220kV line differential protection channel hot switching non-transaction simulation test method and system

Abstract

The invention discloses a 220kV line differential protection channel hot switching non-transaction simulation test method and system. The method comprises the steps that two 220kV line differential protection devices and three OXC devices are networked for operation; respectively outputting three phases of the six-phase balance load current to the 220kV line differential protection devices at two sides to carry out a crossing load simulation test; enabling the C-phase current of the 220kV line differential protection device at one side to drop by 0.3 A, and enabling the 220kV line differential protection devices to start wave recording and carry out optical fiber channel switching; acquiring a protection waveform during switching of the optical fiber channel, judging the state of the 220kV line differential protection device in the switching process of the optical fiber channel, and further judging that there is no transaction in the hot switching process of the secondary 220kV line differential protection channel; and performing a traversing load simulation test in different load states, and judging whether the test passes or not. The invention provides a safety test method suitable for various types of 220kV line protection differential channel hot switching technology, and the safety application of the differential protection hot switching function of the 220kV line which is actually put into operation is ensured.

Description

Technical Field

[0001] The present invention belongs to the technical field of power grid relay protection simulation test, and more specifically, relates to a 220kV line differential protection channel hot switching non-abnormal simulation test method and system. Background Art

[0002] Abnormalities in the protection fiber channel, especially for some single-channel protection, will directly affect its protection function and bring greater safety risks to the operation of the power grid. A method that can quickly restore channel abnormalities is needed. For example, there are still many single-channel situations in the 220kV line dedicated fiber protection. Once interrupted, if it cannot be quickly restored, it will bring greater risks to the operation of the power grid.

[0003] Fault location and exception handling for protecting optical fiber channels are mainly done manually, which is easily restricted by factors such as geographical environment, traffic conditions, and climatic conditions, resulting in heavy workload and low efficiency.

[0004] Differential protection has high requirements for information transmission channels, and needs to ensure channel reliability, channel security, channel attenuation and channel delay. Currently, there is a lack of relatively complete differential protection channel hot switching technology and safety testing and verification methods.

[0005] The existing line differential protection simulation technology is still blank for the safety test of the switching process of the channel hot switching system, and because the line differential protection startup recording principle is usually based on transient mutations, after the line differential protection is interrupted in the channel, the channel hot switching process is only the sudden disappearance of the steady-state current. The existing principle of the protection device only sets alarms, communication interruptions, differential function locks, etc. The line protection cannot start recording and record the changes in transient information such as sampling, differential current, alarms, and locks during the switching process. Therefore, it is extremely important to study and innovatively design a 220kV line protection channel hot switching process protection device to automatically record the transient switching process method and system, and use the system to obtain transient waveform analysis to test the safety of the differential protection channel hot switching technology. Summary of the invention

[0006] In order to solve the deficiencies in the prior art, the present invention provides a 220kV line differential protection channel hot switching non-abnormal simulation test method, which solves the technical problem of low simulation test efficiency in the prior art.

[0007] The present invention adopts the following technical solution.

[0008] A 220kV line differential protection channel hot switching no abnormal simulation test method, comprising the following steps:

[0009] Network two 220kV line differential protection devices and three OXC devices for operation;

[0010] The three phases of the six-phase balanced load current are respectively output to the 220kV line differential protection devices on both sides, and the through load simulation test is performed on the 220kV line differential protection devices:

[0011] The C-phase current of the unilateral 220kV line differential protection device is made to drop by 0.3A, so that the 220kV line differential protection device starts recording waveforms;

[0012] When the 220kV line differential protection device starts recording, the optical fiber channel of the 220kV line differential protection device is switched;

[0013] Obtain the protection waveform during the optical fiber channel switching and determine the status of the 220kV line differential protection device during the optical fiber channel switching process;

[0014] By recording the waveform, the switching process of the differential protection channel is judged, and whether the differential protection is correctly locked and alarmed;

[0015] If the differential protection is correctly locked and alarms during the channel switching process, it is judged that there is no abnormality in the hot switching process of the 220kV line differential protection channel;

[0016] Conduct through-load simulation tests on the 220kV line differential protection device under different load conditions to determine whether the channel switching process of the 220kV line differential protection device under each load condition is normal;

[0017] If there is no abnormality in the hot switching process of the 220kV line differential protection channel under all load conditions, the test is judged to have passed, otherwise the test has failed.

