Electrified switching method for bus operation modes of distributed substation

Abstract

The invention relates to a live-line switching method for a bus operation mode of a distributed substation, and belongs to the technical field of power transformation and distribution system operation. According to the technical scheme, when a switch of a 10kV bus coupler cabinet of a 110kV transformer substation is located at a switching-on position, and a 10kV bus coupler cabinet trolley and a bus coupler lifting cabinet trolley are both located at operating positions, a first power supply incoming line and a switching-on locking loop of a bus coupler cabinet and a second power supply incoming line and a bus coupler cabinet of each distributed transformer substation are shielded, and three-throw three-loop closing is achieved; therefore, live-line switching of the bus operation modes of the distributed substations is realized. The system has the advantages that the risk of substation circulation caused by manual misoperation is fundamentally avoided, the stability and accuracy of signal transmission are effectively guaranteed by adopting a multi-node signal transmission mode, potential safety hazards caused by signal problems are reduced, power failure is not needed when operation modes of all distributed substations are switched, and the system is safe and reliable. The power failure time and the power failure frequency are reduced, the power supply reliability is improved, and normal power utilization is effectively guaranteed.

Description

Technical Field

[0001] The present invention relates to a method for live switching of busbar operation modes of distributed substations, which is suitable for solving the problem of obstruction of maintenance and repair progress of electrical equipment caused by the three-in-two operation mode of substations, and the problem of large-scale power outage caused by reverse incoming lines of substations. Through precise shielding of the dual power incoming lines and the closing and locking circuit of the busbar cabinet of each distributed substation under specific conditions, the three-in-three-closed operation mode is allowed, and the reliability of low-voltage signal transmission is guaranteed by means of a multi-node signal transmission mode, so as to realize live switching of busbar operation modes of each distributed substation. The method belongs to the technical field of operation of power transformation and distribution systems. Background Art

[0002] With the continuous growth of electricity demand and the increasing complexity of the power system, it is particularly important to ensure the safe and stable operation of the power system. In the existing operation mode of the power system, the No. 1 power supply line and busbar cabinet and the No. 2 power supply line and busbar cabinet switches of each distributed 10kV substation are generally equipped with electrical interlocks, and adopt a three-throw-two operation mode. There are many serious drawbacks in the existing operation mode: this means that when switching the operation mode of each distributed substation, it is necessary to shut down one of the busbars of the substation before the operation can be carried out. This operation mode is not only cumbersome to operate, but also causes some loads to lose power supply during the power outage, affecting the continuity and reliability of power supply. On the one hand, this operation mode greatly affects the normal maintenance and repair work process of electrical equipment, making it difficult to proceed smoothly; on the other hand, the large-scale power outage caused by the reverse line has brought a heavy blow to the production efficiency of power users, seriously restricting the normal production and development of power users. Summary of the invention

[0003] The purpose of the present invention is to provide a method for switching the busbar operating mode of a distributed substation under power conditions, which fundamentally avoids the danger of circulating current in the substation caused by human error. The multi-node signal transmission method effectively ensures the stability and accuracy of signal transmission and reduces the safety hazards caused by signal problems. Each distributed substation does not need to shut down when switching the operating mode, which reduces the power outage time and the number of power outages, improves the power supply reliability, effectively ensures normal power use, and solves the above-mentioned technical problems existing in the background technology.

[0004] The technical solution of the present invention is as follows: A method for switching the busbar operation mode of a distributed substation under power conditions comprises the following steps: Collect signals in the 10kV busbar cabinet and busbar lifting cabinet of the 110kV substation, and monitor the operating status of the 10kV busbar cabinet circuit breaker, 10kV busbar cabinet trolley and busbar lifting cabinet trolley in real time; When any of the 10kV busbar circuit breaker, 10kV busbar trolley and busbar lifting trolley of the 110kV substation is not in the closed or running position, the electrical interlocking of the No. 1 power supply line and busbar and No. 2 power supply line and busbar of each distributed substation is effective; When the switch of the 10kV busbar cabinet of the 110kV substation is in the closed position, and the 10kV busbar cabinet trolley and the busbar lifting cabinet trolley are both in the operating position, the closing and locking circuits of the No. 1 power supply incoming line and busbar cabinet and the No. 2 power supply incoming line and busbar cabinet of each distributed substation are shielded, realizing three-drop and three-closing loops, so that the busbar operation mode of each distributed substation can be switched under power.

