A power distribution network ring main unit switch dead zone troubleshooting method

Abstract

The application discloses a kind of distribution network ring main unit switch dead zone troubleshooting methods, when the fault occurs between the incoming line switch and current transformer of certain ring main unit in distribution network, first, the outgoing line switch protection of the substation acts and trips, the line loses power, then the fault occurrence area is judged, and the fault area is isolated, and according to the line topological structure before and after the fault occurrence area, respectively, the outgoing line switch of substation is constructed to the front link structure and rear link structure of fault area, then respectively set the tripping condition and closing condition to switch in line, switch is tripped and closed operation accordingly, complete the troubleshooting of distribution network ring main unit switch dead zone, and restore the load power supply between the front switch of fault area and the rear switch of fault area.The technical scheme of the application is based on the topological structure of fault occurrence area, sets the tripping condition and closing condition to the front and rear switches of fault occurrence area to complete the isolation and power supply recovery of fault area, which can quickly and effectively isolate fault point.

Description

Technical Field

[0001] This invention belongs to the field of power distribution networks, and specifically relates to a method for troubleshooting dead zone faults in power distribution network ring main unit switches. Background Technology

[0002] Feeder automation (FA) is the core function of distribution automation systems. It integrates computer, information, and communication technologies. Traditional FAs automatically locate faults, isolate faults, and restore power to non-faulty areas when a fault occurs in the distribution network, thus improving the reliability of the distribution network. Feeder automation is mainly divided into two types: centralized and local. Centralized FA is further divided into two types: fully automatic and semi-automatic. Local FA is divided into four types: recloser-type feeder automation, intelligent distributed feeder automation, decomposed watchdog type, and relay protection type.

[0003] With the development of the national economy and the progress of science and technology, the cable coverage rate of urban power distribution networks is showing an increasing trend. Due to their economy and reliability, ring main units are occupying an increasingly larger proportion in power distribution networks. However, if a permanent fault occurs between the ring main unit switch and the current transformer, it will lead to incorrect fault location in the feeder automation system, causing repeated power outages in non-faulty areas, or even expanding the scope of power outages, seriously affecting economic development and residents' lives. Therefore, a fault troubleshooting method is needed when a permanent fault occurs between the ring main unit and the current transformer in the power distribution network. Summary of the Invention

[0004] To address the aforementioned problems, the present invention aims to provide a method for eliminating dead zone faults in distribution network ring main unit switches. This method can reduce the adverse effects of dead zone faults in distribution network ring main unit switches, avoid repeated power outages in the upstream section of the fault area, prevent the fault point from shifting to normal lines and causing the power outage area to expand, and improve the reliability of power supply in the distribution network.

[0005] The specific technical solution for achieving the objective of this invention is as follows:

[0006] A method for troubleshooting dead-zone faults in distribution network ring main unit switches includes the following steps:

[0007] Step 1: When a fault occurs between the incoming switch and the current transformer of a ring network cabinet in the distribution network, the protection of the outgoing switch of the substation trips, and the line loses power.

[0008] Step 2: Determine the area where the fault occurred and isolate the fault area;

[0009] Step 3: Based on the line topology before and after the fault location, construct the link structure from the substation outgoing switch to the front section of the fault area and the link structure from the substation outgoing switch to the back section of the fault area, respectively.

[0010] Step 4: Set tripping conditions for the switches in the front and rear sections of the fault area, and close the outgoing switches of the substation where the fault area is located and the interconnection switches between the substations in the rear section of the fault area. Based on the tripping status of the switches in the front and rear sections of the fault area, complete the isolation of the fault between the incoming switches of the ring main unit and the current transformer.

[0011] Step 5: Set closing conditions for the switches in the front and rear sections of the fault area. The switches in the front and rear sections of the fault area will close or open according to the closing conditions to complete the load power supply between the switches in the front and rear sections of the fault area, and complete the elimination of the dead zone fault of the distribution network ring network cabinet switches.

[0012] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0013] (1) The technical solution of the present invention is based on the topology of the fault occurrence area. It sets tripping and closing conditions for the switches before and after the fault occurrence area to complete the isolation of the fault area and power supply restoration, which can quickly and effectively isolate the fault point.

[0014] (2) The technical solution of the present invention can effectively reduce repeated power outages upstream of the fault area, avoid the transfer of four-wheel drive faults, avoid the expansion of the power outage range, and improve the reliability of the power supply line. Attached Figure Description

[0015] Figure 1 This is a flowchart of the method for troubleshooting dead zone faults in distribution network ring main unit switches according to the present invention.

