Hybrid commutation converter control system and main / standby switching method thereof

Abstract

The invention relates to a hybrid commutation converter control system and a main / standby switching method thereof, and belongs to the technical field of converters. The priority of the VBE self-checking signal and the priority of the HCC operation mode signal are considered, whether switching is needed or not is judged according to the VBE self-checking signal of the system and the VBE self-checking signal of the system, on the basis that the VBE self-checking signal is normal, the HCC operation mode signal is newly added for switching control, and whether switching is needed or not is controlled according to whether the HCC operation mode signal is normal or not. According to the invention, the main / standby switching of the HCC converter control system is realized, the system can be maintained to operate in the HCC mode as far as possible under the condition that the system does not exit operation, and the capability of the hybrid commutation converter for resisting commutation failure in the HCC mode is fully exerted, so that the impact of the commutation failure on an alternating current power grid is effectively reduced, and the reliability of the system is improved. The method has very high engineering application value.

Description

Technical Field

[0001] This invention relates to a hybrid commutation converter control system and its main / standby switching method, belonging to the field of converter technology. Background Technology

[0002] Line commutated converters (LCCs), which use thyristors as their basic components, only have controllable turn-on capability and lack controllable turn-off capability, thus only having one LCC operating mode. When AC system faults occur, commutation failure is prone to occur, leading to a surge in current and a rapid and significant loss of DC transmission power. In areas with multiple DC feeds, when the AC system fails, multiple DC lines may experience simultaneous or sequential commutation failures, with even more severe consequences. Hybrid commutated converters (HCCs), on the other hand, use IGCTs as their basic components and possess controllable turn-on and controllable turn-off capabilities. Furthermore, hybrid commutated converters can use the controllable turn-off function (HCC operating mode) or not (LCC operating mode), thus having both HCC and LCC operating modes.

[0003] Hybrid commutated converters (HCC converters) are an emerging technology, and currently there is no method for switching between primary and backup systems. The best reference is the switching method for primary and backup systems in grid commutated converters (LCC converters). In LCC converters, the pole control (PCP) and valve control (VBE) systems rely on the VBE_OK signal for switching, resulting in a clear structure and a simple implementation method that only requires considering the VBE_OK signal. However, HCC converters, in addition to the VBE_OK signal, also have an HCC_OK signal, with a priority relationship between the two signals. Furthermore, they involve both HCC and LCC operating modes, making the primary and backup system switching method relatively complex. Currently, there is a lack of research on primary and backup switching in hybrid commutated converter control systems. Summary of the Invention

[0004] The purpose of this invention is to provide a hybrid commutator converter control system and its master / standby switching method to solve the problem that the master / standby switching of the current LCC converter control system is not applicable to HCC converters, thus resulting in a lack of effective control over the master / standby switching of the HCC converter control system.

[0005] To solve the above-mentioned technical problems, this invention provides a method for master / slave switching in a hybrid commutator control system, the method comprising: Acquire the VBE self-test signal and HCC operating mode signal of the hybrid commutator system, as well as the VBE self-test signal and HCC operating mode signal of the hybrid converter to the system. The system determines whether a switch is needed based on the VBE self-test signal of this system and the VBE self-test signal of the system against which it is tested. If the VBE self-test signal of this system is abnormal while the VBE self-test signal of the system against which it is tested is normal, the system will be switched to run as the main system. If the VBE self-test signal of this system is normal and the VBE self-test signal of the system against which it is tested is also normal, the system determines whether a switch is needed based on the HCC running mode signal of this system and the HCC running mode signal of the system against which it is tested.

[0006] Furthermore, determining whether a switch is needed based on the HCC operating mode signal of this system and the HCC operating mode signal of the other system includes: if the HCC operating mode signal of this system is normal, then no switch is made, and this system remains as the main system; if the HCC operating mode signal of this system is abnormal but the HCC operating mode signal of the other system is normal, then the other system will be switched to run as the main system, and the other system will run in HCC mode.

