An optimized control method and system suitable for CLCC high-voltage direct-current system

Abstract

The application discloses an optimization control method and system suitable for a CLCC high-voltage direct-current system and belongs to the technical field of power systems. The method comprises the following steps: determining the topological structure and control strategy of a sending and receiving end of a high-voltage direct-current system, determining whether an inverter side converter station of the high-voltage direct-current system enters a CLCC working mode based on the topological structure and the control strategy, detecting the effective value of alternating current voltage of a converter bus of the high-voltage direct-current system in real time if the inverter side converter station enters the CLCC working mode, judging whether the maximum trigger angle promotion strategy is allowed to be started based on the effective value of the alternating current voltage, determining whether the effective value of the alternating current voltage is within an operation range if the maximum trigger angle promotion strategy is allowed to be started, and starting the maximum trigger angle promotion strategy if the effective value of the alternating current voltage is within the operation range, so as to perform optimization control on the high-voltage direct-current system. The application promotes the active power injected into an alternating current system by the CLCC, reduces the reactive power consumed by a converter valve, speeds up the recovery of the alternating current voltage of the system, and improves the recovery characteristics of the alternating current power grid.

Description

Technical Field

[0001] This invention relates to the field of power system technology, and more specifically, to an optimized control method and system suitable for CLCC high-voltage DC systems. Background Technology

[0002] High-voltage direct current (HVDC) transmission technology based on line commutated converters (LCCs) is mature, reliable, has a large transmission capacity, and low losses, and has been widely used in long-distance power transmission, inter-regional power grid interconnection, and intra-provincial power sharing. However, conventional DC transmission lacks self-commutation capability and is prone to commutation failure during grid faults, leading to increased DC current, shortened converter valve life, and reduced transmitted power. With the increase in DC capacity and the dense feeding of multiple DC lines, commutation failure seriously threatens the safe and stable operation of DC equipment and the AC grid.

[0003] Domestic and foreign scholars have conducted extensive research on commutation failure suppression technology, which is mainly divided into two categories: optimized control strategy and improved topology. However, optimized control strategy can only reduce the risk of commutation failure, but cannot completely avoid commutation failure. In terms of improving topology, an existing technology based on a hybrid connection of fully controlled IGBTs and semi-controlled thyristors, the controllable line commutated converter (CLCC), completely avoids commutation failure from the topology perspective, and retains the advantages of low operating loss and low cost of LCC, which has broad prospects for engineering application.

[0004] Since its inception, CLCC-based high-voltage direct current (HVDC) transmission technology has rapidly gained widespread attention both domestically and internationally, and has been successfully applied to the Nanqiao converter station at the receiving end of the Ge-Nan DC transmission line. However, CLCC currently still employs traditional conventional DC control strategies, and there is an urgent need to further leverage the advantages of CLCC's controllable commutation, improve CLCC's fault response performance, and enhance the recovery speed of AC grid voltage. Summary of the Invention

[0005] To address the above problems, this invention proposes an optimized control method suitable for CLCC high-voltage DC systems, comprising:

[0006] Determine the topology and control strategy of the high-voltage direct current system's transmitting and receiving ends, and based on the topology and control strategy, determine whether the inverter-side converter station of the high-voltage direct current system enters the CLCC working mode;

[0007] If the CLCC working mode is entered, the effective value of the AC voltage of the converter bus of the high voltage DC system is detected in real time, and based on the effective value of the AC voltage, it is determined whether the maximum firing angle enhancement strategy is allowed to be started.

[0008] If permitted, determine whether the effective value of the AC voltage is within the operating range. If so, activate the maximum firing angle boosting strategy to optimize the control of the high-voltage DC system.

[0009] Optionally, based on the aforementioned topology and control strategy, determining whether the inverter-side converter station of the high-voltage direct current system enters CLCC operating mode includes:

[0010] If the CLCC enable signal is 0 or the inverter-side firing angle is less than the minimum firing angle α min If so, the inverter-side converter station is determined to be in LCC operating mode;

[0011] If the CLCC enable signal is 1 and the inverter-side firing angle is greater than or equal to the minimum firing angle α... min Then the inverter-side converter station operates in CLCC mode.

[0012] Optionally, based on the effective voltage value, determining whether to allow the maximum firing angle enhancement strategy to be activated includes:

[0013] If the AC voltage is greater than or equal to the maximum effective value of the AC voltage V acmax If the fault is found, it is determined that no fault has occurred in the high-voltage DC system, and the maximum firing angle enhancement strategy is not activated.

