A method for transforming 500kV line intervals in smart substations by eliminating merging units

Abstract

The present invention relates to the technical field of image recognition of overhead power transmission lines, and discloses a method for modifying 500kV line intervals in a smart substation by eliminating merging units. The method is characterized in that it includes the following steps: S1. shutting down the intervals to be modified, including the 5011 circuit breaker interval, the 5012 circuit breaker interval, and the line interval, and switching primary and secondary related equipment from operation to maintenance; S2. implementing safety measures to isolate the modified equipment; S3. adding a fault recorder device and a power angle measurement device to the interval layer; S4. installing a new line voltage transfer panel to protect the transfer of indoor line voltage; and S5. modifying the line. The modification scheme proposed by the present invention eliminates the merging unit, allowing the interval layer equipment to be directly connected to a conventional mutual inductor via a cable to realize analog quantity acquisition, thereby solving the problem of related protection devices being locked or malfunctioning due to a malfunction of the merging unit and improving the reliability and stability of the smart station operation.

Description

Technical Field

[0001] The present invention relates to the technical field of power systems, and in particular to a method for transforming a 500kV line interval by canceling a merging unit in an intelligent substation. Background Art

[0002] With the implementation of State Grid Corporation of China's strategy for building a strong smart grid, smart substations have seen significant development. In the early stages of smart substation construction, most intelligent devices adopted a "conventional transformer + merging unit" sampling model. Conventional transformers refer to traditional electromagnetic current transformers or voltage transformers, which convert high primary system voltages into low voltages and high currents into low currents for measurement or protection systems. The merging unit is the core component for digital sampling in smart substations. It changes the traditional substation cable wiring model and can convert analog quantities collected from devices such as voltage transformers and current transformers into digital quantities, enabling functions such as analog quantity acquisition, data cascading, voltage switching, and voltage paralleling. The data information is then sent to various devices such as protection, measurement and control, and wave recording devices through direct acquisition or networking via standard protocols. The merging unit facilitates the digitization and networking of substations.

[0003] After a period of operation, various problems existing in the "conventional transformer + merging unit" sampling mode have gradually been exposed.

[0004] (1) Abnormal merging unit synchronization. The merging unit converts the collected voltage and current analog values ​​into digital values ​​through filtering and analog-to-digital conversion, and then transmits them to the protection device through the optical fiber link. Delays occur in the sampling link, and the protection device needs to synchronize the merging unit data. When a synchronization abnormality occurs, it will cause the protection device to lock or malfunction.

[0005] (2) Merging unit SV link break failure. SV data needs to be transmitted through the optical fiber link. When a merging unit failure, optical port damage, or optical fiber breakage occurs, it will cause an SV link break failure. At this time, the relevant protection device will not be able to collect any sampling data and will be locked.

[0006] (3) Inconsistency in the dual A / D sampling of the merging unit. To ensure the reliability of A / D sampling, the merging unit uses dual A / D sampling. The protection device compares the received dual A / D data and only considers the sampling valid if it falls within the error range. If a merging unit failure causes inconsistent dual A / D sampling, the relevant protection device will be locked.

[0007] (4) Invalid merging unit sampling. The merging unit will judge the SV quality of the sampled value. When a merging unit failure causes data abnormality, the SV message quality bit will be set to invalid, and the relevant protection device will be locked.

[0008] (5) Poor debugging quality of the merged unit. Since the debugging process of the merged unit must be carried out using the dedicated software of the corresponding manufacturer, the debugging process is largely dependent on the manufacturer, resulting in complex debugging and low debugging quality, making it difficult to ensure the debugging quality of the merged unit.

