On March 16, Pakistan local time, the engineering and technical commissioning personnel of China Electric Power Research Institute were in mertiari Lahore ± The short circuit test was carried out in Lahore station of 660kV DC transmission project.
There are two kinds of short circuit to ground on transmission line. One is short circuit. For example, if the transmission line breaks and falls to the ground, it must be repaired by sending someone to restore the power supply. The other is temporary short-circuit fault, such as the short-circuit caused by a branch hanging on the transmission line, which needs to rely on the control and protection system.
In this experiment, the UAV was used to bring copper wire close to the live line to simulate the real scene. At the moment when the copper wire approached the line, the huge arc began to burn, causing a temporary short circuit. The control and protection system immediately shifted the phase (increased the trigger angle of the rectifier station) after 10 milliseconds of the short circuit phenomenon, forcing the DC current to quickly drop to zero, After another 150 milliseconds of waiting (de dissociation), during this time, the control and protection system is looking for the location of the DC fault, determining that it is a temporary short circuit, and "directing" the DC to continue to operate! This time has lasted for 300 milliseconds, for the power supply is almost "not off"!
The test is carried out on the pole 1 and pole 2 DC lines of the station to test the DC line protection sequence and the measurement accuracy of DC fault locator.