Double-layer reactive power regulation method and system for sending-end converter station

Abstract

The invention provides a sending-end converter station double-layer reactive power regulation method and system, and the method comprises the steps: adjusting the steady-state reactive power output of a phase modifier according to the voltage of an AC bus and the reactive power exchange capacity of an AC / DC system, and enabling the reactive power exchange capacity of the AC / DC system to be within a dead zone value of a single-group AC filter; if the reactive power output of the phase modifier is adjusted in the steady-state reactive power output range and the reactive power exchange capacity of the AC / DC system cannot be adjusted to be within the dead zone value of the single-group AC filter, switching the AC filter until the reactive power exchange capacity of the AC / DC system is within the dead zone value of the single-group AC filter, and then completing the adjustment; according to the invention, the phase modifier is introduced to participate in the steady-state reactive compensation of the sending end, so that the dynamic characteristics of the phase modifier are ensured, the suppression capability of the phase modifier for transient overvoltage is improved, the switching group number of the AC filter is reduced, the utilization rate of the phase modifier is improved, the service life of the AC filter is prolonged, and the operation economy of the converter station is improved.

Description

Technical Field

[0001] The present invention relates to the field of converter station regulation, and in particular to a double-layer reactive power regulation method and system for a sending-end converter station. Background Art

[0002] In recent years, with the promotion and application of large-capacity and long-distance ultra-high voltage direct current transmission technology, the problem of "strong direct current and weak alternating current" in the power grid has become prominent. The ultra-high voltage direct current transmission system needs to absorb about 40%-60% of its transmission power during normal operation. In order to improve the stability of the low-voltage direct current operation at the weak sending end, it is necessary to install additional reactive power compensation devices. There are reactive power compensation equipment such as synchronous phase condensers, filter capacitors and low-voltage reactors in the direct current converter station. In the current technical scheme, the synchronous phase condensers are mainly used for dynamic reactive power support and do not participate in the steady-state voltage regulation of the system in principle. The reactive power loss of the direct current converter station is mainly compensated by the filter capacitor group. The direct current control and protection system switches the filter capacitor group through voltage control or reactive power control, so that the AC bus voltage of the converter station and the reactive exchange amount of the AC and DC system are within the allowable range. The existing technology has the problems of waste of the steady-state phase condenser capacity and frequent switching of the AC filter affecting the service life. It is necessary to optimize the reactive power configuration scheme of the sending-end converter station and the reactive power regulation method under steady state, reduce the number of AC filter groups and the switching times, and maintain the voltage stability during normal operation. Summary of the invention

[0003] In order to overcome the above-mentioned deficiencies of the prior art, the present invention proposes a double-layer reactive power regulation method for a sending-end converter station, comprising:

[0004] According to the AC bus voltage and the reactive exchange amount of the AC / DC system, the steady-state reactive output of the phase regulator is adjusted to make the reactive exchange amount of the AC / DC system within the dead zone value of a single group of AC filters;

[0005] If the phase regulator cannot adjust the reactive output of the AC / DC system to within the dead zone value of a single AC filter by adjusting the reactive output within the steady-state reactive output range, the AC filter is switched on and off until the reactive exchange of the AC / DC system is within the dead zone value of a single AC filter and the adjustment is completed;

[0006] The steady-state reactive power output range of the phase regulator is set according to the capacity of a single group of AC filters in the converter station and the dead zone value.

[0007] Preferably, the step of adjusting the steady-state reactive output of the phase regulator according to the AC bus voltage and the reactive exchange amount of the AC / DC system so that the reactive exchange amount of the AC / DC system is within the dead zone value of a single group of AC filters includes:

[0008] The AC bus voltage is obtained to obtain the reactive power output of a single group of AC filters;

[0009] Calculate the current reactive exchange amount of the AC / DC system based on the reactive output of a single set of AC filters;

[0010] Based on the current reactive exchange amount of the AC / DC system and the reactive output of a single group of AC filters, the reactive exchange amount of the AC / DC system is adjusted within the dead zone value of the single group of AC filters by adjusting the reactive output of the phase regulator within the steady-state output range.

[0011] Preferably, the calculation formula for the reactive output of the single group of AC filters is:

[0012]

[0013] The Q filt is the reactive power output of a single AC filter, U p is the actual voltage of the AC bus, U N is the rated voltage of the AC bus, Q filtN It is the rated capacity of a single set of AC filters.

