Protection configuration system and method for direct current energy consumption device

Abstract

The invention relates to the technical field of flexible direct-current power transmission, in particular to a protection configuration system and method for a direct-current energy consumption device. A function list of the valve control device serving as a protection configuration function carrier is provided, three energy consumption device protection functions are achieved through the valve control device, and the protection scheme of each function is described in detail. The method can be applied to the flexible direct current power transmission system, and can effectively guarantee the safe operation of the ultra / extra-high voltage flexible power transmission system.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of flexible direct current power transmission, in particular to a protection configuration system and method of a direct current energy consumption device. BACKGROUND

[0002] Flexible direct current power transmission technology is a main technical means for solving offshore wind power grid connection. However, when the receiving end AC power grid fails, the wind farm energy that cannot be consumed in time will cause the direct current voltage to rise rapidly, which threatens the safety of the converter valve and the entire system. Therefore, the direct current energy consumption device is needed to consume the energy that the system cannot normally transmit, so as to stabilize the direct current voltage and assist the system to complete fault ride-through.

[0003] Controllable high-power semiconductor switching devices are an important part of the research on direct current energy consumption devices. At present, the integrated gate-commutated thyristor (IGCT) and the insulated gate bipolar transistor (IGBT) are mainly used as controllable switching devices in the direct current energy consumption device scheme.

[0004] There are mainly two types of technical routes for the direct current energy consumption device. One is the centralized energy consumption device with resistors. The other is the distributed energy consumption device with resistors. The centralized energy consumption device mainly concentrates the energy consumption resistors on both sides of the poles, and is arranged outside the valve hall in actual application. The energy consumption resistors meet the natural cooling requirements. The distributed energy consumption device distributes the energy consumption resistors in each module between the poles. The cooling of the energy consumption resistors requires a water cooling device.

[0005] The flexible chopper type direct current energy consumption device is a modular direct current energy consumption device based on full-controlled devices. Its basic principle is to realize the consumption of surplus power on the centralized resistors by using the current flexible chopping method.

[0006] The existing modular direct current energy consumption device scheme mainly uses power modules similar to the modular multilevel converter (MMC), and the protection configuration scheme is relatively mature. The flexible chopper type direct current energy consumption device adopts the IGCT straight string method, and also designs a scheme in which the IGCT switching device is connected in parallel with the RCD buffer circuit. It is a brand-new electrical topology, and its working principle is quite different from the existing schemes. The protection configuration scheme of the direct current energy consumption device is an important guarantee for the stable and safe operation of the equipment. However, the protection configuration scheme for the flexible chopper type direct current energy consumption device is in a state of deficiency, which is not conducive to the safe operation of the equipment. SUMMARY

[0007] In view of the above problems, the present application provides a protection configuration system and method of a direct current energy consumption device, which is used to solve the control and protection problems of the flexible chopper type direct current energy consumption device.

[0008] A protection configuration system of a direct current energy consumption device, comprising:

[0009] a system-level protection unit, a power module-level protection unit, and a valve control device fault protection unit;

[0010] The system-level protection unit, the power module-level protection unit, and the valve control device fault protection unit realize control and protection of a flexible chopper type direct current energy consumption device through a valve control device VCM.

[0011] The system-level protection unit is used for system-level fault protection and comprises an energy consumption device bypass sub-module number out-of-limit protection subunit, a power module overall overvoltage protection subunit, and an electrical quantity protection subunit.

[0012] The power module-level protection unit is used for power module fault protection and is completed through a valve control device, a sub-module control board PMC, and a matched execution element.

[0013] The valve control device fault protection unit is used for valve control device fault protection and comprises software and hardware faults, communication faults, and power supply fault protection detected by a valve control system.

[0014] Further, the energy consumption device bypass sub-module number out-of-limit protection subunit is used for:

[0015] When the number of energy consumption valve fault power modules exceeds the allowed bypass number, the energy consumption device bypass sub-module number out-of-limit protection subunit acts to lock the energy consumption valve.

[0016] Further, the power module overall overvoltage protection subunit is used for:

[0017] When the energy consumption valve power module capacitor voltage exceeds an overvoltage lock value, the energy consumption device power module overall overvoltage lock protection subunit acts to lock the energy consumption valve.

