A network-configuration type reactive power compensation device configuration method and system

Abstract

The application discloses a network-constructing type reactive power compensation device configuration method and system, relates to the technical field of voltage safety evaluation and reactive power compensation planning configuration of a new energy grid-connected system, and comprises the following steps: acquiring system parameters of a new energy collection system; obtaining a node impedance matrix when no network-constructing type reactive power compensation device is configured, calculating a transient voltage contribution vector of each target node and forming a multi-source transient voltage contribution vector; and identifying a same-direction superposition risk source set for transient overvoltage of the target node; generating a target cancellation voltage vector in the opposite direction of the same-direction superposition direction according to the transient voltage over-limit amount of the target node and the combined contribution vector of the same-direction superposition risk source set; constructing a device programmable equivalent model according to the network-constructing type reactive power compensation device; and obtaining a configuration scheme based on a configuration optimization model based on the target cancellation voltage vector after the network-constructing type reactive power compensation device is configured. The application reduces the combined amount of the voltage contribution vector after configuration and meets the transient overvoltage limit value.

Description

Technical Field

[0001] This invention relates to the field of voltage safety assessment and reactive power compensation planning and configuration technology for new energy grid-connected systems, specifically to a method and system for configuring a grid-type reactive power compensation device. Background Technology

[0002] With the large-scale integration of renewable energy sources such as wind and solar power into the AC grid after centralized collection, the sending-end system is gradually exhibiting characteristics such as low short-circuit capacity, weak synchronous support, high proportion of power electronics, and complex dynamic reactive power processes. When AC faults are cleared, DC blocking occurs, commutation fails, line reclosing occurs, or renewable energy units recover from faults, renewable energy power plants, filters, capacitors, and dynamic reactive power compensation equipment may generate reactive power surplus in a short period of time. If this reactive power surplus is transmitted to the grid connection point or common collection bus through the weak AC network impedance, it can easily lead to transient overvoltages.

[0003] Existing reactive power compensation device configuration methods typically focus on increasing short-circuit capacity, reducing equivalent impedance, meeting steady-state voltage deviation constraints, or verifying transient voltage peak values ​​through time-domain simulation. While these methods can reflect the strength of the system and the supporting role of the device after its connection to some extent, they have the following drawbacks: First, they often describe transient overvoltage risks using scalar indicators, making it difficult to reflect the superposition relationship of voltage contribution vectors from different risk sources in terms of amplitude and phase. Second, they often simplify network-type reactive power compensation devices to fixed short-circuit capacity or fixed reactive power capacity, failing to fully utilize the adjustable characteristics of voltage source reference values, virtual impedance, and current limiting features of network-type devices. Third, they are often configured based on the degree of node voltage exceeding limits, impedance sensitivity, or minimum capacity principle, making it difficult to explain why the configured device can offset a dominant risk source or a group of co-current superimposed risk sources. Fourth, for systems with multiple new energy power plants, filters, capacitors, and DC disturbances acting together, it is difficult to distinguish local reactive power risks, cross-site coupling risks, and co-current superimposed risks on common channels using only single-node indicators.

[0004] In view of the above, this application is hereby submitted. Summary of the Invention

[0005] To address at least one deficiency in existing reactive power compensation device configuration methods in the background art, this invention provides a grid-type reactive power compensation device configuration method and system. This invention no longer uses only short-circuit ratio, impedance ratio, or voltage over-limit amplitude as the configuration basis. Instead, it first calculates the complex transient voltage contribution vector (i.e., multi-source transient voltage contribution vector) formed at the target node after different risk sources are transferred by the network impedance. Then, it identifies a set of risk sources with large amplitudes and the same phase, generates a target canceling voltage vector, and further reverse-engineers the device capacity, virtual impedance, current limiting parameters, and transient voltage source reference values ​​of the grid-type reactive power compensation device, thereby reducing the combined voltage contribution vector after configuration and satisfying the transient overvoltage limit.

[0006] This invention is achieved through the following technical solution:

[0007] In a first aspect, the present invention provides a method for configuring a grid-type reactive power compensation device, the method comprising:

[0008] Obtain the system parameters of the new energy aggregation system; based on the system parameters, calculate the node impedance matrix when no grid-type reactive power compensation device is configured; based on the node impedance matrix, calculate the transient voltage contribution vector of each target node and form a multi-source transient voltage contribution vector.

[0009] Based on the magnitude and phase angle of the multi-source transient voltage contribution vector, identify a set of risk sources that form a superimposed risk in the same direction for transient overvoltages at the target node;

[0010] Based on the combined contribution vector of the target node transient voltage exceedance and the set of risk sources superimposed in the same direction, a target canceling voltage vector opposite to the direction of superposition is generated;

[0011] Based on the network-type reactive power compensation device, a programmable equivalent model of the device is constructed; and based on the programmable equivalent model of the device, the node impedance matrix and the target canceling voltage vector after configuring the network-type reactive power compensation device are calculated.

[0012] Based on the node impedance matrix and target phase-canceling voltage vector after configuring the grid-type reactive power compensation device, a configuration scheme is obtained based on the configuration optimization model; the configuration scheme includes the access location, device capacity and transient control parameters of the grid-type reactive power compensation device.

[0013] Furthermore, the system parameters include network topology, line parameters, transformer parameters, parallel branch parameters, bus parameters, new energy grid connection point parameters, DC transmission system AC bus parameters, target node set, risk source set and risk source access node, risk source transient reactive power risk quantity and pre-disturbance reference reactive power, voltage phasor of the node where the risk source is located, candidate network reactive power compensation device access node set, candidate device access line and step-up transformer parameters, capacity module, virtual impedance boundary, current limiting boundary, transient voltage source reference value boundary, transient overvoltage limit, and transient window set after fault clearance.

[0014] Furthermore, based on the system parameters, the node impedance matrix is ​​obtained when no grid-type reactive power compensation device is configured; based on the node impedance matrix, the transient voltage contribution vector of each target node is calculated and a multi-source transient voltage contribution vector is formed, including:

[0015] Based on the risk source set of system parameters, different types of transient overvoltage risk sources are converted into complex transient risk currents. Transient overvoltage risk sources include one or more of the following: continuous reactive power output sources after fault ride-through recovery of new energy power stations, residual capacitive reactive power sources of parallel capacitors or filters after fault clearance, transient reactive power surplus sources formed by the response lag of conventional dynamic reactive power compensation equipment, and reactive power mutation sources at the sending end caused by DC blocking or commutation failure.

[0016] Establish the node admittance matrix based on the system parameters; obtain the node impedance matrix when no grid-type reactive power compensation device is configured based on the node admittance matrix.

[0017] Based on the node impedance matrix and the complex transient risk current, calculate the transient voltage contribution vector of each risk source to each target node, arrange the transient voltage contribution vectors of all risk sources to all target nodes into a contribution matrix, and form a multi-source transient voltage contribution vector.

[0018] Furthermore, the formula for calculating the multi-source transient voltage contribution vector is as follows:

[0019] ;

[0020] ;

[0021] In the formula, Let be the transient voltage contribution matrix from the risk source to the target node under the h-th constraint scenario; n is the number of target nodes; m is the number of risk sources; The multi-source transient voltage contribution vector of the i-th target node under the h-th constraint scenario before configuring the grid-type reactive power compensation device; Let be the transient voltage contribution vector formed by the j-th risk source on the i-th target node; To configure the transfer impedance between the target node i and the node where the risk source is located in the front node impedance matrix; Let be the complex transient risk current of the j-th risk source.

[0022] Furthermore, identify a set of risk sources that form a superimposed risk in the same direction for transient overvoltages at the target node, including:

[0023] By comparing the phase angle between the transient voltage contribution vector and the multi-source transient voltage contribution vector of the target node, the set of risk sources superimposed in the same direction is determined;

[0024] When the magnitude of the transient voltage contribution vector is not less than the magnitude threshold and the cosine of the phase angle is not less than the same-direction threshold, the corresponding risk source is identified as a same-direction superimposed risk source.

[0025] Based on all identified risk sources that overlap in the same direction, a set of risk sources that overlap in the same direction is formed.