[0007] Furthermore, determining whether switching is necessary based on the HCC operating mode signal of this system and the HCC operating mode signal of the system also includes: when the HCC operating mode signal of this system is abnormal and the HCC operating mode signal of the system is also abnormal, then no switching is performed, this system is kept running as the main system, the valve-controlled HCC function is identified as abnormal, and this system is controlled to switch from HCC operating mode to LCC operating mode.

[0008] Furthermore, the method also includes: when the VBE self-test signal of the system is normal but the HCC operating mode signal is abnormal, if the VBE self-test signal of the system is abnormal, then no switching is performed, the system is kept running as the main system, and the system is controlled to switch from HCC operating mode to LCC operating mode.

[0009] Furthermore, the valve control of the hybrid commutator system is only connected to the polarity control of the system, and the valve control of the hybrid commutator system is only connected to the polarity control of the system.

[0010] The beneficial effects of this invention are as follows: Considering the priority of the VBE self-test signal and the HCC operating mode signal, this invention first determines whether switching is needed based on the VBE self-test signal of the current system and the signal against the system. If the VBE self-test signal is normal, an HCC operating mode signal is added for switching control. Switching is controlled based on the normality of the HCC operating mode signal. This invention achieves master / slave switching for the HCC converter control system. Furthermore, this invention can maintain the system in HCC mode as much as possible without shutting down the system, fully leveraging the ability of the hybrid commutation converter to withstand commutation failure in HCC mode, thereby effectively reducing the impact of commutation failure on the AC power grid. This invention has high engineering application value.

[0011] The present invention also provides a hybrid commutator converter control system, including a pole controller and a valve controller with primary and backup redundancy configuration. The valve controller of this system sends the acquired VBE self-test signal and HCC operating mode signal of this system to the pole controller of this system, and the valve controller of the system sends the acquired VBE self-test signal and HCC operating mode signal of the system to the pole controller of the system. The system's polarity controller and the system first determine whether a switch is needed based on their respective VBE self-test signals. When the VBE self-test signal of the system is abnormal while the VBE self-test signal of the system is normal, the system will be switched to the main system operation. When the VBE self-test signal of the system is normal and the VBE self-test signal of the system is also normal, the system will determine whether a switch is needed based on the HCC operation mode signal of the system and the HCC operation mode signal of the system.

[0012] Furthermore, determining whether a switch is needed based on the HCC operating mode signal of this system and the HCC operating mode signal of the other system includes: if the HCC operating mode signal of this system is normal, then no switch is made, and this system remains as the main system; if the HCC operating mode signal of this system is abnormal but the HCC operating mode signal of the other system is normal, then the other system will be switched to run as the main system, and the other system will run in HCC mode.

[0013] Furthermore, determining whether switching is necessary based on the HCC operating mode signal of this system and the HCC operating mode signal of the system also includes: when the HCC operating mode signal of this system is abnormal and the HCC operating mode signal of the system is also abnormal, then no switching is performed, this system is kept running as the main system, the valve-controlled HCC function is identified as abnormal, and this system is controlled to switch from HCC operating mode to LCC operating mode.

[0014] Furthermore, when the VBE self-test signal of this system is normal but the HCC operating mode signal is abnormal, if the VBE self-test signal of the system is abnormal, no switching will be performed, and this system will continue to operate as the main system, and the system will be controlled to switch from HCC operating mode to LCC operating mode.

[0015] Furthermore, the valve control of the hybrid commutator system is only connected to the polarity control of the system, and the valve control of the hybrid commutator system is only connected to the polarity control of the system.

