A control method for switching off a small power source of a regional power grid in cooperation with a backup automatic switching device

Abstract

The present invention relates to a system for interlocking and cutting small power sources in a regional power grid in cooperation with a standby automatic switching device, comprising: an intelligent terminal for interlocking and cutting, used to receive the GOOSE tripping command of the main power supply switch intelligent terminal and the standby automatic switching device, and to send a tripping node to complete the cutting of each small power supply circuit in the upper-level substation; an upper-level longitudinal remote transmission device, used to receive the interlocking and cutting node signal sent by the intelligent terminal for interlocking and cutting, and to send the received interlocking and cutting node signal to the lower-level longitudinal remote transmission device; a lower-level longitudinal remote transmission device, used to receive the interlocking and cutting node signal sent by the upper-level longitudinal remote transmission device, and to send a tripping node to complete the cutting of each small power supply circuit in the lower-level substation. The present invention can rely on the intra-station optical fiber communication and the optical fiber communication of the inter-station longitudinal remote transmission device to accurately cut off the small power sources of various levels of multiple substations in the regional power grid that affect the standby automatic switching, avoid the load erroneous cutting caused by the conventional standby automatic switching and cut-off, and ensure the uninterrupted power supply of important loads.

Description

Technical Field

[0001] The present invention relates to the technical field of new energy control and protection, and in particular to a control method for switching a small power source of a regional power grid in conjunction with a standby automatic switching device. Background Art

[0002] With rapid socioeconomic development, power users are increasingly demanding higher reliability from the grid, leading to an increasing number of substations equipped with multi-circuit power supply lines. Automatic backup activation devices are playing an increasingly important role in improving power supply reliability. When the primary power source fails, the automatic backup activation device activates, closing the backup source circuit breaker, allowing the backup source to resume power and ensure continuity. Simultaneously, with the development of new power systems and the high proportion of renewable energy connected to the grid, traditional grids are facing higher demands for their capacity, safety, and stability. The high penetration of small power sources poses new challenges to the normal operation of traditional grid safety and automation equipment, such as automatic backup activation devices and reclosing devices. For example, to prevent asynchronous reclosing after the automatic backup activation device activates, it simultaneously disconnects all grid-connected power lines at the substation level. As more and more small power sources are connected through lower-level low-voltage substations, directly disconnecting all grid-connected small power sources at the upper substation would result in unnecessary load losses at the lower substation.

[0003] Therefore, in substations where small power sources are centrally connected, line protection actions, main transformer protection actions, and standby automatic switching actions must first cut off the small power source to prevent affecting the acquisition of the no-voltage judgment criteria for the standby automatic switching test, avoid possible asynchronous closing, and restore power supply in time to ensure the safe and stable operation of the power grid system.

[0004] For example, the current conventional approach of connecting a 35kV or 10kV small power source to a 220kV substation via a downstream 110kV substation presents the following drawbacks: First, the upstream substation cannot directly implement cross-station interlocking of the 35kV or 10kV small power source connected to the downstream substation via relay protection equipment. Instead, the interconnecting lines between the upstream and downstream substations must be disconnected first, and then the interconnecting circuits in the downstream substation can be used to disconnect the relevant small power source. However, interconnecting the downstream substations can cause other important loads to lose power, reducing the reliability of the regional power grid. Second, interconnecting the grid-connected power source circuit is generally initiated directly by protection devices. When the number of renewable energy sources connected to the substation and the number of protection devices requiring interconnection are large, the interconnection logic and secondary circuit design become complex, hindering commissioning. Third, the protection interconnection circuits are often constructed using relay circuits. When the secondary circuits are complex, the substations have excessive cabling, which is inconsistent with the technological development trend of digital and intelligent substations. Summary of the Invention

[0005] In order to solve the problem of incorrect load shedding caused by conventional standby automatic switching, the purpose of the present invention is to provide a control method for the joint switching of small power sources in the regional power grid that can accurately cut off the small power sources of multiple substations in the regional power grid that affect the standby automatic switching, thereby ensuring the reliable power supply of important loads.