[0014] If the AC voltage is less than the maximum effective value of the AC voltage V acmax And greater than or equal to the minimum effective value of AC voltage V acmin If the fault occurs, the high-voltage DC system is determined to be faulty, and the maximum firing angle enhancement strategy is activated.

[0015] If the AC voltage is less than the minimum effective value of the AC voltage V acmin If the AC voltage of the CLCC converter bus is too low, the maximum firing angle boosting strategy will not be activated.

[0016] Optionally, the maximum firing angle enhancement strategy is activated to optimize the control of the high-voltage DC system, including:

[0017] The AC voltage error is calculated using the following formula:

[0018] ΔV ac =V ac -V acmax

[0019] The maximum trigger angle lift angle is calculated using the following formula:

[0020] Δα max =kΔV ac

[0021] Increase the trigger angle based on the maximum trigger angle.

[0022] Where, ΔV ac For AC voltage error, V ac AC voltage RMS value, V acmax The maximum effective value of AC voltage, Δα max The maximum trigger angle is increased by an angle, and k is a proportional coefficient.

[0023] Optionally, the method also includes:

[0024] The maximum trigger angle is increased by calculating the running time of the strategy to control the energy absorbed by the surge arrester to prevent it from exceeding the limit.

[0025] Furthermore, this invention also proposes an optimized control system suitable for CLCC high-voltage DC systems, comprising:

[0026] The first judgment module is used to determine the topology and control strategy of the high voltage DC system's sending and receiving ends, and based on the topology and control strategy, determine whether the inverter-side converter station of the high voltage DC system enters the CLCC working mode.

[0027] The second judgment module is used to detect the effective value of AC voltage of the converter bus of the high voltage DC system in real time after entering the CLCC working mode, and determine whether the maximum firing angle enhancement strategy is allowed to be started based on the effective value of AC voltage.

[0028] The optimization module is used to determine whether the effective value of the AC voltage is within the operating range after the maximum firing angle enhancement strategy is started. If so, the maximum firing angle enhancement strategy is started to optimize the control of the high voltage DC system.

[0029] Optionally, based on the aforementioned topology and control strategy, determining whether the inverter-side converter station of the high-voltage direct current system enters CLCC operating mode includes:

[0030] If the CLCC enable signal is 0 or the inverter-side firing angle is less than the minimum firing angle α min If so, the inverter-side converter station is determined to be in LCC operating mode;

[0031] If the CLCC enable signal is 1 and the inverter-side firing angle is greater than or equal to the minimum firing angle α... min Then the inverter-side converter station operates in CLCC mode.

[0032] Optionally, based on the effective voltage value, determining whether to allow the maximum firing angle enhancement strategy to be activated includes:

[0033] If the AC voltage is greater than or equal to the maximum effective value of the AC voltage V acmax If the fault is found, it is determined that no fault has occurred in the high-voltage DC system, and the maximum firing angle enhancement strategy is not activated.

[0034] If the AC voltage is less than the maximum effective value of the AC voltage V acmax And greater than or equal to the minimum effective value of AC voltage V acmin If the fault occurs, the high-voltage DC system is determined to be faulty, and the maximum firing angle enhancement strategy is activated.

[0035] If the AC voltage is less than the minimum effective value of the AC voltage V acmin If the AC voltage of the CLCC converter bus is too low, the maximum firing angle boosting strategy will not be activated.

[0036] Optionally, the maximum firing angle enhancement strategy is activated to optimize the control of the high-voltage DC system, including:

[0037] The AC voltage error is calculated using the following formula:

[0038] ΔV ac =V ac -V acmax

[0039] The maximum trigger angle lift angle is calculated using the following formula:

[0040] Δα max =kΔV ac

[0041] Increase the trigger angle based on the maximum trigger angle.

[0042] Where, ΔV ac For AC voltage error, V ac AC voltage RMS value, V acmax The maximum effective value of AC voltage, Δα max The maximum trigger angle is increased by an angle, and k is a proportional coefficient.

[0043] Optionally, the optimization module is also used for:

[0044] The maximum trigger angle is increased by calculating the running time of the strategy to control the energy absorbed by the surge arrester to prevent it from exceeding the limit.

[0045] In another aspect, the present invention also provides a computing device, comprising: one or more processors;

[0046] A processor is used to execute one or more programs;

[0047] When the one or more programs are executed by the one or more processors, the method described above is implemented.