[0005] The position signals of the 10kV busbar circuit breaker, 10kV busbar trolley and busbar lifting trolley of the 110kV substation are connected in series with the shielded wire, and multi-node signal transmission is adopted; at the same time, considering the distance factor of each distributed substation, a multi-node signal transmission method is adopted to ensure the accuracy and stability of the signal.

[0006] The present invention can comprehensively transform the existing No. 1 power supply incoming line and bus coupling cabinet and No. 2 power supply incoming line and bus coupling cabinet of each distributed substation into a three-on-two operation mode and a three-on-three-closed-loop operation.

[0007] If the 10kV bus tie switch of a 110kV substation is in the open state, that is, the separate operation state, the three-on-three operation of each distributed substation will produce a large circulating current, which is dangerous. Therefore, the closing and locking circuits of each distributed substation cannot be directly shielded with short-circuit wires. The position signals of the 10kV bus tie cabinet circuit breaker, the 10kV bus tie cabinet trolley and the bus tie lifting cabinet trolley of the 110kV substation need to be connected in series with the shielding wire to ensure that only when the 10kV bus tie cabinet circuit breaker of the 110kV substation is in the closed position and the 10kV bus tie cabinet trolley and the bus tie lifting cabinet trolley are in the operating position, each distributed substation is allowed to operate in the three-on-three operation mode to realize the live switching of the busbar operation mode.

[0008] The positive effects of the present invention are: fundamentally avoiding the danger of substation circulation caused by human error operation, adopting a multi-node signal transmission method, effectively ensuring the stability and accuracy of signal transmission, reducing the potential safety hazards caused by signal problems, and each distributed substation does not need to shut down when switching the operation mode, reducing the power outage time and the number of power outages, improving the reliability of power supply, and effectively ensuring normal power consumption. The present invention enables each distributed substation to flexibly switch the operation mode according to the actual load conditions and the power grid operation requirements, improves the system's adaptability and ability to respond to emergencies, and can switch the busbar operation mode of each distributed substation without power outage, creating favorable conditions for the power supply system to carry out equipment maintenance and overhaul in a timely manner, and can arrange maintenance and overhaul plans more reasonably, improving the efficiency and quality of maintenance and overhaul work. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 This is a schematic diagram of the closing and locking principle of a 10kV busbar in a substation according to an embodiment of the present invention; Figure 2 It is a schematic diagram of the power supply incoming line cabinet No. 1 and the power supply incoming line cabinet No. 2 of the substation according to the embodiment of the present invention; Figure 3 This is a schematic diagram of the closing state of the 10kV busbar circuit breaker in a 110kV substation according to an embodiment of the present invention; Figure 4 This is a schematic diagram of a 10kV busbar circuit breaker trolley in a 110kV substation according to an embodiment of the present invention; Figure 5 This is a schematic diagram of a 110kV substation busbar lifting cabinet according to an embodiment of the present invention; Figure 6 This is a diagram of a substation and the transformation of each substation according to an embodiment of the present invention; Figure 7 This is the schematic diagram of the 10kV busbar cabinet after the closing and locking transformation of the substation in the embodiment of the present invention. DETAILED DESCRIPTION

[0010] The present invention will be further described in detail below by the following examples.

[0011] The existing technology power supply system of a certain enterprise consists of a 110kV substation and No. 1-5 distributed 10kV substations. No. 1-5 distributed 10kV substations all have No. 1 power incoming line and bus coupling cabinet and No. 2 power incoming line and bus coupling cabinet. It is the most common substation primary system and three-throw two-interlocking operation mode. The following is an explanation based on its schematic diagram as an example.

[0012] like Figure 1 As shown, Y1 is the closing locking electromagnet, and the auxiliary switch S2 of Y1 is connected in series with the closing release Y3 in the closing circuit. Only when Y1 is energized and the normally open point S2 of its auxiliary switch is closed, the closing release Y3 can be energized and act (other conditions are met at the same time) to complete the closing of the 10kV busbar circuit breaker. Figure 1 As shown, in the X3:3 to X3:9 circuit, Y1 must meet the following three conditions at the same time for it to be energized: ① At least one of the incoming line 1 or incoming line 2 circuit breakers is in the open position.