[0026] Furthermore, the target cancellation voltage vector is obtained by multiplying the composite contribution vector of the set of risk sources superimposed in the same direction by the cancellation coefficient and then inverting it;

[0027] The expression for the target destructive voltage vector is:

[0028] ;

[0029] ;

[0030] ;

[0031] In the formula, The composite contribution vector of the i-th target node under the h-th constraint scenario is formed by the set of risk sources superimposed in the same direction. The cancellation coefficient; This is the transient overvoltage limit for the i-th target node; Let be the target cancellation voltage vector of the i-th target node in the h-th constraint scenario. This target cancellation voltage vector is opposite in direction to the same direction superimposed synthetic contribution vector, and its magnitude is determined by the cancellation coefficient. The peak transient voltage of the i-th target node before configuring the grid-type reactive power compensation device; Let be the transient voltage contribution vector formed by the j-th risk source on the i-th target node; For small positive numbers, take 0.0001; Let be the set of overlapping risk sources in the same direction for the i-th target node in the h-th scenario.

[0032] Furthermore, the programmable equivalent model of the device is as follows: the grid-type reactive power compensation device is equivalent to a voltage source after impedance model with adjustable voltage source reference value, programmable virtual impedance and current limiting constraint, and the device current expression at the candidate access node and the node impedance matrix update expression after access are obtained.

[0033] Among them, grid-type reactive power compensation devices include grid-type SVG, grid-type STATCOM, and power electronic reactive power support devices with voltage source characteristics, bidirectional reactive power regulation capability, virtual impedance control, and current limiting capability.

[0034] Furthermore, based on the network-type reactive power compensation device, a programmable equivalent model of the device is constructed; and based on the programmable equivalent model, the node impedance matrix and target canceling voltage vector after configuring the network-type reactive power compensation device are calculated; based on the node impedance matrix and target canceling voltage vector after configuring the network-type reactive power compensation device, a configuration scheme is obtained based on the configuration optimization model, including:

[0035] Step A: Based on the network-type reactive power compensation device, construct a programmable equivalent model of the device; and calculate the node impedance matrix and target canceling voltage vector after configuring the network-type reactive power compensation device based on the programmable equivalent model of the device.

[0036] Step B involves using a weighted least squares approach to back-calculate the target current of each candidate access node from the target cancelling voltage vector. The target current of the device is then used to determine the lower limit of capacity, the number of capacity modules, the virtual impedance, the current limiting parameters, and the reference value of the transient voltage source. A configuration optimization model containing addressing variables, capacity module variables, and control parameter constraints is then established. Iterative optimization is performed based on the configuration optimization model to obtain the configuration scheme.

[0037] Step C: According to the configuration scheme, the configured candidate effective access impedances are incorporated into the node admittance matrix, the node impedance matrix is ​​recalculated, and the multi-source transient voltage contribution vector and the target node transient voltage peak value are calculated after configuring the grid-type reactive power compensation device.

[0038] When the transient overvoltage of any target node exceeds the limit, update the weight, candidate node set, capacity module or virtual impedance parameters and repeat steps A to C. When the transient overvoltage limit is met, output the connection location, device capacity and transient control parameters of the grid-type reactive power compensation device.

[0039] Furthermore, the iterative optimization process in step B is as follows:

[0040] B1, temporarily suspend the configuration of network-type reactive power compensation devices for all candidate nodes, and calculate the node impedance matrix, the set of risk sources superimposed in the same direction and the target canceling voltage vector before configuration;

[0041] B2, for each candidate node, reverse the target device current, determine the lower limit of capacity, the number of capacity modules, virtual impedance, current limiting parameters and voltage source reference value, and calculate the vector cancellation efficiency per unit capacity;

[0042] B3. Select the priority candidate pool according to the vector cancellation efficiency per unit capacity from large to small to form the initial configuration;

[0043] B4. In the candidate pool, use mixed integer optimization to solve the configuration optimization model, or use greedy iteration, add a capacity module or adjust a set of virtual impedance and / or current limiting parameters in each round, and select the configuration that maximizes the ratio of the decrease in the objective function of the configuration optimization model to the increase in capacity.

[0044] B5. Based on the trial configuration, update the node admittance matrix and node impedance matrix, and recalculate the multi-source transient voltage contribution vector, objective function, and target node transient voltage peak value.

[0045] B6. If the transient overvoltage constraint is met, stop; otherwise, increase the weight of the over-limit node or the cancellation coefficient, and return to step B2 to continue iterating until the preset capacity limit or iteration limit is reached.

[0046] Secondly, the present invention provides a grid-type reactive power compensation device configuration system, the system comprising:

[0047] The parameter acquisition unit is used to acquire the system parameters of the new energy aggregation system;

[0048] The multi-source transient voltage contribution vector calculation unit is used to obtain the node impedance matrix when no grid-type reactive power compensation device is configured based on system parameters; and to calculate the transient voltage contribution vector of each target node based on the node impedance matrix and form a multi-source transient voltage contribution vector.

[0049] The co-current superimposed risk source identification unit is used to identify a set of co-current superimposed risk sources that contribute to transient overvoltage at the target node based on the magnitude and phase angle of the multi-source transient voltage contribution vector.

[0050] The target cancellation voltage vector generation unit is used to generate a target cancellation voltage vector in the opposite direction of the same-direction superposition based on the target node transient voltage exceedance and the synthetic contribution vector of the same-direction superimposed risk source set.

[0051] The device programmable equivalent modeling unit is used to construct a programmable equivalent model of the device based on the network-type reactive power compensation device; and to calculate the node impedance matrix and target canceling voltage vector after configuring the network-type reactive power compensation device based on the programmable equivalent model of the device.

[0052] The configuration optimization unit is used to obtain a configuration scheme based on the node impedance matrix and target phase-canceling voltage vector after configuring the grid-type reactive power compensation device, and the configuration scheme includes the access location, device capacity and transient control parameters of the grid-type reactive power compensation device.

[0053] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0054] This invention discloses a method and system for configuring a grid-type reactive power compensation device. Instead of relying solely on short-circuit ratio, impedance ratio, or voltage over-limit amplitude as the configuration basis, this invention first calculates the complex transient voltage contribution vector (i.e., multi-source transient voltage contribution vector) formed at the target node after different risk sources are transferred by the network impedance. Then, it identifies a set of risk sources with large amplitudes and in the same phase, generates a target canceling voltage vector, and further deduces the device capacity, virtual impedance, current limiting parameters, and transient voltage source reference values ​​of the grid-type reactive power compensation device. This reduces the combined voltage contribution vector after configuration and satisfies the transient overvoltage limit. This invention can directly locate the in-phase superposition sources causing transient overvoltages and utilizes the adjustable amplitude and phase characteristics of the grid-type reactive power compensation device to achieve transient voltage contribution cancellation. This invention can be used for managing transient overvoltages after fault clearance in new energy bases, AC / DC transmission systems, weak AC transmission systems, and multi-site aggregation systems.

[0055] 1. This invention describes the overvoltage formation mechanism using a multi-source transient voltage contribution vector, which can simultaneously reflect the contribution amplitude and phase, and is no longer limited to scalar indicators such as short-circuit capacity, impedance ratio or voltage amplitude.

[0056] 2. This invention can identify the unidirectional superposition relationship of multiple risks such as new energy sources, filters, capacitors, and DC disturbances at the target node, and directly locate the set of dominant risk sources that cause the peak value of transient overvoltage to rise.

[0057] 3. This invention generates a target canceling voltage vector opposite to the direction of the superimposed risk, so that the configuration objective of the grid-type reactive power compensation device is changed from "improving system strength" to "constructing transient voltage cancellation conditions".

[0058] 4. This invention models the grid-type reactive power compensation device as an adjustable voltage source followed by a programmable impedance, and through an optimization model containing addressing variables, capacity module variables, and control parameter boundaries, simultaneously determines the connection location, capacity, virtual impedance, current limiting parameters, and transient voltage source reference values.