[0016] The beneficial effects of this invention are as follows: Considering the priority of the VBE self-test signal and the HCC operating mode signal, this invention first determines whether switching is needed based on the VBE self-test signal of the current system and the signal against the system. If the VBE self-test signal is normal, an HCC operating mode signal is added for switching control. Switching is controlled based on the normality of the HCC operating mode signal. This invention achieves master / slave switching for the HCC converter control system. Furthermore, this invention can maintain the system in HCC mode as much as possible without shutting down the system, fully leveraging the ability of the hybrid commutation converter to withstand commutation failure in HCC mode, thereby effectively reducing the impact of commutation failure on the AC power grid. This invention has high engineering application value. Attached Figure Description

[0017] Figure 1 This is a flowchart of the master / slave switching method of the hybrid commutator converter control system of the present invention. Detailed Implementation

[0018] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0019] This invention first determines whether switching is needed based on the VBE self-test signal of the system and the VBE self-test signal of the system. On the basis of normal VBE self-test signal, an HCC running mode signal is added. Whether to switch is controlled according to the normality of HCC running mode signal. This invention can keep the system running in HCC mode as much as possible without exiting the operation.

[0020] Hybrid commutator converter control system implementation method The hybrid commutated converter (HCC) control system of this invention includes pole control (PCP) and valve control (VBE). The pole control is responsible for the operation and control of the entire converter station (or pole), and its core functions include power / voltage control, operating mode decision and switching, AC system synchronization, and system-level protection and coordination. The valve control is the bridge connecting the pole control and the power valve, and is responsible for translating the macroscopic instructions of the pole control into precise actions that can directly drive power switching devices (such as IGCT). It includes a hybrid commutation controller and valve-based electronic equipment, and its core functions include pulse generation, valve status monitoring and protection, active commutation control, and low-level protection execution. To improve control reliability, the hybrid commutated converter (HCC) control system of this invention adopts a dual redundancy configuration, with one system serving as the primary system and the other as the backup system. Each system contains a corresponding pole controller (PCP) and valve controller (VBE). One of the dual-configuration hybrid commutated converter (HCC) control systems can be referred to as the "this system" (i.e., the currently running system) and the other as the "opposite system" (the system not currently running). The pole controller of the "this system" only communicates with the valve controller of the "this system," and the pole controller of the "opposite system" only communicates with the valve controller of the "opposite system." There is no cross-connection between the pole controller and the valve controller of the "this system." That is, the signal acquired by the valve controller of the "this system" is only uploaded to the pole controller of the "this system" and only receives control from the pole controller of the "this system." Similarly, the signal acquired by the valve controller of the "opposite system" is only uploaded to the pole controller of the "opposite system" and only receives control from the pole controller of the "opposite system." There is information exchange between the pole controller of the "this system" and the pole controller of the "opposite system." In addition to the VBE self-test signal, the HCC converter also has an HCC operating mode signal, and these two signals have a priority relationship. Furthermore, they involve both HCC and LCC operating modes. The master / standby switching method considers more factors compared to the LCC converter. To maintain the system in HCC mode as much as possible without shutting down the system, this invention provides a master / standby switching method for the hybrid commutator converter control system: First, it determines whether switching is needed based on the VBE self-test signal of the current system and the VBE self-test signal of the system opposite to the current system. If the VBE self-test signal of the current system is abnormal while the VBE self-test signal of the system opposite to the current system is normal, then the system is switched to master system operation. If both the VBE self-test signals of the current system and the VBE self-test signal of the system opposite to the current system are normal, then it determines whether switching is needed based on the HCC operating mode signal of the current system and the HCC operating mode signal of the system opposite to the current system. The implementation process of this method is as follows: Figure 1 As shown below, a detailed explanation will follow.

[0021] The VBE self-test signal is also called the VBE_OK signal, and the HCC operating mode signal is also called the HCC_OK signal. Both the VBE_OK and HCC_OK signals are generated by the valve-controlled system (VBE). A normal VBE_OK signal and a normal HCC_OK signal indicate that the VBE and HCC are available, respectively. The VBE continuously monitors its own key functions. The VBE self-test items include: door and drive power supply, energy storage capacitor voltage, fiber optic communication, board temperature, key component status, and electrical isolation. Only when all of the above items are normal will a normal VBE_OK signal be generated. The VBE sends these two signals to the PCP. The PCP is used for the logic judgment of switching systems and exiting operation. That is, the VBE of this system sends the VBE_OK and HCC_OK signals to the PCP of this system, and the VBE of the system to which the system is located sends the VBE_OK and HCC_OK signals to the PCP of the system to which the system is located. When HCC_OK is abnormal, the system needs to exit HCC mode, but can still run in LCC mode. When VBE_OK is abnormal, the system needs to exit operation. Therefore, the VBE_OK signal has a higher priority.

