Receiving end power grid direct current drop point strong correlation pumped storage unit selection method and system, computer equipment and storage medium

Abstract

The invention discloses a receiving end power grid direct current drop point strong correlation pumped storage unit selection method, which comprises the following steps of: proposing reactive voltage indexes of a pumped storage unit and a direct current inverter bus from three dimensions of pumped storage unit grid-connected point system strength, direct current drop point system strength and an electrical distance between the pumped storage unit and a direct current drop point; the relative gain matrix is utilized to establish strong correlation pumped storage unit constraints of the direct current inverter bus, the maximum reactive power support of the pumped storage unit to the direct current inverter bus is taken as a target, a direct current drop point strong correlation pumped storage unit optimal selection model is established, and finally a direct current drop point strong correlation pumped storage unit selection optimization result is obtained. The result can effectively utilize the phase modulation capability of the pumped storage unit to ensure the safe and stable operation of the receiving-end power grid, effectively improve the reactive operation characteristics of the East China power grid, improve the system strength and voltage stability, and provide reference for the planned operation of the direct-current feed-in receiving-end power grid.

Description

Technical Field

[0001] The present invention belongs to the technical field of electric power systems, and in particular relates to a method, system, computer equipment and storage medium for selecting a pumped-storage unit with strong correlation with the DC drop point of a receiving-end power grid. Background Art

[0002] In addition to power generation and pumping conditions, pumped storage power station units also have power generation phase adjustment conditions and pumping phase adjustment conditions. These four conditions can generate reactive power to increase the grid voltage, and absorb reactive power to reduce the grid voltage. The phase adjustment capability of pumped storage units can play a role in regulating the system reactive power level and maintaining the system voltage constant, while avoiding the problem of excessive short-circuit current in the system caused by special phase regulators. Therefore, compared with the huge investment in special phase regulators, making full use of the reactive voltage support capability of existing pumped storage units has significant economic benefits, especially pumped storage units with electrical distance close to UHV DC converter stations, which can undertake the reactive voltage support task for the converter station.

[0003] At present, the vast majority of pumped-storage power stations have a relatively small number of phase-shifting operations and a relatively short duration, failing to give full play to the role of phase-shifting in the units. Only a small number of literatures have verified the feasibility of pumped-storage units providing reactive power support. For example, the literature [Wu Kuayu, Lu Cen Cen, Yuan Yazhou. Simulation study on the reactive voltage support of Binjin DC by phase-shifting operation of pumped-storage units [J]. China Electric Power, 2018, 51(03): 54-61] proposed an operation mode of using phase-shifting operation of adjacent pumped-storage units to provide reactive voltage support for UHV DC, and simulated and verified that under specific working conditions, the phase-shifting operation of adjacent pumped-storage units of Binjin DC in Zhejiang power grid can improve the reliability of DC operation and thus improve the safe operation level of Zhejiang power grid with multiple DC infeeds; the literature [Chen Daojun, Li Li, Xie Jiemin, et al. Analysis of the impact of phase-shifting operation of Heimifeng units on improving the transient voltage stability level of Hunan power grid [J]. Hunan Electric Power, 2021, 41(01): 98-102] studied the impact of phase-shifting operation of Heimifeng pumped-storage units in Hunan power grid on the transient voltage stability level of Hunan power grid. The simulation comparative analysis results show that the voltage stability level of Hunan power grid is effectively improved after the phase-shifting operation of Heimifeng pumped-storage units. However, the above studies only selected the DC and pumped storage units for testing based on the electrical distance, and there is no strong correlation selection method for DC pumped storage units.

[0004] In order to fully tap the phase adjustment capability of pumped-storage units, alleviate the reactive power regulation pressure of the receiving power grid, effectively improve the reactive operation characteristics of the receiving power grid, and improve the system strength and voltage stability, it is urgent to study the selection method of pumped-storage units with strong correlation of DC drop point in the receiving power grid considering the reactive power support of pumped storage. Summary of the invention

[0005] In view of the above, the present invention provides a method for selecting a pumped-storage unit with strong correlation with the DC drop point of the receiving-end power grid, which takes into account the reactive support capacity of the pumped-storage unit and can improve system strength and voltage stability.

[0006] A method for selecting a pumped-storage unit with strong correlation in DC drop point of a receiving-end power grid comprises: when any AC bus is disturbed, calculating the reactive voltage index between the pumped-storage unit and the DC inverter bus in the power grid system, and calculating a relative gain matrix based on the reactive voltage index; establishing an optimization target for selecting the pumped-storage unit with strong correlation in DC drop point of the receiving-end power grid according to the relative gain matrix; solving the optimization target under constraint conditions, so as to find the pumped-storage unit with the strongest correlation for each DC inverter bus; the constraint conditions include the constraint of the strongly correlated pumped-storage unit of the DC inverter bus and the reactive capacity constraint of the pumped-storage unit.