[0009] The stability and reliability of the merging unit operation directly affect the reliability of the secondary system operation. When a merging unit fails, it will cause the related protection devices to lock or malfunction, and the scope of influence will expand. In recent years, during the operation of smart stations, many power grid failures caused by merging units have occurred, seriously affecting the safe and stable operation of the power grid. The first batch of smart stations have been in operation for 10 years, and the protection equipment is facing transformation and upgrading. The proposal of a smart station transformation plan is imminent. The present invention proposes a protection transformation method to eliminate the merging unit for a 500kV line interval in a semi-connected type and "conventional transformer + merging unit" sampling mode in a smart substation. The cable connection scheme is used to eliminate the intermediate link of the merging unit and improve the stability and reliability of the power grid operation. Summary of the Invention

[0010] (1) Technical problems solved

[0011] In order to solve the problem that the stability and reliability of the operation of the merging unit directly affect the reliability of the operation of the secondary system, when a merging unit fails, it will cause the relevant protection devices to be locked or malfunctioned, and the impact range will be expanded. The present invention provides a method for the transformation of the 500kV line interval by eliminating the merging unit, which solves the problems raised in the above background technology.

[0012] (2) Technical solution

[0013] To achieve the above objectives, the present invention is implemented through the following technical solutions: A method for transforming a 500kV line interval in an intelligent substation by canceling a merging unit comprises the following steps:

[0014] The power supply to the intervals to be renovated will be shut down, including the 5011 circuit breaker interval, the 5012 circuit breaker interval and the line interval, and the primary and secondary related equipment will be transferred from operation to maintenance.

[0015] As a further solution of the present invention, to avoid affecting the running equipment during the transformation process, safety measures need to be implemented to isolate the transformed equipment, which can be divided into the following situations:

[0016] a. When the line string is complete, it is necessary to exit the 5012 circuit breaker protection to start the running line remote trip GOOSE sending soft pressure plate and the failure trip 5013 circuit breaker GOOSE sending soft pressure plate, exit the 5011 circuit breaker protection to start the bus differential failure GOOSE sending soft pressure plate, exit the running line protection 5011 circuit breaker SV receiving soft pressure plate, exit the 500kV#1 busbar protection 5011 circuit breaker SV receiving soft pressure plate and GOOSE failure receiving soft pressure plate, and at the same time disconnect the optical fiber link corresponding to the above loop;

[0017] b. When the line transformer string is complete, it is necessary to exit the 5012 circuit breaker protection failure-tripping GOOSE sending soft pressure plate on the three sides of the main transformer and the failure-tripping GOOSE sending soft pressure plate on the 5013 circuit breaker, exit the 5011 circuit breaker protection failure GOOSE sending soft pressure plate, exit the running main transformer protection 5011 circuit breaker SV receiving soft pressure plate and the failure-tripping GOOSE receiving soft pressure plate on the three sides of the main transformer, exit the 500kV#1 busbar protection 5011 circuit breaker SV receiving soft pressure plate and the GOOSE failure receiving soft pressure plate, and at the same time disconnect the optical fiber link corresponding to the above loop;

[0018] c. When it is an incomplete string, it is necessary to exit the 5012 circuit breaker protection start-up differential failure GOOSE sending soft pressure plate, exit the 5011 circuit breaker protection start-up differential failure GOOSE sending soft pressure plate, exit the 500kV#2 busbar protection 5012 circuit breaker SV receiving soft pressure plate and GOOSE failure receiving soft pressure plate, exit the 500kV#1 busbar protection 5011 circuit breaker SV receiving soft pressure plate and GOOSE failure receiving soft pressure plate, and at the same time disconnect the optical fiber link corresponding to the above loop.

[0019] New fault recorders and power angle measurement devices have been added to the bay level. These devices support conventional transformer sampling and GOOSE functionality, using the IEC61850 communication protocol. The fault recorders are dual-configured. These utility devices will only be connected to the corresponding bays during this renovation, with additional bays to be added as subsequent renovations are completed.

[0020] A new line voltage transfer panel is installed to protect the transfer of indoor line voltage.

[0021] During the renovation process, the line protection device, circuit breaker protection device, circuit breaker measurement and control device (the side circuit breaker measurement and control device is also used for line measurement and control), and electricity meter were replaced. After the replacement, the device supports conventional transformer sampling and GOOSE functions, and adopts the IEC61850 communication protocol.

