CN116111587A - A fast self-healing method for line faults in sub-dry distribution network - Google Patents

Abstract

The invention provides a quick self-healing method for line faults of a secondary trunk distribution network, which is based on a power grid structure comprising a main network, a branch network and a distribution automation device which are connected with each other, wherein the main network is a double-petal main network, and the branch network is a double-ring network consisting of four distribution chambers and comprising two branch loops; the line faults in the normal running state and the maintenance state in practical application account for more than 90% of the total faults of the power grid structure, and the self-healing method is provided by combining the fault occurrence points based on the two states, is reliable, quick and effective, and is worthy of popularization and application.

Description

A fast self-healing method for line faults in secondary dry distribution network

The present invention is a divisional application with application number: 2019114118637, name: a set of rapid self-healing method for distribution network application date: December 31, 2019.

technical field

The invention relates to a fast self-healing method for line faults in a sub-dry distribution network.

Background technique

The distribution network grid structure with double petals as the backbone network and double ring network as the branch network is a highly reliable grid structure with clear structure and good self-healing ability. The power grid structure includes interconnected backbone network, branch network and distribution automation device. The backbone network is a double-petal backbone network. In the double-ring network of the four power distribution rooms, the number of primary power distribution rooms is two, and the number of secondary power distribution rooms is two. For the branch loop, the ends of the two branch loops on the side of each primary power distribution room are connected one-to-one with the two busbars of a switching station in the backbone network, and the two secondary power distribution rooms are connected by connecting cables connected and open-loop operation; the distribution automation device adopts intelligent distributed feeder automation technology. It is powered by the switch station, with the public power distribution room as the key node, and adopts full cable construction to form a highly reliable branch network double-ring network connection structure.

The commonly used fast self-healing scheme for distribution automation usually adopts the form of "switch station feeder" overcurrent protection + "public power distribution room" intelligent distributed DTU device. In this scheme, the switch station feeder adopts overcurrent protection as the main protection; each bus section of the public power distribution room is equipped with an intelligent distributed DTU device.

DTU (Distribution Terminal Unit) is a switching station and ring network cabinet terminal equipment, generally installed in conventional switching stations (stations), outdoor small switching stations, ring network cabinets, small substations, box-type substations, etc. , to complete the acquisition and calculation of position signals, voltage, current, active power, reactive power, power factor, electric energy and other data of the switchgear, to open and close the switch, and to realize the fault identification, isolation and monitoring of the feeder switch Restoration of power supply to non-faulty areas. Some DTUs also have the function of protection and automatic input of backup power; the device has the functions of line light difference protection, bus differential protection, self-healing control function, overcurrent protection, zero sequence overcurrent protection, backup protection, failure protection and so on.

The scope of realizing distributed feeder automation is between the incoming line switches of the first-level public power distribution room at both ends of the double ring network. The 10kV bus section switch in each public power distribution room does not participate in the rapid self-healing process of power distribution automation.

Contents of the invention

Based on the network structure in the background technology, the purpose of the present invention is to solve the typical and most common line faults, and provide a fast and reliable method for the self-healing of the power grid.

In order to solve the problems of the technologies described above, the technical solution adopted by the present invention is to comprise the following steps:

S100: According to the DTU fault alarm signal, determine the power distribution room or switch station where the fault point is located;

S200: Determine the faulty line;

S300: Determine the loop where the faulty line is located;

S400: Determine the current grid operation state;

S500: Determine the switch connected to the faulty line; comprehensively study and judge the self-healing strategy, select the switch that needs to be opened from the switches connected to the faulty line, and open the switch, and determine whether the contact cable switch of the loop needs to be closed. and operate.

A further improvement is that when the main line line between the switch stations of the first loop is faulty, the S500 adopts the following steps: at this time, the main line outlet switch of the first switch station of the first loop and the second switch station of the first loop The trunk line incoming switch is connected to the faulty line; after comprehensive research and judgment, the main trunk line outgoing switch of the first switch station of the first loop is opened; the trunk line incoming switch of the second switching station of the first loop is opened. In the switch station with double petal operation, the contact cable switch of the first ring circuit is in the closed state, and no processing will be performed.

