Insulation monitoring method for dual-transformer power supply system

Abstract

A method for insulation monitoring a dual-transformer power supply system comprises two insulation monitoring systems used in conjunction. Under normal circumstances, when the bus coupling cabinet is disconnected, the 1# insulation monitoring device and the 2# insulation monitoring device operate independently. When the bus coupling cabinet is closed, the 2# insulation monitoring device stops operating and the 1# insulation monitoring device operates, with the monitoring range being the circuit between the 1# transformer and the 2# transformer. This method solves the problem that the current dual-transformer three-in-two-circuit insulation monitoring system cannot monitor in real time and is subject to interference. The 1# and 2# insulation monitoring devices of the present invention communicate in real time, monitor and eliminate faults in real time, and improve fault troubleshooting efficiency.

Description

Technical Field

[0001] The present invention relates to the field of electronic information, and in particular to an insulation monitoring method for a dual-transformer power supply system. Background Art

[0002] With the continuous advancement of my country's power grid industry, the safe operation of power supply systems faces significant challenges. Dual-transformer power supply systems not only ensure safe operation but also ensure that their functional quality and power supply are consistent with each other. Therefore, dual-transformer power supply systems are widely used. Dual-transformer power supply systems utilize a three-in-two circuit for incoming lines, meaning that only two of the three cabinets can be combined. These three cabinets include: Line Incoming Cabinet 1#, Line Incoming Cabinet 2#, and Bus Tie Cabinet 3#. Under normal circumstances, when two power sources are simultaneously supplied, Line Incoming Cabinet 1# and Line Incoming Cabinet 2# each carry their own loads, and the Bus Tie Cabinet 3# is in the open state. If either Line Incoming Cabinet 1# or Line Incoming Cabinet 2# loses power, the Bus Tie Cabinet automatically switches on, with the other transformer simultaneously carrying the loads on both sides to ensure power to users. When power is restored on the previously outage side, the Bus Tie Cabinet automatically disconnects and returns to its original standby state. This dual-transformer three-in-two circuit provides emergency power supply. However, the existing insulation monitoring system can only be used for one set of transformer outgoing lines. When applied to a three-in-two circuit with two incoming transformers, the injected signals will interfere with each other, making real-time monitoring impossible.

[0003] In order to solve the above problems, a Chinese patent application with publication number CN103595055B discloses a control method for switching the operating states of two transformers in a dual-transformer system. By controlling the first high-voltage circuit breaker C1, the second high-voltage circuit breaker C2, the first low-voltage circuit breaker 1DL, the second low-voltage circuit breaker 2DL and the third low-voltage circuit breaker 3DL of the dual-transformer power supply system in the open and closed states, the dual-transformer power supply system is controlled to switch between the individual operating states of T1 and T2, and according to the state monitoring of the dual-transformer power supply system, the dual-transformer power supply system is adjusted so that it can always be in the most economical operating state, thereby achieving the purpose of energy saving. The control method for switching the operating states of two transformers in a dual-transformer system of the present invention has the advantages of being able to enable the dual-transformer power supply system to operate in the most energy-saving operating mode after power is supplied, being simple and easy to implement and being able to achieve the purpose of energy saving.

[0004] For example, Chinese patent publication number CN107728512B discloses an intelligent device with intelligent monitoring and switchable dual transformers, comprising a substation and a sensing module. The sensing module is electrically connected to a data acquisition module, which is electrically connected to a data comparison module, which is electrically connected to a wireless information transmission module, which is electrically connected to a wireless information receiving module. This intelligent device with intelligent monitoring and switchable dual transformers achieves the effect of sensing and remotely transmitting the operating temperatures of the first, second, and Nth transformers within the execution module. The data sensed by the sensing module is processed by the data acquisition and comparison modules, then remotely transmitted via the wireless information transmission and wireless information receiving modules to a central processing unit for data processing. This effectively solves the problem of transformer equipment in remote substations being difficult to monitor during extreme weather.

[0005] Currently, these patents still have certain deficiencies in actual operation: the first patent enables a dual-transformer power supply system to operate in an optimal energy-saving mode after power is delivered, while the second patent addresses the difficulty of monitoring transformer equipment in remote substations during extreme weather. While both existing technologies can monitor dual-transformer power supply systems, signal interference can affect the accuracy and stability of system monitoring, leaving room for improvement. Summary of the Invention

[0006] In view of the deficiencies in the prior art, the present invention provides an insulation monitoring method for a dual-transformer power supply system to solve the above problems.

[0007] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0008] A method for insulation monitoring of a dual-transformer power supply system comprises the following steps:

[0009] Startup steps: Start 1# and 2# insulation monitoring;

[0010] Steps for judging the operating status: judge the operating status of the double transformer 4P switch three-in-two power supply system;

[0011] Monitoring steps: Real-time monitoring of the power supply system.

[0012] Troubleshooting steps: If a fault is detected, first determine the fault type and then eliminate the fault.

