Causes and search methods of common faults of the

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Causes and search methods of common faults of 10kV overhead lines

(1) short circuit fault: first, transient short circuit fault of the line (generally, the reclosing of the circuit breaker is successful); The second is the permanent short-circuit fault of the line (generally, the reclosing of the circuit breaker is not successful)

common faults are: the line metal can simplify the preparative short-circuit fault of the prototype part; Line lead jumper broken arc short circuit fault; Arc short circuit fault of drop fuse and disconnector; Short circuit fault of small animals; Lightning flashover, short circuit fault, etc

(2) ground fault: Line instantaneous ground fault; Permanent ground fault of the line

2 causes of fault formation

(1) metallic short-circuit fault of the line:

① fault caused by external force damage, overhead line or pole equipment (transformer, switch) is short circuited by external parabolic short circuit or external force scratch short circuit; The car hit the pole, causing the pole to fall and the wire to be broken; Typhoon and flood cause pole fall and line break

② fault caused by line defect, excessive sag, line collision caused by typhoon or line collision caused by electric power generated during short circuit

(2) line lead jumper broken arc short circuit fault: the line is broken due to insufficient aging strength; The poor contact of the line overload connector causes the jumper clamp to burn and break

(3) there are arc short circuit faults of drop fuse and disconnector:

① the fuse of drop fuse blows, causing fuse tube explosion or arcing, causing interphase arc short circuit

② the line aging or overload causes damage to the disconnector clamp, burning out and arcing, resulting in phase to phase short circuit

(4) short circuit faults of small animals include:

① on the pier type distribution transformer, the high-voltage down lead from the drop fuse to the transformer adopts bare wires, the high-voltage terminal of the transformer and the high-voltage lightning arrester complete the functions of pulling, pressing, bending, shearing, peeling, tearing, friction coefficient, transformation, etc. the center is an important platform to promote the development of military civilian deep integration in Guangdong Province, and is equipped with an insulating protective cover

② on the busbar of the high-voltage distribution cabinet, the busbar is not insulated, and the rat prevention in the high-voltage distribution room is not strict

③ in the high-voltage cable branch box, the bus is not insulated, and the cable branch box has loopholes

(5) lightning overvoltage

(6) the transient grounding faults of the line are:

① single-phase grounding caused by man-made external parabolic or trees touching the conductor

② the line insulator is dirty. In cloudy and rainy days or foggy weather with high humidity, there is ground flashover, which generally disappears after the weather improves or heavy rain

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(7) permanent grounding faults of lines include:

① external force damage

② line disconnectors and drop out fuses are caused by insulation aging and breakdown

③ caused by explosion of line arrester, which mostly occurs in thunderstorm season

④ direct lightning strike leads to line insulator cracking, which mostly occurs in thunderstorm season

⑤ it is caused by aging or defect breakdown of line insulator, which mostly occurs in coastal areas with serious pollution

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