[0006] To achieve the above object, the present invention adopts the following technical solution: a control method for switching a small power source of a regional power grid in conjunction with a backup automatic switching device, the method comprising the following steps in sequence:

[0007] (1) If the external power grid fault causes the main power switch of the upper substation to trip, the various protection devices will send protection action commands to the intelligent terminal of the main power switch; the intelligent terminal of the main power switch will transmit its own TJQ, TJR, TJF trip GOOSE signals to the joint switching intelligent terminal through the optical cable;

[0008] (2) If the external power grid failure causes the main power supply of the upper substation to lose power, and the standby automatic switching device meets the corresponding starting conditions, the standby automatic switching device sends a GOOSE signal for joint switching to the joint switching intelligent terminal through the optical cable;

[0009] (3) The intelligent terminal for joint switching receives the GOOSE signals of step (1) and step (2), and after logical judgment, sends the tripping node to the upper-level substation to access the circuit breaker operation circuit of each interval of small power source 1 to small power source n and the upper-level longitudinal remote transmission device;

[0010] (4) The upper substation is connected to the circuit breaker operation circuits of each interval of small power source 1 to small power source n to complete the disconnection of each small power source circuit in the upper substation;

[0011] (5) The upper longitudinal remote transmission device sends the cut-off node signal to the lower longitudinal remote transmission device through the protection channel directly connected by optical cable or the multiplexed communication connection equipment. The lower longitudinal remote transmission device sends the trip node to the lower substation to access the circuit breaker operation circuits of each interval of small power source 1 to small power source n, thereby cutting off the small power source circuits in the lower substation;

[0012] The joint-cutting intelligent terminal is used to receive GOOSE tripping commands from the main power supply switch intelligent terminal and the standby automatic switching device, and issue a tripping node to complete the disconnection of each small power supply circuit in the upper-level substation; the joint-cutting intelligent terminal is installed at the upper-level substation end; the standby automatic switching device is a conventional standby automatic switching device, suitable for incoming lines or main transformer standby switching when one power supply is in operation and the other power supply is in standby; it is also suitable for incoming lines or main transformer standby switching when two power supplies are in operation, segmented tripping, and a busbar voltage loss;

[0013] The upper-level longitudinal remote transmission device is used to receive the inter-cut node signal sent by the inter-cutting intelligent terminal and send the received inter-cut node signal to the lower-level longitudinal remote transmission device; the upper-level longitudinal remote transmission device is installed at the upper-level substation end;

[0014] The lower-level longitudinal remote transmission device is used to receive the inter-cut node signal sent by the upper-level longitudinal remote transmission device and send a trip node to complete the removal of each small power supply circuit in the lower-level substation; the lower-level longitudinal remote transmission device is installed at the lower-level substation end;

[0015] The intelligent terminal for joint cutting sends a joint cutting node signal to the upper-level longitudinal remote transmission device. The upper-level longitudinal remote transmission device and the lower-level longitudinal remote transmission device are directly connected via a dedicated protection channel optical cable or multiplexed connection via communication equipment. The intelligent terminal for joint cutting communicates with the substation monitoring system in a two-way manner.

[0016] The joint-cutting intelligent terminal includes an optical input module, a switch input module, a logic judgment module, a switch output module, a communication module and a power module; the power module supplies power to the optical input module, the switch input module, the logic judgment module, the switch output module and the communication module respectively; the optical input module receives the GOOSE tripping command issued by the main power switch intelligent terminal and the standby automatic transfer device through a direct connection with an optical cable; the switch input module receives the tripping command of the main power switch intelligent terminal or the standby automatic transfer device through a switch node signal; the output ends of the optical input module and the switch input module are both connected to the input end of the logic judgment module, and the output end of the logic judgment module is respectively connected to the input end of the switch output module and the communication module, the communication module communicates bidirectionally with the substation monitoring system, the switch output module is respectively connected to the circuit breaker operation circuit of each interval connected to the small power supply 1 to the small power supply n of the upper substation and the upper longitudinal remote transmission device, the switch output module sends a tripping node to complete the removal of each small power supply circuit in the upper substation, and the switch output module sends a joint-cutting command to each small power supply circuit of the lower substation through the upper longitudinal remote transmission device;

