10kV overhead cable is characterized by more rural power lines, power supply radius length, all radial supply line. After recent years of rural power grids, typhoons and lightning empowerment, but 10kV overhead line incidents still occur, this paper analyzes accidents often occur on 10kV overhead lines, and anti-accident measures were discussed 10kV overhead cable in order to improve the safe operation of 10kV overhead cable.
Common causes of accidents and analysis of 10kV overhead cable
Depending on the operating experience, common accidents with 10kV overhead cables are the following:
1. Lightning Accident
10kV overhead cable lightning accident there are many, there are insulators breakdown or burst, break, distribution transformer burned. Lightning accidents, although there is lightning line with this objective reasons more related to equipment defects and also have a great relationship, analyze the device main reasons:
(1) The insulator quality, but off. Especially the P-15, P-20 pin insulators quality defects, nearly two years, the frequent occurrence of lightning strikes in the region pin insulator burst accident, causing 10kV line to ground or phase short circuit.
(2) Inadequate 10kV Line Lightning Protection. Starting at the end of 1998, many areas of distribution transformers are replaced with the MOA, but some long 10kV overhead cable, but no line-type zinc oxide arrester.
(3) wire connectors bad. Many areas were previously accustomed to using and groove clamp connector 10kV lines as even and do not have and winding groove clamp connection, and groove clamp connections or wiring is not the best connected winding wire, wire connection is bad, will unable to withstand the impact of a strong lightning current.
(4) Lightning grounding device failed. Substandard grounding, grounding resistance of greater than 10 ohms, low discharge current capacity, the lightning current into the earth can not fast.
2. Typhoon blows down the tower
According to the maximum design wind speed 25 m / sec designed tower, scraping 10 typhoons or less, the tower is no problem, major typhoon toppled tower reasons:
(1) 10kV lines and towers are not according to design requirements and construction, tower foundation is not solid or buried deep enough.
(2) typhoon wind speed exceeds the maximum design wind speed. 10 typhoon wind speed of 25 m / sec, 11 typhoon wind speed of 30 m / sec, 12 typhoon wind speed of 33 m / sec.
3. The external damage accident
External damage is one of multiple incidents 10kV overhead cable, such incidents, according to the damage can be divided into:
(1) vehicle collision caused by contact 10kV overhead line down the pole (tower).
(2) Kite touch phase short circuit caused 10kV overhead cable speed off the trip.
(3) tower wood tower, causing the tower tilt fittings stolen or down rod (column).
(4) or cable tower base foundation was emptied and destroyed, causing lever down (column).
(5) The illegal construction of tools or materials phase short circuit caused by touching the wire speed off the trip.
The circuit is overloaded or wire connector poor contact caused by heat, broken accident.
5. Line equipment is worn out and defective
The above analysis is that some common accident 10kV overhead cable, these incidents on the line of great harm, cause greater damage to the local industrial and agricultural production, the inconvenience to the local residents. Here's how to reduce accidents 10kV line and guarantee the safe operation of the line to talk about anti-accident measures.