A distribution network primary and secondary fusion complete ring network box bus protection method and device

Abstract

The application discloses a kind of network primary-secondary fusion complete ring net box bus protection method and device.Method includes determining the non-end breaker on the main line or large branch line in ring net box as sectionalizing switch;If the distribution terminal trigger node fault signal corresponding to sectionalizing switch, and in signal collection time, not received the node fault signal of any other loop distribution terminal on ring net box bus, send command outlet trip, complete fault removal, while sending trip signal to distribution terminal in other interval unit topologically adjacent to this interval unit;After receiving trip signal, distribution terminal in other interval unit topologically adjacent to this interval unit sends command to trip the breaker of respective interval unit, and completes fault isolation.The application scheme can timely cut off the fault part under the condition that 10kV primary-secondary fusion complete ring net box bus fails, avoid fault diffusion and escalation, and protect the operation of entire 10kV distribution network system.

Description

Technical Field

[0001] This invention relates to the field of integrated primary and secondary distribution network ring network boxes, and particularly to a method and device for protecting the busbar of an integrated primary and secondary distribution network ring network box. Background Technology

[0002] Distribution automation is a crucial component of power system automation, utilizing modern communication and computer technologies to monitor, manage, and control the distribution network in real time. The integrated primary and secondary ring main unit (RMU) is an important piece of equipment that integrates primary equipment (such as circuit breakers and disconnectors) and secondary equipment (such as monitoring and protection systems) into a single enclosure, enabling the protection and control of the power network. Furthermore, the integrated primary and secondary ring main unit can communicate with remote servers via network communication interfaces, achieving remote monitoring and automated control.

[0003] Patent CN201810386606.1 proposes a maintenance method for distributed protection in a smart substation, specifically for the maintenance of main grid busbar protection, but does not address the busbar protection functions and maintenance methods for distribution networks. Patent CN201910280740.8 proposes a protection modification system and method based on power system backup power, modifying busbar protection within a substation to ensure that maintenance of one busbar does not affect the operation of another, but does not conduct related research on distribution network busbar protection. Patent CN202320559918.4 proposes a distribution network busbar protection device, adopting a primary equipment structure design to optimize the distribution network busbar operating environment, but does not address how to quickly locate and isolate faults when they occur.

[0004] Based on this, there is still considerable room for improvement in the existing technology regarding busbar protection for integrated primary and secondary ring network boxes in distribution networks. Summary of the Invention

[0005] To address the technical problem of failure to promptly disconnect the busbar of a combined primary and secondary distribution network ring network box when a fault occurs, this invention provides a method and device for protecting the busbar of a combined primary and secondary distribution network ring network box.

[0006] The technical solution of this invention is implemented as follows:

[0007] This invention provides a method for protecting the busbar of a distribution network integrated primary and secondary ring main unit, applied to such a unit. The integrated ring main unit includes a power supply-side incoming circuit breaker, multiple feeder circuit breakers, a ring main unit busbar, and multiple distribution terminals. The inflow current into the ring main unit flows through the power supply-side incoming circuit breaker into the ring main unit busbar, then from the busbar into the multiple feeder circuit breakers before flowing out. Each circuit breaker is connected to a corresponding distribution terminal, and each distribution terminal is used for data acquisition and control of the connected circuit breaker. Each circuit breaker and its corresponding distribution terminal form a bay unit. The circuit breakers can communicate with each other; the method includes: identifying the non-terminal circuit breakers on the main line or large branch line in the integrated primary and secondary ring network box of the distribution network as sectionalizing switches; if the distribution terminal corresponding to the sectionalizing switch detects the fault trigger node fault signal, and within the signal collection time does not receive any node fault signal from the distribution terminal of any other interval circuit on the ring network box bus, it issues a command to control the outlet of this interval unit to trip, complete the fault clearing, and at the same time sends a trip signal to the distribution terminals in other interval units that are topologically adjacent to this interval unit; after receiving the trip signal, the distribution terminals in other interval units that are topologically adjacent to this interval unit issue a command to trip the circuit breakers of their respective interval units, complete the fault isolation.

[0008] In one embodiment, each distribution terminal acquires measurement data within its own bay unit, the measurement data including voltage, current, and power; it determines whether the preset CT disconnection blocking bus protection conditions are met based on the measurement data; if the preset CT disconnection blocking bus protection conditions are met, CT disconnection blocking bus protection is performed; the CT disconnection blocking bus protection means that the distribution terminals of each bay unit no longer perform logical analysis and event processing for the bus protection function.

