Offshore wind power aggregation modeling method, system and medium for reactive power compensation configuration

Abstract

The present invention discloses an offshore wind power aggregate modeling method, system, and medium for reactive power compensation configuration. The method collects basic data from the wind farm to be modeled to obtain collected parameters. The collected parameters are used to calculate and summarize the active power loss, reactive power loss, and susceptance of all combined units, and the active power loss, reactive power loss, and susceptance are evenly divided into several branches. The parameters required for aggregate modeling of the branches, the parameters required for aggregate modeling of the wind turbine chassis transformer, and the parameters required for aggregate modeling of the submarine cable and offshore step-up transformer are then calculated to construct an aggregate model of the offshore wind power system. The present invention can perform aggregate modeling of wind farms, reducing the amount of repetitive and complex modeling work without affecting the reactive power compensation configuration results.

Description

Technical Field

[0001] The present invention belongs to the field of power systems, and in particular relates to an offshore wind power aggregation modeling method, system and medium for reactive compensation configuration based on PSD-BPA (Power System Analysis Program). Background Art

[0002] The current layout of offshore wind turbines utilizes a combined unit wiring scheme with 3 to 6 wind turbines on the high-voltage side. Each combined unit is connected to a 220kV booster station via a 35kV collector line. The booster station is equipped with one or two booster transformers, and one or two submarine cables are used to connect the station to land. Due to the large number of wind turbines, modeling each turbine individually would be a complex undertaking and would be ineffective for calculating reactive power compensation configuration. Therefore, aggregated modeling of the wind farm is required to reduce the repetitive and complex modeling workload without affecting the reactive power compensation configuration results. Summary of the Invention

[0003] The purpose of the present invention is to provide an offshore wind power aggregate modeling method, system and medium for reactive compensation configuration to address the defects of the prior art. The present invention can perform aggregate modeling of wind farms, reducing the repetitive and complicated modeling workload without affecting the reactive compensation configuration results.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] Offshore wind power aggregation modeling approach for reactive power compensation configuration, including:

[0006] Collect basic data of the wind farm to be modeled and obtain collection parameters;

[0007] The collected parameters are used to calculate and summarize the active power loss, reactive power loss, and susceptance of all combined units, and the active power loss, reactive power loss, and susceptance are evenly divided into several branches. The combined unit is the transmission line where multiple wind turbines in the wind farm work together, and the end of the transmission line is connected to the offshore boost transformer.

[0008] By dividing the active power loss, reactive power loss and susceptance data of each branch equally, the parameters required for branch aggregation modeling are calculated. The parameters required for wind turbine box transformer aggregation modeling are calculated based on the number of branches. The parameters required for submarine cable and offshore boost transformer aggregation modeling are calculated based on the collected parameters, and an aggregation model of the offshore wind power system is constructed.

[0009] Furthermore, the investment parameters include wind turbine type, single unit capacity, number of units, wind turbine chassis transformer related parameters, submarine cable related parameters and offshore boost transformer related parameters.

[0010] Furthermore, the collected parameters are used to calculate and summarize the active power loss, reactive power loss and susceptance of all the combined units, and the active power loss, reactive power loss and susceptance are evenly divided into several branches, specifically:

[0011] Calculate the active power loss, reactive power loss and susceptance of the combined unit using the collected parameters:

[0012]

[0013]

[0014]

[0015]

[0016]

[0017]

[0018]

[0019]

[0020]

[0021] I i =I i-1 +i i (10)

[0022]

[0023] Where, P loss Indicates the total active power loss of the combined unit; Q loss Indicates the total reactive power loss of the combined unit; B C Indicates the total susceptance of the combined unit; P I Indicates the total active power loss of each combined unit; Q I Represents the total reactive power loss of each combined unit; B CI represents the total susceptance of each combined unit; X CI represents the total capacitive reactance of each combined unit; P i represents the active power loss of the combined unit where the i-th parallel wind turbine is located; Q i I represents the reactive power loss of the combined unit where the i-th parallel wind turbine is located; i Indicates the current flowing through the combined unit where the i-th parallel fan is located; R i represents the resistance of the combined unit where the i-th parallel fan is located; X i is the inductive reactance of the combined unit where the i-th parallel fan is located; U is the line voltage; XCi is the capacitive reactance of the combined unit where the i-th parallel wind turbine is located; P wi is the active power of the i-th parallel wind turbine in the combined unit; i i is the current generated by the i-th parallel wind turbine in the combined unit; U 联合 is the line voltage of the combined unit; m is the number of combined units in the offshore wind farm;

[0024] The obtained P loss , Q loss 、B C Divide into several branches evenly, as shown below:

[0025]

[0026]

[0027]

[0028] Where, P d is the active power loss of each branch after equal division; Q d is the reactive power loss of each branch after equal division; B Cd is the charging power of each branch after equal division; n is the number of equal divisions.

[0029] Furthermore, the parameters required for aggregate modeling of the branches are calculated by equally dividing the active power loss, reactive power loss, and susceptance data of each branch, specifically:

[0030] By equally dividing the active power loss, reactive power loss, and susceptance data of each branch, the resistance, reactance, and susceptance of the branch are calculated. The resistance, reactance, and susceptance of the branch are normalized to obtain the parameters required for aggregate modeling of the branch. The calculation formula is as follows:

[0031]

[0032]

[0033]

[0034]

[0035]

[0036]

[0037] Where R d is the resistance of each branch after bisection; X Ld is the reactance of each branch after bisection; I d is the current of each branch after bisection; Rd* is the per-unit resistance value of each branch after bisection; X Ld* is the per-unit reactance value of each branch after bisection; B Cd* is the per-unit susceptance value of each branch after equal division; P is the active power delivered by each branch after equal division; S B Base capacity; U B is the voltage reference value.

