High Voltage Circuit Breakers

Electrical power transmission networks are protected and controlled by high-voltage breakers.

SF6 gas filled and spring mechanism operated CBs are widely used in modern EHT systems

Basic operating principle of these breakers does not vary from any other LV or MV CBs

Sulphur hexafluoride (SF6) gas is a good arc quenching medium due to its low ionization property

SF6 has good insulation properties too

The chambers and the supporting hollow insulators are filled with SF6 gas

In the previous picture, the breaker is operated using a gang operated single mechanism box

CBs with separate operating mechanism box for each pole are also in use.High Voltage Circuit Breakers

SF6 High Voltage Circuit Breakers

Power Frequency High Voltage Test on PT

This is the test that determines the healthiness of insulation A high voltage at the power frequency is applied on one of the windings with the other being shorted together and earthed along with the tank. HV test voltage varies for VTs used in Earthed and Un-earthed systems. In earthed system, one end of the primary of the PT is connected to the earth through an earth link. whereas in the unearthed system, primary is not earthed. In case of earthed system, the high voltage applied on the primary side will be only 3KV irrespective of its rated voltage. In case of Un-earthed system, the High voltage is applied on the primary side with secondary and tank are earthed together.

For eg: If the test is done on the 33KV side of a PT, 70KV is applied on the winding with the secondary shorted and connected to earth. This voltage is maintained at the terminals for one minutes, during which there shall not be any flash over or collapse of voltage.

News Trends in High Voltage Transmisison Line Towers Design

Sea this High Voltage Transmission Line Towers designed for Iceland. This tower is prefabricated and erected on concrete structure. Watch the different views. Also read the article titled at High Voltage Transmission Line Towers by Arphenotype! Shre your ideas and participate in the discussions!

Outdoor high-voltage AC SF6 breaker made in China

Outdoor high-voltage AC SF6 breaker is used to control EHT Power of the range 110 kV.LWA-126/T3150-40 type outdoor high-voltage AC SF6 breaker is porcelain type SF6 breaker, it adopts a self extinguishing interrupter structure,the

interrupter is located in a insulated porcelain housing and the SF6 gas works as the insulation and arc-extinguishing media, also the springmechanism is equipped; this kind of breaker is widely used inhydro powerstation, city network substation and large power stations,where the breaker controls and protects the power transmission line. This China make product is very cheap and worksatisfactory.

Thisoutdoor high-voltage AC SF6 breaker is fromTianshui Changcheng Switchgear Co.,Ltd (CTCS) is alarge-scale professional company in China`s manufacturing field of transmission and distribution switchgear, is a backbone enterprise ofLanzhou Great Wall Electrical Stock Limited Company.The company located in Tianshui CityIt mainly produces 0.4-126KVswitchgears, electrical components and LV switchgears. The products arewidely used in national large-scale power projects and otherlarge/middle industrial projects such as: petrol-chemical,metallurgy,transportation,mine and construction etc.

Read more at http://www.mvvacuumcircuitbreaker.com/pro.asp?id=11