[0018] Preferably, the networking operation of two 220kV line differential protection devices and three OXC devices specifically includes:

[0019] Three OXC devices are networked to form an OXC matrix, and two identical 220kV line differential protection devices are connected to the OXC matrix. Each 220kV line differential protection device is connected to one OXC device. The network management configuration works on the primary path by default. When the primary path fails, it switches to the backup channel through the preset backup route.

[0020] Preferably, the output of six-phase balanced load current to two 220kV line protection units specifically includes:

[0021] Use the relay protection tester to output six-phase balanced load current, among which three-phase currents are equal in magnitude and opposite in direction to the other three-phase currents;

[0022] The relay tester outputs positive-sequence load currents of equal magnitude for the three phases A, B, and C to one 220kV line differential protection device, and outputs the other three-phase load currents of equal magnitude and opposite direction to another 220kV line differential protection device. At the same time, observe that the differential current in the two 220kV line differential protection devices is 0. If the differential current is not 0, check the wiring of the relay tester and correct it until the differential current in the two 220kV line differential protection devices is 0.

[0023] Preferably, the step of causing the C-phase current of the single-side 220kV line differential protection device to drop by 0.3A so that the 220kV line differential protection device starts recording the waveform specifically includes:

[0024] The C-phase current input to one of the 220kV line differential protection devices was reduced by 0.3A through the relay protection tester. At this time, the 220kV line differential protection device started recording due to the sudden change in current.

[0025] Preferably, when the 220kV line protection device is started, switching the optical fiber channel of the 220kV line differential protection device specifically includes:

[0026] The OXC simulation program automatically switches the program to trigger the switch or manually triggers the optical fiber to automatically switch.

[0027] Preferably, capturing the protection waveform during the optical fiber channel switching and determining the state of the protection during the channel switching process specifically includes:

[0028] The waveform recorded when the channel is switched in the 220kV line differential protection device is exported, and the sudden change of differential current of the differential protection at the time of channel switching is observed, and whether the differential protection is locked and alarmed is observed.

[0029] Preferably, if the channel switching process, the differential protection is correctly locked and alarms, specifically includes:

[0030] When confirming the moment of differential protection channel switching, if the differential protection function locking switch quantity and channel alarm switch quantity can be correctly realized, it is judged that there is no abnormality in the hot switching process of the 220kV line differential protection channel.

[0031] Preferably, the simulating switching function under different load states specifically includes:

[0032] Carry out through load simulation test on 220kV line differential protection device when the load state is 0.5A, 1A, 3A, 5A, 10A, 15A, 18A, 20A respectively, and judge whether the channel switching process of 220kV line differential protection device is normal under each load state;

[0033] If there is no abnormality in the hot switching process of the 220kV line differential protection channel under all load conditions, it is judged that the hot switching process of the 220kV line differential protection device channel is safe and reliable.

[0034] The present invention also proposes a 220kV line differential protection channel hot switching no abnormality simulation test system, which is used to implement the 220kV line differential protection channel hot switching no abnormality simulation test method, including: a networking module, a current output module, a test module, and a judgment module;

[0035] The networking module is used to network two 220kV line differential protection devices and three OXC devices;

[0036] The current output module is used to output the three phases of the six-phase balanced load current to the 220kV line differential protection devices on both sides;

[0037] The test module is used to perform a through load simulation test on the 220kV line differential protection device, including: making the C-phase current of the single-side 220kV line differential protection device drop by 0.3A, so that the 220kV line differential protection device starts recording; when the 220kV line differential protection device starts recording, the optical fiber channel of the 220kV line differential protection device is switched; the protection waveform when the optical fiber channel is switched is obtained, and the state of the 220kV line differential protection device during the optical fiber channel switching process is judged; the differential protection channel switching process is judged by the recording waveform, and whether the differential protection is correctly locked and alarmed; simulating the switching function under nine load conditions and performing through load simulation tests under different load conditions;

[0038] The judgment module is used to judge whether the hot switching process of the 220kV line differential protection channel is abnormal: if the differential protection is correctly locked and alarmed during the channel switching process, it is judged that there is no abnormality in the hot switching process of the 220kV line differential protection channel; and to judge whether the 220kV line differential protection device has passed the test: if there is no abnormality in the hot switching process of the 220kV line differential protection channel under all load conditions, it is judged that the test has passed, otherwise the test has failed.