[0038] Furthermore, the parameters required for the aggregate modeling of the wind turbine chassis transformer are calculated according to the number of branches, specifically: the per-unit leakage impedance of the wind turbine chassis transformer is calculated according to the number of branches, and the calculation formula is as follows:

[0039]

[0040]

[0041] Where, X w* is the per-unit value of leakage resistance of a single fan chassis; X Lw* Indicates n w After the wind turbines are merged into w units, the leakage reactance per unit value corresponding to the wind turbine box transformer is obtained, and w = n; Uk% is the impedance percentage; S w is the capacity of a single fan; n w is the total number of fans.

[0042] Furthermore, the parameters required for the aggregate modeling of the submarine cable and the offshore boost transformer are calculated by using the collected parameters, specifically: the per-unit value of the submarine cable resistance, per-unit value of the reactance, per-unit value of the susceptance, and per-unit value of the offshore boost transformer leakage reactance are calculated according to the collected parameters, and the calculation formula is as follows:

[0043]

[0044]

[0045]

[0046]

[0047]

[0048] Where R S* is the per-unit value of the submarine cable resistance; X LS* B is the per-unit value of submarine cable reactance; CS* is the per-unit value of submarine cable capacitance; X 1* X is the per-unit value of high-pressure side leakage resistance of offshore boost transformer; 2* is the per-unit leakage resistance of the offshore boost transformer; R is the resistance per unit length of the submarine cable; X L is the reactance per unit length of submarine cable; X C is the inductance per unit length of the submarine cable; LS is the length of the submarine cable; X (1-2) K is the transformer half-through reactance; f is the splitting coefficient; S T is the transformer capacity.

[0049] Offshore wind power aggregation modeling system for reactive power compensation configuration, including:

[0050] Data collection parameter acquisition module: used to collect basic data of the wind farm to be modeled and obtain data collection parameters;

[0051] Branch decomposition module: used to calculate and summarize the active power loss, reactive power loss and susceptance of all joint units using the collected parameters, and evenly divide the active power loss, reactive power loss and susceptance into several branches; the joint unit is the transmission line where multiple wind turbines in the wind farm work together, and the end of the transmission line is connected to the offshore boost transformer;

[0052] Model construction module: It is used to calculate the parameters required for branch aggregation modeling by dividing the active power loss, reactive power loss and electrical susceptance data of each branch equally. It also calculates the parameters required for wind turbine box transformer aggregation modeling based on the number of branches. It also calculates the parameters required for submarine cable and offshore boost transformer aggregation modeling based on the collected parameters, and constructs an aggregation model of the offshore wind power system.

[0053] Furthermore, in the investment parameter acquisition module, the investment parameters include wind turbine type, single unit capacity, number of units, wind turbine chassis transformer related parameters, submarine cable related parameters and offshore boost transformer related parameters.

[0054] Furthermore, in the branch decomposition module, the collected parameters are used to calculate and summarize the active power loss, reactive power loss and susceptance of all the combined units, and the active power loss, reactive power loss and susceptance are evenly divided into several branches, specifically:

[0055] Calculate the active power loss, reactive power loss and susceptance of the combined unit using the collected parameters:

[0056]

[0057]

[0058]

[0059]

[0060]

[0061]

[0062]

[0063] P i =3×I i 2 ×R i (8)

[0064] Q i =3×I i 2 ×X i (9)

[0065] I i =I i-1 +i i (10)

[0066]

[0067] Where, P loss Indicates the total active power loss of the combined unit; Q loss Indicates the total reactive power loss of the combined unit; B C Indicates the total susceptance of the combined unit; P I Indicates the total active power loss of each combined unit; Q I Represents the total reactive power loss of each combined unit; B CI represents the total susceptance of each combined unit; X CI represents the total capacitive reactance of each combined unit; P i represents the active power loss of the combined unit where the i-th parallel wind turbine is located; Q i I represents the reactive power loss of the combined unit where the i-th parallel wind turbine is located; i Indicates the current flowing through the combined unit where the i-th parallel fan is located; R i represents the resistance of the combined unit where the i-th parallel fan is located; X i is the inductive reactance of the combined unit where the i-th parallel fan is located; U is the line voltage; X Ci is the capacitive reactance of the combined unit where the i-th parallel wind turbine is located; P wi is the active power of the i-th parallel wind turbine in the combined unit; i i is the current generated by the i-th parallel wind turbine in the combined unit; U 联合 is the line voltage of the combined unit; m is the number of combined units in the offshore wind farm;

[0068] The obtained P loss , Q loss 、B C Divide into several branches evenly, as shown below:

[0069]

[0070]

[0071]

[0072] Where, P d is the active power loss of each branch after equal division; Q d is the reactive power loss of each branch after equal division; B Cd is the charging power of each branch after equal division; n is the number of equal divisions.