[0007] Furthermore, the reactive voltage index includes a voltage interaction factor, a voltage reactive sensitivity, and a reactive replacement factor, and the calculation expression is as follows:

[0008]

[0009] Among them: VIF ji is the voltage interaction factor between the DC inverter bus j and the pumped storage unit i, VRPS ji is the voltage reactive sensitivity between the DC inverter bus j and the pumped storage unit i, RPRF ji is the reactive power replacement factor between the DC inverter bus j and the pumped storage unit i, ΔU j and ΔU i are the voltage changes of the DC inverter bus j and the AC bus of the pumped storage unit i after the disturbance, ΔQ i is the change in reactive power injected by pumped storage unit i after the disturbance, ΔQ j It represents the equivalent local reactive power change that produces the same disturbance effect on the voltage of the DC inverter bus j. i and j are the numbers of the pumped-storage unit and the DC inverter bus, respectively. 1≤i≤M, 1≤j≤N, M and N are the numbers of the pumped-storage unit and the DC inverter bus in the power grid system, respectively.

[0010] Furthermore, the relative gain matrix expressions of the voltage interaction influence factor, voltage reactive sensitivity, and reactive replacement factor are as follows:

[0011]

[0012] Where: VIF Represents the relative gain matrix of voltage interaction factors, Λ VRPS Relative gain matrix representing voltage reactive sensitivity, ΛRPRF Relative gain matrix representing reactive power substitution factor, K VIF The coefficient matrix representing the voltage interaction factor, in which the element value of the jth row and the ith column is VIF ji ; K VRPS The coefficient matrix representing voltage reactive power sensitivity, the value of the element in the jth row and ith column of the matrix is ​​VRPS ji ; K RPRF The coefficient matrix represents the reactive power replacement factor. The element value of the jth row and the ith column in the matrix is ​​RPRF ji ; · represents the multiplication of corresponding elements of two matrices, and T represents transpose.

[0013] Furthermore, for any DC inverter bus j, the pumped storage unit i with the strongest correlation is found for it through the following optimization objectives;

[0014]

[0015] Where: Q sg,i is the reactive power output by pumped storage unit i, Λ VIF,ji ,Λ VPRF,ji ,Λ RPRF,ji are the relative gain matrices Λ VIF ,Λ VRPS ,Λ RPRF The value of the element in the j-th row and i-th column.

[0016] Furthermore, the expression of the strongly correlated pumped storage unit constraint is as follows:

[0017] Λ VIF,ji >K c,VIF , Λ VPRF,ji >K c,VPRF , Λ RPRF,ji >K c,RPRF

[0018] Where: VIF,ji ,Λ VPRF,ji ,Λ RPRF,ji are the relative gain matrices Λ VIF ,Λ VRPS ,Λ RPRF The value of the element in the jth row and ith column, K c,VIF , K c,VPRF , K c,RPRF They are the critical values ​​of relative gain coefficient of voltage interaction factor, voltage reactive sensitivity and reactive replacement factor respectively.

[0019] Furthermore, the expression of reactive capacity constraint of the pumped storage unit is as follows:

[0020] 0≤Q sg,i ≤Q sg,max,i

[0021] Where: Q sg,i is the reactive power output by pumped storage unit i, Q sg,max,i is the maximum reactive power that pumped storage unit i can output.

[0022] In a second aspect, the present invention provides a system for selecting a pumped-storage unit with strong correlation of DC drop point in a receiving-end power grid, which is used to execute the above-mentioned method for selecting a pumped-storage unit with strong correlation of DC drop point in a receiving-end power grid, and the selection system comprises:

[0023] A matrix calculation unit, for calculating a reactive voltage index between a pumped storage unit and a DC inverter bus in a power grid system when any AC bus is disturbed, and calculating a relative gain matrix based on the reactive voltage index;

[0024] A target construction unit, which establishes an optimization target for selecting a pumped-storage unit with strong correlation with the DC point of the receiving-end power grid according to the relative gain matrix;

[0025] The optimization solving unit is used to solve the optimization target under constraint conditions, so as to find the pumped storage unit with the strongest correlation for each DC inverter bus; the constraint conditions include the strongly correlated pumped storage unit constraint of the DC inverter bus and the reactive capacity constraint of the pumped storage unit.

