New energy power station grounding protection system, method, electronic device, and storage medium

Abstract

The present application provides a new energy power station grounding protection system, a method, an electronic device, and a storage medium, relating to the field of new energy power system protection technology. The system comprises: a grounding protection apparatus, as well as a grounding transformer neutral point device, a first current transformer and a voltage transformer; the voltage transformer is used to detect the voltage of a bus; the first current transformer is used to detect the current of an outgoing line; the neutral point of the grounding transformer is grounded by means of an isolation switch, a circuit breaker and a resistor in sequence; and the grounding protection apparatus is used to collect the voltage of the bus and the current of the outgoing line, perform amplitude phase comparison, collect a closed / open state of the circuit breaker, determine whether a power grid side connected to the outgoing line has a grounding fault, and generate a corresponding opening / closing instruction, so as to control the circuit breaker, on the basis of the opening / closing instruction, to perform a corresponding opening / closing operation. The described means do not require additional devices such as an isolation transformer or a secondary screen cabinet, and thus reduce manpower and device resource consumption.

Description

New energy power station grounding protection system, method, electronic equipment and storage medium

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on August 16, 2023, with application number 202311028247.X and application name “New Energy Power Station Grounding Protection System, Method, Electronic Device and Storage Medium”, all contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the technical field of new energy power system protection, and in particular to a new energy power station grounding protection system, method, electronic equipment and storage medium. Background Art

[0003] With the development of new energy, new energy measures such as carbon peak and carbon neutrality have gradually been implemented. For example, small-scale new energy power systems such as distributed wind power choose to connect to the nearest distribution network for local consumption, saving transmission investment and losses.

[0004] The grounding methods of power systems are generally divided into effective grounding and ineffective grounding. Ineffective grounding methods can be divided into neutral point ungrounded method, neutral point low resistance grounding method, neutral point high resistance grounding method and neutral point resonant grounding method. Among them, the ungrounded method is suitable for 35kV distribution networks with single-phase grounding fault capacitance current less than 10A and mainly composed of overhead lines. There are many 35kV cables in new energy power stations, and the capacitance current is large. Therefore, low-resistance grounding is often used to achieve the requirement of quickly clearing ground faults. However, the direct connection of new energy power stations with low-resistance grounding to the 35kV distribution network with ungrounding method brings about the problem of inconsistent system neutral point grounding methods.

[0005] To solve this problem, the existing technology needs to add an isolation transformer with a voltage level of 35 / 35kV and a connection group of YNd, as well as supporting secondary panels such as main transformer protection and main transformer measurement and control. However, this has technical problems such as high cost and increased consumption of manpower and equipment resources.

[0006] Summary of the Invention

[0007] The present application provides a new energy power station grounding protection system, method, electronic equipment and storage medium to solve the problem in the prior art that the grounding methods of new energy power stations and distribution networks are inconsistent, requiring the addition of isolation transformers and secondary panels and other equipment, which in turn leads to increased consumption of manpower and equipment resources.

[0008] According to a first aspect of the present application, there is provided a new energy power station grounding protection system, comprising: a grounding neutral point transformer device, a first current transformer, a voltage transformer, and a grounding protection device;

[0009] The new energy power station includes several lines, wherein the several lines include: a busbar, a transmission line, and multiple branches; the branches and the transmission line are respectively connected to the busbar, the busbar is provided with the voltage transformer, and the transmission line is provided with the first current transformer; the voltage transformer and the first current transformer are respectively connected to the grounding protection device;

[0010] The voltage transformer is used to detect the voltage of the busbar; the first current transformer is used to detect the current of the output line;

[0011] The multiple branches include a grounding transformer branch provided with a grounding transformer and the grounding-to-neutral point device; the grounding-to-neutral point device includes an isolating switch, a circuit breaker, and a resistor connected in sequence; the high-voltage side of the grounding transformer is connected to the busbar, and the neutral point of the grounding transformer is grounded through the isolating switch, the circuit breaker, and the resistor in sequence;

[0012] The grounding protection device is used to collect the voltage of the busbar and the current of the outgoing line, perform amplitude and phase comparison, collect the closing / opening state of the circuit breaker, and determine whether a grounding fault occurs on the grid side to which the outgoing line is connected, thereby obtaining a first determination result; generate a corresponding opening / closing instruction based on the first determination result, and issue the opening / closing instruction to the circuit breaker;

[0013] The circuit breaker performs corresponding opening / closing operations according to the opening / closing instruction.

[0014] Optionally, the ground protection device includes: a processing module, and an analog input acquisition module, a switch input acquisition module and an output module respectively connected to the processing module;

[0015] The analog input acquisition module includes a first interface of the analog input acquisition module and a tenth interface of the analog input acquisition module; the first interface of the analog input acquisition module is connected to the first current transformer; the tenth interface of the analog input acquisition module is connected to the voltage transformer;

[0016] The switch value input acquisition module includes a first interface of the switch value input acquisition module, the first interface of the switch value input acquisition module is connected to the circuit breaker, and is used to acquire the closing / opening state of the circuit breaker;

[0017] The output module includes a fifth interface of the output module and a sixth interface of the output module, wherein the fifth interface of the output module is connected to the tripping circuit of the circuit breaker for outputting an opening instruction; the sixth interface of the output module is connected to the closing circuit of the circuit breaker for outputting a closing instruction.

[0018] Optionally, the processing module includes a first processing circuit and a second processing circuit connected in parallel, and the output module includes an output relay and a start relay; wherein the output relay includes a first output relay, a second output relay, a third output relay, a fourth output relay, a fifth output relay and a sixth output relay; the fifth output relay is the fifth interface of the output module; and the sixth output relay is the sixth interface of the output module;

[0019] The first processing circuit includes a first analog-to-digital conversion module and a first processor connected in sequence, and the second processing circuit includes a second analog-to-digital conversion module and a second processor connected in sequence;

[0020] The first processor is connected to the first outlet relay, the second outlet relay, the third outlet relay, the fourth outlet relay, the fifth outlet relay and the sixth outlet relay respectively; the second processor is connected to the start relay;

[0021] The start relay controls whether the positive power supply of the output relay is open.

[0022] Optionally, the multiple branches further include: a collector line and an SVG line; a second current transformer is provided on the collector line, and a third current transformer is provided on the SVG line; a fourth current transformer is provided on the grounding transformer branch between the grounding transformer and the busbar;

[0023] The second current transformer, the third current transformer and the fourth current transformer are used to detect the current of the collector line, the current of the SVG line and the current of the grounding transformer branch respectively;

[0024] The grounding protection device performs a threshold comparison on the voltage of the busbar when the circuit breaker is in the open state. If the voltage of the busbar is greater than or equal to the preset threshold, the device performs calculations and performs amplitude and phase comparisons on the voltage of the busbar, the current of the outgoing line, the current of the collector line, the current of the SVG line, and the current of the grounding transformer branch to determine whether a grounding fault has occurred on the busbar, thereby obtaining a second judgment result.

[0025] The grounding protection device performs a threshold comparison on the voltage of the busbar when the circuit breaker is in the open state. If the voltage of the busbar is greater than or equal to the preset threshold, the voltage of the busbar and the current of the collector line are calculated and compared in amplitude and phase to determine whether a ground fault occurs in the collector line, thereby obtaining a third judgment result.

[0026] The grounding protection device performs a threshold comparison on the voltage of the busbar when the circuit breaker is in the open state. If the voltage of the busbar is greater than or equal to the preset threshold, the device performs an operation on the voltage of the busbar and the current of the SVG line, and performs an amplitude and phase comparison to determine whether a ground fault occurs in the SVG line, thereby obtaining a fourth determination result.

[0027] When the circuit breaker is in the open state, the grounding protection device performs a threshold comparison on the voltage of the busbar. If the voltage of the busbar is greater than or equal to the preset threshold, the voltage of the busbar and the current of the grounding transformer are calculated and the amplitude and phase are compared to determine whether a grounding fault occurs in the grounding transformer, thereby obtaining a fifth judgment result.

[0028] Optionally, the analog input acquisition module further includes: a second interface of the analog input acquisition module, a third interface of the analog input acquisition module, and a fourth interface of the analog input acquisition module, wherein:

[0029] The second interface of the analog input acquisition module is connected to the second current transformer;

[0030] The third interface of the analog input acquisition module is connected to the third current transformer;

[0031] The fourth interface of the analog input acquisition module is connected to the fourth current transformer.

[0032] Optionally, the output module further includes a first interface of the output module, a second interface of the output module, a third interface of the output module, and a fourth interface of the output module; wherein the first interface of the output module is a first output relay; the second interface of the output module is a second output relay; the third interface of the output module is a third output relay; and the fourth interface of the output module is a fourth output relay;

[0033] The output line is further provided with a first circuit breaker located between the first current transformer and the busbar; the trip circuit of the first circuit breaker is connected to the first interface of the output module;

[0034] The collector circuit is further provided with a second circuit breaker located between the second current transformer and the busbar; the trip circuit of the second circuit breaker is connected to the second interface of the output module;

[0035] The SVG line is further provided with a third circuit breaker located between the third current transformer and the busbar; the trip circuit of the third circuit breaker is connected to the third interface of the output module;

[0036] The grounding transformer branch is further provided with a fourth circuit breaker located between the fourth current transformer and the busbar; the tripping circuit of the fourth circuit breaker is connected to the fourth interface of the output module;

[0037] the processing module being configured to, when the second judgment result is the bus fault, send a protection trip signal to the first circuit breaker, the second circuit breaker, the third circuit breaker, and the fourth circuit breaker respectively through the first interface of the output module, the second interface of the output module, the third interface of the output module, and the fourth interface of the output module;

[0038] The processing module is further configured to send a protection trip signal to the second circuit breaker through the second interface of the output module when the third judgment result is that the collector line is faulty;

[0039] The processing module is further configured to send a protection trip signal to the third circuit breaker via the third interface of the output module when the fourth judgment result is that the SVG line is faulty;

[0040] The processing module is further configured to send a protection tripping signal to the fourth circuit breaker through the fourth interface of the output module when the fifth judgment result is that the grounding transformer branch is faulty.

