Earth protection systems, methods, electronic equipment, and storage media for new energy power plants.

Abstract

This application provides a grounding protection system, method, electronic equipment, and storage medium for a new energy power plant, relating to the field of new energy power system protection technology. The system comprises a grounding protection device, as well as a grounding transformer neutral point equipment, a first current transformer, and a voltage transformer. The voltage transformer is used to detect the voltage of the busbar, and the first current transformer is used to detect the current of the transmission line. The neutral point of the grounding transformer is sequentially grounded via an isolation switch, a circuit breaker, and a resistor. The grounding protection device collects the voltage of the busbar and the current of the transmission line, performs amplitude-phase comparison, collects the closed / open state of the circuit breaker, determines whether a grounding fault has occurred on the transmission network side to which the transmission line is connected, generates a corresponding open / close command, and controls the circuit breaker to perform the corresponding open / close operation according to the open / close command. By adopting the above method, there is no need to install additional equipment such as isolation transformers and secondary control panels, saving human and equipment resources.

Description

Technical Field

[0001] This application relates to the field of new energy power system protection technology, and particularly to a grounding protection system, method, electronic device, and storage medium for a new energy power plant.

Background Art

[0002] With the development of new energy, new energy measures such as carbon peak and carbon neutrality are gradually being implemented. For example, small-scale new energy power systems such as distributed wind power generation are reducing power transmission investment and losses by connecting to the neighboring power distribution network to achieve local consumption.

[0003] The grounding method of the power system is generally classified into an effective grounding method and a non-effective grounding method, and the non-effective grounding method is divided into a neutral non-grounding method, a neutral low-resistance grounding method, a neutral high-resistance grounding method, and a neutral resonance grounding method. Among these neutral point The non-grounding method is applicable to the 35 kV distribution network where the capacitive current in a single-phase grounding fault is less than 10 A and overhead transmission lines are the mainstream. In a new energy power plant, there are many 35 kV cables and the capacitive current is also large, so the low-resistance grounding method is widely used to achieve rapid interruption of the grounding fault. However, if a new energy power plant where the low-resistance grounding method is applied is directly connected to the 35 kV distribution network where the non-grounding method is applied, a problem of inconsistent grounding methods of the system neutral point will occur.

[0004] To solve this problem, in the prior art, it is necessary to newly introduce an insulating transformer with a voltage level of 35 / 35 kV and a connection method of YNd, and install secondary control panels such as related main transformer protection devices and main transformer measurement and control devices, which has the technical problems of high cost and increased consumption of human and equipment resources.

Summary of the Invention

Problems to be Solved by the Invention

[0005] This invention provides a grounding protection system, method, electronic equipment, and storage medium for new energy power plants, solving the problem of increased consumption of human and equipment resources due to the need to newly introduce equipment such as isolation transformers and secondary control panels because the grounding methods of new energy power plants and power distribution networks do not match in the prior art. [Means for solving the problem]

[0006] According to a first aspect of the present application, an earthing protection system for a new energy power plant is provided, comprising an earthing transformer neutral point equipment, a first current transformer, a voltage transformer, and an earthing protection device. The new energy power plant has multiple lines, each line including one busbar, one transmission line, and multiple branch lines, the branch lines and the transmission line are each connected to the busbar, the busbar is provided with the voltage transformer, the transmission line is provided with the first current transformer, the voltage transformer and the first current transformer are each connected to the earthing protection device. The voltage transformer is used to detect the voltage of the busbar, and the first current transformer is used to detect the current of the transmission line. The plurality of branch lines include a grounding transformer branch line equipped with a grounding transformer and a grounding transformer neutral point equipment, the grounding transformer neutral point equipment comprising sequentially connected insulating switches, circuit breakers and resistors, the busbar being connected to the high-voltage side of the grounding transformer, and the neutral point of the grounding transformer being grounded sequentially via the insulating switches, circuit breakers and resistors. The earthing protection device is used to collect the voltage of the busbar and the current of the transmission line, perform amplitude-phase comparison, collect the closed / open state of the circuit breaker, determine whether or not an earthing fault has occurred on the transmission network side to which the transmission line is connected, obtain a first determination result, generate a corresponding open / close command according to the first determination result, and transmit the open / close command to the circuit breaker. The circuit breaker performs the corresponding open / close operation in accordance with the open / close command.

[0007] Selectively, the earth protection device comprises a processing module, and analog quantity input acquisition modules, switching quantity input acquisition modules, and output modules, which are respectively connected to the processing module. The analog quantity input acquisition module comprises a first interface and a tenth interface, wherein the first interface is connected to the first current transformer, and the tenth interface is connected to the voltage transformer. The switching amount input collection module comprises a first interface of the switching amount input collection module, the first interface of the switching amount input collection module is connected to the circuit breaker and is used to collect the closed / open state of the circuit breaker. The output module comprises a fifth interface and a sixth interface, the fifth interface of the output module being connected to the trip circuit of the circuit breaker and used to output an open command, and the sixth interface of the output module being connected to the close circuit of the circuit breaker and used to output a close command.

[0008] Selectively, the processing module comprises a first processing circuit and a second processing circuit connected in parallel, the output module comprises an output relay and a start relay, 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 becoming the fifth interface of the output module, and the sixth output relay becoming the sixth interface of the output module. The first processing circuit comprises a first analog / digital conversion module and a first processor connected sequentially, and the second processing circuit comprises a second analog / digital conversion module and a second processor connected sequentially. The first processor is connected to the first output relay, the second output relay, the third output relay, the fourth output relay, the fifth output relay, and the sixth output relay, respectively, and the second processor is connected to the startup relay. The startup relay controls whether or not to turn on the positive power supply of the output relay.

[0009] Selectively, the plurality of branch lines further include a current collector line and an SVG (Static Var Generator) line, wherein a second current transformer is provided in the current collector line, a third current transformer is provided in the SVG line, and a fourth current transformer is provided between the grounding transformer and the busbar in the grounding transformer branch line. The second current transformer, the third current transformer, and the fourth current transformer are used to detect the current of the current collection line, the current of the SVG line, and the current of the grounding transformer branch line, respectively. The earthing protection device, when the circuit breaker is in an open state, performs a threshold comparison with the voltage of the busbar, and the voltage of the busbar The place If the value exceeds a certain threshold, calculations and amplitude-phase comparisons are performed on the voltage of the busbar, the current of the transmission line, the current of the current collection line, the current of the SVG line, and the current of the grounding transformer branch line to determine whether or not a grounding fault has occurred in the busbar, and a second determination result is obtained. The grounding protection device, when the circuit breaker is open, performs a threshold comparison with the voltage of the busbar, and if the voltage of the busbar is equal to or greater than the predetermined threshold, performs calculations and amplitude-phase comparisons with the voltage of the busbar and the current of the current collector to determine whether or not a grounding fault has occurred in the current collector, and obtains a third determination result. The earth protection device, when the circuit breaker is open, performs a threshold comparison with the voltage of the busbar, and if the voltage of the busbar is equal to or greater than the predetermined threshold, performs calculations and amplitude-phase comparisons with the voltage of the busbar and the current of the SVG line to determine whether or not an earth fault has occurred in the SVG line, and obtains a fourth determination result. The earth protection device, when the circuit breaker is open, performs a threshold comparison with the voltage of the busbar, and if the voltage of the busbar is equal to or greater than the predetermined threshold, performs calculations and amplitude-phase comparisons with the voltage of the busbar and the current of the earthing transformer branch line to determine whether or not an earthing fault has occurred in the earthing transformer branch line and obtains a fifth determination result.

[0010] Optionally, the analog quantity input acquisition module further comprises a second interface, a third interface, and a fourth interface. The second interface of the analog quantity input acquisition module is connected to the second current transformer. The third interface of the analog quantity input acquisition module is connected to the third current transformer. The fourth interface of the analog quantity input acquisition module is connected to the fourth current transformer.

[0011] Selectively, the output module further comprises a first interface, a second interface, a third interface, and a fourth interface, wherein the first interface is a first output relay, the second interface is a second output relay, the third interface is a third output relay, and the fourth interface is a fourth output relay. A first circuit breaker is further provided in the transmission line, located between the first current transformer and the busbar, and the trip circuit of the first circuit breaker is connected to the first interface of the output module. A second circuit breaker is further provided in the current collection line, located between the second current transformer and the busbar, and the trip circuit of the second circuit breaker is connected to the second interface of the output module. In the SVG line, a third circuit breaker is further provided, located between the third current transformer and the busbar, and the trip circuit of the third circuit breaker is connected to the third interface of the output module. In the grounding transformer branch line, a fourth circuit breaker is further provided, located between the fourth current transformer and the busbar, and the trip circuit of the fourth circuit breaker is connected to the fourth interface of the output module. The processing module is used to transmit protective trip signals to the first circuit breaker, the second circuit breaker, the third circuit breaker, and the fourth circuit breaker via the first interface, the second interface, the third interface, and the fourth interface of the output module, respectively, when the second determination result is a bus fault. The processing module is further used to transmit a protective trip signal to the second circuit breaker via the second interface of the output module when the third determination result is a power collection line fault. The processing module is further used to transmit a protective trip signal to the third circuit breaker via the third interface of the output module when the fourth determination result is a fault in the SVG line. The processing module is further used to transmit a protective trip signal to the fourth circuit breaker via the fourth interface of the output module when the fifth determination result is a fault in the earthing transformer branch line.