[0022] The line protection is configured in a dual configuration, with integrated primary and backup protection, including overvoltage protection and remote tripping and local discrimination functions. The current and voltage are directly connected through cables, and the tripping adopts the GOOSE direct tripping method. The starting failure is transmitted through the process layer GOOSE network. The circuit breaker protection is configured in a dual configuration, including failure protection and reclosing functions. The reclosing does not consider the synchronization check function. The tripping adopts the GOOSE direct tripping method, and the starting failure, remote start transmission, and failure linkage tripping are transmitted through the process layer GOOSE network.

[0023] During the transformation process, the 5011 smart terminal and 5012 smart terminal were replaced simultaneously.

[0024] The previous 5011 merging unit needs to be retained, and the 500kV#1 busbar protection adjacent to the 5011 circuit breaker still uses the previous device, and the required current is sampled by the previous merging unit for SV.

[0025] The previous 5012 merging unit needs to be retained, and the adjacent in-service line protection (main transformer protection or busbar protection), measurement and control devices and electricity meters of the 5012 circuit breaker still use the previous devices, and the required current is sampled through the previous merging unit.

[0026] As a further embodiment of the present invention,

[0027] After the line is shut down, the following cables need to be newly laid at the current transformer of the 5011 circuit breaker:

[0028] a. Lay the cable from the 5011 circuit breaker current transformer to line protection 1;

[0029] b. Lay the cable from the 5011 circuit breaker current transformer to line protection 2;

[0030] c. Lay the cable from the 5011 circuit breaker current transformer to the 5011 circuit breaker protection 1. This circuit is then connected in series from the 5011 circuit breaker protection 1 to the 5011 circuit breaker protection 2. The 5011 circuit breaker protection 2 is connected in series to the fault recorder 1. The fault recorder 1 is connected in series to the fault recorder 2.

[0031] d. Lay the cable from the 5011 circuit breaker current transformer to the 5011 circuit breaker measurement and control device;

[0032] e. Lay the cable from the 5011 circuit breaker current transformer to the electricity meter.

[0033] As a further embodiment of the present invention,

[0034] After the line is shut down, the following cables need to be newly laid at the current transformer of the 5012 circuit breaker:

[0035] a. Lay the cable from the current transformer of the 5012 circuit breaker to the line protection 1, take the line closing current with the current of the 5011 circuit breaker, and then connect it in series with the fault recorder 1 through the line protection 1;

[0036] b. Lay the cable from the 5012 circuit breaker current transformer to the line protection 2, take the line total current from the 5011 circuit breaker current, and then connect it in series with the fault recorder 2 through the line protection 2. The fault recorder 2 is connected in series with the traveling wave ranging device, where the traveling wave ranging uses the previous device;

[0037] c. Lay the cable from the 5012 circuit breaker current transformer to the 5012 circuit breaker protection 1. This circuit is then connected in series from the 5012 circuit breaker protection 1 to the 5012 circuit breaker protection 2. The 5012 circuit breaker protection 2 is connected in series to the fault recorder 1. The fault recorder 1 is connected in series to the fault recorder 2.

[0038] d. Lay the cable from the 5012 circuit breaker current transformer to the 5012 circuit breaker measurement and control device. This circuit is then connected in series to the power angle measurement device after the 5012 circuit breaker measurement and control device and the 5011 circuit breaker measurement and control device take the closing current.

[0039] e. Lay the cable from the current transformer of the side circuit breaker to the electricity meter.

[0040] After the line is shut down for an interval, a new cable from the line voltage transformer to the line voltage transfer panel needs to be laid at the line voltage transformer, and then connected to the fault recorder 1, fault recorder 2, power angle measurement device, line protection 1, line protection 2, and measurement and control device through the line voltage transfer panel.

[0041] During line interval reconstruction, it is necessary to reconfigure the SCD file of the entire station, generate a new project configuration CID file for the reconstructed equipment and newly added equipment, and complete the debugging and transmission of the above-mentioned line protection devices, circuit breaker protection devices, measurement and control devices, fault recorders, intelligent terminals and other equipment after downloading.

[0042] For relevant equipment in operation, a rotational shutdown method is required to update protection configuration and equipment transmission.