A further improvement is that the feeder line of one of the switching stations in the first loop is faulty, and the S500 adopts the following steps: at this time, the outgoing line switch of the first loop switching station is connected to the faulty line; The above-mentioned first ring circuit switch station feeder line switch is open; in the switch station with double petal operation, the contact cable switch is in the closed state, and no processing is performed.

A further improvement is that, if the bus line of the second switching station of the first loop is faulty, the S500 adopts the following steps: at this time, all feeder switches on the bus of the second switching station of the first loop are connected to it, and the first The incoming line switch of the main line of the second switch station of the loop, the contact cable switch of the first loop are connected with the faulty cable; after comprehensive research and judgment, all the switches of the feeder lines on the bus of the second switch station of the first loop are opened; Open the main line incoming switch of the second switch station of the first loop; open the contact cable switch of the first loop; keep the section switch between the busbar sections of the second switch station of the first loop open .

A further improvement is that, after the self-healing of the bus bar of the second switching station of the first loop is completed, the bus bar of the third switching station of the first loop fails again, and the following steps are adopted in the S500: at this time, the first loop All feeder line switches on the busbar of the third switching station are connected to it, and the main line incoming switch of the third switching station of the first loop and the main trunk line outgoing switch of the third switching station of the first loop are connected to the faulty cable; through comprehensive research and judgment, the Open all feeder line switches on the bus of the third switch station of the first loop; open the main line incoming switch of the third switch station of the first loop; open the main line outgoing switch of the third switch station of the first loop ;The section switch between the busbar sections of the third switch station of the first ring circuit remains in the open state; the main line incoming switch of the fourth switch station of the first ring circuit automatically opens; The section switch between the bus sections of the fourth switch station of the ring circuit is automatically closed.

A further improvement is that when the incoming line of the first-level power distribution room of the first loop is faulty during normal operation, the S500 adopts the following steps: at this time, only the incoming line switch of the first-level power distribution room of the first loop is connected to the faulty line , the switch is opened; the first loop contact cable switch is closed.

A further improvement is that, during normal operation, if the line between the first-level power distribution room of the first loop and the second-level power distribution room of the first loop fails, the S500 adopts the following steps: at this time, the first loop The outgoing line switch of the first-level power distribution room and the incoming line switch of the second-level power distribution room of the first loop are connected to the faulty line; after comprehensive research and judgment, the outgoing line switch of the first-level power distribution room of the first loop is opened; The switch of the incoming line switch of the second stage power distribution room of the first loop is opened; the tie switch of the first loop is closed.

A further improvement is that, during normal operation, if the bus line of the first-level power distribution room of the first loop fails, the S500 adopts the following steps: at this time, the incoming line switch of the first-level power distribution room of the first loop and the first The outlet switch of the first-level power distribution room of the first loop is connected to the faulty line; after comprehensive research and judgment, the incoming switch of the first-level power distribution room of the first loop is opened; the first-level power distribution of the first loop is The outlet switch of the room is opened; the contact switch of the first loop is closed.

A further improvement is that when the incoming line of the first-level power distribution room of the first loop is overhauled, and the incoming line of the first-level power distribution room of the first loop fails, the S500 described above adopts the following steps: At this time, only the second-level power distribution room of the second loop The incoming line switch of the first-level power distribution room is connected to the incoming line of the first-level power distribution room of the second loop; through comprehensive research and judgment, the switch of the first-level power distribution room of the second loop is opened; the second loop The contact switch is closed.

A further improvement is that when the line is overhauled in the first-level power distribution room of the second loop, the line failure between the first-level power distribution room of the second loop and the second-level power distribution room of the second loop, the said The S500 adopts the following steps: at this time, the outlet switch of the first-level power distribution room of the second loop and the incoming switch of the second-level power distribution room of the second loop are connected to the faulty line; Open the switch of the incoming line of the first-level power distribution room; open the switch of the outgoing line of the first-level power distribution room of the second loop; close the contact switch of the second loop.

A further improvement is that when the first-level power distribution room of the first loop is overhauled, and the bus line of the first-level power distribution room of the second loop is faulty, the S500 described above adopts the following steps: At this time, the first level of the second loop The incoming line switch of the first-level power distribution room and the outgoing line switch of the first-level power distribution room of the second loop are connected to the faulty line; after comprehensive research and judgment, the above-mentioned incoming line switch of the first-level power distribution room of the second loop is opened; The outlet switch of the first-level power distribution room of the second loop is opened; the contact switch of the second loop is closed.

