Intelligent ring closing device and method for low-voltage distribution station

Abstract

The application provides a low-voltage power distribution station intelligent loop closing device and method, the device comprises: a voltage acquisition module; a current acquisition module; a switch position detection module, which is used for acquiring position information of #1 and #2 low-voltage total switches and a bus tie switch; and a controller, which is used for controlling the bus tie switch, the #1 low-voltage total switch and the #2 low-voltage total switch according to the voltage at the upper end of the #1 and #2 low-voltage total switches, the current of the #1 low-voltage total switch, the current of the #2 low-voltage total switch, the current of the bus tie switch and the position information, so as to perform a hot reverse power supply operation and a hot reverse recovery operation. The application can realize automatic checking of a loop closing condition of a low-voltage power distribution station and perform a hot reverse power supply operation and a hot reverse recovery operation, reduces manual operation of checking of the loop closing condition, shortens user power outage time, directly creates economic and social benefits for users and power supply companies, and further greatly improves the power distribution automation level.

Description

Technical Field

[0001] This invention relates to the field of power transmission and distribution equipment technology, specifically to an intelligent loop closing device and a method for intelligent loop closing in a low-voltage substation. Background Technology

[0002] In traditional 10kV low-voltage substations, parallel operation of two transformers is not permitted. The closing operation of the bus tie switch is mechanically and electrically interlocked with the #1 and #2 low-voltage main switches. When the #1 and #2 low-voltage main switches are in the closed position, the bus tie switch cannot be closed. This results in the inability to perform loop-closing operation through the bus tie switch during maintenance of the low-voltage main switch or transformer equipment. Since hot-swapping is not possible, power outages may occur for users during load transfer.

[0003] As residents demand higher reliability of electricity, in order to prevent power outages for residents during equipment maintenance, it is necessary to implement hot switching operation of the bus tie in 10kV power distribution substations to complete the 0.4kV hot switching of power supply to the substation. Residents' power is not allowed to be interrupted during the hot switching process.

[0004] In related technologies, heat transfer switching is generally operated manually on-site, requiring manual verification of various electrical data and determination of whether the bus tie-off is ready for loop closure. This manual operation method suffers from low efficiency and is easily affected by subjective human factors. It not only has a low degree of automation but also low efficiency, which is not conducive to its widespread application. Summary of the Invention

[0005] To solve the above-mentioned technical problems, the first objective of this invention is to propose an intelligent loop-closing device for low-voltage substations.

[0006] The second objective of this invention is to propose an intelligent loop-closing method for low-voltage substations.

[0007] The technical solution adopted in this invention is as follows:

[0008] An embodiment of the first aspect of the present invention provides an intelligent loop-closing device for a low-voltage substation. The low-voltage substation includes a first substation and a second substation. The first substation includes a first transformer, the primary side of which is connected to a 10kV busbar via a #1 high-voltage main switch, and the secondary side of which is connected to a first 0.4kV busbar via a #1 low-voltage main switch. The second substation includes a second transformer, the primary side of which is connected to a 10kV busbar via a #2 high-voltage main switch, and the secondary side of which is connected to a second 0.4kV busbar via a #2 low-voltage main switch. The first 0.4kV busbar and the second 0.4kV busbar are connected via a bus tie switch. The intelligent loop-closing device includes a voltage acquisition module, which is used to acquire the voltage at the upper end of the #1 low-voltage main switch and the voltage at the #2 low-voltage main switch. The system includes: a main switch voltage; a current acquisition module for acquiring the current of the #1 low-voltage main switch, the #2 low-voltage main switch, and the bus tie switch; a switch position detection module for acquiring the position information of the #1 low-voltage main switch, the #2 low-voltage main switch, and the bus tie switch; and a controller connected to the voltage acquisition module, the current acquisition module, and the switch position detection module. The controller is used to control the bus tie switch, the #1 low-voltage main switch, and the #2 low-voltage main switch based on the voltage at the top of the #1 low-voltage main switch, the voltage at the top of the #2 low-voltage main switch, the current of the #1 low-voltage main switch, the current of the #2 low-voltage main switch, the current of the bus tie switch, and the position information, to perform hot-swap power supply operation and hot-swap recovery operation.

