High-voltage isolating switch for inspection and maintenance during operation

The high-voltage isolating switch should be patrolled frequently during operation, and should be inspected and maintained before and after operation.

(1) Contact temperature. The isolating switch in the closing position shall have no overheating at the contact and connection points. The maximum allowable temperature is 70 °C. The load current shall be within the capacity range and shall not exceed the rated value. Otherwise, the large capacity switch should be replaced in time.

(2) Whether there is any defect in the contact site. Check the blade and the contact parts for burn marks, and check the porcelain insulation for damage and discharge. If there is burn marks, it should be polished in time and coated with a layer of neutral petroleum jelly.

(3) Check the condition of the parts. Check whether the screws of each component are loose and the contact pressure is appropriate. Otherwise, it should be trimmed; check whether the components of the operating mechanism are open, deformed or rusted, whether the shaft pin and the fastening nut are normal; check whether the opening and closing are closed. The phenomenon of jamming, the center of the joint should be calibrated, and the three phases should be in contact at the same time; the surface of the insulator and the operating connecting rod of the isolating switch should be kept free of dirt, foreign matter, cracks, defects or flashover.

(4) Contact of the blade with the contact. Check whether the blade is in close contact with the contact. It can be tested with a feeler gauge of 0.05mm thick and 10mm wide. The insertion depth should not exceed 5mm.

(5) The distance between the static contact of the isolating switch and the blade. For the isolating switch in the opening position, the distance between the static contact and the blade should be as far as possible. If it is too small, flashover may occur, causing the device under maintenance to be charged and causing an accident. The safety distance is shown in the table.

Safety distance reference data between the table static contact and the blade

(6) Regularly check the insulation of porcelain parts. Regular power outages should be checked and found to be poorly insulated. New parts should be replaced in time.