[0018] When the energy consumption valve power module capacitor voltage exceeds an overvoltage tripping value, the energy consumption device power module overall overvoltage tripping protection subunit acts to lock the energy consumption valve and simultaneously apply for tripping.

[0019] Further, the electrical quantity protection subunit is used for:

[0020] The measurement circuit and discrimination logic of the electrical quantity protection are configured according to the two-out-of-three principle to realize overcurrent protection, current rise rate protection, and current differential protection of the energy consumption device.

[0021] Further, the measurement circuit and discrimination logic of the electrical quantity protection are configured according to the two-out-of-three principle and comprise:

[0022] Three independent measuring devices are configured for the measuring circuit. The measuring signals are connected to the valve control device via optical fiber. The protection logic in the valve control device judges the three independent measuring signals respectively. The action result is input into the three-out-of-two judgment logic. After comprehensive judgment, it is sent to the main control CPU board of the valve control host through the high-speed communication link. The main control CPU board then blocks the energy-consuming valve through the downlink communication link, or requests the system to trip through the uplink or relay contact.

[0023] Furthermore, overcurrent protection for energy-consuming devices is implemented, including:

[0024] The positive and negative input currents are judged separately. If the measured current at either end exceeds the overcurrent protection threshold, it is judged as a protection action and the energy consumption valve is locked.

[0025] If the current continues to rise after the energy dissipation valve is locked and exceeds the trip setting, and the duration exceeds the overcurrent protection time threshold of 0.5ms, then a trip request will be immediately submitted to the upper-level control and protection equipment.

[0026] The fast overcurrent protection for energy-consuming devices serves as a rapid protection against energy-consuming valve failures. The sampling rate of the positive and negative input current measurement data of the energy-consuming device is not lower than the sampling rate threshold of 100ksps, the total delay of the measurement circuit is not greater than the total delay threshold of 70μs, and the delay of the valve-controlled fast protection circuit is less than the fast protection circuit delay threshold of 25us.

[0027] Furthermore, current rise rate protection includes:

[0028] Used to quickly lock the energy-consuming valve when a serious system failure causes a rapid increase in the current of the energy-consuming device.

[0029] The positive and negative incoming currents are judged separately. If the current rise rate at either end exceeds the current rise rate threshold, it is judged as a protection action and the energy consumption valve is locked.

[0030] The sampling rate of the positive and negative input current measurement data of the energy-consuming device is not lower than the sampling rate threshold of 100ksps, the total delay of the measurement circuit is not greater than the total delay threshold of 70μs, and the delay of the valve-controlled fast protection circuit is less than the fast protection circuit delay threshold of 25us.

[0031] Furthermore, current differential protection includes:

[0032] Based on the measured currents at both ends of the energy-consuming device, the differential current and braking current of the energy-consuming device are calculated, and the presence of a fault is determined based on the differential relay; the formula for calculating the differential current is as follows:

[0033] i d =i1+i2

[0034] Where i di1 is the differential current; i2 is the positive input current of the energy-consuming device; i3 is the negative input current of the energy-consuming device.

[0035] The formula for calculating braking current is as follows:

[0036] i r =i1-i2

[0037] Where i r This is the braking current;

[0038] The operating conditions for the differential relay are as follows:

[0039]

[0040] Where I op0 The differential starting current setting; k s I is the braking coefficient; n Rated current;

[0041] When the differential relay of the differential protection of the energy-consuming device operates, it confirms that the energy-consuming valve is locked for 1ms; if the duration of the operation exceeds the differential protection time threshold of 40ms, it requests the upper-level control protection to trip.

[0042] Furthermore, it also includes:

[0043] After any system-level protection action is activated, the valve control device immediately locks the energy-consuming valve, triggers fault recording, and sends SOE event information to the local human-machine interface and monitoring system.

[0044] Furthermore, the electrical quantity protection subunit determines the protection configuration based on the first mapping relationship, including:

[0045] Based on the first mapping relationship, the exit method is determined according to the protection settings and conditions;

[0046] The first mapping relationship is an electronic spreadsheet that records the correspondence between protection settings and conditions and exit methods;

[0047] Based on the protection settings and conditions, the export method is determined by consulting the aforementioned spreadsheet;

[0048] The configuration of electrical quantity protection is determined based on the protection settings, conditions, and output method.