[0014] Preferably, the calculation formula for the reactive exchange amount of the current AC / DC system is:

[0015] Q exc =Q sc +Q ac +nQ filt -Q conv

[0016] The Q exc is the reactive power exchange of the current AC / DC system, Q sc Q is the reactive power output of the phase regulator. ac Inject reactive power into AC and DC systems, Q filt is the reactive power output of a single AC filter, n is the number of AC filters in operation, Q conv is the reactive power consumption of the converter station.

[0017] Preferably, the calculation formula for the adjusted reactive exchange amount of the AC / DC system is:

[0018] Q′ exc =Q′ sc +Q ac +nQ filt -Q conv

[0019] Where Q' exc is the reactive exchange amount of the AC / DC system after adjustment, Q' sc Q is the reactive power output after phase adjustment. ac Inject reactive power into AC and DC systems, Q filt is the reactive power output of a single AC filter, n is the number of AC filters in operation, Q convis the reactive power consumption of the converter station.

[0020] Preferably, if the reactive output of the phase regulator cannot be adjusted to adjust the reactive exchange amount of the AC / DC system to within the dead zone value of a single group of AC filters by adjusting the reactive output of the phase regulator within the steady-state reactive output range, the AC filter is switched on and off until the reactive exchange amount of the AC / DC system is within the dead zone value of a single group of AC filters, including:

[0021] If the reactive output of the phase regulator cannot adjust the reactive exchange amount of the AC / DC system to within the dead zone value of a single group of AC filters by adjusting the reactive output of the phase regulator within the steady-state reactive output range, the reactive exchange amount of the AC / DC system after adjustment is obtained;

[0022] Based on the adjusted reactive exchange amount of the AC and DC systems, the difference between the actual value of the reactive exchange amount between the AC and DC systems after the phase shifter adjustment and the dead zone value of a single group of AC filters is calculated;

[0023] The number of AC filters to be switched is estimated based on the difference, and the AC filters are switched group by group, and the reactive exchange amount between the AC and DC systems is adjusted until the reactive exchange amount between the AC and DC systems is within the dead zone value of a single group of AC filters.

[0024] Preferably, the reactive exchange amount between the AC and DC systems during the regulation process is calculated as follows:

[0025] Q″ exc =Q′ sc +Q ac +(n±m)Q filt -Q conv

[0026] The Q” exc Q' is the reactive exchange between AC and DC systems during the switching process of AC filter. sc Q is the reactive power output after phase adjustment. ac Inject reactive power into the AC / DC system, Q filt is the reactive compensation of a single AC filter, n is the number of AC filter groups in operation, m is the number of AC filter groups expected to be put into operation or removed, Q conv is the reactive power consumption of the converter station.

[0027] Based on the same inventive concept, the present invention also provides a double-layer reactive power regulation system for a sending-end converter station, comprising:

[0028] Phase regulator adjustment module: used to adjust the steady-state reactive output of the phase regulator according to the AC bus voltage and the reactive exchange amount of the AC / DC system, so that the reactive exchange amount of the AC / DC system is within the dead zone value of a single group of AC filters;

[0029] AC filter switching module: when the phase regulator cannot adjust the reactive output of the AC / DC system to the dead zone value of a single group of AC filters by adjusting the reactive output within the steady-state reactive output range, the AC filter is switched on and off until the reactive exchange amount of the AC / DC system is within the dead zone value of a single group of AC filters and the adjustment is completed;

[0030] The steady-state reactive power output range of the phase regulator is set according to the capacity of a single group of AC filters in the converter station and the dead zone value.

[0031] Preferably, the phase regulator adjustment module is specifically used for:

[0032] The AC bus voltage is obtained to obtain the reactive power output of a single group of AC filters;

[0033] Calculate the current reactive exchange amount of the AC / DC system based on the reactive output of a single set of AC filters;

[0034] Based on the current reactive exchange amount of the AC / DC system and the reactive output of a single group of AC filters, the reactive exchange amount of the AC / DC system is adjusted within the dead zone value of the single group of AC filters by adjusting the reactive output of the phase regulator within the steady-state output range.

[0035] Preferably, the calculation formula for the reactive output of a single group of AC filters in the phase regulator adjustment module is:

[0036]

[0037] The Q filt is the reactive power output of a single AC filter, U p is the actual voltage of the AC bus, U N is the rated voltage of the AC bus, Q filtN It is the rated capacity of a single set of AC filters.