[0026] Further, the matrix calculation unit calculates the reactive voltage index by the following expression, including voltage interaction influence factor, voltage reactive sensitivity, and reactive replacement factor;

[0027]

[0028] Among them: VIF ji is the voltage interaction factor between the DC inverter bus j and the pumped storage unit i, VRPS ji is the voltage reactive sensitivity between the DC inverter bus j and the pumped storage unit i, RPRF ji is the reactive power replacement factor between the DC inverter bus j and the pumped storage unit i, ΔU j and ΔU i are the voltage changes of the DC inverter bus j and the AC bus of the pumped storage unit i after the disturbance, ΔQ i is the change in reactive power injected by pumped storage unit i after the disturbance, ΔQ j It represents the equivalent local reactive power change that produces the same disturbance effect on the voltage of the DC inverter bus j. i and j are the numbers of the pumped-storage unit and the DC inverter bus, respectively. 1≤i≤M, 1≤j≤N, M and N are the numbers of the pumped-storage unit and the DC inverter bus in the power grid system, respectively.

[0029] Furthermore, the matrix calculation unit calculates the relative gain matrix by the following expression:

[0030]

[0031] Where: VIF Represents the relative gain matrix of voltage interaction factors, Λ VRPS Relative gain matrix representing voltage reactive sensitivity, Λ RPRF Relative gain matrix representing reactive power substitution factor, K VIF The coefficient matrix representing the voltage interaction factor, in which the element value of the jth row and the ith column is VIF ji ; K VRPS The coefficient matrix representing voltage reactive power sensitivity, the value of the element in the jth row and ith column of the matrix is ​​VRPS ji ; K RPRF The coefficient matrix represents the reactive power replacement factor. The element value of the jth row and the ith column in the matrix is ​​RPRF ji ; · represents the multiplication of corresponding elements of two matrices, and T represents transpose.

[0032] Further, for any DC inverter bus j, the target construction unit finds the pumped storage unit i with the strongest correlation for it by establishing the following optimization target;

[0033]

[0034] Where: Q sg,i is the reactive power output by pumped storage unit i, Λ VIF,ji ,Λ VPRF,ji ,Λ RPRF,ji are the relative gain matrices Λ VIF ,Λ VRPS ,Λ RPRF The value of the element in the j-th row and i-th column.

[0035] Furthermore, the optimization solving unit solves the above optimization objective under the following constraints:

[0036] Λ VIF,ji >K c,VIF , Λ VPRF,ji >K c,VPRF , Λ RPRF,ji >K c,RPRF

[0037] 0≤Q sg,i ≤Q sg,max,i

[0038] Where: VIF,ji ,Λ VPRF,ji ,Λ RPRF,ji are the relative gain matrices ΛVIF ,Λ VRPS ,Λ RPRF The value of the element in the jth row and ith column, K c,VIF , K c,VPRF , K c,RPRF are the relative gain coefficient critical values ​​of voltage interaction factor, voltage reactive sensitivity, and reactive replacement factor, respectively. sg,i is the reactive power output by pumped storage unit i, Q sg,max,i is the maximum reactive power that pumped storage unit i can output.

[0039] In a third aspect, the present invention provides a computer device, comprising a memory and a processor, wherein the memory stores a computer program, and the processor is used to execute the computer program to implement the above-mentioned method for selecting a pumped-storage unit with strong correlation with the DC drop point of the receiving-end power grid.

[0040] In a fourth aspect, the present invention provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the above-mentioned method for selecting a pumped-storage unit with strong correlation with the DC drop point of a receiving-end power grid.

[0041] The present invention considers the reactive support capability of the pumped-storage unit and proposes a method for selecting the pumped-storage unit with strong correlation to the DC drop point of the receiving-end power grid. The method proposes reactive voltage indicators of the pumped-storage unit and the DC inverter bus from three dimensions: the system strength of the pumped-storage unit grid connection point, the system strength of the DC drop point and the electrical distance between the pumped-storage unit and the DC drop point. The relative gain matrix is ​​used to establish the strong correlation pumped-storage unit constraint of the DC inverter bus. With the goal of maximizing the reactive support of the pumped-storage unit to the DC inverter bus, an optimal selection model for the pumped-storage unit with strong correlation to the DC drop point is established. Finally, the optimization result of the selection of the pumped-storage unit with strong correlation to the DC drop point is obtained. The obtained optimization result can effectively utilize the phase adjustment capability of the pumped-storage unit to ensure the safe and stable operation of the receiving-end power grid, effectively improve the reactive operation characteristics of the East China power grid, improve the system strength and voltage stability, and provide a reference for the planning and operation of the DC feed-in receiving-end power grid. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 Schematic diagram of the modified IEEE 39-node system grid topology in the verification example of the present invention.

[0043] Figure 2 It is a comparative schematic diagram of the jump voltage of the HVDC1 DC inverter bus before and after the strong correlation pumped storage unit participates in reactive power support in the verification example of the present invention.

[0044] Figure 3It is a comparative schematic diagram of the jump voltage of the HVDC2 DC inverter bus before and after the strong correlation pumped storage unit participates in reactive power support in the verification example of the present invention.

[0045] Figure 4 The present invention is a structural block diagram of the system for selecting pumped-storage units with strong correlation with the DC drop point of the receiving-end power grid.

