Asymmetrical valve regulated overcurrent protection method and system for inhibiting discharge current of a module capacitor

Abstract

The present application relates to a kind of asymmetric valve control overcurrent protection method and system of inhibiting module capacitance discharge current, comprising the following steps: based on the establishment of electromagnetic transient simulation model of flexible direct current multi-station networking system, and determine the minimum valve control overcurrent protection setting value under rectification state not to be locked and the maximum valve control overcurrent protection setting value under inversion state not to be overrun;Based on the minimum valve control overcurrent protection setting value and the maximum valve control overcurrent protection setting value determined, determine actual valve control overcurrent protection strategy;Based on actual valve control overcurrent protection strategy, determine actual valve control overcurrent protection setting value, carry out valve control overcurrent protection.The present application utilizes the different characteristics of fault ride-through and in-station safety electrical stress of converter station under different operating states, by dynamically switching valve control overcurrent protection setting value under rectification and inversion state, the requirements of converter station to safe operation and fault ride-through are realized.Therefore, the present application can be widely applied in direct current transmission field.

Description

Technical Field

[0001] This invention relates to an asymmetric valve-controlled overcurrent protection method and system, particularly an asymmetric valve-controlled overcurrent protection method and system for suppressing the rapid discharge current of module capacitors in a flexible DC multi-station network system, belonging to the field of DC power transmission. Background Technology

[0002] Flexible DC transmission technology has become the preferred solution for large-scale transmission and distribution of clean energy due to its low voltage harmonic content and stable output frequency and voltage.

[0003] When converter valves experience line faults such as DC line grounding, DC pole-to-metal return short circuits, and bipolar short circuits, the converter station needs to be able to perform fault ride-through to prevent the power outage area from increasing. This means that the station should not be locked out or shut down during a fault. However, current converter valves have weak overcurrent capacity, and in the event of a severe fault, overcurrent can burn out power electronic devices, leading to serious accidents.

[0004] The existing solution is to set a lower valve-controlled overcurrent protection setting to ensure the safe operation of converter stations and reduce the fault ride-through capability of multi-terminal flexible DC grid projects. However, for flexible DC grid projects with more ports, as the number of converter stations connected in parallel increases, multiple converter stations feed fault current to the faulty station during line faults, posing a significant challenge to the safety of the converter stations. Continuously reducing the valve-controlled overcurrent protection setting will make DC line fault ride-through an intractable problem. Summary of the Invention

[0005] To address the aforementioned problems, the purpose of this invention is to provide an asymmetric valve-controlled overcurrent protection method and system for suppressing module capacitor discharge current. This method can effectively solve the problem that when the number of converter stations connected in parallel increases, a single fixed value for converter valve overcurrent protection cannot simultaneously ensure the safety of the converter valve within the station and DC fault ride-through.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides an asymmetric valve-controlled overcurrent protection method for suppressing module capacitor discharge current, comprising the following steps:

[0008] An electromagnetic transient simulation model was established based on a flexible DC multi-station network system, and the minimum valve-controlled overcurrent protection setting value I under rectification conditions was determined. settingmin_rec And the maximum valve-controlled overcurrent protection setting I that does not exceed limits under inverter conditions. settingmax_inv ;

[0009] Based on the determined minimum valve-controlled overcurrent protection setting I settingmin_rec and maximum valve-controlled overcurrent protection setting I settingmax_inv Determine the actual valve-controlled overcurrent protection strategy;

[0010] Based on the actual valve-controlled overcurrent protection strategy, the actual valve-controlled overcurrent protection setting value is determined, and valve-controlled overcurrent protection is implemented.

[0011] Furthermore, an electromagnetic transient simulation model is established based on the flexible DC multi-station network system, and the minimum valve-controlled overcurrent protection setting value I under rectification state without blocking is determined. settingmin_rec And the maximum valve-controlled overcurrent protection setting I that does not exceed limits under inverter conditions. settingmax_inv ,include:

[0012] Establish an electromagnetic transient simulation model for a flexible DC multi-station network system;

[0013] Simulation calculations were performed to determine the full fault location and fault time of a DC line fault under rectification conditions, and the minimum valve-controlled overcurrent protection setting I was determined to ensure that the converter valves do not experience overall lock-up during a DC line fault. settingmin_rec ;

[0014] Simulation calculations were conducted under the most demanding condition of a valve-side ground fault in the bridge arm reactor during inverter operation. Based on the maximum overcurrent capacity and fastest blocking time of the converter valve IGBT, the maximum valve-controlled overcurrent protection setting I was determined to ensure that the blocking current of the converter valve does not exceed the limit during station faults. settingmax_inv .

