Converter valve assembly MOV energy out-of-limit active turn-off method, converter valve controller and converter valve

Abstract

The invention belongs to the technical field of high-voltage direct-current power transmission, and particularly relates to a converter valve assembly MOV energy out-of-limit active turn-off method, a converter valve controller and a converter valve. After a signal of actively turning off the converter valve is detected, the residual effective absorbable energy of the MOV is calculated in real time: if the residual effective absorbable energy is very small, the active turn-off function of the converter valve is forbidden, the MOV is in an absorption capacity self-recovery state, and after the residual effective absorbable energy of the MOV is recovered to be relatively large, the active turn-off function of the converter valve is unlocked; if the residual effective absorbable energy is small, the converter valve is controlled to reduce direct current operation; and if the remaining effective absorbable energy can be still available, the MOV is in an absorption capacity self-recovery state. Different processing modes are adopted for the component MOV under various different conditions, the overheating protection capability of the component MOV can be improved, safe and reliable operation of equipment is guaranteed, and the safe and stable performance of a power grid system is improved.

Description

Technical Field

[0001] This invention belongs to the field of high voltage direct current transmission technology, specifically relating to a method for active shutdown of MOV energy exceeding limits in a converter valve assembly, a converter valve controller, and a converter valve. Background Technology

[0002] High-voltage direct current (HVDC) transmission technology is a long-distance, high-capacity power transmission technology with significant technical and economic advantages. However, conventional thyristor commutation technology has always suffered from the intractable problem of commutation failure, which seriously threatens the safe and stable operation of HVDC multi-point grids. Commutation technology based on reverse-resistance type IGCT devices can effectively solve the inherent commutation failure problem of conventional HVDC transmission systems, reduce the power impact on AC systems, and improve the safe and stable operation capability of large power grids.

[0003] IGCT converter valves require a large number of turn-off IGCT devices connected in series. To limit overvoltage during active IGCT turn-off and to achieve dynamic and static voltage equalization among the series devices, the IGCT converter valve series structure is also equipped with an RC damping circuit and an MOV (Mechanical Oxide Valves) energy absorption circuit. Since the commutation process after active turn-off involves current flow through the MOVs, if a short circuit or device failure occurs in the MOV, causing it to carry a large current for an extended period, the accumulated energy in the MOVs could lead to overheating and pressure release, posing a significant risk to the safe and reliable operation of the converter valve. Summary of the Invention

[0004] The purpose of this invention is to provide a method for active shutdown of a converter valve assembly (MOV) when its energy exceeds the limit, a converter valve controller, and a converter valve, in order to solve the problem that if the MOV assembly fails during the commutation process after active shutdown in the prior art, it will pose a risk to the safe and reliable operation of the converter valve.

[0005] To address the aforementioned technical problems, this invention provides a technical solution for an active shutdown method for MOV (Multi-Active Valves) energy over-limit operation in converter valve assemblies, as detailed below:

[0006] A method for active shutdown of MOV (Multi-Vehicle Energy Limit) converter assembly, comprising:

[0007] After detecting the active shut-off converter valve signal, the remaining effective absorbable energy of the MOV component is calculated in real time:

[0008] If the remaining effective absorbable energy is less than or equal to the minimum absorbable energy design value, the active shut-off function of the converter valve is disabled, and the MOV module is in a self-recovery state of absorption capacity. The active shut-off function of the converter valve is unlocked after the remaining effective absorbable energy of the MOV module recovers to greater than or equal to the maximum absorbable energy design value.

[0009] If the remaining effective absorbable energy is greater than the minimum absorbable energy design value and less than or equal to the current reduction setting value, then control the converter valve to reduce the DC current.

[0010] If the remaining effective absorbable energy is greater than the reduced current setting value and less than or equal to the maximum absorbable energy design value, the MOV component is in a self-recovery state of absorption capacity.

[0011] The minimum absorbable energy design value is less than the reduced current setting value, and the reduced current setting value is less than the maximum absorbable energy design value.