[0038] Preferably, the calculation formula for the reactive exchange amount of the current AC / DC system in the phase regulator adjustment module is:

[0039] Q exc =Q sc +Q ac +nQ filt -Q conv

[0040] The Q exc is the reactive power exchange of the current AC / DC system, Q sc Q is the reactive power output of the phase regulator. ac Inject reactive power into AC and DC systems, Q filt is the reactive power output of a single AC filter, n is the number of AC filters in operation, Q conv is the reactive power consumption of the converter station.

[0041] Preferably, the calculation formula for the reactive exchange amount of the AC / DC system adjusted in the phase regulator adjustment module is:

[0042] Q′ exc =Q′ sc +Q ac +nQ filt -Q conv

[0043] The Q ’ exc is the reactive exchange amount of the AC / DC system after adjustment, Q ’ sc Q is the reactive power output after phase adjustment. ac Inject reactive power into AC and DC systems, Q filt is the reactive power output of a single AC filter, n is the number of AC filters in operation, Q conv is the reactive power consumption of the converter station.

[0044] Preferably, the AC filter switching module is specifically used for:

[0045] If the phase regulator in the phase regulator adjustment module adjusts the reactive output of the phase regulator within the steady-state reactive output range and cannot adjust the reactive exchange amount of the AC / DC system to within the dead zone value of a single group of AC filters, the adjusted reactive exchange amount of the AC / DC system is obtained;

[0046] Based on the adjusted reactive exchange amount of the AC and DC systems, the difference between the actual value of the reactive exchange amount between the AC and DC systems after the phase shifter adjustment and the dead zone value of a single group of AC filters is calculated;

[0047] The number of AC filters to be switched is estimated based on the difference, and the AC filters are switched group by group, and the reactive exchange amount between the AC and DC systems is adjusted until the reactive exchange amount between the AC and DC systems is within the dead zone value of a single group of AC filters.

[0048] Preferably, the calculation formula for the reactive exchange amount between the AC and DC systems during the regulation process in the AC filter switching module is:

[0050] Q ” exc =Q sc +Q ac +(n±m)Q filt -Q conv

[0051] The Q ” exc Q is the reactive exchange between AC and DC systems during the switching adjustment of AC filters. ’ sc Q is the reactive power output after phase adjustment.ac Inject reactive power into the AC / DC system, Q filt is the reactive compensation of a single AC filter, n is the number of AC filter groups in operation, m is the number of AC filter groups expected to be put into operation or removed, Q conv is the reactive power consumption of the converter station.

[0052] Based on the same inventive concept, the present invention further provides a computer device, characterized in that it includes:

[0053] one or more processors;

[0054] A memory for storing one or more programs;

[0055] When the one or more programs are executed by the one or more processors, a double-layer reactive power regulation method for a sending-end converter station as described in any one of the above items is implemented.

[0056] Based on the same inventive concept, the present invention also provides a computer-readable storage medium, characterized in that a computer program is stored thereon, and when the computer program is executed, a double-layer reactive power regulation method for a sending-end converter station as described in any one of the above items is implemented.

[0057] Compared with the closest prior art, the present invention has the following beneficial effects:

[0058] The present invention provides a double-layer reactive power regulation method and system for a sending-end converter station, comprising: regulating the steady-state reactive power output of a phase regulator according to the AC bus voltage and the reactive power exchange amount of an AC / DC system, so that the reactive power exchange amount of the AC / DC system is within the dead zone value of a single group of AC filters; if the phase regulator cannot adjust the reactive power exchange amount of the AC / DC system to the dead zone value of a single group of AC filters by regulating the reactive power output within the steady-state reactive power output range, switching the AC filter until the reactive power exchange amount of the AC / DC system is within the dead zone value of a single group of AC filters, and then completing the regulation; the present invention introduces a phase regulator to participate in the steady-state reactive power compensation at the sending end, while ensuring the dynamic characteristics of the phase regulator, reducing the number of switched groups of the AC filter, improving the utilization rate of the phase regulator, extending the service life of the AC filter, and improving the economy of the converter station operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 A flow chart of a double-layer reactive power regulation method for a sending-end converter station provided by the present invention;

[0060] Figure 2 A detailed flow chart of a double-layer reactive power regulation method for a sending-end converter station provided by the present invention;

[0061] Figure 3 A diagram of the reactive power regulation process of the first layer provided by the present invention;

[0062] Figure 4 A diagram showing the output of a three-phase short-circuit-controlled camera provided by the present invention;

[0063] Figure 5 The AC bus voltage diagram at the sending end of the three-phase short circuit provided by the present invention;

[0064] Figure 6 A diagram showing the output of a camera reduced by a single-phase ground short circuit provided by the present invention;

[0065] Figure 7 The AC bus voltage diagram at the sending end of the single-phase ground short circuit provided by the present invention;

[0066] Figure 8 A structural diagram of a double-layer reactive power regulation system for a sending-end converter station provided by the present invention. DETAILED DESCRIPTION

[0067] The specific implementation modes of the present invention are further described in detail below with reference to the accompanying drawings.