[0022] Therefore, the main / standby switching of the hybrid commutator converter control system of this invention should first consider the VBE_OK signal, and then consider the HCC_OK signal. The following describes six possible scenarios.

[0023] Scenario 1: If the VBE_OK of this system is abnormal and the VBE_OK of the other system is also abnormal, the VBE dual system is considered to be abnormal and the hybrid commutator converter control system will be shut down. Scenario 2: If the VBE_OK of this system is abnormal, but the VBE_OK of the other system is normal, then the HCC_OK signal does not need to be considered. The other system will be directly switched to the main system operation, that is, the other system is in the main running state. If the HCC_OK of the other system is normal at this time, it will run in HCC mode. If the HCC_OK of the other system is abnormal at this time, it will run in LCC mode. Scenario 3: The VBE_OK and HCC_OK of this system are normal. This system will continue to run as the primary system and will be running in HCC mode. Scenario 4: If VBE_OK is normal for this system, but HCC_OK is abnormal for this system, and VBE_OK and HCC_OK are normal for the other system, the system will be switched to main system operation, meaning the system will be in main operation state and running in HCC mode. Scenario 5: The system's VBE_OK is normal, but the system's HCC_OK is abnormal. If the system's VBE_OK is normal but the system's HCC_OK is abnormal, the system will continue to operate as the main system. At the same time, the valve-controlled HCC function is considered abnormal, and the system operation mode will be switched from HCC mode to LCC mode. Scenario 6: The system's VBE_OK is normal, but the system's HCC_OK is abnormal. If the system's VBE_OK is abnormal, keep the system running as the primary system and run in LCC mode.

[0024] Implementation of the Master / Slave Switching Method for Hybrid Commutator Control System This invention acquires the VBE self-test signal and HCC operating mode signal of the hybrid commutator system, as well as the VBE self-test signal and HCC operating mode signal of the hybrid converter to the system. First, it determines whether a switchover is needed based on the VBE self-test signal of the system and the VBE self-test signal of the system to the main system. If the VBE self-test signal of the system is abnormal while the VBE self-test signal of the system to the main system is normal, the system will be switched to main system operation. If both the VBE self-test signal of the system and the VBE self-test signal of the system to the main system are normal, it then determines whether a switchover is needed based on the HCC operating mode signal of the system and the HCC operating mode signal of the system to the main system.

[0025] The determination of whether to switch based on the HCC operating mode signal of this system and the HCC operating mode signal of the other system includes: if the HCC operating mode signal of this system is normal, no switch is made, and this system continues to operate as the master system; if the HCC operating mode signal of this system is abnormal but the HCC operating mode signal of the other system is normal, the other system will be switched to operate as the master system and will run in HCC mode; if the HCC operating mode signal of this system is abnormal and the HCC operating mode signal of the other system is also abnormal, no switch is made, this system continues to operate as the master system, the valve-controlled HCC function is identified as abnormal, and this system will be controlled to switch from HCC operating mode to LCC operating mode. If the VBE self-test signal of this system is normal but the HCC operating mode signal is abnormal, and the VBE self-test signal of the other system is also abnormal, no switch is made, this system continues to operate as the master system, and this system will be controlled to switch from HCC operating mode to LCC operating mode.