[0039] The present invention also provides a terminal, comprising a processor and a storage medium;

[0040] The storage medium is used to store instructions;

[0041] The processor is used to operate according to the instructions to execute the steps of the 220kV line differential protection channel hot switching without abnormal movement simulation test method.

[0042] The present invention also proposes a computer-readable storage medium on which a computer program is stored. When the program is executed by a processor, the steps of the 220kV line differential protection channel hot switching without abnormal movement simulation test method are implemented.

[0043] The beneficial effect of the present invention is that, compared with the prior art, the 220kV line differential protection channel hot switching simulation test method proposed in the present invention can fully simulate the on-site 220kV line protection channel hot switching architecture, tester simulation of through load current, slight mutation start recording, fault waveform diagnosis correct locking, and realize correct testing of the differential protection locking correctness during hot switching of various load channels in a laboratory simulation environment, thereby ensuring the safety of large-scale actual operation in the later stage.

[0044] The 220kV line differential protection channel hot switching safety assurance test technology constructed by the present invention can simulate different load conditions and the channel automatic switching process by bridging the simulation environment in the laboratory, and realize transient recording of the whole process of channel hot switching during the test by selecting the optimal current drop value. Combined with the automatic transient fault recording of the protection device, the differential protection differential current mutation, locking state, alarm function and other data are analyzed in detail. Through simulation, the channel hot switching function of the actual operation in the later stage is ensured to be normal, so as to further enhance the self-healing and reliability of the 220kV line differential protection function and ensure the safety of the large power grid.

[0045] The present invention can help the relay protection operation and maintenance personnel of the power grid company to realize transient recording of the whole process of channel hot switching by building a simulation platform in the laboratory link before the relevant products of 220kV line protection channel hot switching are actually put into operation, and use the simulation method and system of the dual-state starting quantity mutation flipping state of the relay protection tester with different load levels to provide ms-level quantitative curves of the whole process sampling mutation quantity, differential current mutation quantity, device locking switch quantity, and device alarm switch quantity. Compared with the traditional balanced load channel hot switching that cannot record the whole process transiently and judge the internal switch quantity of the device, the simulation method and system can test the safety of various products in the transient process of channel hot switching, can identify various potential unsafe products, and significantly enhance the safety of the application of the 220kV line protection channel hot switching function. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 It is a flow chart of the simulation test method for hot switching of 220kV line differential protection channel without abnormal movement in the present invention;

[0047] Figure 2 It is a schematic diagram of the networking operation of two 220kV line protection devices of the same model and version and three OXC devices in the present invention;

[0048] Figure 3It is a structural diagram of the 220kV line differential protection channel hot switching without abnormal movement simulation test system in the present invention. DETAILED DESCRIPTION

[0049] In order to make the purpose, technical scheme and advantages of the present invention clearer, the technical scheme of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. The embodiments described in this application are only part of the embodiments of the present invention, not all of them. Based on the spirit of the present invention, other embodiments obtained by ordinary technicians in this field without creative work are all within the scope of protection of the present invention.

[0050] like Figure 1 As shown, the present invention provides a simulation test method for hot switching of 220kV line differential protection channels without abnormal changes. By bridging the simulation environment in the laboratory, simulating different load conditions and the automatic switching process of the channels, combining the automatic transient fault recording of the protection device, and refining and analyzing the data such as the differential current mutation, the locking state, and the alarm function of the differential protection, the simulation is used to ensure that the hot switching function of the actual channel put into operation later is normal, including the following contents:

[0051] Network two 220kV line differential protection devices and three OXC devices for operation;

[0052] like Figure 2 As shown, two 220kV line differential protection devices of the same model and version and three OXC devices are networked and operated, which means that three OXC devices are networked, and two relay protection devices are connected to the OXC matrix. The network management configuration works on the main path by default. When the main path fails, it switches to the backup channel through the preset backup route.