[0012] Optionally, the system further comprises a fifth current transformer located between the resistor and ground, and a temperature control switch in the resistor chamber where the resistor is located. The analog quantity input acquisition module further has a fifth interface, the fifth interface of the analog quantity input acquisition module is connected to the fifth current transformer, The fifth current transformer is used to detect the current in the resistor. The second interface of the switching amount input collection module is connected to the temperature control switch and is used to collect the state of the temperature control switch. When the temperature control switch is in the closed state, the processing module calculates the cumulative heat amount of the resistor according to the current of the resistor. When the cumulative heat amount of the resistor is greater than or equal to a predetermined heat amount threshold, an open circuit command (that is, instantaneously operates the circuit breaker DL to switch to the open circuit state) is sent to the circuit breaker through the fifth interface of the output module, and after a predetermined time delay, a protection trip signal is sent to the fourth circuit breaker through the fourth interface of the output module.

[0013] According to the second aspect of the present application, a grounding protection method for a new energy power plant applied to the grounding protection system of the new energy power plant is provided. The grounding protection method for the new energy power plant is as follows: The voltage transformer detects the voltage of the bus and sends the voltage of the bus to the grounding protection device. The first current transformer detects the current of the transmission line and sends the current of the transmission line to the grounding protection device. <000,0086>]END]]The grounding protection device collects the voltage of the bus and the current of the transmission line, performs amplitude-phase comparison, collects the closed / open state of the circuit breaker, determines whether a grounding fault has occurred on the power grid side to which the transmission line is connected, obtains a first determination result, generates a corresponding open / closed circuit command according to the first determination result, and sends an open / closed circuit command to the circuit breaker, and The circuit breaker executes a corresponding open / closed circuit operation according to the open / closed circuit command.

[0014] According to the third aspect of the present application, an electronic device including at least one processor and a memory is provided. The memory stores computer-executable instructions. By executing the computer-executable instructions stored in the memory, the at least one processor executes the grounding protection method for the new energy power plant described in the second aspect above.

[0015] According to a fourth aspect of the present application, a computer-readable storage medium is provided, on which computer-executable instructions are stored. When the computer-executable instructions are executed by a processor, the grounding protection method for a new energy power plant described in the second aspect above is implemented.

[0016] According to a fifth aspect of the present application, a computer program product including a computer program is provided. When the computer program is executed by a processor, the grounding protection method for a new energy power plant described in the second aspect is implemented.

Advantages of the Invention

[0017] The grounding protection system for a new energy power plant according to the present application includes a grounding transformer neutral point facility, a first current transformer, a voltage transformer, and a grounding protection device. The new energy power plant has a plurality of lines, and the plurality of lines include one busbar, one transmission line, and a plurality of branch lines. The branch lines 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, and the first current transformer is used to detect the current of the transmission line. The plurality of branch lines include grounding transformer branch lines provided with a grounding transformer and a grounding transformer neutral point facility. The grounding transformer neutral point facility includes an insulating 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 insulating switch, the circuit breaker, and the resistor in sequence. The grounding protection device is used to collect the voltage of the busbar and the current of the transmission line, perform amplitude-phase comparison, collect the closed / open state of the circuit breaker, determine whether a grounding fault has occurred on the power grid side where the transmission line is connected, obtain a first determination result, generate a corresponding open / closed command according to the first determination result, transmit the open / closed command to the circuit breaker, and the circuit breaker executes a corresponding open / closed operation according to the open / closed command.

[0018] This invention enables control over whether or not the neutral point of the grounding transformer in the grounding transformer branch line is grounded, by having the grounding protection device control the circuit breaker in the grounding transformer neutral point equipment to perform a closing / open operation when the branch line and transmission line are connected to the busbar of the new energy power plant. In other words, it enables switching between resistance grounding and ungrounding methods of the grounding protection system. Therefore, the grounding protection system for new energy power plants according to this invention combines the advantages of both ungrounding and low-resistance grounding methods, satisfying the requirement that the distribution network can operate for 1-2 hours with a grounding fault in an ungrounded manner to ensure the continuity of power supply, while also satisfying the requirement that the new energy power plant can quickly shut off the grounding fault. Furthermore, this system is a neutral point self-adaptive grounding system in which the new energy power plant is directly connected to the distribution network, eliminating the need to install additional equipment such as isolation transformers and secondary control panels, thus saving human and equipment resources.

[0019] Furthermore, the contents described in this section are not intended to identify the main or important features of the embodiments of the present application, nor do they limit the scope of the present application. Other features of the present application will be readily apparent through the following description. [Brief explanation of the drawing]

[0020] The attached drawings are incorporated into the specification and constitute part of this specification. They illustrate embodiments suitable for the present application and, together with this specification, illustrate the principles of the present application. [Figure 1] This is a schematic diagram of the structure of a grounding protection system for a new energy power plant according to an embodiment of the present invention. [Figure 2] This is a schematic diagram of the structure of a grounding protection system for another new energy power plant according to an embodiment of the present invention. [Figure 3] This is a schematic diagram of the structure of an earthing protection device according to an embodiment of the present invention. [Figure 4] This is a schematic diagram of the structure of a grounding protection system for another new energy power plant according to an embodiment of the present invention. [Figure 5]This is a schematic diagram of a grounding transformer and grounding transformer neutral point equipment for a new energy power plant according to an embodiment of the present invention. [Figure 6] This is a flowchart of the grounding protection method for a new energy power plant according to the embodiment of the present invention. [Figure 7] This is a schematic diagram of the structure of an electronic device according to an embodiment of the present application. Clear embodiments of the present application are shown through the above drawings, and a detailed explanation will be given below. These drawings and textual descriptions are not intended to limit the scope of the concept of the present application in any way, but are provided as a reference for those skilled in the art to understand the concept of the present application by referring to specific embodiments. [Modes for carrying out the invention]

[0021] Here, the exemplary embodiments illustrated in the drawings are described in detail. In the following description, unless otherwise noted, the same numbers in different drawings refer to the same or similar elements. The embodiments described in the following exemplary embodiments are not representative of all embodiments consistent with the present application.

[0022] Grounding methods for power systems are generally classified into effective grounding methods and non-effective grounding methods. Non-effective grounding methods are further divided into neutral point ungrounding methods, neutral point low-resistance grounding methods, neutral point high-resistance grounding methods, and neutral point resonant grounding methods. Of these, the non-grounding method is applied when the capacitive current in a single-phase grounding fault is less than 10A, when the instantaneous single-phase grounding fault rate accounts for 60% to 70% in 35kV distribution networks where overhead transmission lines are the mainstream, and when it is desired that instantaneous grounding faults do not cause tripping. Its characteristics are as follows: When the capacitive current in a single-phase grounding fault is less than 10A, the arc at the fault point extinguishes naturally, and the insulation at the fault point automatically recovers after the arc is extinguished. Single-phase grounding does not impair the symmetry of the system, and operation is possible for 1 to 2 hours even with a fault condition, ensuring the continuity of power supply. Furthermore, this non-grounding method has less communication interference and is suitable for areas with many locations, widely dispersed, and complex user configurations, thus significantly improving the reliability of power supply.

[0023] On the other hand, new energy power plants often use 35kV cables and have large capacitive currents, so low-resistance grounding systems are frequently used to quickly shut off ground faults.

[0024] However, when a new energy power plant using a low-resistance grounding system is directly connected to a 35kV distribution network using an ungrounded system, a problem arises: a mismatch in the grounding method of the system neutral point. To solve this problem, conventional technology requires the introduction of a new isolation transformer with a voltage level of 35 / 35kV and a YNd connection method, along with the installation of a secondary control panel including a main transformer protection device and a main transformer measurement and control device. This presents technical problems such as high costs and increased consumption of human and equipment resources.

[0025] To solve the above technical problems, this application was conceived as part of an investigation into how to construct an earthing protection system for new energy power plants that is applicable to the protection area of ​​new energy power systems, combines the advantages of ungrounded and low-resistance grounding methods, and does not require the additional installation of equipment such as isolation transformers and secondary control panels.

[0026] The following will describe in detail, using specific examples, the technical solutions of the present application and how the above technical problems are solved using these solutions. The following specific examples can be combined and implemented, and some examples may not repeatedly describe the same or similar concepts or processes. The following examples of the present application will be described with reference to the drawings.

[0027] Example 1

[0028] Figure 1 is a schematic diagram of the structure of a grounding protection system for a new energy power plant according to an embodiment of the present invention. As shown in Figure 1, the grounding protection system for the new energy power plant comprises a grounding transformer neutral point equipment 10, a first current transformer CT1, a voltage transformer PT, and a grounding protection device 20.

[0029] The new energy power plant has multiple lines, which include one busbar L1, one transmission line L2, and multiple branch lines L3. The branch lines L3 and transmission line L2 are each 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 each connected to an earthing protection device 20.

[0030] In the embodiments of the present invention, the busbar L1 may be a 35kV busbar, one side of the transmission line L2 may be connected to the busbar L1, and the other side of the transmission line L2 may be connected to a 35kV distribution network or a distribution network of another voltage value. The embodiments of the present invention do not specifically limit the voltage value to which the distribution network is connected.

[0031] The voltage transformer PT is used to detect the voltage of the busbar L1, and the first current transformer CT1 is used to detect the current of the transmission line L2.

