how does a high voltage switchgear work?eg, how to turn it on and off...?

Answer 1

The term "switchgear" can be used to describe different electrical devices and does not have an exact meaning. High voltage also has the same problem because it is used to describe most any voltage over 240V which is used to supply most residential housing services. Switchgear could be used to describe equipment used to distribute electricity to multiple circuits from one point to many different areas in large buildings, factories, plants, etc. and is most always part of a three phase feeder service from the power company. Example.....A large grocery store might have a 2500Amp, 277V/480V, three phase service. The main breaker for that service will be rated for 2500Amps. This breaker will feed many other subpanels that will be used to supply current to 3-phase motors in the air handling units that keep the store cool in the summer and warm in the winter. There will be breaker circuits for the refridgerators and freezers for food preservation. There will be ciruits for all the light fixtures and ciruits for the cash registers and office space. So the 2500A main breaker would "feed" the panel for the air handling units and that panel could have a 1000Amp breaker for its overload protection. The main might feed a 400Amp panel that is used for the light fixtures and another 400Amp panel for the refridgerators and freezers. There may be a couple of 200Amp panels for the other equipment I previously mentioned. Of course all these panels cannot excide the 2500Amp main breaker or it would "trip" and shut the power off to the whole store. All the electrical equipment is bolted together and mostly housed in the same area or room. These multiple panels that are feed from the main 2500Amp breaker and the conductors and enclosures that contain them are commonly called "switchgear". To answer the last part of your question there are switches that you flip, push, pull, or "throw" ( a long handled switch ). that cut the power on or off to the circuits that the subpanels feed.

Answer 2

Not sure what you mean by "high" voltage. If you're talking about voltages over 12,000 volts most of that stuff has to be unloaded before the circuit can be switched.

Some transformers have switches that are immersed in an insulating oil, the switches are spring operated and to switch them on and off you have to ratchet the spring into position and and operate a trip mechanism which actually opens or closes the switch.

The cut-out switches sometimes see on over head power lines won't disconnect under load. When you open the switch the voltage is so high it creates an arc and the arc can travel across the open switch.

Bottom line is if you have to ask, don't mess with it. Utility workers experienced in messing with this stuff get killed and maimed all the time. You wouldn't stand a chance, because you don't have to touch the wrong thing to get fried just get too close. High voltage will reach out and get you.

Answer 3

well, for verry high voltages like 500k(500,000 volts) you need to get as much distance between the lines as pocible. they basicly take a large metal ball and cup(that fits around the ball) and connect them to long rods. the ball is fitted into the cup and held by the rod realy far apart(each rod is like 10 feet long) and both are connected to the power lines. when the power is on, the ball and cup are held to gether. when it is turned on, they are pulled apart and a large electrical ark is produced. it starts close and raises up about 50 feet.