[0015] Furthermore, the simulation calculation of the full fault location and fault time of the DC line fault under the rectification state considers the fault types including DC line grounding fault, DC pole-to-metal return short circuit fault and bipolar short circuit fault.

[0016] Furthermore, the minimum valve-controlled overcurrent protection setting I settingmin_rec It is obtained by multiplying the maximum bridge arm current of the DC line fault obtained from simulation calculation by a preset coefficient.

[0017] Furthermore, the maximum valve-controlled overcurrent protection setting I settingmax_inv The calculation method is as follows:

[0018] First, the fastest current rise rate d is obtained based on simulation calculations. imax ;

[0019] Then, based on the maximum overcurrent capacity I of the IGBT of the converter valve... max and fastest locking time t delay The maximum value calculated by the limit theory is I. max -d imax t delay ;

[0020] Finally, the maximum value of the limit theory is multiplied by a preset coefficient to obtain the maximum valve-controlled overcurrent protection setting.

[0021] Furthermore, the determined minimum valve-controlled overcurrent protection setting I... settingmin_rec and maximum valve-controlled overcurrent protection setting I settingmax_inv Determine the actual valve-controlled overcurrent protection strategy, including: setting the minimum valve-controlled overcurrent protection setting I. settingmin_rec and maximum valve-controlled overcurrent protection setting I settingmax_inv Compare, if I settingmin_rec >I settingmax_inv Then, asymmetric valve-controlled overcurrent protection is used; if I settingmin_rec <I settingmax_inv In this case, symmetrical valve-controlled overcurrent protection is adopted.

[0022] Furthermore, the step of determining the actual valve-controlled overcurrent protection setting based on the actual valve-controlled overcurrent protection strategy and performing valve-controlled overcurrent protection includes:

[0023] When using an asymmetric valve-controlled overcurrent protection strategy, the following steps are included:

[0024] The pole control system of the flexible DC converter station determines whether the converter valve is in rectification or inversion state, and sends the rectification or inversion state signal to the valve control system of the flexible DC converter station.

[0025] When the valve control system receives a signal that the converter valve is in rectification mode, the first protection setting I is adopted. setting1 And the first protection setting is selected to ensure I setting1 >I settingmin_rec ;

[0026] When the valve control system receives a signal that the converter valve is in inverter mode, the second protection setting I is used. setting2 And the second protection setting is selected to ensure I setting2 <I settingmax_inv ;

[0027] When a symmetrical valve-controlled overcurrent protection strategy is adopted, regardless of whether the converter valve is in rectification or inversion mode, a fixed valve-controlled overcurrent protection setting I is used. setting3 And the fixed valve-controlled overcurrent protection setting I setting3 Set as I settingmin_rec <I setting3 <I settingmax_inv .

[0028] Secondly, the present invention provides an asymmetric valve-controlled overcurrent protection system for suppressing the discharge current of module capacitors, comprising:

[0029] The extreme value determination module is used to establish an electromagnetic transient simulation model based on a flexible DC multi-station network system, and to determine the minimum valve-controlled overcurrent protection setting I under rectification conditions without blocking. settingmin_rec And the maximum valve-controlled overcurrent protection setting I that does not exceed limits under inverter conditions. settingmax_inv ;

[0030] The protection strategy determination module is used to determine the minimum valve-controlled overcurrent protection setting I. settingmin_rec and maximum valve-controlled overcurrent protection setting I settingmax_inv Determine the actual valve-controlled overcurrent protection strategy;

[0031] The valve-controlled protection setting determination module is used to determine the actual valve-controlled overcurrent protection setting based on the actual valve-controlled overcurrent protection strategy, and to perform valve-controlled overcurrent protection.

[0032] Thirdly, the present invention provides a computer-readable storage medium for storing one or more programs, said one or more programs including instructions that, when executed by a computing device, cause the computing device to perform any of the methods.

[0033] Fourthly, the present invention provides a computing device comprising: one or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, and the one or more programs include instructions for performing any of the methods.