[0048] In another aspect, the present invention also provides a computer-readable storage medium having a computer program stored thereon, which, when executed, implements the method described above.

[0049] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0050] This invention proposes an optimized control method for CLCC (Clear-Cooled Cylinder Capacitor) high-voltage direct current (HVDC) systems, comprising: determining the topology and control strategy of the HVDC system's sending and receiving ends; based on the topology and control strategy, determining whether the inverter-side converter station of the HVDC system has entered CLCC operating mode; if it has entered CLCC operating mode, then real-time monitoring of the effective value of the AC voltage of the HVDC system's converter bus; based on the effective value of the AC voltage, determining whether the maximum firing angle enhancement strategy is allowed; if allowed, determining whether the effective value of the AC voltage is within the operating range; if so, then activating the maximum firing angle enhancement strategy to optimize the control of the HVDC system. This invention increases the active power injected by the CLCC into the AC system and reduces the reactive power consumed by the converter valve, accelerates the recovery of the system's AC voltage, and improves the recovery characteristics of the AC power grid. Attached Figure Description

[0051] Figure 1 This is a flowchart of the method of the present invention;

[0052] Figure 2 This is a flowchart of an example of the method of the present invention;

[0053] Figure 3 This is a topology diagram of a CLCC-based high-voltage direct current transmission system as an example of the method of this invention;

[0054] Figure 4 This is a topology diagram of the CLCC in the method example of the present invention;

[0055] Figure 5 This is a diagram illustrating the maximum trigger angle enhancement strategy for a method example of the present invention.

[0056] Figure 6 The high-voltage DC system control strategy diagram for CLCC provided by this invention;

[0057] Figure 7 (af) is a comparison diagram of the response waveforms of CLCC before and after optimization under a three-phase fault at the remote end of the receiving-end power grid in the case of the method of the present invention.

[0058] Figure 8 (af) is a comparison diagram of the response waveforms of CLCC before and after optimization under a near-end three-phase fault in the receiving-end power grid in the case of the method of the present invention.

[0059] Figure 9 This is a structural diagram of the system of the present invention. Detailed Implementation

[0060] Exemplary embodiments of the invention will now be described with reference to the accompanying drawings. However, the invention may be embodied in many different forms and is not limited to the embodiments described herein. These embodiments are provided to fully and completely disclose the invention and to fully convey its scope to those skilled in the art. The terminology used in the exemplary embodiments illustrated in the drawings is not intended to limit the invention. In the drawings, the same units / elements are referred to by the same reference numerals.

[0061] Unless otherwise stated, the terms used herein (including technical terms) have their common meaning as understood by one of ordinary skill in the art. Furthermore, it is understood that terms defined in commonly used dictionaries should be understood to have a meaning consistent with the context of their relevant field, and not to be interpreted as having an idealized or overly formal meaning.

[0062] Example 1:

[0063] This invention proposes an optimized control method suitable for CLCC high-voltage DC systems, such as... Figure 1 As shown, it includes:

[0064] Step 1: Determine the topology and control strategy of the high-voltage direct current system's transmitting and receiving ends. Based on the topology and control strategy, determine whether the inverter-side converter station of the high-voltage direct current system enters the CLCC working mode.

[0065] Step 2: If the CLCC working mode is entered, the effective value of the AC voltage of the converter bus of the high voltage DC system is detected in real time. Based on the effective value of the AC voltage, it is determined whether the maximum firing angle enhancement strategy is allowed to be started.

[0066] Step 3: If allowed, determine whether the effective value of the AC voltage is within the operating range. If so, activate the maximum firing angle boosting strategy to optimize the control of the high-voltage DC system.

[0067] Specifically, determining whether the inverter-side converter station of the high-voltage DC system enters CLCC operating mode based on the aforementioned topology and control strategy includes:

[0068] If the CLCC enable signal is 0 or the inverter-side firing angle is less than the minimum firing angle α min If so, the inverter-side converter station is determined to be in LCC operating mode;

[0069] If the CLCC enable signal is 1 and the inverter-side firing angle is greater than or equal to the minimum firing angle α... min Then the inverter-side converter station operates in CLCC mode.

[0070] The determination of whether to allow the maximum firing angle boosting strategy to be activated based on the effective voltage value includes:

[0071] If the AC voltage is greater than or equal to the maximum effective value of the AC voltage V acmax If the fault is found, it is determined that no fault has occurred in the high-voltage DC system, and the maximum firing angle enhancement strategy is not activated.