[0046] Figure 5 The present invention is a schematic diagram of the structure of an electronic device implemented according to the method of the present invention. DETAILED DESCRIPTION

[0047] In order to describe the present invention more specifically, the technical solution of the present invention is described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0048] The method for selecting a pumped storage unit with strong correlation with the DC drop point of a receiving-end power grid of the present invention comprises the following steps:

[0049] (1) Establish reactive voltage indicators between pumped storage units and DC inverter busbars.

[0050] In a receiving-end power grid with multiple DC feeds, if the electrical distance between the pumped-storage unit and the DC drop point is far, it is difficult for the pumped-storage unit to support the DC; even if the electrical distance between the pumped-storage unit and the DC drop point is very close, but if the external system has a large system strength compared to the DC or pumped-storage unit, the role that pumped storage can play is also very small compared to the external system. At this time, the voltage support of the DC mainly comes from the external system, and pumped storage is difficult to change the operating characteristics of the DC. To this end, the present invention evaluates the coupling effect between the pumped-storage power station and the DC drop point from three perspectives.

[0051] 1.1 Voltage interaction factor.

[0052] According to the Jacobian matrix of the power flow balance equation, the analytical calculation method of the voltage interaction factor VIF (Voltage Interaction Factor) between any two buses can be derived. VIF can be defined as:

[0053]

[0054] Where: ΔU i , ΔU j are the voltage changes of DC inverter bus j and AC bus of pumped storage unit i respectively. If VIF is large, a disturbance in one AC bus will inevitably have a greater impact on the other bus; in the receiving-end power grid of pumped storage, a large VIF between the pumped storage unit and the DC drop point means that the electrical distance between the pumped storage unit and the DC drop point is relatively close, which can play a role in reactive power regulation.

[0055] 1.2 Voltage reactive power sensitivity.

[0056] The voltage interaction factor reflects the electrical distance between the pumped storage unit and the DC point, but whether the pumped storage unit can play a significant role in voltage support for the DC point also involves the issue of system strength; if the system strength at the DC point is very large, it means that the external AC system can play a good role in voltage support for the DC point, and the role of the pumped storage unit is insignificant. Therefore, it is difficult to fully reflect the reactive voltage coupling relationship between the pumped storage unit and the DC point by relying solely on the voltage interaction factor. The definition of voltage and reactive power sensitivity (VRPS) is given below:

[0057]

[0058] Where: ΔQ i is the change in reactive power injected into pumped storage unit i, ΔU j is the voltage change of the DC inverter bus j. If VRPS is large, then the reactive power compensation at one AC bus can produce a larger voltage support effect at another bus; in the receiving-end power grid of pumped storage, the large VRPS between the pumped storage unit and the DC drop point means that the voltage of the DC drop point can be adjusted by increasing the reactive output of the pumped storage unit.

[0059] 1.3 Reactive power replacement factor.

[0060] In order to more intuitively measure the effect of the reactive output of the pumped storage unit on the DC drop point, the reactive power replacement factor (RPRF) is further defined:

[0061]

[0062] Where: ΔQ i is the change in reactive power injected by pumped storage unit i after the disturbance, ΔQ j It is the equivalent local reactive power change that produces the same disturbance effect on the voltage of DC inverter bus j. The meaning of reactive substitution factor is that the increase of unit reactive power at bus i is equivalent to the increase of reactive power at bus j by RPRF. If RPRF is large, it means that the reactive compensation applied at one bus has the same effect on the voltage regulation of another bus, which is equivalent to the reactive compensation at the other bus.

[0063] (2) Establish the strongly correlated pumped storage unit constraints of the DC inverter bus.

[0064] In a multi-DC feed-in receiving-end power grid, for a specific DC drop point, the pumped storage units with strong correlation are found to provide voltage support for it, while the units with weak correlation are not considered to provide voltage support for the DC, so as to make more efficient use of the pumped storage unit resources. Therefore, the relative gain array (RGA) method is used to analyze the correlation between the DC drop point and the pumped storage unit.

[0065] Considering the terminal voltage of the pumped storage unit as input and the DC drop point voltage as output, a multi-input multi-output system based on voltage interaction factors can be established:

[0066] U LCC =K VIF U PS

[0067] Where: U LCC Represents the vector composed of the DC voltage amplitude, U PS Represents the vector of terminal voltage of pumped storage unit, K VIF The coefficient matrix representing the voltage interaction factors is expressed as follows:

[0068] K VIF (j,i)=VIF ji

[0069] Then the relative gain matrix based on the voltage interaction factor is:

[0070]

[0071] Where: VIF represents the relative gain matrix based on the VIF index, represents the multiplication of the corresponding elements of the two matrices; if K VIF The matrix is ​​not reversible, K VIF -1 The matrix can be selected as K VIF Pseudoinverse of a matrix.

