A method and device for configuring SVG converter valve parameters

Abstract

The present invention discloses a method and device for configuring parameters of an SVG converter valve, the method comprising: determining the capacity and rated working voltage of the converter valve according to the basic functional requirements of the SVG; determining the type and rated working voltage of the submodule according to the capacity and rated working voltage of the converter valve, and determining the number of submodules in combination with third harmonic injection and harmonic suppression; determining the submodule capacitance value and bridge arm reactor parameters according to the volatility of the submodule capacitor voltage and the harmonic suppression requirements in a steady state; optimizing the number of submodules, capacitance value and bridge arm reactor parameters according to the overvoltage and overcurrent characteristics of the SVG; determining the arrester configuration according to the overvoltage characteristics of the SVG after parameter optimization, and obtaining the converter valve parameter configuration of the SVG. The present invention is applicable to the design of an ultra-high voltage SLCC direct current transmission system, and can effectively improve the efficiency and standardization of system design.

Description

Technical Field

[0001] The present invention relates to the technical field of direct current transmission, and in particular to a method and device for configuring parameters of an SVG converter valve. Background Art

[0002] The SVG (Static Var Generator) is configured on the transformer valve side. The converter composed of the SVG and LCC (Line Commutated Converter) is called SLCC (Self-Commutated Converter), which can compensate for the reactive power consumption and harmonic current during the operation of LCC. The system does not need to be equipped with additional AC filters / parallel capacitors, and can effectively solve problems such as AC low voltage ride-through and receiving end commutation failure. Similar to flexible DC transmission, the converter valve parameters are the core factors that determine the performance of SVG, but the topological structure and main functions of SVG are quite different from those of flexible DC transmission systems. The converter valve parameter design method in the existing flexible DC transmission system is difficult to correspond to the UHV SLCC system.

[0003] Therefore, there is an urgent need for a SVG converter valve parameter configuration method for a UHV SLCC DC transmission system. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a method and device for configuring SVG converter valve parameters, clarifies the design steps of SVG converter valve parameters in the UHV SLCC DC transmission system, and improves the system design efficiency and standardization.

[0005] An embodiment of the present invention provides a method for configuring parameters of an SVG converter valve, which is applied to an ultra-high voltage SLCC direct current transmission system. The method includes:

[0006] According to the basic functional requirements of the static VAR generator SVG, determine the capacity and rated operating voltage of the converter valve;

[0007] Determine the type and rated operating voltage of the submodule according to the capacity and rated operating voltage of the converter valve, and determine the number of submodules in combination with the third harmonic injection capability and harmonic suppression capability of the SVG;

[0008] Determine the submodule capacitance value and bridge arm reactor parameters according to the fluctuation of the submodule capacitor voltage in a steady state and the harmonic suppression requirement of the SVG;

[0009] According to the overvoltage and overcurrent characteristics of the SVG, the number of submodules, the capacitance value of the submodules and the parameters of the bridge arm reactor are optimized to obtain the SVG after parameter optimization;

[0010] According to the overvoltage characteristics of the SVG after parameter optimization, the arrester configuration position and parameters are determined to obtain the converter valve parameter configuration of the SVG.

[0011] As an improvement of the above solution, the basic functional requirements of the SVG include:

[0012] After a fault occurs in the receiving grid, the AC bus voltage of the phase-commutating converter is supported for a short period of time;

[0013] While offsetting the reactive power consumption of the converter transformer and the phase-commutation converter, it also meets the reactive power demand of the AC power grid;

[0014] The harmonic components of the AC power grid are controlled not to flow into the phase-commutating converter; the harmonic components are obtained by investigating the harmonic components of the AC power grid based on the topological structure of the UHV SLCC DC power transmission system.

[0015] As an improvement of the above solution, the type and rated operating voltage of the submodule are determined according to the capacity and rated operating voltage of the converter valve, and the number of submodules is determined in combination with the third harmonic injection capability and harmonic suppression capability of the SVG, including:

[0016] The rated current of the bridge arm is calculated according to the capacity and rated working voltage of the converter valve;

[0017] Determining the specifications of the insulated gate bipolar transistor according to the rated current of the bridge arm;

[0018] Determining the type and rated operating voltage of the submodule according to the rated current of the bridge arm and the specifications of the insulated gate bipolar transistor;

[0019] According to the rated operating voltage of the submodule, the number of submodules of the bridge arm under the rated state is calculated;

[0020] Based on the influence of the third harmonic injection capability and harmonic suppression capability of the SVG on the number of sub-modules, the number of sub-modules is corrected to obtain a corrected number of sub-modules.

