Method and device for quickly restoring system power supply

Abstract

The method for rapidly restoring power supply of a system disclosed in the present invention includes the following steps: dividing the reclosing delay into delay 1 and delay 2 through the reclosing function module and timing them separately; the two times are judged in parallel to realize fast reclosing , and send the reclosing command to the start standby automatic switch module; judge the system failure and operation status by starting the standby automatic switch module, and send the start standby automatic switch command to the standby automatic switch module after judging the reclosing failure; After the automatic switch module receives the command to start the standby automatic switch, it directly starts the standby automatic switch logic without delay cooperation, cooperates with the backup power supply, and quickly restores the system power supply. The invention also discloses a device for quickly restoring system power supply. The invention can realize rapid reclosing after a fault occurs in the power grid and a switch trips, thereby improving the probability of successful reclosing. When the reclosing failure is judged, the standby automatic switching is started directly, and the power supply of the system is quickly restored.

Description

technical field [0001] The invention relates to a method and a device for quickly restoring system power supply in a power system. Background technique [0002] When a fault occurs in the transmission line of the power system, the line protection device quickly trips the line switch after judging the fault, isolates the fault, and then performs reclosing judgment. If it is a transient fault, the recloser will successfully restore the system power supply; if it is a permanent fault, the switch will be tripped again and the recloser will be locked, and the backup power self-injection device (referred to as the backup self-injection device for short) will close the backup power supply to restore the system power supply . [0003] Conventional reclosing discrimination methods such as figure 1 shown. figure 1 The delay time of medium and heavy closing needs to take into account the time when the switch is released from the arc and the anti-shake time of the synchronous and no-...

AI Technical Summary

Problems solved by technology

For small hydropower or small systems with many new energy sources, isolated grids are likely to be formed after a fault trips, and the recloser faces the following problems, resulting in the success of conventional recloser detection of no-voltage or synchronous detection even if a transient fault occurs The rate is also lower:

[0004] 1) No-voltage inspection and closing: If the output of the generator in the local isolated grid is smaller than the load and the unbalance is large, the local isolated grid cannot maintain stable operation, but the isolated grid can still run for a long time, and the no-voltage inspection condition is not satisfied , it is necessary to wait for the local isolated network to be dragged down before reclosing. Since the residual voltage disappears for a long time, it may exceed the entire group time of the device, resulting in the failure of the no-voltage detection and closing.

[0005] 2) Check synchronous closing: If the difference between the generated power of the local isolated grid and the load is large after the fault, the frequency difference between the isolated grid and the main grid may reach a large value in a short period of time, and the longer the reclosing delay, The frequency difference between the isolated network and the main network will be larger, resulting in the failure of synchronous detection and closing.

This time is often longer, and may not meet the requirements for fast restoration of system power supply

Images