{\text{\→}}{S}=\left[\begin{array}{c}{S}_1\\ S_2\\ S_3\\ S_4\end{array}\right]$

In formula, s ₁-s ₄it is respectively the trace sensitivity of inverter parameter in a generator unit.

4. the photovoltaic generation unit equivalent modeling method based on characteristic distance according to claim 1, is characterized in that, in described step 3, the step of calculating characteristic distance between all generator units comprises:

Step 31, the parameter of inverter in each generator unit is formed to a row vector;

Step 32, according to a column vector and each row vector, calculate the characteristic distance between every two generator units.

5. the photovoltaic generation unit equivalent modeling method based on characteristic distance according to claim 4, is characterized in that, in described step 31, the parameter by inverter in each generator unit forms as shown in the formula described row vector

$\stackrel{\→}{V}=[K_{\mathrm{pv}},K_{\mathrm{iv}},K_{\mathrm{pq}},K_{\mathrm{iq}}]$

In formula, K _pv,k _iv,k _pq,k _iqparameter for inverter.

6. the photovoltaic generation unit equivalent modeling method based on characteristic distance according to claim 4, is characterized in that, in described step 32, by following formula, calculates the characteristic distance between every two generator units:

$\begin{array}{c}{L}_{V_1-V_2}=|{({\stackrel{\→}{V}}_1-{\stackrel{\→}{V}}_2)}^T\×\stackrel{\→}{s}|\\ =|{[\left[\begin{array}{c}{K}_{\mathrm{pv}1}\\ K_{\mathrm{iv}1}\\ K_{\mathrm{pq}1}\\ K_{\mathrm{iq}1}\end{array}\right]-\left[\begin{array}{c}{K}_{\mathrm{pv}2}\\ K_{\mathrm{iv}2}\\ K_{\mathrm{pq}2}\\ K_{\mathrm{iq}2}\end{array}\right]]}^T\×\left[\begin{array}{c}{s}_1\\ s_2\\ s_3\\ s_4\end{array}\right]|\end{array}$

In formula, for the row vector that inverter parameter in first generator unit forms, K _pv1, K _iv1,k _pq1, K _iq1parameter for inverter in first generator unit; be the row vector that in second generator unit, inverter parameter forms, K _pv2, K _iv2, K _pq2, K _iq2it is the parameter of inverter in second generator unit.

7. the photovoltaic generation unit equivalent modeling method based on characteristic distance according to claim 1, is characterized in that, in described step 4, by following formula, calculates the characteristic distance sum between each master unit and all the other all generator units:

$C_i=\underset{j=1}{\overset{n}{\mathrm{\Σ}}}{L}_{i-j}$

In formula, C _ibe the characteristic distance sum between i master unit and all the other n-1 generator unit, L _i-jbe the characteristic distance between i master unit and j generator unit, n is the sum of generator unit in photo-voltaic power generation station.

8. the photovoltaic generation unit equivalent modeling method based on characteristic distance according to claim 1, is characterized in that, in described step 6, by following formula, the rated capacity of this equivalence machine is revised as to the rated capacity sum of group interior each generator unit:

$S_{\mathrm{eql}}=\underset{j=1}{\overset{n}{\mathrm{\Σ}}}{S}_j$

In formula, S _eq1for the rated capacity of equivalent machine, S _jfor the rated capacity of generator unit j, n is the sum of generator unit in photo-voltaic power generation station.