[0059] 5. This invention can quickly screen candidate nodes through analytical calculation and iterative optimization during the planning stage, and can be combined with time-domain simulation verification to improve the pertinence and economy of the transient overvoltage control scheme for new energy collection systems. Attached Figure Description

[0060] The accompanying drawings, which are included to provide a further understanding of embodiments of the invention and form part of this application, do not constitute a limitation thereof. In the drawings:

[0061] Figure 1 This is a flowchart of a method for configuring a grid-type reactive power compensation device according to the present invention;

[0062] Figure 2This is a schematic diagram illustrating the cancellation of the multi-source transient voltage contribution vectors in this invention;

[0063] Figure 3 This is a schematic diagram of the programmable equivalent model of the grid-type reactive power compensation device of the present invention;

[0064] Figure 4 This is a structural block diagram of a grid-type reactive power compensation device configuration system according to the present invention. Detailed Implementation

[0065] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0066] This invention requires a configuration method that can convert multi-source transient reactive power risks into complex voltage contribution vectors, identify risk sources that are superimposed in the same direction, and generate reverse transient contribution vectors using adjustable voltage sources and programmable virtual impedances of grid-type reactive power compensation devices, thereby transforming the traditional "enhanced system strength type" configuration into a "transient voltage contribution vector cancellation type" configuration.

[0067] The specific steps of this invention include: acquiring system parameters and transient windows; constructing complex transient risk currents; obtaining node impedance matrices; calculating multi-source transient voltage contribution vectors; identifying sets of risk sources superimposed in the same direction; generating target canceling voltage vectors; constructing a programmable equivalent model of the device; back-calculating configuration parameters and optimizing site selection and capacity; verifying transient voltages and outputting the solution.

[0068] This invention represents transient overvoltage risk as the result of synthesizing several complex voltage contribution vectors. For a target node, if the contribution vectors of multiple risk sources are close in direction, their synthesis will amplify the transient voltage peak in the same direction. This invention utilizes the adjustable voltage source reference value, programmable virtual impedance, and current limiting characteristics of a grid-type reactive power compensation device to form a voltage contribution vector (i.e., a target canceling voltage vector) at the candidate access node that is opposite to the direction of the superimposed risk in the same direction, thereby achieving the cancellation of transient voltage contributions.

[0069] Example 1

[0070] like Figure 1 As shown, Figure 1 This is a flowchart of a grid-type reactive power compensation device configuration method according to the present invention; the grid-type reactive power compensation device configuration method according to the present invention includes:

[0071] S1, Obtain the system parameters of the new energy aggregation system;

[0072] Specifically, the system parameters are the network parameters and transient overvoltage verification parameters of the new energy aggregation system under various constraint scenarios. These parameters include network topology, line parameters, transformer parameters, parallel branch parameters, aggregation bus parameters, new energy grid connection point parameters, DC transmission system AC bus parameters, target node set, risk source set and risk source access node, risk source transient reactive power risk quantity and pre-disturbance reference reactive power, voltage phasor of the node where the risk source is located, candidate network reactive power compensation device access node set (referred to as candidate node set), candidate device access line and step-up transformer parameters, capacity module, virtual impedance boundary, current limiting boundary, transient voltage source reference value boundary, transient overvoltage limit, and transient window set after fault clearance (referred to as constraint scenario set).

[0073] In one implementation, the target node set, risk source set, candidate node set, and constraint scenario set are defined as follows:

[0074]

[0075] In the formula, N is the target node set; S is the risk source set; K is the candidate network-type reactive power compensation device access node set, i.e., the candidate node set; H is the constraint scenario set; n, m, p, and q are the number of elements in their respective sets. Each risk source in the risk source set S corresponds to an access node. Transient reactive power risk Pre-disturbance baseline reactive power and the voltage phasor of the node Each candidate node in the candidate node set K corresponds to a capacity module, virtual impedance, current limiting boundary, and voltage source reference value boundary.

[0076] Each constraint scenario h can represent an operating mode, fault type, fault clearing time, DC disturbance depth, or transient time period. For example, 0–50 ms, 50–150 ms, and 150–300 ms after fault clearing can be set as different transient windows, and within each transient window, the reactive power of the risk source, the reference voltage of the target node, the virtual impedance boundary of the candidate device, the current limiting boundary, and the voltage source reference value boundary can be given respectively.

[0077] S2, based on the system parameters, obtain the node impedance matrix when no grid-type reactive power compensation device is configured; based on the node impedance matrix, calculate the transient voltage contribution vector of each target node and form a multi-source transient voltage contribution vector;

[0078] Specifically, step S2 includes:

[0079] S21, Constructing Complex Transient Risk Currents: Based on the risk source set of system parameters, different types of transient overvoltage risk sources are uniformly converted into complex transient risk currents; transient overvoltage risk sources include one or more of the following: continuous reactive power output sources after fault ride-through recovery of new energy power plants, residual capacitive reactive power sources of parallel capacitors or filters after fault clearance, transient reactive power surplus sources formed by the response lag of conventional dynamic reactive power compensation equipment, and reactive power mutation sources at the sending end caused by DC blocking or commutation failure;

[0080] It should be noted that short-term disturbances that do not fall into the above four categories and do not subsequently participate in contribution vector calculation and optimization constraints are not included in the risk source set S as risk sources.

[0081] In one implementation, the complex transient risk current of the risk source is determined according to the voltage phasor of the node where the risk source is located and the transient reactive power of the risk source. That is, the complex transient risk current of the j-th risk source under the h-th constraint scenario is determined as the reactive risk current divided by the conjugate of the voltage phasor of the node where the risk source is connected, and then multiplied by the negative imaginary unit.

[0082] The complex transient risk current of the risk source is:

[0083]

[0084] In the formula, Let be the complex transient risk current of the j-th risk source under the h-th constraint scenario; The imaginary unit; Let J represent the transient reactive power risk of the j-th risk source under the h-th constraint scenario. Let be the voltage phasor of the node where the risk source is located in the h-th constraint scenario; This is the mapping function from the risk source to the electrical node; the superscript * indicates complex conjugate.

[0085] For renewable energy power plants, the upper limit of continuous reactive power output after fault clearance, the average reactive power during the reactive power fall-off delay, or the time-sharing reactive power can be used. For filters and parallel capacitors, the residual capacitive reactive power still connected to the system after fault clearance can be used. For conventional dynamic reactive power compensation equipment, the reactive power surplus during the response lag or exit delay can be used. For DC disturbances, the equivalent value of the reactive power balance change of the sending-end AC bus after a sudden drop in DC power, blocking, or commutation failure can be used. The transient reactive power risk quantity of the risk source can be expressed as:

[0086]

[0087] In the formula, The reactive power output or equivalent reactive power of the j-th risk source under the h-th constraint scenario after fault clearance or disturbance; The baseline reactive power before the disturbance; max(· 0) indicates that the non-negative part is taken. For devices that absorb reactive power and reduce voltage in the agreed direction, their effect is not counted repeatedly as a risk source, but is treated as the cancellation contribution of grid-type reactive power compensation devices or cooperative devices in S5 to S6.

[0088] S22, Obtain the node impedance matrix: Establish the node admittance matrix based on the system parameters; Obtain the node impedance matrix without a grid-type reactive power compensation device based on the node admittance matrix.

[0089] For each constraint scenario h, a node admittance matrix is ​​established based on the AC network topology, line impedance, transformer impedance, parallel admittance, and operating mode, and the node impedance matrix is ​​obtained when no grid-type reactive power compensation device is configured.

[0090]

[0091] In the formula, Let be the node admittance matrix when no grid-type reactive power compensation device is configured in the h-th constraint scenario; This represents the corresponding node impedance matrix; the superscript 0 indicates the state before configuration; the superscript -1 indicates matrix inversion. If a reference node exists in the network, then... This is the node admittance matrix after eliminating the reference node.

[0092] The elements of the node impedance matrix represent the transfer impedance of a unit current injection at node r to the voltage change at target node i. When r = i, it is the self-impedance of the target node; when r ≠ i, it is the mutual impedance or transfer impedance between node r and target node i.