[0041] Optionally, the system further comprises a fifth current transformer arranged between the resistor and the ground, and a temperature-controlled switch in the resistor chamber where the resistor is located;

[0042] The analog input acquisition module further includes a fifth interface of the analog input acquisition module, and the fifth interface of the analog input acquisition module is connected to the fifth current transformer;

[0043] The fifth current transformer is used to detect the current of the resistor;

[0044] The second interface of the switch input acquisition module is connected to the temperature control switch, and is used to acquire the state of the temperature control switch;

[0045] The processing module is used to calculate the accumulated heat of the resistor based on the current of the resistor when the temperature-controlled switch is in a closed state. When the accumulated heat of the resistor is greater than or equal to a preset heat threshold, the processing module sends a tripping command to the circuit breaker through the fifth interface of the output module (i.e., instantaneously acts on the circuit breaker DL to switch it to the tripping state), and after a delay of a preset time period, sends a protection tripping signal to the fourth circuit breaker through the fourth interface of the output module.

[0046] According to a second aspect of the present application, a grounding protection method for a new energy power station is provided, which is applied to the grounding protection system of the new energy power station, comprising:

[0047] The voltage transformer is used to detect the voltage of the busbar and send the voltage of the busbar to the grounding protection device. The first current transformer is used to detect the current of the outgoing line and send the current of the outgoing line to the grounding protection device.

[0048] The grounding protection device is used to collect the voltage of the busbar and the current of the outgoing line, perform amplitude and phase comparison, collect the closing / opening state of the circuit breaker, and determine whether a grounding fault occurs on the grid side to which the outgoing line is connected, thereby obtaining a first determination result; generate a corresponding opening / closing instruction based on the first determination result, and issue the opening / closing instruction to the circuit breaker;

[0049] The circuit breaker performs corresponding opening / closing operations according to the opening / closing instruction.

[0050] According to a third aspect of the present application, there is provided an electronic device, comprising: at least one processor and a memory;

[0051] The memory stores computer-executable instructions;

[0052] The at least one processor executes the computer-executable instructions stored in the memory, so that the at least one processor executes the new energy power station grounding protection method as described in the second aspect above.

[0053] According to a fourth aspect of the present application, a computer-readable storage medium is provided, in which computer-executable instructions are stored. When the computer-executable instructions are executed by a processor, they are used to implement the new energy power station grounding protection method as described in the second aspect above.

[0054] According to a fifth aspect of the present application, a computer program product is provided, comprising a computer program, which, when executed by a processor, implements the grounding protection method for the new energy power station described in the second aspect.

[0055] The present application provides a grounding protection system for a new energy power station, comprising: a grounding transformer neutral point device, a first current transformer, a voltage transformer and a grounding protection device; wherein the new energy power station comprises several lines, the several lines comprising: a busbar, a transmission line and a plurality of branches; the branches and the transmission line are respectively connected to the busbar, a voltage transformer is provided on the busbar, and a first current transformer is provided on the transmission line; the voltage transformer and the first current transformer are respectively connected to the grounding protection device; the voltage transformer is used to detect the voltage of the busbar; the first current transformer is used to detect the current of the transmission line; the plurality of branches comprise a grounding transformer and a grounding transformer; A grounding transformer branch of a neutral point device; the grounding transformer neutral point device includes a disconnector, a circuit breaker, and a resistor connected in sequence; the high-voltage side of the grounding transformer is connected to the busbar, and the neutral point of the grounding transformer is grounded in sequence through the disconnector, the circuit breaker, and the resistor; the grounding protection device is used to collect the voltage of the busbar and the current of the transmission line, perform amplitude and phase comparison, collect the closing / opening status of the circuit breaker, and determine whether a grounding fault occurs on the grid side connected to the transmission line, thereby obtaining a first judgment result; a corresponding opening / closing instruction is generated based on the first judgment result, and an opening / closing instruction is issued to the circuit breaker; the circuit breaker performs the corresponding opening / closing operation based on the opening / closing instruction.

[0056] This application is based on the connection of the branch line and the transmission line to the busbar of the new energy power station. By controlling the circuit breaker in the grounding transformer neutral point device to perform closing / opening operations through the grounding protection device, it can realize the control of whether the neutral point of the grounding transformer on the grounding transformer branch line where the circuit breaker is located is grounded, that is, the grounding protection system is switched between the resistance grounding mode and the ungrounded mode. Therefore, the new energy power station grounding protection system provided by this application can have the advantages of both the ungrounded mode and the low-resistance grounding mode, which not only meets the requirements of the distribution network to operate with a ground fault for 1 to 2 hours in an ungrounded mode and ensure power supply continuity, but also meets the requirements of the new energy power station to quickly cut off the ground fault. In addition, the system is a neutral point adaptive grounding system for the new energy power station directly connected to the distribution network. There is no need to add new isolation transformers, secondary panels and other equipment, which can save manpower and equipment resources.

[0057] It should be understood that the content described in this section is not intended to identify the key or important features of the embodiments of the present application, nor is it intended to limit the scope of the present application. Other features of the present application will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0059] FIG1 is a schematic structural diagram of a grounding protection system for a new energy power station provided in an embodiment of the present application;

[0060] FIG2 is a schematic structural diagram of another new energy power station grounding protection system provided in an embodiment of the present application;

[0061] FIG3 is a schematic structural diagram of a ground protection device provided in an embodiment of the present application;

[0062] FIG4 is a schematic diagram of another result of a grounding protection system for a new energy power station provided in an embodiment of the present application;

[0063] FIG5 is a schematic diagram of a grounding transformer and a neutral point device of a new energy power station provided by an embodiment of the present application;

[0064] FIG6 is a flow chart of a grounding protection method for a new energy power station according to an embodiment of the present application;

[0065] FIG7 is a schematic structural diagram of an electronic device provided in an embodiment of the present application.

[0066] The above drawings illustrate specific embodiments of the present application, which will be described in more detail below. These drawings and the textual description are not intended to limit the scope of the present application in any way, but rather to illustrate the concepts of the present application to those skilled in the art by reference to specific embodiments. DETAILED DESCRIPTION

[0067] Exemplary embodiments are described in detail herein, with examples illustrated in the accompanying drawings. When the following description refers to the drawings, identical numerals in different drawings represent identical or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all embodiments consistent with this application.

[0068] Power system grounding methods are generally categorized as effective grounding and ineffective grounding. Ineffective grounding methods can be further divided into ungrounded neutral, low-resistance grounding, high-resistance grounding, and resonant grounding. The ungrounded method is suitable for single-phase ground faults with a capacitive current less than 10A. In 35kV distribution networks, which primarily rely on overhead lines, the transient single-phase ground fault rate is 60% to 70%, and it is desirable not to cause a tripping event due to a transient ground fault. Its advantages include: single-phase ground faults with a capacitive current less than 10A, self-extinguishing arcs at the fault point, and self-recovery of insulation at the fault point after arc extinguishment. Single-phase grounding does not disrupt system symmetry, allowing operation with a fault for one to two hours, ensuring power supply continuity. Furthermore, this ungrounded method minimizes communication interference and is suitable for locations with numerous network points, a wide coverage area, and complex user base, significantly improving power supply reliability.

[0069] However, there are many 35kV cables in new energy power stations, and the capacitive current is large, so low-resistance grounding is often used to achieve the requirement of quickly cutting off ground faults.

[0070] However, when a new energy power station with low-resistance grounding is directly connected to an ungrounded 35kV distribution network, this leads to inconsistent neutral point grounding methods. To address this issue, existing technologies require the use of a 35 / 35kV isolation transformer with a YNd connection group, along with supporting secondary panels for main transformer protection and main transformer measurement and control. This leads to high costs and increased labor and equipment resources.

[0071] In order to solve the above technical problems, the overall inventive concept of this application is how to provide a new energy power station grounding protection system applied in the field of new energy power system protection, which is used to construct a new energy power station grounding protection system that has the advantages of both ungrounded and low-resistance grounding methods and does not require the addition of new isolation transformers and secondary panel cabinets and other equipment.

[0072] The following specific embodiments describe in detail the technical solution of the present application and how the technical solution of the present application solves the above-mentioned technical problems. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0073] Example 1:

[0074] FIG1 is a schematic diagram of a grounding protection system for a new energy power station according to an embodiment of the present application. As shown in FIG1 , a grounding protection system for a new energy power station includes: a grounding neutral point transformer 10 , a first current transformer CT1 , a voltage transformer PT and a grounding protection device 20 .

[0075] Among them, the new energy power station includes several lines, which include: a busbar L1, a transmission line L2 and multiple branches L3; the branch L3 and the transmission line L2 are respectively connected to the busbar L1, a voltage transformer PT is provided on the busbar L1, and a first current transformer CT1 is provided on the transmission line L2; the voltage transformer PT and the first current transformer CT1 are respectively connected to the grounding protection device 20.

[0076] In this embodiment of the present application, busbar L1 may refer to a 35kV busbar, one side of the transmission line L2 is connected to busbar L1, and the other side of the transmission line L2 is connected to a 35kV distribution network, or to a distribution network of other voltage values. This embodiment of the present application does not specifically limit the specific voltage value of the access distribution network.