[0017] The upper-level longitudinal remote transmission device includes a switch input module, a protection channel module and a power supply module. The power supply module supplies power to the switch input module and the protection channel module respectively. The input end of the switch input module receives the inter-cut node signal sent by the inter-cut intelligent terminal. The output end of the switch input module is connected to the protection channel module. The protection channel module sends the received inter-cut node signal to the lower-level longitudinal remote transmission device.

[0018] The lower-level longitudinal remote transmission device includes a protection channel module, a switch output module, and a power supply module. The power supply module supplies power to the protection channel module and the switch output module respectively. The input end of the protection channel module receives the disconnection node signal sent by the upper-level longitudinal remote transmission device. The output end of the protection channel module is connected to the switch output module. The switch output module is respectively connected to the circuit breaker operating circuits of each interval of the lower-level substation accessing small power supply 1 to small power supply n. The switch output module sends a tripping node to complete the disconnection of each small power supply circuit in the lower-level substation.

[0019] It can be seen from the above technical solution that the beneficial effects of the present invention are: First, the present invention relies on the optical fiber communication within the station and the optical fiber communication of the longitudinal remote transmission device between stations to accurately cut off the small power sources of various levels of multiple substations in the regional power grid that affect the automatic switching of the standby power supply, avoid the wrong load shedding caused by the conventional automatic switching of the standby power supply, and ensure the reliable power supply of important loads; second, the present invention simplifies the secondary circuit within the station, and uses the tripping command of the main power supply switch and the joint switching command of the standby power supply device as the input for the joint switching of the small power supply, which not only meets the requirements of the regulations, but also improves the efficiency of design and construction, and has a good application prospect in the field of new energy control and protection technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of a regional power grid network architecture according to a first embodiment of the present invention;

[0021] Figure 2 This is a schematic diagram of the regional power grid and small power supply joint switching system architecture according to the first embodiment of the present invention;

[0022] Figure 3 It is the system information flow and logic diagram of the present invention;

[0023] Figure 4 It is a flow chart of the control method of the present invention. DETAILED DESCRIPTION

[0024] like Figure 1 、 2 As shown in FIG. 3 , a system for switching a small power source of a regional power grid in conjunction with a backup automatic switching device comprises:

[0025] The intelligent terminal for joint cutting is used to receive the GOOSE tripping commands from the main power supply switch intelligent terminal and the standby automatic transfer device, and issue a tripping node to complete the disconnection of each small power circuit in the upper-level substation; the intelligent terminal for joint cutting is installed at the upper-level substation end; the standby automatic transfer device is a conventional standby automatic transfer device, which is suitable for incoming lines or main transformer standby transfer with one power supply in operation and the other power supply as a standby; it is also suitable for incoming lines or main transformer standby transfer with two power supplies in operation, segmented tripping, and voltage loss on one busbar.

[0026] The upper-level longitudinal remote transmission device is used to receive the inter-cut node signal sent by the inter-cut intelligent terminal and send the received inter-cut node signal to the lower-level longitudinal remote transmission device; the upper-level longitudinal remote transmission device is installed at the upper-level substation end;

[0027] The lower level longitudinal remote transmission device is used to receive the disconnection node signal sent by the upper level longitudinal remote transmission device and send a tripping node to complete the disconnection of each small power supply circuit in the lower level substation; the lower level longitudinal remote transmission device is installed at the lower level substation end;

[0028] The intelligent terminal for joint cutting sends a joint cutting node signal to the upper-level longitudinal remote transmission device. The upper-level longitudinal remote transmission device and the lower-level longitudinal remote transmission device are directly connected through a dedicated protection channel optical cable or multiplexed connection of communication equipment. The intelligent terminal for joint cutting communicates with the substation monitoring system in two directions.