[0072] If the AC voltage is less than the maximum effective value of the AC voltage V acmax And greater than or equal to the minimum effective value of AC voltage V acmin If the fault occurs, the high-voltage DC system is determined to be faulty, and the maximum firing angle enhancement strategy is activated.

[0073] If the AC voltage is less than the minimum effective value of the AC voltage V acmin If the AC voltage of the CLCC converter bus is too low, the maximum firing angle boosting strategy will not be activated.

[0074] The maximum firing angle enhancement strategy is activated to optimize the control of the high-voltage DC system, including:

[0075] The AC voltage error is calculated using the following formula:

[0076] ΔV ac =V ac -V acmax

[0077] The maximum trigger angle lift angle is calculated using the following formula:

[0078] Δα max =kΔV ac

[0079] Increase the trigger angle based on the maximum trigger angle.

[0080] Where, ΔV ac For AC voltage error, V ac AC voltage RMS value, V acmax The maximum effective value of AC voltage, Δα max The maximum trigger angle is increased by an angle, and k is a proportional coefficient.

[0081] The methods also include:

[0082] The maximum trigger angle is increased by calculating the running time of the strategy to control the energy absorbed by the surge arrester to prevent it from exceeding the limit.

[0083] The invention will be further illustrated below with specific examples:

[0084] like Figure 2 As shown, the implementation steps for a specific case include:

[0085] (1) Study the topology and control strategy of the converter stations on the rectifier side and inverter side of the high voltage DC system, and determine whether the converter station on the inverter side has entered the CLCC working mode.

[0086] (2) Real-time detection of the effective value of AC voltage on the converter bus to determine whether the maximum firing angle boosting strategy is allowed to start;

[0087] (3) If the effective value of AC voltage is within the operating range, the maximum firing angle enhancement strategy is activated to increase the maximum firing angle during the fault, thereby increasing the active power of CLCC and reducing the reactive power consumption of the converter valve.

[0088] (4) Based on whether the maximum firing angle enhancement strategy is activated, the running time of the maximum firing angle enhancement strategy is calculated to avoid the surge arrester absorbing energy beyond the limit.

[0089] Step (1) includes:

[0090] Step 101: Study the topology and control strategy of the converter stations at the sending and receiving ends of the high-voltage direct current (HVDC) system. Conventional HVDC uses a true bipolar connection, eliminating the risk of commutation failure on the rectifier side, and thus retains the LCC topology and control strategy. The inverter side adopts a CLCC topology, which adds a main fully controlled valve V12, an auxiliary fully controlled valve V13, and a low-current thyristor valve V14 to the traditional high-voltage thyristor converter valve V11. Thyristors and IGBTs are connected in parallel with RC damping and RCD damping circuits respectively to achieve dynamic voltage equalization. In steady state, the rectifier-side LCC operates in constant DC current control mode, while the inverter-side CLCC operates in constant DC voltage control mode.

[0091] Step 102: Determine whether the inverter-side converter station is in CLCC operating mode.

[0092] If the CLCC enable signal is 0 or the inverter-side firing angle is less than α min If so, the inverter-side converter station is determined to be in LCC operating mode.

[0093] If the CLCC enable signal is 1 and the inverter-side firing angle is greater than or equal to α... min The inverter-side converter station operates in CLCC mode.

[0094] Step (2) includes:

[0095] The effective value of the AC voltage on the converter bus is monitored in real time, and the maximum firing angle boosting strategy is determined based on the magnitude of the effective AC voltage value.

[0096] If the AC voltage is greater than or equal to V acmax If no fault has occurred, the maximum trigger angle increase strategy will not be activated.

[0097] If the AC voltage is less than V acmaxAnd greater than or equal to V acmin If a fault occurs, the maximum trigger angle increase strategy will be activated.

[0098] If the AC voltage is less than V acmin If the AC voltage of the CLCC converter bus is too low, the maximum firing angle boosting strategy will not be activated.

[0099] Step (3) includes:

[0100] Step 301: Detect the effective value V of the three-phase AC voltage of the CLCC converter bus. ac The AC voltage error ΔV is calculated based on Equation 1. ac :

[0101] ΔV ac =V ac -V acmax (1)

[0102] Step 302: Calculate the maximum trigger angle lift angle Δα using Equation 2. max In the formula, k represents the AC voltage-firing angle proportionality coefficient.