[0077] The voltage transformer PT is used to detect the voltage of the busbar L1; the first current transformer CT1 is used to detect the current of the output line L2.

[0078] It should be understood that the voltage of busbar L1 is the open-delta voltage of the 35kV busbar detected by the voltage transformer PT, also known as the 35kV busbar zero-sequence voltage, which can be denoted as 3U0. Furthermore, the outgoing line L2 can also be referred to as the outgoing line, the 35kV outgoing line, etc. The first current transformer CT1 is a zero-sequence current transformer on the 35kV outgoing line. The current of the outgoing line L2 detected by it, also known as the outgoing line zero-sequence current, can be denoted as 3I01.

[0079] Multiple branches L3 include a grounding transformer branch L31 equipped with a grounding transformer T and a grounding neutral point device 10; the grounding neutral point device 10 includes an isolating switch GL, a circuit breaker DL and a resistor R connected in sequence; the high-voltage side of the grounding transformer T is connected to the busbar, and the neutral point of the grounding transformer T is grounded through the isolating switch GL, the circuit breaker DL and the resistor R in sequence.

[0080] In the embodiment of the present application, the grounding transformer T may refer to a grounding transformer with a connection group of ZNyn type and 35kV. The grounding transformer T also serves as a station transformer, or is called a grounding transformer and station transformer. In the ZNyn type, Z indicates that the primary winding is Z-type connected, y indicates that the secondary winding is star-connected, and N and n indicate the lead-out neutral line. In addition, the above-mentioned isolating switch GL may also be called an isolating knife switch. The above-mentioned circuit breaker DL may be understood as a grounding transformer neutral point circuit breaker, or as a 35kV grounding transformer neutral point circuit breaker. The type of the circuit breaker DL may be a vacuum circuit breaker, or may refer to other types of circuit breakers, and the embodiment of the present application does not make any specific restrictions on this. The resistor R is a low resistor, or is called the neutral point resistor of the 35kV grounding transformer, and the embodiment of the present application does not make any specific restrictions on its resistance value.

[0081] The grounding protection device 20 is used to collect the voltage of the busbar L1 and the current of the transmission line L2, perform amplitude and phase comparison, collect the closing / opening status of the circuit breaker DL, and judge whether a grounding fault occurs on the grid side connected to the transmission line L2, and obtain a first judgment result; generate a corresponding opening / closing instruction based on the first judgment result, and issue an opening / closing instruction to the circuit breaker DL.

[0082] In an embodiment of the present application, after the grounding protection device 20 collects the voltage of the bus L1, it can perform a threshold comparison on the voltage of the bus L1, where the preset threshold is Uset. The threshold comparison can be performed by a processor in the grounding protection device 20, and the calculation and amplitude phase comparison can be performed by another processor in the grounding protection device 20. In addition, the embodiment of the present application does not specifically limit the structure of the grounding protection device 20.

[0083] The circuit breaker DL performs corresponding opening / closing operations according to the opening / closing instructions.

[0084] Based on the 35kV busbar provided by the new energy power station, this embodiment of the application uses a ZNyn grounding transformer to form a zero-sequence impedance network in the event of a ground fault. The ground protection device 20 controls the circuit breaker DL based on a judgment, switching the ground protection system between low-resistance grounding mode and ungrounded mode, thereby controlling the zero-sequence impedance network during a ground fault.

[0085] In the embodiment of the present application, the ground fault type includes a ground fault on the grid side connected to the transmission line L2 (or called an out-of-zone single-phase ground fault). The ground protection device 20 can determine whether this type of fault occurs based on the determination conditions of the ground fault on the grid side connected to the transmission line L2. The determination conditions of the ground fault on the grid side connected to the transmission line L2 are: 35kV busbar zero sequence voltage 3U0≥Uset, 3I01≥preset current value Iset.

[0086] In a specific example, the grounding protection device 20 can first perform a threshold comparison on the 35kV bus zero-sequence voltage 3U0, and then determine whether to perform a judgment on the other two conditions based on the threshold comparison result. That is, if 3U0≤Uset, it is not necessary to perform a judgment on the other two conditions, and the first judgment result is: no grounding fault occurs on the grid side connected to the transmission line L2, and no grounding fault occurs in the new energy power station (that is, there is no grounding fault in the 35kV system). If 3U0≥Uset, the grounding protection device 20 can continue to be used to detect and compare the phases of the 35kV bus zero-sequence voltage and the transmission line zero-sequence current 3I01 to obtain a phase comparison result. If the phase comparison result and the transmission line zero-sequence current 3I01 both meet the determination conditions of a ground fault on the grid side to which the transmission line L2 is connected, the first determination result is that a ground fault occurs on the grid side to which the transmission line L2 is connected.

[0087] For the grid-side ground fault connected to outgoing line L2, the corresponding control strategy is as follows: ground protection device 20 issues a trip command to circuit breaker DL, causing circuit breaker DL to execute the trip command and enter the tripped state (i.e., tripping circuit breaker DL). This in turn switches the ground protection system of the new energy power station from a low-resistance grounding mode to an ungrounded mode, effectively preventing damage to the neutral point resistor of the 35kV grounding transformer due to overheating caused by long-term current flow. It should be understood that the trip command is also called a trip signal.

[0088] Different types of ground faults have different determination conditions and correspond to different control strategies. Example 1 describes in detail the determination conditions and control strategy for the ground fault type of the grid-side ground fault connected to the outgoing transmission line L2. Detailed descriptions of other ground fault types, their determination conditions, and control strategies are provided in Example 3 below and are not repeated here.

[0089] In addition, embodiments of the present application can determine whether a fault has been recovered based on the fault recovery criteria, which are: the circuit breaker DL is in the open state and 3U0 ≤ Uset. The corresponding control strategy for fault recovery is: after a delay t, the grounding protection device 20 issues a closing command to the circuit breaker DL, causing the circuit breaker DL to execute the closing command and switch from the open state to the closed state.

[0090] In the embodiment of the present application, the closing instruction is also called a closing signal.

[0091] The embodiment of the present application uses a grounding protection system for a new energy power station connected to a 35kV distribution network. On the basis of the branch L3 and the outgoing line L2 being connected to the busbar L1, the grounding protection device 20 controls the circuit breaker DL in the grounding transformer neutral point device 10 to perform closing / opening operations, thereby controlling whether the neutral point of the grounding transformer T on the grounding transformer branch L31 where the circuit breaker DL is located is grounded, that is, switching the grounding protection system of the new energy power station between the resistance grounding mode and the ungrounded mode. Therefore, the grounding protection system for the new energy power station provided by the present application can combine the advantages of the ungrounded mode and the low-resistance grounding mode, meeting the requirements of the distribution network to operate with a ground fault for 1 to 2 hours in an ungrounded mode and ensure power supply continuity, and meeting the requirements of the new energy power station to quickly cut off the ground fault. In addition, the system is a neutral point adaptive grounding system for the new energy power station directly connected to the distribution network. There is no need to add equipment such as isolation transformers and secondary panels, which can save the capital investment in isolation transformers and supporting protection and measurement and control devices, as well as the consumption of manpower and equipment resources.

[0092] Based on the above embodiments, the technical solution of the present application is described in more detail below in combination with several specific embodiments.

[0093] Example 2:

[0094] Figure 2 is a schematic diagram of the structure of another grounding protection system for a new energy power station provided in an embodiment of the present application. The embodiment of the present application refines the structure of the grounding protection device in the grounding protection system for a new energy power station.

[0095] As shown in FIG2 , the ground protection device 20 includes: a processing module U, and an analog input acquisition module AI, a switch input acquisition module BI, and an output module BO respectively connected to the processing module U.

[0096] It should be understood that the analog input acquisition module AI may be called AI plug-in, the switch input acquisition module BI may be called BI plug-in, and the output module BO may be called BO plug-in, switch output module.

[0097] Among them, the analog input acquisition module AI includes the first interface AI01 of the analog input acquisition module and the tenth interface AI10 of the analog input acquisition module; the first interface AI01 of the analog input acquisition module is connected to the first current transformer CT1; the tenth interface AI10 of the analog input acquisition module is connected to the voltage transformer PT.

[0098] In this embodiment of the present application, the first interface AI01 of the analog input acquisition module is the analog input port for the ground fault protection device. Similarly, the other interfaces of the analog input acquisition module AI are also analog input ports for the ground fault protection device. Thus, the analog input acquisition module AI is used to acquire the voltage signal of the voltage transformer PT and the current signal of the first current transformer CT1 and convert them into low-voltage signals.

[0099] The switch input acquisition module BI includes a first interface BI01 of the switch input acquisition module. The first interface BI01 of the switch input acquisition module is connected to the circuit breaker DL and is used to acquire the closed / open state of the circuit breaker DL. Therefore, the switch input acquisition module BI is used to acquire the open position of the circuit breaker DL.

[0100] In the embodiment of the present application, the first interface BI01 of the switch value input acquisition module and the second interface BI02 of the switch value input acquisition module are both switch value input ports of the ground protection device.

[0101] The output module BO includes a fifth interface BO05 of the output module and a sixth interface BO06 of the output module, wherein the fifth interface BO05 of the output module is connected to the tripping circuit of the circuit breaker DL for outputting an opening instruction; the sixth interface BO06 of the output module is connected to the closing circuit of the circuit breaker DL for outputting a closing instruction.

[0102] In the embodiment of the present application, the fifth interface BO05 and the sixth interface BO06 of the output module are both digital output ports of the ground fault protection device. Similarly, the other interfaces of the output module BO are also digital output ports of the ground fault protection device. The output module BO is used to send opening and closing commands to the circuit breaker DL and / or to send a tripping command to at least one of the first circuit breaker DL1, the second circuit breaker DL2, the third circuit breaker DL3, and the fourth circuit breaker DL4.