[0013] like Figure 2 As shown in the figure, S3 is the auxiliary switch of the circuit breaker of the power supply line 1 cabinet or the power supply line 2 cabinet. When the circuit breaker of the power supply line 1 cabinet or the power supply line 2 cabinet is in the open position, the normally closed point S3 in the X5:9 to X5:10 circuit is in the closed state, so that Figure 1 , X3:16 to X3:18 or X3:17 to X3:19 passage.

[0014] ② The main coupling lifting cabinet trolley is in the running position, that is, Figure 1 Passages X5:1 and X5:2 of the central mother coupling lifting cabinet.

[0015] ③10kV busbar trolley is in the running position, that is, Figure 1 The auxiliary switch S9 of the trolley running position of the 10kV busbar cabinet is closed.

[0016] From the above, it can be seen that in the three cabinets of the No. 1 power supply incoming line and bus coupling cabinet and the No. 2 power supply incoming line and bus coupling cabinet of the substation, the normally closed points of the circuit breaker auxiliary switches of the two cabinets are connected in parallel and then connected in series in the closing lock circuit of the third cabinet. When both circuit breakers are in the closing position, the third circuit breaker cannot be closed. When one of the two circuit breakers is in the opening position and the other is in the closing position, the third circuit breaker can be closed, thereby realizing the three-throw two-interlocking operation mode.

[0017] In an embodiment, the present invention provides a method for switching the operation mode of a substation busbar under power supply, and the specific steps are as follows: Take the normally open point S3 of the auxiliary switch of the 10kV busbar circuit breaker of the 110kV substation ( Figure 3 )、110kV substation 10kV busbar cabinet trolley operation position auxiliary switch S9 ( Figure 4 )、110kV substation 10kV busbar lifting cabinet trolley operation position auxiliary switch S9 ( Figure 5 ), connect the three auxiliary contacts in series, and provide 24-hour uninterrupted power supply through the DC system of Substation No. 1, with contactor 1KM operation ( Figure 6 ). The 1KM contactor has 4 normally open auxiliary switches, of which 3 normally open auxiliary switches are respectively connected to the 3 closing and locking circuits of the No. 1 power supply line and bus coupling cabinet and the No. 2 power supply line and bus coupling cabinet of the No. 1 substation. Figure 7 For example, connect the 1KM1 normally open auxiliary switch between X3:16 and X3:18, forming a parallel relationship with the incoming line 1 cabinet and the incoming line 2 cabinet, accurately shielding the closing and locking circuit, realizing three-throw three-close loop, so that the busbar operation mode of each distributed substation can be switched with power. Another normally open auxiliary switch of the 1KM contactor provides 24-hour uninterrupted power supply through the DC system of the No. 2 substation, driving the contactor 2KM to operate ( Figure 6 ).

[0018] Contactor 2KM has 4 normally open auxiliary switches, 3 of which are respectively connected to the 3 closing and locking circuits of No. 1 power supply line and bus coupling cabinet and No. 2 power supply line and bus coupling cabinet of No. 2 substation ( Figure 7 ). 1 normally open auxiliary switch provides 24-hour uninterrupted power supply through the DC system of Substation No. 3, driving the contactor 3KM operation ( Figure 6 ). The same goes for substations 1-5.

Claims

1. A method for switching the busbar operation mode of a distributed substation under power supply, characterized in that Here are the steps: Collect signals in the 10kV busbar cabinet and busbar lifting cabinet of the 110kV substation, and monitor the operating status of the 10kV busbar cabinet circuit breaker, 10kV busbar cabinet trolley and busbar lifting cabinet trolley in real time; When any of the 10kV busbar circuit breaker, 10kV busbar trolley and busbar lifting trolley of the 110kV substation is not in the closed or running position, the electrical interlocking of the No. 1 power supply line and busbar and No. 2 power supply line and busbar of each distributed substation is effective; When the switch of the 10kV busbar cabinet of the 110kV substation is in the closed position, and the 10kV busbar cabinet trolley and the busbar lifting cabinet trolley are both in the operating position, the closing and locking circuits of the No. 1 power supply incoming line and busbar cabinet and the No. 2 power supply incoming line and busbar cabinet of each distributed substation are shielded, realizing three-drop and three-closing loops, so that the busbar operation mode of each distributed substation can be switched under power.

2. A method for switching the busbar operation mode of a distributed substation under power supply according to claim 1, characterized in that: The position signals of the 10kV busbar circuit breaker, 10kV busbar trolley and busbar lifting trolley of the 110kV substation are connected in series with the shielded wire, and multi-node signal transmission is adopted.

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