[0032] It should be understood that the voltage of busbar L1 is the open-circuit triangular voltage of the 35kV busbar collected by the voltage transformer PT, also called the 35kV busbar zero-sequence voltage, and can be denoted as 3U0. Also, transmission line L2 is also called a transmission line or 35kV transmission line. The first current transformer CT1 is a zero-sequence current transformer in the 35kV transmission line, and the current of transmission line L2 detected by it is also called the transmission line zero-sequence current, and can be denoted as 3I01.

[0033] Multiple branch lines L3 include a grounding transformer branch line L31 equipped with a grounding transformer T and a grounding transformer neutral point equipment 10. The grounding transformer neutral point equipment 10 comprises sequentially connected insulating switches GL, circuit breakers DL and resistors R, with the busbar connected to the high-voltage side of the grounding transformer T, and the neutral point of the grounding transformer T is grounded sequentially via the insulating switches GL, circuit breakers DL and resistors R.

[0034] In the embodiment of this application, the grounding transformer T has a ZNyn type connection and can be a 35kV grounding transformer. The grounding transformer T also functions as a service transformer and is also called a grounding / service transformer. In the ZNyn type, Z indicates that the primary winding is Z-type connected, y indicates that the secondary winding is star-type connected, and N and n indicate the drawn-out neutral wire. The insulating switch GL is also called an insulating breaker. The circuit breaker DL can be understood as a grounding transformer neutral point circuit breaker and is also called a 35kV grounding transformer neutral point circuit breaker. The type of circuit breaker DL may be a vacuum circuit breaker or another type of circuit breaker, and the embodiment of this application does not specifically limit it. The resistance R is a low resistance and is also called a 35kV grounding transformer neutral point resistance, and the embodiment of this application does not specifically limit its resistance value.

[0035] The grounding protection device 20 collects the voltage of the busbar L1 and the current of the transmission line L2, performs amplitude-phase comparison, collects the closed / open state of the circuit breaker DL, determines whether or not a grounding fault has occurred on the transmission network side to which the transmission line L2 is connected, obtains a first determination result, generates a corresponding open / close command according to the first determination result, and transmits the open / close command to the circuit breaker DL.

[0036] In the embodiments of the present application, the earth protection device 20 can collect the voltage of the busbar L1 and then perform a threshold comparison with respect to the voltage of the busbar L1, wherein a predetermined threshold is set to Uset, the threshold comparison is performed by one processor in the earth protection device 20, and the calculation and amplitude phase comparison are performed by the other processor in the earth protection device 20. Furthermore, the embodiments of the present application do not specifically limit the structure of the earth protection device 20.

[0037] Circuit breaker DL performs the corresponding open / close operation according to the open / close command.

[0038] Based on a 35kV busbar from a new energy power plant, the embodiment of this invention uses a ZNyn type grounding transformer to configure a zero-sequence impedance network in the event of a grounding fault. The grounding protection device 20 controls the circuit breaker DL according to the judgment criteria and controls the conduction / interruption of the zero-sequence impedance network in the event of a grounding fault by switching between the resistance grounding method and the ungrounded method of the grounding protection system.

[0039] In the embodiments of this invention, the ground fault types include ground faults on the power grid side to which the transmission line L2 is connected (or referred to as an out-of-area single-phase ground fault). The ground protection device 20 can determine whether or not a fault of this type has occurred based on the determination conditions for a ground fault of this type, which is a ground fault on the power grid side to which the transmission line L2 is connected. The determination conditions for a ground fault of this type, which is a ground fault on the power grid side to which the transmission line L2 is connected, are the 35kV bus zero-sequence voltage TIFF0007895026000002.tif25107, TIFF0007895026000003.tif38140, 3I01 ≥ the predetermined current value Iset.

[0040] In a specific example, the grounding protection device 20 can perform a threshold comparison with the 35kV bus zero-sequence voltage 3U0 and then decide whether or not to perform the determination of the remaining two conditions according to the threshold comparison result. That is, if 3U0 ≤ Uset, it is not necessary to perform the determination of the remaining two conditions, and the first determination result can be determined to be that there is no grounding fault on the transmission grid side to which the transmission line L2 is connected, and there is no grounding fault at the new energy power plant (i.e., there is no grounding fault in the 35kV system). If 3U0 ≥ Uset, the grounding protection device 20 can continue to detect and compare the phase of the 35kV bus zero-sequence voltage and the transmission line zero-sequence current 3I01, and the phase comparison result If TIFF0007895026000004.tif4572 is obtained and both the phase comparison result and the transmission line zero-sequence current 3I01 satisfy the determination conditions for a ground fault of the type called a ground fault on the transmission grid side to which transmission line L2 is connected, then the first determination result is that a ground fault has occurred on the transmission grid side to which transmission line L2 is connected.

[0041] For a grounding fault of the transmission grid side to which transmission line L2 is connected, the corresponding control method involves the grounding protection device 20 sending an open-circuit command to circuit breaker DL, which then executes the open-circuit command, resulting in an open state (i.e., circuit breaker DL tripping and opening). This switches the grounding protection system of the new energy power plant from a low-resistance grounding method to an ungrounded method, effectively preventing overheating damage to the neutral point resistance of the 35kV grounding transformer caused by prolonged current flow. Please note that the open-circuit command is also called an open-circuit signal.

[0042] Different types of ground faults have different detection criteria, and different types of ground faults correspond to different control methods. In Example 1, the detection criteria and control method for a ground fault type, namely a ground fault on the power grid side to which transmission line L2 is connected, were explained in detail. For detailed explanations of other ground fault types, detection criteria for ground fault types, and control methods, please refer to Example 3 below, as they will not be explained again here.

[0043] Furthermore, in the embodiment of the present invention, it is possible to determine whether or not a fault has been recovered based on the fault recovery determination conditions, which are that the circuit breaker DL is in an open state and 3U0 ≤ Uset. The control method corresponding to fault recovery is a method in which the earthing protection device 20 sends a closing command to the circuit breaker DL after a time delay t, causing the circuit breaker DL to execute the closing command and switch from an open state to a closed state.

[0044] In the embodiments of this invention, a closing command is also called a closing signal.

[0045] In the embodiment of the present invention, by utilizing the grounding protection system of a new energy power plant connected to a 35kV distribution network, and with the branch line L3 and transmission line L2 connected to the busbar L1, the grounding protection device 20 controls the circuit breaker DL in the grounding transformer neutral point equipment 10 to perform a closing / opening operation, thereby enabling control over whether or not the neutral point of the grounding transformer T in the grounding transformer branch line L31 where the circuit breaker DL is located is grounded. In other words, it becomes possible to switch between the resistance grounding method and the ungrounded method of the new energy power plant's grounding protection system. Therefore, the grounding protection system for new energy power plants according to the present invention combines the advantages of both the ungrounded method and the low-resistance grounding method, satisfying the requirement that the distribution network can operate for 1-2 hours with a grounding fault in an ungrounded manner to ensure the continuity of power supply, while also satisfying the requirement that the new energy power plant can quickly shut off the grounding fault. Furthermore, this system is a neutral point self-adaptive grounding system in which the new energy power plant is directly connected to the power distribution network, eliminating the need to install additional equipment such as isolation transformers and secondary control panels. This saves investment in isolation transformers and related protection and measurement control devices, as well as the consumption of human and equipment resources.

[0046] The technical solution of this application will be described in more detail below using several specific examples based on the above-mentioned embodiments.

[0047] Example 2

[0048] Figure 2 is a schematic diagram of the structure of a grounding protection system for another new energy power plant according to an embodiment of the present invention. In this embodiment, the structure of the grounding protection device in the grounding protection system for a new energy power plant will be described in detail.

[0049] As shown in Figure 2, the earth protection device 20 comprises a processing module U, and analog quantity input collection module AI, switching quantity input collection module BI, and output module BO, which are respectively connected to the processing module U.

[0050] Please understand that the analog quantity input acquisition module AI is also called the AI ​​plugin, the switching quantity input acquisition module BI is also called the BI plugin, and the output module BO is also called the BO plugin or switching quantity output module.

[0051] The analog quantity input acquisition module AI comprises a first interface AI01 and a tenth interface AI10. The first interface AI01 is connected to the first current transformer CT1, and the tenth interface AI10 is connected to the voltage transformer PT.

[0052] In the embodiments of this application, the first interface AI01 of the analog quantity input acquisition module is an earth protection device analog quantity input port, and similarly, the other interfaces of the analog quantity input acquisition module AI are also earth protection device analog quantity input ports. From this, it can be understood that the analog quantity input acquisition module AI is used to acquire the voltage signal from the voltage transformer PT and the current signal from the first current transformer CT1 and convert them into low-voltage signals.

[0053] The switching amount input collection module BI is equipped with a first interface BI01, which is connected to the circuit breaker DL and used to collect the closed / open state of the circuit breaker DL. Therefore, the switching amount input collection module BI is used to collect the open state of the circuit breaker DL. situation It can be understood that it is used to collect data.

[0054] In the embodiments of this invention, both the first interface BI01 and the second interface BI02 of the switching amount input collection module are earth protection device switching amount input ports.

[0055] The output module BO is equipped with a fifth interface BO05 and a sixth interface BO06. The fifth interface BO05 is connected to the trip circuit of circuit breaker DL and is used to output an open command, while the sixth interface BO06 is connected to the close circuit of circuit breaker DL and is used to output a close command.