[0103] Δα max =kΔV ac (2)

[0104] Step 303: Calculate the maximum trigger angle increase angle Δα max The firing angle command value α of the maximum firing angle control output max0 Add them together.

[0105] α max =kΔα max +α max0 (3)

[0106] Step 304: After increasing the maximum firing angle α, the CLCC will output a larger firing angle command value during grid faults at the receiving end, reducing the CLCC's overshoot firing angle β, maintaining a higher level of DC voltage, and also outputting a higher level of active power. Furthermore, increasing the CLCC's firing angle, as shown in Equation 4, will decrease the CLCC's leading firing angle, i.e., increase the CLCC's equivalent power factor angle cosφ. I) (As shown in Equation 5), thereby reducing the reactive power Q consumed by the converter valve. CLCC (As shown in Equation 6). Considering the reactive power QSI exchanged between the CLCC converter station and the AC system, as shown in Equation 7, Q CLCC After the reduction, the converter station will rely on AC filters to inject more reactive power into the AC system, thereby promoting the improvement of AC voltage.

[0107] β=180°-α (4)

[0108]

[0109]

[0110] Q SI =Q CLCC -Q FLTI (7)

[0111] In the formula, U di0 X represents the no-load DC voltage on the inverter side, and I represents the commutation reactance. dc P represents direct current. dc Q represents DC power. FLTI This represents the reactive power output of the AC filter.

[0112] Step (4) includes:

[0113] Based on whether the maximum firing angle enhancement strategy is activated, the running time of the maximum firing angle enhancement strategy is calculated to prevent the surge arrester from absorbing energy exceeding the limit.

[0114] If the maximum trigger angle boosting strategy is not activated, the timer will not be used.

[0115] If the maximum trigger angle boosting strategy is activated, calculate the duration of the maximum trigger angle boosting strategy. If the duration of the maximum trigger angle boosting strategy exceeds the maximum allowed time t... max Then the maximum trigger angle boosting strategy will be disabled.

[0116] The following uses a specific system as an example to verify the invention. The process is as follows:

[0117] (1) Study the topology and control strategy of the converter stations on the rectifier side and inverter side of the high voltage DC system, and determine whether the converter station on the inverter side has entered the CLCC working mode.

[0118] 1) The topology of the CLCC-based high-voltage direct current transmission system is shown in the attached figure. Figure 3 As shown, the dual-ended conventional DC circuit uses a true bipolar connection. The rectifier-side converter station has no risk of commutation failure and still uses the LCC topology and control strategy. The inverter side uses a CLCC topology, completely avoiding commutation failure from a topological perspective. The six-pulse CLCC topology is shown in the attached figure. Figure 4 As shown, based on the traditional high-voltage thyristor converter valve V11, the CLCC adds a main fully control valve V12, an auxiliary fully control valve V13, and a low-current thyristor valve V14. The thyristors and IGBTs are connected in parallel with RC damping and RCD damping circuits respectively to achieve dynamic voltage equalization. Different specifications of metal oxide surge arresters are connected in parallel with power electronic devices and bridge arms to prevent overvoltage damage to the equipment.

[0119] 2) Determine whether the inverter-side converter station is in CLCC working mode.

[0120] If the CLCC enable signal is 0 or the inverter-side firing angle is less than α min If so, the inverter-side converter station is determined to be in LCC operating mode.

[0121] If the CLCC enable signal is 1 and the inverter-side firing angle is greater than or equal to α... min The inverter-side converter station operates in CLCC mode.

[0122] (2) Real-time detection of the effective value of AC voltage on the converter bus to determine whether the maximum firing angle boosting strategy is allowed to start;

[0123] 1) If the AC voltage is greater than or equal to V acmax If no fault has occurred, the maximum trigger angle increase strategy will not be activated.

[0124] 2) If the AC voltage is less than V acmax And greater than or equal to V acmin If a fault occurs, the maximum trigger angle increase strategy will be activated.

[0125] 3) If the AC voltage is less than V acmin If the AC voltage of the CLCC converter bus is too low, the maximum firing angle boosting strategy will not be activated.

[0126] (3) If the effective value of the AC voltage is within the operating range, the maximum firing angle enhancement strategy is activated to increase the maximum firing angle during the fault period, thereby increasing the active power of the CLCC while reducing the reactive power consumption of the converter valve; the maximum firing angle enhancement strategy provided by this invention is attached. Figure 5 As shown.

