Zero sequence overcurrent protection method for energy storage system energy storage transformer

Abstract

The application discloses a zero sequence overcurrent protection method and system for an energy storage system energy storage transformer, and belongs to the field of relay protection. The method comprises the following steps: collecting zero sequence currents of an energy storage system energy storage transformer; judging whether the zero sequence currents are greater than zero sequence protection setting values; if the zero sequence currents are greater than the zero sequence protection setting values, judging a current no-load closing state of the transformer through a control word to obtain a judgment result; and selecting a zero sequence protection action delay according to the judgment result. The method can set zero sequence protection setting values and zero sequence protection action delays in no-load test processes and non-no-load test processes through the setting of the control word [no-load closing], thereby effectively avoiding the occurrence of false tripping of the energy storage transformer zero sequence overcurrent protection in the no-load closing test process of the transformer.

Description

Technical Field

[0001] This invention relates to the field of relay protection, specifically to a method, system, device, medium, and program for zero-sequence overcurrent protection of an energy storage transformer in an energy storage system. Background Technology

[0002] In power systems, energy storage systems are playing an increasingly important role as a key component in improving energy efficiency and enhancing grid stability and flexibility. With the large-scale integration of renewable energy, its volatility and intermittency pose significant challenges to the stable operation of the power grid. Energy storage systems can effectively store excess electrical energy and release it when needed, playing a role in peak shaving and valley filling, balancing supply and demand, and thus ensuring the safe and reliable operation of the power system.

[0003] Energy storage systems are typically connected to high-voltage power grid systems via energy storage transformers and feeders to achieve energy exchange and efficient management with the grid. As a core component of the energy storage system, the energy storage transformer performs crucial functions such as voltage transformation and electrical isolation; its operating status directly affects the performance and safety of the entire energy storage system. Given the critical role of energy storage transformers in the power system and the potentially severe consequences of their failures, such as equipment damage, partial power outages, and even disruptions to the stable operation of the entire power grid, configuring reliable relay protection devices and setting appropriate relay protection settings is particularly important. Relay protection devices can quickly and accurately operate when a transformer malfunctions or operates abnormally, disconnecting the faulty section, preventing the accident from escalating, protecting other equipment in the power system from damage, and maintaining the normal operation of the system.

[0004] Currently, zero-sequence overcurrent protection is a crucial protective measure against transformer grounding faults in transformer relay protection configurations. It detects the magnitude and changes in zero-sequence current; when the zero-sequence current exceeds a preset value, it determines that a grounding fault has occurred in the transformer and quickly trips to disconnect the faulty transformer, preventing further escalation of the fault. However, existing transformer zero-sequence overcurrent protection configurations have revealed some problems that urgently need to be addressed in practical applications, especially during the operation of energy storage transformers.

[0005] During no-load closing tests of energy storage transformers, the zero-sequence overcurrent protection often trips erroneously. This is because at the instant the transformer is closed under no-load conditions, a large zero-sequence inrush current is generated due to the magnetic saturation characteristics of the iron core. The amplitude of this zero-sequence inrush current may be much larger than the zero-sequence current during normal operation. However, existing zero-sequence overcurrent protection devices are not designed to fully account for the impact of this special case, causing the protection device to mistakenly identify the zero-sequence inrush current as a fault current, thus triggering the protection action and causing the transformer to trip.