[0009] In one embodiment, the preset CT disconnection blocking bus protection condition is: the maximum phase current is greater than 0.02In; and the maximum phase current is greater than 4 times any phase current.

[0010] In one embodiment, when it is determined that the preset CT disconnection blocking bus protection conditions are met, CT disconnection blocking bus protection is performed, which includes: after a preset time delay, triggering a CT disconnection blocking bus protection command to perform CT disconnection blocking bus protection.

[0011] In one embodiment, the CT disconnection blocking busbar protection is performed when the GOOSE communication of the power distribution terminal of each of the interval units is abnormal.

[0012] This invention also provides a distribution network primary and secondary integrated ring main unit bus protection device. The device includes a power supply side incoming circuit breaker, multiple feeder circuit breakers, a ring main unit bus, and multiple distribution terminals. The inflow current into the distribution network primary and secondary integrated ring main unit flows through the power supply side incoming circuit breaker into the ring main unit bus, then from the ring main unit bus into the multiple feeder circuit breakers before flowing out. Each circuit breaker is connected to a corresponding distribution terminal, and each distribution terminal is used for data acquisition and control of the connected circuit breaker. Each circuit breaker and its corresponding connected distribution terminal form a bay unit, and the distribution terminals can communicate with each other. The non-terminal circuit breakers on the main lines or major branch lines of the integrated primary and secondary distribution network ring network box are sectionalizing switches. The distribution terminal corresponding to the sectionalizing switch is used to issue a command to control the tripping of the output of this bay unit after detecting the fault triggering node fault signal, and within the signal collection time, without receiving the node fault signal of any other bay circuit distribution terminal on the ring network box bus, to complete the fault clearing, and at the same time send a tripping signal to the distribution terminals in other bay units topologically adjacent to this bay unit. The distribution terminals in other bay units topologically adjacent to this bay unit are used to issue a command to trip the circuit breaker of their respective bay units after receiving the tripping signal, to complete the fault isolation.

[0013] In one embodiment, each of the power distribution terminals is further configured to acquire measurement data within its own bay unit, the measurement data including voltage, current, and power; determine whether the preset CT disconnection blocking bus protection conditions are met based on the measurement data; and perform CT disconnection blocking bus protection if the preset CT disconnection blocking bus protection conditions are met; wherein the CT disconnection blocking bus protection means that the power distribution terminals of each bay unit no longer perform logical analysis and event processing for the bus protection function.

[0014] In one embodiment, the preset CT disconnection blocking bus protection condition is: the maximum phase current is greater than 0.02In; and the maximum phase current is greater than 4 times any phase current.

[0015] In one embodiment, each of the power distribution terminals is further specifically used to, after a preset delay, trigger a CT disconnection blocking bus protection command to perform CT disconnection blocking bus protection when it is determined that the preset CT disconnection blocking bus protection conditions are met.

[0016] In one embodiment, the power distribution terminal of each of the interval units is also used to perform CT disconnection blocking bus protection in the event of GOOSE communication failure.

[0017] The solution in this embodiment has the following beneficial effects:

[0018] This embodiment of the solution can, in the event of a fault in the 10 kV integrated primary and secondary ring network busbar, use the sampling and GOOSE information collected in real time by the distribution terminal from each bay unit, and after logical analysis, promptly disconnect the faulty part to prevent the fault from spreading and escalating, prevent the fault range from expanding, and prevent it from affecting the upstream power grid equipment, thus protecting the operation of the entire 10 kV distribution network feeder. Attached Figure Description

[0019] Figure 1 This is a flowchart illustrating the method for protecting the integrated primary and secondary ring network busbars of the distribution network according to an embodiment of the present invention.