[0053] Among them, the main path refers to the point-to-point direct connection path between two 220kV line differential protection devices and the OXC equipment.

[0054] Furthermore, three phases of the six-phase balanced load current are respectively output to the 220kV line differential protection devices on both sides, and a through load simulation test is performed on the 220kV line differential protection devices;

[0055] The C-phase current of the unilateral 220kV line differential protection device is made to drop by 0.3A, so that the 220kV line differential protection device starts recording waveforms;

[0056] When the 220kV line differential protection device starts recording, the optical fiber channel of the 220kV line differential protection device is switched;

[0057] Obtain the protection waveform during the optical fiber channel switching and determine the status of the 220kV line differential protection device during the optical fiber channel switching process;

[0058] By recording the waveform, the switching process of the differential protection channel is judged, and whether the differential protection is correctly locked and alarmed;

[0059] If the differential protection is correctly locked and alarms during the channel switching process, it is judged that there is no abnormality in the hot switching process of the 220kV line differential protection channel;

[0060] Among them, the output of six-phase balanced load current to two 220kV line protection units includes:

[0061] Use the relay protection tester to output six-phase balanced load current, among which three-phase currents are equal in magnitude and opposite in direction to the other three-phase currents;

[0062] The relay tester outputs positive-sequence load currents of equal magnitude for the three phases A, B, and C to one 220kV line differential protection device, and outputs the other three-phase load currents of equal magnitude and opposite direction to another 220kV line differential protection device. At the same time, observe that the differential current in the two 220kV line differential protection devices is 0. If the differential current is not 0, check the wiring of the relay tester and correct it until the differential current in the two 220kV line differential protection devices is 0.

[0063] The C-phase current of the single-side load current drops by 0.3A, so that the protection device starts recording the waveform, which includes:

[0064] The C-phase current input to one of the 220kV line differential protection devices is reduced by 0.3A through the relay protection tester. At this time, the 220kV line differential protection device starts recording due to the sudden change of current. Specifically, in the present invention, it is preferred to reduce the C-phase current by 0.3A to realize transient recording of the whole process of channel hot switching:

[0065] In the first phase of the test, an attempt was made to directly unplug the dual-core or single-core on one side to simulate the communication interruption state before channel switching. After four physical communication interruption tests on both sides, the line protection always only triggered the channel alarm and locked the differential protection. It was impossible to start and transiently record the waveform. The test analysis showed that there was no sudden change in the sampling value on the side of the communication interruption. The alarm was only triggered by the sudden loss of the sampling value on the opposite side. The differential current value could not be used as the starting quantity to trigger the transient recording.

[0066] In the second phase of the test, the protective device was observed to start the set value of 0.2A on one side of the change amount. In order to ensure that the line protection can reliably start recording at the moment of channel hot switching, two states were set through the relay protection tester. One state was a three-phase through balanced load. The second state was triggered synchronously at the moment of channel hot switching and only the single-side C phase was reduced by 0.3A. The protective device successfully realized the transient recording of the whole process of channel hot switching; when the C phase was reduced by 0.1A, the protective device could not realize the transient recording of the whole process of channel hot switching; when the C phase was reduced by 0.15A, the protective device could not realize the transient recording of the whole process of channel hot switching; when the C phase was reduced by 0.25A, the protective device successfully realized the transient recording of the whole process of channel hot switching. The experiment shows that at the moment of channel hot switching, the value of the single-side current mutation must be greater than the start set value of 0.2A to start recording.

[0067] In the third phase of the test, the second phase test was carried out simultaneously on phases A and B. The test obtained the same results, further verifying that in order to achieve transient recording of the entire process of channel hot switching, the single-side sampling value mutation must be set to be greater than the starting fixed value sampling amount, which can realize transient recording of the entire process of line protection channel hot switching.