[0006] The most direct solution to this malfunction problem is to increase the setting of the zero-sequence overcurrent protection of the energy storage transformer or to lengthen the protection action delay. However, both methods have significant drawbacks. Increasing the protection setting reduces the sensitivity of the zero-sequence overcurrent protection to actual ground faults, potentially causing the protection device to fail to operate in time during minor ground faults, allowing the fault to continue to develop and causing more serious damage to the transformer. While extending the protection action delay can avoid malfunctions caused by zero-sequence inrush current to some extent, it severely affects the speed of the zero-sequence overcurrent protection during non-no-load closing, making it unable to quickly clear the fault and increasing the scope and severity of the fault's harm to the system and equipment. Summary of the Invention

[0007] To address the problem that existing transformer zero-sequence overcurrent protection does not consider the influence of zero-sequence inrush current, leading to false tripping of the zero-sequence overcurrent protection during no-load closing of energy storage transformers, this invention provides a zero-sequence overcurrent protection method for energy storage transformers in energy storage systems. By setting the control word [no-load closing], the zero-sequence protection setting value and zero-sequence protection action delay are set separately during no-load and non-no-load tests, effectively avoiding false tripping of the zero-sequence overcurrent protection of the energy storage transformer during transformer no-load closing tests.

[0008] To achieve the above objectives, the present invention provides the following technical solution.

[0009] In a first aspect, the present invention provides a zero-sequence overcurrent protection method for an energy storage transformer in an energy storage system, comprising: Collect the zero-sequence current of the energy storage transformer in the energy storage system; Determine whether the zero-sequence current is greater than the zero-sequence protection setting value; If the zero-sequence current is greater than the zero-sequence protection setting value, the current no-load closing state of the transformer is determined by the control word, and the judgment result is obtained. Select the zero-sequence protection action delay based on the judgment result.

[0010] As a further improvement of the present invention, the method of collecting the zero-sequence current of the energy storage transformer in the energy storage system includes: The energy storage system's transformer current data is obtained from sensor data acquisition, or... The transformer current data of the energy storage system is obtained by logically superimposing the three-phase current vectors based on the protection device.

[0011] As a further improvement of the present invention, the step of determining whether the zero-sequence current is greater than the zero-sequence protection setting value includes: Real-time calculation of the effective value of zero-sequence current. The effective value of the zero-sequence current is compared with the zero-sequence protection setting value I0.set of the energy storage transformer to determine whether the zero-sequence current is greater than the zero-sequence protection setting value.

[0012] As a further improvement of the present invention, the effective value of the zero-sequence current is compared with the zero-sequence protection setting value I0.set of the energy storage transformer, and then: If the zero-sequence current is less than the zero-sequence protection setting value, the protection device determines that the operating conditions have not been met and does not activate the zero-sequence overcurrent protection logic.

[0013] As a further improvement of the present invention, if the zero-sequence current is greater than the zero-sequence protection setting value, the current no-load closing state of the transformer is determined by the control word to obtain the judgment result; When the protection device detects that the measured zero-sequence current is greater than the setting value I0.set, it reads the status of the control word [no-load closing]. If the control word [no-load closing] is 1, it is determined that the transformer is currently in the no-load closing state; If the control word [no-load closing] is 0, it is determined that the circuit is in a non-no-load closing state.

[0014] As a further improvement of the present invention, the step of selecting the zero-sequence protection action delay based on the judgment result includes: If the control word [no-load closing] is 1, it is determined that the transformer is currently in the no-load closing state, and the first delay t0.set1 is selected; If the control word [no-load closing] is 0, it is determined that the circuit is in a non-no-load closing state, and the second delay t0.set2 is selected; In this case, t0.set1 > t0.set2.

[0015] In a second aspect, the present invention provides a zero-sequence overcurrent protection system for an energy storage transformer in an energy storage system, comprising: Zero-sequence current acquisition module: used to acquire the zero-sequence current of the energy storage transformer in the energy storage system; Zero-sequence current detection module: Used to determine whether the zero-sequence current is greater than the zero-sequence protection setting value; The judgment result acquisition module is used to determine the current no-load closing state of the transformer by using control words if the zero-sequence current is greater than the zero-sequence protection setting value, and obtain the judgment result. Select Action Protection Module: Used to select the zero-sequence protection action delay based on the judgment result.

[0016] Thirdly, the present invention provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the zero-sequence overcurrent protection method for an energy storage transformer in an energy storage system.