[0043] When the 5011 circuit breaker is connected to the 500kV#1 busbar protection, it is necessary to shut down the relevant primary busbar equipment, update the CID file configuration of the shut-down busbar protection, complete the entire group of debugging and transmission work for the busbar protection and transformation bays and other circuit breaker bays connected to the busbar, and link the primary equipment during debugging.

[0044] As a further embodiment of the present invention,

[0045] When connecting a 5012 circuit breaker to an in-service protection device, the following situations apply:

[0046] a. When the line is complete, shut down the relevant line intervals, update the CID file configuration of the shut-down line protection, circuit breaker protection, and intelligent terminal, complete the commissioning and transmission of the shut-down line protection, shut-down circuit breaker protection, and modified interval protection devices, and link the primary equipment during commissioning;

[0047] b. When the line transformer is complete, shut down the relevant main transformer bays, update the shutdown main transformer protection and circuit breaker protection, and the CID file configuration of the intelligent terminal, complete the debugging and transmission work of the entire group of shutdown main transformer protection, shutdown circuit breaker protection and modified bay protection devices, and link the primary equipment during debugging;

[0048] c. When it is an incomplete string, shut down the relevant primary busbar equipment, update the CID file configuration of the shut down busbar protection, complete the debugging and transmission work of the entire group of shut down busbar protection and modified interval protection devices and other circuit breaker intervals connected to the busbar, and link the primary equipment during debugging.

[0049] After completing the above access work, the 500kV line interval transformation was completed.

[0050] (3) Beneficial effects

[0051] The present invention provides a method for transforming a 500kV line interval in an intelligent substation by eliminating merging units, which has the following beneficial effects:

[0052] When smart stations adopt the "conventional transformer + merging unit mode," the sampling process for protection devices is artificially increased, reducing the operational reliability of the bay-level equipment. Existing smart station renovation solutions only replace and upgrade the original equipment, without changing the "conventional transformer + merging unit" sampling mode, and fail to fundamentally address the hidden dangers of the merging unit transmission link. The renovation solution proposed in this invention eliminates the merging unit, allowing bay-level equipment to directly connect to conventional transformers via cables for analog data acquisition. This solves the problem of merging unit failures causing related protection devices to lock out or malfunction, thereby improving the reliability and stability of smart station operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 This is the line interval reconstruction flow chart;

[0054] Figure 2 Schematic diagram of the sampling circuit modification to eliminate the merging unit at line intervals. DETAILED DESCRIPTION

[0055] To make the purpose, technical solutions and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them.

[0056] Therefore, the following detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely represents some embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort shall fall within the scope of protection of the present invention.

[0057] Example 1

[0058] See also Figures 1 to 2 The present invention provides a technical solution: a method for transforming a 500kV line interval in an intelligent substation by canceling a merging unit, comprising the following steps:

[0059] The power supply to the intervals to be renovated will be shut down, including the 5011 circuit breaker interval, the 5012 circuit breaker interval and the line interval, and the primary and secondary related equipment will be transferred from operation to maintenance.

[0060] To avoid affecting the running equipment during the renovation process, safety measures must be implemented to isolate the renovated equipment, which can be divided into the following situations:

[0061] a. When the line string is complete, it is necessary to exit the 5012 circuit breaker protection to start the running line remote trip GOOSE sending soft pressure plate and the failure trip 5013 circuit breaker GOOSE sending soft pressure plate, exit the 5011 circuit breaker protection to start the bus differential failure GOOSE sending soft pressure plate, exit the running line protection 5011 circuit breaker SV receiving soft pressure plate, exit the 500kV#1 busbar protection 5011 circuit breaker SV receiving soft pressure plate and GOOSE failure receiving soft pressure plate, and at the same time disconnect the optical fiber link corresponding to the above loop;

[0062] b. When the line transformer string is complete, it is necessary to exit the 5012 circuit breaker protection failure-tripping GOOSE sending soft pressure plate on the three sides of the main transformer and the failure-tripping GOOSE sending soft pressure plate on the 5013 circuit breaker, exit the 5011 circuit breaker protection failure GOOSE sending soft pressure plate, exit the running main transformer protection 5011 circuit breaker SV receiving soft pressure plate and the failure-tripping GOOSE receiving soft pressure plate on the three sides of the main transformer, exit the 500kV#1 busbar protection 5011 circuit breaker SV receiving soft pressure plate and the GOOSE failure receiving soft pressure plate, and at the same time disconnect the optical fiber link corresponding to the above loop;