[0009] The intelligent loop closing device for low-voltage substations proposed in this invention may also have the following additional technical features:

[0010] According to one embodiment of the present invention, the controller is specifically configured to: determine whether the voltage at the upper end of the #1 low-voltage main switch and the voltage at the upper end of the #2 low-voltage main switch meet a first set condition, wherein the first set condition includes: the absolute value of the phase difference between the voltages at the upper ends of the #1 low-voltage main switch and the #2 low-voltage main switch is lower than a preset degree and the voltage difference is less than a preset difference; if the first set condition is met, further determine whether the superimposed load rate of the #1 low-voltage main switch and the #2 low-voltage main switch meets a second set condition, wherein the second set condition includes: the sum of the currents of the #1 low-voltage main switch and the #2 low-voltage main switch is less than or equal to a preset current; if the second set condition is met, Then, a loop-closing permission signal is sent; the control dispatcher initiates a bus tie loop command to control the bus tie switch to close; the location information of the bus tie switch is used to determine whether the bus tie closing is successful; if the bus tie switch closes successfully, it is further determined whether the voltage at the upper end of the #1 low-voltage main switch, the voltage at the upper end of the #2 low-voltage main switch, and the current of the bus tie switch meet the third set condition, the third set condition including: the voltage values ​​at the upper ends of the #1 low-voltage main switch and the #2 low-voltage main switch are within a preset voltage range, and the current value of the bus tie switch is within a preset current range; if the third set condition is met, the dispatcher sends a #1 low-voltage main switch tripping command to complete the hot-swap operation.

[0011] According to one embodiment of the present invention, the controller is specifically configured to: determine whether the voltage at the upper end of the #1 low-voltage main switch and the voltage at the upper end of the #2 low-voltage main switch meet a first set condition, wherein the first set condition includes: the absolute value of the phase difference between the voltages at the upper ends of the #1 low-voltage main switch and the #2 low-voltage main switch is lower than a preset degree and the voltage difference is less than a preset difference; if the first set condition is met, then send a loop-closing permission signal; control the scheduling to initiate a loop-closing command for the #1 low-voltage main switch to control the #1 low-voltage main switch to close; and determine the position of the #1 low-voltage main switch. The system determines whether the closing of the #1 low-voltage main switch was successful. If the #1 low-voltage main switch was successfully closed, it further determines whether the voltage at the upper end of the #1 low-voltage main switch, the voltage at the upper end of the #2 low-voltage main switch, and the current of the bus tie switch meet the third set condition. The third set condition includes that the voltage values ​​at the upper ends of the #1 and #2 low-voltage main switches are within a preset voltage range, and the current value of the bus tie switch is within a preset current range. If the third set condition is met, a bus tie tripping command is sent through scheduling to complete the hot-swap recovery operation.

[0012] According to one embodiment of the present invention, the controller transmits the loop-closing enable signal via IEC104 (Telecontrol Equipment and Systems - Part 5-104, an international standard applied to the power industry).

[0013] According to one embodiment of the present invention, the current acquisition module acquires the current of the #1 low-voltage main switch, the current of the #2 low-voltage main switch and the current of the bus tie switch through an open-loop CT (Current Transformer).

[0014] A second aspect of the present invention provides an intelligent loop-closing method for a low-voltage substation, the low-voltage substation comprising: a first substation and a second substation, the first substation comprising a first transformer, the primary side of the first transformer being connected to a 10kV busbar via a #1 high-voltage main switch, and the secondary side of the first transformer being connected to a first 0.4kV busbar via a #1 low-voltage main switch; the second substation comprising a second transformer, the primary side of the second transformer being connected to a 10kV busbar via a #2 high-voltage main switch, and the secondary side of the second transformer being connected to a second 0.4kV busbar via a #2 low-voltage main switch; the first 0.4kV busbar and the second 0.4kV busbar are connected via a bus tie switch. The intelligent loop closing method includes the following steps: acquiring the voltage at the upper end of the #1 low-voltage main switch and the voltage at the upper end of the #2 low-voltage main switch; acquiring the current of the #1 low-voltage main switch, the current of the #2 low-voltage main switch, and the current of the bus tie switch; acquiring the position information of the #1 low-voltage main switch, the #2 low-voltage main switch, and the bus tie switch; and controlling the bus tie switch, the #1 low-voltage main switch, and the #2 low-voltage main switch based on the voltage at the upper end of the #1 low-voltage main switch, the voltage at the upper end of the #2 low-voltage main switch, the current of the #1 low-voltage main switch, the current of the #2 low-voltage main switch, the current of the bus tie switch, and the position information to perform hot-swap power supply operation and hot-swap recovery operation.

[0015] The intelligent loop closing method for low-voltage substations proposed in this invention may also have the following additional technical features:

[0016] According to an embodiment of the present invention, the thermal reversal operation is specifically performed through the following steps: determining whether the voltage at the upper end of the #1 low-voltage main switch and the voltage at the upper end of the #2 low-voltage main switch meet a first set condition, wherein the first set condition includes: the absolute value of the phase difference between the upper ends of the #1 low-voltage main switch and the #2 low-voltage main switch is lower than a preset degree and the voltage difference is less than a preset difference; if the first set condition is met, further determining whether the superimposed load rate of the #1 low-voltage main switch and the #2 low-voltage main switch meets a second set condition, wherein the second set condition includes: the sum of the currents of the #1 low-voltage main switch and the #2 low-voltage main switch is less than or equal to a preset current; if the second set condition is met... If the set conditions are met, a loop-closing permission signal is sent; the control dispatcher initiates a bus tie loop command to control the closing of the bus tie switch; the location information of the bus tie switch is used to determine whether the bus tie closing is successful; if the bus tie switch is successfully closed, it is further determined whether the voltage at the upper end of the #1 low-voltage main switch, the voltage at the upper end of the #2 low-voltage main switch, and the current of the bus tie switch meet the third set conditions, the third set conditions including: the voltage values ​​at the upper ends of the #1 low-voltage main switch and the #2 low-voltage main switch are within a preset voltage range, and the current value of the bus tie switch is within a preset current range; if the third set conditions are met, the dispatcher sends a #1 low-voltage main switch tripping command to complete the hot-swap power supply operation.