[0056] In the embodiments of the present invention, both the fifth interface BO05 and the sixth interface BO06 of the output module are earth protection device switching amount output ports, and similarly, the other interfaces of the output module BO are also earth protection device switching amount output ports. The output module BO is used to send open / close commands to circuit breakers DL and / or to send trip commands 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.

[0057] In the embodiment of the present invention, the earthing protection device 20 having the above structure can be used not only to control the open / closed state of the circuit breaker DL, but also to trip and open the first circuit breaker DL1, the second circuit breaker DL2, the third circuit breaker DL3, and the fourth circuit breaker DL4, enabling a rapid response in the event of a fault, and saving resources compared to the conventional technology, which would otherwise be required to install additional isolation transformers and related protection and measurement control devices.

[0058] In one possible implementation, as shown in Figure 3, the processing module U comprises a first processing circuit U1 and a second processing circuit U2 connected in parallel, and the output module BO comprises an output relay J1 and a start relay J2. 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 becomes the fifth interface BO05 of the output module, and the sixth output relay J16 becomes the sixth interface BO06 of the output module.

[0059] It should be understood that the condition in which the earth protection device 20 detects that the 35kV bus zero-sequence voltage 3U0 has exceeded a limit value can be used as a criterion for the earth protection device to turn on the positive power supply of the output relay J1 via the starting relay J2 and connect the output relay J1 to the positive power supply. The condition in which the earth protection device 20 detects that the 35kV bus zero-sequence voltage 3U0 has exceeded a limit value refers to the condition in which the 35kV bus zero-sequence voltage 3U0 is greater than or equal to a predetermined threshold (i.e., 3U0 ≥ Uset).

[0060] The first processing circuit U1 comprises a first analog-to-digital conversion module 21 and a first processor 22 that are sequentially connected, and the second processing circuit U2 comprises a second analog-to-digital conversion module 23 and a second processor 24 that are sequentially connected.

[0061] Please understand that both the first analog / digital conversion module 21 and the second analog / digital conversion module 23 can be analog / digital conversion A / D modules. The first processor 22 is a protection DSP. (Digital Signal Processor) Also known as a module, the second processor 24 is also called the boot DSP module.

[0062] The first analog-to-digital conversion module 21 converts the low-voltage signal collected by the analog quantity input acquisition module AI into a digital signal using A / D sample-and-hold and transmits it to the first processor 22. Similarly, the second analog-to-digital conversion module 23 converts the low-voltage signal collected by the analog quantity input acquisition module AI into a digital signal using A / D sample-and-hold and transmits it to the second processor 24.

[0063] The first processor 22 is 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, respectively.

[0064] In the embodiment of the present invention, the earth protection device 20 further comprises a power supply module. The power supply module is used to supply the necessary power to the earth protection device 20.

[0065] The second processor 24 is used to perform a fault detection process, primarily for threshold comparison. When at least one arbitrary type of ground fault is detected (i.e., all ground faults satisfy the condition 3U0≧Uset), it turns on the positive power supply of output relay J1 via the start relay J2, connecting output relay J1 to the positive power supply.

[0066] The first processor 22 is used to execute a protection logic calculation process, mainly performing calculations and amplitude-phase comparisons to determine the type of ground fault, and generating a control signal including the executing entity and instruction type according to the control method corresponding to the type of ground fault. This control signal drives the output relay J1 to send an open / close command to the circuit breaker DL, and / or sends a protection trip signal to at least one of the first circuit breaker DL1, second circuit breaker DL2, third circuit breaker DL3, and fourth circuit breaker DL4, thereby executing the instruction corresponding to the executing entity and completing the corresponding protection operation. Different types of ground faults have different determination conditions, and different types of ground faults correspond to different control methods. For a detailed explanation of all ground fault types, determination conditions for ground fault types, and control methods, please refer to Embodiment 1 above and Embodiment 3 below, as they will not be repeated here.

[0067] In one possible implementation, as shown in Figure 3, the earth protection device 20 further comprises 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 time synchronization module 27, and a human-machine interaction module 28 connected to the central processing unit.

[0068] The central processing unit 25 is also called the central processing unit CPU module, and the central processing unit 25 processes events in order. Introduction( Sequence of Events (SOE) record waveform recording, printing, time synchronization, provision of a human-machine interaction interface to the human-machine interaction module 28, and monitoring View( Supervisory Control and Data Acquisition (SCADA) system Please understand that this is used to enable communication with [the system / platform].

[0069] In other words, the grounding protection device 20 uploads its operating information and event sequence records to the SCADA monitoring system via a communication port, through a station control layer switch or remote control device, and the SCADA monitoring system's backend operators then monitor the new energy power plant and its grounding protection system.

[0070] The time synchronization module 27 uses GPS (Global positioning system) It should be understood that this can be a time synchronization module. The GPS time synchronization module controls the real-time synchronization of the data acquisition modules (i.e., the analog quantity input acquisition module AI and the switching quantity input acquisition module BI), the protection DSP module, and the startup DSP module, and is used to ensure that the protection logic calculation process and the data collected by the data acquisition module are executed simultaneously, as well as to ensure time synchronization of the grounding protection device 20, the SCADA monitoring system, and the scheduling system.

[0071] The human-machine interaction module 28 is used to query and modify commands, and by inputting relevant settings into the human-machine interaction module 28, the user can obtain the operating status of all equipment in the new energy power plant.

[0072] Furthermore, in the embodiment of the present invention, a protection information substation and a fault waveform recording device can also be installed, respectively connected to the grounding protection device 20. The grounding protection device 20 uploads fault information (including grounding fault type) corresponding to the protection operation to the protection information substation via a communication port. The protection information substation is used to collect fault information when a protection operation occurs in the grounding protection system of a new energy power plant and upload it to the scheduling system. The grounding protection device 20 outputs the switching amount of the protection operation to the fault waveform recording device via a switching amount output port. The fault waveform recording device records waveforms when the parameters exceed limit values ​​(e.g., 3U0≧Uset, 3I01≧Iset, etc.), when the switch position changes (i.e., when the state of at least one circuit breaker changes), and when a protection operation occurs.

[0073] In the embodiment of this invention, a new grounding protection system, namely a grounding protection system for new energy power plants, is proposed to address the problem of mismatch in neutral point grounding methods that arises when new energy power plants are connected to a 35kV distribution network. This system is a grounding protection system that utilizes the self-adaptation of the neutral point grounding method and combines the advantages of low-resistance grounding and ungrounded methods. As a result, it can operate for 1 to 2 hours even with a grounding fault, which is required for a 35kV distribution network, and satisfies the requirement of ensuring the continuity of power supply, while also satisfying the requirements of new energy power plants for rapid interruption of grounding faults and ensuring equipment safety.

[0074] Example 3

[0075] Figure 4 is a schematic diagram of the structure of an earthing protection system for another new energy power plant according to an embodiment of the present invention. As shown in Figure 4, the multiple branch lines L3 further include a current collector line L32 and an SVG line L33, a second current transformer CT2 is provided in the current collector line L32, a third current transformer CT3 is provided in the SVG line L33, and a fourth current transformer CT4 is provided between the earthing transformer T and the busbar L1 in the earthing transformer branch line L31. The number of current collector lines L32 may be one or multiple, and the embodiment of the present invention does not specifically limit the number.

[0076] The second current transformer CT2, the third current transformer CT3, and the fourth current transformer CT4 are used to detect the current in the current collection line L32, the current in the SVG line L33, and the current in the grounding transformer branch line L31, respectively.

[0077] The second current transformer CT2 is a zero-sequence current transformer in the collection line L32, and the detected current in the collection line L32 is also called the 35kV collection line zero-sequence current and can be denoted as 3I02. The third current transformer CT3 is a zero-sequence current transformer in the SVG line L33, and the detected current in the SVG line L33 is also called the 35kV SVG zero-sequence current and can be denoted as 3I03. The fourth current transformer CT4 is a zero-sequence current transformer in the grounding transformer branch line L31, and the detected current in the grounding transformer branch line L31 is also called the 35kV grounding transformer zero-sequence current and can be denoted as 3I04.

[0078] In the embodiment of the present invention, the grounding protection device 20 is further used to determine whether other grounding fault types exist, such as a busbar L1 grounding fault, a grounding transformer branch line L31 grounding fault, a collector line L32 grounding fault, or an SVG line L33 grounding fault, by combining 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, etc., when the neutral point resistance of the 35kV grounding transformer is operating without grounding. Specifically, the analysis is performed as follows.

[0079] When the circuit breaker DL is open, the grounding protection device 20 performs a threshold comparison with the voltage of the busbar L1. If the voltage of the busbar L1 is above a predetermined threshold, it performs calculations and amplitude-phase comparisons with the voltage of the busbar L1, the current of the transmission line L2, the current of the collection line L32, the current of the SVG line L33, and the current of the grounding transformer branch line L31 to determine whether or not a grounding fault has occurred in the busbar L1 and obtains a second determination result.

[0080] In the embodiments of this invention, the ground fault type includes a busbar L1 ground fault. The ground protection device 20 can determine whether or not a fault of this type has occurred based on the determination conditions for a busbar L1 ground fault. The determination conditions for a busbar L1 ground fault are 3U0≧Uset, TIFF0007895026000005.tif48167, TIFF0007895026000006.tif34118, TIFF0007895026000007.tif34117, TIFF0007895026000008.tif34118, circuit breaker DL is in the open state, 3I01 ≥ predetermined current value Iset, 3I02 ≥ predetermined current value Iset, 3I03 ≥ predetermined current value Iset, and 3I04 ≥ predetermined current value Iset.