[0026] Specifically, the master / standby switching method for the hybrid commutated converter (HCC) control system of this invention targets a hybrid commutated converter (HCC) control system including a polarity controller (PCP) and a valve control system (VBE). This control system employs a dual redundancy configuration, with one serving as the master system and the other as the standby system. Each system contains corresponding polarity controllers (PCP) and valve controls (VBE). One of the dual-configuration HCC control systems can be referred to as the "current system" (i.e., the system currently running), and the other as the "parallel system" (the system not currently running). The polarity controller of the current system only communicates with the valve control of the current system, and the polarity controller of the parallel system only communicates with the valve control of the parallel system. There are no cross-connections between the polarity controllers and valve controls of the current and parallel systems. That is, the signals acquired by the valve control of the current system are only uploaded to and received from the polarity controller of the current system, and the signals acquired by the valve control of the parallel system are only uploaded to and received from the polarity controller of the parallel system. Information exchange exists between the polarity controllers of the current system and the polarity controllers of the parallel system. The implementation process of the master / standby switching method for the hybrid commutated converter control system of this invention is as follows: Figure 1 As shown below, a detailed explanation will follow.

[0027] The VBE self-test signal is also called the VBE_OK signal, and the HCC operating mode signal is also called the HCC_OK signal. Both the VBE_OK and HCC_OK signals are generated by the valve-controlled system (VBE). A normal VBE_OK signal and a normal HCC_OK signal indicate that the VBE and HCC are available, respectively. The VBE continuously monitors its own key functions. The VBE self-test items include: door and drive power supply, energy storage capacitor voltage, fiber optic communication, board temperature, key component status, and electrical isolation. Only when all of the above items are normal will a normal VBE_OK signal be generated. The VBE sends these two signals to the PCP. The PCP is used for the logic judgment of switching systems and exiting operation. That is, the VBE of this system sends the VBE_OK and HCC_OK signals to the PCP of this system, and the VBE of the system to which the system is located sends the VBE_OK and HCC_OK signals to the PCP of the system to which the system is located. When HCC_OK is abnormal, the system needs to exit HCC mode, but can still run in LCC mode. When VBE_OK is abnormal, the system needs to exit operation. Therefore, the VBE_OK signal has a higher priority.

[0028] Therefore, the main / standby switching of the hybrid commutator converter control system of this invention should first consider the VBE_OK signal, and then consider the HCC_OK signal. The following describes six possible scenarios.

[0029] Scenario 1: If the VBE_OK of this system is abnormal and the VBE_OK of the other system is also abnormal, the VBE dual system is considered to be abnormal and the hybrid commutator converter control system will be shut down. Scenario 2: If the VBE_OK of this system is abnormal, but the VBE_OK of the other system is normal, then the HCC_OK signal does not need to be considered. The other system will be directly switched to the main system operation, that is, the other system is in the main running state. If the HCC_OK of the other system is normal at this time, it will run in HCC mode. If the HCC_OK of the other system is abnormal at this time, it will run in LCC mode. Scenario 3: The VBE_OK and HCC_OK of this system are normal. This system will continue to run as the primary system and will be running in HCC mode. Scenario 4: If VBE_OK is normal for this system, but HCC_OK is abnormal for this system, and VBE_OK and HCC_OK are normal for the other system, the system will be switched to main system operation, meaning the system will be in main operation state and running in HCC mode. Scenario 5: The system's VBE_OK is normal, but the system's HCC_OK is abnormal. If the system's VBE_OK is normal but the system's HCC_OK is abnormal, the system will continue to operate as the main system. At the same time, the valve-controlled HCC function is considered abnormal, and the system operation mode will be switched from HCC mode to LCC mode. Scenario 6: The system's VBE_OK is normal, but the system's HCC_OK is abnormal. If the system's VBE_OK is abnormal, keep the system running as the primary system and run in LCC mode.

[0030] In summary, this invention adds an HCC_OK signal to the VBE_OK signal for judgment. Without shutting down the system, it maintains the system in HCC mode as much as possible, giving full play to the ability of the hybrid commutator to resist commutation failure in HCC mode. This can effectively reduce the impact of commutation failure on the AC power grid and has high engineering application value.