[0017] According to an embodiment of the present invention, the hot recovery operation is specifically performed through the following steps: determining whether the voltage at the upper end of the #1 low-voltage main switch and the voltage at the upper end of the #2 low-voltage main switch meet a first set condition, wherein the first set condition includes: the absolute value of the phase difference between the upper ends of the #1 low-voltage main switch and the #2 low-voltage main switch is lower than a preset degree and the voltage difference is less than a preset difference; if the first set condition is met, a loop closing permission signal is sent; the control dispatcher initiates a loop closing command for the #1 low-voltage main switch to control the #1 low-voltage main switch to close; according to the #1 low-voltage main switch... The position information of the switches determines whether the closing of the #1 low-voltage main switch was successful. If the closing of the #1 low-voltage main switch was successful, it is further determined whether the voltage at the upper end of the #1 low-voltage main switch, the voltage at the upper end of the #2 low-voltage main switch, and the current of the bus tie switch meet the third set condition. The third set condition includes: the voltage values ​​at the upper ends of the #1 and #2 low-voltage main switches are within a preset voltage range, and the current value of the bus tie switch is within a preset current range. If the third set condition is met, a bus tie tripping command is sent through scheduling to complete the hot-swap recovery operation.

[0018] According to one embodiment of the present invention, the loop closing enable signal is transmitted via IEC104.

[0019] According to one embodiment of the present invention, the current of the #1 low-voltage main switch, the current of the #2 low-voltage main switch, and the current of the bus tie switch are collected by an open-loop CT.

[0020] The beneficial effects of this invention are:

[0021] This invention enables automatic verification of loop closure conditions and hot-swap power supply and hot-swap recovery operations in low-voltage substations, reducing the need for manual verification of loop closure conditions. It not only prevents power outages to residential loads but also directly creates economic and social benefits for users and power supply companies, further significantly improving the level of power distribution automation.

[0022] This invention features remote communication capabilities, supports remote control, and can upload detection results to the distribution network automation master station system. When the distribution network master station performs loop-closing operations, the device automatically determines synchronization conditions and superimposed load rates, ensuring the accuracy of the loop-closing operation, reducing the workload of manual on-site loop-closing operations, shortening the time for disengaging and reclosing distribution lines, and significantly improving work efficiency. Attached Figure Description

[0023] Figure 1 This is a block diagram of an intelligent loop closing device for a low-voltage substation according to an embodiment of the present invention.

[0024] Figure 2 This is a schematic diagram of a low-voltage substation according to an embodiment of the present invention;

[0025] Figure 3 This is a flowchart of a thermal inversion operation according to an embodiment of the present invention;

[0026] Figure 4 This is a flowchart of a thermal recovery operation according to an embodiment of the present invention;

[0027] Figure 5 This is a flowchart of an intelligent loop closure method according to an embodiment of the present invention. Detailed Implementation

[0028] The technical solutions of 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 some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] Figure 1 This is a block diagram of an intelligent loop-closing device for a low-voltage substation according to an embodiment of the present invention, wherein, as Figure 2As shown, the low-voltage substation includes: a first substation A and a second substation B. The first substation A includes a first transformer T1. The primary side of the first transformer T1 is connected to the 10kV busbar via the #1 high-voltage main switch, and the secondary side of the first transformer T1 is connected to the first 0.4kV busbar L1 via the #1 low-voltage main switch. The second substation B includes a second transformer T2. The primary side of the second transformer T2 is connected to the 10kV busbar via the #2 high-voltage main switch, and the secondary side of the second transformer T2 is connected to the second 0.4kV busbar L2 via the #2 low-voltage main switch. The first 0.4kV busbar L1 and the second 0.4kV busbar L2 are connected via a bus tie switch K. Both the first substation A and the second substation B are 110kV substations.