[0020] Figure 2 This is a schematic diagram of the integrated ring network box for primary and secondary distribution networks according to an embodiment of the present invention;

[0021] Figure 3 This is a physical schematic diagram of the integrated primary and secondary distribution network ring network box according to an embodiment of the present invention;

[0022] Figure 4 This is a schematic diagram of the bus fault clearing logic according to an embodiment of the present invention;

[0023] Figure 5 This is a schematic diagram of bus fault isolation logic in an embodiment of the present invention. Detailed Implementation

[0024] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0025] This invention provides a method for protecting the busbar of a distribution network integrated primary and secondary ring main unit, applied to such a unit. The integrated ring main unit includes a power supply-side incoming circuit breaker, multiple feeder circuit breakers, a ring main unit busbar, and multiple distribution terminals. The inflow current into the ring main unit flows through the power supply-side incoming circuit breaker into the ring main unit busbar, then from the busbar into the multiple feeder circuit breakers before flowing out. Each circuit breaker is connected to a corresponding distribution terminal, and each distribution terminal is used for data acquisition and control of the connected circuit breaker. Each circuit breaker and its corresponding distribution terminal form a bay unit, and the distribution terminals can communicate with each other. Figure 1 As shown, the method includes:

[0026] Step 101: Determine that the non-terminal circuit breaker on the main line or major branch line in the integrated primary and secondary ring network box of the distribution network is a sectionalizing switch;

[0027] Step 102: If the distribution terminal corresponding to the sectionalizing switch detects the fault trigger node fault signal, and does not receive any node fault signal from the distribution terminal of any other bay circuit on the ring network box bus within the signal collection time, it issues a command to control the outlet of this bay unit to trip, complete the fault clearing, and at the same time sends a trip signal to the distribution terminal in other bay units that are topologically adjacent to this bay unit.

[0028] Step 103: After receiving the trip signal, the power distribution terminal in other bay units that are topologically adjacent to this bay unit issues a command to trip the circuit breaker of their respective bay units to complete the fault isolation.

[0029] This embodiment primarily focuses on busbar protection for ring main units based on distributed feeder automation. Its main function is to promptly disconnect the faulty section in the event of a fault in the busbar of a 10kV integrated primary and secondary ring main unit, preventing the fault from spreading and escalating, and protecting the operation of the entire 10kV distribution network system. Distributed feeder automation refers to the automatic fault location, isolation, and restoration of power to non-faulty areas achieved through communication between the distribution terminals (protection and control devices in each bay unit of the ring main unit). The processing and results can be reported to the distribution automation master station.

[0030] A primary and secondary integrated ring main unit is a type of equipment in a power distribution system, mainly composed of incoming and outgoing cabinets, as well as corresponding protection and control devices. It integrates primary and secondary side power distribution, protection, and control equipment into a single enclosure. For example... Figure 2 and Figure 3 As shown, in the ring main unit, 301, 303, 305, 307, 309, and 311 are bay circuit breakers. Among them, 301 is the incoming circuit breaker on the power supply side, and 303, 305, 307, 309, and 311 are feeder circuit breakers. The copper plates connecting these circuit breakers form the ring main unit busbar. The current output from the substation flows into the ring main unit from 301, then through the busbar to the feeder circuit breakers 303, 305, 307, 309, and 311, and finally to the downstream user load. Unlike traditional ring main units, each bay circuit in this integrated primary and secondary ring main unit is equipped with a distribution terminal (protection and control device). The distribution terminal can realize real-time acquisition and monitoring of data such as voltage, current, and switch information for this circuit. In the event of a short circuit or other fault, the secondary protection device of this circuit enables the circuit breaker to selectively, rapidly, reliably, and sensitively isolate the fault. The device can not only realize the line protection function of this bay unit, but also realize the distributed feeder automation function mentioned above based on the mutual communication of each power distribution terminal.

[0031] The specific action logic of this embodiment is as follows:

[0032] Busbar Protection Logic: Within the 10kV distribution network integrated primary and secondary ring network box, each bay unit is equipped with a distributed distribution terminal, which can monitor the measurement data and protection action event signals of its bay unit in real time (measurement data includes electrical quantities such as voltage, current, and power; protection action event signals are the relevant alarms and action information issued by the protection device after detecting fault current and voltage data during a grid fault). Based on the 61850 GOOSE transmission, these protection action event signals can be sent to the distribution terminals (protection and control devices) of other bay units topologically adjacent to this bay unit (topologically adjacent refers to electrical circuits connected by primary electrical structures). When a sectionalizing switch (a non-terminal switch on the main line or a large branch line, such as...) is activated... Figure 2 As shown in Figures 301 and 303 (which can be identified as sectionalizing switches), the distribution terminal (protection and control device) triggers a "node fault (the switch triggers a node fault upon detecting a short-circuit overcurrent or zero-sequence overcurrent)" signal after detecting a fault. During the signal collection period, the distribution terminal (protection and control device) of this bay unit communicates with the protection and control devices of other bay units topologically adjacent to this bay unit. After not receiving a "node fault" signal from any other bay unit circuit distribution terminal (protection and control device) on the ring mains bus, the fault handling unit of the distribution terminal (protection and control device) issues a command to trip, opening the switch of this bay unit to achieve fault isolation. The logic is as follows: Figure 4 Simultaneously, a GOOSE trip signal is sent to the protection and control devices of other bay units adjacent to this bay unit. Upon receiving the GOOSE trip signal, the power distribution terminals (protection and control devices) of other bay units will issue commands to trip the switches of their respective bay units, achieving fault isolation. See the logic below. Figure 5 .