[0063] c. When it is an incomplete string, it is necessary to exit the 5012 circuit breaker protection starter differential failure GOOSE sending soft pressure plate, exit the 5011 circuit breaker protection starter differential failure GOOSE sending soft pressure plate, exit the 500kV#2 busbar protection 5012 circuit breaker SV receiving soft pressure plate and GOOSE failure receiving soft pressure plate, exit the 500kV#1 busbar protection 5011 circuit breaker SV receiving soft pressure plate and GOOSE failure receiving soft pressure plate, and disconnect the optical fiber link corresponding to the above loop at the same time;

[0064] New fault recorders and power angle measurement devices have been added to the bay level. These devices support conventional transformer sampling and GOOSE functionality, using the IEC61850 communication protocol. The fault recorders are dual-configured. These utility devices will only be connected to the corresponding bays during this renovation, with additional bays to be added as subsequent renovations are completed.

[0065] A new line voltage transfer panel is installed to protect the transfer of indoor line voltage.

[0066] During the renovation process, the line protection device, circuit breaker protection device, circuit breaker measurement and control device (the side circuit breaker measurement and control device is also used for line measurement and control), and electricity meter were replaced. After the replacement, the device supports conventional transformer sampling and GOOSE functions, and adopts the IEC61850 communication protocol.

[0067] The line protection is configured in a dual configuration, with integrated primary and backup protection, including overvoltage protection and remote tripping and local discrimination functions. The current and voltage are directly connected through cables, and the tripping adopts the GOOSE direct tripping method. The starting failure is transmitted through the process layer GOOSE network. The circuit breaker protection is configured in a dual configuration, including failure protection and reclosing functions. The reclosing does not consider the synchronization check function. The tripping adopts the GOOSE direct tripping method, and the starting failure, remote start transmission, and failure linkage tripping are transmitted through the process layer GOOSE network.

[0068] Example 2

[0069] Compared with Example 1, based on Example 1,

[0070] During the transformation process, the 5011 smart terminal and 5012 smart terminal were replaced simultaneously.

[0071] The previous 5011 merging unit needs to be retained, and the 500kV#1 busbar protection adjacent to the 5011 circuit breaker still uses the previous device, and the required current is sampled by the previous merging unit for SV.

[0072] The previous 5012 merging unit needs to be retained, and the adjacent in-service line protection (main transformer protection or busbar protection), measurement and control devices and electricity meters of the 5012 circuit breaker still use the previous devices, and the required current is sampled through the previous merging unit.

[0073] After the line is shut down, the following cables need to be newly laid at the current transformer of the 5011 circuit breaker:

[0074] a. Lay the cable from the 5011 circuit breaker current transformer to line protection 1;

[0075] b. Lay the cable from the 5011 circuit breaker current transformer to line protection 2;

[0076] c. Lay the cable from the 5011 circuit breaker current transformer to the 5011 circuit breaker protection 1. This circuit is then connected in series from the 5011 circuit breaker protection 1 to the 5011 circuit breaker protection 2. The 5011 circuit breaker protection 2 is connected in series to the fault recorder 1. The fault recorder 1 is connected in series to the fault recorder 2.

[0077] d. Lay the cable from the 5011 circuit breaker current transformer to the 5011 circuit breaker measurement and control device;

[0078] e. Lay the cable from the 5011 circuit breaker current transformer to the electricity meter.