[0093] S23, Calculate the multi-source transient voltage contribution vector: Based on the node impedance matrix and the complex transient risk current, calculate the transient voltage contribution vector of each risk source to each target node, arrange the transient voltage contribution vectors of all risk sources to all target nodes into a contribution matrix, and form the multi-source transient voltage contribution vector.

[0094] In one implementation, the transient voltage contribution vector is defined as the product of the transfer impedance between the target node and the node where the risk source is connected in the node impedance matrix and the complex transient risk current of the risk source.

[0095] The transient voltage contribution vector is:

[0096]

[0097] In the formula, Let be the transient voltage contribution vector formed by the j-th risk source on the i-th target node; To configure the transfer impedance between the target node i and the node where the risk source is located in the front node impedance matrix; Let be the complex transient risk current of the j-th risk source under the h-th constraint scenario;

[0098] Arrange the contribution vectors of all risk sources to all target nodes into a contribution matrix, and calculate the multi-source composite contribution vector for each target node, i.e., the multi-source transient voltage contribution vector:

[0099]

[0100]

[0101] In the formula, Let be the transient voltage contribution matrix from the risk source to the target node under the h-th constraint scenario; n is the number of target nodes; m is the number of risk sources; This is the multi-source transient voltage contribution vector of the i-th target node under the h-th constraint scenario before configuring the grid-type reactive power compensation device.

[0102] The peak transient voltage of the i-th target node before configuration is:

[0103]

[0104] In the formula, Let be the equivalent system potential or reference operating voltage phasor of the i-th target node under the h-th constraint scenario; To configure the peak transient voltage.

[0105] Unlike simply calculating the voltage amplitude, the above technical solutions retain the complex direction of each contributing component in equations (5) to (8). Therefore, step S23 of the present invention can not only determine whether the overvoltage exceeds the limit, but also further determine whether the contributions of different risk sources are superimposed in the same direction.

[0106] S3, Identify the set of risk sources superimposed in the same direction: Based on the magnitude and phase angle of the multi-source transient voltage contribution vector, identify the set of risk sources that superimpose in the same direction on the transient overvoltage of the target node;

[0107] For target node i and constraint scenario h, calculate the phase angle between the j-th risk source contribution vector and the multi-source transient voltage contribution vector:

[0108]

[0109] In the formula, The phase angle between the contribution vector of the j-th risk source and the composite contribution vector of the i-th target node (i.e., the multi-source transient voltage contribution vector); Let be the transient voltage contribution vector formed by the j-th risk source on the i-th target node; The vector represents the multi-source transient voltage contribution of the i-th target node under the h-th constraint scenario before configuring the grid-type reactive power compensation device; ∠ represents the complex phase angle of the voltage.

[0110] When the magnitude of the transient voltage contribution vector of a certain risk source is large (greater than or equal to the contribution magnitude threshold), and its contribution vector direction is close to the direction of the multi-source transient voltage contribution vector, it is identified as a risk source with superimposed risk in the same direction:

[0111]

[0112] In the formula, Let be the set of overlapping risk sources in the same direction for the i-th target node under the h-th constraint scenario; The contribution amplitude threshold is used to eliminate risk sources with very little impact; The threshold value is for the same direction and can be set based on engineering experience or simulation verification results.

[0113] The above method determines the set of risk sources superimposed in the same direction by comparing the phase angle between the transient voltage contribution vector and the multi-source transient voltage contribution vector of the target node; when the amplitude of the transient voltage contribution vector is not less than the amplitude threshold and the cosine of the phase angle is not less than the same direction threshold, the corresponding risk source is identified as a risk source superimposed in the same direction.

[0114] S4, Generate target cancellation voltage vector: Based on the target node transient voltage exceedance and the composite contribution vector of the same-direction superimposed risk source set, generate a target cancellation voltage vector that is opposite to the same-direction superimposed direction;

[0115] The composite contribution vector of the set of risk sources superimposed in the same direction is:

[0116]

[0117] In the formula, The composite contribution vector of the i-th target node under the h-th constraint scenario is formed by the set of risk sources superimposed in the same direction. Let be the transient voltage contribution vector formed by the j-th risk source on the i-th target node; Let be the set of overlapping risk sources in the same direction for the i-th target node under the h-th constraint scenario;

[0118] Based on the combined contribution vector of the target node transient voltage exceedance and the set of risk sources superimposed in the same direction, the target cancelling voltage vector is generated:

[0119]

[0120] In the formula, The cancellation coefficient is determined based on the peak transient voltage, transient overvoltage limit, and magnitude of the composite contribution vector in the same direction before the target node is configured. This is the transient overvoltage limit for the i-th target node; Let be the target cancellation voltage vector of the i-th target node in the h-th constraint scenario. This target cancellation voltage vector is opposite in direction to the same direction superimposed composite contribution vector, and its magnitude is determined by the cancellation coefficient. When the voltage before configuration is not exceeded, it can be 0 or a smaller value can be taken according to the safety margin requirements. When the overvoltage exceeds the limit severely, the cancellation coefficient is increased.

[0121] The peak transient voltage of the i-th target node before configuring the grid-type reactive power compensation device; For small positive numbers, take 0.0001; Let be the set of overlapping risk sources in the same direction for the i-th target node in the h-th scenario.

[0122] like Figure 2 As shown, Figure 2 This is a schematic diagram of the cancellation of multi-source transient voltage contribution vectors in this invention. It shows that the contribution vectors of different risk sources are superimposed in the same direction to form the overvoltage contribution composite amount. The grid-type reactive power compensation device generates a reverse target cancellation vector to reduce the remaining composite amount. Figure 2 middle, , , These represent the transient voltage contribution vectors formed at the same target node after different transient risk sources are transmitted through network impedance; This represents the composite vector of the transient voltage of the target node before configuration, formed by superimposing the contribution vectors of multiple risk sources. This indicates that the target canceling voltage vector generated based on the set of risk sources in the same direction has the opposite direction to the composite contribution vector in the same direction.

[0123] The above technical solutions, through equations (11) and (12), transform the problem of "weakening the peak voltage of a certain node" into the problem of "generating a target canceling voltage vector that is opposite to the dominant superposition contribution", providing a clear vector target for the subsequent back-calculation of parameters of the grid-type reactive power compensation device.

[0124] S5, Construct a programmable equivalent model of the device: Based on the network-type reactive power compensation device, construct a programmable equivalent model of the device; and calculate the node impedance matrix and target canceling voltage vector after configuring the network-type reactive power compensation device based on the programmable equivalent model of the device.

[0125] Specifically, such as Figure 3 As shown, Figure 3 This is a schematic diagram of the programmable equivalent model of the grid-type reactive power compensation device of the present invention. The programmable equivalent model is as follows: the candidate grid-type reactive power compensation device is equivalent to a voltage source after impedance model with adjustable voltage source reference value, programmable virtual impedance and current limiting constraint, and the device current expression at the candidate access node and the node impedance matrix update expression after access are obtained.

[0126] Among them, grid-type reactive power compensation devices include grid-type SVG, grid-type STATCOM, and power electronic reactive power support devices with voltage source characteristics, bidirectional reactive power regulation capability, virtual impedance control, and current limiting capability.

[0127] The effective connection impedance of candidate grid-type reactive power compensation devices includes the connection line impedance, step-up transformer impedance, filter branch impedance, programmable virtual impedance, and current-limiting equivalent impedance. The programmable virtual impedance is set within a transient window according to a time period or constraint scenario. The effective connection impedance of candidate grid-type reactive power compensation devices is:

[0128]

[0129] In the formula, Let be the effective access impedance of the grid-type reactive power compensation device for candidate node k in the h-th constraint scenario. The impedance of the connected line; The impedance of the step-up transformer; This is the equivalent impedance of the filter branch or device side; This is a programmable virtual impedance for the h-th constraint scenario; This is the current-limiting equivalent impedance.

[0130] Virtual impedance and current-limiting equivalent impedance can be expressed as:

[0131]

[0132] In the formula, Let k be the virtual resistance of candidate node k under constraint scenario h; For virtual reactance; This is the current-limiting equivalent reactance. The virtual impedance can be set in segments according to the transient window. For example, a larger damping component is set in the early stage of fault clearing, a reactive power absorption-oriented reactance component is set in the middle stage, and the normal voltage support parameters are restored in the later stage.