[0012] The beneficial effects of the above technical solution are as follows: This invention monitors the status of the component MOV in real time and adopts different control methods according to the MOV status to ensure that the component MOV will not fail. Specific control methods include: when the remaining effective absorbable energy of the component MOV is very low, the active shutdown function of the converter valve is prohibited to prevent the component MOV from continuing to participate in current flow after active shutdown, which could easily lead to short circuits or device failure to turn on. The active shutdown function is only unlocked after the remaining effective absorbable energy of the component MOV recovers to a larger value, ensuring that the MOV has a greater capacity to absorb energy when the active shutdown function is unlocked; when the remaining effective absorbable energy of the component MOV is relatively low, the converter valve is controlled to reduce DC current operation to reduce fault current and overvoltage amplitude, reduce energy impact during faults, reduce the risk of MOV failure, and help the system maintain safe operation even when MOV capacity is limited, avoiding the amplification of faults due to protection failure; when the remaining effective absorbable energy of the component MOV is still sufficient, no action is needed, allowing the component MOV to be in a self-recovery state of absorption capacity. The above-mentioned scheme adopts different treatment methods for the MOV of the module under various conditions, which can improve the overheat protection capability of the MOV of the module, ensure the safe and reliable operation of the equipment, and enhance the safety and stability of the power grid system.

[0013] Furthermore, the reduced DC current is positively correlated with the remaining effective absorbable energy of the MOV component.

[0014] Furthermore, the reduced DC current shows a positive linear relationship with the remaining effective absorbable energy of the MOV component.

[0015] Furthermore, the formula for calculating the reduced DC current is:

[0016]

[0017] In the formula, I 设定 To reduce the DC current, E R E represents the remaining effective absorbable energy of the MOV component. L E is the minimum absorbable energy design value.M To reduce the current setting value.

[0018] Furthermore, the remaining effective absorbable energy of the MOV under the self-recovery state of the absorption capacity is:

[0019]

[0020] In the formula, E R E represents the remaining effective absorbable energy of the MOV in its real-time self-recovery state. R0 K represents the remaining effective absorbable energy of the MOV before it reaches a self-recovery state, and K represents the energy absorption capacity of the MOV unit under natural heat dissipation conditions. This refers to the time during which the absorption capacity is in a self-recovery state.

[0021] Furthermore, the remaining effective absorbable energy of the MOV module is the difference between the rated absorbable energy of the MOV module and the effective absorbed energy of the MOV module. The effective absorbed energy of the MOV module is:

[0022]

[0023] In the formula, E n U represents the effective absorbed energy of the MOV component, U represents the protection level of the IGCT converter valve arrester, and I represents the effective absorbed energy. n Let N be the arm current at the nth sampling time, T be the arm current sampling interval, and N be the ratio of the total time the MOV module is engaged to the current sampling interval T.

[0024] To address the aforementioned technical problems, the present invention also provides a technical solution for a converter valve controller, as detailed below:

[0025] A converter valve controller according to the present invention includes a processor, the processor executing a computer program to implement the steps of the following method:

[0026] After detecting the active shut-off converter valve signal, the remaining effective absorbable energy of the MOV component is calculated in real time:

[0027] If the remaining effective absorbable energy is less than or equal to the minimum absorbable energy design value, the active shut-off function of the converter valve is disabled, and the MOV module is in a self-recovery state of absorption capacity. The active shut-off function of the converter valve is unlocked after the remaining effective absorbable energy of the MOV module recovers to greater than or equal to the maximum absorbable energy design value.

[0028] If the remaining effective absorbable energy is greater than the minimum absorbable energy design value and less than or equal to the current reduction setting value, then control the converter valve to reduce the DC current.

[0029] If the remaining effective absorbable energy is greater than the reduced current setting value and less than or equal to the maximum absorbable energy design value, the MOV component is in a self-recovery state of absorption capacity.

[0030] The minimum absorbable energy design value is less than the reduced current setting value, and the reduced current setting value is less than the maximum absorbable energy design value.