[0068] Embodiment 1:

[0069] The present invention proposes a double-layer reactive power regulation method for a sending-end converter station, the flow chart of which is as follows: Figure 1 The detailed adjustment process diagram is shown in Figure 2 As shown, including:

[0070] Step 1: According to the AC bus voltage and the reactive exchange amount of the AC / DC system, the steady-state reactive output of the phase regulator is adjusted to make the reactive exchange amount of the AC / DC system within the dead zone value of a single group of AC filters;

[0071] Step 2: If the phase regulator cannot adjust the reactive output of the AC / DC system to within the dead zone value of a single AC filter by adjusting the reactive output within the steady-state reactive output range, the AC filter is switched on and off until the reactive exchange of the AC / DC system is within the dead zone value of a single AC filter and the adjustment is completed;

[0072] The steady-state reactive power output range of the phase regulator is set according to the capacity of a single group of AC filters in the converter station and the dead zone value.

[0073] Specifically, step 1 includes:

[0074] The AC bus voltage is obtained to obtain the reactive power output of a single group of AC filters;

[0075] Calculate the current reactive exchange amount of the AC / DC system based on the reactive output of a single set of AC filters;

[0076] Based on the current reactive exchange amount of the AC / DC system and the reactive output of a single group of AC filters, the reactive exchange amount of the AC / DC system adjusted by the phase regulator within the steady-state output range is within the dead zone value of the single group of AC filters by adjusting the reactive output of the phase regulator;

[0077] The calculation formula for the reactive output of the single group AC filter is:

[0078]

[0079] The Q filt is the reactive power output of a single AC filter, U p is the actual voltage of the AC bus, U N is the rated voltage of the AC bus, Q filtN It is the rated capacity of a single set of AC filters;

[0080] like Figure 3 The figure shows the first-layer reactive power regulation process diagram, in which the calculation formula of the reactive power exchange amount of the current AC / DC system is:

[0081] Q exc =Q sc +Q ac +nQ filt -Q conv

[0082] The Q exc is the reactive power exchange of the current AC / DC system, Q sc Q is the reactive power output of the phase regulator. ac Inject reactive power into AC and DC systems, Q filt is the reactive power output of a single AC filter, n is the number of AC filters in operation, Q conv is the reactive power consumption of the converter station;

[0083] The calculation formula for the adjusted reactive exchange amount of the AC / DC system is:

[0084] Q′ exc =Q′ sc +Q ac +nQ filt -Q conv

[0085] Where Q' exc is the reactive exchange amount of the AC / DC system after adjustment, Q' sc Q is the reactive power output after phase adjustment. ac Inject reactive power into AC and DC systems, Q filt is the reactive power output of a single AC filter, n is the number of AC filters in operation, Q conv is the reactive power consumption of the converter station;

[0086] Step 2 includes:

[0087] If the reactive output of the phase regulator cannot adjust the reactive exchange amount of the AC / DC system to within the dead zone value of a single group of AC filters by adjusting the reactive output of the phase regulator within the steady-state reactive output range, the reactive exchange amount of the AC / DC system after adjustment is obtained;

[0088] Based on the adjusted reactive exchange amount of the AC and DC systems, the difference between the actual value of the reactive exchange amount between the AC and DC systems after the phase shifter adjustment and the dead zone value of a single group of AC filters is calculated;

[0089] The number of AC filters to be switched is estimated based on the difference, and the AC filters are switched group by group, and the reactive exchange amount between the AC and DC systems is adjusted until the reactive exchange amount between the AC and DC systems is within the dead zone value of a single group of AC filters.