[0073] Furthermore, in the model building module:

[0074] By equally dividing the active power loss, reactive power loss, and susceptance data of each branch, the parameters required for branch aggregation modeling are calculated, specifically:

[0075] By equally dividing the active power loss, reactive power loss, and susceptance data of each branch, the resistance, reactance, and susceptance of the branch are calculated. The resistance, reactance, and susceptance of the branch are normalized to obtain the parameters required for aggregate modeling of the branch. The calculation formula is as follows:

[0076]

[0077]

[0078]

[0079]

[0080]

[0081]

[0082] Where R d is the resistance of each branch after bisection; X Ld is the reactance of each branch after bisection; I d is the current of each branch after bisection; R d* is the per-unit resistance value of each branch after bisection; X Ld* is the per-unit reactance value of each branch after bisection; B Cd* is the per-unit susceptance value of each branch after equal division; P is the active power delivered by each branch after equal division; S B Base capacity; U B is the voltage reference value;

[0083] Calculate the parameters required for aggregate modeling of the fan box transformer according to the number of branches. Specifically, calculate the per-unit leakage impedance of the fan box transformer according to the number of branches. The calculation formula is as follows:

[0084]

[0085]

[0086] Where, X w* is the per-unit value of leakage resistance of a single fan chassis; X Lw* Indicates n w After the wind turbines are merged into w units, the leakage reactance per unit value corresponding to the wind turbine box transformer is obtained, and w = n; Uk% is the impedance percentage; S w is the capacity of a single fan; n w is the total number of fans;

[0087] The parameters required for the aggregate modeling of the submarine cable and the offshore boost transformer are calculated using the collected data parameters. Specifically, the per-unit values ​​of the submarine cable resistance, reactance, and susceptance, as well as the per-unit value of the offshore boost transformer leakage reactance, are calculated based on the collected data parameters. The calculation formula is as follows:

[0088]

[0089]

[0090]

[0091]

[0092]

[0093] Where R S* is the per-unit value of the submarine cable resistance; X LS* B is the per-unit value of submarine cable reactance; CS* is the per-unit value of submarine cable capacitance; X 1* X is the per-unit value of high-pressure side leakage resistance of offshore boost transformer; 2* is the per-unit leakage resistance of the offshore boost transformer; R is the resistance per unit length of the submarine cable; X L is the reactance per unit length of submarine cable; X C is the inductance per unit length of the submarine cable; L S is the length of the submarine cable; X (1-2) K is the transformer half-through reactance; f is the splitting coefficient; S T is the transformer capacity.

[0094] A computer-readable storage medium stores a computer program, which, when executed by a processor, implements the steps of the offshore wind power aggregation modeling method for reactive power compensation configuration.

[0095] An electronic device comprises a memory, a processor and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the steps of the offshore wind power aggregation modeling method for reactive power compensation configuration are implemented.

[0096] Compared with the prior art, the present invention has the following beneficial technical effects:

[0097] The present invention proposes an offshore wind power aggregation modeling method for reactive compensation configuration. Based on the principle that the overall active power loss, reactive power loss and electrical susceptance of the offshore wind farm remain unchanged, the present invention redistributes the overall active power loss, reactive power loss and electrical susceptance of the offshore wind farm, and can perform aggregate modeling of the wind farm. On the basis of not affecting the reactive power compensation configuration results, the repetitive and complicated modeling workload is reduced, and simulation model support is provided for the subsequent reactive power compensation configuration of the offshore wind farm access system, so as to meet the requirements of reactive power local balance, power frequency overvoltage control and voltage control during operation, and provide technical support for offshore wind power grid connection projects. BRIEF DESCRIPTION OF THE DRAWINGS

[0098] The drawings in the specification are used to provide further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0099] Figure 1 Schematic diagram of offshore wind power aggregation modeling approach for reactive power compensation configuration;

[0100] Figure 2 Wiring diagram for each combined unit fan of 35kV line;

[0101] Figure 3 The simulation results are shown in the PSD-BPA geographical wiring diagram. DETAILED DESCRIPTION

[0102] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0103] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0104] Example 1

[0105] The present invention proposes an offshore wind power aggregation modeling method for reactive power compensation configuration.

[0106] The specific steps are as follows:

[0107] (1) Collect basic data of the wind farm to be modeled and obtain collection parameters;

[0108] (2) Calculate and summarize the active power loss, reactive power loss and susceptance of all combined units using the collected parameters, and divide the active power loss, reactive power loss and susceptance into multiple branches (generally divided into two or four);

[0109] (3) By dividing the active power loss, reactive power loss and susceptance of each branch equally, the resistance, reactance and susceptance of the branch are calculated and normalized to be used as the parameters required for the aggregate modeling of the branch;

[0110] (4) Calculate the per-unit leakage impedance of the wind turbine chassis transformer according to the number of branches, which is used as the parameter required for the aggregation modeling of the wind turbine chassis transformer;

[0111] (5) Calculate the per-unit value of resistance, per-unit value of reactance, per-unit value of susceptance of 220kV or higher voltage submarine cable and per-unit value of leakage reactance of offshore boost transformer by collecting the collected parameters, which are used as the parameters required for the aggregate modeling of submarine cable and offshore boost transformer;

[0112] (6) The aggregation model of the offshore wind power system is obtained based on the parameters required for the aggregation modeling of the branch, the parameters required for the aggregation modeling of the wind turbine box transformer, and the parameters required for the aggregation modeling of the submarine cable and the offshore boost transformer.

[0113] In the step (1): for the power system simulation software, basic data of the wind farm to be modeled is collected, including wind turbine type, single unit capacity, number of units, wind turbine chassis transformer related parameters, 35kV submarine cable parameters (model, field connection topology, length of each section, and resistance, reactance, and susceptance parameters per unit length), offshore step-up transformer related parameters, 220kV or higher voltage submarine cable parameters (model, length of each section, and resistance, reactance, and susceptance parameters per unit length);

[0114] In the step (2): calculating and summarizing the active power loss, reactive power loss, and susceptance of all the combined units according to the collected capital parameters, and evenly dividing them into two or four combined units;

[0115] Calculate the total active power loss, reactive power loss, and susceptance of the combined unit:

[0116]

[0117]

[0118]

[0119]

[0120]

[0121]

[0122]

[0123] P i =3×I i 2 ×R i (8)

[0124] Q i =3×I i 2 ×X i (9)

[0125] I i =I i-1 +i i (10)

[0126]

[0127] In the formula, the meanings of the variables are as follows:

[0128] P loss : Total active power loss of the combined unit, kW.