[0031] The beneficial effects of the above technical solution are as follows: The converter valve controller of the present invention adopts a strategy that can ensure the safe operation of the MOV component and improve its overheat protection capability. Specifically, the strategy is to monitor the status of the MOV component in real time and adopt different control methods according to the MOV status to ensure that the MOV component will not fail. Specific control methods include: when the remaining effective absorbable energy of the MOV module is very low, the active shutdown function of the converter valve is prohibited to prevent the MOV module from continuing to participate in current flow after active shutdown, which could easily lead to short circuits or device failure to turn on. The active shutdown function is only unlocked after the remaining effective absorbable energy of the MOV module recovers to a larger value, ensuring that the MOV has sufficient energy absorption capacity when the active shutdown function is unlocked. When the remaining effective absorbable energy of the MOV module is relatively low, the converter valve is controlled to reduce DC current operation to reduce fault current and overvoltage amplitude, reduce energy impact during faults, reduce the risk of MOV failure, and help the system maintain safe operation even when MOV capacity is limited, avoiding escalation of faults due to protection failure. When the remaining effective absorbable energy of the MOV module is still sufficient, no action is needed, allowing the MOV module to remain in a self-recovery state. The above scheme employs different treatment methods for the MOV module under various conditions, which can improve the overheat protection capability of the MOV module, ensure the safe and reliable operation of the equipment, and enhance the safety and stability performance of the power grid system.

[0032] Furthermore, the reduced DC current is positively correlated with the remaining effective absorbable energy of the MOV component.

[0033] Furthermore, the reduced DC current shows a positive linear relationship with the remaining effective absorbable energy of the MOV component.

[0034] Furthermore, the formula for calculating the reduced DC current is:

[0035]

[0036] In the formula, I 设定 To reduce the DC current, E R E represents the remaining effective absorbable energy of the MOV component. L E is the minimum absorbable energy design value. M To reduce the current setting value.

[0037] Furthermore, the remaining effective absorbable energy of the MOV under the self-recovery state of the absorption capacity is:

[0038]

[0039] In the formula, E R E represents the remaining effective absorbable energy of the MOV in its real-time self-recovery state. R0 K represents the remaining effective absorbable energy of the MOV before it reaches a self-recovery state, and K represents the energy absorption capacity of the MOV unit under natural heat dissipation conditions. This refers to the time during which the absorption capacity is in a self-recovery state.

[0040] Furthermore, the remaining effective absorbable energy of the MOV module is the difference between the rated absorbable energy of the MOV module and the effective absorbed energy of the MOV module. The effective absorbed energy of the MOV module is:

[0041]

[0042] In the formula, E n U represents the effective absorbed energy of the MOV component, U represents the protection level of the IGCT converter valve arrester, and I represents the effective absorbed energy. n Let N be the arm current at the nth sampling time, T be the arm current sampling interval, and N be the ratio of the total time the MOV module is engaged to the current sampling interval T.

[0043] To solve the above-mentioned technical problems, the present invention also provides a technical solution for a converter valve, as follows:

[0044] A converter valve according to the present invention includes a converter valve body and a converter valve controller. The converter valve body includes an assembly MOV, and the converter valve controller includes a processor. The processor executes a computer program to implement the steps of the following method:

[0045] After detecting the active shut-off converter valve signal, the remaining effective absorbable energy of the MOV component is calculated in real time:

[0046] If the remaining effective absorbable energy is less than or equal to the minimum absorbable energy design value, the active shut-off function of the converter valve is disabled, and the MOV module is in a self-recovery state of absorption capacity. The active shut-off function of the converter valve is unlocked after the remaining effective absorbable energy of the MOV module recovers to greater than or equal to the maximum absorbable energy design value.

[0047] If the remaining effective absorbable energy is greater than the minimum absorbable energy design value and less than or equal to the current reduction setting value, then control the converter valve to reduce the DC current.

[0048] If the remaining effective absorbable energy is greater than the reduced current setting value and less than or equal to the maximum absorbable energy design value, the MOV component is in a self-recovery state of absorption capacity.

[0049] The minimum absorbable energy design value is less than the reduced current setting value, and the reduced current setting value is less than the maximum absorbable energy design value.