[0133] The output current of the grid-type reactive power compensation device at candidate node k is expressed as:

[0134]

[0135] In the formula, Let be the complex current output by the grid-type reactive power compensation device at candidate node k under constrained scenario h; Reference value for transient voltage source of grid-type reactive power compensation device; Let k be the voltage phasor of candidate node k; This is the current limiting function; The permissible short-time current limit for grid-type reactive power compensation devices; This is a multiple of the short-time current. For device capacity; This is the rated voltage.

[0136] When calculating the network impedance after access, the adjustable voltage source is set to zero, and the candidate device behaves as an equivalent branch admittance from the access node to the reference node:

[0137]

[0138] In the formula, The admittance of the device access branch at candidate node k; Configure the node admittance matrix; Configure the node impedance matrix; Whether to configure the device's 0-1 variables for candidate node k; Let be the unit column vector corresponding to candidate node k; the superscript T indicates transpose.

[0139] S6. Based on the node impedance matrix and target phase-canceling voltage vector after configuring the grid-type reactive power compensation device, the configuration scheme is obtained based on the configuration optimization model. The configuration scheme includes the access location, device capacity and transient control parameters of the grid-type reactive power compensation device.

[0140] Specifically, step S6 includes:

[0141] S61, Establish a configuration optimization model and back-calculate configuration parameters to optimize location and capacity: Back-calculate the target current of the device for each candidate access node based on the target canceling voltage vector, and use the target current of the device to determine the lower limit of capacity, the number of capacity modules, virtual impedance, current limiting parameters and transient voltage source reference value; and establish a configuration optimization model containing location variables, capacity module variables and control parameter constraints, and perform iterative optimization based on the configuration optimization model to obtain the configuration scheme;

[0142] For a single candidate node k, in the h-th constraint scenario, to make the voltage contribution generated by the candidate node as close as possible to the target canceling voltage vector of multiple target nodes, the target current of the device can be back-calculated using a weighted least squares method:

[0143]

[0144] In the formula, Let k be the target device current of candidate node k under constrained scenario h; Let i be the weight of the target node i; The transfer impedance of node k to target node i after configuration or in trial configuration state; the superscript * indicates complex conjugate; The target phase-destruction voltage vector obtained from equation (12); It is a small positive number.

[0145] The required device capacity, number of capacity modules, and transient voltage source reference value for candidate node k are derived from the target device current. The required device capacity is used for capacity lower bound, capacity rounding, and current limiting verification. The transient voltage source reference value is used to determine the device control commands under programmable virtual impedance.

[0146]

[0147] In the formula, The candidate node k is required to meet the device target current capacity under the constraint scenario h; Candidate nodes The rated voltage or capacity calculation reference voltage for grid-type reactive power compensation devices; Let k be the target device current of candidate node k under constraint scenario h; Candidate nodes The capacity conversion factor of the device is used to take into account short-term overload capacity, current limiting margin, and capacity utilization factor, and ; Candidate nodes The actual configuration capacity of the grid-type reactive power compensation device; It is a discrete capacity module; This refers to the number of capacity modules; The reference value for the target transient voltage source of candidate node k under constraint scenario h; Candidate nodes In constrained scenarios The node voltage phasors below; Candidate nodes In constrained scenarios The effective connection impedance of the under-structure reactive power compensation device. Equation (18) serves as the source of three quantities in subsequent optimization: firstly, It is the lower bound of the candidate node capacity; secondly, Used to convert continuous capacity into discrete capacity modules; thirdly, and , The voltage source reference command for the grid-type reactive power compensation device within the transient window is determined jointly.

[0148] To evaluate the cancellation capability of candidate nodes per unit capacity, a candidate node per unit capacity vector cancellation efficiency is defined. This efficiency is used for candidate node sorting, initial solution construction, and iterative capacity expansion modules.

[0149]

[0150] In the formula, The unit capacity vector cancellation efficiency of candidate node k; This represents the objective function value when no grid-type reactive power compensation device is configured. The objective function value is the result of configuring only one capacity module at candidate node k and using the corresponding device target current and control parameters; For discrete capacity modules. Equation (19) is not used as a separate evaluation index, but is directly used for candidate node sorting, initial solution construction and greedy iterative selection in S61; The larger the value, the better the candidate node can counteract the risk of overlapping in the same direction under the same capacity increment, and it will be given priority to be included in the optimization candidate pool or to have its capacity module increased.

[0151] The site selection and capacity optimization is no longer merely described in principle, but rather an optimization model is established with 0-1 site selection variables and integer capacity variables. The optimized site selection and capacity includes a transient overvoltage penalty term. , Configuration of residual transient voltage contribution penalty item Target cancellation deviation penalty item and configuration capacity penalty items The goal is to minimize the weighted sum. Constraints include the target node's transient voltage peak not exceeding the limit, candidate access node location variables, discrete capacity modules, device capacity boundaries, virtual impedance boundaries, current limiting boundaries, and voltage source reference value boundaries. The node impedance matrix and configuration parameters are gradually updated through mixed integer optimization or greedy iteration.

[0152] Let the location variable, capacity module variable and capacity relationship be defined according to Equation (19-1); let the remaining contribution after configuration and the cancellation deviation be defined according to Equation (19-2); the optimization objective function is shown in Equation (19-4), the sub-items of each objective function are shown in Equations (19-5) to (19-8), and the constraints are shown in Equations (19-9) to (19-13).

[0153] Equation (19-1) defines the relationship between the location variable, the capacity module variable, and the discrete capacity:

[0154]

[0155] In the formula, Candidate nodes The addressing variable, when Time indicates in candidate node Configure a grid-type reactive power compensation device when This indicates that no device is configured at this node; Candidate nodes The number of capacity modules configured at the location, and must be a non-negative integer; Represents the set of non-negative integers; Candidate nodes The actual configuration capacity of the grid-type reactive power compensation device; Candidate nodes The capacity of a single discrete capacity module.

[0156] Equations (19-2) and (19-3) define the residual contribution and cancellation bias after configuration:

[0157]

[0158]

[0159] In the formula, After the candidate configuration scheme takes effect, the first The target node is in the constrained scenario. The remaining transient voltage contribution vector is used to characterize the remaining amount after the superposition of the risk source contribution and the reverse contribution of the grid-type reactive power compensation device. For the first The target node is in the constrained scenario. The target cancellation deviation vector is used to characterize the deviation between the actual cancellation contribution generated by the grid-type reactive power compensation device and the target cancellation voltage vector. A set of risk sources; The set of access nodes for candidate grid-type reactive power compensation devices; Number the risk source; Number the candidate access nodes; Number the target node; Number the constraint scene or transient window; As a source of risk Access node mapping function; After the candidate configuration schemes are implemented, the risk sources Node To the target node The transfer impedance; After the candidate configuration scheme is applied, the candidate nodes To the target node The transfer impedance; As a source of risk In constrained scenarios Complex transient risk currents; Candidate nodes In constrained scenarios, grid-type reactive power compensation devices The actual output current under these conditions; Candidate nodes Addressing variables; The target destructive voltage vector is generated based on the set of risk sources in the same direction; superscript This indicates the network state after the current candidate configuration scheme or the current iteration scheme takes effect.

[0160] Equation (19-2) is used to calculate the residual transient voltage contribution of the target node after configuration. The subsequent objective function minimizes... Or the square of its magnitude is used to reduce the risk of transient overvoltage; Equation (19-3) is used to calculate the deviation between the actual destructive contribution of the grid-type reactive power compensation device and the target destructive voltage vector, and the subsequent objective function is to minimize Or the square of its modulus, so that the device output is as close as possible to the desired reverse cancellation effect.

