Four quick-check methods for fault points of leakage protectors

In daily electricity management, many rural electricians find it difficult to find fault points of leakage protectors and take up a lot of working time. In practice, the author has explored 4 quick-check methods for leakage protectors for reference by agricultural and electricians. 1 Intuitive inspection method Intuitive inspection method is that inspectors analyze and judge the fault phenomenon, and the protection area includes leakage protector and is protected. In the daily electricity management, many agricultural electricians feel that the leakage protector fault point is difficult to find, and it takes up a lot of Working hours. In practice, the author has explored 4 quick-check methods for leakage protectors for reference by agricultural and electricians. 1 Intuitive inspection method Intuitive inspection method is that the inspectors analyze and judge the fault phenomenon, and conduct an intuitive inspection of the protection area, including the leakage protector and the protected line equipment, so as to find the fault point. During patrols, the inspection should focus on the corners, branches, crossovers and other complex sections of the line and points prone to faults. This method is simple and easy to implement, and is suitable for finding obvious fault points, such as wire breakage to the ground, pull wire and wire contact, and wrong wiring. 2 Trial delivery method This method mainly finds the fault of the leakage protector itself, rather than the external fault. The specific operation method is: first cut off the power supply, then remove all the load-side leads of the zero-sequence transformer of the leakage protector (remove the outgoing line directly from the secondary and tertiary leakage protectors), and then turn on the power supply. If the protector is still If it cannot be put into operation, the leakage protector itself is faulty and should be replaced or repaired. If it can operate normally, the protector has no fault, and then find out whether the fault occurs in the switchboard or outside. The specific operation method is: first cut off the power supply of each outlet or the load side of the AC contactor. If it fails to operate, it means that there is a fault on the distribution board. Check whether the electrical, instrument and other equipment are well insulated and whether the wiring is correct. If it can operate normally, there is no fault on the switchboard. After confirming that the fault occurred on the outside line, the fault point can be found by the method of dividing line elimination. 3 Distributed line elimination method When it is confirmed that the fault occurs on the external line, you can disconnect each branch line of the low-voltage power grid according to the sequence of 'main trunk first, then branch, rear endIf the trunk line is fault-free, then the trunk line can operate normally. Then, put the branches and ends into operation. When a line is put into operation, the protector acts, and the fault point is on which line, you can focus on finding the fault point on this line. 4 Numerical comparison method Numerical comparison method is to measure the line or equipment with the help of an instrument, and compare the measured value with the original value, so as to find the fault point. It needs to be pointed out that when the insulation of the neutral line of the line drops or the neutral line of the equipment is repeatedly grounded, it is easy to cause the main protection to trip frequently, and the secondary protector does not trip. When solving the tripping of the secondary protector, the method of swapping the phase line and the neutral line should not be used to put the secondary protector into operation, and the repeated grounding wire of the equipment should be removed in time.