[0050] The beneficial effects of the above technical solution are as follows: In the converter valve of the present invention, the converter valve controller, when controlling the converter valve body, adopts an active shutdown strategy for the converter valve component MOV energy exceeding the limit to ensure the effective and reliable operation of the component MOV. Specifically, this strategy involves real-time monitoring of the state of the component MOV and adopting different control methods according to the MOV state to ensure that the component MOV does not malfunction. Specific control methods include: when the remaining effective absorbable energy of the MOV module is very low, the active shutdown function of the converter valve is prohibited to prevent the MOV module from continuing to participate in current flow after active shutdown, which could easily lead to short circuits or device failure to turn on. The active shutdown function is only unlocked after the remaining effective absorbable energy of the MOV module recovers to a larger value, ensuring that the MOV has sufficient energy absorption capacity when the active shutdown function is unlocked. When the remaining effective absorbable energy of the MOV module is relatively low, the converter valve is controlled to reduce DC current operation to reduce fault current and overvoltage amplitude, reduce energy impact during faults, reduce the risk of MOV failure, and help the system maintain safe operation even when MOV capacity is limited, avoiding escalation of faults due to protection failure. When the remaining effective absorbable energy of the MOV module is still sufficient, no action is needed, allowing the MOV module to remain in a self-recovery state. The above scheme employs different treatment methods for the MOV module under various conditions, which can improve the overheat protection capability of the MOV module, ensure the safe and reliable operation of the equipment, and enhance the safety and stability performance of the power grid system.

[0051] Furthermore, the reduced DC current is positively correlated with the remaining effective absorbable energy of the MOV component.

[0052] Furthermore, the reduced DC current shows a positive linear relationship with the remaining effective absorbable energy of the MOV component.

[0053] Furthermore, the formula for calculating the reduced DC current is:

[0054]

[0055] In the formula, I 设定 To reduce the DC current, E R E represents the remaining effective absorbable energy of the MOV component. L E is the minimum absorbable energy design value.M To reduce the current setting value.

[0056] Furthermore, the remaining effective absorbable energy of the MOV under the self-recovery state of the absorption capacity is:

[0057]

[0058] In the formula, E R E represents the remaining effective absorbable energy of the MOV in its real-time self-recovery state. R0 K represents the remaining effective absorbable energy of the MOV before it reaches a self-recovery state, and K represents the energy absorption capacity of the MOV unit under natural heat dissipation conditions. This refers to the time during which the absorption capacity is in a self-recovery state.

[0059] Furthermore, the remaining effective absorbable energy of the MOV module is the difference between the rated absorbable energy of the MOV module and the effective absorbed energy of the MOV module. The effective absorbed energy of the MOV module is:

[0060]

[0061] In the formula, E n U represents the effective absorbed energy of the MOV component, U represents the protection level of the IGCT converter valve arrester, and I represents the effective absorbed energy. n Let N be the arm current at the nth sampling time, T be the arm current sampling interval, and N be the ratio of the total time the MOV module is engaged to the current sampling interval T.

[0062] Furthermore, the number of MOV components is half the number of controllable switching devices connected in series in the converter valve body, and two adjacent controllable switching devices are connected in series and then connected in parallel with one MOV component.

[0063] Furthermore, the controllable switching device connected in series in the converter valve body is an IGCT. Attached Figure Description

[0064] Figure 1 This is a flowchart of the MOV energy over-limit active shutdown method of the converter valve assembly of the present invention;

[0065] Figure 2 This is a topology diagram of the IGCT converter valve of the present invention;

[0066] Figure 3 This is a schematic diagram of the DC current setting function curve of the present invention. Detailed Implementation

[0067] This invention employs an active shutdown strategy for MOV (Mobile Oxide Valve) energy over-limit conditions. This strategy utilizes effective handling methods under varying effective absorbable energy levels of the MOV to enhance its overheat protection capability, ensuring safe and reliable equipment operation and improving the safety and stability of the power grid system. To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0068] Implementation method for active shutdown of MOV energy over-limit in converter valve assembly:

[0069] Currently, commutation after the converter valve is actively shut off involves the participation of the mobile virtual transformer (MOV) module in the current flow, and the energy accumulation of the MOV module must be considered. To further improve the overheat protection capability of the MOV module, this invention proposes an active shutdown control strategy for energy exceeding limits. Considering the cooling requirements of the MOV module, this strategy aims to ensure the safe and reliable operation of the equipment while guaranteeing the safe and stable operation of the device, thereby improving the safety and stability performance of the power grid system.