[0103] The grounding protection device 20 of the embodiment of the present application, based on the above-mentioned structure, can control the opening / closing state of the circuit breaker DL, and can also realize the tripping of the first circuit breaker DL1, the second circuit breaker DL2, the third circuit breaker DL3, and the fourth circuit breaker DL4, so as to respond quickly when a fault occurs. Compared with the existing technology, it saves the resource investment of adding isolation transformers and supporting protection and measurement and control equipment.

[0104] In one possible implementation, as shown in Figure 3, the processing module U includes a first processing circuit U1 and a second processing circuit U2 connected in parallel, and the output module BO includes an output relay J1 and a starter relay J2. The output relay J1 includes a first output relay J11, a second output relay J12, a third output relay J13, a fourth output relay J14, a fifth output relay J15, and a sixth output relay J16. The fifth output relay J15 serves as the output module's fifth interface BO05, while the sixth output relay J16 serves as the output module's sixth interface BO06.

[0105] It should be understood that the grounding protection device 20 detecting that the 35 kV busbar zero-sequence voltage 3U0 exceeds a threshold can serve as a criterion for the grounding protection device to activate relay J2 to open the positive power supply of output relay J1, thereby connecting output relay J1 to the positive power supply. The grounding protection device 20 detecting that the 35 kV busbar zero-sequence voltage 3U0 exceeds a threshold condition means that the 35 kV busbar zero-sequence voltage 3U0 is greater than or equal to a preset threshold (i.e., 3U0 ≥ Uset).

[0106] The first processing circuit U1 includes a first analog-to-digital conversion module 21 and a first processor 22 connected in sequence, and the second processing circuit U2 includes a second analog-to-digital conversion module 23 and a second processor 24 connected in sequence.

[0107] It should be understood that the first analog-to-digital conversion module 21 and the second analog-to-digital conversion module 23 may both be referred to as analog-to-digital conversion A / D modules. The first processor 22 may be referred to as a protection DSP module, and the second processor 24 may be referred to as a startup DSP module.

[0108] The first analog-to-digital conversion module 21 converts the small voltage signal collected by the analog input acquisition module AI into a digital signal through A / D sampling and holding and transmits it to the first processor 22; similarly, the second analog-to-digital conversion module 23 converts the small voltage signal collected by the analog input acquisition module AI into a digital signal through A / D sampling and holding and transmits it to the second processor 24.

[0109] The first processor 22 is connected to the first outlet relay J11, the second outlet relay J12, the third outlet relay J13, the fourth outlet relay J14, the fifth outlet relay J15 and the sixth outlet relay J16 respectively.

[0110] In the embodiment of the present application, the ground protection device 20 further includes a power supply module. The power supply module is used to provide power required by the ground protection device 20.

[0111] The second processor 24 is used to execute the fault detection process, mainly for threshold comparison. When at least one ground fault of any type is detected (that is, all ground faults meet the following condition: 3U0≥Uset), the positive power supply of the output relay J1 is opened by starting the relay J2 to connect the output relay J1 to the positive power supply.

[0112] The first processor 22 is configured to execute a protection logic calculation process, primarily for calculations and amplitude and phase comparisons, determine the type of ground fault, and generate a control signal containing an execution subject and an instruction type based on a control strategy corresponding to the ground fault type. This control signal then drives the output relay J1 to send an opening / closing instruction to the circuit breaker DL, and / or to send a protection trip signal to at least one of the first circuit breaker DL1, the second circuit breaker DL2, the third circuit breaker DL3, and the fourth circuit breaker DL4, so that the execution subject executes the corresponding instruction and completes the corresponding protection action. Different types of ground faults have different determination conditions and correspond to different control strategies. A detailed description of all ground fault types, their determination conditions, and their control strategies is provided in the aforementioned embodiment 1 and the following embodiment 3, and is not further elaborated here.

[0113] In one possible implementation, as shown in FIG3 , the grounding protection device 20 further includes a central processing unit 25 connected to both the first processor 22 and the second processor 24 , as well as a communication management module 26 , a timing module 27 and a human-computer interaction module 28 connected to both the central processing unit.

[0114] It should be understood that the central processing unit 25, also known as the central processing unit CPU module, is used to implement event sequence recording (SOE), recording, printing, time synchronization, provide a human-computer interaction interface for the human-computer interaction module 28, and communicate with the supervisory control and data acquisition (SCADA) system.

[0115] That is to say, the grounding protection device 20 uploads the operation information and event sequence records of the grounding protection device 20 to the monitoring system SCADA through the station control layer switch and the remote motor through the communication port, so that the background operation personnel of the monitoring system SCADA can monitor the new energy power station and the grounding protection system of the new energy power station.

[0116] It should be understood that the timing module 27 may also refer to a GPS timing module. The GPS timing module is used to control the real-time synchronization of the data acquisition module (i.e., the analog input acquisition module AI and the switch input acquisition module BI) with the protection DSP module and the start-up DSP module, ensuring that the protection logic calculation process and the data collected by the data acquisition module are performed at the same time. This also ensures time synchronization between the grounding protection device 20 and the monitoring system (SCADA) and the dispatching system.

[0117] The human-computer interaction module 28 is used to query and modify instructions. The user can obtain the operating status of all equipment in the new energy power station by inputting relevant settings into the human-computer interaction module 28.

[0118] In addition, the embodiment of the present application may further be provided with a protection information substation and a fault recording device respectively connected to the grounding protection device 20, wherein the grounding protection device 20 uploads the fault information corresponding to the protection action (including: grounding fault type) to the protection information substation through the communication port, and the protection information substation is used to collect fault information and upload it to the scheduling system when a protection action occurs in the grounding protection system of the new energy power station; the grounding protection device 20 outputs the switching quantity of the protection action to the fault recording device through the switching quantity output port, so that the fault recording device records the waveform when the parameter exceeds the limit (for example: 3U0≥Uset, 3I01≥Iset, etc.), the switch changes (that is, the state of at least one circuit breaker changes), and a protection action occurs.

[0119] In order to solve the problem of inconsistent neutral point grounding methods caused by the connection of new energy power stations to the 35kV distribution network, the embodiment of the present application proposes a new grounding protection system: a new energy power station grounding protection system. This system is an adaptive grounding protection system using the neutral point grounding method. It combines the advantages of the low-resistance grounding method and the ungrounded method. It can not only meet the requirements of the 35kV distribution network to operate with a ground fault for 1 to 2 hours and ensure power supply continuity, but also meet the requirements of the new energy power station to quickly cut off the ground fault and ensure equipment safety.

[0120] Example 3:

[0121] Figure 4 is a schematic diagram of another grounding protection system for a new energy power station provided in an embodiment of the present application. As shown in Figure 4, the multiple branches L3 further include: a collector line L32 and an SVG line L33; a second current transformer CT2 is provided on the collector line L32, and a third current transformer CT3 is provided on the SVG line L33; and a fourth current transformer CT4 is provided on the grounding transformer branch L31 between the grounding transformer T and the busbar L1. The number of collector lines L32 can be one or more, and therefore this embodiment does not impose a specific limit on their number.

[0122] The second current transformer CT2 , the third current transformer CT3 and the fourth current transformer CT4 are used to detect the current of the collector line L32 , the current of the SVG line L33 and the current of the grounding transformer L31 , respectively.

[0123] It should be understood that the second current transformer CT2 is a zero-sequence current transformer on collector line L32. The current of collector line L32 detected by it, or the 35kV collector line zero-sequence current, can be denoted as 3I02. The third current transformer CT3 is a zero-sequence current transformer on SVG line L33. The current of SVG line L33 detected by it, or the 35kV SVG zero-sequence current, can be denoted as 3I03. The fourth current transformer CT4 is a zero-sequence current transformer on grounding transformer branch L31. The current of grounding transformer branch L31 detected by it, or the 35kV grounding transformer zero-sequence current, can be denoted as 3I04.

[0124] In the embodiment of the present application, the grounding protection device 20 is further used to combine the output line zero-sequence current 3I01, the 35kV collector line zero-sequence current 3I02, the 35kV SVG zero-sequence current 3I03, the 35kV grounding transformer zero-sequence current 3I04, etc. to determine whether there is a busbar L1 ground fault, a grounding transformer branch L31 ground fault, a collector line L32 ground fault, an SVG line L33 ground fault, or other ground fault types when the neutral point resistance of the 35kV grounding transformer is not grounded. The specific analysis is as follows:

[0125] When the circuit breaker DL is in the open state, the grounding protection device 20 performs a threshold comparison on the voltage of the busbar L1. If the voltage of the busbar L1 is greater than or equal to the preset threshold, the voltage of the busbar L1, the current of the transmission line L2, the current of the collector line L32, the current of the SVG line L33 and the current of the grounding transformer L31 are calculated and the amplitude and phase are compared to determine whether a ground fault has occurred in the busbar L1, thereby obtaining a second judgment result.

[0126] In the embodiment of the present application, the ground fault type includes a busbar L1 ground fault. The ground protection device 20 can determine whether this type of fault occurs based on the determination conditions of the busbar L1 ground fault type. The determination conditions of the busbar L1 ground fault type are: 3U0≥Uset, The circuit breaker DL is in an open state, 3I01≥preset current value Iset, 3I02≥preset current value Iset, 3I03≥preset current value Iset, and 3I04≥preset current value Iset.