[0029] The joint-cutting intelligent terminal includes an optical input module, a switch input module, a logic judgment module, a switch output module, a communication module, and a power module; the power module supplies power to the optical input module, the switch input module, the logic judgment module, the switch output module, and the communication module respectively. The optical input module receives a GOOSE tripping command from the main power supply switch intelligent terminal or the backup automatic transfer device via a direct optical cable connection; the switch input module receives a tripping command from the main power supply switch intelligent terminal or the backup automatic transfer device via a switch node signal; the output ends of the optical input module and the switch input module are both connected to the input end of the logic judgment module, and the output end of the logic judgment module is respectively connected to the input ends of the switch output module and the communication module. The communication module communicates bidirectionally with the substation monitoring system; the switch output module is respectively connected to the circuit breaker operating circuits of each interval connected to small power sources 1 to small power sources n in the upper-level substation and the upper-level longitudinal remote transmission device. The switch output module issues a tripping node to complete the disconnection of each small power supply circuit in the upper-level substation, and the switch output module issues a joint-cutting command to each small power supply circuit of the lower-level substation via the upper-level longitudinal remote transmission device.

[0030] The upper-level longitudinal remote transmission device includes a switch input module, a protection channel module and a power supply module. The power supply module supplies power to the switch input module and the protection channel module respectively. The input end of the switch input module receives the inter-cut node signal sent by the inter-cut intelligent terminal. The output end of the switch input module is connected to the protection channel module. The protection channel module sends the received inter-cut node signal to the lower-level longitudinal remote transmission device.

[0031] The lower-level longitudinal remote transmission device includes a protection channel module, a switch output module, and a power supply module. The power supply module supplies power to the protection channel module and the switch output module respectively. The input end of the protection channel module receives the disconnection node signal sent by the upper-level longitudinal remote transmission device. The output end of the protection channel module is connected to the switch output module. The switch output module is respectively connected to the circuit breaker operating circuits of each interval of the lower-level substation accessing small power supply 1 to small power supply n. The switch output module sends a tripping node to complete the disconnection of each small power supply circuit in the lower-level substation.

[0032] like Figure 4 As shown, the method includes the following steps in order:

[0033] (1) If the external power grid fault causes the main power switch of the upper substation to trip, the various protection devices will send protection action commands to the intelligent terminal of the main power switch; the intelligent terminal of the main power switch will transmit its own TJQ, TJR, TJF trip GOOSE signals to the joint switching intelligent terminal through the optical cable;

[0034] (2) If the external power grid failure causes the main power supply of the upper substation to lose power, and the standby automatic switching device meets the corresponding starting conditions, the standby automatic switching device sends a GOOSE signal for joint switching to the joint switching intelligent terminal through the optical cable;

[0035] (3) The intelligent terminal for joint switching receives the GOOSE signals of step (1) and step (2), and after logical judgment, sends the tripping node to the upper-level substation to access the circuit breaker operation circuit of each interval of small power source 1 to small power source n and the upper-level longitudinal remote transmission device;

[0036] (4) The upper substation is connected to the circuit breaker operation circuits of each interval of small power source 1 to small power source n to complete the disconnection of each small power source circuit in the upper substation;

[0037] (5) The upper longitudinal remote transmission device sends the disconnection node signal to the lower longitudinal remote transmission device through the protection channel directly connected by optical cable or the multiplexing communication connection equipment. The lower longitudinal remote transmission device sends the tripping node to the lower substation to access the circuit breaker operation circuits of each interval of small power supply 1 to small power supply n, and cut off the small power supply circuits in the lower substation.