[0021] As an improvement of the above solution, the submodule capacitance value and the bridge arm reactor parameters are determined according to the fluctuation of the submodule capacitor voltage in a steady state and the harmonic suppression requirement of the SVG, including:

[0022] According to the fluctuation rate limit of the submodule capacitor voltage in steady state, the required submodule capacitance value in steady state is calculated;

[0023] According to the valve-controlled overcurrent protection setting value, the device overcurrent tolerance and the protection action delay, the maximum bridge arm current rise rate allowed by the SVG is calculated;

[0024] The bridge arm reactor parameters are obtained according to the maximum value of the bridge arm current rising rate and the maximum voltage drop of the SVG bridge arm in a steady state and a fault condition.

[0025] As an improvement of the above solution, the number of submodules, the capacitance value of the submodules and the parameters of the bridge arm reactor are optimized according to the overvoltage and overcurrent characteristics of the SVG, including:

[0026] Simulate and analyze the SVG converter valve to obtain the overvoltage and overcurrent characteristics of the SVG;

[0027] Based on the overvoltage characteristics, determining an overvoltage suppression measure, and updating the number of submodules and the capacitance value of the submodules according to the overvoltage suppression measure;

[0028] Based on the overcurrent characteristics and the overvoltage suppression measures, the bridge arm reactor parameters are updated.

[0029] As an improvement of the above solution, the method of determining the configuration position and parameters of the arrester according to the overvoltage characteristics of the SVG after the parameter optimization includes:

[0030] Performing simulation analysis on the SVG after parameter optimization to obtain an overvoltage condition of the SVG after parameter optimization under an extreme overvoltage condition;

[0031] According to the overvoltage situation and the requirements of the converter valve equipment, the configuration location and parameters of the lightning arrester are determined.

[0032] The embodiment of the present invention further provides a SVG converter valve parameter configuration device, which is applied to an ultra-high voltage SLCC direct current transmission system, and the device includes:

[0033] The converter valve capacity module is used to determine the capacity and rated working voltage of the converter valve according to the basic functional requirements of the static VAR generator SVG;

[0034] A submodule selection module, used to determine the type and rated operating voltage of the submodule according to the capacity and rated operating voltage of the converter valve, and determine the number of submodules in combination with the third harmonic injection capability and harmonic suppression capability of the SVG;

[0035] A submodule capacitor module, used to determine the submodule capacitor value and bridge arm reactor parameters according to the volatility of the submodule capacitor voltage in a steady state and the harmonic suppression requirements of the SVG;

[0036] A parameter optimization module, used to optimize the number of submodules, the capacitance value of the submodules and the bridge arm reactor parameters according to the overvoltage and overcurrent characteristics of the SVG, so as to obtain the SVG after parameter optimization;

[0037] The arrester configuration module is used to determine the arrester configuration position and parameters according to the overvoltage characteristics of the SVG after the parameter optimization, and obtain the converter valve parameter configuration of the SVG.

[0038] Furthermore, the submodule selection module is specifically used for:

[0039] The rated current of the bridge arm is calculated according to the capacity and rated working voltage of the converter valve;

[0040] Determining the specifications of the insulated gate bipolar transistor according to the rated current of the bridge arm;

[0041] Determining the type and rated operating voltage of the submodule according to the rated current of the bridge arm and the specifications of the insulated gate bipolar transistor;

[0042] According to the rated operating voltage of the submodule, the number of submodules of the bridge arm under the rated state is calculated;

[0043] Based on the influence of the third harmonic injection capability and harmonic suppression capability of the SVG on the number of sub-modules, the number of sub-modules is corrected to obtain a corrected number of sub-modules.

[0044] Furthermore, the submodule capacitor module is specifically used for:

[0045] According to the fluctuation rate limit of the submodule capacitor voltage in steady state, the required submodule capacitance value in steady state is calculated;

[0046] According to the valve-controlled overcurrent protection setting value, the device overcurrent tolerance and the protection action delay, the maximum bridge arm current rise rate allowed by the SVG is calculated;

[0047] The bridge arm reactor parameters are obtained according to the maximum value of the bridge arm current rising rate and the maximum voltage drop of the SVG bridge arm in a steady state and a fault condition.