[0034] The present invention has the following advantages due to the adoption of the above technical solutions:

[0035] 1) This invention utilizes the characteristics of different fault ride-through and internal safety electrical stress of converter stations under different operating conditions. By dynamically switching the valve-controlled overcurrent protection setting value under rectification and inversion conditions, it provides an asymmetric valve-controlled overcurrent protection method to effectively address the problem of not being able to simultaneously ensure internal safety and fault ride-through caused by the increase in the number of parallel converter stations under multi-terminal flexible DC grids.

[0036] 2) The present invention improves the reliability of flexible DC power grids by dynamically switching the dynamic valve-controlled overcurrent protection setting value through the operating state.

[0037] Therefore, this invention can be widely applied in the field of DC power transmission. Attached Figure Description

[0038] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts. In the drawings:

[0039] Figure 1 This is a flowchart of the asymmetric valve-controlled overcurrent protection method provided in the embodiments of the present invention. Detailed Implementation

[0040] 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, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention are within the scope of protection of the present invention.

[0041] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0042] To address the issue that existing valve-controlled overcurrent protection setting methods in multi-terminal flexible DC grid systems struggle to balance substation safety with DC line fault ride-through, some embodiments of this invention propose an asymmetric valve-controlled overcurrent protection method to suppress module capacitor discharge current. This method leverages the varying fault ride-through and substation safety electrical stress characteristics of converter stations under different operating conditions. By dynamically switching the valve-controlled overcurrent protection setting during rectification and inversion, it achieves the converter station's requirements for safe operation and fault ride-through.

[0043] Correspondingly, in other embodiments of the present invention, an asymmetric valve-controlled overcurrent protection system, device, and medium for suppressing module capacitor discharge current are provided.

[0044] Example 1

[0045] like Figure 1 As shown, this embodiment provides an asymmetric valve-controlled overcurrent protection method for suppressing the discharge current of module capacitors, used to suppress the rapid discharge current of module capacitors in a flexible DC multi-station network system. The method includes the following steps:

[0046] 1) Based on the electromagnetic transient simulation model established by the flexible DC multi-station network system, determine the minimum valve-controlled overcurrent protection setting I under rectification state without blocking. settingmin_rec And the maximum valve-controlled overcurrent protection setting I that does not exceed limits under inverter conditions. settingmax_inv ;

[0047] 2) Based on the determined minimum valve-controlled overcurrent protection setting I settingmin_rec and maximum valve-controlled overcurrent protection setting I settingmax_inv Determine the actual valve-controlled overcurrent protection strategy;

[0048] 3) Based on the actual valve-controlled overcurrent protection strategy, determine the actual valve-controlled overcurrent protection setting value to meet the requirements of the converter station for safe operation and fault ride-through.

[0049] Preferably, step 1) above includes the following steps:

[0050] 1.1) Establish an electromagnetic transient simulation model for a flexible DC multi-station network system;

[0051] 1.2) Conduct simulation calculations of the full fault location and fault time of DC line faults under rectification conditions, and determine the minimum valve-controlled overcurrent protection setting I to ensure that the converter valves do not experience overall lock-up during DC line faults. settingmin_rec ;

[0052] 1.3) Conduct simulation calculations for the most demanding moment under a ground fault on the valve side of the bridge arm reactor in inverter mode. Based on the maximum overcurrent capacity and fastest blocking time of the converter valve IGBT, determine the maximum valve-controlled overcurrent protection setting I to ensure that the blocking current of the converter valve does not exceed the limit during station faults. settingmax_inv .

[0053] Preferably, in step 1.2) above, the simulation calculation of the full fault location and fault time of DC line fault under rectification state considers the fault types including DC line grounding fault, DC pole-to-metal return short circuit fault and bipolar short circuit fault. Under each type of fault, backup protection action needs to be further considered.

[0054] Furthermore, in step 1.2), the minimum valve-controlled overcurrent protection setting value I settingmin_rec It is calculated by multiplying the simulated maximum bridge arm current of a DC line fault by a coefficient greater than 1. In this embodiment, a coefficient of 1.1 is recommended.

[0055] Furthermore, in step 1.3), the simulation calculation of the full fault time under the valve-side grounding fault of the bridge arm reactor in inverter mode selects the most stringent fault time, that is, the time when the number of conducting modules in the bridge arm where the fault is located is the fewest. At this time, the fault point is short-circuited with the other phases of this station and other converter stations, and the fault current rises rapidly.