[0127] In a specific example, the grounding protection device 20 can first perform a threshold comparison on the 35kV busbar zero-sequence voltage 3U0, and collect the closing / opening status of the circuit breaker DL, and then determine whether to perform a judgment on the other eight conditions based on the threshold comparison result and the collection result of whether the circuit breaker DL is in the open state. That is, if 3U0≤Uset or the circuit breaker DL is in the closed state, it is not necessary to perform a judgment on the other eight conditions, and the second judgment result is: no grounding fault has occurred in the busbar L1. If 3U0≥Uset and the circuit breaker DL is in the open state, the grounding protection device 20 can continue to be used to detect and compare the phases of the 35kV busbar zero-sequence voltage and the zero-sequence current 3I01 of the transmission line, the zero-sequence current 3I02 of the 35kV collector line, the zero-sequence current 3I03 of the 35kV SVG, and the zero-sequence current 3I04 of the 35kV grounding transformer, and obtain a phase comparison result. and Threshold comparisons are performed on the transmission line zero-sequence current 3I01, the 35kV collector line zero-sequence current 3I02, the 35kV SVG zero-sequence current 3I03, and the 35kV grounding transformer zero-sequence current 3I04. If all phase comparison results and all threshold comparison results meet the judgment conditions for a ground fault of the busbar L1 type, the second judgment result is that a ground fault has occurred on the busbar L1.

[0128] For the grounding fault type of busbar L1 grounding fault, the corresponding control strategy is: after the delay t, the grounding protection device 20, the first outlet relay J11, the second outlet relay J12, the third outlet relay J13 and the fourth outlet relay J14 are all activated, and a protection tripping signal (referred to as a tripping instruction for short) is sent to the first circuit breaker DL1, the second circuit breaker DL2, the third circuit breaker DL3 and the fourth circuit breaker DL4 respectively, so that the first circuit breaker DL1, the second circuit breaker DL2, the third circuit breaker DL3 and the fourth circuit breaker DL4 all execute the tripping instruction, and then switch to the opening state (that is, the first circuit breaker DL1, the second circuit breaker DL2, the third circuit breaker DL3 and the fourth circuit breaker DL4 are tripped), and all branches in the 35kV new energy power station are tripped to isolate the fault point.

[0129] In the embodiment of the present application, a busbar L1 ground fault is one type of ground fault. In addition to the grid-side fault of the outgoing transmission line L2 described in Example 1 and the busbar L1 ground fault described here, the ground fault types in the embodiment of the present application also include branch fault types such as ground transformer branch L31 ground fault, collector line L32 ground fault, and SVG line L33 ground fault.

[0130] When the circuit breaker DL is in the open state, the grounding protection device 20 performs a threshold comparison on the voltage of the busbar L1. If the voltage of the busbar L1 is greater than or equal to the preset threshold, the voltage of the busbar L1 and the current of the collector line L32 are calculated and the amplitude and phase are compared to determine whether a ground fault occurs in the collector line L32, thereby obtaining a third judgment result.

[0131] In the embodiment of the present application, the ground fault type includes branch faults, and the branch faults include ground transformer L31 ground fault, collector line L32 ground fault, and SVG line L33 ground fault. For the collector line L32 ground fault, the ground protection device 20 can determine whether this type of fault occurs based on the determination conditions of the collector line L32 ground fault type. Among them, the determination conditions of the collector line L32 ground fault type are: 3U0≥Uset, The circuit breaker DL is in the open state and 3I02 ≥ the preset current value Iset.

[0132] In a specific example, the grounding protection device 20 can first perform a threshold comparison on the 35kV busbar zero-sequence voltage 3U0, and collect the closing / opening status of the circuit breaker DL, and then determine whether to perform the judgment of the other two conditions based on the threshold comparison result and the collection result of whether the circuit breaker DL is in the open state. That is, if 3U0≤Uset or the circuit breaker DL is in the closed state, it is not necessary to judge the other two conditions, and the third judgment result is: the collector line L32 has no grounding fault. If 3U0≥Uset and the circuit breaker DL is in the open state, the grounding protection device 20 can continue to be used to detect and compare the phases of the 35kV busbar zero-sequence voltage and the 35kV collector line zero-sequence current 3I02 to obtain the phase comparison result. A threshold comparison is performed on the 35kV collector line zero-sequence current 3I02; if both the phase comparison result and the threshold comparison result meet the determination condition of the collector line L32 ground fault type, the third judgment result is that a ground fault occurs in the collector line L32.

[0133] For the grounding fault type of the collector line L32 grounding fault, the corresponding control strategy is: the second output relay J12 of the grounding protection device 20 is activated after a delay t, and a protection tripping signal is sent to the second circuit breaker DL2, so that the second circuit breaker DL2 executes the tripping instruction, and then switches to the opening state (that is, trips the second circuit breaker DL2), trips the fault line to isolate the fault point.

[0134] When circuit breaker DL is in the open state, ground protection device 20 performs a threshold comparison on the voltage of busbar L1. If the voltage of busbar L1 is greater than or equal to the preset threshold, ground protection device 20 calculates the voltage of busbar L1 and the current of SVG line L33 and performs an amplitude and phase comparison to determine whether a ground fault has occurred in SVG line L33, thereby obtaining a fourth judgment result.

[0135] In the embodiment of the present application, the ground fault type includes branch faults, and the branch faults include ground transformer L31 ground fault, collector line L32 ground fault, and SVG line L33 ground fault. For the SVG line L33 ground fault, the ground protection device 20 can determine whether this type of fault has occurred based on the determination conditions of the SVG line L33 ground fault type. The determination conditions of the SVG line L33 ground fault type of ground fault are: 3U0≥Uset, The circuit breaker DL is in the open state and 3I03 ≥ the preset current value Iset.

[0136] In a specific example, the grounding protection device 20 can first perform a threshold comparison on the 35kV busbar zero-sequence voltage 3U0, and collect the closing / opening status of the circuit breaker DL, and then determine whether to perform the judgment of the other two conditions based on the threshold comparison result and the collection result of whether the circuit breaker DL is in the open state. That is, if 3U0≤Uset or the circuit breaker DL is in the closed state, it is not necessary to judge the other two conditions, and the fourth judgment result is: no grounding fault occurs in the SVG line L33. If 3U0≥Uset and the circuit breaker DL is in the open state, the grounding protection device 20 can continue to be used to detect and compare the phases of the 35kV busbar zero-sequence voltage and the 35kV SVG zero-sequence current 3I03 to obtain the phase comparison result. A threshold comparison is performed on the 35kV SVG zero-sequence current 3I03; if both the phase comparison result and the threshold comparison result meet the determination condition of the type of ground fault of the SVG line L33 ground fault, the fourth determination result is that a ground fault occurs in the SVG line L33.

[0137] For the ground fault type of SVG line L33, the corresponding control strategy is: after a delay t, the third output relay J13 of the ground protection device 20 is activated, and a protection trip signal is sent to the third circuit breaker DL3, so that the third circuit breaker DL3 executes the trip command and then switches to the open state (i.e., trips the third circuit breaker DL3), tripping the faulty line to isolate the fault point.

[0138] When the circuit breaker DL is in the open state, the grounding protection device 20 performs a threshold comparison on the voltage of the bus L1. If the voltage of the bus L1 is greater than or equal to the preset threshold, the voltage of the bus L1 and the current of the grounding transformer L31 are calculated and the amplitude and phase are compared to determine whether a grounding fault occurs in the grounding transformer L31, thereby obtaining a fifth judgment result.

[0139] In the embodiment of the present application, the ground fault type includes branch faults, and the branch faults include ground faults of the ground transformer branch L31, ground faults of the collector line L32, and ground faults of the SVG line L33. For the ground fault of the ground transformer branch L31, the ground protection device 20 can determine whether this type of fault occurs according to the determination conditions of the ground fault of the ground transformer branch L31. Among them, the determination conditions of the ground fault of the ground transformer branch L31 are: 3U0≥Uset, The circuit breaker DL is in the open state and 3I04 ≥ the preset current value Iset.

[0140] In a specific example, the grounding protection device 20 can first perform a threshold comparison on the 35kV busbar zero-sequence voltage 3U0, and collect the closing / opening status of the circuit breaker DL, and then determine whether to perform the judgment of the other two conditions based on the threshold comparison result and the collection result of whether the circuit breaker DL is in the open state. That is, if 3U0≤Uset or the circuit breaker DL is in the closed state, it is not necessary to judge the other two conditions, and the fifth judgment result is: no grounding fault occurs in the grounding transformer branch L31. If 3U0≥Uset and the circuit breaker DL is in the open state, the grounding protection device 20 can continue to be used to detect and compare the phase of the 35kV busbar zero-sequence voltage and the 35kV grounding transformer zero-sequence current 3I04 to obtain a phase comparison result. A threshold comparison is performed on the 35kV grounding transformer zero-sequence current 3I04; if both the phase comparison result and the threshold comparison result meet the judgment condition of the grounding fault of the grounding transformer branch L31, the fifth judgment result is that a grounding fault occurs in the grounding transformer branch L31.

[0141] For the grounding fault type of the grounding transformer branch L31, the corresponding control strategy is: the fourth output relay J14 of the grounding protection device 20 is activated after a delay t, and a protection tripping signal is sent to the fourth circuit breaker DL4, so that the fourth circuit breaker DL4 executes the tripping instruction, and then switches to the opening state (that is, trips the fourth circuit breaker DL4), trips the fault line to isolate the fault point.

[0142] The embodiments of the present application can accurately and effectively identify the faulty branch when a ground fault occurs in each branch, thereby improving the safety of the system.