[0048] Furthermore, the parameter optimization module is specifically used for:

[0049] Simulate and analyze the SVG converter valve to obtain the overvoltage and overcurrent characteristics of the SVG;

[0050] Based on the overvoltage characteristics, determining an overvoltage suppression measure, and updating the number of submodules and the capacitance value of the submodules according to the overvoltage suppression measure;

[0051] Based on the overcurrent characteristics and the overvoltage suppression measures, the bridge arm reactor parameters are updated.

[0052] Compared with the prior art, the beneficial effects of a SVG converter valve parameter configuration method and device provided by the embodiment of the present invention are as follows: by determining the capacity and rated working voltage of the converter valve according to the basic functional requirements of the SVG; determining the type and rated working voltage of the submodule according to the capacity and rated working voltage of the converter valve, and determining the number of submodules in combination with third harmonic injection and harmonic suppression; determining the submodule capacitance value and bridge arm reactor parameters according to the volatility of the submodule capacitor voltage and the harmonic suppression requirements in a steady state; optimizing the number of submodules, capacitance value and bridge arm reactor parameters according to the overvoltage and overcurrent characteristics of the SVG; determining the lightning arrester configuration according to the overvoltage characteristics of the SVG after parameter optimization, and obtaining the converter valve parameter configuration of the SVG, realizing the comprehensive design of the SVG voltage support function, reactive power compensation function and harmonic suppression function, clarifying the corresponding relationship between each SVG function and related parameters, realizing the capacity, rated working voltage, submodule capacitance, number of submodules, bridge arm reactance and auxiliary equipment parameters of the SVG converter valve of the UHV SLCC DC transmission system, avoiding repeated iteration of each converter valve parameter, and improving the system design efficiency and standardization. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 It is a flow chart of a method for configuring parameters of an SVG converter valve provided by an embodiment of the present invention;

[0054] Figure 2 It is a structural schematic diagram of an SVG converter valve parameter configuration device provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0055] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0056] See also Figure 1 , Figure 1 The present invention provides a flow chart of a method for configuring SVG converter valve parameters. The method for configuring SVG converter valve parameters is applied to an ultra-high voltage SLCC direct current transmission system, and the method includes:

[0057] S1: Determine the capacity and rated operating voltage of the converter valve according to the basic functional requirements of the static VAR generator SVG.

[0058] As one of the optional embodiments, the basic functional requirements of SVG include:

[0059] After a fault occurs in the receiving grid, the AC bus voltage of the phase-commutating converter is supported for a short period of time;

[0060] While offsetting the reactive power consumption of the converter transformer and the phase-commutation converter, it also meets the reactive power demand of the AC power grid;

[0061] The harmonic components of the AC power grid are controlled not to flow into the phase-commutating converter; the harmonic components are obtained by investigating the harmonic components of the AC power grid based on the topological structure of the UHV SLCC DC power transmission system.

[0062] Specifically, when designing the SVG converter valve parameters for the UHV SLCC DC transmission system, the basic functional requirements of the SVG are first determined, and the SVG converter valve capacity and rated operating voltage are designed based on the basic functional requirements of the SVG. The converter valve capacity refers to the maximum reactive power that the SVG can provide. It is necessary to ensure that the reactive power compensation capability provided by the SVG matches the system requirements, meets the load requirements and maintains voltage stability. The rated operating voltage of the converter valve needs to match the system voltage level to ensure the stable operation of the SVG.

[0063] Furthermore, the basic functional requirements of SVG include: voltage support, reactive power compensation, harmonic suppression and other functions.

[0064] Among them, the voltage support capability of SVG should be based on the demand of the receiving power grid, so that it can be designed to support the LCC AC bus voltage in a short time after a fault occurs in the receiving power grid; the reactive power compensation capability of SVG should be based on the reactive power demand of the AC power grid, so that it can offset the reactive power consumption of the converter transformer and LCC while meeting the reactive power demand of the AC power grid; the harmonic suppression function of SVG should be based on the topology of the UHV SLCC system, investigate the main harmonic components of the AC power grid, and design it to control the harmonic components from flowing into the LCC.

[0065] Furthermore, when investigating the main harmonic components of the AC power grid, it is necessary to investigate the content of each characteristic harmonic current, including the 11th, 13th, 23rd, and 25th characteristic harmonics.

[0066] S2: Determine the type and rated operating voltage of the submodule according to the capacity and rated operating voltage of the converter valve, and determine the number of submodules in combination with the third harmonic injection capability and harmonic suppression capability of the SVG.