[0016] Figures 2 to 7 This is a schematic diagram illustrating the troubleshooting process for dead zone faults in a distribution network ring main unit switch in an embodiment of the present invention. Detailed Implementation

[0017] A method for troubleshooting dead-zone faults in distribution network ring main unit switches includes the following steps:

[0018] Step 1: When a fault occurs between the incoming switch and the current transformer of a ring network cabinet in the distribution network, the protection of the outgoing switch of the substation trips, and the line loses power.

[0019] Step 2: Determine the area where the fault occurred and isolate the fault area, specifically as follows:

[0020] The fault area is determined based on the protection information of each switch in the distribution network and the protection information of the outgoing switches of the substations on both sides of the distribution network.

[0021] Based on the fault area, disconnect the switches on both sides of the fault area to isolate the fault area.

[0022] Step 3: Based on the line topology before and after the fault location, construct the link structure from the substation outgoing switch to the front section of the fault area and the link structure from the substation outgoing switch to the rear section of the fault area, specifically as follows:

[0023] The front section of the fault area refers to the area with a shorter power supply radius in the power supply areas on both sides of the fault area, while the rear section of the fault area refers to the area with a longer power supply radius in the power supply areas on both sides of the fault area.

[0024] The upstream link structure of the fault area includes the upstream switch of the fault area to the outgoing switch of the upstream substation.

[0025] The link structure downstream of the fault area includes the downstream switch of the fault area to the substation outgoing switch on the non-fault side of the downstream area.

[0026] Step 4: Set tripping conditions for the switches in the upstream and downstream sections of the fault area, and close the outgoing switches of the substation where the fault area is located, as well as the interconnection switches between substations in the downstream section of the fault area. Based on the tripping status of the switches in the upstream and downstream sections of the fault area, complete the fault isolation between the incoming switches and current transformers of the ring main unit. Specifically:

[0027] Step 4-1: Set tripping conditions for the upstream switch of the switch in the faulty area:

[0028] (1) Switch protection activated;

[0029] (2) Power is restored after the switch loses power;

[0030] When conditions (1) and (2) are met simultaneously, the upstream switch of the switch in the fault area trips.

[0031] Step 4-2: Set the tripping condition for the upstream switch of the switch downstream of the fault area: switch protection activated;

[0032] When the conditions are met, the upstream switch of the switch in the downstream section of the fault area trips.

[0033] When the outgoing switch of the substation where the fault area is located and the interconnection switch between the substations in the downstream section of the fault area are closed, the upstream three-remote switch of the switch in the upstream section of the fault area meets the tripping conditions and trips instantaneously. At this time, the protection of the outgoing switch of the substation on this side and the distribution network line switch is reset, completing the isolation of the permanent fault between the incoming switch of the distribution network ring network cabinet and the current transformer, and at the same time completing the power supply of the load in the upstream section of the fault area.

[0034] The upstream switch of the switch in the fault area does not meet the trip logic command, and the switch remains closed.

[0035] Step 5: Set closing conditions for the switches in the upstream and downstream sections of the fault area. The switches in the upstream and downstream sections of the fault area will close or open according to the closing conditions, completing the load power supply between the upstream and downstream switches of the fault area, and completing the elimination of the dead zone fault of the distribution network ring network cabinet switches. Specifically:

[0036] Step 5-1: Issue a closing logic command to the upstream switch of the faulty area, specifically:

[0037] (1) The switch protection is not activated;

[0038] (2) Switches in the downstream section of the fault area are in operation;

[0039] (3) The protection of the three-remote switch above the switch of the fault area is activated.

[0040] Step 5-2: Issue a closing logic command to the downstream switch of the fault area, specifically:

[0041] (1) The switch protection is not activated;

[0042] (2) The switch above the faulty area's upstream switch is in position;

[0043] (3) The protection of the front-end switch in the fault area is activated.

[0044] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0045] Example

[0046] The power distribution network structure in this embodiment is as follows: Figure 2 As shown, the system includes substation outgoing line switches Q1 and Q2, ring main units H1, H2, H3, and H4, ring main units with remote control functions K1, K2, K3, K4, K5, K6, K7, and K8, load switches L1, L2, L3, and L4, and switch K5 is the connecting switch between lines Q1 and Q2. Solid lines represent the closed position of the switch, and hollow lines represent the open position of the switch.