[0056] Furthermore, in step 1.3), the maximum valve-controlled overcurrent protection setting I... settingmax_inv The calculation method is as follows: First, the fastest current rise rate d is obtained through simulation calculation. imax Then, based on the maximum overcurrent capacity I of the IGBT of the converter valve... max and fastest locking time t delay The maximum value calculated by the limit theory is I. max -d imax t delayFinally, the maximum value of the limit theory is multiplied by a coefficient less than 1 to obtain the maximum valve-controlled overcurrent protection setting. In this embodiment, a coefficient of 0.9 is recommended.

[0057] Preferably, in step 2) above, the minimum valve-controlled overcurrent protection setting I is determined. settingmin_rec and maximum valve-controlled overcurrent protection setting I settingmax_inv Determining the actual valve-controlled overcurrent protection strategy refers to: setting the minimum valve-controlled overcurrent protection setting I... settingmin_rec and maximum valve-controlled overcurrent protection setting I settingmax_inv Compare, if I settingmin_rec >I settingmax_inv Then, asymmetric valve-controlled overcurrent protection is used; if I settingmin_rec <I settingmax_inv In this case, symmetrical valve-controlled overcurrent protection is adopted.

[0058] Preferably, in step 3) above, when an asymmetric valve-controlled overcurrent protection strategy is adopted, the following steps are included:

[0059] The pole control system of the flexible DC converter station determines whether the converter valve is in rectification or inversion state, and sends the rectification or inversion state signal to the valve control system of the flexible DC converter station.

[0060] When the valve control system receives a signal that the converter valve is in rectification mode, the first protection setting I is adopted. setting1 And the first protection setting is selected to ensure I setting1 >I settingmin_rec The maximum value is selected based on the principle that the switching valve lock-up current should not exceed the limit when there is a fault in the station under rectification conditions.

[0061] When the valve control system receives a signal that the converter valve is in inverter mode, the second protection setting I is used. setting2 And the second protection setting is selected to ensure I setting2 <I settingmax_inv The minimum value is selected based on the principle that the converter valve does not lock up as a whole under DC line fault conditions in inverter mode.

[0062] Furthermore, in step 3) above, when a symmetrical valve-controlled overcurrent protection strategy is adopted, regardless of whether the converter valve is in rectification or inversion state, a fixed valve-controlled overcurrent protection setting I is used. setting3 And the fixed valve-controlled overcurrent protection setting I setting3 Set as I settingmin_rec <I setting3 <I settingmax_inv .

[0063] Example 2

[0064] Embodiment 1 above provides an asymmetric valve-controlled overcurrent protection method for suppressing the discharge current of a module capacitor. Correspondingly, this embodiment provides an asymmetric valve-controlled overcurrent protection system for suppressing the discharge current of a module capacitor. The system provided in this embodiment can implement the asymmetric valve-controlled overcurrent protection method for suppressing the discharge current of a module capacitor as described in Embodiment 1. This system can be implemented through software, hardware, or a combination of both. For example, the system may include integrated or separate functional modules or units to perform the corresponding steps in the methods of Embodiment 1. Since the system in this embodiment is basically similar to the method embodiment, the description process in this embodiment is relatively simple. For relevant details, please refer to the description of Embodiment 1. The system embodiment provided in this embodiment is merely illustrative.

[0065] The asymmetric valve-controlled overcurrent protection system for suppressing module capacitor discharge current provided in this embodiment includes:

[0066] The extreme value determination module is used to establish an electromagnetic transient simulation model based on a flexible DC multi-station network system, and to determine the minimum valve-controlled overcurrent protection setting I under rectification conditions without blocking. settingmin_rec And the maximum valve-controlled overcurrent protection setting I that does not exceed limits under inverter conditions. settingmax_inv ;

[0067] The protection strategy determination module is used to determine the minimum valve-controlled overcurrent protection setting I. settingmin_rec and maximum valve-controlled overcurrent protection setting I settingmax_inv Determine the actual valve-controlled overcurrent protection strategy;

[0068] The valve-controlled protection setting determination module is used to determine the actual valve-controlled overcurrent protection setting based on the actual valve-controlled overcurrent protection strategy, so as to meet the requirements of the converter station for safe operation and fault ride-through.

[0069] Example 3

[0070] This embodiment provides a processing device corresponding to the asymmetric valve-controlled overcurrent protection method for suppressing the discharge current of the module capacitor provided in Embodiment 1. The processing device can be a processing device for the client, such as a mobile phone, laptop, tablet computer, desktop computer, etc., to execute the method of Embodiment 1.