[0067] As one of the optional embodiments, the type and rated operating voltage of the submodule are determined according to the capacity and rated operating voltage of the converter valve, and the number of submodules is determined in combination with the third harmonic injection capability and harmonic suppression capability of the SVG, including:

[0068] The rated current of the bridge arm is calculated according to the capacity and rated working voltage of the converter valve;

[0069] Determining the specifications of the insulated gate bipolar transistor according to the rated current of the bridge arm;

[0070] Determining the type and rated operating voltage of the submodule according to the rated current of the bridge arm and the specifications of the insulated gate bipolar transistor;

[0071] According to the rated operating voltage of the submodule, the number of submodules of the bridge arm under the rated state is calculated;

[0072] Based on the influence of the third harmonic injection capability and harmonic suppression capability of the SVG on the number of sub-modules, the number of sub-modules is corrected to obtain a corrected number of sub-modules.

[0073] Specifically, the rated current flowing through the bridge arm is calculated according to the rated capacity of the SVG converter valve and the rated operating voltage on the valve side. Then, according to the rated current of the bridge arm, an IGBT (insulated gate bipolar transistor) that meets the current is selected, and the specifications and selection of the IGBT are clarified. According to the current and voltage tolerance of the selected IGBT and the rated current of the bridge arm, the submodule type (such as half-bridge, full-bridge, or multi-level module) is selected. According to the submodule type and IGBT specifications, the rated operating voltage of the submodule is determined. Then, based on the rated operating voltage of the selected type of submodule, the number of submodules required for the bridge arm converter valve under the rated state is calculated, and the number of submodules is corrected by considering the influence of functions such as third harmonic injection and harmonic suppression on the number of submodules put into use. Among them, after the third harmonic is injected, the range of the system modulation ratio changes from 0.75~0.95 to 0.85~1.05, and the upper limit of the number of submodules put into use under the same transmission capacity will be reduced. The number of submodules should be corrected according to the maximum number of submodules put into use after the reduction to improve the utilization rate of the submodules.

[0074] S3: Determine the submodule capacitance value and the bridge arm reactor parameters according to the fluctuation of the submodule capacitor voltage in a steady state and the harmonic suppression requirement of the SVG.

[0075] As one of the optional embodiments, the determining of the submodule capacitance value and the bridge arm reactor parameters according to the fluctuation of the submodule capacitance voltage in a steady state and the harmonic suppression requirement of the SVG includes:

[0076] According to the fluctuation rate limit of the submodule capacitor voltage in steady state, the required submodule capacitance value in steady state is calculated;

[0077] According to the valve-controlled overcurrent protection setting value, the device overcurrent tolerance and the protection action delay, the maximum bridge arm current rise rate allowed by the SVG is calculated;

[0078] The bridge arm reactor parameters are obtained according to the maximum value of the bridge arm current rising rate and the maximum voltage drop of the SVG bridge arm in a steady state and a fault condition.

[0079] S4: According to the overvoltage and overcurrent characteristics of the SVG, the number of submodules, the capacitance values ​​of the submodules and the parameters of the bridge arm reactor are optimized to obtain the SVG after parameter optimization.

[0080] As one of the optional embodiments, the optimizing the number of submodules, the capacitance value of the submodules and the parameters of the bridge arm reactor according to the overvoltage and overcurrent characteristics of the SVG includes:

[0081] Simulate and analyze the SVG converter valve to obtain the overvoltage and overcurrent characteristics of the SVG;

[0082] Based on the overvoltage characteristics, determining an overvoltage suppression measure, and updating the number of submodules and the capacitance value of the submodules according to the overvoltage suppression measure;

[0083] Based on the overcurrent characteristics and the overvoltage suppression measures, the bridge arm reactor parameters are updated.

[0084] Specifically, the overvoltage and overcurrent characteristics of the SVG converter valve are simulated and analyzed, and the number of submodules and capacitance values ​​are updated based on the overvoltage analysis results and iterative overvoltage suppression measures (such as increasing the submodule capacitance, increasing the number of submodules, etc.); based on the overcurrent analysis results and overvoltage suppression measures, the number of submodules and capacitance values ​​are updated so that the system can effectively suppress overvoltage and overcurrent.

[0085] S5: According to the overvoltage characteristics of the SVG after the parameter optimization, the arrester configuration position and parameters are determined to obtain the converter valve parameter configuration of the SVG.

[0086] As one of the optional embodiments, determining the configuration position and parameters of the arrester according to the overvoltage characteristics of the SVG after the parameter optimization includes:

[0087] Performing simulation analysis on the SVG after parameter optimization to obtain an overvoltage condition of the SVG after parameter optimization under an extreme overvoltage condition;

[0088] According to the overvoltage situation and the requirements of the converter valve equipment, the configuration location and parameters of the lightning arrester are determined.