[0070] The present invention discloses an active shutdown method for MOV energy over-limit in a converter valve assembly, which is applied to an IGCT converter valve. The topology of the IGCT converter valve is shown below. Figure 2 As shown, the IGCT converter valve mainly consists of an IGCT, a dynamic voltage equalization circuit, a static voltage equalization resistor, a modular MOV assembly, a saturated reactor, and a valve surge arrester. The IGCT includes IGCT elements and an integrated IGCT control unit. The modular MOV assembly is composed of an oxide resistive element MOV body and a fuse connected in series, primarily providing overvoltage protection and absorbing shutdown energy for the IGCT body. Furthermore, in this embodiment, the number of modular MOV assemblies is half the number of IGCT elements, specifically two adjacent IGCT elements connected in series followed by one modular MOV assembly in parallel. When the IGCT receives an active shutdown command, the system initiates modular MOV energy calculation. The specific process of this IGCT converter valve modular MOV energy over-limit protection method is as follows: Figure 1 As shown below, a detailed introduction will follow.

[0071] Step 1: After the system detects the active shutdown signal, the system starts the effective absorbed energy E of the MOV component. n Calculate and determine the remaining effective absorbable energy E of the MOV module based on its rated absorbable energy. R The calculation.

[0072] The effective absorbed energy of the MOV component is calculated using an integral formula, specifically:

[0073]

[0074] In the formula, E nU represents the effective absorbed energy of the MOV component, U is the protection level of the IGCT converter valve arrester, I is the arm current, and T is the arm current sampling interval. n Let N be the arm current at the nth sampling time, where N is the ratio of the total time the MOV component is engaged to the current sampling interval T.

[0075] The remaining effective absorbable energy E of the MOV component R for:

[0076] E R =E T - E n

[0077] In the formula, E R E represents the remaining effective absorbable energy of the MOV component. T The rated energy absorbed by the MOV component.

[0078] Step two: Determine the remaining effective absorbable energy of the MOV component:

[0079] When the remaining absorbable energy E of the component MOV R Less than or equal to the minimum absorbable energy design value E L At that time, i.e., E R ≤E L Then the IGCT converter valve directly disables the active shutdown function, and the MOV module enters a natural heat dissipation state, that is, a self-recovery state of absorption capacity. The MOV module recovers its energy absorption capacity at a certain rate. Under natural heat dissipation, the energy absorption capacity K (kJ / min) recovered by the MOV module per unit time is the remaining effective absorbable energy of the surge arrester at this time. R =E R0 +K×ΔT,E R E represents the remaining effective absorbable energy of the MOV in its real-time self-recovery state. R0 K represents the remaining effective absorbable energy of the MOV before it reaches a self-recovery state, and K represents the energy absorption capacity of the MOV unit under natural heat dissipation conditions. The time during which the absorption capacity is in a self-recovery state. The remaining effective absorbable energy E of the MOV component. R Greater than or equal to E H At that time, i.e., E R ≥E H If the IGCT converter valve is then re-unlocked, the active shutdown function is reset. The system then re-evaluates whether an active shutdown signal exists. If not, the MOV component remains in its absorption capacity self-recovery state; if it does exist, step one is repeated.

[0080] When the remaining absorbable energy E of the component MOV R Greater than the minimum absorbable energy design value EL And less than or equal to the reduced current setting value E M At that time, i.e., E L <E R ≤E M This causes the converter valve to operate by reducing the DC current according to a set function. Furthermore, the reduced DC current is positively correlated with the remaining effective absorbable energy of the MOV module. As a specific embodiment, the reduced DC current and the remaining effective absorbable energy of the MOV module exhibit a linear positive correlation; that is, the greater the remaining effective absorbable energy of the MOV module, the greater the DC current, and vice versa. Further, the set DC current function can be set as follows: The unit is pu, and its curve is as follows: Figure 3 As shown. It should be noted that the reduction of DC current here actually employs a specific control strategy to control the IGCT converter valve, achieving a DC current that is a function of the DC current set above. Then, it re-evaluates whether an active shutdown signal exists. If not, the module MOV remains in its self-recovery state; if it does, step one is repeated. Furthermore, the purpose of reducing DC current here is to reduce the potential overvoltage energy generated in the system when the module MOV's protection capability weakens, thus preventing MOV overload failure and protecting the converter valve and the entire system's safe and stable operation. This is a preventative, proactive operating strategy that balances system performance and equipment safety, and is particularly important when the module MOV is in poor condition.