Claims

1. A method for master-backup switching of a hybrid commutation converter control system, characterized in that, The method comprises: obtaining VBE self-check signals and HCC operation mode signals of a system of the hybrid commutation converter, and VBE self-check signals and HCC operation mode signals of a system of the hybrid commutation converter; determining whether switching is needed according to the VBE self-check signals of the system and the VBE self-check signals of the system, and when the VBE self-check signals of the system are abnormal and the VBE self-check signals of the system are normal, switching the system to the main system; when the VBE self-check signals of the system are normal and the VBE self-check signals of the system are normal, determining whether switching is needed according to the HCC operation mode signals of the system and the HCC operation mode signals of the system.

2. The method of claim 1, wherein the method further comprises: determining whether switching is needed according to the HCC operation mode signals of the system and the HCC operation mode signals of the system, and when the HCC operation mode signals of the system are normal, not switching, and keeping the system as the main system; when the HCC operation mode signals of the system are abnormal and the HCC operation mode signals of the system are normal, switching the system to the main system and making the system operate in the HCC mode.

3. The method of claim 2, wherein the method further comprises: determining whether switching is needed according to the HCC operation mode signals of the system and the HCC operation mode signals of the system, and when the HCC operation mode signals of the system are abnormal and the HCC operation mode signals of the system are also abnormal, not switching, keeping the system as the main system, determining that the valve control HCC function is abnormal, and controlling the system to switch from the HCC operation mode to the LCC operation mode.

4. The method of claim 1, wherein the master-backup switching of the hybrid commutation converter control system is characterized by, The method further comprises: when the VBE self-check signals of the system are normal and the HCC operation mode signals are abnormal, if the VBE self-check signals of the system are abnormal, not switching, keeping the system as the main system, and controlling the system to switch from the HCC operation mode to the LCC operation mode.

5. The method of claim 1, wherein the method further comprises: The valve control of the system of the hybrid commutation converter is connected only with the pole control of the system, and the valve control of the system of the hybrid commutation converter is connected only with the pole control of the system.

6. A hybrid commutation converter control system comprising a pole control and a valve control in a main-backup redundant configuration, characterized in that: the valve control of the system sends the obtained VBE self-check signals and HCC operation mode signals of the system to the pole control of the system, and the valve control of the system sends the obtained VBE self-check signals and HCC operation mode signals of the system to the pole control of the system; the pole control of the system and the pole control of the system determine whether switching is needed according to the VBE self-check signals of the system and the VBE self-check signals of the system, and when the VBE self-check signals of the system are abnormal and the VBE self-check signals of the system are normal, switching the system to the main system; when the VBE self-check signals of the system are normal and the VBE self-check signals of the system are normal, determining whether switching is needed according to the HCC operation mode signals of the system and the HCC operation mode signals of the system.

7. The hybrid commutation inverter control system of claim 6, wherein, According to the HCC operation mode signal of the system and the HCC operation mode signal of the system, it is judged whether switching is needed, which comprises: when the HCC operation mode signal of the system is normal, no switching is needed, and the system keeps running as the main system; when the HCC operation mode signal of the system is abnormal and the HCC operation mode signal of the system is normal, the system is switched to run as the main system, and the system runs in the HCC mode.

8. The hybrid commutation inverter control system of claim 7, wherein, According to the HCC operation mode signal of the system and the HCC operation mode signal of the system, it is judged whether switching is needed, which further comprises: when the HCC operation mode signal of the system is abnormal and the HCC operation mode signal of the system is also abnormal, no switching is needed, the system keeps running as the main system, it is determined that the valve control HCC function is abnormal, and the system is switched from the HCC operation mode to the LCC operation mode.

9. The hybrid commutation inverter control system of claim 6, wherein, When the VBE self-check signal of the system is normal and the HCC operation mode signal is abnormal, if the VBE self-check signal of the system is abnormal, no switching is needed, the system keeps running as the main system, and the system is switched from the HCC operation mode to the LCC operation mode.

10. The hybrid commutation inverter control system of claim 6, wherein, The valve control of the hybrid phase-change current converter is connected with the pole control of the system only, and the valve control of the hybrid phase-change current converter of the system is connected with the pole control of the system only.

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