[0090] The calculation formula for the reactive exchange amount between the AC and DC systems during the regulation process is:

[0091] Q″ exc =Q′ sc +Q ac +(n±m)Q filt -Q conv

[0092] The Q” exc Q' is the reactive exchange between AC and DC systems during the switching process of AC filter. sc Q is the reactive power output after phase adjustment. ac Inject reactive power into the AC / DC system, Q filt is the reactive compensation of a single AC filter, n is the number of AC filter groups in operation, m is the number of AC filter groups expected to be put into operation or removed, Q conv is the reactive power consumption of the converter station.

[0093] Embodiment 2:

[0094] The following is a specific embodiment to illustrate a double-layer reactive power regulation method for a sending-end converter station provided by the present invention, which specifically includes:

[0095] A LCC-HVDC simulation model was built in PSCAD, and simulation verification was carried out on the feasibility of the reactive power compensation scheme of the converter station and the effectiveness of the double-layer reactive power adjustment method.

[0096] Firstly, the dynamic characteristics of the phase regulator of the converter station under the reactive power compensation scheme at the sending end are verified. Single-phase grounding short circuit and three-phase short circuit faults are set at the receiving end busbar, and the short circuit time is 0.1s. The dynamic support capacity of the phase regulator under the steady-state output of 0 and the steady-state lagging phase operation and the output of 100Mvar are compared, as well as the voltage stability of the system under the two conditions. Figures 4 to 7 The camera output and the AC bus voltage at the sending end are adjusted down for the two operating modes.

[0097] From the above experiments and graphs, it can be seen that the phase-lag operation of the phase regulator in steady state does not affect the phase regulator's rapid response capability under transient conditions and the voltage stability of the AC system, and can increase the depth of phase-lag operation, which is beneficial to suppress transient overvoltage. The simulation shows that the solution of phase regulator participating in the steady-state reactive power compensation of the sending-end converter station is feasible.

[0098] Then the advantages of the phase regulator participating in the reactive power compensation scheme of the converter station were verified. The input of AC filters in the sending-end converter station under different DC capacities was simulated in PSACAD. In the PSCAD model, the filters required for different reactive power configuration schemes of the sending-end converter station under different DC transmission capacities were compared. Scheme 1 is that only the AC filter provides reactive power compensation, and the rated capacity of a single group of AC filters is 175Mvar. Scheme 2 is that the phase regulator and the AC filter jointly participate in the reactive power compensation task of the converter station, and the rated capacity of a single group of AC filters is the same as that of the scheme. The configuration of AC filters under the two configuration schemes is shown in Table 1 below:

[0099] Table 1 Input of AC filter in the sending-end converter station under different configuration schemes

[0100] DC capacity Solution 1 Solution 2 2000MW 5 groups 4 groups 3000MW 9 groups 8 groups 4000MW 10 groups 9 groups 6000MW 17 groups 16 groups 8000MW 20 groups 19 groups

[0101] As shown in Table 1, at the sending-end converter station, the phase regulator and the AC filter can jointly perform reactive power compensation, which can partially replace the reactive power of the AC filter and reduce the number of AC filter groups. The phase regulator's participation in steady-state reactive power compensation can optimize the current configuration of the AC filter at the sending-end converter station.

[0102] Finally, the effectiveness of the double-layer reactive power adjustment method is verified. The configuration method of reactive power compensation in the PSCAD model is first determined: the rated capacity of a single group of AC filters in the sending-end converter station is 175Mvar, the dead zone value is 65%, and the output of the phase regulator in steady-state operation is set to 120Mvar according to the dead zone value. The steady-state output range is 1 dead zone value above and below, that is, 0-240Mvar. At the same time, after the first layer of reactive power adjustment is completed, the short-term operating range of the phase regulator is -50Mvar—300Mvar.

[0103] Table 2 below shows the AC bus voltage at the sending end and the AC filter action after the AC filter performs reactive power adjustment alone and the double-layer reactive power adjustment method. In the table, U0 refers to the AC bus voltage at the sending end before reactive power adjustment, and U1 refers to the AC bus voltage at the sending end after reactive power adjustment is completed. Scheme 1 is reactive power adjustment of the AC filter alone, and scheme 2 is the double-layer reactive power adjustment method.