[0079] Example 3

[0080] Compared with Example 2, based on Example 2,

[0081] After the line is shut down, the following cables need to be newly laid at the current transformer of the 5012 circuit breaker:

[0082] a. Lay the cable from the current transformer of the 5012 circuit breaker to the line protection 1, take the line closing current with the current of the 5011 circuit breaker, and then connect it in series with the fault recorder 1 through the line protection 1;

[0083] b. Lay the cable from the 5012 circuit breaker current transformer to the line protection 2, take the line total current from the 5011 circuit breaker current, and then connect it in series with the fault recorder 2 through the line protection 2. The fault recorder 2 is connected in series with the traveling wave ranging device, where the traveling wave ranging uses the previous device;

[0084] c. Lay the cable from the 5012 circuit breaker current transformer to the 5012 circuit breaker protection 1. This circuit is then connected in series from the 5012 circuit breaker protection 1 to the 5012 circuit breaker protection 2. The 5012 circuit breaker protection 2 is connected in series to the fault recorder 1. The fault recorder 1 is connected in series to the fault recorder 2.

[0085] d. Lay the cable from the 5012 circuit breaker current transformer to the 5012 circuit breaker measurement and control device. This circuit is then connected in series to the power angle measurement device after the 5012 circuit breaker measurement and control device and the 5011 circuit breaker measurement and control device take the closing current.

[0086] e. Lay the cable from the current transformer of the side circuit breaker to the electricity meter.

[0087] After the line is shut down for an interval, a new cable from the line voltage transformer to the line voltage transfer panel needs to be laid at the line voltage transformer, and then connected to the fault recorder 1, fault recorder 2, power angle measurement device, line protection 1, line protection 2, and measurement and control device through the line voltage transfer panel.

[0088] During line interval reconstruction, it is necessary to reconfigure the SCD file of the entire station, generate a new project configuration CID file for the reconstructed equipment and newly added equipment, and complete the debugging and transmission of the above-mentioned line protection devices, circuit breaker protection devices, measurement and control devices, fault recorders, intelligent terminals and other equipment after downloading.

[0089] For relevant equipment in operation, a rotational shutdown method is required to update protection configuration and equipment transmission.

[0090] When the 5011 circuit breaker is connected to the 500kV#1 busbar protection, it is necessary to shut down the relevant primary busbar equipment, update the CID file configuration of the shut-down busbar protection, complete the entire group of debugging and transmission work for the busbar protection and transformation bays and other circuit breaker bays connected to the busbar, and link the primary equipment during debugging.

[0091] When connecting a 5012 circuit breaker to an in-service protection device, the following situations apply:

[0092] a. When the line is complete, shut down the relevant line intervals, update the CID file configuration of the shut-down line protection, circuit breaker protection, and intelligent terminal, complete the commissioning and transmission of the shut-down line protection, shut-down circuit breaker protection, and modified interval protection devices, and link the primary equipment during commissioning;

[0093] b. When the line transformer is complete, shut down the relevant main transformer bays, update the shutdown main transformer protection and circuit breaker protection, and the CID file configuration of the intelligent terminal, complete the debugging and transmission work of the entire group of shutdown main transformer protection, shutdown circuit breaker protection and modified bay protection devices, and link the primary equipment during debugging;

[0094] c. When it is an incomplete string, shut down the relevant primary busbar equipment, update the CID file configuration of the shut down busbar protection, complete the debugging and transmission work of the entire group of shut down busbar protection and modified interval protection devices and other circuit breaker intervals connected to the busbar, and link the primary equipment during debugging.

[0095] After completing the above access work, the 500kV line interval transformation was completed.

[0096] When smart stations adopt the "conventional transformer + merging unit mode," the sampling process for protection devices is artificially increased, reducing the operational reliability of the bay-level equipment. Existing smart station renovation solutions only replace and upgrade the original equipment, without changing the "conventional transformer + merging unit" sampling mode, and fail to fundamentally address the hidden dangers of the merging unit transmission link. The renovation solution proposed in this invention eliminates the merging unit, allowing bay-level equipment to directly connect to conventional transformers via cables for analog data acquisition. This solves the problem of merging unit failures causing related protection devices to lock out or malfunction, thereby improving the reliability and stability of smart station operation.