[0071] The processing device includes a processor, a memory, a communication interface, and a bus. The processor, memory, and communication interface are connected via the bus to communicate with each other. The memory stores a computer program that can run on the processor. When the processor runs the computer program, it executes the asymmetric valve-controlled overcurrent protection method for suppressing the discharge current of the module capacitor provided in Embodiment 1.

[0072] In some embodiments, the memory may be high-speed random access memory (RAM), and may also include non-volatile memory, such as at least one disk storage device.

[0073] In other embodiments, the processor can be a general-purpose processor of various types, such as a central processing unit (CPU) or a digital signal processor (DSP), and is not limited thereto.

[0074] Example 4

[0075] The asymmetric valve-controlled overcurrent protection method for suppressing the discharge current of the module capacitor in Embodiment 1 can be specifically implemented as a computer program product. The computer program product may include a computer-readable storage medium on which computer-readable program instructions for executing the asymmetric valve-controlled overcurrent protection method for suppressing the discharge current of the module capacitor as described in Embodiment 1 are loaded.

[0076] A computer-readable storage medium can be a tangible device that holds and stores instructions for use by an instruction execution device. A computer-readable storage medium can be, for example, but not limited to, an electrical storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any combination thereof.

[0077] 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 it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. An asymmetric valve-controlled overcurrent protection method for suppressing module capacitor discharge current, characterized in that... Includes the following steps: An electromagnetic transient simulation model was established based on a flexible DC multi-station network system, and the minimum valve-controlled overcurrent protection setting value without blocking was determined under rectification conditions. I settingmin_rec And the maximum valve-controlled overcurrent protection setting that does not exceed limits under inverter conditions. I settingmax_inv ; Based on the determined minimum valve-controlled overcurrent protection setting I settingmin_rec and maximum valve-controlled overcurrent protection setting I settingmax_inv Determine the actual valve-controlled overcurrent protection strategy; Based on the actual valve-controlled overcurrent protection strategy, the actual valve-controlled overcurrent protection setting value is determined, and valve-controlled overcurrent protection is implemented. The determined minimum valve-controlled overcurrent protection setting value I settingmin_rec and maximum valve-controlled overcurrent protection setting I settingmax_inv Determine the actual valve-controlled overcurrent protection strategy, including: setting the minimum valve-controlled overcurrent protection setting value. I settingmin_rec and maximum valve-controlled overcurrent protection setting I settingmax_inv If a comparison is made, I settingmin_rec > I settingmax_inv Then, asymmetric valve-controlled overcurrent protection is used; if I settingmin_rec < I settingmax_inv In this case, symmetrical valve-controlled overcurrent protection is adopted; The process of determining the actual valve-controlled overcurrent protection setting based on the actual valve-controlled overcurrent protection strategy and performing valve-controlled overcurrent protection includes: When using an asymmetric valve-controlled overcurrent protection strategy, the following steps are included: The pole control system of the flexible DC converter station determines whether the converter valve is in rectification or inversion state, and sends the rectification or inversion state signal to the valve control system of the flexible DC converter station. When the valve control system receives a signal that the converter valve is in rectification mode, the first protection setting is adopted. I setting1 And the selection of the first protection setting ensures I setting1 > I settingmin_rec ; When the valve control system receives a signal that the converter valve is in inverter mode, the second protection setting is used. I setting2 And the selection of the second protection setting ensures I setting2 < I settingmax_inv ; When a symmetrical valve-controlled overcurrent protection strategy is adopted, regardless of whether the converter valve is in rectification or inversion mode, a fixed valve-controlled overcurrent protection setting is used. I setting3 And the fixed valve-controlled overcurrent protection setting I setting3 Set as I settingmin_rec < I setting3 < I settingmax_inv .

2. The asymmetric valve-controlled overcurrent protection method for suppressing module capacitor discharge current as described in claim 1, characterized in that, An electromagnetic transient simulation model was established based on the flexible DC multi-station network system, and the minimum valve-controlled overcurrent protection setting value without blocking under rectification conditions was determined. I settingmin_rec And the maximum valve-controlled overcurrent protection setting that does not exceed limits under inverter conditions. I settingmax_inv ,include: Establish an electromagnetic transient simulation model for a flexible DC multi-station network system; Simulation calculations were conducted to determine the full fault location and fault time of a DC line fault under rectification conditions, and the minimum valve-controlled overcurrent protection setting value was determined to ensure that the converter valve does not experience overall lock-up during a DC line fault. I settingmin_rec ; Simulation calculations were conducted under the most demanding condition of a valve-side ground fault in the bridge arm reactor during inverter operation. Based on the maximum overcurrent capacity and fastest blocking time of the converter valve IGBT, the maximum valve-controlled overcurrent protection setting value was determined to ensure that the blocking current of the converter valve does not exceed the limit during station faults. I settingmax_inv .