[0030] like Figure 1 As shown, the intelligent loop closing device includes: a voltage acquisition module 1, a current acquisition module 2, a switch position detection module 3, and a controller 4. The voltage acquisition module 1 is used to acquire the voltage at the upper end of the #1 low-voltage main switch and the voltage at the upper end of the #2 low-voltage main switch; the current acquisition module 2 is used to acquire the current of the #1 low-voltage main switch, the current of the #2 low-voltage main switch, and the current of the bus tie switch; the switch position detection module 3 is used to acquire the position information of the #1 low-voltage main switch, the #2 low-voltage main switch, and the bus tie switch; the controller 4 is connected to the voltage acquisition module 1, the current acquisition module 2, and the switch position detection module 3 respectively. The controller 4 is used to control the bus tie switch, the #1 low-voltage main switch, and the #2 low-voltage main switch based on the voltage at the upper end of the #1 low-voltage main switch, the voltage at the upper end of the #2 low-voltage main switch, the current of the #1 low-voltage main switch, the current of the #2 low-voltage main switch, the current of the bus tie switch, and the position information, in order to perform hot-swap power supply operation and hot-swap recovery operation.

[0031] In one specific embodiment of the present invention, the current acquisition module 2 acquires the current of the #1 low-voltage main switch, the current of the #2 low-voltage main switch and the current of the bus tie switch through an open-loop CT.

[0032] Specifically, controller 4 may include an A / D (analog-to-digital) conversion unit to convert the analog signals acquired by voltage acquisition module 1 and current acquisition module 2 into digital signals. Voltage acquisition module 1 can be a voltage transformer, which can convert the three-phase voltage signal into a smaller signal for acquisition, so that controller 4 can directly identify it. Current acquisition module 2 acquires the current of #1 low-voltage main switch, #2 low-voltage main switch, and bus tie switch through an open-loop CT. The open-loop CT can convert the acquired current signal into a smaller signal for controller 4 to identify. The acquisition error of the open-loop CT can be controlled within 5%. The open-loop CT can be directly installed on the line where the current to be detected is located. An optocoupler isolation unit can be set between the acquisition switch position detection module 3 and controller 4, such as... Figure 1As shown, controller 4 can control bus tie switch K, #1 low-voltage main switch and #2 low-voltage main switch through drive circuit 5. This enables automatic verification of loop closure conditions and hot-swap and hot-restore operations in low-voltage substations, reducing manual verification of loop closure conditions. This not only prevents power outages to residential loads but also directly creates economic and social benefits for users and the power company, significantly improving the level of distribution automation.

[0033] The following describes, with reference to specific embodiments, how controller 4 performs hot-swap supply operation and hot-swap recovery operation.

[0034] According to one embodiment of the present invention, such as Figure 3 As shown, controller 4 specifically employs the following steps to perform hot-swapping operation:

[0035] S101, determine whether the voltage at the upper end of low-voltage main switch #1 and the voltage at the upper end of low-voltage main switch #2 meet the first set condition, wherein the first set condition includes: the absolute value of the phase difference between the voltages at the upper ends of low-voltage main switches #1 and #2 is lower than a preset degree and the voltage difference is less than a preset difference. If the condition is met, proceed to step S102; if the condition is not met, continue to proceed to step S101.

[0036] The preset degree can be 5 degrees, the preset difference can be 1% of the secondary voltage of the transformer, and the preset difference can be 4V.

[0037] S102, determine whether the combined load rate of low-voltage main switch #1 and low-voltage main switch #2 meets the second set condition. The second set condition includes: the sum of the currents of low-voltage main switch #1 and low-voltage main switch #2 is less than or equal to a preset current. If it meets the condition, proceed to step S103; otherwise, return to step S101.

[0038] Among them, the superimposed load rate (the sum of the currents of the #1 low-voltage main switch and the #2 low-voltage main switch) should not exceed 80% of the load rate of a single transformer, that is, the preset current should not exceed 80% of the rated current of T1 or T2.

[0039] S103 sends the loop closing enable signal.

[0040] In one specific embodiment of the present invention, the controller 4 sends a loop-closing enable signal via IEC 104. Furthermore, the controller 4 performs IEC 104 communication via an Ethernet module and an Ethernet fiber optic cable.

[0041] S104, the control dispatcher initiates a bus tie loop command to control the bus tie switch to close.

[0042] S105: Determine whether the bus tie switch closing was successful based on the position information of the bus tie switch. If the bus tie switch closing was successful, proceed to step S106; otherwise, return to step S101.

[0043] S106, determine whether the voltage at the upper end of the #1 low-voltage main switch, the voltage at the upper end of the #2 low-voltage main switch, and the current of the bus tie switch meet the third set condition. The third set condition includes: the voltage values ​​at the upper ends of the #1 and #2 low-voltage main switches are within a preset voltage range, and the current value of the bus tie switch is within a preset current range. If the third set condition is met, proceed to step S107; otherwise, proceed to step S108 and return to step S101.

[0044] The preset voltage range and preset current range are set according to the actual situation. For example, the preset voltage range can be [-1% of the rated voltage of the transformer secondary side, +1% of the rated voltage of the transformer secondary side], and the preset current range can be [-1% of the rated current of the transformer, +1% of the rated current of the transformer].

[0045] S107 sends a trip command to the #1 low-voltage main switch via dispatch to complete the hot-switching operation.