[0161] Equation (19-4) defines the objective function, and equations (19-5) to (19-8) define the individual terms of the objective function:

[0162]

[0163]

[0164]

[0165]

[0166]

[0167] In the formula, The comprehensive objective function of the location and capacity optimization model for grid-type reactive power compensation devices; This is a transient overvoltage limit penalty item, used to constrain the peak voltage of the target node after configuration from exceeding the transient overvoltage limit. This is a penalty term for the remaining transient voltage contribution after configuration, used to reduce the remaining vector after the superposition of multi-source risk contribution and device reverse contribution; This is the target cancellation deviation penalty term, used to make the actual cancellation contribution generated by the grid-type reactive power compensation device as close as possible to the target cancellation voltage vector; A capacity penalty term is used to constrain the total configuration capacity of grid-type reactive power compensation devices.

[0168] , , , These are the weighting coefficients for the transient overvoltage limit violation penalty, the residual transient voltage contribution penalty, the target phase cancellation deviation penalty, and the configuration capacity penalty, respectively, and all are non-negative numbers. They can be set according to the priority of transient overvoltage management, phase cancellation accuracy requirements, and configuration economic requirements. To constrain the scene or a set of transient windows; For the target node set; Number the constraint scene or transient window; Number the target node; For the first The target node is in the constrained scenario. The reference voltage phasor or equivalent system potential; After the candidate configuration scheme takes effect, the first The target node is in the constrained scenario. The residual transient voltage contribution vector under the condition; For the configured first The target node is in the constrained scenario. Voltage amplitude under; For the first Transient overvoltage limits for each target node; This indicates that only the portion exceeding the limit will be penalized; For the first The target node is in the constrained scenario. The target cancellation deviation vector below; The set of access nodes for candidate grid-type reactive power compensation devices; Number the candidate access nodes; Candidate nodes The actual configuration capacity of the grid-type reactive power compensation device.

[0169] Equation (19-5) prioritizes meeting the transient overvoltage limit by summing the squares of the voltage exceeding the limit after configuration; Equation (19-6) reduces the combined impact of risk sources after configuration by minimizing the residual transient voltage contribution vector; Equation (19-7) minimizes the target cancellation deviation to make the reverse contribution of the actual output of the device as close as possible to the target cancellation voltage vector; Equation (19-8) minimizes the total configuration capacity to make the site selection and capacity determination results take into account economic efficiency.

[0170] in, Pay attention to the final residual overvoltage risk after configuration. We focus on the approximation between the device contribution and the target cancellation vector, and constrain the optimization process from the perspectives of result constraints and control objectives, respectively.

[0171] Equations (19-9) to (19-13) provide the constraints for site selection, volume determination, and control parameters:

[0172]

[0173]

[0174]

[0175]

[0176]

[0177] In the formula, For the first The target node is in the constrained scenario. The reference voltage phasor or equivalent system potential; After the candidate configuration scheme takes effect, the first The target node is in the constrained scenario. The residual transient voltage contribution vector under the condition; For the first Transient overvoltage limits for each target node; For the target node set; To constrain the scene or a set of transient windows; Number the target node; Number the constraint scene or transient window.

[0178] Candidate nodes The addressing variable, when Time indicates in candidate node Configure a grid-type reactive power compensation device when This indicates that no device is configured at this node; Candidate nodes The actual configuration capacity of the grid-type reactive power compensation device; and Candidate nodes The minimum and maximum capacity that can be configured; The set of access nodes for candidate grid-type reactive power compensation devices; The maximum number of nodes allowed for configuring a grid-type reactive power compensation device.

[0179] Candidate nodes In constrained scenarios, grid-type reactive power compensation devices The actual output current under these conditions; Candidate nodes The permissible short-time current limit for grid-type reactive power compensation devices; Candidate nodes The permissible short-time overload multiple or short-time current multiple of the device; Candidate nodes The rated voltage or capacity calculation reference voltage for grid-type reactive power compensation devices.

[0180] Candidate nodes In constrained scenarios, grid-type reactive power compensation devices The virtual resistor is set below; and These are the lower and upper limits of the virtual resistance, respectively; Candidate nodes In constrained scenarios, grid-type reactive power compensation devices The virtual reactance is set below; and These are the lower and upper limits of the virtual reactance, respectively.

[0181] Candidate nodes In constrained scenarios, grid-type reactive power compensation devices The transient voltage source reference value is as follows; Candidate nodes In constrained scenarios The node voltage phasors below; Candidate nodes In constrained scenarios Effective connection impedance of the under-structure reactive power compensation device; Candidate nodes The allowable range of reference values ​​for the transient voltage source can be determined by the upper limit of voltage amplitude, the lower limit of voltage amplitude, phase angle constraint, modulation margin, and control stability requirements.

[0182] Equation (19-9) is used to ensure that the transient voltage amplitude of all target nodes under all constrained scenarios after configuration does not exceed the transient overvoltage limit; Equation (19-10) is used to constrain the configuration capacity of candidate nodes and the maximum number of configured nodes, and to ensure that when When the node capacity is zero; Equation (19-11) is used to constrain the output current of the grid-type reactive power compensation device from not exceeding the short-time current limit, and the short-time current limit is not exceeding the allowable value determined by the device capacity and short-time overload capacity; Equation (19-12) is used to constrain the adjustable range of the virtual impedance of the grid-type reactive power compensation device; Equation (19-13) is used to constrain the transient voltage source reference value to be jointly determined by the node voltage, effective access impedance and device output current, and to be within the allowable control range.

[0183] In Equation (19-4), the first term is used to suppress transient voltage over-limit, the second term is used to reduce the remaining synthetic contribution after configuration, the third term is used to constrain the device contribution to approach the target canceling voltage vector, and the fourth term is used to constrain configuration economy; Equations (19-9) to (19-13) respectively constrain transient voltage peak value, capacity boundary, discrete module, number of candidate nodes, current limit, virtual impedance and voltage source reference value range.

[0184] The iterative optimization process is as follows:

[0185] The first step is to temporarily suspend the configuration of grid-type reactive power compensation devices at all candidate nodes, and calculate the node impedance matrix, the set of risk sources superimposed in the same direction, and the target canceling voltage vector before configuration according to S2 to S4.

[0186] The second step is to use Equation (17) to back-calculate the target device current for each candidate node, use Equation (18) to determine the lower limit of capacity, the number of capacity modules and the reference value of voltage source, and use Equation (19) to calculate the unit capacity vector cancellation efficiency.

[0187] The third step is to select a priority candidate pool based on the vector cancellation efficiency per unit capacity from largest to smallest to form the initial configuration;

[0188] The fourth step is to use mixed integer optimization to solve the configuration optimization model in the candidate pool, or to use greedy iteration, adding a capacity module or adjusting a set of virtual impedance and / or current limiting parameters in each round, and selecting the configuration that maximizes the ratio of the decrease in the objective function of the configuration optimization model to the capacity increment.

[0189] Fifth, based on the trial configuration, update the node admittance matrix and node impedance matrix, and recalculate the multi-source transient voltage contribution vector, objective function, and target node transient voltage peak value;

[0190] Step 6: If the transient overvoltage constraint is met, stop; otherwise, increase the weight of the over-limit node or the cancellation coefficient, return to step 2 and continue iterating until the preset capacity limit or iteration limit is reached.

[0191] Therefore, the capacity and voltage source reference values ​​of equation (18) enter the capacity boundary, capacity module rounding, current limiting verification and control parameter generation stages; the unit capacity vector cancellation efficiency of equation (19) enters the candidate node sorting, initial solution generation and greedy iterative selection stages.

[0192] S62, Iteratively verify transient voltage and output scheme: According to the configuration scheme, the configured candidate effective access impedance is incorporated into the node admittance matrix, the node impedance matrix is ​​recalculated, and the multi-source transient voltage contribution vector and the target node transient voltage peak value are calculated after configuring the grid-type reactive power compensation device; In engineering implementation, the configuration scheme obtained by analytical calculation can also be imported into the electromagnetic transient or electromechanical transient simulation model for verification.