[0038] With the construction of new power systems, a high proportion of new energy sources are connected to the power grid, which puts higher demands on the absorption, safety and stability capabilities of traditional power grids. The access of small power sources with high penetration rate has brought new challenges to the normal operation of traditional safety equipment of the power grid, such as automatic backup and reclosing devices. For example, in order to avoid asynchronous closing after the automatic backup device is actuated, it is necessary to accurately and efficiently cut off the small power sources connected to the grid at this level and the lower level power grid. In view of the deficiency of unnecessary load power loss caused by the overall connection of conventional automatic backup devices to the lower level substations connected to small power sources, the present invention provides a system and control method for connecting and cutting small power sources of the regional power grid in conjunction with the automatic backup device, thereby improving the power supply reliability of the regional power grid.

[0039] In order to illustrate the technical solution of the present invention, specific embodiments are provided below. Example 1

[0040] like Figure 1 As shown, small power sources are connected to the system at multiple voltage levels. Currently, the 220kV substation B0 has only one main transformer, and the 220kV busbar serves as the system power source. The 110kV busbar utilizes a single busbar with sectionalized wiring. To ensure reliable power supply to the 110kV downstream grid, the 110kV busbar at B0 is connected to a single 110kV power line Y0 as a backup power source. The 110kV line Y1 at B0 serves as a centralized renewable energy transmission line, while the remaining 110kV lines are load lines. Small power sources are also connected to the medium and low voltage sides of the downstream 110kV substations Y0A and Y0B. A single renewable energy line is connected to the 10kV line at B0, with the grid-connecting switch D5. The remaining lines are load lines.

[0041] like Figure 1 As shown, during normal operation, the 220kV side switch D0 of the main transformer in B0 substation, the 110kV side switch D1 of the main transformer, and the 110kV busbar section switch D2 are all in the closed position, and the 110kV backup power supply Y0 switch D3 is in the open position.

[0042] A backup automatic switching device is set for switches D1 and D3. When the medium and high voltage sides of the main transformer of B0 substation, which serves as the main power supply, lose power, the conventional backup automatic switching device and the joint disconnection system will trip switch D1, and after joint disconnection of all small power lines Y0A, Y0B, Y1, and Y2 connected to B0 substation, switch D3 will be closed after a delay. Considering that both 110kV substations Y0A and Y0B are connected to important loads, the conventional backup automatic switching method will cause the entire 110kV substation Y0A and Y0B to lose power, reducing the reliability of the regional power grid. For example, Figure 1 The present invention is configured in the regional grid shown, and instead of directly disconnecting the 110kV substations Y0A and Y0B, all small power sources connected to the upper substation B0 and the lower substations Y0A and Y0B are accurately disconnected to ensure reliable power supply to important loads.

[0043] like Figure 2 As shown, the upper-level substation B0 is equipped with a conventional standby automatic switching device, an intelligent terminal for interlocking, an upper-level remote transmission device, and a lower-level remote transmission device. The conventional standby automatic switching device is installed for switches D1 and D3, and acts as an incoming line standby automatic switching device between the 110kV incoming line of the B0 substation's main transformer and the 110kV backup power source Y0. The optical input module of the interlocking intelligent terminal is connected via optical fiber to the conventional standby automatic switching device, the intelligent terminal for the 220kV incoming line switch of the B0 substation's main transformer, and the intelligent terminal for the 110kV incoming line switch of the B0 substation's main transformer. The switch output module of the interlocking intelligent terminal is connected via cables to the upper-level remote transmission device, the operating circuit of the grid-connected switch D4 of the 110kV new power source line Y1, and the operating circuit of the grid-connected switch D5 of the 10kV new power source line Y2. The upper longitudinal remote transmission device of the B0 substation receives the inter-cut node signal sent by the intelligent terminal for inter-cutting through the switch input module, and is connected to the lower longitudinal remote transmission device at the lower Y0A substation and Y0B substation through the protection channel module directly through the dedicated protection channel optical cable or through the multiplexing method of communication equipment.