[0081] In a specific example, the grounding protection device 20 can perform a threshold comparison against the 35kV bus zero-sequence voltage 3U0, collect the closed / open state of the circuit breaker DL, and then decide whether to perform the determination of the remaining eight conditions based on the threshold comparison result and the collected 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 the determination of the remaining eight conditions, and the second determination result can be known to be that no grounding fault has occurred on the bus L1. If 3U0 ≥ Uset and the circuit breaker DL is in the open state, the grounding protection device 20 then detects and compares the phases of the 35kV bus zero-sequence voltage, 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, and the phase comparison result TIFF0007895026000009.tif4163, TIFF0007895026000010.tif3858, TIFF0007895026000011.tif3959 and TIFF0007895026000012.tif4163 is obtained, and threshold comparisons can be performed on the zero-sequence current 3I01 of the transmission line, the zero-sequence current 3I02 of the 35kV collection line, the zero-sequence current 3I03 of the 35kV SVG, and the zero-sequence current 3I04 of the 35kV grounding transformer. If all phase comparison results and all threshold comparison results satisfy the criteria for determining a grounding fault of the type L1 grounding fault, then the second determination result is that a grounding fault has occurred on busbar L1.

[0082] For a ground fault of the busbar L1 type, the corresponding control method is as follows: In the ground protection device 20, the first output relay J11, the second output relay J12, the third output relay J13, and the fourth output relay J14 all operate after a time delay t, transmitting protective trip signals (abbreviated as trip commands) to the first circuit breaker DL1, the second circuit breaker DL2, the third circuit breaker DL3, and the fourth circuit breaker DL4, respectively. This causes the first circuit breaker DL1, the second circuit breaker DL2, the third circuit breaker DL3, and the fourth circuit breaker DL4 to execute the trip command, switching them to an open state (i.e., the first circuit breaker DL1, the second circuit breaker DL2, the third circuit breaker DL3, and the fourth circuit breaker DL4 trip and open), thereby insulating the fault point by tripping and opening all branch lines in the 35kV new energy power plant.

[0083] In the embodiments of the present invention, a busbar L1 ground fault is one type of ground fault. In addition to the transmission network-side fault to which the transmission line L2 is connected and the busbar L1 ground fault in Embodiment 1, the ground fault types in the embodiments of the present invention further include branch line faults such as a grounding transformer branch line L31 ground fault, a collector line L32 ground fault, and an SVG line L33 ground fault.

[0084] When the circuit breaker DL is open, the grounding protection device 20 performs a threshold comparison with the voltage of the busbar L1. If the voltage of the busbar L1 is above a predetermined threshold, it performs calculations and amplitude-phase comparisons with the voltage of the busbar L1 and the current of the current collector L32 to determine whether or not a grounding fault has occurred in the current collector L32, and obtains a third determination result.

[0085] In the embodiment of this application, the ground fault type includes branch line faults, and the branch line fault includes ground faults on the grounding transformer branch line L31, ground faults on the current collector line L32, and ground faults on the SVG line L33. For a current collector line L32 ground fault, the grounding protection device 20 can determine whether or not a fault of this type has occurred based on the determination conditions for a current collector line L32 ground fault. The determination conditions for a current collector line L32 ground fault are 3U0≧Uset, TIFF0007895026000013.tif35127, circuit breaker DL is in the open state, and 3I02 ≥ the specified current value Iset.

[0086] In a specific example, the earthing protection device 20 performs a threshold comparison with the 35kV bus zero-sequence voltage 3U0, collects the closed / open state of the circuit breaker DL, and then decides whether to perform the determination of the remaining two conditions based on the threshold comparison result and the collected 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 the determination of the remaining two conditions, and the third determination result is that no earthing fault has occurred in the collection line L32. If 3U0 ≥ Uset and the circuit breaker DL is in the open state, the earthing protection device 20 continues to detect and compare the phase of the 35kV bus zero-sequence voltage and the 35kV collection line zero-sequence current 3I02, and the phase comparison result TIFF0007895026000014.tif4366 is obtained, and a threshold comparison can be performed on the 35kV current collector zero-sequence current 3I02. If both the phase comparison result and the threshold comparison result satisfy the criteria for determining a ground fault of the type L32 current collector ground fault, then the third determination result is that a ground fault has occurred in the current collector L32.

[0087] For a ground fault of the current collection line L32, the corresponding control method is as follows: After a time delay t, the ground protection device 20 activates the second output relay J12, which transmits a protection trip signal to the second circuit breaker DL2. This causes the second circuit breaker DL2 to execute a trip command, switching it to an open state (i.e., the second circuit breaker DL2 trips and opens), thereby tripping and opening the fault line and insulating the fault point.

[0088] When the circuit breaker DL is open, the earthing protection device 20 performs a threshold comparison with the voltage of the busbar L1. If the voltage of the busbar L1 is above a predetermined threshold, it performs calculations and amplitude-phase comparisons with the voltage of the busbar L1 and the current of the SVG line L33 to determine whether or not an earthing fault has occurred in the SVG line L33, and obtains the fourth determination result.

[0089] In the embodiments of this application, the ground fault type includes branch line faults, and the branch line fault includes ground faults on the grounding transformer branch line L31, ground faults on the current collector line L32, and ground faults on the SVG line L33. For ground faults on the SVG line L33, the grounding protection device 20 can determine whether or not a fault of this type has occurred based on the determination conditions for ground faults of this type. The determination conditions for ground faults of this type, SVG line L33, are 3U0≧Uset, TIFF0007895026000015.tif37141, circuit breaker DL is in the open state, and 3I03 ≥ the specified current value Iset.

[0090] In a specific example, the earthing protection device 20 performs a threshold comparison with the 35kV bus zero-sequence voltage 3U0, collects the closed / open state of the circuit breaker DL, and then decides whether to perform the determination of the remaining two conditions based on the threshold comparison result and the collected 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 the determination of the remaining two conditions, and the fourth determination result can be determined to be that no earthing fault has occurred in the SVG line L33. If 3U0 ≥ Uset and the circuit breaker DL is in the open state, the earthing protection device 20 continues to detect and compare the phase of the 35kV bus zero-sequence voltage and the 35kV SVG zero-sequence current 3I03, and the phase comparison result If TIFF0007895026000016.tif5382 is obtained and a threshold comparison can be performed on the 35kV SVG zero-sequence current 3I03, and both the phase comparison result and the threshold comparison result satisfy the determination conditions for a ground fault of the type SVG line L33, then the fourth determination result is that a ground fault has occurred on the SVG line L33.

[0091] For a ground fault of the SVG line L33, the corresponding control method is as follows: After a time delay t, the ground protection device 20 activates the third output relay J13, which transmits a protection trip signal to the third circuit breaker DL3. This causes the third circuit breaker DL3 to execute a trip command, switching it to an open state (i.e., the third circuit breaker DL3 trips and opens), thereby tripping and opening the fault line and insulating the fault point.

[0092] When the circuit breaker DL is open, the earthing protection device 20 performs a threshold comparison with the voltage of the busbar L1. If the voltage of the busbar L1 is above a predetermined threshold, it performs calculations and amplitude-phase comparisons with the voltage of the busbar L1 and the current of the earthing transformer branch line L31 to determine whether or not an earthing fault has occurred in the earthing transformer branch line L31, and obtains the fifth determination result.

[0093] In the embodiments of this application, the ground fault type includes branch line faults, and the branch line fault includes ground faults on the grounding transformer branch line L31, ground faults on the current collector line L32, and ground faults on the SVG line L33. For a ground fault on the grounding transformer branch line L31, the grounding protection device 20 can determine whether or not a fault of this type has occurred based on the determination conditions for a ground fault of this type. ground fault The criteria for determining this type of ground fault is 3U0≧Uset. TIFF0007895026000017.tif32119, circuit breaker DL is in the open state, and 3I04 ≥ the specified current value Iset.

[0094] In a specific example, the grounding protection device 20 performs a threshold comparison with the 35kV bus zero-sequence voltage 3U0, collects the closed / open state of the circuit breaker DL, and then decides whether to perform the determination of the remaining two conditions based on the threshold comparison result and the collected 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 the determination of the remaining two conditions, and the fifth determination result can be determined to be that no grounding fault has occurred in the grounding transformer branch line L31. If 3U0 ≥ Uset and the circuit breaker DL is in the open state, the grounding protection device 20 continues to detect and compare the phase of the 35kV bus zero-sequence voltage and the 35kV grounding transformer zero-sequence current 3I04, and the phase comparison result If TIFF0007895026000018.tif3859 is obtained and a threshold comparison can be performed on the 35kV grounding transformer zero-sequence current 3I04, and both the phase comparison result and the threshold comparison result satisfy the determination conditions for a grounding fault of the type L31 grounding transformer branch line, then the fifth determination result is that a grounding fault has occurred in the L31 grounding transformer branch line.

[0095] For a grounding fault of the L31 branch line of the grounding transformer, the corresponding control method is as follows: After a time delay t, the fourth output relay J14 operates after the grounding protection device 20 has detonated, and sends a protective trip signal to the fourth circuit breaker DL4, causing the fourth circuit breaker DL4 to execute a trip command and switch to an open state (i.e., the fourth circuit breaker DL4 trips and opens), thereby tripping and opening the fault line and insulating the fault point.