[0049] Furthermore, the power module-level protection unit is specifically used for:

[0050] The PMC uses an FPGA as the main control chip to control and protect the sub-modules' operating modes and detect their status. The PMC receives and processes control commands from the valve control device to control the power module's operation. The PMC detects the health status of each device in the power module, makes a fault judgment, and sends it to the valve control device. After receiving the module fault information, the valve control device issues a bypass command to the faulty power module when the number of faulty modules is less than the number of allowed bypass modules.

[0051] Power module-level faults include: power device faults, self-powered power supply faults, undervoltage and overvoltage faults, bypass switch failures, board power supply faults, and downlink fiber optic communication faults.

[0052] Furthermore, the power module-level protection unit determines the protection configuration based on the second mapping relationship, including:

[0053] Based on the second mapping relationship, the exit method is determined according to the protection settings and conditions;

[0054] The second mapping relationship is an electronic spreadsheet that records the correspondence between protection settings and conditions and export methods;

[0055] Based on the protection settings and conditions, the export method is determined by consulting the aforementioned spreadsheet;

[0056] The power module-level protection configuration is determined based on the protection settings, conditions, and output method.

[0057] Furthermore, the valve control equipment fault protection unit is specifically used for:

[0058] For valve control equipment fault protection, after the threshold is reached, the valve control device first requests the polar controller to switch the system and records the relevant fault information and sends it to the background.

[0059] If the backup system is unavailable or the fault persists after switching systems, the valve controller will lock the energy-consuming valve to protect the safety of the primary equipment. At the same time, it will send the energy-consuming valve lockout status to the polar controller and record and send the relevant fault information to the background.

[0060] Furthermore, the valve-controlled equipment fault protection unit determines the protection configuration based on a third mapping relationship, including:

[0061] Based on the third mapping relationship, the exit method is determined according to the protection settings and conditions;

[0062] The third mapping relationship is an electronic spreadsheet that records the correspondence between protection settings and conditions and exit methods;

[0063] Based on the protection settings and conditions, the export method is determined by consulting the aforementioned spreadsheet;

[0064] The fault protection configuration of the valve control equipment is determined based on the protection settings, conditions, and outlet method.

[0065] A protection configuration method for a DC energy-consuming device, based on the above-mentioned protection configuration system, is used to control and protect a flexible chopper-type DC energy-consuming device.

[0066] The present invention has at least the following beneficial effects:

[0067] This invention proposes a functional list of valve control devices as a carrier of protection configuration functions. The valve control devices realize the protection functions of three energy-consuming devices, and provide a detailed description of the protection scheme for each function.

[0068] The invention can be applied to flexible DC transmission systems, effectively ensuring the safe operation of ultra-high voltage / extra-high voltage flexible transmission systems.

[0069] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention can be realized and obtained by means of the structures pointed out in the description and the drawings. Attached Figure Description

[0070] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0071] Figure 1 This is a schematic diagram of the protection configuration system structure according to an embodiment of the present invention;

[0072] Figure 2 Logic diagram for rapid overcurrent interlocking protection of energy-consuming devices;

[0073] Figure 3 This is a logic diagram for the fast overcurrent trip protection of energy-consuming devices.

[0074] Figure 4 Logic diagram for current rise rate protection of energy-consuming devices;

[0075] Figure 5 This is a schematic diagram of DC energy consumption for wind power.

[0076] Figure 6 This is a schematic diagram of the topology of a modular DC power consumption device. Detailed Implementation

[0077] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0078] Existing modular DC power dissipation devices mainly use power modules similar to modular multilevel converters (MMCs), and their protection configurations are relatively mature. However, flexible chopper-type DC power dissipation devices employ a power module design with switching devices and RCD buffer circuits connected in parallel, and their operating principles differ significantly from existing solutions. This invention proposes a protection configuration scheme suitable for flexible chopper-type DC power dissipation devices, thereby solving the control and protection problems of flexible chopper-type DC power dissipation devices.

[0079] like Figure 1 As shown, a protection configuration system for a DC power consumption device includes:

[0080] System-level protection unit, power module-level protection unit, and valve control equipment fault protection unit;

[0081] The system-level protection unit, power module-level protection unit, and valve-controlled equipment fault protection unit, through the valve-controlled device (VCM), realize the control and protection of the flexible chopper DC energy-consuming device.

