Method for protecting low-voltage bus of intelligent substation

Abstract

The invention discloses a method for protecting a low-voltage bus of an intelligent substation. The method is achieved through a bus protection device and branch protection measuring and control devices connected with the bus protection device in a cooperation mode, the bus protection device is started through steady current overflowing elements and current variable quantity elements of the active branch protection measuring and control devices, action allowing signals are sent to the bus protection device through power direction elements or the current overflowing elements of branches, and bus composite voltage blocking elements are adopted as the open condition of a bus fault. Internal and external faults of a bus region are judged by the bus protection device in the mode of combining starting signals and the action allowing signals, when the three conditions are met at the same time, the bus fault is judged, the bus protection device acts to remove the faulted bus, and a fault of a segmentation dead region and a fault of a transformer low-voltage side dead region can be judged and isolated. The bus faults with voltage classes of 35 kV and below can be removed fast and accurately, and the method can be directly applied to a digital substation or the intelligent substation.

Description

technical field [0001] The invention relates to the technical field of electric power system relay protection, in particular to a low-voltage (35kV and below voltage level) busbar protection method of an intelligent substation. Background technique [0002] At present, the 35kV and below voltage level systems in high-voltage substations have many outlets and frequent operations, and bus faults often occur due to small animal hazards, equipment insulation aging, and mechanical wear and tear. However, the current busbars with a voltage level of 35kV and below are not equipped with special busbar protection. The fault is removed by the time-limited quick-break protection installed on the low-voltage side of the transformer. It takes a long time to remove the fault, which increases the damage of the equipment and easily causes adjacent A large area of ​​equipment will be burned, and even the main transformer will be burned in severe cases. If the conventional busbar configurati...

AI Technical Summary

Problems solved by technology

Although the above technical solution reduces the usage of secondary cables, in the implementation process, each protection measurement and control device must receive the GOOSE signal of other protection measurement and control devices and judge whether there is blocking information to decide whether to skip the interval, which increases the number of devices The complexity of configuration and network transmission; at the same time, as mentioned in the plan, "using the outgoing line protection measurement and control device, the section circuit breaker protection measurement and control device, and the incoming line protection measurement and control device (including the interface unit on the low-voltage side of the transformer) to complete the determination of the fault point, The method of using section circuit breaker protection measurement and control devices and incoming line protection measurement and control devices (including the interface unit on the low-voltage side of the transformer) to complete bus fault removal does not consider the situation that the bus has power outlet branches

In this case, it is not possible to isolate the fault by switching only the section and incoming circuit breakers

In addition, the above method does not consider the faults at the low-voltage side of the transformer and the location of the dead zone of the section, and the isolation of dead zone faults cannot be achieved

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