[0072] Similarly, if the reactive power output of the pumped storage unit is regarded as the input and the DC drop point voltage is regarded as the output, a multi-input multi-output system based on voltage reactive power sensitivity can be established:

[0073] U LCC =K VRPS Q PS

[0074] Where: Q PS The vector representing the reactive power output of the pumped storage unit, K VRPS The coefficient matrix representing the voltage reactive power sensitivity composition, the element expression is:

[0075] K VRPS (j,i)=VRPS ji

[0076] Then the relative gain matrix based on voltage reactive sensitivity is:

[0077]

[0078] If the reactive power output of the pumped storage unit is regarded as the input and the DC drop voltage is regarded as the output, a multi-input multi-output system based on voltage-reactive sensitivity can be established:

[0079] Q LCC =K RPRF Q PS

[0080] Where: Q LCC Represents the vector of reactive power compensation at the DC point, K RPRF The coefficient matrix representing the reactive power replacement factor is expressed as follows:

[0081] K RPRF (j,i)=RPRF ji

[0082] Then the relative gain matrix based on the reactive power replacement factor is:

[0083]

[0084] According to the relative gain matrix, the following principles can be applied: ① When the relative gain of the channel is close to 1, for example, 0.8<λ ji <1.2, it indicates that the correlation effect of other channels on this channel is very small; ② When the relative gain is less than 0 or close to 0, it means that the use of this channel regulator cannot obtain a good control effect, or the variable selection of this channel is inappropriate and should be reselected; ③ When the relative gain is between 0.3 and 0.7 or greater than 1.5, it indicates that there is very serious coupling in the system, and it is necessary to consider decoupling design or adopt multivariable control system design method.

[0085] After obtaining the phase gain matrix under three different indicators, the voltage-reactive correlation between the pumped-storage unit and the DC drop point can be determined based on the phase gain matrix. The above three reactive voltage indicators are actually mappings of the three dimensions of the pumped-storage unit grid connection point system strength, the DC drop point system strength, and the electrical distance between the pumped-storage unit and the DC drop point. When and only when the coefficients in the relative gain matrix of the three indicators are large, the pumped-storage unit is identified as having a strong correlation with a certain DC, and the pumped-storage unit is regarded as a strong correlation unit of the DC system. Whether the electrical distance between the pumped-storage unit and the DC drop point is far, or the strength of the external system of the pumped-storage unit or the DC drop point is too large, the effect of using the pumped-storage unit to improve the DC drop point voltage stability will be deteriorated.

[0086] Therefore, the strong correlation pumped storage unit constraints of the DC inverter bus are established:

[0087] Λ VIF,ji >K c,VIF , Λ VPRF,ji >K c,VPRF , Λ RPRF,ji >K c,RPRF

[0088] Where: VIF,ji ,Λ VPRF,ji ,Λ RPRF,ji are the coefficients of the jth row and ith column in the relative gain matrix of VIF, VPRF, and RPRF indicators, respectively. c,VIF , K c,VPRF , K c,RPRF They are the critical values ​​of relative gain coefficients of VIF, VPRF and RPRF indicators respectively (can be 0 to 0.3).

[0089] (3) Establish reactive capacity constraints for pumped storage units.

[0090] Reactive capacity constraints of pumped storage units:

[0091] 0≤Q sg,i ≤Q sg,max,i

[0092] Where: Q sg,i is the reactive power output by pumped storage unit i, Q sg,max,i is the maximum reactive power that pumped storage unit i can output.

[0093] (4) Set the optimization objective for selecting pumped-storage units with strong correlation with the DC drop point of the receiving grid and solve it in combination with the above constraints.

[0094] The purpose of optimizing the selection of pumped storage units with strong correlation to the DC drop point of the receiving-end power grid is to find the pumped storage unit i with the strongest correlation for a certain DC inverter bus j, which can play the greatest reactive support role in DC voltage recovery; for this purpose, the optimization objective is expressed as follows:

[0095]

[0096] Where: Q sg,i is the reactive power output by pumped storage unit i, Λ VIF,ji ,Λ VPRF,ji ,Λ RPRF,ji are the relative gain matrices Λ VIF ,Λ VRPS ,Λ RPRF The element value of the j-th row and i-th column in ; for any DC inverter bus j (j=1,2,3,…,N), output the corresponding strongest correlation pumped storage unit i.

[0097] Verification Example

[0098] Next, we will conduct numerical analysis on a modified IEEE 39-node system to verify the correctness of the proposed method. Figure 1 As shown, two LCC-HVDC systems are added to the system, connected to bus 3# and 16# respectively. The main parameters of the two LCC-HVDC systems are shown in Table 1:

[0099] Table 1

[0100]

[0101] In this IEEE 39-node system, 30#, 33#, 35#, and 37# generators are selected as pumped storage units. The maximum reactive capacity and pumped storage-DC reactive voltage index of each pumped storage unit are shown in Table 2:

[0102] Table 2

[0103]

[0104] According to the relative gain matrix principle, the relative gain matrix of pumped storage-DC reactive voltage index can be calculated, as shown in Table 3:

[0105] Table 3

[0106]

[0107] According to the optimization model, it can be determined that the inverter bus strongly correlated pumped storage unit of HVDC1 is 30#, and the inverter bus strongly correlated pumped storage unit of HVDC2 is 35#.