[0127] 1) Detect the effective value V of the three-phase AC voltage of the CLCC converter bus. ac The AC voltage error ΔV is calculated based on Equation 1. ac :

[0128] 2) Calculate the maximum trigger angle lift angle Δα using Equation 2. max In the formula, k represents the AC voltage-firing angle proportionality coefficient.

[0129] 3) Calculate the maximum trigger angle lift angle Δα max The firing angle command value α of the maximum firing angle control output max0 Add. The control structure of CLCC is shown in the attached figure. Figure 6 As shown, the maximum firing angle command value output is used as the upper limit of the constant DC voltage control, and together with the firing angle command value output by the constant DC voltage regulator, it affects the upper limit of the current control amplifier.

[0130] 4) After increasing the maximum firing angle, the CLCC will output a larger firing angle command value during grid faults at the receiving end, reducing the overdue firing angle β of the CLCC output, maintaining a higher level of DC voltage, and also outputting a higher level of active power. Furthermore, increasing the firing angle of the CLCC, as shown in equations 4 to 6, will increase the equivalent power factor angle of the CLCC, thereby reducing the reactive power consumed by the converter valve. The reactive power exchanged between the CLCC converter station and the AC system is shown in equation 7, Q. CLCC After the reduction, the converter station will rely on AC filters to inject more reactive power into the AC system, thereby promoting the improvement of AC voltage.

[0131] (4) Based on whether the maximum firing angle enhancement strategy is activated, the running time of the maximum firing angle enhancement strategy is calculated to avoid the surge arrester absorbing energy beyond the limit.

[0132] The following is an example:

[0133] In the PSMode l (Power System Mode l) electromagnetic transient simulation software, an electromechanical transient model of the AC power grid at both the sending and receiving ends was built, and the simulation scale is shown in Table 1. A CLCC Genan HVDC electromagnetic transient model was also built, and the parameters are shown in Table 2.

[0134] Table 1

[0135]

[0136] Table 2

[0137]

[0138] A CLCC control method based on maximum firing angle enhancement was adopted, and the control parameters are shown in Appendix Table 3. Three-phase short-circuit faults in the near and far zones of the receiving-end AC power grid were simulated respectively, and the differences in CLCC fault characteristics before and after the adoption of the optimized control method were compared.

[0139] Table 3

[0140]

[0141] Appendix Figure 7 (af) is a comparison of the characteristics of CLCC before and after the implementation of optimized control under a near-end three-phase short-circuit fault. (See attached image.) Figure 8(af) compares the characteristics of the CLCC before and after optimized control under a remote three-phase short-circuit fault. The red curve is the response waveform of the CLCC before optimization, and the blue curve is the response waveform of the CLCC after optimization. After adopting the maximum firing angle boosting control method, the firing angle command on the inverter side is increased by 6° to 10°. After disconnecting the faulty line, the DC power boosting speed of the receiving-end converter valve is faster and the energy loss of the receiving-end AC system is smaller under the maximum firing angle boosting control. At the same time, the reactive power consumed by the receiving-end converter valve is smaller under the maximum firing angle boosting control, and the AC filter of the converter station injects more reactive power into the AC system, significantly improving the recovery speed of the grid AC voltage. Appendix Table 4 shows the energy absorption of the CLCC surge arrester. The surge arrester absorbs more energy before and after adopting the maximum firing angle boosting control. Therefore, the energy absorption of the surge arrester must be considered when adopting the maximum firing angle boosting control to avoid the surge arrester energy exceeding the limit.

[0142] Table 4

[0143]

[0144] Example 2:

[0145] This invention also proposes an optimized control system 200 suitable for CLCC high-voltage DC systems, such as... Figure 9 As shown, it includes:

[0146] The first judgment module 201 is used to determine the topology and control strategy of the high voltage DC system's sending and receiving ends, and based on the topology and control strategy, determine whether the inverter-side converter station of the high voltage DC system has entered the CLCC working mode.

[0147] The second judgment module 202 is used to detect the effective value of the AC voltage of the converter bus of the high voltage DC system in real time after entering the CLCC working mode, and determine whether the maximum firing angle enhancement strategy is allowed to be started based on the effective value of the AC voltage.

[0148] The optimization module 203 is used to determine whether the effective value of the AC voltage is within the operating range after the maximum firing angle enhancement strategy is started. If so, the maximum firing angle enhancement strategy is started to optimize the control of the high voltage DC system.