3. The asymmetric valve-controlled overcurrent protection method for suppressing module capacitor discharge current as described in claim 2, characterized in that, The simulation calculation of the full fault location and fault time of DC line faults under the rectification state considers the fault types including DC line grounding faults, DC pole-to-metal return short circuit faults, and bipolar short circuit faults.

4. The asymmetric valve-controlled overcurrent protection method for suppressing module capacitor discharge current as described in claim 2, characterized in that, The minimum valve-controlled overcurrent protection setting value I settingmin_rec It is obtained by multiplying the maximum bridge arm current of the DC line fault obtained from simulation calculation by a preset coefficient.

5. The asymmetric valve-controlled overcurrent protection method for suppressing module capacitor discharge current as described in claim 2, characterized in that, The maximum valve-controlled overcurrent protection setting value I settingmax_inv The calculation method is as follows: First, the fastest current rise rate is obtained based on simulation calculations. d imax ; Then, based on the maximum overcurrent capacity of the IGBT in the converter valve. I max and fastest locking time t delay The calculated maximum value of the limit theory is I max - d imax · t delay ; Finally, the maximum value of the limit theory is multiplied by a preset coefficient to obtain the maximum valve-controlled overcurrent protection setting.

6. An asymmetric valve-controlled overcurrent protection system for suppressing module capacitor discharge current, characterized in that, include: The extreme value determination module is used to establish an electromagnetic transient simulation model based on a flexible DC multi-station network system, and to determine the minimum valve-controlled overcurrent protection setting value that is not blocked under rectification conditions. I settingmin_rec And the maximum valve-controlled overcurrent protection setting that does not exceed limits under inverter conditions. I settingmax_inv ; The protection strategy determination module is used to determine the minimum valve-controlled overcurrent protection setting. I settingmin_rec and maximum valve-controlled overcurrent protection setting I settingmax_inv Determine the actual valve-controlled overcurrent protection strategy; The valve-controlled protection setting determination module is used to determine the actual valve-controlled overcurrent protection setting based on the actual valve-controlled overcurrent protection strategy, and to perform valve-controlled overcurrent protection. The determined minimum valve-controlled overcurrent protection setting value I settingmin_rec and maximum valve-controlled overcurrent protection setting I settingmax_inv Determine the actual valve-controlled overcurrent protection strategy, including: setting the minimum valve-controlled overcurrent protection setting value. I settingmin_rec and maximum valve-controlled overcurrent protection setting I settingmax_inv If a comparison is made, I settingmin_rec > I settingmax_inv Then, asymmetric valve-controlled overcurrent protection is used; if I settingmin_rec < I settingmax_inv In this case, symmetrical valve-controlled overcurrent protection is adopted; The process of determining the actual valve-controlled overcurrent protection setting based on the actual valve-controlled overcurrent protection strategy and performing valve-controlled overcurrent protection includes: When using an asymmetric valve-controlled overcurrent protection strategy, the following steps are included: The pole control system of the flexible DC converter station determines whether the converter valve is in rectification or inversion state, and sends the rectification or inversion state signal to the valve control system of the flexible DC converter station. When the valve control system receives a signal that the converter valve is in rectification mode, the first protection setting is adopted. I setting1 And the selection of the first protection setting ensures I setting1 > I settingmin_rec ; When the valve control system receives a signal that the converter valve is in inverter mode, the second protection setting is used. I setting2 And the selection of the second protection setting ensures I setting2 < I settingmax_inv ; When a symmetrical valve-controlled overcurrent protection strategy is adopted, regardless of whether the converter valve is in rectification or inversion mode, a fixed valve-controlled overcurrent protection setting is used. I setting3 And the fixed valve-controlled overcurrent protection setting I setting3 Set as I settingmin_rec < I setting3 < I settingmax_inv .

7. A computer-readable storage medium for storing one or more programs, characterized in that, The one or more programs include instructions that, when executed by a computing device, cause the computing device to perform any of the methods described in claims 1 to 5.

8. A computing device, characterized in that, include: One or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the one or more programs including instructions for performing any of the methods described in claims 1 to 5.

Images