[0046] S108, trip the bus tie switch.

[0047] According to one embodiment of the present invention, such as Figure 4 As shown, controller 4 specifically performs the hot recovery operation using the following steps:

[0048] S201, determine whether the voltage at the upper end of low-voltage main switch #1 and the voltage at the upper end of low-voltage main switch #2 meet the first set condition, wherein the first set condition includes: the absolute value of the phase difference between the voltages at the upper ends of low-voltage main switches #1 and #2 is lower than a preset degree and the voltage difference is less than a preset difference. If the first set condition is met, proceed to step S202; if the first set condition is not met, continue to proceed to step S201.

[0049] S202, send loop closing enable signal.

[0050] S203, the control dispatcher initiates a loop closing command for the #1 low-voltage main switch to control the #1 low-voltage main switch to close.

[0051] S204. Determine whether the closing of the #1 low-voltage main switch was successful based on the position information of the #1 low-voltage main switch. If successful, proceed to step S205; otherwise, return to step S201.

[0052] S205, determine whether the voltage at the upper end of low-voltage main switch #1, the voltage at the upper end of low-voltage main switch #2, and the current of the bus tie switch meet the third set condition. The third set condition includes: the voltage values ​​at the upper ends of low-voltage main switches #1 and #2 are within a preset voltage range, and the current value of the bus tie switch is within a preset current range. If the third set condition is met, proceed to step S206; if the third set condition is not met, proceed to step S207 and then return to step S201.

[0053] S206 sends a bus tie trip command through scheduling to complete the hot-swap recovery operation.

[0054] S207, control #1 low-voltage main switch tripped.

[0055] In summary, the intelligent loop-closing device for low-voltage substations according to embodiments of the present invention can automatically verify loop-closing conditions and perform hot-swap and hot-restore operations, reducing manual verification of loop-closing conditions. This not only prevents power outages to residential loads but also directly creates economic and social benefits for users and power companies, significantly improving the level of distribution automation. It has remote communication capabilities, supports remote control, and can transmit detection results to the distribution network automation master station system via IEC104. When the distribution network master station performs loop-closing operations, the device automatically judges synchronization conditions and superimposed load rates, ensuring the accuracy of the loop-closing operation, reducing the workload of manual on-site loop-closing operations, shortening the time for disengaging and reclosing distribution lines, and significantly improving work efficiency.

[0056] Corresponding to the aforementioned intelligent loop closing device for low-voltage substations, this invention also proposes an intelligent loop closing method for low-voltage substations.

[0057] like Figure 2 As shown, the low-voltage substation includes: a first substation A and a second substation B. The first substation A includes a first transformer T1. The primary side of the first transformer T1 is connected to the 10kV bus via the #1 high-voltage main switch, and the secondary side of the first transformer T1 is connected to the first 0.4kV bus L1 via the #1 low-voltage main switch. The second substation B includes a second transformer T2. The primary side of the second transformer T2 is connected to the 10kV bus via the #2 high-voltage main switch, and the secondary side of the second transformer T2 is connected to the second 0.4kV bus L2 via the #2 low-voltage main switch. The first 0.4kV bus L1 and the second 0.4kV bus L2 are connected by a bus tie switch K.

[0058] like Figure 5 As shown, the intelligent loop closure method includes the following steps:

[0059] S1, collect the voltage at the upper end of the #1 low-voltage main switch and the voltage at the upper end of the #2 low-voltage main switch.

[0060] S2 collects the current of the #1 low-voltage main switch, the current of the #2 low-voltage main switch, and the current of the bus tie switch.

[0061] S3, collect the location information of #1 low-voltage main switch, #2 low-voltage main switch and bus tie switch.

[0062] S4 controls the bus tie switch, the #1 low-voltage main switch, and the #2 low-voltage main switch based on the voltage at the upper end of the #1 low-voltage main switch, the current of the #1 low-voltage main switch, the current of the #2 low-voltage main switch, the current of the bus tie switch, and the position information, so as to perform hot reverse supply operation and hot reverse recovery operation.

[0063] According to one embodiment of the present invention, such as Figure 3 As shown, the specific steps for performing the heat reversal operation are as follows:

[0064] S101, determine whether the voltage at the upper end of low-voltage main switch #1 and the voltage at the upper end of low-voltage main switch #2 meet the first set condition, wherein the first set condition includes: the absolute value of the phase difference between the voltages at the upper ends of low-voltage main switches #1 and #2 is lower than a preset degree and the voltage difference is less than a preset difference. If the condition is met, proceed to step S102; if the condition is not met, continue to proceed to step S101.

[0065] The preset degree can be 5 degrees, the preset difference can be 1% of the secondary voltage of the transformer, and the preset difference can be 4V.