[0082] The system-level protection unit is used for system-level fault protection, including the over-limit protection subunit for the number of bypass submodules of energy-consuming devices, the overall overvoltage protection subunit for power modules, and the electrical quantity protection subunit;

[0083] The power module-level protection unit is used for power module fault protection, and it is accomplished by valve control device, sub-module control board PMC and matching actuators.

[0084] The valve control equipment fault protection unit is used to protect valve control equipment from faults, including protection against hardware and software faults, communication faults, and power supply faults detected by the valve control system.

[0085] In practice, the following methods will be adopted:

[0086] Energy-consuming device system-level protection:

[0087] The system-level protection for energy-consuming devices includes protection against exceeding the limit of the number of bypass sub-modules of energy-consuming devices, overall overvoltage protection of power modules, and electrical quantity protection.

[0088] When the number of faulty power modules of the energy-consuming valve exceeds the allowable number of bypasses, the over-limit protection of the bypass sub-modules of the energy-consuming device will activate and lock the energy-consuming valve.

[0089] When the capacitor voltage of the power module of the energy-consuming valve exceeds the overvoltage lockout value, the overall overvoltage lockout protection of the power module of the energy-consuming device will activate, locking the energy-consuming valve. When the capacitor voltage of the power module of the energy-consuming valve exceeds the overvoltage trip setting value, the overall overvoltage trip protection of the power module of the energy-consuming device will activate, locking the energy-consuming valve and simultaneously requesting a trip.

[0090] The electrical protection features configured in the valve control device include overcurrent protection for energy-consuming devices, current rise rate protection, and current differential protection, to ensure the safe and stable operation of energy-consuming equipment. Additional protections can also be added according to the owner's requirements.

[0091] To improve the reliability of protection actions and prevent malfunctions caused by measurement circuit faults or interference, the measurement circuit and discrimination logic of the electrical quantity protection are configured according to the "two out of three" principle: First, the measurement circuit requires three independent measurement devices, and the measurement signals are connected to the valve control device via optical fiber. The protection logic in the valve control device discriminates the three independent measurement signals, and the action result is input to the "two out of three" judgment logic. After comprehensive judgment, it is sent to the main control CPU board of the valve control host through a high-speed communication link. The main control CPU board then blocks the energy-consuming valve through the downlink communication link, or requests system tripping through the uplink or relay contacts. The independent discrimination of the protection logic in the two valve control hosts improves reliability.

[0092] The 3-out-of-2 logic for fast protection of energy-consuming devices is implemented by an FPGA chip. Taking overcurrent protection of energy-consuming devices as an example, the FPGA receives current signals from three independent measurement circuits. When all three circuits are normal, the protection will activate if two circuits meet the protection action criteria; otherwise, the protection will not activate. When an anomaly occurs in a measurement circuit, the protection based on that circuit's measurement data is blocked, and the protection's output criterion changes to activating any protection action if there is no data anomaly.

[0093] After any system-level protection action is activated, the valve control device immediately locks the energy-consuming valve, triggers fault recording, and sends SOE event information to the local human-machine interface and monitoring system.

[0094] 1) Rapid overcurrent protection for energy-consuming devices

[0095] When an internal fault in the energy-consuming device causes excessive current flowing through the energy-consuming valve, the valve needs to be quickly locked to prevent damage to the power module due to overvoltage and overcurrent. If, after locking the valve, the current continues to rise and exceeds the trip setting for more than 0.5ms, a trip request is immediately sent to the upper-level control and protection equipment. As a rapid protection mechanism responding to energy-consuming valve faults, the fast overcurrent protection for the energy-consuming device requires a sampling rate of at least 100ksps for the positive and negative input current measurements, a total measurement circuit delay of no more than 70μs, and a valve-controlled fast protection circuit delay of less than 25µs. Therefore, the overall delay from the current exceeding the setting to the completion of the energy-consuming device locking can be controlled within 100µs, ensuring the speed and reliability of the protection action. The operating logic of the fast overcurrent locking protection for the energy-consuming device is as follows: Figure 2 As shown.

[0096] To ensure reliable operation, the fast overcurrent trip protection for energy-consuming devices has a protection delay time of 0.5ms. The operating logic of the fast overcurrent trip protection is as follows: Figure 3 As shown.