[0044] A lower-level pilot remote transmission device is installed at lower-level substation Y0A. The protection channel module receives the tripping signal from the upper-level pilot remote transmission device. The switch output module then connects the device to the operating circuits of the 35kV new power line Y0A1 grid-connected switch DA1 and the 10kV new power line Y0A2 grid-connected switch DA2 via cables.

[0045] Similarly, a lower-level pilot remote transmission device is installed at lower-level substation Y0B. The protection channel module in the lower-level pilot remote transmission device receives the tripping signal from the upper-level pilot remote transmission device. The switch output module then connects the device to the operating circuits of the 35kV new power line Y0B1 grid-connected switch DB1 and the 10kV new power line Y0B2 grid-connected switch DB2 via cables.

[0046] like Figure 3 As shown in the figure, the main transformer power protection action, non-power protection action, high-voltage side failure joint trip, 220kV bus differential action, etc. are connected to the main power supply switch D0 intelligent terminal. The D0 intelligent terminal sends the TJQ, TJR, and TJF signals corresponding to the relevant protection actions to the upper-level BO substation joint trip intelligent terminal.

[0047] The main transformer power protection action, non-power protection action, high-voltage side failure joint trip, 110kV bus differential action, etc. are connected to the main power supply switch D1 intelligent terminal. The D1 intelligent terminal sends the TJQ, TJR, and TJF signals corresponding to the relevant protection actions to the upper-level BO substation joint switching intelligent terminal.

[0048] If the standby automatic start-up conditions are met (AND logic), such as no busbar pressure, no current on the incoming line of the D1 switch, open position of the D3 switch, pressure on the line side of the D3 switch, and charging is completed, the standby automatic start-up device of the upper-level BO substation sends a joint switching signal to the upper-level BO substation joint switching intelligent terminal.

[0049] The upper-level BO substation joint-cutting intelligent terminal receives the D0 intelligent terminal, the TJQ, TJR, TJF signals of the D0 intelligent terminal, and the joint-cutting signal of the standby automatic transfer device, and sends a tripping node to the upper-level BO substation through OR logic to complete the cutting of each small power supply circuit, and sends a joint-cutting command to the upper-level longitudinal remote transmission device.

[0050] In summary, the present invention can rely on the fiber optic communication within the station and the fiber optic communication of the longitudinal remote transmission device between stations to accurately cut off the small power sources of various levels of multiple substations in the regional power grid that affect the automatic switching of the backup power supply, avoid the wrong load shedding caused by the conventional automatic switching of the backup power supply, and ensure the uninterrupted power supply of important loads; at the same time, it simplifies the secondary circuit within the station, and uses the tripping command of the main power supply switch and the joint cutting command of the backup power supply device as the input for the joint cutting of the small power source, which not only meets the requirements of the regulations but also improves the efficiency of design and construction. It has a good application prospect in the field of new energy control and protection technology.