[0066] S102, determine whether the combined load rate of low-voltage main switch #1 and low-voltage main switch #2 meets the second set condition. The second set condition includes: the sum of the currents of low-voltage main switch #1 and low-voltage main switch #2 is less than or equal to a preset current. If it meets the condition, proceed to step S103; otherwise, return to step S101.

[0067] Among them, the superimposed load rate (the sum of the currents of the #1 low-voltage main switch and the #2 low-voltage main switch) should not exceed 80% of the load rate of a single transformer, that is, the preset current should not exceed 80% of the rated current of T1 or T2.

[0068] S103 sends the loop closing enable signal.

[0069] In one specific embodiment of the present invention, the controller 4 sends a loop-closing enable signal via IEC 104. Furthermore, the controller 4 performs IEC 104 communication via an Ethernet module and an Ethernet fiber optic cable.

[0070] S104, the control dispatcher initiates a bus tie loop command to control the bus tie switch to close.

[0071] S105: Determine whether the bus tie switch closing was successful based on the position information of the bus tie switch. If the bus tie switch closing was successful, proceed without going to step S106; otherwise, return to step S101.

[0072] S106, determine whether the voltage at the upper end of the #1 low-voltage main switch, the voltage at the upper end of the #2 low-voltage main switch, and the current of the bus tie switch meet the third set condition. The third set condition includes: the voltage values ​​at the upper ends of the #1 and #2 low-voltage main switches are within a preset voltage range, and the current value of the bus tie switch is within a preset current range. If the third set condition is met, proceed to step S107; otherwise, proceed to step S108 and return to step S101.

[0073] The preset voltage range and preset current range are set according to the actual situation. For example, the preset voltage range can be [-1% of the rated voltage of the transformer secondary side, +1% of the rated voltage of the transformer secondary side], and the preset current range can be [-1% of the rated current of the transformer, +1% of the rated current of the transformer].

[0074] S107 sends a trip command to the #1 low-voltage main switch via dispatch to complete the hot-switching operation.

[0075] S108, trip the bus tie switch.

[0076] According to one embodiment of the present invention, such as Figure 4 As shown, the following steps are used to perform the hot recovery operation:

[0077] S201, determine whether the voltage at the upper end of the #1 low-voltage main switch and the voltage at the upper end of the #2 low-voltage main switch meet the first set condition, wherein the first set condition includes: the absolute value of the phase difference between the voltages at the upper ends of the #1 low-voltage main switch and the #2 low-voltage main switch is lower than a preset degree and the voltage difference is less than a preset difference; if the first set condition is met, proceed to step S202; if the first set condition is not met, continue to proceed to step S201.

[0078] S202, send loop closing enable signal.

[0079] S203, the control dispatcher initiates a loop closing command for the #1 low-voltage main switch to control the #1 low-voltage main switch to close.

[0080] S204. Determine whether the closing of the #1 low-voltage main switch was successful based on the position information of the #1 low-voltage main switch. If successful, proceed to step one, S205; otherwise, return to step S201.

[0081] S205, determine whether the voltage at the upper end of low-voltage main switch #1, the voltage at the upper end of low-voltage main switch #2, and the current of the bus tie switch meet the third set condition. The third set condition includes: the voltage values ​​at the upper ends of low-voltage main switches #1 and #2 are within a preset voltage range, and the current value of the bus tie switch is within a preset current range. If the third set condition is met, proceed to step S206; if the third set condition is not met, proceed to step S207 and then return to step S201.

[0082] S206 sends a bus tie trip command through scheduling to complete the hot-swap recovery operation.

[0083] S207, control #1 low-voltage main switch tripped.

[0084] In summary, the intelligent loop-closing method for low-voltage substations according to embodiments of the present invention can automatically verify loop-closing conditions and perform hot-swap and hot-restore operations, reducing manual verification of loop-closing conditions. This not only avoids power outages to residential loads but also directly creates economic and social benefits for users and power companies, significantly improving the level of distribution automation. It has remote communication capabilities, supports remote control, and can transmit detection results to the distribution network automation master station system via IEC104. When the distribution network master station performs loop-closing operations, the device automatically judges synchronization conditions and superimposed load rates, ensuring the accuracy of the loop-closing operation, reducing the workload of manual on-site loop-closing operations, shortening the time for disengaging and reclosing distribution lines, and significantly improving work efficiency.

[0085] In the description of this invention, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. "A plurality of" means two or more, unless otherwise explicitly specified.

[0086] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the communication within the compartments of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0087] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0088] In this specification, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, those skilled in the art can combine and integrate the different embodiments or examples and features described in this specification without contradiction. Furthermore, those skilled in the art can combine and integrate the different embodiments or examples described herein, as well as the features of the different embodiments or examples, without contradiction.

[0089] Any process or method description in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or more executable instructions for implementing custom logic functions or processes, and the scope of preferred embodiments of the invention includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as should be understood by those skilled in the art to which embodiments of the invention pertain.

[0090] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include: an electrical connection having one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Alternatively, the computer-readable medium may be paper or other suitable media on which the program can be printed, since the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in a computer memory.