[0068] When the 220kV line protection device is started, the optical fiber channel of the 220kV line differential protection device is switched, specifically including:

[0069] When the protection is started, the differential protection fiber channel is switched manually or automatically. There are two ways: the OXC simulation program automatically switches the program to trigger the switching, or the fiber is manually triggered to automatically switch.

[0070] The protection waveform during the optical fiber channel switching is captured to determine the protection status during the channel switching process, specifically including:

[0071] The protection waveform of the optical fiber channel switching is captured to determine the status of the protection during the channel switching process. This is done by deriving the waveform recorded at the time of channel switching in the 220kV line differential protection device, and observing the sudden change of differential current in the 220kV line differential protection device at the time of channel switching, and whether the differential protection is locked and alarmed.

[0072] If the differential protection is correctly locked and alarmed during the channel switching process, it means that at the moment of confirming the switching of the differential protection channel, the differential current maintains the sampling value of one side (differential protection differential current mutation diagnosis), and after the differential current amplitude suddenly changes, the differential protection function locking switch quantity (locking state diagnosis) and the channel alarm switch quantity (alarm function diagnosis) of the whole process are realized at the same time, then it is judged that there is no abnormality in the hot switching process of the 220kV line differential protection channel. Otherwise, it is judged that there is an abnormality in the hot switching process of the 220kV line differential protection channel, and the test fails.

[0073] Furthermore, the switching function under different load conditions is simulated and the above-mentioned through-load simulation test is repeated. The load conditions are 0.5A, 1A, 3A, 5A, 10A, 15A, 18A, and 20A respectively. When it is confirmed that the channel switching process is all reliably and correctly locked, the 220kV line differential protection channel hot switching process is judged to be safe and reliable, and the test passes, otherwise the test fails.

[0074] like Figure 3 As shown, the present invention also proposes a 220kV line differential protection channel hot switching without abnormal simulation test system, which is used to implement the above-mentioned 220kV line differential protection channel hot switching without abnormal simulation test method, the system includes: a networking module, a current output module, a test module, and a judgment module;

[0075] Among them, the networking module is used to network and operate two 220kV line differential protection devices and three OXC devices;

[0076] The current output module is used to output the three phases of the six-phase balanced load current to the 220kV line differential protection devices on both sides;

[0077] The test module is used to perform a through load simulation test on the 220kV line differential protection device, including: making the C-phase current of the single-side 220kV line differential protection device drop by 0.3A, so that the 220kV line differential protection device starts recording; when the 220kV line differential protection device starts recording, the optical fiber channel of the 220kV line differential protection device is switched; the protection waveform when the optical fiber channel is switched is obtained, and the state of the 220kV line differential protection device during the optical fiber channel switching process is judged; the differential protection channel switching process is judged by the recording waveform, and whether the differential protection is correctly locked and alarmed; simulating the switching function under nine load conditions and performing through load simulation tests under different load conditions;

[0078] The judgment module is used to judge whether the hot switching process of the 220kV line differential protection channel is abnormal: if the differential protection is correctly locked and alarmed during the channel switching process, it is judged that there is no abnormality in the hot switching process of the 220kV line differential protection channel; and to judge whether the 220kV line differential protection device has passed the test: if there is no abnormality in the hot switching process of the 220kV line differential protection channel under all load conditions, it is judged that the test has passed, otherwise the test has failed.

[0079] The beneficial effect of the present invention is that, compared with the prior art, the present invention proposes a safety test method for hot switching technology of differential channels of protection of various types of 220kV lines, thereby ensuring the safe application of hot switching function of differential protection of 220kV lines in actual operation.

[0080] The present disclosure may be a system, a method and / or a computer program product. The computer program product may include a computer-readable storage medium carrying computer-readable program instructions for causing a processor to implement various aspects of the present disclosure.