A further improvement is that when the incoming line of the first-level power distribution room of the first loop is overhauled, and the bus line of the second-level power distribution room of the first loop fails, the S500 adopts the following steps: at this time, the first loop second The incoming line switch of the first-level power distribution room and the outgoing line switch of the second-level power distribution room of the first loop are connected to the faulty line; after comprehensive research and judgment, the above-mentioned incoming line switch of the second-level power distribution room of the first loop is opened; The outlet switch of the second-level power distribution room of the first loop is opened.

Beneficial effects of the present invention:

This method divides the power grid into two states of normal operation and maintenance. On this basis, it is subdivided according to the location of the fault occurrence point, and different solution steps are given for each different situation, making the self-healing process of the power grid very fast and effective. , this method is safe, concise and reliable, and it is worth popularizing and using.

Description of drawings

Fig. 1 is the structural schematic diagram of the composite network frame of the embodiment of the present invention;

FIG. 2 is a schematic diagram of a backbone network loop and a protection range in Embodiment 1 of the present invention;

Fig. 3 is a schematic diagram of failure points of the backbone network in Embodiment 1 of the present invention;

Fig. 4 is a schematic diagram of a distribution automation intelligent distributed DTU configuration scheme in Embodiment 2 of the present invention;

Fig. 5 is a schematic diagram of failure points during normal operation of the branch line network in Embodiment 2 of the present invention;

Fig. 6 is a schematic diagram of failure points during maintenance of branch line network in embodiment 3 of the present invention;

In Figure 1: 1-1 the first substation, 1-2 the second substation, 2-1 the first switching station, 2-2 the second switching station, 2-3 the third switching station, 2-4 the fourth switching station, 3-1 first power distribution room, 3-2 second power distribution room, 3-3 third power distribution room, 3-4 fourth power distribution room.

Detailed ways

The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

As shown in Figure 1, the application of this method is based on a composite grid structure with reliable power supply, including a backbone network and a branch network connected to each other. The backbone network is a double-petal backbone network, and the branch network is composed of four The power distribution room consists of a double-ring network with two branch loops. Among the four power distribution rooms, there are two first-level power distribution rooms, two second-level power distribution rooms, and two branch loops. The structure is the same as the first branch loop and the second branch loop respectively. The endpoints of the two branch loops on the side of each first-level power distribution room are connected one-to-one to the two busbars of a switching station in the backbone network. The two secondary power distribution rooms are connected by connecting cables and run in an open loop; the distribution automation device adopts intelligent distributed feeder automation technology; as shown in the figure, the filled switch indicates closing position, and the unfilled switch indicates closing position. The busbars described in this paper are horizontal lines, and the feeder lines are vertical lines; the incoming line refers to the feeder line connecting the upper-level busbar to the current-level busbar, and the outgoing line refers to the feeder line connecting the current-level busbar to the lower-level busbar.

The embodiment of the present invention adopts "switch station feeder" overcurrent protection + "public power distribution room" intelligent distributed DTU device. The scope of realizing distributed feeder automation: between the incoming line switches of the first-level public power distribution room at both ends of the double ring network. The 10kV bus section switch in each public power distribution room does not participate in the rapid self-healing process of power distribution automation. As shown in Figure 4.

The switch station feeder adopts overcurrent protection as the main protection; each bus section of the public power distribution room is equipped with an intelligent distributed DTU device, which completes the position signal, voltage, current, active power, reactive power, power factor, and power of the switchgear. Acquisition and calculation of energy and other data, opening and closing operations of switches, realizing fault identification and isolation of feeder switches and restoration of power supply to non-faulty areas. The device has the functions of line optical difference protection, bus differential protection, self-healing control function, over-current protection, zero-sequence over-current protection, backup protection, and failure protection.

A total of 8 intelligent distributed DTU devices need to be configured in the double-ring network connection of the branch line network of the present invention, and 2 of them are configured in each public power distribution room.