[0097] The fast overcurrent protection of the energy-consuming device judges the positive and negative incoming currents separately. If the measured current at either end meets the action conditions, it is judged as protection action, and the energy-consuming valve is locked. If the trip logic is met, a trip request is made. If the current continues to rise after the energy-consuming valve is locked, it is considered that the energy-consuming valve is flashing or breaking down. After confirmation for 0.5ms, a trip request is made to the pole controller to stop the machine.

[0098] 2) Current rise rate protection for energy-consuming devices

[0099] The current rise rate protection for energy-consuming devices, as a supplement to the overcurrent protection for energy-consuming devices, is used to quickly lock the energy-consuming valve when a severe system fault causes a rapid rise in the current. This prevents the current from rising too quickly and causing the current value to be too high when the rapid overcurrent protection trips, exceeding the shut-off capacity of the energy-consuming valve or damaging it. To improve the reliability of the protection action, the current rise rate protection only opens when the absolute value of the current is greater than 0.05 times the rated current. As a rapid protection to respond to energy-consuming valve faults, the current rise rate protection for energy-consuming devices has the same requirements for the measurement data sampling rate and measurement loop delay as the overcurrent protection for energy-consuming devices. The logic of the current rise rate protection for energy-consuming devices is as follows: Figure 4 As shown.

[0100] Similar to the fast overcurrent protection, the current rise rate protection of the energy-consuming device distinguishes between the positive and negative incoming currents. If the measured current at either end meets the operating conditions, it is judged as a protection action, and the energy-consuming valve is locked.

[0101] 3) Differential current protection for energy-consuming devices

[0102] Differential current protection primarily reflects flashover faults of key components of energy-consuming devices to the DC bus, such as flashover faults of series reactors, energy-consuming resistors, or energy-consuming valves to the DC bus. After the differential relay of the energy-consuming device differential protection operates, it confirms that the energy-consuming valve will be locked for 1ms. If the operation duration exceeds 40ms, it requests a trip from the upper-level control protection. If the differential protection energy-consuming valve protection equipment calculates the differential current and restraining current of the energy-consuming device based on the measured currents at both ends of the energy-consuming device, it determines whether a fault exists based on the differential relay. The differential current calculation formula is as follows:

[0103] i d =i1+i2

[0104] Where i d i1 is the differential current; i2 is the positive input current of the energy-consuming device; i3 is the negative input current of the energy-consuming device.

[0105] The formula for calculating braking current is as follows:

[0106] i r =i1-i2

[0107] Where i r This is the braking current.

[0108] The differential relay operating equation is as follows:

[0109]

[0110] Where I op0 The differential starting current setting; k s I is the braking coefficient; n This is the rated current.

[0111] 4) List of system-level protection functions

[0112] After the system-level protection of the energy-consuming device activates, in order to protect the safety of the primary equipment of the energy-consuming valve, the valve controller immediately locks the energy-consuming valve, triggers the device fault recording, and simultaneously sends the action information to the local human-machine interface and the monitoring backend. For tripping protection, in addition to completing the above operations, a tripping signal is output and a tripping request is sent to the polar controller, thereby completing fault isolation. The first mapping relationship is shown in Table 1.

[0113] Table 1 List of Electrical Quantity Protection Functions

[0114]

[0115]

[0116] Power module-level protection for energy-consuming valves:

[0117] The power module-level protection of the energy-consuming valve primarily reflects power module failures. This protection function is jointly implemented by the valve control device, the submodule control board (PMC), and its associated actuators. The PMC uses an FPGA as the main control chip to control, protect, and monitor the operating mode and status of the submodule. On one hand, it receives and processes control commands from the valve control device to control the power module's operation; on the other hand, it detects the health status of each device in the power module, makes a fault judgment, and sends it to the valve control device. After receiving the module fault information, the valve control device issues a bypass command to the faulty power module if the number of faulty modules is less than the allowed number of bypass modules.

[0118] 1) Power module level protection types and operation descriptions

[0119] Power module-level faults mainly include the following types: power device faults, self-powered power supply faults, undervoltage and overvoltage faults, bypass switch failure, board power supply faults, and downlink fiber optic communication faults. For all power module faults, after the power module reports the fault to the valve controller, the valve controller will issue a bypass command. Upon receiving the bypass command from the valve controller, the submodule triggers the bypass switch to complete the power module bypass. In the case of a downlink fiber optic communication fault, the submodule will automatically complete the power module bypass operation once the bypass switch regains its operational capability.