[0081] A computer-readable storage medium may be a tangible device that can hold and store instructions used by an instruction execution device. A computer-readable storage medium may be, for example, but not limited to, an electrical storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the foregoing. More specific examples of computer-readable storage media (a non-exhaustive list) include: a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), a static random access memory (SRAM), a portable compact disk read-only memory (CD-ROM), a digital versatile disk (DVD), a memory stick, a floppy disk, a mechanical encoding device, such as a punch card or a raised structure in a groove on which instructions are stored, and any suitable combination of the foregoing. As used herein, a computer-readable storage medium is not to be interpreted as a transient signal per se, such as a radio wave or other freely propagating electromagnetic wave, an electromagnetic wave propagating through a waveguide or other transmission medium (e.g., a light pulse through a fiber optic cable), or an electrical signal transmitted through a wire.

[0082] The computer-readable program instructions described herein can be downloaded from a computer-readable storage medium to each computing / processing device, or downloaded to an external computer or external storage device via a network, such as the Internet, a local area network, a wide area network, and / or a wireless network. The network can include copper transmission cables, optical fiber transmissions, wireless transmissions, routers, firewalls, switches, gateway computers, and / or edge servers. The network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and forwards the computer-readable program instructions for storage in the computer-readable storage medium in each computing / processing device.

[0083] The computer program instructions for performing the operation of the present disclosure may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-related instructions, microcode, firmware instructions, state setting data, or source code or object code written in any combination of one or more programming languages, including object-oriented programming languages, such as Smalltalk, C++, etc., and conventional procedural programming languages, such as "C" language or similar programming languages. Computer-readable program instructions may be executed completely on a user's computer, partially on a user's computer, as an independent software package, partially on a user's computer, partially on a remote computer, or completely on a remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer via any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., using an Internet service provider to connect via the Internet). In some embodiments, an electronic circuit, such as a programmable logic circuit, a field programmable gate array (FPGA), or a programmable logic array (PLA), may be customized by utilizing the state information of the computer-readable program instructions, and the electronic circuit may execute the computer-readable program instructions, thereby realizing various aspects of the present disclosure.

[0084] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents, and any modifications or equivalent replacements that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A 220kV line differential protection channel hot switching simulation test method without abnormality, characterized in that: The steps include: Network two 220kV line differential protection devices and three OXC devices for operation; The three phases of the six-phase balanced load current are respectively output to the 220kV line differential protection devices on both sides, and the through load simulation test is performed on the 220kV line differential protection devices: The C-phase current of the unilateral 220kV line differential protection device is made to drop by 0.3A, so that the 220kV line differential protection device starts recording waveforms; When the 220kV line differential protection device starts recording, the optical fiber channel of the 220kV line differential protection device is switched; Obtain the protection waveform during the optical fiber channel switching and determine the status of the 220kV line differential protection device during the optical fiber channel switching process; By recording the waveform, the switching process of the differential protection channel is judged, and whether the differential protection is correctly locked and alarmed; If the differential protection is correctly locked and alarms during the channel switching process, it is judged that there is no abnormality in the hot switching process of the 220kV line differential protection channel; Conduct through-load simulation tests on the 220kV line differential protection device under different load conditions to determine whether the channel switching process of the 220kV line differential protection device under each load condition is normal; If there is no abnormality in the hot switching process of the 220kV line differential protection channel under all load conditions, the test is judged to have passed, otherwise the test has failed.

2. The 220kV line differential protection channel hot switching simulation test method according to claim 1 is characterized in that: The networking operation of two 220kV line differential protection devices and three OXC devices specifically includes: Three OXC devices are networked to form an OXC matrix, and two identical 220kV line differential protection devices are connected to the OXC matrix. Each 220kV line differential protection device is connected to one OXC device. The network management configuration works on the primary path by default. When the primary path fails, it switches to the backup channel through the preset backup route.

3. The 220kV line differential protection channel hot switching simulation test method according to claim 1 is characterized in that: The output of six-phase balanced load current to two 220kV line protections specifically includes: Use the relay protection tester to output six-phase balanced load current, among which three-phase currents are equal in magnitude and opposite in direction to the other three-phase currents; The relay tester outputs positive-sequence load currents of equal magnitude for the three phases A, B, and C to one 220kV line differential protection device, and outputs the other three-phase load currents of equal magnitude and opposite direction to another 220kV line differential protection device. At the same time, observe that the differential current in the two 220kV line differential protection devices is 0. If the differential current is not 0, check the wiring of the relay tester and correct it until the differential current in the two 220kV line differential protection devices is 0.