[0143] In one possible implementation, as shown in FIG4 , the analog input acquisition module AI further includes: a second interface AI02 of the analog input acquisition module, a third interface AI03 of the analog input acquisition module, and a fourth interface AI04 of the analog input acquisition module. The second interface AI02 of the analog input acquisition module is connected to the second current transformer CT2. The third interface AI03 of the analog input acquisition module is connected to the third current transformer CT3. The fourth interface AI04 of the analog input acquisition module is connected to the fourth current transformer CT4.

[0144] In addition to collecting the voltage signal of the voltage transformer PT and the current signal of the first current transformer CT1 and converting them into corresponding small voltage signals, the analog input acquisition module AI is also used to collect the current signals of the second current transformer CT2, the third current transformer CT3 and the fourth current transformer CT4 and convert them into corresponding small voltage signals.

[0145] In the analog input acquisition module AI, the embodiment of the present application provides a corresponding interface for each current transformer and voltage transformer to realize the acquisition of current and voltage, and can provide data support for accurately identifying the fault type and fault line.

[0146] In one possible implementation, as shown in Figures 1 to 4 , the output module BO further includes a first output module interface BO01, a second output module interface BO02, a third output module interface BO03, and a fourth output module interface BO04. The first output module interface BO01 is a first output relay J11; the second output module interface BO02 is a second output relay J12; the third output module interface BO03 is a third output relay J13; and the fourth output module interface BO04 is a fourth output relay J14.

[0147] The outgoing line L2 is further provided with a first circuit breaker DL1 located between the first current transformer CT1 and the busbar L1; a trip circuit of the first circuit breaker DL1 is connected to the first interface BO01 of the output module.

[0148] The collector line L32 is further provided with a second circuit breaker DL2 located between the second current transformer CT2 and the busbar L1; a trip circuit of the second circuit breaker DL2 is connected to the second interface BO02 of the output module.

[0149] The SVG line L33 is further provided with a third circuit breaker DL3 located between the third current transformer CT3 and the busbar L1; a trip circuit of the third circuit breaker DL3 is connected to the third interface BO03 of the output module.

[0150] The grounding transformer branch L31 is further provided with a fourth circuit breaker DL4 located between the fourth current transformer CT4 and the busbar L1; a trip circuit of the fourth circuit breaker DL4 is connected to the fourth interface BO04 of the output module.

[0151] Processing module U is configured to, when the second determination result indicates a ground fault on busbar L1, send protective trip signals to first circuit breaker DL1, second circuit breaker DL2, third circuit breaker DL3, and fourth circuit breaker DL4 via output module interface BO01, output module interface BO02, output module interface BO03, and output module interface BO04, respectively. This technical solution provides a detailed description of the control strategy for busbar L1 ground fault.

[0152] The processing module U is further configured to send a protection tripping signal to the second circuit breaker DL2 through the second interface BO02 of the output module when the third judgment result is that a ground fault occurs in the collector line L32.

[0153] This protection trip signal is also called a tripping command. This part of the technical solution is a detailed description of the control strategy for the ground fault type of the collector line L32 ground fault.

[0154] Processing module U is further configured to send a protective trip signal to third circuit breaker DL3 via third interface BO03 of the output module when the fourth determination result indicates a ground fault on SVG line L33. This technical solution provides a detailed description of the control strategy for a ground fault on SVG line L33.

[0155] The processing module U is further configured to send a protective trip signal to the fourth circuit breaker DL4 via the fourth interface BO04 of the output module when the fifth determination result indicates a ground fault in the ground transformer L31. This technical solution provides a detailed description of the control strategy for the ground fault type of the ground transformer L31.

[0156] It can be seen that, in addition to sending opening and closing commands to the circuit breaker DL, the output module BO is also used to send a protection trip signal to at least one of the first circuit breaker DL1, the second circuit breaker DL2, the third circuit breaker DL3 and the fourth circuit breaker DL4.

[0157] In the embodiment of the present application, a corresponding interface is provided for each circuit breaker in the output module BO to achieve accurate implementation of the control strategy, and can provide support for isolating fault points and ensuring system safety.

[0158] In a possible implementation, as shown in FIG4 , the system further includes a fifth current transformer CT5 disposed between the resistor R and the ground, and a temperature-controlled switch TJ in the resistor chamber where the resistor R is located.

[0159] It should be understood that since the switching quantity includes input quantity and output quantity, it is a digital signal with only two states, 0 and 1, which respectively indicate that the relay contacts are open and closed. Therefore, the temperature control switch TJ can be understood as the over-temperature contact of the thermostat in the resistance cabinet of the 35kV grounding transformer, which switches from the open state to the closed state after exceeding the preset temperature threshold.

[0160] As shown in Figure 5, the resistor compartment 300, transformer compartment 100, and operating electrical equipment compartment 200 form a 35kV grounding transformer resistance cabinet (referred to as the grounding transformer resistance cabinet). The resistor R, the fifth current transformer CT5, and the temperature-controlled switch TJ are installed within the resistor compartment 300. The temperature-controlled switch TJ can be mounted on the cabinet body of the resistor compartment 300. The grounding transformer T is installed within the transformer compartment 100. Furthermore, the aforementioned disconnector GL and circuit breaker DL are installed within the operating electrical equipment compartment 200.

[0161] The operating and electrical equipment room 200 also houses the circuit breaker DL's closing and opening indicators, which indicate closing and opening, respectively. The circuit breaker DL's closing and opening buttons are also housed within the operating and electrical equipment room 200 for easy manual operation. The operating and electrical equipment room 200 also houses the operating handle of the disconnector GL, which is used to operate the disconnector GL. It should be understood that the operating and electrical equipment room 200 is also referred to as the switch room.

[0162] It should be noted that, in addition to the corresponding branch integrated protection and measurement and control device on the grounding transformer branch L31, corresponding branch integrated protection and measurement and control devices are also present on the collector line L32 and the SVG line L33.

[0163] The analog input acquisition module AI further includes a fifth interface AI05 of the analog input acquisition module. The fifth interface AI05 of the analog input acquisition module is connected to the fifth current transformer CT5.

[0164] The fifth current transformer CT5 is used to detect the current of the resistor R. The fifth current transformer CT5 is a grounded-to-neutral current transformer, and the grounded-to-neutral current detected by the fifth current transformer CT5 can be recorded as 3I05.

[0165] The second interface BI02 of the switch input acquisition module is connected to the temperature control switch TJ and is used to acquire the status of the temperature control switch TJ. Therefore, the switch input acquisition module BI is used not only to acquire the open position of the circuit breaker DL, but also to acquire the switch signal of the temperature control switch TJ.

[0166] The processing module U is used to calculate the accumulated heat (3I05) of the resistor R according to the current of the resistor R when the temperature control switch TJ is in the closed state. 2 t, accumulated heat in resistor R (3I05)2 t is greater than or equal to the preset heat threshold Q set In the case of a tripping instruction, the fifth interface BO05 of the output module is sent to the circuit breaker DL, and after a delay of a preset time period, a protection tripping signal is sent to the fourth circuit breaker DL4 through the fourth interface BO04 of the output module.

[0167] In addition to the following ground fault types, this embodiment of the application also provides: outgoing line L2 fault, busbar L1 ground fault, ground transformer L31 ground fault, collector line L32 ground fault, SVG line L33 ground fault, etc., and also provides: execution fault (i.e., fault caused by circuit breaker DL failure). For execution fault, the judgment conditions are: 3U0≥Uset, (3I05) 2 t≥Q set The control strategy is as follows: the fifth output relay J15 is actuated, sending an opening command to the circuit breaker DL again; and after a delay t, the sixth output relay J16 is actuated, sending a protection trip signal to the fourth circuit breaker DL4.

[0168] The embodiments of the present application can implement switching of the grounding protection system between resistance grounding mode and ungrounded mode in various situations. Therefore, the grounding protection system for new energy power stations provided by the present application can combine the advantages of ungrounded mode and low-resistance grounding mode, meeting the requirements of the distribution network operating in an ungrounded mode with a ground fault for 1 to 2 hours to ensure power supply continuity, while also meeting the requirements of new energy power stations for rapid removal of ground faults.

[0169] As can be seen from Figure 4, an embodiment of the present application provides a grounding protection system for a new energy power station connected to a 35kV distribution network. A grounding transformer T is connected to the 35kV bus provided by the new energy power station. The neutral point of the grounding transformer T is grounded in sequence through the isolating switch GL, the circuit breaker DL, and the resistor R. The grounding end of the resistor R is installed with a fifth current transformer CT5. The 35kV bus zero-sequence voltage 3U0 detected by the voltage transformer PT on the 35kV bus is connected to the tenth interface AI10 of the analog input acquisition module, the outgoing line zero-sequence current 3I01 is connected to the first interface AI01 of the analog input acquisition module, the 35kV collector line zero-sequence current 3I02 is connected to the second interface AI02 of the analog input acquisition module, and the 35kV The SVG zero-sequence current 3I03 is connected to the third interface AI03 of the analog input acquisition module, the 35kV grounding transformer zero-sequence current 3I04 is connected to the fourth interface AI04 of the analog input acquisition module, and the grounding transformer neutral point current 3I05 is connected to the fifth interface AI05 of the analog input acquisition module. The tripping circuit of the first circuit breaker DL1 located on the transmission line L2 is connected to the first interface BO01 of the output module, the tripping circuit of the second circuit breaker DL2 located on the collector line L32 is connected to the second interface BO02 of the output module, the tripping circuit of the third circuit breaker DL3 located on the SVG line L33 is connected to the third interface BO03 of the output module, the tripping circuit of the fourth circuit breaker DL4 located on the grounding transformer L31 is connected to the fourth interface BO04 of the output module, the tripping circuit of the circuit breaker DL is connected to the fifth interface BO05 of the output module, the closing circuit of the circuit breaker DL is connected to the sixth interface BO06 of the output module, the opening position of the circuit breaker DL is connected to the first interface BI01 of the switch input acquisition module, and the temperature control switch TJ is connected to the second interface BI02 of the switch input acquisition module.