[0108] In order to verify the correctness of the selection of the strongly correlated pumped storage units, the supporting role of the strongly correlated pumped storage units on the DC voltage is considered when the inverter bus of HVDC1 and HVDC2 is short-circuited. For the inverter bus 3# of HVDC1, when a short-circuit fault occurs in the bus, HVDC1 will be locked. At this time, the pumped storage unit 30# generates more reactive power to help the inverter bus recover better and faster; in this verification example, the strongly correlated pumped storage unit 30# continues to provide an additional 300MVar of reactive power support within the next 0.3s after the inverter bus short-circuit fault occurs, such as Figure 2 As shown in the figure, the jump voltage of the HVDC1 DC inverter bus can be effectively improved after the pumped storage unit participates in the reactive power support. For the inverter bus 16# bus of HVDC2, when a short circuit occurs in the bus, HVDC2 will be locked. At this time, the pumped storage unit 35# will generate more reactive power to help the inverter bus recover better and faster; in this verification example, the strongly correlated pumped storage unit 35# will continue to provide an additional 300MVar reactive power support in the next 0.3s after the inverter bus short circuit occurs, as shown in the figure. Figure 3 As shown, the jump voltage of the HVDC2 DC inverter busbar can be effectively improved after the pumped storage unit participates in reactive power support. By comparison, it can be seen that the strong correlation pumped storage unit optimization method of the receiving-end power grid DC inverter busbar of the present invention can effectively select the most effective strong correlation pumped storage unit for DC reactive power support.

[0109] like Figure 4 As shown, the embodiment of the present invention further provides a system for selecting a pumped storage unit with a strong correlation with the DC drop point of a receiving-end power grid, comprising:

[0110] A matrix calculation unit, for calculating a reactive voltage index between a pumped storage unit and a DC inverter bus in a power grid system when any AC bus is disturbed, and calculating a relative gain matrix based on the reactive voltage index;

[0111] The target construction unit establishes the optimization target of the selection of the pumped storage unit with strong correlation with the DC point of the receiving power grid according to the relative gain matrix;

[0112] The optimization solving unit is used to solve the optimization target under the constraint conditions, so as to find the pumped storage unit with the strongest correlation for each DC inverter bus; the constraint conditions include the strongly correlated pumped storage unit constraint of the DC inverter bus and the reactive capacity constraint of the pumped storage unit.

[0113] Specifically, the matrix calculation unit calculates the reactive voltage index by the following expressions, including the voltage interaction influence factor, the voltage reactive sensitivity, and the reactive replacement factor;

[0114]

[0115] Among them: VIF ji is the voltage interaction factor between the DC inverter bus j and the pumped storage unit i, VRPS ji is the voltage reactive sensitivity between the DC inverter bus j and the pumped storage unit i, RPRF ji is the reactive power replacement factor between the DC inverter bus j and the pumped storage unit i, ΔU j and ΔU i are the voltage changes of the DC inverter bus j and the AC bus of the pumped storage unit i after the disturbance, ΔQ i is the change in reactive power injected by pumped storage unit i after the disturbance, ΔQ j It represents the equivalent local reactive power change that produces the same disturbance effect on the voltage of the DC inverter bus j. i and j are the numbers of the pumped-storage unit and the DC inverter bus, respectively. 1≤i≤M, 1≤j≤N, M and N are the numbers of the pumped-storage unit and the DC inverter bus in the power grid system, respectively.

[0116] The matrix calculation unit calculates the relative gain matrix using the following expression:

[0117]

[0118] Where: VIF Represents the relative gain matrix of voltage interaction factors, Λ VRPS Relative gain matrix representing voltage reactive sensitivity, Λ RPRF Relative gain matrix representing reactive power substitution factor, K VIF The coefficient matrix representing the voltage interaction factor, in which the element value of the jth row and the ith column is VIF ji ; K VRPS The coefficient matrix representing voltage reactive power sensitivity, the value of the element in the jth row and ith column of the matrix is ​​VRPS ji ; K RPRF The coefficient matrix represents the reactive power replacement factor. The element value of the jth row and the ith column in the matrix is ​​RPRF ji ; · represents the multiplication of corresponding elements of two matrices, and T represents transpose.