Claims

1. A control method for connecting and disconnecting a small power source of a regional power grid in cooperation with a standby automatic switching device, characterized in that: The method comprises the following steps in order: (1) If the external power grid fault causes the main power switch of the upper substation to trip, all kinds of protection devices will send protection action commands to the intelligent terminal of the main power switch; the intelligent terminal of the main power switch will transmit its own TJQ, TJR, TJF tripping GOOSE signals to the joint switching intelligent terminal through the optical cable; (2) If the external power grid fails and the main power supply of the upper substation is lost, and the standby automatic switching device meets the corresponding startup conditions, the standby automatic switching device sends a GOOSE signal for joint switching to the joint switching intelligent terminal through the optical cable; (3) The intelligent terminal for joint switching receives the GOOSE signals of step (1) and step (2), and after logical judgment, sends the tripping node to the upper-level substation to access the circuit breaker operation circuits of each interval of small power source 1 to small power source n and the upper-level longitudinal remote transmission device; (4) The upper-level substation is connected to the circuit breaker operation circuits of each interval of small power source 1 to small power source n to complete the disconnection of each small power source circuit in the upper-level substation; (5) The upper longitudinal remote transmission device sends the disconnection node signal to the lower longitudinal remote transmission device through the protection channel directly connected by optical cable or the multiplexed communication connection device. The lower longitudinal remote transmission device sends the trip node to the lower substation to access the circuit breaker operation circuits of each interval of small power source 1 to small power source n, thereby cutting off the circuits of each small power source in the lower substation; The joint-cutting intelligent terminal is used to receive the GOOSE tripping command of the main power supply switch intelligent terminal and the standby automatic switching device, and issue a tripping node to complete the removal of each small power supply circuit in the upper-level substation; the joint-cutting intelligent terminal is installed at the upper-level substation end; The upper longitudinal remote transmission device is used to receive the inter-cut node signal sent by the inter-cutting intelligent terminal, and send the received inter-cut node signal to the lower longitudinal remote transmission device; the upper longitudinal remote transmission device is installed at the upper substation end; The lower level longitudinal remote transmission device is used to receive the cut-off node signal sent by the upper level longitudinal remote transmission device, and send a trip node to complete the cut-off of each small power supply circuit in the lower level substation; the lower level longitudinal remote transmission device is installed at the lower level substation end; The intelligent terminal for joint cutting sends a joint cutting node signal to the upper-level longitudinal remote transmission device. The upper-level longitudinal remote transmission device and the lower-level longitudinal remote transmission device are directly connected through a dedicated protection channel optical cable or multiplexed connection of communication equipment. The intelligent terminal for joint cutting communicates bidirectionally with the substation monitoring system. The joint-cutting intelligent terminal includes an optical input module, a switch input module, a logic judgment module, a switch output module, a communication module and a power module; the power module supplies power to the optical input module, the switch input module, the logic judgment module, the switch output module and the communication module respectively; the optical input module receives the GOOSE tripping command issued by the main power switch intelligent terminal and the standby automatic transfer device by means of a direct optical cable connection; the switch input module receives the tripping command of the main power switch intelligent terminal or the standby automatic transfer device by means of a switch node signal; the output ends of the optical input module and the switch input module are both connected to the input end of the logic judgment module, the output end of the logic judgment module is respectively connected to the input end of the switch output module and the communication module, the communication module communicates bidirectionally with the substation monitoring system, the switch output module is respectively connected to the circuit breaker operation circuit of each interval of the upper substation accessing small power 1 to small power n and the upper longitudinal remote transmission device, the switch output module sends a tripping node to complete the removal of each small power circuit in the upper substation, and the switch output module sends a joint-cutting command to each small power circuit of the lower substation through the upper longitudinal remote transmission device; The upper-level longitudinal remote transmission device includes a switch input module, a protection channel module and a power module. The power module supplies power to the switch input module and the protection channel module respectively. The input end of the switch input module receives the inter-cut node signal sent by the inter-cutting intelligent terminal. The output end of the switch input module is connected to the protection channel module. The protection channel module sends the received inter-cut node signal to the lower-level longitudinal remote transmission device. The lower-level longitudinal remote transmission device includes a protection channel module, a switch output module, and a power supply module. The power supply module supplies power to the protection channel module and the switch output module respectively. The input end of the protection channel module receives the joint cutting node signal sent by the upper-level longitudinal remote transmission device, and the output end of the protection channel module is connected to the switch output module. The switch output module is respectively connected to the circuit breaker operation circuits of each interval of the lower-level substation accessing small power supply 1 to small power supply n. The switch output module sends a tripping node to complete the cutting of each small power supply circuit in the lower-level substation.

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