A method and device for eliminating hidden defects of line protection reclosing

Abstract

The invention discloses a method and device for eliminating line protection reclosure hidden faults. A line comprises a primary electric power system line and a secondary electric power system line, and the primary electric power system line and the secondary electric power system line operate in a grid-connected mode. The method comprises the steps of detecting whether an instant single-phase earth fault occurs to the primary electric power system line or not, sending a direct tripping command to the secondary electric power system line if the fault occurs, controlling a switch protection device in the secondary electric power system line to be directly tripped after the secondary electric power system line receives the direct tripping command, and closing the switch protection device in the secondary electric power system line after the primary electric power system line and a single-ended substation return to normal. The method and device can solve the problem of the line protection reclosure hidden faults, avoids the voltage loss of the single-ended substation, and avoids the large-area power outage accidents of a power grid.

Description

technical field [0001] The invention relates to the technical field of relay protection, in particular to a method and device for eliminating hidden defects of line protection reclosing switches. Background technique [0002] With the rapid development of urban power grids, new technologies and new energy technologies are maturely applied, and more and more renewable energy and micro-grids are connected to the grid. These renewable energy sources and microgrids are usually connected to terminal substations ( figure 1 The 10kV bus in the middle dotted frame) realizes grid connection, figure 1 shown. [0003] Under the above grid structure, if a transient fault occurs on the power transmission line L on the 110kV side of the main power system ( figure 1 middle point d position), due to the access terminal substation ( figure 1 Due to the role of new energy and micro-grid in the middle dotted frame), the line L side of the main system cannot meet the reclosing condition whe...

AI Technical Summary

Problems solved by technology

When an instantaneous single-phase ground fault occurs on the 110kV line L, the DL1 sensitive section protection action trips the switch, the main power system is disconnected from the new energy and micro-grid, and the terminal substation is converted from a neutral point ungrounded system to a neutral point grounded system System, the grounding point is the fault point on the 110kV line L, which will cause the neutral point voltage to shift or increase, which will increase the voltage of the A-phase line of the 110kV line L, and further make the DL1 of the 110kV main power system line L The secondary voltage of phase A PT1 of the line L, which depends on the no-voltage reclosing condition of the side detection, also rises. If this voltage is higher than the no-voltage detection setting value of the DL1 switch reclosing, the no-voltage reclosing detection of the DL1 switch will fail. , leading to voltage loss in terminal substations, and may even lead to large-scale power outages in the power grid

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