[0119] For any DC inverter bus j, the target construction unit finds the most relevant pumped storage unit i for it by establishing the following optimization objectives;

[0120]

[0121] Where: Q sg,i is the reactive power output by pumped storage unit i, Λ VIF,ji ,Λ VPRF,ji ,Λ RPRF,jiare the relative gain matrices Λ VIF ,Λ VRPS ,Λ RPRF The value of the element in the j-th row and i-th column.

[0122] The optimization solving unit solves the above optimization objectives under the following constraints:

[0123] Λ VIF,ji >K c,VIF , Λ VPRF,ji >K c,VPRF , Λ RPRF,ji >K c,RPRF

[0124] 0≤Q sg,i ≤Q sg,max,i

[0125] Where: VIF,ji ,Λ VPRF,ji ,Λ RPRF,ji are the relative gain matrices Λ VIF ,Λ VRPS ,Λ RPRF The value of the element in the jth row and ith column, K c,VIF , K c,VPRF , K c,RPRF are the relative gain coefficient critical values ​​of voltage interaction factor, voltage reactive sensitivity, and reactive replacement factor, respectively. sg,i is the reactive power output by pumped storage unit i, Q sg,max,i is the maximum reactive power that pumped storage unit i can output.

[0126] Accordingly, the present invention also provides an electronic device, including a processor and a memory, the memory is used to store a computer program, and the processor is used to execute the computer program to implement the above-mentioned method for selecting a pumped storage unit with strong correlation with the DC drop point of the receiving-end power grid. Figure 5 The figure shows a hardware structure of any electronic device with data processing capability in which the system for selecting a pumped storage unit with strong correlation with the DC drop point of the receiving-end power grid provided by the embodiment of the present invention is located. Figure 5 In addition to the processor, memory and network interface shown, the electronic device with data processing capability in which the system in the embodiment is located may also include other hardware according to the actual function of the electronic device, which will not be described in detail.

[0127] Accordingly, the present invention also provides a computer-readable storage medium on which computer instructions are stored. When the instructions are executed by a processor, the above-mentioned method for selecting a pumped-storage unit with strong correlation to the DC drop point of the receiving-end power grid is implemented. The computer-readable storage medium can be an internal storage unit of the aforementioned electronic device with data processing capability, such as a hard disk or memory; or it can be other external storage devices, such as a plug-in hard disk, a smart memory card (SmartMedia Card, SMC), an SD card, a flash card (Flash Card), etc. equipped on the device. The computer-readable storage medium can also include both an internal storage unit of an electronic device with data processing capability and an external storage device, which is used to store computer programs and other programs and data required by the electronic device with data processing capability, and can also be used to temporarily store data that has been output or is to be output.

[0128] The above description of the embodiments is to facilitate the understanding and application of the present invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to the above embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments. Improvements and modifications made by those skilled in the art to the present invention based on the disclosure of the present invention should be within the protection scope of the present invention.

Claims

1. A method for selecting a pumped storage unit with strong correlation to the DC point of the receiving power grid, characterized in that: include: When any AC bus is disturbed, the reactive voltage index between the pumped storage unit and the DC inverter bus in the power grid system is calculated, and the relative gain matrix is ​​calculated based on the reactive voltage index; According to the relative gain matrix, an optimization target for selecting a pumped-storage unit with strong correlation to the DC drop point of the receiving-end power grid is established; The optimization objective is solved under constraint conditions to find the pumped storage unit with the strongest correlation for each DC inverter bus; the constraint conditions include the strongly correlated pumped storage unit constraint of the DC inverter bus and the reactive capacity constraint of the pumped storage unit.

2. The method for selecting a pumped storage unit with strong correlation to the DC point of the receiving-end power grid according to claim 1 is characterized in that: include: The reactive voltage index includes voltage interaction factor, voltage reactive sensitivity, and reactive replacement factor, and the calculation expression is as follows: Among them: VIF ji is the voltage interaction factor between the DC inverter bus j and the pumped storage unit i, VRPS ji is the voltage reactive sensitivity between the DC inverter bus j and the pumped storage unit i, RPRF ji is the reactive power replacement factor between the DC inverter bus j and the pumped storage unit i, ΔU j and ΔU i are the voltage changes of the DC inverter bus j and the AC bus of the pumped storage unit i after the disturbance, ΔQ i is the change in reactive power injected by pumped storage unit i after the disturbance, ΔQ j It represents the equivalent local reactive power change that produces the same disturbance effect on the voltage of the DC inverter bus j. i and j are the numbers of the pumped-storage unit and the DC inverter bus, respectively. 1≤i≤M, 1≤j≤N, M and N are the numbers of the pumped-storage unit and the DC inverter bus in the power grid system, respectively.