[0089] Specifically, based on the updated primary equipment parameters (i.e., the number of submodules and capacitance values, and the bridge arm reactor parameters), the system faults are simulated and traversed to obtain the extreme overvoltage conditions of the converter valve. According to the overvoltage conditions of the converter valve submodules under the most severe faults, the arrester configuration position and parameters are determined, and the converter valve overvoltage conditions are rechecked. The arrester parameters are adjusted according to the overvoltage suppression effect until the converter valve equipment requirements are met. Among them, system faults include SVG external faults and SVG internal faults. SVG external faults must cover faults that may cause large fluctuations in the valve side voltage of the converter transformer. SVG internal faults must include neutral point grounding, single-phase grounding between the bridge arm reactor and the valve, two-phase grounding, and three-phase grounding faults.

[0090] The above steps can realize the comprehensive design process of SVG converter valve capacity, rated working voltage, submodule capacitance, number of submodules, bridge arm reactance, and auxiliary equipment parameters (lightning arrester, etc.) of the UHV SLCC DC transmission system, avoiding repeated iterations of the converter valve parameters and improving the system design efficiency and standardization.

[0091] In a specific example, a UHV DC transmission project with a voltage level of ±800kV, a transmission power of 8GW and SLCC at the sending end is taken as an example.

[0092] First, the SVG converter valve capacity and rated operating voltage are designed according to the basic functional requirements of SVG. The basic functional requirements of SVG include voltage support, reactive power compensation, harmonic suppression and other functions. The SVG capacity of this project is designed to be 550MVA, the reactive power of the AC grid is zeroed, and the SVG is designed to have the ability to suppress the 11th, 13th, 23rd, and 25th characteristic harmonics. The rated operating voltage of the valve side of the SLCC system converter transformer is 153.2kV ​​(line voltage), and the rated operating voltage of the SVG is determined to be 88.45kV.

[0093] Furthermore, the type of converter valve submodule is determined, and the rated operating voltage and number of submodules are designed. The rated current flowing through the bridge arm is 2.07kA, and a 4.5kV / 3kA full-bridge IGBT is selected. According to the device capability, the rated operating voltage of the submodule is set to 2.4kV. Considering the impact of third harmonic injection, harmonic suppression and other functions on the number of submodules, 83 submodules are set for each bridge arm.

[0094] Furthermore, the submodule capacitance value and bridge arm reactor parameters are designed. According to the 10% submodule capacitance voltage fluctuation rate limit of the project, the submodule capacitance is selected as 18mF; according to the valve-controlled overcurrent protection setting (4.8kA), the device overcurrent tolerance (6kA), and the protection action delay (150μs), the maximum bridge arm current rise rate allowed by SVG is calculated to be 8A / μs. Combined with the maximum voltage drop of SVG bridge arm in steady state and fault conditions of 800kV, the bridge arm reactor is determined to be 15mH.

[0095] Furthermore, the overvoltage and overcurrent characteristics of the SVG converter valve were simulated and analyzed to optimize the converter valve parameters. For this project, the overvoltage suppression effects of increasing the submodule capacitance and adjusting the number of submodules were not ideal, so an additional lightning arrester was selected for overvoltage suppression.

[0096] Finally, based on the updated primary equipment parameter simulation and traversal system faults, the extreme operating condition of the converter valve overvoltage is a neutral point grounding fault. After iteration, the valve arrester solution is obtained: normal operating voltage CCOV=200kV, charge rate is 0.8, 20 columns are connected in parallel, the residual voltage is 314kV, and the coordinated current is 4kA. At this time, the maximum overvoltage of the converter valve submodule is 4.04kV, and the energy is 2.2MJ. The SVG converter valve parameter configuration of the SLCC system is completed.

[0097] The embodiment of the present invention determines the capacity and rated working voltage of the converter valve according to the basic functional requirements of SVG; determines the type and rated working voltage of the submodule according to the capacity and rated working voltage of the converter valve, and determines the number of submodules in combination with third harmonic injection and harmonic suppression; determines the submodule capacitance value and bridge arm reactor parameters according to the volatility of the submodule capacitor voltage and the harmonic suppression requirements in a steady state; optimizes the number of submodules, capacitance value and bridge arm reactor parameters according to the overvoltage and overcurrent characteristics of SVG; determines the lightning arrester configuration according to the overvoltage characteristics of SVG after parameter optimization, and obtains the converter valve parameter configuration of SVG, thereby realizing the comprehensive design of SVG voltage support function, reactive power compensation function and harmonic suppression function, clarifying the corresponding relationship between each function of SVG and related parameters, realizing the comprehensive design process of the capacity, rated working voltage, submodule capacitance, number of submodules, bridge arm reactor and auxiliary equipment parameters of SVG converter valve of ultra-high voltage SLCC direct current transmission system, avoiding repeated iteration of each converter valve parameter, and improving the system design efficiency and standardization.