4. The 220kV line differential protection channel hot switching simulation test method according to claim 3 is characterized in that: The step of causing the phase C current of the single-side 220kV line differential protection device to drop by 0.3A so that the 220kV line differential protection device starts recording the waveform specifically includes: The C-phase current input to one of the 220kV line differential protection devices was reduced by 0.3A through the relay protection tester. At this time, the 220kV line differential protection device started recording due to the sudden change in current.

5. The 220kV line differential protection channel hot switching simulation test method according to claim 1 is characterized in that: When the 220kV line protection device is started, switching the optical fiber channel of the 220kV line differential protection device specifically includes: The OXC simulation program automatically switches the program to trigger the switch or manually triggers the optical fiber to automatically switch.

6. The 220kV line differential protection channel hot switching simulation test method according to claim 1 is characterized in that: The protection waveform during the optical fiber channel switching is captured to determine the protection status during the channel switching process, specifically including: The waveform recorded when the channel is switched in the 220kV line differential protection device is exported, and the sudden change of differential current of the differential protection at the time of channel switching is observed, and whether the differential protection is locked and alarmed is observed.

7. The 220kV line differential protection channel hot switching simulation test method according to claim 1 is characterized in that: If the channel switching process, the differential protection is correctly locked and alarmed, specifically includes: When confirming the moment of differential protection channel switching, if the differential protection function locking switch quantity and channel alarm switch quantity can be correctly realized, it is judged that there is no abnormality in the hot switching process of the 220kV line differential protection channel.

8. The 220kV line differential protection channel hot switching simulation test method according to claim 1 is characterized in that: The switching function under the simulation of different load states specifically includes: Carry out through load simulation test on 220kV line differential protection device when the load state is 0.5A, 1A, 3A, 5A, 10A, 15A, 18A, 20A respectively, and judge whether the channel switching process of 220kV line differential protection device is normal under each load state; If there is no abnormality in the hot switching process of the 220kV line differential protection channel under all load conditions, it is judged that the hot switching process of the 220kV line differential protection device channel is safe and reliable.

9. A 220kV line differential protection channel hot switching without abnormality simulation test system, used to implement the 220kV line differential protection channel hot switching without abnormality simulation test method according to any one of claims 1 to 8, characterized in that: include: Networking module, current output module, test module, judgment module; The networking module is used to network two 220kV line differential protection devices and three OXC devices; The current output module is used to output the three phases of the six-phase balanced load current to the 220kV line differential protection devices on both sides; The test module is used to perform a through load simulation test on the 220kV line differential protection device, including: making the C-phase current of the single-side 220kV line differential protection device drop by 0.3A, so that the 220kV line differential protection device starts recording; when the 220kV line differential protection device starts recording, the optical fiber channel of the 220kV line differential protection device is switched; the protection waveform when the optical fiber channel is switched is obtained, and the state of the 220kV line differential protection device during the optical fiber channel switching process is judged; the differential protection channel switching process is judged by the recording waveform, and whether the differential protection is correctly locked and alarmed; simulating the switching function under nine load conditions and performing through load simulation tests under different load conditions; The judgment module is used to judge whether the hot switching process of the 220kV line differential protection channel is abnormal: if the differential protection is correctly locked and alarmed during the channel switching process, it is judged that there is no abnormality in the hot switching process of the 220kV line differential protection channel; and to judge whether the 220kV line differential protection device has passed the test: if there is no abnormality in the hot switching process of the 220kV line differential protection channel under all load conditions, it is judged that the test has passed, otherwise the test has failed.

10. A terminal comprising a processor and a storage medium; characterized in that: The storage medium is used to store instructions; The processor is configured to operate according to the instructions to execute the steps of the method according to any one of claims 1-8.

11. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the steps of the method according to any one of claims 1 to 8 are implemented.

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