[0081] When the remaining absorbable energy E of the component MOV R Greater than the reduced current setting value E M And less than or equal to the minimum absorbable energy design value E H At that time, i.e., E M <E R ≤E H Then the MOV component enters a natural heat dissipation state, i.e., a self-recovery state of absorption capacity. The MOV component recovers its energy absorption capacity at a certain rate. Under natural heat dissipation, the energy absorption capacity K (kJ / min) recovered by the MOV component per unit time is... At this time, the remaining effective absorbable energy of the surge arrester is... E R E represents the remaining effective absorbable energy of the MOV in its real-time self-recovery state. R0 K represents the remaining effective absorbable energy of the MOV before it reaches a self-recovery state, and K represents the energy absorption capacity of the MOV unit under natural heat dissipation conditions. This is the time the component remains in the self-recovery state of absorption capacity. Then, it re-evaluates whether an active shutdown signal exists. If not, the MOV component continues in the self-recovery state of absorption capacity; if so, step one is repeated.

[0082] Among them, E L <E M <E H Furthermore, all three parameters can be set based on the rated energy absorbed by the MOV component.

[0083] This cycle repeats continuously, further enhancing the overheat protection capability of the MOV components, ensuring the safe and reliable operation of the equipment, and improving the safety and stability of the power grid system.

[0084] The following specific example will be used to further illustrate the solution that this invention aims to protect.

[0085] The flowchart of the IGCT converter valve assembly MOV energy over-limit active shutdown control strategy is as follows: Figure 1 As shown, when the IGCT receives the active shutdown command, the system initiates the MOV energy calculation and determines the remaining absorbable energy based on the MOV's rated absorbable energy (here, the residual voltage of the valve arrester is no greater than 130kV, so U is taken as 130kV; the optical CT is used to sample the bridge arm current, and the sampling interval T of the optical CT is 4μs). Furthermore, the rated absorbable energy E of a single bridge arm without redundant MOV components... T 1500kJ; E L This is the minimum absorbable energy design value, which is also the guaranteed remaining absorbable energy value of the MOV module. In this implementation, it is taken as 0.1 times the rated absorbable energy E. T That is, 150kJ; E H The maximum absorbable energy design value is set here to half the rated absorbable energy of the MOV arm assembly, which is 750 kJ; E M To reduce the current setting (remaining absorbable energy setting for reduced current operation), E is set here. M It is 1 / 4 of the rated absorbed energy of the MOV arm assembly, taken as 375kJ.

[0086] like Figure 1 As shown, after the IGCT converter valve control system is powered on, it checks the initial state of the self-test component MOV to see if the active shutdown command is valid. If invalid, no active shutdown logic is executed; if valid, the component MOV determines the remaining effective absorbable energy. Assuming the absorbed energy is E1, then E... R =E T -E1, determines the remaining absorbable energy E of the MOV component. R Does E satisfy? R ≤E L (150kJ).

[0087] If E RIf the energy consumption is ≤150kJ, the active shutdown function will be directly disabled, and the MOV component will enter a natural heat dissipation state. At this time, the MOV component will restore its energy absorption capacity at a certain rate. Where K is the energy absorption capacity (kJ / min) recovered per unit time under natural heat dissipation of the MOV component, and in this embodiment K=3.61kJ / min. The interval time (min); when the remaining effective absorbable energy of the component MOV is greater than or equal to E H At that time, i.e., E R ≥750kJ unlocks the active shutdown function.

[0088] If E L <E R ≤E M That is, 150kJ < E R If the current is ≤375kJ, the DC current will be reduced according to the set function, which is I=(E R -150) / 225, unit pu.

[0089] If E M <E R ≤E H The MOV component enters a natural heat dissipation state, at which point the MOV component recovers its energy absorption capacity at a certain rate. Where K is the energy absorption capacity (kJ / min) recovered per unit time under natural heat dissipation of the MOV component, and in this embodiment K=3.61kJ / min. The interval time is in minutes.

[0090] The above implementation can further improve the overheat protection capability of the MOV module, providing support for the safe and stable operation of the power grid system.