[0104] Table 2 AC filter switching times under different reactive power adjustment methods at the sending end converter station

[0105] U0 / pu U1 / pu Solution 1 U1 / pu Solution 2 1.045 1.029 1 time 1.017 1 time 1.045 1.011 2 times 1.017 1 time 1.061 1.042 1 time 1.035 1 time 1.061 1.025 2 times 1.019 2 times 1.071 1.054 1 time 1.049 1 time 1.071 1.038 2 times 1.032 2 times 1.071 1.024 3 times 1.015 3 times 0.931 0.958 1 time 0.969 1 time 0.931 0.978 2 times 0.987 2 times 0.948 0.966 1 time 0.995 1 time 0.948 0.985 2 times 0.995 1 time

[0106] It can be seen from Table 2 that compared with the reactive power adjustment of the AC filter alone, under the double-layer reactive power adjustment method, the phase regulator and the AC filter coordinate the reactive power adjustment, which can ensure that the voltage is within the stable range while reducing the switching times of the AC filter. When the switching times of the AC filter are the same, the AC bus voltage at the sending end is closer to the rated voltage under the double-layer reactive power adjustment method.

[0107] Embodiment 3:

[0108] Based on the same inventive concept, the present invention also provides a double-layer reactive power regulation system for a sending-end converter station, the structure of which is as follows: Figure 8 As shown, including:

[0109] Phase regulator adjustment module: used to adjust the steady-state reactive output of the phase regulator according to the AC bus voltage and the reactive exchange amount of the AC / DC system, so that the reactive exchange amount of the AC / DC system is within the dead zone value of a single group of AC filters;

[0110] AC filter switching module: when the phase regulator cannot adjust the reactive output of the AC / DC system to the dead zone value of a single group of AC filters by adjusting the reactive output within the steady-state reactive output range, the AC filter is switched on and off until the reactive exchange amount of the AC / DC system is within the dead zone value of a single group of AC filters and the adjustment is completed;

[0111] The steady-state reactive power output range of the phase regulator is set according to the capacity of a single group of AC filters in the converter station and the dead zone value.

[0112] The phase regulator adjustment module is specifically used for:

[0113] The AC bus voltage is obtained to obtain the reactive power output of a single group of AC filters;

[0114] Calculate the current reactive exchange amount of the AC / DC system based on the reactive output of a single set of AC filters;

[0115] Based on the current reactive exchange amount of the AC / DC system and the reactive output of a single group of AC filters, the reactive exchange amount of the AC / DC system is adjusted within the dead zone value of the single group of AC filters by adjusting the reactive output of the phase regulator within the steady-state output range.

[0116] The calculation formula for the reactive output of a single group of AC filters in the phase regulator adjustment module is:

[0117]

[0118] The U p is the actual voltage of the AC bus, U N is the rated voltage of the AC bus, Q filtN It is the rated capacity of a single set of AC filters.

[0119] The calculation formula for the reactive exchange amount of the current AC / DC system in the phase-converter adjustment module is:

[0120] Q exc =Q sc +Q ac +nQ filt -Q conv

[0121] The Q sc Q is the reactive power output of the phase regulator. ac Inject reactive power into AC and DC systems, Q filt is the reactive power output of a single AC filter, n is the number of AC filters in operation, Q conv is the reactive power consumption of the converter station.

[0122] The calculation formula for the reactive exchange amount of the AC / DC system adjusted in the phase-converter adjustment module is:

[0123] Q′ exc =Q′ sc +Q ac +nQ filt -Q conv

[0124] Where Q' sc Q is the reactive power output after phase adjustment. ac Inject reactive power into AC and DC systems, Q filt is the reactive power output of a single AC filter, n is the number of AC filters in operation, Q conv is the reactive power consumption of the converter station.

[0125] The AC filter switching module is specifically used for:

[0126] If the phase regulator in the phase regulator adjustment module adjusts the reactive output of the phase regulator within the steady-state reactive output range and cannot adjust the reactive exchange amount of the AC / DC system to within the dead zone value of a single group of AC filters, the adjusted reactive exchange amount of the AC / DC system is obtained;

[0127] Based on the adjusted reactive exchange amount of the AC and DC systems, the difference between the actual value of the reactive exchange amount between the AC and DC systems after the phase shifter adjustment and the dead zone value of a single group of AC filters is calculated;

[0128] The number of AC filters to be switched is estimated based on the difference, and the AC filters are switched group by group, and the reactive exchange amount between the AC and DC systems is adjusted until the reactive exchange amount between the AC and DC systems is within the dead zone value of a single group of AC filters.

[0129] The calculation formula for the reactive exchange amount between the AC and DC systems during the regulation process in the AC filter switching module is:

[0130] Q″ exc=Q′ sc +Q ac +(n±m)Q filt -Q conv

[0131] Where Q' sc Q is the reactive power output after phase adjustment. ac Inject reactive power into the AC / DC system, Q filt is the reactive compensation of a single AC filter, n is the number of AC filter groups in operation, m is the number of AC filter groups expected to be put into operation or removed, Q conv is the reactive power consumption of the converter station.