[0120] 2) List of power module-level protection functions

[0121] The list of power module-level protection functions, i.e. the second mapping relationship, is shown in Table 2.

[0122] Table 2 List of Power Module Level Protection Functions

[0123]

[0124]

[0125] In the event of a power module failure, the valve control device will issue a bypass command to the faulty submodule after receiving the fault information, and record and send the relevant fault information to the backend.

[0126] Valve control equipment fault protection:

[0127] 1) Fault protection types and operation descriptions for valve control equipment

[0128] Valve control equipment fault protection mainly includes protection against hardware and software faults, communication faults, and power supply faults detected by the valve control system.

[0129] For valve-controlled equipment fault protection, after the action conditions are met, in order to prevent the primary system from shutting down, the valve control device first requests a system switch from the polar controller and records and sends the relevant fault information to the backend. If the backup system is unavailable or the fault still exists after the system switch, in order to protect the safety of the primary equipment of the energy-consuming valve, the valve control device executes the lockout of the energy-consuming valve, and at the same time sends the lockout status of the energy-consuming valve to the polar controller, and records and sends the relevant fault information to the backend.

[0130] 2) List of fault protection functions for valve control equipment

[0131] The list of fault protection functions for valve control equipment, i.e., the third mapping relationship, is shown in Table 3.

[0132] Table 3 List of Fault Protection Functions for Valve Control Equipment

[0133]

[0134]

[0135] To enable those skilled in the art to better understand the present invention, the principles of the present invention are explained below in conjunction with the accompanying drawings:

[0136] Flexible DC transmission technology is a primary technical means to solve the grid connection problem for offshore wind power. However, when a fault occurs in the receiving-end AC grid, the wind farm energy that cannot be consumed in time will cause a rapid increase in DC voltage, threatening the safety of the converter valves and the entire system. Therefore, DC energy dissipation devices are needed to consume the energy that the system cannot transmit normally, thereby stabilizing the DC voltage and assisting the system in completing fault ride-through. A schematic diagram of wind power DC energy dissipation is shown below. Figure 5 As shown:

[0137] The flexible chopper-type DC power dissipation device adopts a direct-series IGCT configuration, representing a novel electrical topology completely different from existing solutions. This flexible chopper-type power dissipation device not only employs direct-series switching devices but also incorporates a parallel connection between the IGCT switching devices and the RCD buffer circuit, achieving dynamic voltage equalization during the power dissipation process. Furthermore, the protection configuration scheme for this flexible chopper-type DC power dissipation device is being proposed for the first time.

[0138] Modular DC power consumption device topology as follows Figure 6 As shown, modules SM-1, SM-2...SM-N are connected in series with R1, R2, L1 and L2 to form the main circuit of the flexible chopper DC power dissipation device.

[0139] Fully controlled devices can accurately control the switching on and off of modules, thereby controlling the conduction and switching off of the main circuit current. By adjusting the duty cycle, the switching on and off time of the modules can be controlled, achieving the purpose of flexible control.

[0140] R1 and R2 are called centralized DC power dissipation resistors. Their main function is to convert energy from electrical energy to heat energy, thereby suppressing the rise of DC transmission line voltage.

[0141] Reactors L1 and L2 are large reactors, whose main function is to suppress the rate of change of current (di / dt) during the turn-on and turn-off processes of the fully controlled devices.

[0142] The Rs and Cs branches form an absorption circuit that absorbs the energy during the device turn-off process, thereby limiting the voltage across the device.

[0143] The control and protection of DC power consumption devices are mainly achieved through valve-controlled devices (VCMs). These VCMs ensure the safe and stable operation of the power consumption devices under normal operating conditions and provide rapid protection in case of faults. They offer various control and protection functions, including power consumption valve control, power module capacitor voltage balancing control, device protection, redundant control switching, fault recording, and power module status monitoring. Specific functional descriptions are shown in the table below.