[0091] It should be understood that various parts of the present invention can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware as in another embodiment, it can be implemented using any of the following techniques known in the art, or a combination thereof: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0092] Those skilled in the art will understand that all or part of the steps of the methods in the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, the program includes one or a combination of the steps of the method embodiments.

[0093] Furthermore, the functional units in the various embodiments of the present invention can be integrated into a processing module, or each unit can exist physically separately, or two or more units can be integrated into a module. The integrated module can be implemented in hardware or as a software functional module. If the integrated module is implemented as a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium.

[0094] The storage medium mentioned above can be a read-only memory, a disk, or an optical disk, etc. Although embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

[0095] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A smart loop closing device for a low-voltage substation, characterized in that, The low-voltage substation includes: a first substation and a second substation. The first substation includes a first transformer. The primary side of the first transformer is connected to the 10kV busbar through the #1 high-voltage main switch, and the secondary side of the first transformer is connected to the first 0.4kV busbar through the #1 low-voltage main switch. The second substation includes a second transformer. The primary side of the second transformer is connected to the 10kV busbar through the #2 high-voltage main switch, and the secondary side of the second transformer is connected to the second 0.4kV busbar through the #2 low-voltage main switch. The first 0.4kV busbar and the second 0.4kV busbar are connected by a bus tie switch. The intelligent loop closing device includes: A voltage acquisition module is used to acquire the voltage at the upper end of the #1 low-voltage main switch and the voltage at the upper end of the #2 low-voltage main switch. A current acquisition module is used to acquire the current of the #1 low-voltage main switch, the current of the #2 low-voltage main switch, and the current of the bus tie switch. A switch position detection module is used to collect the position information of the #1 low-voltage main switch, the #2 low-voltage main switch and the bus tie switch; The controller is connected to the voltage acquisition module, the current acquisition module, and the switch position detection module respectively. The controller is used to control the bus tie switch, the #1 low-voltage main switch, and the #2 low-voltage main switch based on the voltage at the upper end of the #1 low-voltage main switch, the voltage at the upper end of the #2 low-voltage main switch, the current of the #1 low-voltage main switch, the current of the #2 low-voltage main switch, the current of the bus tie switch, and the position information, so as to perform hot reverse power supply operation and hot reverse recovery operation. The controller is specifically used for: Determine whether the voltage at the upper end of the #1 low-voltage main switch and the voltage at the upper end of the #2 low-voltage main switch meet the first set condition, wherein the first set condition includes: the absolute value of the phase difference between the voltages at the upper ends of the #1 low-voltage main switch and the #2 low-voltage main switch is lower than a preset degree and the voltage difference is less than a preset difference. If the first setting condition is met, it is further determined whether the superimposed load rate of the #1 low-voltage main switch and the #2 low-voltage main switch meets the second setting condition. The second setting condition includes: the sum of the currents of the #1 low-voltage main switch and the #2 low-voltage main switch is less than or equal to a preset current. If the second set condition is met, a loop closing enable signal is sent. The control and scheduling department initiates a bus tie loop command to control the closing of the bus tie switch; Determine whether the bus tie-off was successful based on the location information of the bus tie switch; If the bus tie switch is successfully closed, it is further determined whether the voltage at the upper end of the #1 low-voltage main switch, the voltage at the upper end of the #2 low-voltage main switch, and the current of the bus tie switch meet the third setting condition. The third setting condition includes: the voltage values ​​at the upper ends of the #1 low-voltage main switch and the #2 low-voltage main switch are within a preset voltage range, and the current value of the bus tie switch is within a preset current range. If the third set condition is met, the #1 low-voltage main switch tripping command is sent through the scheduling to complete the hot-switching operation; The controller is specifically used for: Determine whether the voltage at the upper end of the #1 low-voltage main switch and the voltage at the upper end of the #2 low-voltage main switch meet the first set condition, wherein the first set condition includes: the absolute value of the phase difference between the voltages at the upper ends of the #1 low-voltage main switch and the #2 low-voltage main switch is lower than a preset degree and the voltage difference is less than a preset difference. If the first set condition is met, a loop closing enable signal is sent. The control and dispatch system initiates a loop-closing command for the #1 low-voltage main switch to control the closing of the #1 low-voltage main switch; Determine whether the closing of the #1 low-voltage main switch was successful based on the location information of the #1 low-voltage main switch. If the #1 low-voltage main switch is successfully closed, it is further determined whether the voltage at the upper end of the #1 low-voltage main switch, the voltage at the upper end of the #2 low-voltage main switch, and the current of the bus tie switch meet the third setting condition. The third setting condition includes: the voltage values ​​at the upper ends of the #1 low-voltage main switch and the #2 low-voltage main switch are within a preset voltage range, and the current value of the bus tie switch is within a preset current range. If the third set condition is met, a bus tie trip command is sent via scheduling to complete the hot-swap recovery operation.