[0047] A method for troubleshooting dead-zone faults in distribution network ring main unit switches includes the following steps:

[0048] Step 1, as follows Figure 3 As shown, when a fault occurs between the incoming switch K3 and the current transformer CT3 of a ring network cabinet in the distribution network, the protection of the outgoing switch Q1 of the substation trips, and the Q1 line loses power.

[0049] Step 2: Determine the area where the fault occurred and isolate the fault area, specifically as follows:

[0050] Based on the protection information of the substation outgoing switch Q1 and the line switches K1, K2, and K3, the fault area is determined to be between switch K3 and switch K4. At this time, control switches K3 and K4 to trip. Figure 4 As shown;

[0051] Step 3: Based on the line topology before and after the fault location, construct the link structure from the substation outgoing switch to the front section of the fault area and the link structure from the substation outgoing switch to the rear section of the fault area, specifically as follows:

[0052] The front section of the fault area refers to the area with a shorter power supply radius in the power supply areas on both sides of the fault area, while the rear section of the fault area refers to the area with a longer power supply radius in the power supply areas on both sides of the fault area.

[0053] The upstream link structure of the fault area includes the upstream switch of the fault area to the outgoing switch of the upstream substation.

[0054] The link structure downstream of the fault area includes the downstream switch of the fault area to the substation outgoing switch on the non-fault side of the downstream area.

[0055] Specifically, in this embodiment, the link structure from the substation outgoing switch to the fault area is: the link structure of substation switch Q1, switch K1, switch K2, and switch K3, where switch K2 is the upstream remote control switch of switch K3.

[0056] The link structure from the substation outgoing switch to the fault area is as follows: substation switch Q2, switch K8, switch K7, switch K6, and switch K5.

[0057] Step 4: Set tripping conditions for the switches in the upstream and downstream sections of the fault area, and close the outgoing switches of the substation where the fault area is located, as well as the interconnection switches between substations in the downstream section of the fault area. Based on the tripping status of the switches in the upstream and downstream sections of the fault area, complete the fault isolation between the incoming switches and current transformers of the ring main unit. Specifically:

[0058] Step 4-1: For the upstream switch of the faulty area, in this embodiment, a tripping condition is set for switch K2:

[0059] (1) Switch protection activated;

[0060] (2) Power is restored after the switch loses power;

[0061] When conditions (1) and (2) are met simultaneously, the upstream switch of the switch in the fault area trips.

[0062] Step 4-2: For the upstream switch of the switch in the fault area, in this embodiment, the tripping condition is set for switch K5: switch protection is activated;

[0063] When the conditions are met, the upstream switch of the switch in the downstream section of the fault area trips.

[0064] When the outgoing switch of the substation where the fault area is located and the interconnection switch between the substations in the downstream section of the fault area are closed, the upstream three-remote switch of the switch in the upstream section of the fault area meets the tripping conditions and trips instantaneously. At this time, the protection of the outgoing switch of the substation on this side and the distribution network line switch is reset, completing the isolation of the permanent fault between the incoming switch of the distribution network ring network cabinet and the current transformer, and at the same time completing the power supply of the load in the upstream section of the fault area.

[0065] The upstream switch of the switch in the fault area does not meet the trip logic command, and the switch remains closed.

[0066] Combination Figure 5 and Figure 6 In this embodiment, after switch Q1 and switch K5 are closed, the upstream three-remote switch of the switch in the fault area, namely K2, meets the requirements of power restoration after power loss and protection activation, and switch K2 trips instantly.

[0067] Switches Q1 and K1 are reset to their protection settings, completing the isolation of the permanent fault between current transformer CT3 and switch K3, ensuring reliable power supply to the upstream load. Switch K5 does not meet the trip logic command and remains closed.

[0068] Step 5: Set closing conditions for the switches in the upstream and downstream sections of the fault area. The switches in the upstream and downstream sections of the fault area will close or open according to the closing conditions, completing the load power supply between the upstream and downstream switches of the fault area, and completing the elimination of the dead zone fault of the distribution network ring network cabinet switches. Specifically:

[0069] Step 5-1: Issue a closing logic command to the upstream switch of the fault area, specifically switch K3 in this embodiment, as follows:

[0070] (1) Switch K3 protection is not activated;

[0071] (2) Switch K4 in the downstream section of the fault area is in position;

[0072] (3) The protection of the three-remote switch K5, which is one level above the switch of the fault area downstream, is activated.