[0017] Fourthly, the present invention provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the zero-sequence overcurrent protection method for an energy storage transformer in an energy storage system.

[0018] Fifthly, the present invention provides a computer program product, including computer instructions, which, when executed by a processor, implement the zero-sequence overcurrent protection method for an energy storage transformer in an energy storage system.

[0019] Compared with the prior art, the present invention has the following beneficial effects: This invention collects the zero-sequence current of the energy storage transformer in an energy storage system, providing a solid and accurate data foundation for subsequent judgment and protection actions, ensuring that every decision is based on reliable information. Next, it determines whether the zero-sequence current exceeds the zero-sequence protection setpoint, quickly identifying potential abnormal current situations and gaining valuable time for timely protection measures. When the zero-sequence current exceeds the zero-sequence protection setpoint, the current no-load closing state of the transformer is determined via control words, and a judgment result is obtained. This step considers the characteristic differences of the transformer under different operating conditions, especially the special influence of the zero-sequence inrush current during no-load closing, making the protection strategy more closely aligned with actual conditions. Finally, the zero-sequence protection action delay is selected based on the judgment result, achieving precise and intelligent protection actions. By setting the zero-sequence protection setpoint and zero-sequence protection action delay for the no-load and non-no-load test processes respectively via control words, the protection strategy can be dynamically adjusted according to the actual operating state of the transformer. During the no-load closing test, the protection action delay was reasonably extended, which effectively avoided false tripping caused by zero-sequence inrush current and ensured the smooth progress of the transformer no-load closing test. During the non-no-load test, it can ensure that when a zero-sequence overcurrent fault actually occurs, it can act quickly and accurately, cut off the fault current in time, prevent the fault from expanding, and improve the stability and safety of the energy storage system and the operation of the energy storage transformer. Attached Figure Description

[0020] The accompanying drawings described herein are for illustrative purposes only and are not intended to limit the scope of the invention in any way. In the drawings: Figure 1 This is a flowchart illustrating a zero-sequence overcurrent protection method for an energy storage transformer in an energy storage system according to the present invention. Figure 2 This is a logic diagram of the present invention; Figure 3 This is a schematic diagram of zero-sequence overcurrent protection of the energy storage transformer in an embodiment of the present invention; Figure 4 This is a schematic diagram of the zero-sequence overcurrent protection system of an energy storage transformer in an energy storage system according to the present invention; Figure 5This is a schematic diagram of an electronic device in an embodiment of the present invention. Detailed Implementation

[0021] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. The described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0023] To address the problem that existing transformer zero-sequence overcurrent protection technologies do not consider the influence of zero-sequence inrush current, leading to false tripping of the zero-sequence overcurrent protection when the energy storage transformer is closed under no-load conditions, this invention provides a zero-sequence overcurrent protection method for energy storage transformers in energy storage systems. Figure 1 As shown, it includes: S100: Collects the zero-sequence current of the energy storage transformer in the energy storage system; S200: Determine whether the zero-sequence current is greater than the zero-sequence protection setting value; S300: If the zero-sequence current is greater than the zero-sequence protection setting value, the current no-load closing state of the transformer is determined by the control word, and the judgment result is obtained; S400: Select the zero-sequence protection action delay based on the judgment result.

[0024] This method sets the zero-sequence protection settings and zero-sequence protection action delay during the no-load test and non-no-load test by setting the control word [no-load closing], which effectively avoids the situation where the zero-sequence overcurrent protection of the energy storage transformer trips falsely during the transformer no-load closing test.

[0025] The present invention will be further explained and described below with reference to the accompanying drawings.

[0026] A method for zero-sequence overcurrent protection of an energy storage transformer in an energy storage system includes the following steps: S1: The energy storage system's energy storage transformer protection device collects either the self-generated zero-sequence current or the external zero-sequence current. Specifically, the zero-sequence current is collected by the energy storage transformer protection device of the energy storage system. The zero-sequence current can be obtained by a dedicated sensor (external zero-sequence CT) or by the internal logic superposition calculation of the three-phase current vectors of the protection device (self-generated zero-sequence current).