[0013] Furthermore, two sets of insulation monitoring systems of the dual-transformer three-in-two power supply system are used in conjunction with each other.

[0014] Furthermore, the 1# insulation monitoring device maintains real-time communication with the 2# insulation monitoring device.

[0015] Furthermore, the signal acquisition access point of the 1# insulation monitoring device is from the 1# transformer outgoing line to the upper port of the 4P switch QF1, and the signal acquisition access point of the 2# insulation monitoring device is from the 2# transformer outgoing line to the upper port of the 4P switch QF5.

[0016] Furthermore, under normal conditions, the main coupling cabinet is disconnected, and the 1# insulation monitoring device and the 2# insulation monitoring device operate independently.

[0017] Furthermore, when the power supply of the transformer on either side fails, the busbar cabinet is closed.

[0018] Furthermore, under normal conditions, the busbar cabinet is disconnected, 4P switch QF1 is closed, 4P switch QF3 is open, and the 1# insulation monitoring device operates independently, executing the 1# insulation monitoring program. The monitoring range is from the 1# transformer outgoing line to the upper port of the 4P switch QF3 of the busbar cabinet.

[0019] Furthermore, under normal conditions, the busbar is disconnected, 4P switch QF5 is closed, 4P switch QF3 is open, and the 2# insulation monitoring device operates independently, executing the 3# insulation monitoring program, with the monitoring range being the circuit between the 2# transformer outgoing line and the busbar;

[0020] Furthermore, when the power supply of the 1# transformer fails, the busbar cabinet is closed, the 4P switch QF3 is closed, and the 4P switch QF5 is closed, the 1# insulation monitoring device stops running, and the 2# insulation monitoring device is operated to execute the 2# insulation monitoring program, and the monitoring range is the circuit between the 1# transformer and the 2# transformer.

[0021] Furthermore, when the power supply of the 2# transformer fails, the busbar cabinet is closed, the 4P switch QF1 is closed, and the 4P switch QF3 is closed, the 2# insulation monitoring device stops running, and the 1# insulation monitoring device is run to execute the 2# insulation monitoring program, and the monitoring range is the circuit between the 1# transformer and the 2# transformer.

[0022] Compared with the prior art, the beneficial effects of the present invention are: an insulation monitoring method for a dual-transformer power supply system, two sets of insulation monitoring systems are used in conjunction, under normal circumstances, the busbar cabinet is disconnected, and the 1# insulation monitoring and 2# insulation monitoring operate independently; when the busbar cabinet is closed, the 2# insulation monitoring device stops running and the 1# insulation monitoring device operates, and the monitoring range is the circuit between the 1# transformer and the 2# transformer, which solves the problem that the current dual-transformer three-in-two-circuit insulation monitoring system cannot be monitored and interfered with in real time. The 1# and 2# insulation monitoring devices of the present invention communicate in real time, monitor and eliminate faults in real time, and improve the efficiency of fault investigation. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a topological diagram of an insulation monitoring method for a dual-transformer power supply system according to the present invention;

[0024] Figure 2 This is a schematic diagram of an insulation monitoring method for a dual-transformer power supply system of the present invention.

[0025] Figure 3 The present invention is a schematic diagram of a busbar disconnection in a method for insulation monitoring of a dual-transformer power supply system.

[0026] Figure 4 It is a schematic diagram of a busbar cabinet closing method for an insulation monitoring method of a dual-transformer power supply system according to the present invention. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0028] The present invention provides a technical solution: a method for insulation monitoring a dual-transformer power supply system. Two insulation monitoring systems, 1# and 2#, are used in conjunction. The busbar cabinet is located between the 1# and 2# outgoing line cabinets. The 1# and 2# insulation monitoring devices communicate in real time. The signal acquisition line access point for the 1# insulation monitoring device is from the 1# transformer outgoing line to the upper port of the 4P switch QF1. The signal acquisition line access point for the 2# insulation monitoring device is from the 2# transformer outgoing line to the upper port of the 4P switch QF5. The workflow is as follows:

[0029] Start 1# and 2# insulation monitoring;

[0030] Determine the operating status of the dual-transformer 4P switch three-in-two power supply system;

[0031] The two insulation monitoring systems 1# and 2# of the dual-transformer 4P switch three-in-two power supply system work together, with real-time communication and monitoring. Under normal circumstances, when the busbar coupler is open, the two monitoring systems operate independently. When 4P switch QF1 is closed, 4P switch QF3 is open, and 4P switch QF5 is closed, the 1# insulation monitoring device (1# insulation monitoring program) and the 2# insulation monitoring device (3# insulation monitoring program) operate independently at the same time. The 1# insulation monitoring range is the circuit between the 1# transformer and the busbar coupler, and the 2# insulation monitoring range is the circuit between the 2# transformer and the busbar coupler.