[0129] Q loss : Total reactive power loss of the combined unit, kvar.

[0130] B C : Total susceptance of the combined unit, S.

[0131] P I : Total active power loss of each combined unit, kW.

[0132] Q I : Total reactive power loss of each combined unit, kvar.

[0133] B CI : Total susceptance of each combined unit, S.

[0134] X CI : Total capacitive reactance of each combined unit, Ω.

[0135] P i : Active power loss of the combined unit where the i-th parallel wind turbine is located, kW.

[0136] Q i : Reactive power loss of the combined unit where the ith parallel wind turbine is located, kvar.

[0137] I i : The current flowing through the combined unit where the i-th parallel fan is located, A.

[0138] R i : resistance of the combined unit where the i-th parallel fan is located, Ω.

[0139] X i : The inductive reactance of the combined unit where the i-th parallel fan is located, Ω.

[0140] U: Line voltage, kV.

[0141] X Ci : Capacitive reactance of the combined unit where the i-th parallel fan is located, Ω.

[0142] P wi : Active power of the i-th parallel wind turbine in the combined unit, kW.

[0143] i i : The current generated by the i-th parallel wind turbine in the combined unit, A.

[0144] U 联合 : combined unit line voltage, kV.

[0145] m: Number of combined units in the offshore wind farm.

[0146] From formulas (1) to (10), we can see that the total active power loss of the combined unit P loss Equal to the total active power loss P of each combined unitI The total reactive power loss Q of the combined unit loss Equal to the total reactive power loss Q of each combined unit I The total capacitive reactance of the combined unit is X CI Equal to the total capacitive reactance X of each combined unit Ci The total active power loss of each combined unit P I Equal to the active power loss P of each parallel wind turbine in the combined unit i The total reactive power loss of each combined unit Q I Equal to the reactive power loss Q of each parallel wind turbine in the combined unit i The total capacitive reactance of each combined unit is X CI Equal to the capacitive reactance X of each parallel wind turbine in the combined unit Ci The sum of the active power loss P of each parallel wind turbine in the combined unit i , which is equal to the current I passing through the combined unit where each parallel fan is located i The product of the square of the resistance of the line section. The reactive power loss of each parallel wind turbine in the combined unit is Q i , which is equal to the current I passing through the combined unit where each parallel fan is located i The product of the square of and the inductive reactance of the line. The current I passing through the combined unit where the i-th parallel fan is located i Equal to the current i provided by the i-th fan i Add the current I passing through the combined unit where the i-1th parallel fan is located i-1 The current i generated by the i-th parallel fan in the combined unit i Equal to the active power P of the i-th parallel wind turbine wi Divide by the square root of three times the line voltage U.

[0147] The obtained P loss , Q loss 、B C Divide into multiple branches evenly.

[0148]

[0149]

[0150]

[0151] In the formula, the meanings of the variables are as follows:

[0152] P d : Active power loss of each branch after equal division, kW.

[0153] Q d: Reactive power loss of each branch after equal division, kvar.

[0154] B Cd : The susceptance of each branch after equal division, S.

[0155] n: The number of equal shares.

[0156] In the step (3), the resistance, reactance and susceptance values ​​of the branch are calculated by dividing the active power loss, reactive power loss and susceptance data of each branch equally and normalizing them;

[0157] Calculate the resistance, reactance, and susceptance of each branch and normalize them.

[0158]

[0159]

[0160]

[0161]

[0162]

[0163]

[0164] In the formula, the meanings of the variables are as follows:

[0165] R d : The resistance of each branch after bisection, Ω.

[0166] X Ld : The reactance of each branch after bisection, Ω.

[0167] I d : The current in each branch after equal division, A.

[0168] B Cd : The susceptance of each branch after equal division, S.

[0169] R d* : The per-unit resistance value of each branch after equal division.

[0170] X Ld* : The per-unit reactance value of each branch after equal division.

[0171] B Cd* : The per-unit value of the susceptance of each branch after equal division.

[0172] P: The active power transmitted by each branch after equal division.

[0173] S B : Basic capacity, 100MVA.

[0174] U B : Voltage reference value, kV.

[0175] In the step (4), the parameters required for aggregate modeling of the wind turbine chassis transformer are calculated according to the number of branches;

[0176]

[0177]

[0178] In the formula, the meanings of the variables are as follows:

[0179] X w* : Single fan chassis transformer leakage resistance per unit value.

[0180] X Lw* :n w After the wind turbines are merged into w units, the leakage reactance per unit value corresponding to the wind turbine box transformer is w=n.

[0181] Uk%: Impedance percentage.

[0182] S w : Capacity of a single fan, MVA.

[0183] S B : Base capacity, MVA.

[0184] n w : Total number of fans.

[0185] In the step (5), the submarine cable resistance, reactance, susceptance and leakage reactance of the offshore boost transformer are calculated by collecting the collected parameters;

[0186]

[0187]

[0188]

[0189]

[0190]

[0191] In the formula, the meanings of the variables are as follows:

[0192] R S* : Per unit value of submarine cable resistance.

[0193] X LS* : Per unit value of submarine cable reactance.

[0194] B CS* : Per unit value of submarine cable reactance.

[0195] X 1* : Per unit value of leakage resistance on high voltage side of boost transformer.

[0196] X 2* : Per unit value of leakage resistance on the low pressure side of the boost transformer.