[0091] Example of a converter valve controller:

[0092] This invention discloses a converter valve controller, the core function of which is to accurately, reliably, and safely control the on / off switching of a large number of controllable switching devices in the converter valve, thereby achieving stable system operation and power control. Specifically, it includes a memory, a processor, and an internal bus. The processor and memory communicate and interact with each other via the internal bus. The memory includes at least one software functional module stored in the memory. The processor executes various functional applications and data processing by running the software programs and modules stored in the memory, implementing the steps of the converter valve assembly MOV energy over-limit active shutdown method described in the embodiments of this invention. The processor can be a microprocessor (MCU), a programmable logic device (FPGA), or other processing devices. The memory can be various types of memory that store information using electrical energy, such as RAM, ROM, etc., or other types of memory.

[0093] The core of this active shutdown method for MOV energy over-limit in converter valve assembly is as follows:

[0094] After detecting the active shut-off converter valve signal, the remaining effective absorbable energy of the MOV component is calculated in real time:

[0095] If the remaining effective absorbable energy is less than or equal to the minimum absorbable energy design value, the active shut-off function of the converter valve is disabled, and the MOV module is in a self-recovery state of absorption capacity. The active shut-off function of the converter valve is unlocked after the remaining effective absorbable energy of the MOV module recovers to greater than or equal to the maximum absorbable energy design value.

[0096] If the remaining effective absorbable energy is greater than the minimum absorbable energy design value and less than or equal to the reduced current setting value, the converter valve is controlled to reduce the DC current. Moreover, the reduced DC current is positively correlated with the remaining effective absorbable energy of the MOV module, and may even be a positively correlated linear relationship.

[0097] If the remaining effective absorbable energy is greater than the reduced current setting value and less than or equal to the maximum absorbable energy design value, the MOV component is in a self-recovery state of absorption capacity.

[0098] The minimum absorbable energy design value is less than the reduced current setting value, and the reduced current setting value is less than the maximum absorbable energy design value.

[0099] For a more detailed explanation of the processing procedure and principle of this method, please refer to the description of the implementation method for the active shutdown of MOV energy over-limit in the converter valve assembly.

[0100] Implementation method of the converter valve:

[0101] The present invention discloses a converter valve whose main purpose is to safely, reliably, and efficiently convert electrical energy between AC and DC in various electrical environments. It serves as the cornerstone for achieving long-distance, high-capacity, and flexible interconnection in modern large-scale power grids. It consists of thousands of controllable switching devices and their auxiliary circuits.

[0102] This implementation uses a reverse-resistance type IGCT as the controllable switching device, which can reduce the power surge to the AC system and improve the safe and stable operation of the large power grid. Its topology is shown below. Figure 2 As shown, the IGCT converter valve mainly consists of an IGCT, a dynamic voltage equalization circuit, a static voltage equalization resistor, a modular MOV assembly, a saturated reactor, and a valve arrester (also known as the converter valve body). The IGCT includes a GCT element and an IGCT integrated control unit. The modular MOV assembly is composed of an oxide resistive element MOV body and a fuse connected in series, mainly providing overvoltage protection and absorbing shutdown energy for the IGCT body. Moreover, the number of modular MOV assemblies is half the number of controllable switching devices connected in series in the converter valve body, and two adjacent controllable switching devices are connected in series and then connected in parallel with one modular MOV assembly.

[0103] In addition, the converter valve also includes a converter valve controller, which includes a processor. The processor executes a computer program to implement the steps of the converter valve assembly MOV energy over-limit active shutdown method of the present invention. The core content of this method is:

[0104] After detecting the active shut-off converter valve signal, the remaining effective absorbable energy of the MOV component is calculated in real time:

[0105] If the remaining effective absorbable energy is less than or equal to the minimum absorbable energy design value, the active shut-off function of the converter valve is disabled, and the MOV module is in a self-recovery state of absorption capacity. The active shut-off function of the converter valve is unlocked after the remaining effective absorbable energy of the MOV module recovers to greater than or equal to the maximum absorbable energy design value.

[0106] If the remaining effective absorbable energy is greater than the minimum absorbable energy design value and less than or equal to the reduced current setting value, the converter valve is controlled to reduce the DC current. Moreover, the reduced DC current is positively correlated with the remaining effective absorbable energy of the MOV module, and may even be a positively correlated linear relationship.

[0107] If the remaining effective absorbable energy is greater than the reduced current setting value and less than or equal to the maximum absorbable energy design value, the MOV component is in a self-recovery state of absorption capacity.