The double-petal backbone network is composed of the first substation 1-1, the second substation 1-2 and the first to fourth switching stations 2-1 to 2-4 and forms two main loops, the two The structure of the main ring is the same as the first main ring and the second main ring respectively, and the first main ring is composed of the same section of busbar of the first substation 1-1 and the first to fourth switching stations 2-1~2 -4, the second main ring is composed of the same bus section of the second substation 1-2 and the second bus section of the first to fourth switching stations 2-1~2-4, the said The bus of the first substation 1-1, the first section of the bus of the first switching station 2-1, the first section of the bus of the second switching station 2-2, the first section of the bus of the third switching station 2-3 and the fourth The first section of busbars of switchyards 2-4 are connected in series through their respective outlet circuit breakers.

Example 1

As shown in Figure 2, the network structure of the backbone network is double petals. The incoming line of each switch station is equipped with optical difference protection, and the busbar is independently equipped with bus differential protection. The dotted line in the figure is the first loop, and the thick solid line is the second loop; The protection range is the line in the box in the figure.

As shown in Figure 3, the fault point 1 occurred on the trunk line between the switch station of the first loop 1 and the switch station of the first loop 2, and the switch connected to the fault line was the trunk line outlet switch of the switch station of the first loop 1 S120 and the main line incoming switch S210 of switch station 2 of the first loop, the switch of S120 of switch station 1, and the switch of S210 of switch station 2, the fault treatment is completed.

Fault point 2 occurs in the feeder line of the switch station of the first loop 2, and the switch connected to the feeder line is K211, so the switch K211 is opened, and the fault treatment is completed.

Fault point 3 occurs at the busbar of the switch station of the first loop 2, and the switches connected to this bus include feeder switches K211 to K216 of the switch station of the first loop 2, main line incoming switch S210 of the switch station of the first loop 2, and the first Loop 1 switch station main line outlet switch S120, so the switches K211 to K216 are opened, the switches S210 and S120 are opened, the local standby automatic switching is blocked, and the fault treatment is completed.

Fault 4 occurred after the opening of fault 3. While the fault was not resolved, fault point 4 was located at the busbar of the first loop 4 switching station. Main line switch incoming line switch S310 and main main line outgoing line switch S320, so the S310 and S320 switches are opened, the K311 to K316 switches are opened, the local standby automatic switching is blocked, and the fault treatment is completed. At this time, the switch station 4 of the first loop detects the loss of voltage of the busbar, and the system starts to prepare for automatic switching on the spot. The switch stations S410 and S420 of the switch station 4 of the first loop trip, and the switch station S400 of the fourth switch station of the first loop closes the tie switch. , the non-faulty area recovers.

Example 2

During normal operation, fault points 1, 2, and 3 are different fault points that occur in three areas respectively. As shown in Figure 5, the incoming line of the first-level power distribution room is faulty, and a ground fault occurs at fault point 1. Outside the scope of distributed feeder automation protection, the DTUs in the distribution rooms of A-1#, A-2#, B-2#, and B-1# will not issue action commands to the switches. The 222 switch overcurrent stage II protection of the switch station A operates, and trips after a 0.3 second delay, and the busbars of the stage II section of the A-1# and A-2# power distribution rooms lose voltage. Distributed feeder automation is logically judged (there is no internal fault signal, and the busbar in the power distribution room loses voltage), and the 202 switch in the A-1# power distribution room is divided. After the opening is successful, the 222 switch in the B-2# power distribution 1#, A-2# power distribution room II section bus to restore power supply.

There is a fault in the line between the first-level power distribution room and the second-level power distribution room, and a ground fault occurs at fault point 2. The distributed feeder automatically detects the fault signal, locates the fault point through logical judgment, and divides it into A-1# power distribution room 222 Switch and switch 202 in A-2# power distribution room (A-2# power distribution room Ⅱ section bus loses power), after the fault is successfully isolated, close the 222 switch in B-2# power distribution room, A-2# power distribution room Ⅱ The segment bus is restored to power. The switchyard feeder overcurrent protection tripped because the operating time was not reached.

The busbar in the power distribution room is faulty, and a ground fault occurs at the fault point 3 (located in the busbar of the second section of the A-1# power distribution room). The distributed feeder automatically detects the fault signal, locates the fault point through logical judgment, and jumps off the A-1# power distribution All incoming and outgoing line switches on the busbars of section II of the room (A-1#, A-2# power distribution room II busbars lose power), after the fault is successfully isolated: close the 222 switch of the B-2# power distribution room, A-2# The power supply of the second section of the bus in the power room is restored; at the same time, the A-1# power distribution room starts 380V low-voltage automatic switching, and the low-voltage load carried by the A-1# power distribution room of the second section of the bus resumes power supply.