[0098] Correspondingly, the present invention also provides an SVG converter valve parameter configuration device, which can implement all the processes of the SVG converter valve parameter configuration method in the above embodiment.

[0099] See also Figure 2 , Figure 2 The SVG converter valve parameter configuration device is applied to a UHV SLCC direct current transmission system, and the device comprises:

[0100] The converter valve capacity module 201 is used to determine the capacity and rated working voltage of the converter valve according to the basic functional requirements of the static VAR generator SVG;

[0101] A submodule selection module 202 is used to determine the type and rated operating voltage of the submodule according to the capacity and rated operating voltage of the converter valve, and determine the number of submodules in combination with the third harmonic injection capability and harmonic suppression capability of the SVG;

[0102] The submodule capacitor module 203 is used to determine the submodule capacitor value and the bridge arm reactor parameters according to the volatility of the submodule capacitor voltage in a steady state and the harmonic suppression requirement of the SVG;

[0103] A parameter optimization module 204 is used to optimize the number of submodules, the capacitance value of the submodules and the bridge arm reactor parameters according to the overvoltage and overcurrent characteristics of the SVG to obtain the SVG after parameter optimization;

[0104] The arrester configuration module 205 is used to determine the arrester configuration position and parameters according to the overvoltage characteristics of the SVG after the parameter optimization, and obtain the converter valve parameter configuration of the SVG.

[0105] Preferably, the submodule selection module 202 is specifically used for:

[0106] The rated current of the bridge arm is calculated according to the capacity and rated working voltage of the converter valve;

[0107] Determining the specifications of the insulated gate bipolar transistor according to the rated current of the bridge arm;

[0108] Determining the type and rated operating voltage of the submodule according to the rated current of the bridge arm and the specifications of the insulated gate bipolar transistor;

[0109] According to the rated operating voltage of the submodule, the number of submodules of the bridge arm under the rated state is calculated;

[0110] Based on the influence of the third harmonic injection capability and harmonic suppression capability of the SVG on the number of sub-modules, the number of sub-modules is corrected to obtain a corrected number of sub-modules.

[0111] Preferably, the submodule capacitor module 203 is specifically used for:

[0112] According to the fluctuation rate limit of the submodule capacitor voltage in steady state, the required submodule capacitance value in steady state is calculated;

[0113] According to the valve-controlled overcurrent protection setting value, the device overcurrent tolerance and the protection action delay, the maximum bridge arm current rise rate allowed by the SVG is calculated;

[0114] The bridge arm reactor parameters are obtained according to the maximum value of the bridge arm current rising rate and the maximum voltage drop of the SVG bridge arm in a steady state and a fault condition.

[0115] Preferably, the basic functional requirements of SVG include:

[0116] After a fault occurs in the receiving grid, the AC bus voltage of the phase-commutating converter is supported for a short period of time;

[0117] While offsetting the reactive power consumption of the converter transformer and the phase-commutation converter, it also meets the reactive power demand of the AC power grid;

[0118] The harmonic components of the AC power grid are controlled not to flow into the phase-commutating converter; the harmonic components are obtained by investigating the harmonic components of the AC power grid based on the topological structure of the UHV SLCC DC power transmission system.

[0119] Preferably, the parameter optimization module 204 is specifically used for:

[0120] Simulate and analyze the SVG converter valve to obtain the overvoltage and overcurrent characteristics of the SVG;

[0121] Based on the overvoltage characteristics, determining an overvoltage suppression measure, and updating the number of submodules and the capacitance value of the submodules according to the overvoltage suppression measure;

[0122] Based on the overcurrent characteristics and the overvoltage suppression measures, the bridge arm reactor parameters are updated.

[0123] Preferably, the lightning arrester configuration module 205 is specifically used for:

[0124] Performing simulation analysis on the SVG after parameter optimization to obtain an overvoltage condition of the SVG after parameter optimization under an extreme overvoltage condition;

[0125] According to the overvoltage situation and the requirements of the converter valve equipment, the configuration location and parameters of the lightning arrester are determined.