3. The method for selecting a pumped storage unit with strong correlation with the DC point of the receiving-end power grid according to claim 2 is characterized in that: include: The relative gain matrix expressions of the voltage interaction influence factor, voltage reactive sensitivity, and reactive replacement factor are as follows: Where: VIF Represents the relative gain matrix of voltage interaction factors, Λ VRPS Relative gain matrix representing voltage reactive sensitivity, Λ RPRF Relative gain matrix representing reactive power substitution factor, K VIF The coefficient matrix representing the voltage interaction factor, in which the element value of the jth row and the ith column is VIF ji ; K VRPS The coefficient matrix representing voltage reactive power sensitivity, the value of the element in the jth row and ith column of the matrix is ​​VRPS ji ; K RPRF The coefficient matrix represents the reactive power replacement factor. The element value of the jth row and the ith column in the matrix is ​​RPRF ji ; · represents the multiplication of corresponding elements of two matrices, and T represents transpose.

4. The method for selecting a pumped storage unit with strong correlation with the DC point of the receiving-end power grid according to claim 3 is characterized in that: It includes: for any DC inverter bus j, finding the pumped storage unit i with the strongest correlation for it through the following optimization objectives; Where: Q sg,i is the reactive power output by pumped storage unit i, Λ VIF,ji ,Λ VPRF,ji ,Λ RPRF,ji are the relative gain matrices Λ VIF ,Λ VRPS ,Λ RPRF The value of the element in the j-th row and i-th column.

5. The method for selecting a pumped storage unit with strong correlation to the DC point of the receiving-end power grid according to claim 1 is characterized in that: The expression of the strongly correlated pumped storage unit constraint is as follows: L VIF,ji >K c,VIF ,L VPRF,ji >K c,VPRF ,L RPRF,ji >K c,RPRF Where: VIF,ji ,Λ VPRF,ji ,Λ RPRF,ji are the relative gain matrices Λ VIF ,Λ VRPS ,Λ RPRF The value of the element in the jth row and ith column, K c,VIF , K c,VPRF , K c,RPRF They are the critical values ​​of relative gain coefficient of voltage interaction factor, voltage reactive sensitivity and reactive replacement factor respectively.

6. The method for selecting a pumped storage unit with strong correlation to the DC point of the receiving-end power grid according to claim 1, characterized in that: The expression of reactive capacity constraint of the pumped storage unit is as follows: 0≤Q sg,i ≤Q sg,max,i Where: Q sg,i is the reactive power output by pumped storage unit i, Q sg,max,i is the maximum reactive power that pumped storage unit i can output.

7. A system for selecting a pumped-storage unit with strong correlation of DC drop point in a receiving-end power grid, used for executing the method for selecting a pumped-storage unit with strong correlation of DC drop point in a receiving-end power grid as claimed in any one of claims 1 to 6, characterized in that: The selection system includes: A matrix calculation unit, for calculating reactive voltage index and relative gain matrix between the pumped storage unit and the DC inverter bus in the power grid system when any AC bus is disturbed; A target construction unit, which establishes an optimization target for selecting a pumped-storage unit with strong correlation with the DC point of the receiving-end power grid according to the relative gain matrix; The optimization solving unit is used to solve the optimization target under constraint conditions, so as to find the pumped storage unit with the strongest correlation for each DC inverter bus; the constraint conditions include the strongly correlated pumped storage unit constraint of the DC inverter bus and the reactive capacity constraint of the pumped storage unit.

8. The system for selecting pumped storage units with strong correlation to DC drop point of receiving power grid according to claim 7, characterized in that: include: The reactive voltage index includes voltage interaction factor, voltage reactive sensitivity, and reactive replacement factor, and the calculation expression is as follows: Among them: VIF ji is the voltage interaction factor between the DC inverter bus j and the pumped storage unit i, VRPS ji is the voltage reactive sensitivity between the DC inverter bus j and the pumped storage unit i, RPRF ji is the reactive power replacement factor between the DC inverter bus j and the pumped storage unit i, ΔU j and ΔU i are the voltage changes of the DC inverter bus j and the AC bus of the pumped storage unit i after the disturbance, ΔQ i is the change in reactive power injected by pumped storage unit i after the disturbance, ΔQ j It represents the equivalent local reactive power change that produces the same disturbance effect on the voltage of the DC inverter bus j. i and j are the numbers of the pumped-storage unit and the DC inverter bus, respectively. 1≤i≤M, 1≤j≤N, M and N are the numbers of the pumped-storage unit and the DC inverter bus in the power grid system, respectively.

9. A computer device comprising a memory and a processor, characterized in that: include: The memory stores a computer program, and the processor is used to execute the computer program to implement the method for selecting a pumped-storage unit with strong correlation with the DC drop point of the receiving-end power grid as claimed in any one of claims 1 to 6.

10. A computer-readable storage medium storing a computer program, characterized in that: include: When the computer program is executed by the processor, it implements the method for selecting a pumped-storage unit with strong correlation with the DC drop point of the receiving-end power grid as described in any one of claims 1 to 6.

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