[0027] If the zero-sequence overcurrent protection device collects a zero-sequence current that is greater than the zero-sequence protection setting value, it will determine whether the transformer is in an no-load closed state through the control word [no-load closing]. After the set zero-sequence protection action delay, it will trip or send a signal through the output of the control word [zero-sequence overcurrent protection trip / signal]. When the energy storage transformer in an energy storage system is closed under no-load conditions, a large inrush current is generated instantaneously due to the instantaneous increase in voltage and the nonlinear core saturation. Furthermore, because the closing angle, residual magnetism, and core characteristics of the transformer differ during no-load closure, the inrush current in the zero-sequence path is asymmetrical, resulting in zero-sequence inrush current, which can cause malfunctions of the zero-sequence protection.

[0028] The magnitude of the inrush current when the energy storage transformer of an energy storage system is closed under no-load conditions is closely related to the system voltage, closing angle, system operating mode, core residual magnetism, and transformer parameters.

[0029] When the energy storage transformer of the energy storage system is closed under no-load and an inrush current occurs, the zero-sequence current resulting from the superposition of the three-phase inrush currents is no longer zero due to the different closing angles, residual magnetism and core characteristics of phases A, B and C. Generally, zero-sequence overcurrent protection does not have inrush current blocking function. When the amplitude of the zero-sequence inrush current is large and reaches the zero-sequence protection setting value, the zero-sequence protection will malfunction, affecting the normal no-load closing test of the transformer.

[0030] S2: During the no-load test of the energy storage transformer, if Figure 2 As shown, the corresponding control word [no-load closing] in the protection device is set to 1, and the zero-sequence protection setting value of the energy storage transformer is set to I0.set, with a delay of t0.set1. The setting value I0.set must meet the calculation guidelines for zero-sequence protection settings of low-voltage plant service transformers, and should meet the requirements of zero-sequence protection sensitivity, selectivity, and speed. The setting of t0.set1 must be set according to avoid the decay time of the inrush current during the transformer no-load test, and the speed of protection must also be considered.

[0031] The control word [no-load closing] is set to 1 or 0, where 1 represents "the energy storage transformer of the energy storage system is in no-load closing operation state" and 0 represents "the energy storage transformer of the energy storage system is in non-no-load closing operation state". It can be set in the protection device through the relay protection setting sheet.

[0032] When the control word [no-load closing] is 1, the set zero-sequence protection action delay is t0.set1. When the control word [no-load closing] is 0, the set zero-sequence protection action delay is t0.set2. Considering the influence of zero-sequence inrush current, the set value t0.set1>t0.set2 can effectively avoid the excitation inrush current when the energy storage transformer of the energy storage system is closed under no-load conditions. At the same time, it can also enable the zero-sequence overcurrent protection of the energy storage transformer to quickly and sensitively trip or send signals when the transformer is closed under non-no-load conditions and a ground fault occurs.

[0033] The control word [zero-sequence overcurrent protection trip / signal] can be set to 1 or 0, which correspond to the protection output action of tripping or signaling, respectively, and can be set according to actual needs.

[0034] S3: During the no-load test, when a ground fault occurs inside the transformer or at the transformer terminal, the zero-sequence protection setting reliably avoids the zero-sequence inrush current and correctly trips or alarms; if no fault occurs, the zero-sequence protection setting reliably does not erroneously.

[0035] S4: After the no-load test of the energy storage transformer is completed, the transformer is put into normal operation. Set the corresponding control word [no-load closing] in the protection device to 0, and set the zero-sequence protection setting value of the energy storage transformer to I0.set, with a delay of t0.set2. The setting value I0.set must meet the calculation guidelines for the zero-sequence protection setting of low-voltage plant service transformers, and should meet the requirements of zero-sequence protection sensitivity, selectivity, and speed. The setting of t0.set1 no longer needs to avoid the setting of the inrush current decay time during the no-load test of the transformer. It only needs to consider the speed and selectivity of the protection, that is, to coordinate with the upper and lower level protections of the branch where the transformer is located.