[0197] R (Ω / km): resistance per unit length of submarine cable.

[0198] X L (Ω / km): Reactance per unit length of submarine cable.

[0199] X C (Ω / km): Inductance per unit length of submarine cable.

[0200] L S : Length of submarine cable.

[0201] X (1-2) : Transformer semi-through reactance.

[0202] K f : Splitting coefficient.

[0203] S T : Transformer capacity.

[0204] In the step (6), the reactive loss and charging power of the offshore wind power system are calculated based on the parameters required for the aggregate modeling of the branch, wind turbine box transformer, submarine cable and offshore boost transformer.

[0205] Q 充 =S B ×B * (27)

[0206] Q 损 =I * 2 ×X * ×S B (28)

[0207] Q 充 : System charging power, Mvar.

[0208] Q 损 : System reactive power loss, Mvar.

[0209] B * : Per unit value of susceptance.

[0210] X * : Reactance per unit value.

[0211] Application Examples

[0212] (1) Collect basic data of the wind farm to be modeled, including wind turbine type, single unit capacity, number of units, wind turbine box transformer related parameters, 35kV submarine cable parameters (model, field connection topology, length of each section, and resistance, reactance, and susceptance parameters per unit length), step-up transformer related parameters, and 220kV or higher voltage submarine cable parameters (model, length of each section, and resistance, reactance, and susceptance parameters per unit length).

[0213] (2) Calculate and summarize the active power loss, reactive power loss, and charging power of all combined units based on the collected capital parameters, and divide them equally into two or four combined units.

[0214] Table 1 Summary of active power loss, reactive power loss and total susceptance of combined unit 1

[0215]

[0216]

[0217] Table 2 Summary of active power loss, reactive power loss and total susceptance of combined unit 2

[0218]

[0219] Table 3 Summary of active power loss, reactive power loss and total susceptance of combined unit 3

[0220]

[0221] Table 4 Summary of active power loss, reactive power loss and total susceptance of combined unit 4

[0222]

[0223]

[0224] Table 5 Summary of active power loss, reactive power loss and total susceptance of combined unit 5

[0225]

[0226] Table 6 Summary of active power loss, reactive power loss and total susceptance of joint unit 6

[0227]

[0228] Table 7 New branch statistics

[0229]

[0230] (3) By dividing the active power loss, reactive power loss, susceptance and other data of each branch equally, calculate the resistance, reactance and susceptance values ​​of the branch and standardize them.

[0231] Table 8 Statistics of per unit value

[0232]

[0233] (4) Performing aggregate modeling on the wind turbine box transformer according to the number of branches to obtain the parameters required for aggregate modeling of the wind turbine box transformer;

[0234] This project has a total of 32 wind turbines, including one 13.6MW, one 8.5MW, and thirty 6MW. The impedance percentages of the three types of wind turbines are 8%, 10.5%, and 9%, respectively. According to formula (20), the per-unit leakage reactance values ​​of the three types of wind turbines are calculated to be 0.476190476, 1.166666667, and 1.417322835, respectively. According to formula (21), when the number of branches after merging is 2, the leakage reactance of the merged single wind turbine chassis is 0.086254965.

[0235] (5) The per-unit value of resistance, per-unit value of reactance, per-unit value of susceptance of 220kV or higher voltage submarine cable and per-unit value of leakage reactance of offshore boost transformer are calculated by collecting the parameters, which are used as the parameters required for the aggregate modeling of submarine cable and offshore boost transformer.

[0236] This project laid a single-circuit submarine cable with a total length of 51 km. The submarine cable parameters are shown in Table 9, and the offshore boost transformer parameters are shown in Table 10.

[0237] Table 9 Submarine cable parameters

[0238]

[0239] Table 10 Offshore pressure variation parameters

[0240]

[0241]

[0242] According to formulas (22) to (26), the relevant parameters in Table 11 can be obtained.

[0243] Table 11 Converted parameters of submarine cables and offshore boost transformers

[0244]

[0245] (6) The parameters required for the aggregation modeling of branches, wind turbine box transformers, submarine cables and offshore boost transformers are used to calculate the reactive loss and charging power of the offshore wind power system. The aggregation model of the offshore wind power system is simulated, and the simulation results are compared with the calculated reactive loss and charging power to verify the accuracy of the modeling.

[0246] The theoretical reactive power value of the wind farm is calculated according to formulas (27) and (28), as shown in Table 12.

[0247] Table 12 Converted parameters of submarine cables and offshore boost transformers

[0248]

[0249] By calculating the numerical value, the model is built in PSD-BPA software and simulated. The simulation results are as follows: Figure 2 shown. Figure 2 The reactive power loss of a single wind turbine is about 8.2Mvar, which is approximately equal to the theoretical calculated value of 8.62Mvar. The simulation results show that after the 35kV system undergoes offshore boosting and transformation, the reactive power is -40.4Mvar, which is approximately equal to the theoretical calculated value of -42.92Mvar. The modeling is accurate.

[0250] (7) Modeling completed.

[0251] Example 2

[0252] Offshore wind power aggregation modeling system for reactive power compensation configuration, including:

[0253] The data acquisition module is used to collect basic data of the wind farm to be modeled and obtain data parameters; the data acquisition parameters include wind turbine type, single unit capacity, number of units, wind turbine box transformer related parameters, submarine cable related parameters and offshore boost transformer related parameters.