[0126] In the specific implementation, the working principle, control process and technical effect achieved by the SVG converter valve parameter configuration device provided in the embodiment of the present invention are the same as those of the SVG converter valve parameter configuration method in the above embodiment, and will not be repeated here.

[0127] The embodiment of the present invention provides a SVG converter valve parameter configuration method and device, which has the beneficial effects of: determining the capacity and rated working voltage of the converter valve according to the basic functional requirements of SVG; determining the type and rated working voltage of the submodule according to the capacity and rated working voltage of the converter valve, and determining the number of submodules in combination with third harmonic injection and harmonic suppression; determining the submodule capacitance value and bridge arm reactor parameters according to the volatility of the submodule capacitor voltage and the harmonic suppression requirements in a steady state; optimizing the number of submodules, capacitance value and bridge arm reactor parameters according to the overvoltage and overcurrent characteristics of SVG; determining the lightning arrester configuration according to the overvoltage characteristics of SVG after parameter optimization, and obtaining the converter valve parameter configuration of SVG, realizing the comprehensive design of SVG voltage support function, reactive power compensation function and harmonic suppression function, clarifying the corresponding relationship between each function of SVG and related parameters, realizing the comprehensive design process of capacity, rated working voltage, submodule capacitance, number of submodules, bridge arm reactance and auxiliary equipment parameters of SVG converter valve of ultra-high voltage SLCC direct current transmission system, avoiding repeated iteration of each converter valve parameter, and improving system design efficiency and standardization.

[0128] The above is a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A method for configuring SVG converter valve parameters, characterized in that: Applied to an ultra-high voltage SLCC direct current transmission system, the method comprises: Determine the capacity and rated operating voltage of the converter valve according to the basic functional requirements of the static VAR generator SVG; Determine the type and rated operating voltage of the submodule according to the capacity and rated operating voltage of the converter valve, and determine the number of submodules in combination with the third harmonic injection capability and harmonic suppression capability of the SVG; Determine the submodule capacitance value and bridge arm reactor parameters according to the fluctuation of the submodule capacitor voltage in a steady state and the harmonic suppression requirement of the SVG; According to the overvoltage and overcurrent characteristics of the SVG, the number of submodules, the capacitance value of the submodules and the parameters of the bridge arm reactor are optimized to obtain the SVG after parameter optimization; According to the overvoltage characteristics of the SVG after the parameter optimization, the arrester configuration position and parameters are determined to obtain the converter valve parameter configuration of the SVG; The basic functional requirements of SVG include: After a fault occurs in the receiving grid, the AC bus voltage of the phase-commutating converter is supported for a short period of time; While offsetting the reactive power consumption of the converter transformer and the phase-commutation converter, it also meets the reactive power demand of the AC power grid; The harmonic components of the AC power grid are controlled not to flow into the phase-commutating converter; the harmonic components are obtained by investigating the harmonic components of the AC power grid based on the topological structure of the UHV SLCC DC power transmission system.

2. The SVG converter valve parameter configuration method according to claim 1, characterized in that: The method of determining the type and rated operating voltage of the submodule according to the capacity and rated operating voltage of the converter valve, and determining the number of submodules in combination with the third harmonic injection capability and harmonic suppression capability of the SVG, includes: The rated current of the bridge arm is calculated according to the capacity and rated working voltage of the converter valve; Determining the specifications of the insulated gate bipolar transistor according to the rated current of the bridge arm; Determining the type and rated operating voltage of the submodule according to the rated current of the bridge arm and the specifications of the insulated gate bipolar transistor; According to the rated operating voltage of the submodule, the number of submodules of the bridge arm under the rated state is calculated; Based on the influence of the third harmonic injection capability and harmonic suppression capability of the SVG on the number of sub-modules, the number of sub-modules is corrected to obtain a corrected number of sub-modules.

3. The SVG converter valve parameter configuration method according to claim 1, characterized in that: The determining of the submodule capacitance value and the bridge arm reactor parameters according to the fluctuation of the submodule capacitance voltage in a steady state and the harmonic suppression requirement of the SVG includes: According to the fluctuation rate limit of the submodule capacitor voltage in steady state, the required submodule capacitance value in steady state is calculated; According to the valve-controlled overcurrent protection setting value, the device overcurrent tolerance and the protection action delay, the maximum bridge arm current rise rate allowed by the SVG is calculated; The bridge arm reactor parameters are obtained according to the maximum value of the bridge arm current rising rate and the maximum voltage drop of the SVG bridge arm in a steady state and a fault condition.