[0132] Embodiment 4:

[0133] Based on the same inventive concept, the present invention also provides a computer device, which includes a processor and a memory, wherein the memory is used to store a computer program, wherein the computer program includes program instructions, and the processor is used to execute the program instructions stored in the computer storage medium. The processor may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc. It is the computing core and control core of the terminal, which is suitable for implementing one or more instructions, and is specifically suitable for loading and executing one or more instructions in the computer storage medium to implement the corresponding method flow or corresponding function, so as to implement the steps of a double-layer reactive power regulation method of a sending-end converter station in the above embodiment.

[0134] Embodiment 5:

[0135] Based on the same inventive concept, the present invention also provides a storage medium, specifically a computer-readable storage medium (Memory), which is a memory device in a computer device for storing programs and data. It can be understood that the computer-readable storage medium here can include both built-in storage media in a computer device and, of course, extended storage media supported by the computer device. The computer-readable storage medium provides a storage space, which stores the operating system of the terminal. In addition, one or more instructions suitable for being loaded and executed by a processor are also stored in the storage space, and these instructions can be one or more computer programs (including program codes). It should be noted that the computer-readable storage medium here can be a high-speed RAM memory or a non-volatile memory, such as at least one disk memory. The processor can load and execute one or more instructions stored in the computer-readable storage medium to implement the steps of a double-layer reactive power regulation method of a sending-end converter station in the above embodiment.

[0136] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0137] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0138] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1A function specified in one or more boxes.

[0139] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0140] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit its protection scope. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field should understand that after reading the present invention, those skilled in the art can still make various changes, modifications or equivalent substitutions to the specific implementation methods of the application, but these changes, modifications or equivalent substitutions are all within the protection scope of the claims to be approved.

Claims

1. A double-layer reactive power regulation method for a sending-end converter station, characterized in that: The method comprises: According to the AC bus voltage and the reactive exchange amount of the AC / DC system, the steady-state reactive output of the phase regulator is adjusted to make the reactive exchange amount of the AC / DC system within the dead zone value of a single group of AC filters; If the phase regulator cannot adjust the reactive output of the AC / DC system to within the dead zone value of a single AC filter by adjusting the reactive output within the steady-state reactive output range, the AC filter is switched on and off until the reactive exchange of the AC / DC system is within the dead zone value of a single AC filter and the adjustment is completed; The steady-state reactive power output range of the phase regulator is set according to the capacity of a single group of AC filters in the converter station and the dead zone value.

2. The method according to claim 1, characterized in that The method of adjusting the steady-state reactive output of the phase regulator according to the AC bus voltage and the reactive exchange amount of the AC / DC system so that the reactive exchange amount of the AC / DC system is within the dead zone value of a single group of AC filters includes: The AC bus voltage is obtained to obtain the reactive power output of a single group of AC filters; Calculate the current reactive exchange amount of the AC / DC system based on the reactive output of a single set of AC filters; Based on the current reactive exchange amount of the AC / DC system and the reactive output of a single group of AC filters, the reactive exchange amount of the AC / DC system is adjusted within the dead zone value of the single group of AC filters by adjusting the reactive output of the phase regulator within the steady-state output range.

3. The method according to claim 2, characterized in that The calculation formula for the reactive output of the single group AC filter is: The Q filt is the reactive power output of a single AC filter, U p is the actual voltage of the AC bus, U N is the rated voltage of the AC bus, Q filtN It is the rated capacity of a single set of AC filters.

4. The method according to claim 2, characterized in that The calculation formula for the reactive exchange amount of the current AC / DC system is: Q exc =Q sc +Q ac +nQ filt -Q conv The Q exc is the reactive power exchange of the current AC / DC system, Q sc Q is the reactive power output of the phase regulator. ac Inject reactive power into AC and DC systems, Q filt is the reactive power output of a single AC filter, n is the number of AC filters in operation, Q conv is the reactive power consumption of the converter station.

5. The method according to claim 2, characterized in that The calculation formula for the adjusted reactive exchange amount of the AC / DC system is: Q′ exc =Q′ sc +Q ac +nQ filt -Q conv Where Q' exc is the reactive exchange amount of the AC / DC system after adjustment, Q' sc Q is the reactive power output after phase adjustment. ac Inject reactive power into AC and DC systems, Q filt is the reactive power output of a single AC filter, n is the number of AC filters in operation, Q conv is the reactive power consumption of the converter station.