[0108] The minimum absorbable energy design value is less than the reduced current setting value, and the reduced current setting value is less than the maximum absorbable energy design value.

[0109] For a more detailed explanation of the processing procedure and principle of this method, please refer to the description of the implementation method for the active shutdown of MOV energy over-limit in the converter valve assembly.

[0110] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit its protection scope. Although the present application has been described in detail with reference to the above embodiments, those skilled in the art should understand that after reading the present application, they can still make various changes, modifications or equivalent substitutions to the specific implementation of the application. However, all such changes, modifications or equivalent substitutions are within the protection scope of the claims of the present invention.

Claims

1. A method for active shutdown of MOV (Multi-Vehicle Engine) assembly energy exceeding limits, characterized in that, include: After detecting the active shut-off converter valve signal, the remaining effective absorbable energy of the MOV component is calculated in real time: If the remaining effective absorbable energy is less than or equal to the minimum absorbable energy design value, the active shut-off function of the converter valve is disabled, and the MOV module is in a self-recovery state of absorption capacity. The active shut-off function of the converter valve is unlocked after the remaining effective absorbable energy of the MOV module recovers to greater than or equal to the maximum absorbable energy design value. If the remaining effective absorbable energy is greater than the minimum absorbable energy design value and less than or equal to the current reduction setting value, then control the converter valve to reduce the DC current. If the remaining effective absorbable energy is greater than the reduced current setting value and less than or equal to the maximum absorbable energy design value, the MOV component is in a self-recovery state of absorption capacity. The minimum absorbable energy design value is less than the reduced current setting value, and the reduced current setting value is less than the maximum absorbable energy design value.

2. The method for active shutdown of MOV energy exceeding limits in the converter valve assembly according to claim 1, characterized in that, The reduced DC current is positively correlated with the remaining effective absorbable energy of the MOV component.

3. The method for active shutdown of MOV energy exceeding limit in the converter valve assembly according to claim 2, characterized in that, The reduced DC current has a positive linear relationship with the remaining effective absorbable energy of the MOV component.

4. The method for active shutdown of MOV energy exceeding limit in the converter valve assembly according to claim 3, characterized in that, The formula for calculating the reduced DC current is: ； In the formula, I 设定 To reduce the DC current, E R E represents the remaining effective absorbable energy of the MOV component. L E is the minimum absorbable energy design value. M To reduce the current setting value.

5. The method for active shutdown of MOV energy exceeding limit in a converter valve assembly according to any one of claims 1 to 4, characterized in that, Under the self-recovery state of the absorption capacity MOV component, the remaining effective absorbable energy of the MOV is: ； In the formula, E R E represents the remaining effective absorbable energy of the MOV in its real-time self-recovery state. R0 K represents the remaining effective absorbable energy of the MOV before it reaches a self-recovery state, and K represents the energy absorption capacity of the MOV unit under natural heat dissipation conditions. This refers to the time during which the absorption capacity is in a self-recovery state.

6. The method for active shutdown of MOV energy exceeding the limit in a converter valve assembly according to any one of claims 1 to 4, characterized in that, The remaining effective absorbable energy of the MOV module is the difference between the rated absorbable energy of the MOV module and the effective absorbed energy of the MOV module. The effective absorbed energy of the MOV module is: ； In the formula, E n U represents the effective absorbed energy of the MOV component, U represents the protection level of the IGCT converter valve arrester, and I represents the effective absorbed energy. n Let N be the arm current at the nth sampling time, T be the arm current sampling interval, and N be the ratio of the total time the MOV module is engaged to the current sampling interval T.

7. A converter valve controller, comprising a processor, characterized in that, The processor executes a computer program to implement the steps of the method according to any one of claims 1 to 6.

8. A converter valve, comprising a converter valve body and a converter valve controller, the converter valve body including an assembly MOV, and the converter valve controller including a processor, characterized in that, The processor executes a computer program to implement the steps of the method according to any one of claims 1 to 6.

9. The converter valve according to claim 8, characterized in that, The number of MOV components is half the number of controllable switching devices connected in series in the converter valve body. Two adjacent controllable switching devices are connected in series and then connected in parallel with one MOV component.

10. The converter valve according to claim 8, characterized in that, The controllable switching device connected in series in the converter valve body is an IGCT.

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