Example 3

As shown in Figure 6, it is assumed that when the incoming cable of the 201 switch in the A-1# power distribution room is overhauled, before the maintenance, after manual operation: the 212 switch of the switch station A is in the position; the 201 switch of the A-1# power distribution room In the off position; B-2# power distribution room 212 switch is in the close position.

The incoming line fault of the first-level power distribution room, a ground fault occurs at fault point 1, because the fault point occurs outside the protection range of distributed feeder automation, A-1#, A-2#, B-2#, B-1 # The DTU in the power distribution room cannot detect a fault signal, and the switch in the power distribution room does not operate. The 222 switch overcurrent stage II protection of the switch station A operates, and trips after a delay of 0.3 seconds, and the busbars of the stage II section of the A-1# and A-2# power distribution rooms lose voltage. Distributed feeder automation is logically judged (there is no internal fault signal, and the busbar in the power distribution room loses voltage), and the 202 switch in the A-1# power distribution room is divided. After the opening is successful, the 222 switch in the B-2# power distribution room is closed. 1#, A-2# power distribution room II section bus to restore power supply.

There is a fault in the line between the first-level power distribution room and the second-level power distribution room, and a ground fault occurs at two fault points. The distributed feeder automatically detects the fault signal, locates the fault point through logical judgment, and divides it into A-1# power distribution room 222 switch and 202 switch in A-2# power distribution room (A-2# power distribution room Ⅱ section bus loses power), after the fault is successfully isolated, close the 222 switch in B-2# power distribution room, A-2# power distribution room The power supply of section II busbar is restored.

The busbar in the power distribution room is faulty, and a ground fault occurs at the fault point 3 (located in the busbar of the second section of the A-1# power distribution room). The distributed feeder automatically detects the fault signal, locates the fault point through logical judgment, and jumps off the A-1# power distribution All incoming and outgoing line switches on the busbars of section II of the room (A-1#, A-2# power distribution room II busbars lose power), after the fault is successfully isolated: close the 222 switch of the B-2# power distribution room, A-2# The power supply of the second section of the bus in the power room is restored; at the same time, the A-1# power distribution room starts 380V low-voltage automatic switching, and the low-voltage load carried by the A-1# power distribution room of the second section of the bus resumes power supply.

There is also a bus fault in the power distribution room. A ground fault occurs at fault point 4 (located in the first section of the bus in A-2# power distribution room). The distributed feeder automatically detects the fault signal, locates the fault point through logical judgment, and jumps A-2 # All the incoming and outgoing line switches on the first section of the bus in the power distribution room (the first section of the bus in the A-2# power distribution room is de-energized). After the fault is successfully isolated, the A-2# power distribution The load carried by the busbar of Section I of the electric room shall be restored to power supply.

Claims (10)