[0096] In the embodiment of the present invention, when a grounding fault occurs in any branch line, the faulty branch line can be identified accurately and effectively, thereby improving the safety of the system.

[0097] In one possible implementation, as shown in Figure 4, the analog quantity input acquisition module AI further comprises a second interface AI02, a third interface AI03, and a fourth interface AI04, where the second interface AI02 is connected to the second current transformer CT2, the third interface AI03 is connected to the third current transformer CT3, and the fourth interface AI04 is connected to the fourth current transformer CT4.

[0098] The analog quantity input acquisition module AI is used not only to acquire the voltage signal from the voltage transformer PT and the current signal from the first current transformer CT1 and convert them into corresponding low-voltage signals, but also to acquire the current signals from the second current transformer CT2, the third current transformer CT3, and the fourth current transformer CT4 and convert them into corresponding low-voltage signals.

[0099] In the embodiment of this invention, the analog quantity input acquisition module AI is provided with corresponding interfaces for each current transformer and voltage transformer, and current and voltage can be collected to provide data evidence for accurate identification of fault type and fault line.

[0100] In one possible implementation, as is clear from Figures 1 to 4, the output module BO further comprises a first interface BO01, a second interface BO02, a third interface BO03, and a fourth interface BO04. The first interface BO01 becomes the first output relay J11, the second interface BO02 becomes the second output relay J12, the third interface BO03 becomes the third output relay J13, and the fourth interface BO04 becomes the fourth output relay J14.

[0101] In the transmission line L2, a first circuit breaker DL1 is further provided, located between the first current transformer CT1 and the busbar L1, and the trip circuit of the first circuit breaker DL1 is connected to the first interface BO01 of the output module.

[0102] A second circuit breaker DL2 is further provided on the current collection line L32, located between the second current transformer CT2 and the busbar L1, and the trip circuit of the second circuit breaker DL2 is connected to the second interface BO02 of the output module.

[0103] In the SVG line L33, a third circuit breaker DL3 is further provided, located between the third current transformer CT3 and the busbar L1, and the trip circuit of the third circuit breaker DL3 is connected to the third interface BO03 of the output module.

[0104] In the grounding transformer branch line L31, a fourth circuit breaker DL4 is further provided, located between the fourth current transformer CT4 and the busbar L1, and the trip circuit of the fourth circuit breaker DL4 is connected to the fourth interface BO04 of the output module.

[0105] Processing module U is used to transmit protective trip signals to the first circuit breaker DL1, the second circuit breaker DL2, the third circuit breaker DL3, and the fourth circuit breaker DL4 via the first interface BO01, the second interface BO02, the third interface BO03, and the fourth module BO04 of the output module, respectively, when the second determination result indicates that a ground fault has occurred on busbar L1. The description of the technical solution in this section is a detailed description of the control method for a ground fault type, namely a busbar L1 ground fault.

[0106] The processing module U is further used to send a protection trip signal to the second circuit breaker DL2 via the output module's second interface BO02 if the third determination result indicates that a ground fault has occurred in the current collection line L32.

[0107] The protective trip signal is also called an open-circuit command. The explanation of the technical solution in this section is a detailed explanation of the control method for a ground fault type called a current collector line L32 ground fault.

[0108] The processing module U is further used to transmit a protective trip signal to the third circuit breaker DL3 via the output module's third interface BO03 if the fourth determination result indicates that a ground fault has occurred on the SVG line L33. The description of the technical solution in this part is a detailed description of the control method for the ground fault type of SVG line L33 ground fault.

[0109] The processing module U is further used to transmit 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 that a ground fault has occurred in the grounding transformer branch line L31. The description of the technical solution in this part is a detailed description of the control method for the ground fault type of ground fault, which is a ground fault in the grounding transformer branch line L31.

[0110] As is clear from the above description, the output module BO is used not only to send open / close commands to circuit breakers DL, but also to send protective trip signals 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.

[0111] In the embodiment of this invention, the output module BO provides a corresponding interface to each circuit breaker, enabling accurate implementation of the control method and providing support for fault isolation and system safety.

[0112] In one possible implementation, as shown in Figure 4, the system further comprises a fifth current transformer CT5 located between the resistor R and the ground, and a temperature control switch TJ in the resistor chamber where the resistor R is located.

[0113] The switching amount includes input and output amounts, is a digital signal, has only two states, 0 and 1, representing the open and closed states of a relay contact, respectively. Therefore, the temperature control switch TJ can be understood as the overheated contact of the temperature controller within a 35kV grounding transformer resistor cabinet, and it should be understood that it switches from the open state to the closed state after exceeding a predetermined temperature threshold.

[0114] As shown in Figure 5, the resistance room 300, transformer room 100, and operating electrical room 200 constitute a 35kV grounding transformer resistance cabinet (abbreviated as grounding transformer resistance cabinet). A resistor R, a fifth current transformer CT5, and a temperature control switch TJ are installed in the resistance room 300. The temperature control switch TJ can be installed in the cabinet body of the resistance room 300. A grounding transformer T is installed in the transformer room 100. In addition, the above-mentioned isolation switch GL and circuit breaker DL are installed in the operating electrical room 200.

[0115] The operating room 200 is further equipped with a closing indicator light and an opening indicator light for the circuit breaker DL, used for closing and opening indications, respectively. The operating room 200 is also equipped with a closing button and an opening button for the circuit breaker DL to facilitate manual operation by the user. Furthermore, the operating handle for the insulating switch GL, used for opening and closing operations of the insulating switch GL, is also installed in the operating room 200. It should be understood that the operating room 200 is also referred to as the switch room.

[0116] Furthermore, in addition to the installation of a corresponding branch line integrated protection measurement and control device on the grounding transformer branch line L31, corresponding branch line integrated protection measurement and control devices are also installed on the current collection line L32 and the SVG line L33.

[0117] The analog quantity input acquisition module AI is further equipped with a fifth interface AI05, which is connected to the fifth current transformer CT5.

[0118] The fifth current transformer CT5 is used to detect the current through resistor R. The fifth current transformer CT5 is the current transformer at the neutral point of the grounding transformer, and the detected current at the neutral point of the grounding transformer can be expressed as 3I05.

[0119] The second interface BI02 of the switching amount input acquisition module is connected to the temperature control switch TJ and is used to acquire the state of the temperature control switch TJ. From this, it can be understood that the switching amount input acquisition module BI is used not only to acquire the open position of the circuit breaker DL, but also to acquire the switching amount signal of the temperature control switch TJ.

[0120] When the temperature control switch TJ is closed, the processing module U calculates the cumulative heat (3I05) through resistor R according to the current through resistor R. 2 Calculate t and the cumulative heat of resistance R (3I05) 2 t is a predetermined heat threshold Q setIn the above case, an open-circuit command is sent to circuit breaker DL via the fifth interface BO05 of the output module, and after a predetermined time delay, a protection trip signal is sent to the fourth circuit breaker DL4 via the fourth interface BO04 of the output module.

[0121] In the embodiment of this application, in addition to grounding fault types such as transmission line L2 fault, busbar L1 grounding fault, grounding transformer branch line L31 grounding fault, collector line L32 grounding fault, and SVG line L33, an actual fault (i.e., a fault due to the malfunction of circuit breaker DL) is also defined. For actual faults, the determination condition is 3U0≧Uset, TIFF0007895026000019.tif3095 and the temperature control switch TJ is in the closed state, and the control method is such that the 5th output relay J15 operates and sends an open command to the circuit breaker DL again, and after a time delay t, the 6th output relay J16 operates and sends a protective trip signal to the 4th circuit breaker DL4.

[0122] In the embodiments of this invention, it is possible to switch between resistance grounding and ungrounding methods of the grounding protection system in various situations. Therefore, the grounding protection system for new energy power plants according to this invention combines the advantages of both ungrounding and low-resistance grounding methods, satisfying the requirement that the distribution network can operate for 1-2 hours with an ungrounding fault and ensure the continuity of power supply, while also satisfying the requirement that the new energy power plant can quickly shut off the grounding fault.

[0123] As is clear from Figure 4, the earthing protection system for a new energy power plant connected to a 35kV distribution network according to the embodiment of the present invention has a single earthing transformer T connected to the 35kV bus of the new energy power plant so that the neutral point is earthed sequentially via an insulating switch GL, a circuit breaker DL, and a resistor R, and a fifth current transformer CT5 is installed at the earthing terminal of the resistor R. The 35kV bus zero-sequence voltage 3U0 detected by the voltage transformer PT on the 35kV bus is provided to the 10th interface AI10 of the analog quantity input collection module; the transmission line zero-sequence current 3I01 is provided to the 1st interface AI01 of the analog quantity input collection module; the 35kV collector zero-sequence current 3I02 is provided to the 2nd interface AI02 of the analog quantity input collection module; the 35kV SVG zero-sequence current 3I03 is provided to the 3rd interface AI03 of the analog quantity input collection module; the 35kV grounding transformer zero-sequence current 3I04 is provided to the 4th interface AI04 of the analog quantity input collection module; and the grounding transformer neutral point current 3I05 is provided to the 5th interface AI05 of the analog quantity input collection module. The trip 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 trip circuit of the second circuit breaker DL2 located on the collection line L32 is connected to the second interface BO02 of the output module, the trip 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 trip circuit of the fourth circuit breaker DL4 located on the grounding transformer branch line L31 is connected to the fourth interface BO04 of the output module, the trip circuit of circuit breaker DL is connected to the fifth interface BO05 of the output module, the closed circuit of circuit breaker DL is connected to the sixth interface BO06 of the output module, and the open circuit of circuit breaker DL is connected circuit The first interface BI01 of the switching amount input collection module is connected to the temperature control switch TJ, and the second interface BI02 of the switching amount input collection module is connected to the temperature control switch TJ.