[0033] For example: with Figure 2 For example: When switch 301 is the power supply incoming switch, switches 303, 305, 307, 309, and 311 are all feeder switches, and switches 301 and 303 are sectionalizing switches (non-terminal switches on the main line or large branch lines). When a fault occurs on the busbar of this ring main unit, switch 301 will detect an overcurrent fault signal, but switches 303, 305, 307, 309, and 311 will not detect an overcurrent fault signal. Switch 301 communicates with the adjacent switches in this bay unit topology but does not receive the corresponding fault signal. Therefore, the protection device of bay unit 301 trips the bay switch, achieving fault isolation. At the same time, a GOOSE trip signal is sent to switches 303, 305, 307, 309, and 311, tripping switches 303, 305, 307, 309, and 311, achieving fault isolation.

[0034] Protection interlocking logic: Busbar protection is interlocked when any CT disconnects in any bay unit of the ring main unit (the busbar protection function of the fault handling unit in each bay unit's distribution terminal is no longer subject to logic analysis and event handling). Corresponding busbar protection is interlocked when the GOOSE communication of each bay distribution terminal is abnormal.

[0035] CT disconnection logic:

[0036] 1. Maximum phase current greater than 0.02In;

[0037] 2. The maximum phase current is greater than 4 times the current of any phase.

[0038] If the above two conditions are met, a "CT disconnection alarm" will be reported after a 10-second delay, and an alarm signal will be issued by the device.

[0039] The solution in this embodiment has the following beneficial effects:

[0040] Distributed control: Compared with traditional centralized bus protection, bus protection based on distributed feeder automation adopts a distributed control strategy, distributing protection functions to the distribution terminals (protection and control devices) of each bay unit. Data sharing and collaborative operation among the distribution terminals (protection and control devices) of each bay unit are achieved through fiber optic communication technology. This makes the bus protection more flexible and scalable.

[0041] Rapid Response: Distributed feeder automation technology can monitor the operating status of the power grid in real time and achieve rapid response to bus faults through intelligent control strategies. Once a bus fault is detected, the system can quickly locate the fault point and isolate the fault area, thereby preventing the fault from escalating and causing further damage to the power grid.

[0042] High Reliability: Busbar protection based on distributed feeder automation employs advanced communication technology and intelligent control strategies, ensuring the accuracy and reliability of protection actions. Furthermore, through distributed control strategies, the system can achieve multiple detections and verifications of busbar faults, further enhancing protection reliability.

[0043] This invention also provides a distribution network primary and secondary integrated ring network box busbar protection device. The device includes a power supply side incoming circuit breaker, multiple feeder circuit breakers, a ring network box busbar, and multiple distribution terminals. The inflow current into the distribution network primary and secondary integrated ring network box flows into the ring network box busbar via the power supply side incoming circuit breaker, then flows from the ring network box busbar into the multiple feeder circuit breakers before flowing out. Each circuit breaker is connected to a corresponding distribution terminal, and each distribution terminal is used for data acquisition and control of the connected circuit breaker. Each circuit breaker and its corresponding connected distribution terminal form a bay unit, and the distribution terminals can communicate with each other. The non-terminal circuit breakers on the main line or large branch line in the distribution network primary and secondary integrated ring network box are sectionalizing switches.

[0044] The distribution terminal corresponding to the sectionalizing switch is used to issue a command to control the outlet of this bay unit to trip after detecting the fault signal of the fault triggering node, and within the signal collection time, without receiving the node fault signal of any other bay circuit distribution terminal on the ring network box bus, to complete the fault clearing, and at the same time send a trip signal to the distribution terminal in other bay units that are topologically adjacent to this bay unit.