[0097] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for transforming 500kV line intervals in a smart substation by canceling merging units, characterized in that: The process includes the following steps: S1. Shut down the power supply to the interval to be renovated, including the 5011 circuit breaker interval, the 5012 circuit breaker interval, and the line interval, and switch the primary and secondary related equipment from operation to maintenance; S2. Implement safety measures to isolate the renovated equipment. Isolation of the renovated equipment is divided into the following situations: a. When the line string is complete, it is necessary to exit the 5012 circuit breaker protection to start the running line remote trip GOOSE sending soft pressure plate and the failure trip 5013 circuit breaker GOOSE sending soft pressure plate, exit the 5011 circuit breaker protection to start the bus differential failure GOOSE sending soft pressure plate, exit the running line protection 5011 circuit breaker SV receiving soft pressure plate, exit the 500kV#1 busbar protection 5011 circuit breaker SV receiving soft pressure plate and GOOSE failure receiving soft pressure plate, and at the same time disconnect the optical fiber link corresponding to the above loop; b. When the line transformer string is complete, it is necessary to exit the 5012 circuit breaker protection failure-tripping GOOSE sending soft pressure plate on the three sides of the main transformer and the failure-tripping GOOSE sending soft pressure plate on the 5013 circuit breaker, exit the 5011 circuit breaker protection failure GOOSE sending soft pressure plate, exit the running main transformer protection 5011 circuit breaker SV receiving soft pressure plate and the failure-tripping GOOSE receiving soft pressure plate on the three sides of the main transformer, exit the 500kV#1 busbar protection 5011 circuit breaker SV receiving soft pressure plate and the GOOSE failure receiving soft pressure plate, and at the same time disconnect the optical fiber link corresponding to the above loop; c. When the string is incomplete, the 5012 circuit breaker protection bus differential failure GOOSE sending soft pressure plate is removed, the 5011 circuit breaker protection bus differential failure GOOSE sending soft pressure plate is removed, the 500kV#2 busbar protection 5012 circuit breaker SV receiving soft pressure plate and GOOSE failure receiving soft pressure plate are removed, the 500kV#1 busbar protection 5011 circuit breaker SV receiving soft pressure plate and GOOSE failure receiving soft pressure plate are removed, and the optical fiber links corresponding to the above loops are disconnected at the same time; S3. A conventional sampling fault recorder device and power angle measurement device are added to the bay layer; S4. New line voltage transfer panel is installed to protect the transfer of indoor line voltage; S5. Renovate the line bay layer equipment. During the renovation process, replace the line protection device, circuit breaker protection device, circuit breaker measurement and control device, and electricity meter. During the renovation process, replace the 5011 smart terminal and 5012 smart terminal simultaneously. Retain the previous 5011 merging unit. The 500kV#1 busbar protection adjacent to the 5011 circuit breaker still uses the previous device, and the required current is sampled through the previous merging unit for SV. Retain the previous 5012 merging unit. The protection, measurement and control devices and electricity meters of the in-service lines adjacent to the 5012 circuit breaker still use the previous devices, and the required current is sampled through the previous merging unit.

2. A method for transforming a 500kV line interval into a merging unit in a smart substation according to claim 1, characterized in that: In S3, the fault recorder device and power angle measurement device support conventional transformer sampling and GOOSE functions, adopt the IEC61850 communication protocol, and the fault recorder is a dual configuration.

3. A method for transforming a 500kV line interval into a merging unit in a smart substation according to claim 1, characterized in that: In S5, the replaced device supports conventional transformer sampling and GOOSE functions, and adopts the IEC61850 communication protocol; the line protection is configured in a dual manner, with main and backup integrated protection, including overvoltage protection and remote tripping local judgment function, the current and voltage are directly connected through cables, the tripping adopts the GOOSE direct tripping method, and the starting failure is transmitted through the process layer GOOSE network; the circuit breaker protection is configured in a dual manner, including failure protection and reclosing function, the reclosing does not consider the synchronization check function, the tripping adopts the GOOSE direct tripping method, and the starting failure, starting remote transmission, and failure joint tripping are transmitted through the process layer GOOSE network.