[0254] Branch decomposition module: used to calculate and summarize the active power loss, reactive power loss and susceptance of all joint units using the collected parameters, and evenly divide the active power loss, reactive power loss and susceptance into several branches; the joint unit is the transmission line where multiple wind turbines in the wind farm work together, and the end of the transmission line is connected to the offshore boost transformer;

[0255] Specifically:

[0256] First, the active power loss, reactive power loss and susceptance of the combined unit are calculated using the collected parameters:

[0257]

[0258]

[0259]

[0260]

[0261]

[0262]

[0263]

[0264] P i=3×I i 2 ×R i (8)

[0265] Q i =3×I i 2 ×X i (9)

[0266] I i =I i-1 +i i (10)

[0267]

[0268] Where, P loss Indicates the total active power loss of the combined unit; Q loss Indicates the total reactive power loss of the combined unit; B C Indicates the total susceptance of the combined unit; P I Indicates the total active power loss of each combined unit; Q I Represents the total reactive power loss of each combined unit; B CI represents the total susceptance of each combined unit; X CI represents the total capacitive reactance of each combined unit; P i represents the active power loss of the combined unit where the i-th parallel wind turbine is located; Q i I represents the reactive power loss of the combined unit where the i-th parallel wind turbine is located; i Indicates the current flowing through the combined unit where the i-th parallel fan is located; R i represents the resistance of the combined unit where the i-th parallel fan is located; X i is the inductive reactance of the combined unit where the i-th parallel fan is located; U is the line voltage; X Ci is the capacitive reactance of the combined unit where the i-th parallel wind turbine is located; P wi is the active power of the i-th parallel wind turbine in the combined unit; i i is the current generated by the i-th parallel wind turbine in the combined unit; U 联合 is the line voltage of the combined unit; m is the number of combined units in the offshore wind farm;

[0269] Then, the obtained P loss , Q loss 、B C Divide into several branches evenly, as shown below:

[0270]

[0271]

[0272]

[0273] Where, P d is the active power loss of each branch after equal division; Q d is the reactive power loss of each branch after equal division; B Cd is the charging power of each branch after equal division; n is the number of equal divisions.

[0274] Model building module: This module is used to calculate the parameters required for branch aggregation modeling by dividing the active power loss, reactive power loss, and susceptance data of each branch equally. The parameters required for wind turbine chassis-based modeling are calculated based on the number of branches. The parameters required for submarine cable and offshore boost transformer aggregation modeling are calculated based on the collected parameters, thereby obtaining an aggregate model for the offshore wind power system.

[0275] The active power loss, reactive power loss, and susceptance data of each branch are divided equally to calculate the branch resistance, reactance, and susceptance. The branch resistance, reactance, and susceptance are then normalized to obtain the parameters required for aggregate modeling of the branch. The calculation formula is as follows:

[0276]

[0277]

[0278]

[0279]

[0280]

[0281]

[0282] Where R d is the resistance of each branch after bisection; X Ld is the reactance of each branch after bisection; I d is the current of each branch after bisection; R d* is the per-unit resistance value of each branch after bisection; X Ld* is the per-unit reactance value of each branch after bisection; B Cd* is the per-unit susceptance value of each branch after equal division; P is the active power delivered by each branch after equal division; S B Base capacity; U B is the voltage reference value;

[0283] Calculate the parameters required for aggregate modeling of the fan box transformer according to the number of branches. Specifically, calculate the per-unit leakage impedance of the fan box transformer according to the number of branches. The calculation formula is as follows:

[0284]

[0285]

[0286] Where, X w* is the per-unit value of leakage resistance of a single fan chassis; X Lw* Indicates n w After the wind turbines are merged into w units, the leakage reactance per unit value corresponding to the wind turbine box transformer is obtained, and w = n; Uk% is the impedance percentage; S w is the capacity of a single fan; n w is the total number of fans.

[0287] The parameters required for the aggregate modeling of the submarine cable and the offshore boost transformer are calculated using the collected data parameters. Specifically, the per-unit values ​​of the submarine cable resistance, reactance, and susceptance, as well as the per-unit value of the offshore boost transformer leakage reactance, are calculated based on the collected data parameters. The calculation formula is as follows:

[0288]

[0289]

[0290]

[0291]

[0292]

[0293] Where R S* is the per-unit value of the submarine cable resistance; X LS* B is the per-unit value of submarine cable reactance; CS* is the per-unit value of submarine cable capacitance; X 1* X is the per-unit value of high-pressure side leakage resistance of offshore boost transformer; 2* is the per-unit leakage resistance of the offshore boost transformer; R is the resistance per unit length of the submarine cable; X L is the reactance per unit length of submarine cable; X C is the inductance per unit length of the submarine cable; L S is the length of the submarine cable; X (1-2) K is the transformer half-through reactance; f is the splitting coefficient; S T is the transformer capacity.

[0294] It will be understood by those skilled in the art that embodiments of the present invention may be provided as methods, systems, or computer program products. Thus, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0295] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowcharts and / or block diagrams, as well as combinations of processes and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowcharts and / or block diagrams. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0296] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0297] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0298] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit its scope of protection. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field should understand that after reading the present invention, those skilled in the art may still make various changes, modifications or equivalent substitutions to the specific implementation methods of the invention, but these changes, modifications or equivalent substitutions are all within the scope of protection of the pending claims of the invention.