[0045] The power distribution terminals in other bays topologically adjacent to this bay unit are used to issue commands to trip the circuit breakers of their respective bay units after receiving the trip signal, thereby completing fault isolation.

[0046] The power distribution terminal in this embodiment has a built-in fault handling unit. The fault handling unit is a functional module that can effectively protect the busbar of the integrated primary and secondary ring network box of the 10 kV distribution network. When the busbar fails, it can quickly isolate the fault, reduce power grid losses, and restore normal power supply to the non-faulty areas.

[0047] Specifically, in one embodiment, each of the power distribution terminals is further configured to acquire measurement data within its own bay unit, the measurement data including voltage, current, and power; determine whether the preset CT disconnection blocking bus protection conditions are met based on the measurement data; and perform CT disconnection blocking bus protection if the preset CT disconnection blocking bus protection conditions are met; the CT disconnection blocking bus protection means that the power distribution terminals of each bay unit no longer perform logical analysis and event processing for the bus protection function.

[0048] Here, the preset CT disconnection blocking bus protection condition is: the maximum phase current is greater than 0.02In; and / or, the maximum phase current is greater than 4 times any phase current.

[0049] In addition, each of the aforementioned power distribution terminals is specifically used to, after a preset delay, trigger a CT disconnection blocking bus protection command to perform CT disconnection blocking bus protection when it is determined that the preset CT disconnection blocking bus protection conditions are met.

[0050] The power distribution terminal of each of the aforementioned bay units is also used to perform CT disconnection blocking bus protection in the event of GOOSE communication failure.

[0051] The device in this embodiment is mainly used to promptly disconnect the faulty part in the event of a fault in the 10 kV integrated primary and secondary ring network busbar. This is achieved by collecting real-time sampling and GOOSE information from each bay through terminal equipment, followed by logical analysis. This prevents the fault from spreading and escalating, thus preventing the fault range from expanding and affecting the upstream power grid equipment and protecting the operation of the entire 10 kV distribution network feeder.

[0052] The solution in this embodiment has the following beneficial effects:

[0053] (1) Simplified secondary wiring: Distributed busbar protection technology distributes the function of a traditional bus differential protection device to multiple bay units (eL), so that each eL is only connected to the corresponding current transformer (CT). This design greatly simplifies the secondary wiring of the protection and reduces the complexity of field operation and maintenance.

[0054] (2) Improved reliability and speed: Based on the novel CT saturation detection method, distributed bus protection technology provides comprehensive current differential protection functions. The local criteria of the bay unit (BU) ensure the reliability of distributed bus protection, ensuring that the fault can be quickly and accurately cleared in the event of a bus fault.

[0055] (3) Reduced footprint and cable consumption: Distributed bus protection technology enables data sharing between different bay units through communication technology, eliminating the need for dedicated protection panels.

[0056] (4) Enhanced Adaptability: Distributed bus protection technology provides a PC-based graphical input function for network topology, facilitating user operation and ensuring the selectivity of bus protection. This design gives the protection a strong adaptive capability, enabling it to automatically adjust the protection strategy according to changes in the power grid topology.

[0057] (5) Achieving millisecond-level self-healing: In the distributed intelligent feeder automation mode, millisecond-level self-healing of the power grid with multiple backup protections can be achieved. This is of great significance for improving the power supply reliability and stability of the power grid.

[0058] The apparatus provided in this embodiment and the method embodiment described above belong to the same concept. For details of its implementation, please refer to the method embodiment, which will not be repeated here.