[0073] Step 5-2: Issue a closing logic command to the downstream switch of the fault area, specifically switch K4 in this embodiment, as follows:

[0074] (1) Switch K4 protection is not activated;

[0075] (2) The upstream switch K2 of the switch in the fault area;

[0076] (3) The protection of switch K3 in the front section of the fault area is activated.

[0077] like Figure 7 Switch K4 meets the closing logic and completes the closing, restoring power supply to load L2. Switch K3 does not meet the closing logic and remains open. This completes the load power supply between the upstream and downstream switches of the faulty area, thus eliminating the dead zone fault in the distribution network ring main unit.

[0078] The above embodiments illustrate and describe the basic principles and main features of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the present invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed.

Claims

1. A power distribution network ring main unit switch dead zone troubleshooting method, characterized in that, The method comprises the following steps: Step 1, when a fault occurs between an incoming line switch and a current transformer of a ring network cabinet in a power distribution network, an outgoing line switch protection of a substation is tripped, and the line loses power; Step 2, a fault area is determined, and the fault area is isolated: The fault area is determined according to protection information of each switch in the power distribution network and protection information of outgoing line switches of substations on both sides of the power distribution network; According to the fault area, the switches on both sides of the fault area are tripped to complete isolation of the fault area; Step 3, according to a line topology structure before and after the fault area, a link structure from an outgoing line switch of a substation to a front section of the fault area and a link structure from the outgoing line switch of the substation to a rear section of the fault area are respectively constructed: The front section of the fault area is a section with a shorter power supply radius in power supply sections on both sides of the fault area, and the rear section of the fault area is a section with a longer power supply radius in the power supply sections on both sides of the fault area; The link structure of the front section of the fault area comprises switches in the front section of the fault area to an outgoing line switch of a front section substation; The link structure of the rear section of the fault area comprises switches in the rear section of the fault area to an outgoing line switch of a rear section substation on a non-fault side; Step 4, a tripping condition is set for the switches in the front section and the rear section of the fault area, and a tie switch between the outgoing line switch of the substation where the fault area is located and a substation in the rear section of the fault area is closed, and according to tripping of the switches in the front section and the rear section of the fault area, isolation of the fault between the incoming line switch and the current transformer of the ring network cabinet is completed: Step 4-1, a tripping condition is set for a switch of a next level of the switch in the front section of the fault area: Condition (1): switch protection is started; Condition (2): the switch loses power and then regains power; When conditions (1) and (2) are met simultaneously, the switch of the next level of the switch in the front section of the fault area is tripped; Step 4-2, a tripping condition is set for a switch of a next level of the switch in the rear section of the fault area: switch protection is started; When the condition is met, the switch of the next level of the switch in the rear section of the fault area is tripped; After the outgoing line switch of the substation where the fault area is located and the tie switch between the substations in the rear section of the fault area are closed, the switch of the next level of the switch in the front section of the fault area meets the tripping condition and is tripped instantaneously, at this time, the outgoing line switch of the substation on this side and the switch protection of the power distribution network line are reset, and the isolation of the permanent fault between the incoming line switch and the current transformer of the ring network cabinet in the power distribution network is completed, and the power supply of the load in the front section of the fault area is completed; The switch of the next level of the switch in the rear section of the fault area does not meet the tripping logic command, and the switch remains closed; Step 5, a closing condition is set for the switches in the front section and the rear section of the fault area, and the switches in the front section and the rear section of the fault area are closed or tripped according to the closing condition, the load power supply between the switch in the front section of the fault area and the switch in the rear section of the fault area is completed, and the exclusion of the dead zone fault of the ring network cabinet in the power distribution network is completed.

2. The power distribution network ring main unit switch dead zone troubleshooting method according to claim 1, characterized in that, In step 5, the closing condition set for the switches in the front section and the rear section of the fault area is specifically: Step 5-1, a closing logic command is issued to the switch in the front section of the fault area; Step 5-2, a closing logic command is issued to the switch in the rear section of the fault area.

3. The power distribution network ring main unit switch dead zone troubleshooting method according to claim 2, characterized in that, In step 5-1, the closing logic command issued to the switch in the front section of the fault area is specifically: (1) switch protection is not started; (2) the switch in the rear section of the fault area is tripped; (3) the upper level three-remote switch protection of the switch at the rear section of the fault area is started.

4. The power distribution network ring main unit switch dead zone troubleshooting method according to claim 2, characterized in that, The step 5-2 comprises the following steps: (1) the switch protection is not started; (2) the upper level switch of the switch at the front section of the fault area is in the split position; (3) the switch protection of the switch at the front section of the fault area is started.

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