[0032] If a fault is detected, the following scenarios apply:

[0033] When QF1 is closed, QF3 is open, and QF5 is closed, the 1# insulation monitoring device (1# insulation monitoring program) and the 2# insulation monitoring device (3# insulation monitoring program) are simultaneously running. (Application scenario: The monitoring range is from the 1# transformer output to the QF5 output. The application environment is when the QF2 output is powered by the 1# transformer and the QF4 output is powered by the 2# transformer.)

[0034] When QF1 is closed, QF3 is open, and QF5 is open, the 1# insulation monitoring device (1# insulation monitoring program) is running at the same time, and the 2# insulation monitoring stops; (Application scenario: The monitoring range is limited to the QF2 outgoing line with power output. The application environment is when the QF2 outgoing line is powered by the 1# transformer, and other outgoing lines are not needed)

[0035] When QF1 is closed, QF3 is closed, and QF5 is open, the 1# insulation monitoring device (2# insulation monitoring program) is running, and the 2# insulation monitoring is stopped. (Application scenario: The monitoring range is from the 1# transformer outgoing line to the QF5 outgoing line. The application environment is when the entire system is powered by the 1# transformer, such as when the 2# transformer is under maintenance.)

[0036] When QF1 is open, QF3 is closed, and QF5 is closed, the 1# insulation monitoring device is stopped and the 2# insulation monitoring device (2# insulation monitoring program) is started. (Application scenario: The monitoring range is from the 2# transformer output to the QF2 output. The application environment is when the entire system is powered by the 1# transformer, such as when the 1# transformer is under maintenance.)

[0037] When QF1 is open, QF3 is open, and QF5 is closed, the 1# insulation monitoring device is stopped and the 2# insulation monitoring device (3# insulation monitoring program) is activated. (Application scenario: The monitoring range is limited to when only the QF4 output is powered. The application environment is when the QF4 output is powered by the 2# transformer, and other outputs are not required.)

[0038] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A method for insulation monitoring of a dual-transformer power supply system, characterized in that: The dual transformer three-in-two power supply system uses two sets of insulation monitoring systems together, including the following steps: S1: Startup steps: Start 1# and 2# insulation monitoring. The signal acquisition access point of 1# insulation monitoring device is from the 1# transformer outlet to the upper port of 4P switch QF1. The signal acquisition access point of 2# insulation monitoring device is from the 2# transformer outlet to the upper port of 4P switch QF5. The 1# insulation monitoring device and the 2# insulation monitoring device maintain real-time communication. S2: Determine the operating status: Determine the operating status of the dual-transformer 4P switch three-in-two power supply system. Under normal conditions, the busbar is disconnected, the 1# insulation monitoring device and the 2# insulation monitoring device operate independently, the 4P switch QF1 is closed, the 4P switch QF3 is open, the 1# insulation monitoring device operates independently, and the 1# insulation monitoring program is executed. The monitoring range is from the 1# transformer outgoing line to the upper port of the 4P switch QF3 of the busbar; the 4P switch QF5 is closed, the 4P switch QF3 is open, the 2# insulation monitoring device operates independently, and the 3# insulation monitoring program is executed. The monitoring range is the circuit between the 2# transformer outgoing line and the busbar. S3: Monitoring steps: Real-time monitoring of the power supply system. When a transformer power supply fault occurs on either side, the bus coupler is closed. When the 1# transformer power supply fault occurs, the bus coupler is closed, and when the 4P switch QF3 and 4P switch QF5 are closed, the 1# insulation monitoring device stops running, and the 2# insulation monitoring device starts running, executing the 2# insulation monitoring program. The monitoring scope is the circuit between the 1# transformer and the 2# transformer. When the 2# transformer power supply fault occurs, the bus coupler is closed, and when the 4P switch QF1 and 4P switch QF3 are closed, the 2# insulation monitoring device stops running, and the 1# insulation monitoring device starts running, executing the 2# insulation monitoring program. The monitoring scope is the circuit between the 1# transformer and the 2# transformer. S4: Fault handling steps: If a fault is detected, first determine the fault type and then troubleshoot. When QF1 is closed, QF3 is open, and QF5 is open, the 1# insulation monitoring device is running and the 1# insulation monitoring program is executed. The 2# insulation monitoring is stopped. Application scenario: The monitoring range is limited to only the QF2 outgoing line with power output. The application environment is when the QF2 outgoing line is powered by the 1# transformer and other outgoing lines are not needed. When QF1 is open, QF3 is open, and QF5 is closed, the 1# insulation monitoring device is stopped, the 2# insulation monitoring is started, and the 3# insulation monitoring program is executed. Application scenario: The monitoring range is limited to the QF4 outgoing line with power output. The application environment is when the QF4 outgoing line is powered by the 2# transformer and other outgoing lines are not needed.

2. The insulation monitoring method for a dual-transformer power supply system according to claim 1, characterized in that: QF1, QF3, and QF5 all use 4P switches, which improves the system insulation performance and ensures system safety and stability.

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