6. The method according to claim 1, characterized in that If the phase regulator cannot adjust the reactive output of the AC / DC system to within the dead zone value of a single group of AC filters by adjusting the reactive output within the steady-state reactive output range, the AC filter is switched on and off until the reactive exchange amount of the AC / DC system is within the dead zone value of the single group of AC filters and the adjustment is completed, including: If the reactive output of the phase regulator cannot adjust the reactive exchange amount of the AC / DC system to within the dead zone value of a single group of AC filters by adjusting the reactive output of the phase regulator within the steady-state reactive output range, the reactive exchange amount of the AC / DC system after adjustment is obtained; Based on the adjusted reactive exchange amount of the AC and DC systems, the difference between the actual value of the reactive exchange amount between the AC and DC systems after the phase shifter adjustment and the dead zone value of a single group of AC filters is calculated; The number of AC filters to be switched is estimated based on the difference, and the AC filters are switched group by group. The reactive exchange amount between the AC and DC systems is adjusted until the reactive exchange amount between the AC and DC systems is within the dead zone value of a single group of AC filters, and then the adjustment is completed.

7. The method according to claim 6, characterized in that The calculation formula for the reactive exchange amount between the AC and DC systems during the regulation process is: Q″ exc =Q′ sc +Q ac +(n±m)Q filt -Q conv The Q ” exc Q is the reactive exchange between AC and DC systems during the switching adjustment of AC filters. ’ sc Q is the reactive power output after phase adjustment. ac Inject reactive power into the AC / DC system, Q filt is the reactive compensation of a single AC filter, n is the number of AC filter groups in operation, m is the number of AC filter groups expected to be put into operation or removed, Q conv is the reactive power consumption of the converter station.

8. A double-layer reactive power regulation system for a sending-end converter station, characterized in that: include: Phase regulator adjustment module: used to adjust the steady-state reactive output of the phase regulator according to the AC bus voltage and the reactive exchange amount of the AC / DC system, so that the reactive exchange amount of the AC / DC system is within the dead zone value of a single group of AC filters; AC filter switching module: when the phase regulator cannot adjust the reactive output of the AC / DC system to the dead zone value of a single group of AC filters by adjusting the reactive output within the steady-state reactive output range, the AC filter is switched on and off until the reactive exchange amount of the AC / DC system is within the dead zone value of a single group of AC filters and the adjustment is completed; The steady-state reactive power output range of the phase regulator is set according to the capacity of a single group of AC filters in the converter station and the dead zone value.

9. The system according to claim 8, characterized in that The phase regulator adjustment module is specifically used for: The AC bus voltage is obtained to obtain the reactive power output of a single group of AC filters; Calculate the current reactive exchange amount of the AC / DC system based on the reactive output of a single set of AC filters; Based on the current reactive exchange amount of the AC / DC system and the reactive output of a single group of AC filters, the reactive exchange amount of the AC / DC system is adjusted within the dead zone value of the single group of AC filters by adjusting the reactive output of the phase regulator within the steady-state output range.

10. The system according to claim 8, characterized in that The AC filter switching module is specifically used for: If the phase regulator in the phase regulator adjustment module adjusts the reactive output of the phase regulator within the steady-state reactive output range and cannot adjust the reactive exchange amount of the AC / DC system to within the dead zone value of a single group of AC filters, the adjusted reactive exchange amount of the AC / DC system is obtained; Based on the adjusted reactive exchange amount of the AC and DC systems, the difference between the actual value of the reactive exchange amount between the AC and DC systems after the phase shifter adjustment and the dead zone value of a single group of AC filters is calculated; The number of AC filters to be switched is estimated based on the difference, and the AC filters are switched group by group, and the reactive exchange amount between the AC and DC systems is adjusted until the reactive exchange amount between the AC and DC systems is within the dead zone value of a single group of AC filters.

11. A computer device, characterized in that: include: one or more processors; A memory for storing one or more programs; When the one or more programs are executed by the one or more processors, a double-layer reactive power regulation method for a sending-end converter station as described in any one of claims 1 to 7 is implemented.

12. A computer-readable storage medium, characterized in that: A computer program is stored thereon, and when the computer program is executed, a double-layer reactive power regulation method for a sending-end converter station as described in any one of claims 1 to 7 is implemented.

Images