4. The SVG converter valve parameter configuration method according to claim 1, characterized in that: The optimizing the number of submodules, the capacitance value of the submodules and the parameters of the bridge arm reactor according to the overvoltage and overcurrent characteristics of the SVG includes: Simulate and analyze the SVG converter valve to obtain the overvoltage and overcurrent characteristics of the SVG; Based on the overvoltage characteristics, determining an overvoltage suppression measure, and updating the number of submodules and the capacitance value of the submodules according to the overvoltage suppression measure; Based on the overcurrent characteristics and the overvoltage suppression measures, the bridge arm reactor parameters are updated.

5. The SVG converter valve parameter configuration method according to claim 1, characterized in that: The step of determining the configuration position and parameters of the arrester according to the overvoltage characteristics of the SVG after the parameter optimization includes: Performing simulation analysis on the SVG after parameter optimization to obtain an overvoltage condition of the SVG after parameter optimization under an extreme overvoltage condition; According to the overvoltage situation and the requirements of the converter valve equipment, the configuration location and parameters of the lightning arrester are determined.

6. A SVG converter valve parameter configuration device, characterized in that: Applied to the UHV SLCC DC transmission system, the device comprises: The converter valve capacity module is used to determine the capacity and rated working voltage of the converter valve according to the basic functional requirements of the static VAR generator SVG; A submodule selection module, used to determine the type and rated operating voltage of the submodule according to the capacity and rated operating voltage of the converter valve, and determine the number of submodules in combination with the third harmonic injection capability and harmonic suppression capability of the SVG; A submodule capacitor module, used to determine the submodule capacitor value and bridge arm reactor parameters according to the volatility of the submodule capacitor voltage in a steady state and the harmonic suppression requirements of the SVG; A parameter optimization module, used to optimize the number of submodules, the capacitance value of the submodules and the bridge arm reactor parameters according to the overvoltage and overcurrent characteristics of the SVG, so as to obtain the SVG after parameter optimization; A lightning arrester configuration module, used to determine the lightning arrester configuration position and parameters according to the overvoltage characteristics of the SVG after the parameter optimization, and obtain the converter valve parameter configuration of the SVG; The basic functional requirements of SVG include: After a fault occurs in the receiving grid, the AC bus voltage of the phase-commutating converter is supported for a short period of time; While offsetting the reactive power consumption of the converter transformer and the phase-commutation converter, it also meets the reactive power demand of the AC power grid; The harmonic components of the AC power grid are controlled not to flow into the phase-commutating converter; the harmonic components are obtained by investigating the harmonic components of the AC power grid based on the topological structure of the UHV SLCC DC power transmission system.

7. The SVG converter valve parameter configuration device according to claim 6, characterized in that: The submodule selection module is specifically used for: The rated current of the bridge arm is calculated according to the capacity and rated working voltage of the converter valve; Determining the specifications of the insulated gate bipolar transistor according to the rated current of the bridge arm; Determining the type and rated operating voltage of the submodule according to the rated current of the bridge arm and the specifications of the insulated gate bipolar transistor; According to the rated operating voltage of the submodule, the number of submodules of the bridge arm under the rated state is calculated; Based on the influence of the third harmonic injection capability and harmonic suppression capability of the SVG on the number of sub-modules, the number of sub-modules is corrected to obtain a corrected number of sub-modules.

8. The SVG converter valve parameter configuration device according to claim 6, characterized in that: The submodule capacitor module is specifically used for: According to the fluctuation rate limit of the submodule capacitor voltage in steady state, the required submodule capacitance value in steady state is calculated; According to the valve-controlled overcurrent protection setting value, the device overcurrent tolerance and the protection action delay, the maximum bridge arm current rise rate allowed by the SVG is calculated; The bridge arm reactor parameters are obtained according to the maximum value of the bridge arm current rising rate and the maximum voltage drop of the SVG bridge arm in a steady state and a fault condition.

9. The SVG converter valve parameter configuration device according to claim 6, characterized in that: The parameter optimization module is specifically used for: Simulate and analyze the SVG converter valve to obtain the overvoltage and overcurrent characteristics of the SVG; Based on the overvoltage characteristics, determining an overvoltage suppression measure, and updating the number of submodules and the capacitance value of the submodules according to the overvoltage suppression measure; Based on the overcurrent characteristics and the overvoltage suppression measures, the bridge arm reactor parameters are updated.

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