[0193] The configured target node synthesized contribution vector (i.e., multi-source transient voltage contribution vector) and transient voltage peak value can be expressed as:

[0194]

[0195]

[0196] In the formula, The target node contribution vector (i.e., multi-source transient voltage contribution vector) is the target node synthesis contribution vector of the i-th target node under the constraint scenario h after configuration. Risk sources in the configured network state Node To the target node The transfer impedance, Let be the complex transient risk current of the j-th risk source under the h-th constraint scenario; Candidate nodes The addressing variable, when Time indicates in candidate node Configure a grid-type reactive power compensation device when When it is not configured, Candidate nodes in the configured network state To the target node The transfer impedance, Candidate nodes In constrained scenarios, grid-type reactive power compensation devices The actual output current; S is the set of risk sources; K is the set of candidate network-type reactive power compensation device access nodes, i.e., the candidate node set;

[0197] The peak transient voltage of the i-th target node under constraint scenario h after configuration; For the first The target node is in the constrained scenario. The reference voltage phasor or equivalent system potential.

[0198] If the following conditions are met, then output the configuration scheme:

[0199]

[0200] In the formula, After configuring the grid-type reactive power compensation device, the first The target node is in the constrained scenario. The peak transient voltage; Let be the transient overvoltage limit for the i-th target node. If equation (21) is not satisfied, then update the weights according to the degree of exceeding the limit for the target node i and the over-limit scenario h. And the cancellation coefficient; recalculate the target cancellation voltage vector, the target device current of Equation (17), the number of capacity modules and the transient voltage source reference value of Equation (18), and the unit capacity vector cancellation efficiency of Equation (19); then add capacity modules, adjust the virtual impedance boundary or current limiting boundary, expand the candidate node set, and repeat S5 to S6.

[0201] The final output configuration scheme includes at least the following: the access node of the grid-type reactive power compensation device, the configuration capacity, the number of capacity modules, the access line and step-up transformer parameters, the virtual impedance under each transient window, the short-time current multiple, the current limit value, the transient voltage source reference value, the risk source superposition set corresponding to the target node, the device target current derived from Equation (17), the capacity lower limit and voltage source reference value obtained from Equation (18), the unit capacity vector cancellation efficiency obtained from Equation (19), and the transient voltage peak value before and after configuration.

[0202] In specific implementation, taking the new energy aggregation system as an example, the target nodes include multiple new energy grid connection points, aggregation buses, and converter station AC buses; risk sources include continuous reactive power output sources after the recovery of new energy station faults, residual capacitive reactive power sources of parallel capacitors or filters, transient reactive power surplus sources formed by the response lag of conventional dynamic reactive power compensation equipment, and reactive power mutation sources at the sending end after DC blocking; candidate grid-type reactive power compensation device access nodes include the high-voltage side buses of each new energy booster station, aggregation station buses, and converter station AC buses.

[0203] First, obtain the parameters of the line, transformer, and parallel branches according to S1, and define three transient windows after fault clearance: 0–50 ms, 50–150 ms, and 150–300 ms. Then, convert each risk source into a complex transient risk current according to S21. Next, establish the node impedance matrix under each transient window according to S22, and calculate the transient voltage contribution vector of each risk source to each target node according to S23.

[0204] If calculations reveal that the contribution vector directions of multiple reactive power risk sources from new energy power plants and the residual reactive power sources from filters at a certain busbar are close, and the amplification factor of the vectors in the same direction is high, then according to S3, they are identified as a set of risk sources superimposed in the same direction. Subsequently, according to S4, a target canceling voltage vector with the opposite direction to the combined contribution vector of this set is generated.

[0205] In S5, the candidate grid-type reactive power compensation device is modeled as an adjustable voltage source followed by an impedance. A higher virtual damping is set in the early stage of fault clearing, a virtual impedance guided by reactive power absorption and phase cancellation is set in the middle stage, and the voltage support parameters are restored in the later stage. In S61, the target current of the candidate node is first deduced using equation (17), then the number of capacity modules and the reference value of the voltage source are obtained using equation (18), and the unit capacity vector cancellation efficiency is calculated using equation (19); subsequently, according to... A priority candidate pool is formed, and capacity modules are gradually increased and node impedance matrices are updated using mixed integer optimization or greedy iteration. Finally, the peak transient voltage after configuration is recalculated according to S62. If it still exceeds the limit, the weight of the node exceeding the limit is increased and S5 to S6 are repeated until the limit is met, and then the configuration scheme is output.

[0206] Example 2

[0207] like Figure 4 As shown, Figure 4 This is a structural block diagram of a grid-type reactive power compensation device configuration system according to the present invention. The difference between this embodiment and Embodiment 1 is that this embodiment further provides a grid-type reactive power compensation device configuration system, which corresponds one-to-one with the grid-type reactive power compensation device configuration method of Embodiment 1; the system includes:

[0208] The parameter acquisition unit is used to acquire the system parameters of the new energy aggregation system;

[0209] The multi-source transient voltage contribution vector calculation unit is used to obtain the node impedance matrix when no grid-type reactive power compensation device is configured based on system parameters; and to calculate the transient voltage contribution vector of each target node based on the node impedance matrix and form a multi-source transient voltage contribution vector.

[0210] The co-current superimposed risk source identification unit is used to identify a set of co-current superimposed risk sources that contribute to transient overvoltage at the target node based on the magnitude and phase angle of the multi-source transient voltage contribution vector.

[0211] The target cancellation voltage vector generation unit is used to generate a target cancellation voltage vector in the opposite direction of the same-direction superposition based on the target node transient voltage exceedance and the synthetic contribution vector of the same-direction superimposed risk source set.

[0212] The device programmable equivalent modeling unit is used to construct a programmable equivalent model of the device based on the network-type reactive power compensation device; and to calculate the node impedance matrix and target canceling voltage vector after configuring the network-type reactive power compensation device based on the programmable equivalent model of the device.

[0213] The configuration optimization unit is used to obtain a configuration scheme based on the node impedance matrix and target phase-canceling voltage vector after configuring the grid-type reactive power compensation device, and the configuration scheme includes the access location, device capacity and transient control parameters of the grid-type reactive power compensation device.

[0214] The execution process of each unit can be carried out according to the configuration method of a grid-type reactive power compensation device in Embodiment 1, and will not be described in detail in this embodiment.

[0215] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0216] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations 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, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0217] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0218] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0219] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for configuring a grid-type reactive power compensation device, characterized in that, The method includes: Obtain the system parameters of the new energy aggregation system; based on the system parameters, calculate the node impedance matrix when no grid-type reactive power compensation device is configured; based on the node impedance matrix, calculate the transient voltage contribution vector of each target node and form a multi-source transient voltage contribution vector. Based on the magnitude and phase angle of the multi-source transient voltage contribution vector, identify a set of risk sources that form a superimposed risk in the same direction for transient overvoltage at the target node; Based on the target node transient voltage exceedance and the combined contribution vector of the same-direction superimposed risk source set, a target cancellation voltage vector opposite to the same-direction superimposed direction is generated; Based on the network-type reactive power compensation device, a programmable equivalent model of the device is constructed; and based on the programmable equivalent model of the device, the node impedance matrix and the target canceling voltage vector after configuring the network-type reactive power compensation device are calculated. Based on the node impedance matrix and target phase-canceling voltage vector after configuring the grid-type reactive power compensation device, a configuration scheme is obtained based on the configuration optimization model; the configuration scheme includes the access location, device capacity and transient control parameters of the grid-type reactive power compensation device.

2. The configuration method of a grid-type reactive power compensation device according to claim 1, characterized in that, The system parameters include network topology, line parameters, transformer parameters, parallel branch parameters, bus parameters, new energy grid connection point parameters, DC transmission system AC bus parameters, target node set, risk source set and risk source access node, risk source transient reactive power risk quantity and pre-disturbance reference reactive power, voltage phasor of the node where the risk source is located, candidate network reactive power compensation device access node set, candidate device access line and step-up transformer parameters, capacity module, virtual impedance boundary, current limiting boundary, transient voltage source reference value boundary, transient overvoltage limit, and transient window set after fault clearance.