[0149] Specifically, determining whether the inverter-side converter station of the high-voltage DC system enters CLCC operating mode based on the aforementioned topology and control strategy includes:

[0150] If the CLCC enable signal is 0 or the inverter-side firing angle is less than the minimum firing angle α min If so, the inverter-side converter station is determined to be in LCC operating mode;

[0151] If the CLCC enable signal is 1 and the inverter-side firing angle is greater than or equal to the minimum firing angle α... min Then the inverter-side converter station operates in CLCC mode.

[0152] The determination of whether to allow the maximum firing angle boosting strategy to be activated based on the effective voltage value includes:

[0153] If the AC voltage is greater than or equal to the maximum effective value of the AC voltage V acmax If the fault is found, it is determined that no fault has occurred in the high-voltage DC system, and the maximum firing angle enhancement strategy is not activated.

[0154] If the AC voltage is less than the maximum effective value of the AC voltage V acmax And greater than or equal to the minimum effective value of AC voltage V acmin If the fault occurs, the high-voltage DC system is determined to be faulty, and the maximum firing angle enhancement strategy is activated.

[0155] If the AC voltage is less than the minimum effective value of the AC voltage V acmin If the AC voltage of the CLCC converter bus is too low, the maximum firing angle boosting strategy will not be activated.

[0156] The maximum firing angle enhancement strategy is activated to optimize the control of the high-voltage DC system, including:

[0157] The AC voltage error is calculated using the following formula:

[0158] ΔV ac =V ac -V acmax

[0159] The maximum trigger angle lift angle is calculated using the following formula:

[0160] Δα max =kΔV ac

[0161] Increase the trigger angle based on the maximum trigger angle.

[0162] Where, ΔV ac For AC voltage error, V ac AC voltage RMS value, V acmax The maximum effective value of AC voltage, Δα max The maximum trigger angle is increased by an angle, and k is a proportional coefficient.

[0163] The optimization module 203 is also used for:

[0164] The maximum trigger angle is increased by calculating the running time of the strategy to control the energy absorbed by the surge arrester to prevent it from exceeding the limit.

[0165] This invention increases the active power injected into the AC system by the CLCC and reduces the reactive power consumed by the converter valve, thereby accelerating the recovery of the AC voltage in the system and improving the recovery characteristics of the AC power grid.

[0166] Example 3:

[0167] Based on the same inventive concept, this invention also provides a computer device, which includes a processor and a memory. The memory stores a computer program, which includes program instructions. The processor executes 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 (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. It is the computing and control core of the terminal, suitable for implementing one or more instructions, specifically suitable for loading and executing one or more instructions in the computer storage medium to implement corresponding method flows or corresponding functions, thereby implementing the steps of the methods in the above embodiments.

[0168] Example 4:

[0169] Based on the same inventive concept, this invention also provides a storage medium, specifically a computer-readable storage medium (Memory), which is a memory device in a computer device used to store programs and data. It is understood that the computer-readable storage medium here can include both the built-in storage medium in the computer device and extended storage media supported by the computer device. The computer-readable storage medium provides storage space that stores the terminal's operating system. Furthermore, this storage space also stores one or more instructions suitable for loading and execution by a processor. These instructions can be one or more computer programs (including program code). It should be noted that the computer-readable storage medium here can be high-speed RAM or non-volatile memory, such as at least one disk storage device. The processor can load and execute one or more instructions stored in the computer-readable storage medium to implement the steps of the method in the above embodiments.

[0170] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can 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. The solutions in the embodiments of the present invention can be implemented using various computer languages, such as the object-oriented programming language Java and the interpreted scripting language JavaScript.