[0170] Example 4:

[0171] Figure 6 is a flow chart of a method for grounding protection of a new energy power station provided in an embodiment of the present application. As shown in Figure 6, the method of this embodiment is applied to the grounding protection system of a new energy power station provided in any one of Examples 1 to 3. The method of this embodiment includes the following steps:

[0172] S10. The voltage transformer is used to detect the voltage of the busbar and send the voltage of the busbar to the grounding protection device. The first current transformer is used to detect the current of the outgoing line and send the current of the outgoing line to the grounding protection device.

[0173] S20. The grounding protection device is used to collect the voltage of the busbar and the current of the outgoing line, perform amplitude and phase comparison, collect the closing / opening status of the circuit breaker, and determine whether a grounding fault occurs on the grid side to which the outgoing line is connected, thereby obtaining a first judgment result; and generate a corresponding opening / closing instruction based on the first judgment result, and issue the opening / closing instruction to the circuit breaker.

[0174] S30: The circuit breaker performs corresponding opening / closing operations according to the opening / closing instruction.

[0175] The present application embodiment analyzes the method as follows according to the changes in the scenario:

[0176] (1) During normal operation, the neutral point of the 35kV distribution network is not grounded, while the neutral point of the new energy power station connected to the 35kV distribution network is grounded through a low resistance.

[0177] (2) If a single-phase grounding fault occurs in the area during normal operation of the new energy power station (outside the area refers to the 35kV distribution network connected by the transmission line), then since the neutral point of the new energy power station is grounded through low resistance, its zero-sequence current is relatively large.

[0178] When the fault point is on the transmission line, the transmission line differential protection will be activated to clear the fault; when the fault point is on the 35kV busbar in the new energy power station, the 35kV busbar differential protection will be activated to clear the fault; when the fault point occurs on the collector line, SVG line, or grounding transformer branch in the new energy power station, the corresponding branch integrated protection and measurement and control device will be activated to clear the fault; in addition, the grounding transformer zero-sequence protection can serve as remote backup protection for collector line grounding faults and SVG line grounding faults.

[0179] (3) If a single-phase grounding fault occurs outside the zone during normal operation of the new energy power station, the zero-sequence current is large because the neutral point of the new energy power station is grounded via low resistance, which facilitates accurate fault line selection in the 35kV distribution network. Furthermore, by detecting and comparing the phases of the 35kV busbar zero-sequence voltage 3U0 and the zero-sequence current 3I01 of the outgoing line, the grounding protection device sends a trip signal to the circuit breaker DL, tripping the circuit breaker DL. The new energy power station switches from low-resistance grounding to ungrounded mode.

[0180] To prevent the circuit breaker DL from failing to operate and the neutral point resistor of the 35kV grounding transformer from being damaged by overheating due to long-term current passing through it, the grounding protection device detects the closed state of the temperature control switch TJ and the current 3I05 at the neutral point of the grounding transformer, and performs heat accumulation calculation. If failure to operate occurs, it will instantly operate again to trip the circuit breaker DL, and after a delay t, it will operate on the fourth circuit breaker DL4 to trip the fourth circuit breaker DL4, thereby doubly protecting the low resistance of the new energy power station in terms of operational safety.

[0181] (4) If a single-phase grounding fault occurs outside the zone of the new energy power station and a single-phase grounding fault occurs on the same phase within the zone at the same time, then since the neutral point of the new energy power station is not grounded, the fault current is the system capacitance current, and the fault current is divided at the fault grounding points outside and inside the zone. The zero-sequence voltage and zero-sequence current of the fault branch within the zone are compared by amplitude and phase, and it can be determined that the comparison result meets the action condition. The grounding protection device is activated to send a protection trip signal corresponding to the fault branch to trip the fault branch and isolate the fault point. For example, when the fault point of the single-phase grounding fault on the same phase within the zone is on the 35kV busbar, collector line, SVG line, or grounding transformer branch of the new energy power station, the grounding protection device is activated to clear the fault.

[0182] During the period when a single-phase grounding fault occurs outside the new energy power station, a single-phase grounding fault of the opposite phase occurs simultaneously in the zone, which is equivalent to a two-phase short circuit and grounding. The corresponding branch integrated protection and measurement and control device can perform overcurrent protection to cut off the fault. At the same time, the grounding protection device, as a backup protection device, can also be activated to cut off the fault.

[0183] (5) If the new energy power station is restored after a period of time after a single-phase grounding fault occurs outside the zone, and the 35kV busbar zero-sequence voltage 3U0 returns to the limit, the grounding protection device sends a closing command to the circuit breaker DL after a delay t, which can enable the new energy power station to switch from the ungrounded mode to the low-resistance grounding mode.

[0184] In summary, the embodiment of the present application distinguishes between faults outside and inside the zone by comparing the zero-sequence voltage and zero-sequence current amplitude and phase, and judges the occurrence / elimination of the fault outside the zone according to the over-limit action and return of the 35kV busbar zero-sequence voltage 3U0, and performs the circuit breaker DL opening / closing operation to realize the automatic switching of the neutral point grounding mode of the new energy power station; when a fault inside the zone occurs during the period of the fault outside the zone, the embodiment can improve the accuracy of line selection and tripping by comparing the zero-sequence voltage and zero-sequence current amplitude and phase. The beneficial effects of this embodiment are: (1) It can combine the advantages of the ungrounded mode and the low-resistance grounding mode to construct a neutral point adaptive grounding system for the new energy power station to access the distribution network; (2) It saves the resource investment of adding isolation transformers and supporting protection and measurement and control equipment.

[0185] The implementation principle and technical effects of the grounding protection method for a new energy power station provided in this embodiment are similar to those of the grounding protection system for a new energy power station provided in the above-mentioned system embodiment, and are not described in detail here.

[0186] It should be noted that the user information and data involved in this application (including but not limited to data used for analysis, stored data, displayed data, etc.) are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with the relevant laws, regulations and standards of the relevant countries and regions, and provide corresponding operation portals for users to choose to authorize or refuse. In other words, in the technical solution of this application, the collection, storage, use, processing, transmission, provision and disclosure of user personal information involved are in compliance with the provisions of relevant laws and regulations and do not violate public order and good morals.

[0187] According to an embodiment of the present application, the present application also provides an electronic device and a readable storage medium.

[0188] Figure 7 is a schematic diagram of the structure of an electronic device provided in an embodiment of the present application. The electronic device includes a receiver 70, a transmitter 71, at least one processor 72, and a memory 73. The electronic device composed of the above components can be used to implement the above-mentioned specific embodiments of the present application, which will not be repeated here.

[0189] An embodiment of the present application further provides a computer-readable storage medium, in which computer-executable instructions are stored. When a processor executes the computer-executable instructions, each step of the method in the above embodiment is implemented.

[0190] An embodiment of the present application further provides a computer program product, including a computer program, which implements each step of the method in the above embodiment when executed by a processor.

[0191] Various embodiments of the systems and techniques described above in this application can be implemented in digital electronic circuit systems, integrated circuit systems, field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), application specific standard products (ASSPs), system-on-chip systems (SOCs), programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various embodiments may include being implemented in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which can be a special purpose or general purpose programmable processor that can receive data and instructions from a storage system, at least one input device, and at least one output device, and transmit data and instructions to the storage system, the at least one input device, and the at least one output device.

[0192] It should be understood that the various forms of the processes shown above can be used to reorder, add, or delete steps. For example, the steps described in this application can be performed in parallel, sequentially, or in a different order, as long as the desired results of the technical solutions disclosed in this application can be achieved. This is not a limitation herein.

[0193] The above specific embodiments do not constitute a limitation on the scope of protection of this application. Those skilled in the art will appreciate that various modifications, combinations, sub-combinations, and substitutions may be made based on design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the principles of this application shall be included within the scope of protection of this application.

Claims

1. A new energy power station grounding protection system, characterized in that: include: A grounding neutral point device (10), a first current transformer (CT1), a voltage transformer (PT) and a grounding protection device (20); The new energy power station comprises a plurality of lines, wherein the plurality of lines comprise: a busbar (L1), a transmission line (L2) and a plurality of branches (L3); the branch (L3) and the transmission line (L2) are respectively connected to the busbar (L1); the busbar (L1) is provided with the voltage transformer (PT), and the transmission line (L2) is provided with the first current transformer (CT1); the voltage transformer (PT) and the first current transformer (CT1) are respectively connected to the grounding protection device (20); The voltage transformer (PT) is used to detect the voltage of the busbar (L1); the first current transformer (CT1) is used to detect the current of the output line (L2); The multiple branches (L3) include a grounding transformer branch (L31) provided with a grounding transformer (T) and the grounding transformer neutral point device (10); the grounding transformer neutral point device (10) includes an isolating switch (GL), a circuit breaker (DL) and a resistor (R) connected in sequence; the high-voltage side of the grounding transformer (T) is connected to the busbar (L1), and the neutral point of the grounding transformer (T) is grounded through the isolating switch (GL), the circuit breaker (DL) and the resistor (R) in sequence; The grounding protection device (20) is used to collect the voltage of the busbar (L1) and the current of the transmission line (L2), perform amplitude and phase comparison, collect the closing / opening state of the circuit breaker (DL), and judge whether a grounding fault occurs on the power grid side to which the transmission line (L2) is connected, and obtain a first judgment result; generate a corresponding opening / closing instruction according to the first judgment result, and issue an opening / closing instruction to the circuit breaker (DL); The circuit breaker (DL) performs corresponding opening / closing operations according to the opening / closing instruction.