[0036] When the [No-load Closing] control word is set to 1 or 0, the zero-sequence current setting value is I0.set. Under both operating modes, there is no need to change the zero-sequence current setting value. The setting of I0.set must meet the calculation guidelines for zero-sequence protection settings of low-voltage plant service transformers, and should satisfy the requirements for zero-sequence protection sensitivity, selectivity, and speed. When the [No-load Closing] control word is set to 1 or 0, the zero-sequence protection action delay setting value should satisfy t0.set1 > t0.set2, thereby effectively avoiding the influence of zero-sequence inrush current on zero-sequence protection during the no-load closing test.

[0037] S5: During the actual operation of the transformer, when a grounding fault occurs inside the transformer or at the transformer terminal line, the zero-sequence protection setting will quickly and sensitively trip or alarm.

[0038] The zero-sequence protection setting value of the energy storage system is set according to the setting principle of the corresponding low-voltage plant transformer in the regulation "DLT 1502-2016 Plant Power Relay Protection Setting Calculation Guide".

[0039] In summary, this invention adds a [no-load closing] control word to the original logic of the zero-sequence protection of the energy storage transformer in an energy storage system. Furthermore, different zero-sequence protection action delays are set when the [no-load closing] control word is set to 1 and 0, respectively. This improves the situation where the zero-sequence protection of the energy storage transformer malfunctions due to zero-sequence inrush current during no-load closing tests, effectively improving the reliability of the zero-sequence protection action and enhancing the operational safety of the energy storage transformer. Secondly, this invention is simple in principle and easy to implement. While improving the reliability of the zero-sequence protection of the energy storage transformer, it also provides setting methods for relay protection setting personnel.

[0040] The present invention will be further explained and illustrated below with reference to specific embodiments.

[0041] Example like Figure 3 As shown, taking the zero-sequence overcurrent protection of an energy storage transformer in an energy storage system as an example, the implementation process of this invention is explained: 1) The zero-sequence protection setting value I0.set of the transformer is obtained by setting the zero-sequence protection setting value according to the principles of ensuring the sensitivity of the zero-sequence overcurrent protection of the energy storage system, coordinating with the upper and lower levels, and avoiding the maximum unbalanced current.

[0042] 2) Delay setting for zero-sequence overcurrent protection of energy storage transformer: set the delay during no-load closing process to t0.set1=0.1s, and set the delay during non-no-load closing process to t0.set2=0.0s.

[0043] 3) During the no-load test of the energy storage transformer, set the set values ​​to I0.set and t0.set1 respectively, and set the control word [no-load closing] to 1 to ensure that the zero-sequence overcurrent protection does not trip during the no-load test.

[0044] 4) After the no-load test of the energy storage transformer is completed, the transformer is put into operation. Set the set values ​​to I0.set and t0.set2 respectively, and set the control word [no-load closing] to 0.

[0045] This embodiment only lists the setting methods and implementation methods corresponding to the zero-sequence overcurrent protection of energy storage meeting the requirements of the regulations. The final implementation of this invention requires comprehensive setting calculation based on the relay protection settings of the entire power plant.

[0046] The second objective of this invention is to provide a zero-sequence overcurrent protection system for an energy storage transformer in an energy storage system, such as... Figure 4 As shown, it includes: Zero-sequence current acquisition module 101: used to acquire the zero-sequence current of the energy storage transformer in the energy storage system; Zero-sequence current detection module 201: Used to determine whether the zero-sequence current is greater than the zero-sequence protection setting value; The judgment result acquisition module 301 is used to determine the current no-load closing state of the transformer by means of the control word if the zero-sequence current is greater than the zero-sequence protection setting value, and obtain the judgment result. Select Action Protection Module 401: Used to select the zero-sequence protection action delay based on the judgment result.