2. The intelligent loop closing device for low-voltage substations according to claim 1, characterized in that, The controller sends the loop closing enable signal via IEC104.

3. The intelligent loop-closing device for low-voltage substations according to claim 1, characterized in that, The current acquisition module acquires the current of the #1 low-voltage main switch, the current of the #2 low-voltage main switch, and the current of the bus tie switch through an open-loop CT.

4. A smart loop closing method for a low-voltage substation, characterized in that, The low-voltage substation includes: a first substation and a second substation. The first substation includes a first transformer. The primary side of the first transformer is connected to the 10kV busbar through the #1 high-voltage main switch, and the secondary side of the first transformer is connected to the first 0.4kV busbar through the #1 low-voltage main switch. The second substation includes a second transformer. The primary side of the second transformer is connected to the 10kV busbar through the #2 high-voltage main switch, and the secondary side of the second transformer is connected to the second 0.4kV busbar through the #2 low-voltage main switch. The first 0.4kV busbar and the second 0.4kV busbar are connected by a bus tie switch. The intelligent loop merging method includes the following steps: Collect the voltage at the upper end of the #1 low-voltage main switch and the voltage at the upper end of the #2 low-voltage main switch; Collect the current of the #1 low-voltage main switch, the current of the #2 low-voltage main switch, and the current of the bus tie switch; Collect the location information of the #1 low-voltage main switch, the #2 low-voltage main switch, and the bus tie switch; Based on the voltage at the upper end of the #1 low-voltage main switch, the voltage at the upper end of the #2 low-voltage main switch, the current of the #1 low-voltage main switch, the current of the #2 low-voltage main switch, the current of the bus tie switch, and the position information, the bus tie switch, the #1 low-voltage main switch, and the #2 low-voltage main switch are controlled to perform hot reverse supply operation and hot reverse recovery operation. The heat inversion operation is specifically performed through the following steps: Determine whether the voltage at the upper end of the #1 low-voltage main switch and the voltage at the upper end of the #2 low-voltage main switch meet the first set condition, wherein the first set condition includes: the absolute value of the phase difference between the voltages at the upper ends of the #1 low-voltage main switch and the #2 low-voltage main switch is lower than a preset degree and the voltage difference is less than a preset difference. If the first setting condition is met, it is further determined whether the superimposed load rate of the #1 low-voltage main switch and the #2 low-voltage main switch meets the second setting condition. The second setting condition includes: the sum of the currents of the #1 low-voltage main switch and the #2 low-voltage main switch is less than or equal to a preset current. If the second set condition is met, a loop closing enable signal is sent. The control and scheduling department initiates a bus tie loop command to control the closing of the bus tie switch; Determine whether the bus tie-off was successful based on the location information of the bus tie switch; If the bus tie switch is successfully closed, it is further determined whether the voltage at the upper end of the #1 low-voltage main switch, the voltage at the upper end of the #2 low-voltage main switch, and the current of the bus tie switch meet the third setting condition. The third setting condition includes: the voltage values ​​at the upper ends of the #1 low-voltage main switch and the #2 low-voltage main switch are within a preset voltage range, and the current value of the bus tie switch is within a preset current range. If the third set condition is met, the #1 low-voltage main switch tripping command is sent through the scheduling to complete the hot-switching operation; The heat recovery operation is performed through the following steps: Determine whether the voltage at the upper end of the #1 low-voltage main switch and the voltage at the upper end of the #2 low-voltage main switch meet the first set condition, wherein the first set condition includes: the absolute value of the phase difference between the voltages at the upper ends of the #1 low-voltage main switch and the #2 low-voltage main switch is lower than a preset degree and the voltage difference is less than a preset difference. If the first set condition is met, a loop closing enable signal is sent. The control and dispatch system initiates a loop-closing command for the #1 low-voltage main switch to control the closing of the #1 low-voltage main switch; Determine whether the closing of the #1 low-voltage main switch was successful based on the location information of the #1 low-voltage main switch. If the #1 low-voltage main switch is successfully closed, it is further determined whether the voltage at the upper end of the #1 low-voltage main switch, the voltage at the upper end of the #2 low-voltage main switch, and the current of the bus tie switch meet the third setting condition. The third setting condition includes: the voltage values ​​at the upper ends of the #1 low-voltage main switch and the #2 low-voltage main switch are within a preset voltage range, and the current value of the bus tie switch is within a preset current range. If the third set condition is met, a bus tie trip command is sent via scheduling to complete the hot-swap recovery operation.

5. The intelligent loop closing method for low-voltage substations according to claim 4, characterized in that, The loop closing enable signal is transmitted via IEC104.

6. The intelligent loop closing method for low-voltage substations according to claim 4, characterized in that, The current of the #1 low-voltage main switch, the current of the #2 low-voltage main switch, and the current of the bus tie switch are collected by an open-loop CT.

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