[0171] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0172] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0173] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0174] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0175] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. An optimized control method suitable for CLCC high-voltage DC systems, characterized in that, The optimized control method includes: Determine the topology and control strategy of the high-voltage direct current system's transmitting and receiving ends, and based on the topology and control strategy, determine whether the inverter-side converter station of the high-voltage direct current system enters the CLCC working mode; If the CLCC working mode is entered, the effective value of the AC voltage of the converter bus of the high voltage DC system is detected in real time, and based on the effective value of the AC voltage, it is determined whether the maximum firing angle enhancement strategy is allowed to be started. If permitted, determine whether the effective value of the AC voltage is within the operating range. If so, activate the maximum firing angle boosting strategy to optimize the control of the high-voltage DC system. The step of determining whether the inverter-side converter station of the high-voltage DC system enters CLCC operating mode based on the topology and control strategy includes: If the CLCC enable signal is 0 or the inverter-side firing angle is less than the minimum firing angle. α min If so, the inverter-side converter station is determined to be in LCC operating mode; If the CLCC enable signal is 1 and the inverter-side firing angle is greater than or equal to the minimum firing angle. α min Then the inverter-side converter station operates in CLCC mode; The step of determining whether to allow the maximum firing angle boosting strategy to be activated based on the effective voltage value includes: If the AC voltage is greater than or equal to the maximum effective value of the AC voltage V acmax If the fault is found, it is determined that no fault has occurred in the high-voltage DC system, and the maximum firing angle enhancement strategy is not activated. If the AC voltage is less than the maximum effective value of the AC voltage V acmax And greater than or equal to the minimum effective value of AC voltage V acmin If the fault occurs, the high-voltage DC system is determined to be faulty, and the maximum firing angle enhancement strategy is activated. If the AC voltage is less than the minimum effective value of the AC voltage V acmin If the AC voltage of the CLCC converter bus is too low, the maximum firing angle boosting strategy will not be activated. The activation of the maximum firing angle enhancement strategy for optimized control of the high-voltage DC system includes: The AC voltage error is calculated using the following formula: The maximum trigger angle lift angle is calculated using the following formula: Increase the trigger angle based on the maximum trigger angle. in, For AC voltage error, AC voltage RMS value The maximum effective value of AC voltage, Increase the angle and maximum trigger angle k This is the proportionality coefficient.

2. The optimized control method according to claim 1, characterized in that, The method further includes: The maximum trigger angle is increased by calculating the running time of the strategy to control the energy absorbed by the surge arrester to prevent it from exceeding the limit.

3. An optimized control system suitable for CLCC high-voltage DC systems, characterized in that, The optimized control system includes: The first judgment module is used to determine the topology and control strategy of the high voltage DC system's sending and receiving ends, and based on the topology and control strategy, determine whether the inverter-side converter station of the high voltage DC system enters the CLCC working mode. The second judgment module is used to detect the effective value of AC voltage of the converter bus of the high voltage DC system in real time after entering the CLCC working mode, and determine whether the maximum firing angle enhancement strategy is allowed to be started based on the effective value of AC voltage. The optimization module is used to determine whether the effective value of the AC voltage is within the operating range after the maximum firing angle enhancement strategy is started. If so, the maximum firing angle enhancement strategy is started to optimize the control of the high voltage DC system. The step of determining whether the inverter-side converter station of the high-voltage DC system enters CLCC operating mode based on the topology and control strategy includes: If the CLCC enable signal is 0 or the inverter-side firing angle is less than the minimum firing angle. α min If so, the inverter-side converter station is determined to be in LCC operating mode; If the CLCC enable signal is 1 and the inverter-side firing angle is greater than or equal to the minimum firing angle. α min Then the inverter-side converter station operates in CLCC mode; The step of determining whether to allow the maximum firing angle boosting strategy to be activated based on the effective voltage value includes: If the AC voltage is greater than or equal to the maximum effective value of the AC voltage V acmax If the fault is found, it is determined that no fault has occurred in the high-voltage DC system, and the maximum firing angle enhancement strategy is not activated. If the AC voltage is less than the maximum effective value of the AC voltage V acmax And greater than or equal to the minimum effective value of AC voltage V acmin If the fault occurs, the high-voltage DC system is determined to be faulty, and the maximum firing angle enhancement strategy is activated. If the AC voltage is less than the minimum effective value of the AC voltage V acmin If the AC voltage of the CLCC converter bus is too low, the maximum firing angle boosting strategy will not be activated. The activation of the maximum firing angle enhancement strategy for optimized control of the high-voltage DC system includes: The AC voltage error is calculated using the following formula: The maximum trigger angle lift angle is calculated using the following formula: Increase the trigger angle based on the maximum trigger angle. in, For AC voltage error, AC voltage RMS value The maximum effective value of AC voltage, Increase the angle and maximum trigger angle k This is the proportionality coefficient.

4. The optimized control system according to claim 3, characterized in that, The optimization module is also used for: The maximum trigger angle is increased by calculating the running time of the strategy to control the energy absorbed by the surge arrester to prevent it from exceeding the limit.

5. A computer device, characterized in that, include: One or more processors; A processor is used to execute one or more programs; When the one or more programs are executed by the one or more processors, the method described in any one of claims 1-2 is implemented.

6. A computer-readable storage medium, characterized in that, It contains a computer program, which, when executed, implements the method as described in any one of claims 1-2.

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