Claims

1. Offshore wind power aggregation modeling method for reactive power compensation configuration, characterized in that: include: Collect basic data of the wind farm to be modeled and obtain collection parameters; The collected parameters are used to calculate and summarize the active power loss, reactive power loss, and susceptance of all combined units, and the active power loss, reactive power loss, and susceptance are evenly divided into several branches. The combined unit is the transmission line where multiple wind turbines in the wind farm work together, and the end of the transmission line is connected to the offshore boost transformer. By equally dividing the active power loss, reactive power loss, and susceptance data of each branch, the parameters required for branch aggregation modeling are calculated. The parameters required for wind turbine box transformer aggregation modeling are calculated based on the number of branches. The parameters required for submarine cable and offshore boost transformer aggregation modeling are calculated based on the collected parameters, and an aggregation model of the offshore wind power system is constructed. The resistance, reactance, and susceptance of each branch are calculated by dividing the active power loss, reactive power loss, and susceptance data of each branch equally. The resistance, reactance, and susceptance of the branch are then normalized to obtain the parameters required for aggregate modeling of the branch. Calculate the per-unit leakage impedance of the fan box transformer according to the number of branches, and obtain the parameters required for the aggregation modeling of the fan box transformer; The per-unit value of submarine cable resistance, reactance, and susceptance as well as the per-unit value of offshore boost transformer leakage reactance are calculated based on the collected parameters, and the parameters required for aggregate modeling of submarine cable and offshore boost transformer are obtained.

2. The offshore wind power aggregation modeling method for reactive power compensation configuration according to claim 1, characterized in that: The investment parameters include wind turbine type, single unit capacity, number of units, wind turbine box transformer related parameters, submarine cable related parameters and offshore boost transformer related parameters.

3. The offshore wind power aggregation modeling method for reactive power compensation configuration according to claim 1, characterized in that: The collected parameters are used to calculate and summarize the active power loss, reactive power loss and susceptance of all the combined units, and the active power loss, reactive power loss and susceptance are evenly divided into several branches, specifically: Calculate the active power loss, reactive power loss and susceptance of the combined unit using the collected parameters: P i =3×I i 2 ×R i (8) Q i =3×I i 2 ×X i (9) I i =I i-1 +i i (10) Where, P loss Indicates the total active power loss of the combined unit; Q loss Indicates the total reactive power loss of the combined unit; B C Indicates the total susceptance of the combined unit; P I Indicates the total active power loss of each combined unit; Q I Represents the total reactive power loss of each combined unit; B CI represents the total susceptance of each combined unit; X CI represents the total capacitive reactance of each combined unit; P i represents the active power loss of the combined unit where the i-th parallel wind turbine is located; Q i I represents the reactive power loss of the combined unit where the i-th parallel wind turbine is located; i Indicates the current flowing through the combined unit where the i-th parallel fan is located; R i represents the resistance of the combined unit where the i-th parallel fan is located; X i is the inductive reactance of the combined unit where the i-th parallel fan is located; U is the line voltage; X Ci is the capacitive reactance of the combined unit where the i-th parallel wind turbine is located; P wi is the active power of the i-th parallel wind turbine in the combined unit; i i is the current generated by the i-th parallel wind turbine in the combined unit; U 联合 is the line voltage of the combined unit; m is the number of combined units in the offshore wind farm; The obtained P loss , Q loss 、B C Divide into several branches evenly, as shown below: Where, P d is the active power loss of each branch after equal division; Q d is the reactive power loss of each branch after equal division; B Cd is the susceptance of each branch after equal division; n is the number of equal divisions.

4. The offshore wind power aggregation modeling method for reactive power compensation configuration according to claim 3, characterized in that: The active power loss, reactive power loss and susceptance data of each branch after bisection are used to calculate the resistance, reactance and susceptance of the branch, and the resistance, reactance and susceptance of the branch are normalized to obtain the parameters required for aggregate modeling of the branch. The calculation formula is as follows: Where R d is the resistance of each branch after bisection; X Ld is the reactance of each branch after bisection; I d is the current of each branch after bisection; R d* is the per-unit resistance value of each branch after bisection; X Ld* is the per-unit reactance value of each branch after bisection; B Cd* is the per-unit susceptance value of each branch after equal division; P is the active power delivered by each branch after equal division; S B Base capacity; U B is the voltage reference value.

5. The offshore wind power aggregation modeling method for reactive power compensation configuration according to claim 4, characterized in that: The calculation formula for calculating the per-unit leakage resistance of the fan box transformer according to the number of branches is as follows: Where, X w* is the per-unit value of leakage resistance of a single fan chassis; X Lw* Indicates n w After the wind turbines are merged into w units, the leakage reactance per unit value corresponding to the wind turbine box transformer is obtained, and w = n; Uk% is the impedance percentage; S w is the capacity of a single fan; n w is the total number of fans.

6. The offshore wind power aggregation modeling method for reactive power compensation configuration according to claim 5, characterized in that: The calculation formula for calculating the per-unit value of submarine cable resistance, per-unit value of reactance, per-unit value of susceptance and per-unit value of leakage reactance of offshore boost transformer is as follows: Where R S* is the per-unit value of the submarine cable resistance; X LS* B is the per-unit value of submarine cable reactance; CS* is the per-unit value of submarine cable capacitance; X 1* X is the per-unit value of high-pressure side leakage resistance of offshore boost transformer; 2* is the per-unit leakage resistance of the offshore boost transformer; R is the resistance per unit length of the submarine cable; X L is the reactance per unit length of submarine cable; X C is the inductance per unit length of the submarine cable; L S is the length of the submarine cable; X (1-2) K is the transformer half-through reactance; f is the splitting coefficient; S T is the transformer capacity.