[0124] Example 4

[0125] Figure 6 is a flowchart of a ground protection method for a new energy power plant according to an embodiment of the present invention. As shown in Figure 6, the method in this embodiment is applicable to a ground protection system for a new energy power plant according to any one of the embodiments of Embodiments 1 to 3, and the method in this embodiment includes steps S10 to S30.

[0126] In S10, the voltage transformer detects the busbar voltage and transmits the busbar voltage to the earthing protection device, and the first current transformer detects the transmission line current and transmits the transmission line current to the earthing protection device.

[0127] In S20, the grounding protection device collects the voltage of the busbar and the current of the transmission line, performs amplitude-phase comparison, collects the closed / open state of the circuit breaker, determines whether or not a grounding fault has occurred on the transmission network side to which the transmission line is connected, obtains a first determination result, generates a corresponding open / close command according to the first determination result, and transmits the open / close command to the circuit breaker.

[0128] In S30, the circuit breaker performs the corresponding open / close operation according to the open / close command.

[0129] The embodiments of this application analyze the method as follows, depending on the change in the situation.

[0130] (1) Under normal operation, the neutral point of the 35kV distribution network is ungrounded, and the neutral point of the new energy power plant connected to the 35kV distribution network is low-resistance grounded.

[0131] (2) If a single-phase ground fault occurs within the area (outside the area refers to the 35kV distribution network connected to the transmission line) while the new energy power plant is operating under normal conditions, the zero-sequence current will increase because the neutral point of the new energy power plant is operating under low-resistance grounding.

[0132] If the fault is located on a transmission line, the differential protection of the transmission line circuit activates to shut off the fault. If the fault is located on a 35kV busbar within a new energy power plant, the differential protection of the 35kV busbar activates to shut off the fault. If the fault is located on a collector line, SVG line, or grounding transformer branch line within a new energy power plant, the corresponding branch line integrated protection instrumentation control unit activates to shut off the fault. In addition, grounding transformer zero-phase protection functions as remote backup protection against collector line grounding faults and SVG line grounding faults.

[0133] (3) If an out-of-area single-phase grounding fault occurs while a new energy power plant is operating normally, the zero-sequence current will be large because the neutral point of the new energy power plant is operating under low-resistance grounding, which facilitates accurate fault line selection in the 35kV distribution network. Furthermore, by detecting and comparing the phase of the 35kV bus zero-sequence voltage 3U0 and the transmission line zero-sequence current 3I01, the grounding protection device sends an open signal to the circuit breaker DL, causing the circuit breaker DL to trip and open, switching the new energy power plant from a low-resistance grounding system to an ungrounded system.

[0134] To prevent malfunction of circuit breaker DL and overheating damage to the neutral point resistance of the 35kV grounding transformer due to prolonged current flow, 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, performs a heat accumulation calculation, and if a malfunction occurs, instantly trips circuit breaker DL again, activates the fourth circuit breaker DL4 after a delay time t, and trips the fourth circuit breaker DL4, thereby ensuring a double layer of operational safety for new energy power plants employing a low-resistance grounding system.

[0135] (4) When an out-of-area single-phase ground fault occurs at a new energy power plant, and a single-phase ground fault of the same phase also occurs simultaneously within the area, the fault current becomes a system capacitive current because the neutral point at the new energy power plant is operating ungrounded, and the fault current is split between the out-of-area and in-area fault ground points. By comparing the amplitude and phase of the zero-sequence voltage and zero-sequence current at the in-area fault branch line, it can be determined that the comparison results satisfy the operating conditions, and the ground protection device will operate and transmit a protective trip signal corresponding to the fault branch line, tripping the fault branch line and isolating the fault point. For example, if the fault point of a single-phase ground fault of the same phase within the area is on the 35kV busbar, collector line, SVG line, or grounding transformer branch line at the new energy power plant, the ground protection device will operate and shut off the fault.

[0136] When an out-of-zone single-phase grounding fault occurs at a new energy power plant, and a different-phase single-phase grounding fault also occurs simultaneously within the same zone, this is equivalent to a two-phase short-circuit grounding. The corresponding branch line integrated protection measurement and control device can perform overcurrent protection to shut off the fault, and at the same time, the grounding protection device can function as a backup protection device and operate to shut off the fault.

[0137] (5) If a new energy power plant recovers after a certain period of time has elapsed following an out-of-area single-phase grounding fault, and the 35kV bus zero-sequence voltage 3U0 returns to exceed the limit value, the grounding protection device will send a closing command to the circuit breaker DL after a delay time t, thereby switching the new energy power plant from an ungrounded system to a low-resistance grounding system.

[0138] As described above, the embodiment of this application performs fault detection within and outside the zone by comparing the amplitude of zero-sequence voltage and zero-sequence current and by phase comparison, and detects operation when the 35kV bus zero-sequence voltage 3U0 exceeds the limit value. Based on the return, Out-of-area fault occurrence / resolution of discrimination deathThis enables the automatic switching of the neutral point grounding system in a new energy power plant by performing DL circuit breaker open / close operations. In this embodiment, when an in-area fault occurs during an out-of-area fault, the accuracy of line selection tripping can be improved by comparing the amplitudes of zero-sequence voltage and zero-sequence current and by comparing phases. The beneficial effects of this embodiment are as follows: (1) It combines the advantages of both ungrounded and low-resistance grounding systems, enabling the construction of a neutral point self-adaptive grounding system connected to a new energy power plant in a distribution network. (2) It saves resource input associated with the additional installation of isolation transformers and related protection and measurement control devices.

[0139] The grounding protection method for new energy power plants according to this embodiment will not be explained again here, as its implementation principle and technical effects are similar to those of the grounding protection system for new energy power plants according to the embodiment of the system described above.

[0140] Furthermore, all user information and data involved in this application (including, but not limited to, data for analysis, storage, and display) are information and data for which the user's permission or sufficient permission from all relevant parties has been obtained. The collection, use, and processing of the relevant data comply with the relevant laws, regulations, and standards of the relevant countries and regions, and a corresponding operating interface is provided that allows the user to choose to permit or deny access. In other words, in the technical solution of this application, the collection, storage, use, processing, transmission, provision, and disclosure of relevant user personal information all comply with the provisions of relevant laws and regulations and do not violate public order and morals.

[0141] According to embodiments of the present application, the present application further provides electronic equipment and a readable storage medium.

[0142] Figure 7 is a schematic diagram of the structure of an electronic device according to an embodiment of the present application. The electronic device comprises a receiver 70, a transmitter 71, at least one processor 72, and memory 73, and the electronic device consisting of the above components can be used to carry out some of the above specific embodiments of the present application, which will not be repeated here.

[0143] Embodiments of the present invention further provide a computer-readable storage medium in which computer execution instructions are stored, and each step of the method in the above embodiment is implemented when a processor executes the computer execution instructions.

[0144] Embodiments of the present invention further provide a computer program product comprising a computer program, wherein each step of the method in the above embodiment is implemented when the computer program is executed by a processor.

[0145] Various embodiments of the systems and technologies described above in this application include digital electronic circuit systems, integrated circuit systems, field-programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), application-specific standard products (ASSPs), and system-on-chip systems. Pu SOC) The system , complex These can be implemented in 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, which can be executed and / or interpreted on a programmable system comprising at least one programmable processor, which may be a dedicated or general-purpose programmable processor, which 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, at least one input device, and at least one output device.

[0146] It should be understood that the order, additions, or deletions of the steps can be made using the various forms of processes described above. For example, each step described herein may be performed in parallel, sequentially, or in a different order, as long as the results intended by the technical solution disclosed herein are achieved, and is not limited herein.

[0147] The specific embodiments described above do not constitute a limitation on the scope of protection of this application. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions are possible based on design requirements and other factors. Any modifications, equivalent substitutions, improvements, etc., made within the scope of the principles of this application should be included within the scope of protection.

[0148] [Cross-reference of related applications] This application claims priority to a Chinese patent application filed with the China National Intellectual Property Administration on August 16, 2023, with application number 202311028247.X, and titled "Grounding protection system, method, electronic equipment and storage medium for new energy power plants," the entirety of which is incorporated herein by reference.