2. The new energy power station grounding protection system according to claim 1, characterized in that: The grounding protection device (20) comprises: a processing module (U), and an analog input acquisition module (AI), a switch input acquisition module (BI) and an output module (BO) respectively connected to the processing module (U); The analog input acquisition module (AI) comprises a first interface (AI01) of the analog input acquisition module and a tenth interface (AI10) of the analog input acquisition module; the first interface (AI01) of the analog input acquisition module is connected to the first current transformer (CT1); the tenth interface (AI10) of the analog input acquisition module is connected to the voltage transformer (PT); The switch quantity input acquisition module (BI) comprises a first interface (BI01) of the switch quantity input acquisition module, the first interface (BI01) of the switch quantity input acquisition module is connected to the circuit breaker (DL) and is used to acquire the closing / opening state of the circuit breaker (DL); The output module (BO) comprises a fifth interface (BO05) of the output module and a sixth interface (BO06) of the output module, wherein the fifth interface (BO05) of the output module is connected to the tripping circuit of the circuit breaker (DL) for outputting an opening instruction; and the sixth interface (BO06) of the output module is connected to the closing circuit of the circuit breaker (DL) for outputting a closing instruction.

3. The new energy power station grounding protection system according to claim 2, characterized in that: The processing module (U) includes a first processing circuit (U1) and a second processing circuit (U2) connected in parallel, and the output module (BO) includes an output relay (J1) and a start relay (J2); wherein the output relay (J1) includes a first output relay (J11), a second output relay (J12), a third output relay (J13), a fourth output relay (J14), a fifth output relay (J15) and a sixth output relay (J16); the fifth output relay (J15) is the fifth interface (BO05) of the output module; the sixth output relay (J16) is the sixth interface (BO06) of the output module; The first processing circuit (U1) comprises a first analog-to-digital conversion module (21) and a first processor (22) connected in sequence, and the second processing circuit (U2) comprises a second analog-to-digital conversion module (23) and a second processor (24) connected in sequence; The first processor (22) is respectively connected to the first output relay (J11), the second output relay (J12), the third output relay (J13), the fourth output relay (J14), the fifth output relay (J15) and the sixth output relay (J16); the second processor (24) is connected to the start relay (J2); The start relay (J2) controls whether the positive power supply of the output relay (J1) is open.

4. The new energy power station grounding protection system according to claim 3 is characterized in that: The multiple branches (L3) further include: a collector line (L32) and an SVG line (L33); a second current transformer (CT2) is provided on the collector line (L32), and a third current transformer (CT3) is provided on the SVG line (L33); a fourth current transformer (CT4) is provided on the grounding transformer branch (L31) between the grounding transformer (T) and the busbar (L1); The second current transformer (CT2), the third current transformer (CT3) and the fourth current transformer (CT4) are used to detect the current of the collector line (L32), the current of the SVG line (L33) and the current of the ground transformer (L31), respectively; The grounding protection device (20) performs threshold comparison on the voltage of the busbar (L1) when the circuit breaker (DL) is in an open state. If the voltage of the busbar (L1) is greater than or equal to a preset threshold, the voltage of the busbar (L1), the current of the transmission line (L2), the current of the collector line (L32), the current of the SVG line (L33) and the current of the grounding transformer (L31) are calculated and compared in amplitude and phase to determine whether a grounding fault occurs in the busbar (L1) and obtain a second judgment result; The grounding protection device (20) performs threshold comparison on the voltage of the bus (L1) when the circuit breaker (DL) is in an open state. If the voltage of the bus (L1) is greater than or equal to the preset threshold, the voltage of the bus (L1) and the current of the collector line (L32) are calculated and compared in amplitude and phase to determine whether a grounding fault occurs in the collector line (L32), thereby obtaining a third judgment result; The grounding protection device (20) performs threshold comparison on the voltage of the bus (L1) when the circuit breaker (DL) is in an open state. If the voltage of the bus (L1) is greater than or equal to the preset threshold, the voltage of the bus (L1) and the current of the SVG line (L33) are calculated and compared in amplitude and phase to determine whether a grounding fault occurs in the SVG line (L33), thereby obtaining a fourth determination result. When the circuit breaker (DL) is in an open state, the grounding protection device (20) performs a threshold comparison on the voltage of the bus (L1); if the voltage of the bus (L1) is greater than or equal to the preset threshold, the voltage of the bus (L1) and the current of the grounding transformer (L31) are calculated and compared in amplitude and phase to determine whether a grounding fault occurs in the grounding transformer (L31), thereby obtaining a fifth judgment result.

5. The new energy power station grounding protection system according to claim 4, characterized in that: The analog input acquisition module (AI) further comprises: a second interface (AI02) of the analog input acquisition module, a third interface (AI03) of the analog input acquisition module and a fourth interface (AI04) of the analog input acquisition module, wherein: The second interface (AI02) of the analog input acquisition module is connected to the second current transformer (CT2); The third interface (AI03) of the analog input acquisition module is connected to the third current transformer (CT3); The fourth interface (AI04) of the analog input acquisition module is connected to the fourth current transformer (CT4).

6. The new energy power station grounding protection system according to claim 4, characterized in that: The output module (BO) further comprises a first interface (BO01) of the output module, a second interface (BO02) of the output module, a third interface (BO03) of the output module and a fourth interface (BO04) of the output module; wherein the first interface (BO01) of the output module is a first output relay (J11); the second interface (BO02) of the output module is a second output relay (J12); the third interface (BO03) of the output module is a third output relay (J13); the fourth interface (BO04) of the output module is a fourth output relay (J14); The output line (L2) is also provided with a first circuit breaker (DL1) located between the first current transformer (CT1) and the busbar (L1); a tripping circuit of the first circuit breaker (DL1) is connected to a first interface (BO01) of the output module; The collector line (L32) is also provided with a second circuit breaker (DL2) located between the second current transformer (CT2) and the busbar (L1); the tripping circuit of the second circuit breaker (DL2) is connected to the second interface (BO02) of the output module; The SVG line (L33) is also provided with a third circuit breaker (DL3) located between the third current transformer (CT3) and the busbar (L1); the tripping circuit of the third circuit breaker (DL3) is connected to the third interface (BO03) of the output module; The grounding transformer (L31) is also provided with a fourth circuit breaker (DL4) located between the fourth current transformer (CT4) and the busbar (L1); the tripping circuit of the fourth circuit breaker (DL4) is connected to the fourth interface (BO04) of the output module; The processing module (U) is used to send a protection trip signal to the first circuit breaker (DL1), the second circuit breaker (DL2), the third circuit breaker (DL3) and the fourth circuit breaker (DL4) respectively through the first interface (BO01) of the output module, the second interface (BO02) of the output module, the third interface (BO03) of the output module and the fourth module (BO04) of the output module when the second judgment result is that the bus (L1) has a ground fault; The processing module (U) is further configured to send a protection trip signal to the second circuit breaker (DL2) through the second interface (BO02) of the output module when the third judgment result is that a ground fault occurs in the collector line (L32); The processing module (U) is further configured to send a protection tripping signal to the third circuit breaker (DL3) through the third interface (BO03) of the output module when the fourth judgment result is that a ground fault occurs in the SVG line (L33); The processing module (U) is further configured to send a protection trip signal to the fourth circuit breaker (DL4) through the fourth interface (BO04) of the output module when the fifth judgment result is that a ground fault occurs in the grounding transformer branch (L31).

7. The new energy power station grounding protection system according to claim 6, characterized in that: The system further comprises a fifth current transformer (CT5) arranged between the resistor (R) and the ground, and a temperature-controlled switch (TJ) in a resistor chamber where the resistor (R) is located; The analog quantity input acquisition module (AI) further comprises a fifth interface (AI05) of the analog quantity input acquisition module, and the fifth interface (AI05) of the analog quantity input acquisition module is connected to the fifth current transformer (CT5); The fifth current transformer (CT5) is used to detect the current of the resistor (R); The second interface (BI02) of the switch quantity input acquisition module is connected to the temperature control switch (TJ) and is used to collect the state of the temperature control switch (TJ); The processing module (U) is used to calculate the accumulated heat of the resistor (R) according to the current of the resistor (R) when the temperature control switch (TJ) is in a closed state, and when the accumulated heat of the resistor (R) is greater than or equal to a preset heat threshold, send a tripping command to the circuit breaker (DL) through the fifth interface (BO05) of the output module, and after a delay of a preset time period, send a protection tripping signal to the fourth circuit breaker (DL4) through the fourth interface (BO04) of the output module.

8. A grounding protection method for a new energy power station, characterized in that: The grounding protection system applied to the new energy power station includes: The voltage transformer is used to detect the voltage of the busbar and send the voltage of the busbar to the grounding protection device, and the first current transformer is used to detect the current of the outgoing line and send the current of the outgoing line to the grounding protection device; The grounding protection device is used to collect the voltage of the busbar and the current of the outgoing line, perform amplitude and phase comparison, collect the closing / opening state of the circuit breaker, and judge whether a grounding fault occurs on the grid side to which the outgoing line is connected, and obtain a first judgment result; generate a corresponding opening / closing instruction according to the first judgment result, and issue an opening / closing instruction to the circuit breaker; The circuit breaker performs corresponding opening / closing operations according to the opening / closing instruction.

9. An electronic device, characterized in that: include: at least one processor and memory; The memory stores computer-executable instructions; The at least one processor executes the computer-executable instructions stored in the memory, so that the at least one processor executes the new energy power station grounding protection method as described in claim 8.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer-executable instructions, and when the computer-executable instructions are executed by a processor, they are used to implement the new energy power station grounding protection method according to claim 8.

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