[0047] like Figure 5 As shown, a third objective of this invention is to provide an electronic device comprising a processor 501, a memory 502, and a display screen 503. The memory 502 and the display screen 503 are both connected to the processor 501, such as via a bus 504. Optionally, the electronic device may further include a transceiver 505. It should be noted that in practical applications, the transceiver 505 is not limited to one type, and the structure of this electronic device does not constitute a limitation on the embodiments of this application.

[0048] Processor 501 may be a CPU (Central Processing Unit), a general-purpose processor, a DSP (Digital Signal Processor), an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. It can implement or execute the various exemplary logic blocks, modules, and circuits described in conjunction with the disclosure of this application. Processor 501 may also be a combination that implements computational functions, such as including one or more microprocessor combinations, a combination of a DSP and a microprocessor, etc.

[0049] Bus 504 may include a pathway for transmitting information between the aforementioned components. Bus 504 may be a PCI (Peripheral Component Interconnect) bus or an EISA (Extended Industry Standard Architecture) bus, etc. Bus 504 can be divided into address bus, data bus, control bus, etc.

[0050] The memory 502 may be a ROM (Read Only Memory) or other type of static storage device capable of storing static information and instructions, RAM (Random Access Memory) or other type of dynamic storage device capable of storing information and instructions, or an EEPROM (Electrically Erasable Programmable Read Only Memory), CD-ROM (Compact Disc Read Only Memory) or other optical disc storage, optical disc storage (including compressed optical discs, laser discs, optical discs, digital universal optical discs, Blu-ray discs, etc.), magnetic disk storage media or other magnetic storage devices, or any other medium capable of carrying or storing desired program code in the form of instructions or data structures and accessible by a computer, but not limited thereto.

[0051] The memory 502 is used to store application code that executes the solution of this application, and its execution is controlled by the processor 501. The processor 501 is used to execute the application code stored in the memory 502 to implement the content shown in the foregoing method embodiments.

[0052] Figure 5 The electronic device shown is merely an example and should not impose any limitation on the functionality and scope of use of the embodiments of this application.

[0053] A fourth objective of this invention is to provide a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, performs the aforementioned functions. Figure 1 The illustrated method embodiments include various processes. For example, a memory may include instructions that can be executed by a processor of an electronic device to perform the described method.

[0054] A computer-readable storage medium can be a tangible device that holds and stores instructions used by an instruction execution device. A computer-readable storage medium can be, but is not limited to, an electrical storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any combination thereof. Specifically, a computer-readable storage medium can be a portable computer disk, a hard disk, a USB flash drive, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), staging random access memory (SRAM), portable compact disc read-only memory (CD-ROM), digital multifunction disc (DVD), memory stick, floppy disk, optical disk, magnetic disk, mechanical encoding device, or any combination thereof.

[0055] A fifth objective of this invention is to provide a computer program product, including computer instructions that, when executed by a processor, implement the above-described... Figure 1 The various processes of the method embodiments shown can achieve the same technical effect, and will not be described again here to avoid repetition.

[0056] Many embodiments and applications beyond the examples provided will be apparent to those skilled in the art upon reading the foregoing description. Therefore, the scope of this teaching should not be determined by reference to the foregoing description, but rather by reference to the foregoing claims and the full scope of their equivalents. For purposes of completeness, all articles and references, including patent applications and publications, are incorporated herein by reference. The omission of any aspect of the subject matter disclosed herein in the foregoing claims is not intended as a waiver of that subject matter, nor should it be construed as an indication that the applicant has not considered that subject matter as part of the disclosed inventive subject matter.

[0057] The above content provides a further detailed description of the present invention. It should not be construed that the specific embodiments of the present invention are limited to this. For those skilled in the art, several simple deductions or substitutions can be made without departing from the concept of the present invention, and all such deductions or substitutions should be considered to fall within the scope of protection of the present invention as defined by the submitted claims.