7. Offshore wind power aggregation modeling system for reactive power compensation configuration, characterized in that: include: Data collection parameter acquisition module: used to collect basic data of the wind farm to be modeled and obtain data collection parameters; Branch decomposition module: used to calculate and summarize the active power loss, reactive power loss and susceptance of all joint units using the collected parameters, and evenly divide the active power loss, reactive power loss and susceptance into several branches; the joint unit is the transmission line where multiple wind turbines in the wind farm work together, and the end of the transmission line is connected to the offshore boost transformer; Model building module: This module is used to calculate the parameters required for branch aggregation modeling by dividing the active power loss, reactive power loss, and susceptance data of each branch equally. The module also calculates the parameters required for wind turbine chassis-based modeling based on the number of branches. The module also calculates the parameters required for submarine cable and offshore boost transformer aggregation modeling based on the collected parameters, thereby constructing an aggregate model for the offshore wind power system. The resistance, reactance, and susceptance of each branch are calculated by dividing the active power loss, reactive power loss, and susceptance data of each branch equally. The resistance, reactance, and susceptance of the branch are then normalized to obtain the parameters required for aggregate modeling of the branch. Calculate the per-unit leakage impedance of the fan box transformer according to the number of branches, and obtain the parameters required for the aggregation modeling of the fan box transformer; The per-unit value of submarine cable resistance, reactance, and susceptance as well as the per-unit value of offshore boost transformer leakage reactance are calculated based on the collected parameters, and the parameters required for aggregate modeling of submarine cable and offshore boost transformer are obtained.

8. The offshore wind power aggregation modeling system for reactive power compensation configuration according to claim 7, characterized in that: In the investment parameter acquisition module, the investment parameters include wind turbine type, single unit capacity, number of units, wind turbine chassis transformer related parameters, submarine cable related parameters and offshore boost transformer related parameters.

9. The offshore wind power aggregation modeling system for reactive power compensation configuration according to claim 7, characterized in that: In the branch decomposition module, the collected parameters are used to calculate and summarize the active power loss, reactive power loss and susceptance of all the combined units, and the active power loss, reactive power loss and susceptance are evenly divided into several branches, specifically: Calculate the active power loss, reactive power loss and susceptance of the combined unit using the collected parameters: P i =3×I i 2 ×R i (8) Q i =3×I i 2 ×X i (9) I i =I i-1 +i i (10) Where, P loss Indicates the total active power loss of the combined unit; Q loss Indicates the total reactive power loss of the combined unit; B C Indicates the total susceptance of the combined unit; P I Indicates the total active power loss of each combined unit; Q I Represents the total reactive power loss of each combined unit; B CI represents the total susceptance of each combined unit; X CI represents the total capacitive reactance of each combined unit; P i represents the active power loss of the combined unit where the i-th parallel wind turbine is located; Q i I represents the reactive power loss of the combined unit where the i-th parallel wind turbine is located; i Indicates the current flowing through the combined unit where the i-th parallel fan is located; R i represents the resistance of the combined unit where the i-th parallel fan is located; X i is the inductive reactance of the combined unit where the i-th parallel fan is located; U is the line voltage; X Ci is the capacitive reactance of the combined unit where the i-th parallel wind turbine is located; P wi is the active power of the i-th parallel wind turbine in the combined unit; i i is the current generated by the i-th parallel wind turbine in the combined unit; U 联合 is the line voltage of the combined unit; m is the number of combined units in the offshore wind farm; The obtained P loss , Q loss 、B C Divide into several branches evenly, as shown below: Where, P d is the active power loss of each branch after equal division; Q d is the reactive power loss of each branch after equal division; B Cd is the susceptance of each branch after equal division; n is the number of equal divisions.

10. The offshore wind power aggregation modeling system for reactive power compensation configuration according to claim 9, characterized in that: In the model building module: By equally dividing the active power loss, reactive power loss, and susceptance data of each branch, the resistance, reactance, and susceptance of the branch are calculated. The resistance, reactance, and susceptance of the branch are normalized to obtain the parameters required for aggregate modeling of the branch. The calculation formula is as follows: Where R d is the resistance of each branch after bisection; X Ld is the reactance of each branch after bisection; I d is the current of each branch after bisection; R d* is the per-unit resistance value of each branch after bisection; X Ld* is the per-unit reactance value of each branch after bisection; B Cd* is the per-unit susceptance value of each branch after equal division; P is the active power delivered by each branch after equal division; S B Base capacity; U B is the voltage reference value; Calculate the per-unit leakage resistance of the fan box transformer according to the number of branches. The calculation formula is as follows: Where, X w* is the per-unit value of leakage resistance of a single fan chassis; X Lw* Indicates n w After the wind turbines are merged into w units, the leakage reactance per unit value corresponding to the wind turbine box transformer is obtained, and w = n; Uk% is the impedance percentage; S w is the capacity of a single fan; n w is the total number of fans; The per-unit value of submarine cable resistance, per-unit value of reactance, per-unit value of susceptance and per-unit value of offshore step-up transformer leakage reactance are calculated based on the collected parameters. The calculation formula is as follows: Where R S* is the per-unit value of the submarine cable resistance; X LS* B is the per-unit value of submarine cable reactance; CS* is the per-unit value of submarine cable capacitance; X 1* X is the per-unit value of high-pressure side leakage resistance of offshore boost transformer; 2* is the per-unit leakage resistance of the offshore boost transformer; R is the resistance per unit length of the submarine cable; X L is the reactance per unit length of submarine cable; X C is the inductance per unit length of the submarine cable; L S is the length of the submarine cable; X (1-2) K is the transformer half-through reactance; f is the splitting coefficient; S T is the transformer capacity.

11. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the steps of the offshore wind power aggregation modeling method for reactive power compensation configuration as claimed in any one of claims 1 to 6 are implemented.

12. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the computer program, the steps of the offshore wind power aggregation modeling method for reactive power compensation configuration as described in any one of claims 1 to 6 are implemented.

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