[0144] Table 4. Functions and descriptions of valve control devices

[0145]

[0146]

[0147]

[0148] This invention relates to a protection configuration scheme for DC energy-consuming devices based on fully controlled devices. On the one hand, it proposes a functional list of valve control devices as the carrier of protection configuration functions; on the other hand, it proposes that the valve control devices realize three protection functions for energy-consuming devices, and provides a detailed description of the protection scheme for each function.

[0149] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A protection configuration system for a DC power consumption device, characterized in that, include: System-level protection unit, power module-level protection unit, and valve control equipment fault protection unit; The system-level protection unit, power module-level protection unit, and valve-controlled equipment fault protection unit, through the valve-controlled device (VCM), realize the control and protection of the flexible chopper DC energy-consuming device. The system-level protection unit is used for system-level fault protection, including the over-limit protection subunit for the number of bypass submodules of energy-consuming devices, the overall overvoltage protection subunit for power modules, and the electrical quantity protection subunit; The power module-level protection unit is used for power module fault protection, and it is accomplished by valve control device, sub-module control board PMC and matching actuators. The valve control equipment fault protection unit is used to protect valve control equipment from faults, including protection against hardware and software faults, communication faults, and power supply faults detected by the valve control system.

2. The protection configuration system for the DC energy-consuming device according to claim 1, characterized in that, The energy consumption device bypass submodule number over-limit protection subunit is used for: When the number of faulty power modules of the energy-consuming valve exceeds the allowable number of bypasses, the over-limit protection of the bypass sub-modules of the energy-consuming device will activate and lock the energy-consuming valve.

3. The protection configuration system for the DC energy-consuming device according to claim 1, characterized in that, The power module overall overvoltage protection subunit is used for: When the capacitor voltage of the power module of the energy-consuming valve exceeds the overvoltage lockout value, the overall overvoltage lockout protection of the power module of the energy-consuming device will activate and lock the energy-consuming valve. When the capacitor voltage of the power module of the energy dissipation valve exceeds the overvoltage trip setting, the overall overvoltage trip protection of the power module of the energy dissipation device will activate, locking the energy dissipation valve and requesting a trip.

4. The protection configuration system for the DC energy-consuming device according to claim 1, characterized in that, Electrical quantity protection subunit, used for: By configuring the measurement circuit and discrimination logic of electrical quantity protection according to the principle of two out of three, overcurrent protection, current rise rate protection and current differential protection of energy-consuming devices can be realized.

5. The protection configuration system for the DC energy-consuming device according to claim 4, characterized in that, The measurement circuits and discrimination logic for electrical quantity protection are configured according to the "two out of three" principle, including: Three independent measuring devices are configured for the measuring circuit. The measuring signals are connected to the valve control device via optical fiber. The protection logic in the valve control device judges the three independent measuring signals respectively. The action result is input to the three-out-of-two judgment logic. After comprehensive judgment, it is sent to the main control CPU board of the valve control host through the high-speed communication link. The main control CPU board then blocks the energy-consuming valve through the downlink communication link, or requests the system to trip through the uplink or relay contact.

6. The protection configuration system for the DC energy-consuming device according to claim 4, characterized in that, Implement overcurrent protection for energy-consuming devices, including: The positive and negative input currents are judged separately. If the measured current at either end exceeds the overcurrent protection threshold, it is judged as a protection action and the energy consumption valve is locked. If the current continues to rise after the energy dissipation valve is locked and exceeds the trip setting value, and the duration exceeds the overcurrent protection time threshold, then an application for tripping should be immediately submitted to the upper-level control and protection equipment. The fast overcurrent protection for energy-consuming devices serves as a rapid protection against energy-consuming valve failures. The sampling rate of the positive and negative input current measurement data of the energy-consuming device is not lower than the sampling rate threshold, the total delay of the measurement circuit is not greater than the total delay threshold, and the delay of the valve-controlled fast protection circuit is less than the fast protection circuit delay threshold.

7. The protection configuration system for the DC energy-consuming device according to claim 4, characterized in that, Current rise rate protection, including: Used to quickly lock the energy-consuming valve when a serious system failure causes a rapid increase in the current of the energy-consuming device. The positive and negative incoming currents are judged separately. If the current rise rate at either end exceeds the current rise rate threshold, it is judged as a protection action and the energy consumption valve is locked. The sampling rate of the positive and negative input current measurement data of the energy-consuming device is not lower than the sampling rate threshold, the total delay of the measurement circuit is not greater than the total delay threshold, and the delay of the valve-controlled fast protection circuit is less than the fast protection circuit delay threshold.