Claims

1. A method for zero-sequence overcurrent protection of an energy storage transformer in an energy storage system, characterized in that, include: Collect the zero-sequence current of the energy storage transformer in the energy storage system; Determine whether the zero-sequence current is greater than the zero-sequence protection setting value; If the zero-sequence current is greater than the zero-sequence protection setting value, the current no-load closing state of the transformer is determined by the control word, and the judgment result is obtained. Select the zero-sequence protection action delay based on the judgment result.

2. The zero-sequence overcurrent protection method for an energy storage transformer in an energy storage system according to claim 1, characterized in that, The zero-sequence current of the energy storage transformer in the energy storage system is collected, including: The energy storage system's transformer current data is obtained from sensor data acquisition, or... The transformer current data of the energy storage system is obtained by logically superimposing the three-phase current vectors based on the protection device.

3. The zero-sequence overcurrent protection method for an energy storage transformer in an energy storage system according to claim 1, characterized in that, The determination of whether the zero-sequence current is greater than the zero-sequence protection setting value includes: Real-time calculation of the effective value of zero-sequence current. The effective value of the zero-sequence current is compared with the zero-sequence protection setting value I0.set of the energy storage transformer to determine whether the zero-sequence current is greater than the zero-sequence protection setting value.

4. The zero-sequence overcurrent protection method for an energy storage transformer in an energy storage system according to claim 3, characterized in that, The effective value of the zero-sequence current is compared with the zero-sequence protection setting I0.set of the energy storage transformer. Then: If the zero-sequence current is less than the zero-sequence protection setting value, the protection device determines that the operating conditions have not been met and does not activate the zero-sequence overcurrent protection logic.

5. The zero-sequence overcurrent protection method for an energy storage transformer in an energy storage system according to claim 1, characterized in that, If the zero-sequence current is greater than the zero-sequence protection setting value, the current no-load closing state of the transformer is determined by the control word, and the determination result is obtained. When the protection device detects that the measured zero-sequence current is greater than the setting value I0.set, it reads the status of the control word [no-load closing]. If the control word [no-load closing] is 1, it is determined that the transformer is currently in the no-load closing state; If the control word [no-load closing] is 0, it is determined that the circuit is in a non-no-load closing state.

6. The zero-sequence overcurrent protection method for an energy storage transformer in an energy storage system according to claim 5, characterized in that, The step of selecting the zero-sequence protection action delay based on the judgment result includes: If the control word [no-load closing] is 1, it is determined that the transformer is currently in the no-load closing state, and the first delay t0.set1 is selected; If the control word [no-load closing] is 0, it is determined that the circuit is in a non-no-load closing state, and the second delay t0.set2 is selected; In this case, t0.set1 > t0.set2.

7. A zero-sequence overcurrent protection system for an energy storage transformer in an energy storage system, characterized in that, include: Zero-sequence current acquisition module: used to acquire the zero-sequence current of the energy storage transformer in the energy storage system; Zero-sequence current detection module: Used to determine whether the zero-sequence current is greater than the zero-sequence protection setting value; The judgment result acquisition module is used to determine the current no-load closing state of the transformer by using control words if the zero-sequence current is greater than the zero-sequence protection setting value, and obtain the judgment result. Select Action Protection Module: Used to select the zero-sequence protection action delay based on the judgment result.

8. An electronic device, characterized in that, The device includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the zero-sequence overcurrent protection method for an energy storage transformer in an energy storage system as described in any one of claims 1-6.

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program, which, when executed by a processor, implements the zero-sequence overcurrent protection method for an energy storage transformer in an energy storage system as described in any one of claims 1-6.

10. A computer program product, characterized in that, It includes computer instructions that, when executed by a processor, implement a zero-sequence overcurrent protection method for an energy storage transformer in an energy storage system as described in any one of claims 1-6.

Images