[0059] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0060] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A method for network distribution and secondary fusion complete ring network box bus protection, characterized in that, The application is applied to a distribution network primary and secondary fusion integrated ring network box, which comprises a power supply side incoming line circuit breaker, a plurality of feeder circuit breakers, a ring network box bus and a plurality of distribution terminals; the inflow current of the distribution network primary and secondary fusion integrated ring network box flows into the ring network box bus through the power supply side incoming line circuit breaker, and then flows into the plurality of feeder circuit breakers and then flows out; each circuit breaker is connected with one distribution terminal respectively, and each distribution terminal is used for collecting and controlling the connected circuit breaker; Each circuit breaker and the corresponding connected distribution terminal form an interval unit, and the distribution terminals can communicate with each other; the method comprises the following steps: determining a non-terminal circuit breaker on a main line or a large branch line in the distribution network primary and secondary fusion integrated ring network box as a sectionalizing switch; if the distribution terminal corresponding to the sectionalizing switch detects a fault trigger node fault signal, and no node fault signal of any other interval loop distribution terminal on the ring network box bus is collected within a signal collection time, a command is sent to control the outlet of the interval unit to trip, the fault is removed, and a trip signal is sent to the distribution terminal in the other interval unit adjacent to the topology of the interval unit; after the distribution terminal in the other interval unit adjacent to the topology of the interval unit receives the trip signal, a command is sent to trip the circuit breaker of the respective interval unit, and the fault is isolated; each distribution terminal acquires measurement data in the interval unit, and the measurement data comprises voltage, current and power; whether the preset CT disconnection bus protection condition is met is determined according to the measurement data; CT disconnection bus protection is performed in the case where it is determined that the preset CT disconnection bus protection condition is met; the CT disconnection bus protection is that the bus protection function of each interval unit distribution terminal is no longer logically judged and event processed; the preset CT disconnection bus protection condition is that: the maximum phase current is greater than 0.02In, and the maximum phase current is greater than 4 times any phase current; in the case where it is determined that the preset CT disconnection bus protection condition is met, CT disconnection bus protection is performed, which comprises the following steps: in the case where it is determined that the preset CT disconnection bus protection condition is met, a CT disconnection bus protection command is triggered after a preset time delay, and CT disconnection bus protection is performed.

2. The method of claim 1, wherein the bus protection method is a method of a primary and secondary fusion distribution network ring main unit. CT disconnection bus protection is performed when the GOOSE communication of the distribution terminal of each interval unit is abnormal.

3. A distribution network primary and secondary fusion complete ring network box bus protection device, characterized in that, The method is executed as claimed in claim 1, and the distribution network and secondary fusion complete ring network box bus protection device comprises a power supply side incoming line circuit breaker, a plurality of feeder circuit breakers, a ring network box bus, and a plurality of distribution terminals; the inflow current of the distribution network and secondary fusion complete ring network box flows into the ring network box bus through the power supply side incoming line circuit breaker, and then flows into the plurality of feeder circuit breakers from the ring network box bus and then flows out; each circuit breaker is connected with one distribution terminal respectively, and each distribution terminal is used for collecting and controlling the connected circuit breaker; each circuit breaker and the connected distribution terminal form an interval unit, and the distribution terminals can communicate with each other; the non-terminal circuit breaker on the main line or large branch line in the distribution network and secondary fusion complete ring network box is a sectionalizing switch; the distribution terminal corresponding to the sectionalizing switch is used for issuing a command to control the outlet tripping of the interval unit after detecting a fault trigger node fault signal and without receiving a node fault signal of any other interval loop distribution terminal on the ring network box bus within a signal collection time, completing fault removal, and sending a tripping signal to the distribution terminal in the other interval unit adjacent to the topology of the interval unit; the distribution terminal in the other interval unit adjacent to the topology of the interval unit is used for issuing a command to trip the circuit breaker of the respective interval unit after receiving the tripping signal, and completing fault isolation.

4. The network of claim 3, wherein the bus protection device is characterized by, Each distribution terminal is also used for acquiring measurement data in the interval unit, the measurement data comprising voltage, current, and power; judging whether a preset CT disconnection bus protection condition is met according to the measurement data; and performing CT disconnection bus protection in the case where it is judged that the preset CT disconnection bus protection condition is met; the CT disconnection bus protection is that the bus protection function of each interval unit distribution terminal no longer performs logical judgment and event processing.

5. The network of primary and secondary fusion ring main-tie-up box bus protection device according to claim 4, characterized in that, The preset CT disconnection bus protection condition is that a maximum phase current is greater than 0.02In, and the maximum phase current is greater than 4 times any phase current. Each distribution terminal is also specifically used for triggering a CT disconnection bus protection command to perform CT disconnection bus protection after a preset time delay in the case where it is judged that the preset CT disconnection bus protection condition is met.

6. The network of claim 4, wherein the bus protection device is characterized by, The distribution terminal of each interval unit is also used for performing CT disconnection bus protection when GOOSE communication is abnormal.

7. The network of claim 4, characterized in that, ​

Images