1. A quick self-healing method for line faults in a sub-dry distribution network, characterized in that it comprises the following steps: S100: determine the power distribution room or switchyard where the fault point is located according to the DTU fault alarm signal; S200: determine the faulty location Line; S300: Determine the loop where the faulty line is located; S400: Determine the current grid operation status; S500: Determine the switch connected to the faulty line; comprehensively study and judge the self-healing strategy, and select the switch that needs to be opened from the switches connected to the faulty line switch, and open the switch, determine whether it is necessary to close the contact cable switch of the loop, and operate it. 2. A fast self-healing method for line faults in secondary distribution network according to claim 1, characterized in that, during normal operation, the first-level power distribution room of the first loop is connected to the second-level distribution room of the first loop. For line faults between power rooms, the S500 adopts the following steps: at this time, the outgoing line switch of the first-level power distribution room of the first loop and the incoming line switch of the second-level power distribution room of the first loop are connected to the faulty line; Judgment: Open the outgoing line switch of the first-level power distribution room of the first loop; open the incoming line switch of the second-level power distribution room of the first loop; close the contact switch of the first loop. 3. A fast self-healing method for line faults in secondary distribution network according to claim 1, characterized in that, when the first-level power distribution room of the first loop is overhauled, the first-level distribution of the second loop If there is a line fault between the power room and the second-level power distribution room of the second loop, the S500 adopts the following steps: at this time, the outlet switch of the first-level power distribution room of the second loop and the second-level distribution The incoming line switch of the power room is connected to the faulty line; after comprehensive research and judgment, the incoming line switch of the first-level power distribution room of the second loop is opened; the outgoing line switch of the first-level power distribution room of the second loop is opened. The gate; the second loop contact switch is closed. 4. A method for rapid self-healing of line faults in secondary distribution network according to claim 2, characterized in that, the method for rapid self-healing of line faults in secondary distribution network applies a composite grid structure based on reliable power supply, It includes a backbone network and a branch network connected to each other, and the backbone network is a double-petal backbone network. 5. A fast self-healing method for line faults in a secondary distribution network according to claim 4, wherein the branch line network is a double-ring network consisting of four power distribution rooms and containing two branch loops , the number of first-level power distribution rooms in the four power distribution rooms is two, the number of second-level power distribution rooms is two, and the structures of the two branch loops are the same, namely the first branch loop and the second branch loop , the ends of the two branch loops on the side of each primary power distribution room are connected one-to-one with the two busbars of a switching station in the backbone network, and the two secondary power distribution rooms are connected and opened by connecting cables. ring run. 6. A fast self-healing method for line faults in secondary distribution network according to claim 5, characterized in that the double-petal backbone network is composed of the first substation, the second substation and the first to fourth switching stations And form two main loops. 7. A fast self-healing method for line faults in a secondary distribution network according to claim 6, wherein the two main loops have the same structure and are respectively the first main loop and the second main loop . 8. A rapid self-healing method for line faults in a secondary distribution network, characterized in that it comprises the following steps: S100: According to the DTU fault alarm signal, determine the power distribution room or switch station where the fault point is located; S200: Determine the faulty line; S300: Determine the loop where the faulty line is located; S400: Determine the current grid operation state; S500: Determine the switch connected to the faulty line; comprehensively study and judge the self-healing strategy, select the switch that needs to be opened from the switches connected to the faulty line, and open the switch, and determine whether the contact cable switch of the loop needs to be closed. and operate; When the feeder line of one of the switching stations in the first ring circuit fails, the S500 adopts the following steps: at this time, the feeder line outlet switch of the first ring switching station is connected to the faulty line; The feeder line switch of the first ring circuit switch station is opened; the switch station with double petal operation, the contact cable switch is in the closed state, and no processing is performed. 9. A rapid self-healing method for line faults in a sub-dry distribution network, comprising the following steps: S100: According to the DTU fault alarm signal, determine the power distribution room or switch station where the fault point is located; S200: Determine the faulty line; S300: Determine the loop where the faulty line is located; S400: Determine the current grid operation state; S500: Determine the switch connected to the faulty line; comprehensively study and judge the self-healing strategy, select the switch that needs to be opened from the switches connected to the faulty line, and open the switch, and determine whether the contact cable switch of the loop needs to be closed. and operate; When the incoming line of the first-level power distribution room of the first loop is faulty during normal operation, the S500 adopts the following steps: at this time, only the incoming line switch of the first-level power distribution room of the first loop is connected to the faulty line, and the switch Opening operation; the first loop contact cable switch is closed. 10. A rapid self-healing method for line faults in a secondary distribution network, comprising the following steps: S100: According to the DTU fault alarm signal, determine the power distribution room or switch station where the fault point is located; S200: Determine the faulty line; S300: Determine the loop where the faulty line is located; S400: Determine the current grid operation state; S500: Determine the switch connected to the faulty line; comprehensively study and judge the self-healing strategy, select the switch that needs to be opened from the switches connected to the faulty line, and open the switch, and determine whether the contact cable switch of the loop needs to be closed. and operate; When the incoming line of the first-level power distribution room of the first loop is overhauled, and the incoming line of the first-level power distribution room of the second loop fails, the S500 adopts the following steps: At this time, only the first-level power distribution of the second loop The incoming line switch of the second loop is connected to the incoming line of the first-level power distribution room of the second loop; through comprehensive research and judgment, the above-mentioned second loop first-level power distribution room incoming switch is opened; the second loop contact switch is closed .

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