Claims

1. A grounding protection system for a new energy power plant, The system includes a grounding transformer neutral point equipment (10), a first current transformer (CT1), a voltage transformer (PT), and a grounding protection device (20), The new energy power plant has multiple lines, which include one busbar (L1), one transmission line (L2), and multiple branch lines (L3), the branch lines (L3) and the transmission line (L2) are each connected to the busbar (L1), the busbar (L1) is provided with the voltage transformer (PT), the transmission line (L2) is provided with the first current transformer (CT1), the voltage transformer (PT) and the first current transformer (CT1) are each connected to the earthing protection device (20), The voltage transformer (PT) is used to detect the voltage of the busbar (L1), and the first current transformer (CT1) is used to detect the current of the transmission line (L2). The plurality of branch lines (L3) include a grounding transformer branch line (L31) equipped with a grounding transformer (T) and a grounding transformer neutral point equipment (10), the grounding transformer neutral point equipment (10) comprising sequentially connected insulating switches (GL), circuit breakers (DL), and resistors (R), the busbar (L1) being connected to the high-voltage side of the grounding transformer (T), and the neutral point of the grounding transformer (T) being sequentially grounded via the insulating switches (GL), circuit breakers (DL), and resistors (R). The earthing protection device (20) is used to collect the voltage of the busbar (L1) and the current of the transmission line (L2), perform amplitude-phase comparison, collect the closed / open state of the circuit breaker (DL), determine whether or not an earthing fault has occurred on the transmission network side to which the transmission line (L2) is connected, obtain a first determination result, generate a corresponding open / close command according to the first determination result, and transmit the open / close command to the circuit breaker (DL). The circuit breaker (DL) performs the corresponding open / close operation in accordance with the open / close command. The earth protection device (20) comprises a processing module (U), and analog quantity input acquisition module (AI), switching quantity input acquisition module (BI), and output module (BO), respectively connected to the processing module (U). The analog quantity input acquisition module (AI) comprises a first interface (AI01) and a tenth interface (AI10), wherein the first interface (AI01) is connected to the first current transformer (CT1), and the tenth interface (AI10) is connected to the voltage transformer (PT). The switching amount input collection module (BI) includes a first interface (BI01) of the switching amount input collection module, the first interface (BI01) of the switching amount input collection module is connected to the circuit breaker (DL), and is used to collect the closed / open state of the circuit breaker (DL). The output module (BO) comprises a fifth interface (BO05) and a sixth interface (BO06), wherein the fifth interface (BO05) is connected to the trip circuit of the circuit breaker (DL) and used to output an open command, and the sixth interface (BO06) is connected to the close circuit of the circuit breaker (DL) and used to output a close command. The processing module (U) comprises a first processing circuit (U1) and a second processing circuit (U2) connected in parallel, and the output module (BO) comprises an output relay (J1) and a start 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) becoming the fifth interface (BO05) of the output module, and the sixth output relay (J16) becoming 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 sequentially, and the second processing circuit (U2) comprises a second analog-to-digital conversion module (23) and a second processor (24) connected sequentially. The first processor (22) is 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), respectively, and the second processor (24) is connected to the start relay (J2), The starting relay (J2) controls whether or not to turn on the positive power supply of the output relay (J1). The plurality of branch lines (L3) further include a current collector line (L32) and an SVG line (L33), the current collector line (L32) is provided with a second current transformer (CT2), the SVG line (L33) is provided with a third current transformer (CT3), and the grounding transformer branch line (L31) is provided with a fourth current transformer (CT4) 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 in the current collection line (L32), the current in the SVG line (L33), and the current in the grounding transformer branch line (L31), respectively. The earthing protection device (20), when the circuit breaker (DL) is open, performs a threshold comparison with the voltage of the busbar (L1), and if the voltage of the busbar (L1) is greater than or equal to a predetermined threshold, performs calculations and amplitude phase comparisons with the voltage of the busbar (L1), the current of the transmission line (L2), the current of the current collector line (L32), the current of the SVG line (L33), and the current of the earthing transformer branch line (L31) to determine whether or not an earthing fault has occurred in the busbar (L1), and obtains a second determination result. The earthing protection device (20), when the circuit breaker (DL) is open, performs a threshold comparison with the voltage of the busbar (L1), and if the voltage of the busbar (L1) is equal to or greater than the predetermined threshold, performs calculations and amplitude-phase comparisons with the voltage of the busbar (L1) and the current of the current collector line (L32) to determine whether or not an earthing fault has occurred in the current collector line (L32), and obtains a third determination result. The earthing protection device (20), when the circuit breaker (DL) is open, performs a threshold comparison with the voltage of the busbar (L1), and if the voltage of the busbar (L1) is equal to or greater than the predetermined threshold, performs calculations and amplitude-phase comparisons with the voltage of the busbar (L1) and the current of the SVG line (L33) to determine whether or not an earthing fault has occurred in the SVG line (L33), and obtains a fourth determination result. The earthing protection device (20) is characterized in that, when the circuit breaker (DL) is in an open state, it performs a threshold comparison with the voltage of the busbar (L1), and if the voltage of the busbar (L1) is equal to or greater than the predetermined threshold, it performs calculations and amplitude-phase comparisons with the voltage of the busbar (L1) and the current of the earthing transformer branch line (L31) to determine whether or not an earthing fault has occurred in the earthing transformer branch line (L31) and to obtain a fifth determination result.

2. The analog quantity input acquisition module (AI) further comprises a second interface (AI02), a third interface (AI03), and a fourth interface (AI04), The second interface (AI02) of the analog quantity input acquisition module is connected to the second current transformer (CT2), The third interface (AI03) of the analog quantity input acquisition module is connected to the third current transformer (CT3), The new energy power plant grounding protection system according to claim 1, characterized in that the fourth interface (AI04) of the analog quantity input acquisition module is connected to the fourth current transformer (CT4).

3. The output module (BO) further comprises a first interface (BO01), a second interface (BO02), a third interface (BO03), and a fourth interface (BO04), wherein the first interface (BO01) is a first output relay (J11), the second interface (BO02) is a second output relay (J12), the third interface (BO03) is a third output relay (J13), and the fourth interface (BO04) is a fourth output relay (J14). In the transmission line (L2), a first circuit breaker (DL1) is further provided, located between the first current transformer (CT1) and the busbar (L1), and the trip circuit of the first circuit breaker (DL1) is connected to the first interface (BO01) of the output module. A second circuit breaker (DL2) is further provided in the current collection line (L32) between the second current transformer (CT2) and the busbar (L1), and the trip circuit of the second circuit breaker (DL2) is connected to the second interface (BO02) of the output module. In the SVG line (L33), a third circuit breaker (DL3) is further provided, located between the third current transformer (CT3) and the busbar (L1), and the trip circuit of the third circuit breaker (DL3) is connected to the third interface (BO03) of the output module. In the grounding transformer branch line (L31), a fourth circuit breaker (DL4) is further provided, located between the fourth current transformer (CT4) and the busbar (L1), and the trip 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 transmit protective trip signals to the first circuit breaker (DL1), the second circuit breaker (DL2), the third circuit breaker (DL3), and the fourth circuit breaker (DL4) via the first interface (BO01), the second interface (BO02), the third interface (BO03), and the fourth module (BO04) of the output module, respectively, when the second determination result indicates that a ground fault has occurred in the busbar (L1). The processing module (U) is further used to transmit a protective trip signal to the second circuit breaker (DL2) via the second interface (BO02) of the output module when the third determination result indicates that a ground fault has occurred in the current collection line (L32). The processing module (U) is further used to transmit a protective trip signal to the third circuit breaker (DL3) via the third interface (BO03) of the output module when the fourth determination result indicates that a ground fault has occurred in the SVG line (L33). The new energy power plant grounding protection system according to claim 1, further characterized in that the processing module (U) is used to transmit a protection trip signal to the fourth circuit breaker (DL4) via the fourth interface (BO04) of the output module when the fifth determination result indicates that a grounding fault has occurred in the grounding transformer branch line (L31).

4. The earthing protection system further comprises a fifth current transformer (CT5) provided between the resistor (R) and the ground, and a temperature control switch (TJ) in the 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 in the resistor (R). The second interface (BI02) of the switching amount input acquisition module is connected to the temperature control switch (TJ) and is used to acquire the state of the temperature control switch (TJ). The new energy power plant earthing protection system according to claim 3, characterized in that the processing module (U) is used to calculate the cumulative heat amount of the resistor (R) according to the current of the resistor (R) when the temperature control switch (TJ) is in the closed state, and to send an open-circuit command to the circuit breaker (DL) via the fifth interface (BO05) of the output module if the cumulative heat amount of the resistor (R) is equal to or greater than a predetermined heat threshold, and to send a protection trip signal to the fourth circuit breaker (DL4) via the fourth interface (BO04) of the output module after a predetermined time delay.

5. The voltage transformer detects the voltage of the busbar and transmits the busbar voltage to the earthing protection device, and the first current transformer detects the current of the transmission line and transmits the current of the transmission line to the earthing protection device. The earth protection device collects the voltage of the busbar and the current of the transmission line, performs amplitude-phase comparison, collects the closed / open state of the circuit breaker, determines whether or not an earth fault has occurred on the transmission network side to which the transmission line is connected, obtains a first determination result, generates a corresponding open / close command according to the first determination result, and transmits the open / close command to the circuit breaker, and A method for protecting the grounding of a new energy power plant, applicable to the grounding protection system of a new energy power plant according to any one of claims 1 to 4, characterized in that the circuit breaker performs a corresponding open / close operation in accordance with the open / close command.

6. Equipped with at least one processor and memory, The aforementioned memory stores computer execution instructions, The electronic device is characterized in that the at least one processor executes computer execution instructions stored in the memory, thereby enabling the at least one processor to perform the ground protection method for a new energy power plant described in claim 5.

7. A computer-readable storage medium, characterized in that it stores computer execution instructions, and when the computer execution instructions are executed by a processor, the ground protection method for a new energy power plant described in claim 5 is implemented.

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