4. A method for transforming a 500kV line interval by eliminating merging units in a smart substation according to claim 3, characterized in that: In step S5, after the line is shut down, the following cables need to be newly laid at the current transformer of the 5011 circuit breaker: a. Lay the cable from the 5011 circuit breaker current transformer to line protection 1; b. Lay the cable from the 5011 circuit breaker current transformer to line protection 2; c. Lay the cable from the 5011 circuit breaker current transformer to the 5011 circuit breaker protection 1. This circuit is then connected in series from the 5011 circuit breaker protection 1 to the 5011 circuit breaker protection 2. The 5011 circuit breaker protection 2 is connected in series to the fault recorder 1. The fault recorder 1 is connected in series to the fault recorder 2. d. Lay the cable from the 5011 circuit breaker current transformer to the 5011 circuit breaker measurement and control device; e. Lay the cable from the 5011 circuit breaker current transformer to the electricity meter.

5. A method for transforming a 500kV line interval by eliminating merging units in a smart substation according to claim 4, characterized in that: In step S5, after the line is shut down, the following cables need to be newly laid at the current transformer of the 5012 circuit breaker: a. Lay the 5012 circuit breaker current transformer to the line protection cable, take the line closing current together with the 5011 circuit breaker current, and then connect it in series with the fault recorder through the line protection; b. Lay the 5012 circuit breaker current transformer to the line protection cable, take the line total current together with the 5011 circuit breaker current, and then connect it in series with the fault recorder through the line protection, and connect the fault recorder in series with the traveling wave ranging device, where the traveling wave ranging uses the previous device; c. Lay the cable from the 5012 circuit breaker current transformer to the 5012 circuit breaker protection cable. The 5012 circuit breaker protection cable is then connected in series to the 5012 circuit breaker protection cable, which is then connected in series to fault recorder 1. Fault recorder 1 is then connected in series to fault recorder 2. d. Lay the cable from the 5012 circuit breaker current transformer to the 5012 circuit breaker measurement and control device. This circuit is then connected in series to the power angle measurement device after the 5012 circuit breaker measurement and control device and the 5011 circuit breaker measurement and control device take the closing current. e. Lay the cable from the current transformer of the side circuit breaker to the electricity meter.

6. A method for transforming a 500kV line interval by eliminating merging units in a smart substation according to claim 5, characterized in that: In step S5, after the line is shut down, a new line voltage transformer to line voltage transfer panel cable needs to be laid at the line voltage transformer, and then connected to the fault recorder, power angle measurement device, line protection, and measurement and control device through the line voltage transfer panel.

7. A method for transforming a 500kV line interval by eliminating merging units in a smart substation according to claim 6, characterized in that: In step S5, during line interval reconstruction, the entire station SCD file needs to be reconfigured, and a new project configuration CID file is generated for the reconstructed and newly added equipment. After downloading, the above-mentioned line protection devices, circuit breaker protection devices, measurement and control devices, fault recorders, and intelligent terminal devices are debugged and operated. For relevant in-service equipment, the protection configuration update and equipment operation need to be carried out in a rotational manner. When connecting the 5011 circuit breaker to the 500kV#1 busbar protection, it is necessary to shut down the relevant primary busbar equipment, update the CID file configuration of the shut-down busbar protection, complete the entire group commissioning and transmission work of the busbar protection and transformation bays and other circuit breaker bays connected to the busbar, and link the primary equipment during commissioning; When connecting a 5012 circuit breaker to an in-service protection device, the following situations apply: a. When the line is complete, shut down the relevant line intervals, update the CID file configuration of the shut-down line protection, circuit breaker protection, and intelligent terminal, complete the commissioning and transmission of the shut-down line protection, shut-down circuit breaker protection, and modified interval protection devices, and link the primary equipment during commissioning; b. When the line transformer is complete, shut down the relevant main transformer bays, update the shutdown main transformer protection and circuit breaker protection, and the CID file configuration of the intelligent terminal. Complete the entire set of commissioning and transmission work for the shutdown main transformer protection, shutdown circuit breaker protection, and modified bay protection devices, and link the primary equipment during commissioning; c. If the string is incomplete, shut down the relevant primary busbar equipment, update the CID file configuration of the shut-down busbar protection, complete the debugging and transmission work of the entire group of shut-down busbar protection and modified bay protection devices and other circuit breaker bays connected to the busbar, and link the primary equipment during debugging.

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