3. The configuration method of a grid-type reactive power compensation device according to claim 1, characterized in that, Based on the system parameters, obtain the node impedance matrix when no grid-type reactive power compensation device is configured; Based on the node impedance matrix, the transient voltage contribution vector of each target node is calculated, and a multi-source transient voltage contribution vector is formed, including: Based on the risk source set of the system parameters, different types of transient overvoltage risk sources are converted into complex transient risk currents; the transient overvoltage risk sources include one or more of the following: continuous reactive power output sources after fault ride-through recovery of new energy power stations, residual capacitive reactive power sources of parallel capacitors or filters after fault clearance, transient reactive power surplus sources formed by the response lag of conventional dynamic reactive power compensation equipment, and reactive power mutation sources at the sending end caused by DC blocking or commutation failure. Establish the node admittance matrix based on the system parameters; obtain the node impedance matrix when no grid-type reactive power compensation device is configured based on the node admittance matrix. Based on the node impedance matrix and the complex transient risk current, calculate the transient voltage contribution vector of each risk source to each target node, arrange the transient voltage contribution vectors of all risk sources to all target nodes into a contribution matrix, and form a multi-source transient voltage contribution vector.

4. The configuration method of a grid-type reactive power compensation device according to claim 3, characterized in that, The formula for calculating the multi-source transient voltage contribution vector is as follows: ； ； In the formula, Let be the transient voltage contribution matrix from the risk source to the target node under the h-th constraint scenario; n is the number of target nodes; m is the number of risk sources; The multi-source transient voltage contribution vector of the i-th target node under the h-th constraint scenario before configuring the grid-type reactive power compensation device; Let be the transient voltage contribution vector formed by the j-th risk source on the i-th target node; To configure the transfer impedance between the target node i and the node where the risk source is located in the front node impedance matrix; Let be the complex transient risk current of the j-th risk source; A set of risk sources; This is the mapping function from the risk source to the electrical node.

5. The configuration method of a grid-type reactive power compensation device according to claim 1, characterized in that, Identify a set of risk sources that form a synergistic superposition of transient overvoltages at the target node, including: By comparing the phase angle between the transient voltage contribution vector and the multi-source transient voltage contribution vector of the target node, the set of risk sources superimposed in the same direction is determined; When the magnitude of the transient voltage contribution vector is not less than the magnitude threshold and the cosine of the phase angle is not less than the same-direction threshold, the corresponding risk source is identified as a same-direction superimposed risk source. Based on all identified risk sources that overlap in the same direction, a set of risk sources that overlap in the same direction is formed.

6. The configuration method of a grid-type reactive power compensation device according to claim 1, characterized in that, The target cancellation voltage vector is obtained by multiplying the composite contribution vector of the set of risk sources superimposed in the same direction by the cancellation coefficient and then inverting it; The expression for the target destructive voltage vector is: ； ； ； In the formula, The composite contribution vector of the i-th target node under the h-th constraint scenario is formed by the set of risk sources superimposed in the same direction. The cancellation coefficient; This is the transient overvoltage limit for the i-th target node; Let be the target cancellation voltage vector of the i-th target node in the h-th constraint scenario. This target cancellation voltage vector is opposite in direction to the same direction superimposed synthetic contribution vector, and its magnitude is determined by the cancellation coefficient. The peak transient voltage of the i-th target node before configuring the grid-type reactive power compensation device; Let be the transient voltage contribution vector formed by the j-th risk source on the i-th target node; For small positive numbers, take 0.0001; Let be the set of overlapping risk sources in the same direction for the i-th target node in the h-th scenario.

7. The configuration method of a grid-type reactive power compensation device according to claim 1, characterized in that, The programmable equivalent model of the device is as follows: the grid-type reactive power compensation device is equivalent to a voltage source after impedance model with adjustable voltage source reference value, programmable virtual impedance and current limiting constraint, and the device current expression at the candidate access node and the node impedance matrix update expression after access are obtained. The grid-type reactive power compensation device includes a grid-type SVG, a grid-type STATCOM, and a power electronic reactive power support device with voltage source characteristics, bidirectional reactive power regulation capability, virtual impedance control, and current limiting capability.

8. The configuration method of a grid-type reactive power compensation device according to claim 1, characterized in that, Based on the network-type reactive power compensation device, a programmable equivalent model of the device is constructed; and based on the programmable equivalent model of the device, the node impedance matrix and the target canceling voltage vector after configuring the network-type reactive power compensation device are calculated. Based on the node impedance matrix and target canceling voltage vector after configuring the network-type reactive power compensation device, a configuration scheme is obtained based on the configuration optimization model, including: Step A: Construct a programmable equivalent model of the network-type reactive power compensation device; and calculate the node impedance matrix and target canceling voltage vector after configuring the network-type reactive power compensation device based on the programmable equivalent model of the device. Step B involves using a weighted least squares approach to back-calculate the target current of the device for each candidate access node from the target cancelling voltage vector. The target current of the device is then used to determine the lower limit of capacity, the number of capacity modules, the virtual impedance, the current limiting parameters, and the reference value of the transient voltage source. A configuration optimization model containing addressing variables, capacity module variables, and control parameter constraints is then established. Iterative optimization is performed based on the configuration optimization model to obtain the configuration scheme. Step C: According to the configuration scheme, the configured candidate effective access impedances are incorporated into the node admittance matrix, the node impedance matrix is ​​recalculated, and the multi-source transient voltage contribution vector and the target node transient voltage peak value are calculated after configuring the grid-type reactive power compensation device. When the transient overvoltage of any target node exceeds the limit, update the weight, candidate node set, capacity module or virtual impedance parameters and repeat steps A to C. When the transient overvoltage limit is met, output the connection location, device capacity and transient control parameters of the grid-type reactive power compensation device.

9. A method for configuring a grid-type reactive power compensation device according to claim 8, characterized in that, The iterative optimization process in step B is as follows: B1, temporarily suspend the configuration of network-type reactive power compensation devices for all candidate nodes, and calculate the node impedance matrix, the set of risk sources superimposed in the same direction and the target canceling voltage vector before configuration; B2, for each candidate node, reverse the target device current, determine the lower limit of capacity, the number of capacity modules, virtual impedance, current limiting parameters and voltage source reference value, and calculate the vector cancellation efficiency per unit capacity; B3. Select a priority candidate pool from largest to smallest according to the unit capacity vector cancellation efficiency to form the initial configuration; B4. In the candidate pool, the configuration optimization model is solved by mixed integer optimization, or by greedy iteration, adding a capacity module or adjusting a set of virtual impedance and / or current limiting parameters in each round, and selecting the configuration that maximizes the ratio of the decrease in the objective function of the configuration optimization model to the capacity increment. B5. Based on the trial configuration, update the node admittance matrix and node impedance matrix, and recalculate the multi-source transient voltage contribution vector, objective function, and target node transient voltage peak value. B6. If the transient overvoltage constraint is met, stop; otherwise, increase the weight of the over-limit node or the cancellation coefficient, and return to step B2 to continue iterating until the preset capacity limit or iteration limit is reached.

10. A grid-type reactive power compensation device configuration system, characterized in that, The system includes: The parameter acquisition unit is used to acquire the system parameters of the new energy aggregation system; The multi-source transient voltage contribution vector calculation unit is used to obtain the node impedance matrix when no grid-type reactive power compensation device is configured based on system parameters; and to calculate the transient voltage contribution vector of each target node based on the node impedance matrix and form a multi-source transient voltage contribution vector. The co-current superimposed risk source identification unit is used to identify a set of co-current superimposed risk sources that contribute to transient overvoltage at the target node based on the magnitude and phase angle of the multi-source transient voltage contribution vector. The target cancellation voltage vector generation unit is used to generate a target cancellation voltage vector opposite to the direction of the same-direction superposition based on the target node transient voltage exceedance and the synthetic contribution vector of the same-direction superimposed risk source set. The device programmable equivalent modeling unit is used to construct a programmable equivalent model of the device based on the network-type reactive power compensation device; and to calculate the node impedance matrix and target cancellation voltage vector after configuring the network-type reactive power compensation device based on the programmable equivalent model of the device. The configuration optimization unit is used to obtain a configuration scheme based on the node impedance matrix and target canceling voltage vector after configuring the grid-type reactive power compensation device, and the configuration scheme includes the access location, device capacity and transient control parameters of the grid-type reactive power compensation device.

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