8. The protection configuration system for the DC energy-consuming device according to claim 4, characterized in that, Differential current protection includes: Based on the measured currents at both ends of the energy-consuming device, the differential current and braking current of the energy-consuming device are calculated, and the presence of a fault is determined based on the differential relay; the formula for calculating the differential current is as follows: i d =i1+i2 Where i d i1 is the differential current; i2 is the positive input current of the energy-consuming device; i3 is the negative input current of the energy-consuming device. The formula for calculating braking current is as follows: i r =i1-i2 Where i r This is the braking current; The operating conditions for the differential relay are as follows: Where I op0 The differential starting current setting; k s I is the braking coefficient; n Rated current; When the differential relay of the differential protection for the energy-consuming device operates, it confirms the blocking of the energy-consuming valve; if the duration of the operation exceeds the differential protection time threshold, it requests a trip from the upper-level control and protection.

9. The protection configuration system for a DC energy-consuming device according to claim 1, characterized in that, Also includes: After any system-level protection action is activated, the valve control device immediately locks the energy-consuming valve, triggers fault recording, and sends SOE event information to the local human-machine interface and monitoring system.

10. The protection configuration system for a DC energy-consuming device according to claim 1, characterized in that, The electrical quantity protection subunit determines the protection configuration based on the first mapping relationship, including: Based on the first mapping relationship, the exit method is determined according to the protection settings and conditions; The first mapping relationship is an electronic spreadsheet that records the correspondence between protection settings and conditions and exit methods; Based on the protection settings and conditions, the export method is determined by consulting the aforementioned spreadsheet; The configuration of electrical quantity protection is determined based on the protection settings, conditions, and output method.

11. The protection configuration system for a DC energy-consuming device according to claim 1, characterized in that, Power module-level protection unit, specifically used for: The PMC uses an FPGA as the main control chip to control and protect the sub-modules' operating modes and detect their status. The PMC receives and processes control commands from the valve control device to control the power module's operation. The PMC detects the health status of each device in the power module, makes a fault judgment, and sends it to the valve control device. After receiving the module fault information, the valve control device issues a bypass command to the faulty power module when the number of faulty modules is less than the number of allowed bypass modules. Power module-level faults include: power device faults, self-powered power supply faults, undervoltage and overvoltage faults, bypass switch failures, board power supply faults, and downlink fiber optic communication faults.

12. The protection configuration system for a DC energy-consuming device according to claim 1, characterized in that, The power module-level protection unit determines the protection configuration based on the second mapping relationship, including: Based on the second mapping relationship, the exit method is determined according to the protection settings and conditions; The second mapping relationship is an electronic spreadsheet that records the correspondence between protection settings and conditions and export methods; Based on the protection settings and conditions, the export method is determined by consulting the aforementioned spreadsheet; The power module-level protection configuration is determined based on the protection settings, conditions, and output method.

13. The protection configuration system for a DC energy-consuming device according to claim 1, characterized in that, Valve control equipment fault protection unit, specifically used for: For valve control equipment fault protection, after the threshold is reached, the valve control device first requests the polar controller to switch the system and records the relevant fault information and sends it to the background. If the backup system is unavailable or the fault persists after switching systems, the valve controller will lock the energy-consuming valve to protect the safety of the primary equipment. At the same time, it will send the energy-consuming valve lockout status to the polar controller and record and send the relevant fault information to the background.

14. The protection configuration system for a DC energy-consuming device according to claim 1, characterized in that, The valve-controlled equipment fault protection unit determines the protection configuration based on a third mapping relationship, including: Based on the third mapping relationship, the exit method is determined according to the protection settings and conditions; The third mapping relationship is an electronic spreadsheet that records the correspondence between protection settings and conditions and exit methods; Based on the protection settings and conditions, the export method is determined by consulting the aforementioned spreadsheet; The fault protection configuration of the valve control equipment is determined based on the protection settings, conditions, and outlet method.

15. A protection configuration method for a DC energy-consuming device, characterized in that, The protection configuration system based on any one of claims 1-14 is used to control and protect the flexible chopper-type DC power consumption device.

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