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Lightning Protection Of The Substation
- Nov 09, 2017 -

The lightning strike of the substation is downward, mainly from two aspects: one is that lightning strikes the electrical equipment of the substation;The second is the inductive lightning overvoltage of the overhead line and the path of the lightning circuit of the lightning overvoltage.Therefore, it is very important to protect the transmission line and transformer damage by direct strike and lightning.

1. Direct lightning protection of substation.

The lightning rod is the main measure of direct lightning protection. The lightning rod is the lightning receiver that protects electrical equipment and buildings from direct lightning.It absorbs it and safely imports it, thereby protecting the nearby insulation level from lightning strikes.When installing a lightning rod, the 35kv substation must be equipped with an independent lightning rod, and can meet the requirement of no counterattack.For substation 110 kv and above, because of this kind of voltage level distribution equipment insulation level is higher, the lightning rod can be installed directly on the architecture of power distribution device, therefore, high potential produced by lightning rods will not result in electrical equipment against accidents.

2. Protection of intrusion wave by substation.

The main measures for the protection of intrusion wave by substation are the valve type arrester on its entrance.Valve type lightning arrester, the basic element for the spark gap and non-linear resistance, at present, the FS series valve type arrester as the spark gap and nonlinear resistance, mainly used to protect small capacity distribution equipment SFZ series valve type lightning arrester, mainly used to protect the medium and large capacity of substation electrical equipment;FCZ1 series magnetic blow-valve type arrester is mainly used to protect the high voltage electrical equipment of the substation.

3.Protection of the incoming line of substation.

The purpose of the lightning protection protection is to restrict the lightning current amplitude and the steepness of the lightning.When line overvoltage on, there will be a traveling wave along the wire to the substation movement, its amplitude 50% of the line insulation impulse flashover voltage, the impact of the line pressure is much better than the substation equipment of impact pressure.Therefore, it is the main measure of lightning protection to install the lightning conductor close to the substation.If there is no set up wire, when close to the substation lightning strike into line, through the thunder and lightning arrester current amplitude can be more than 5 ka, and its gradient will exceed allowable values, is bound to cause damage to line.

4.Protection of transformer.

The basic protection of the transformer is close to the transformer installation arrester, which can prevent the transmission of the wire from damage insulation.When installing the arrester, close to the transformer as far as possible, and minimize the length of the wire, so as to reduce the pressure drop of the lightning current on the connection line.At the same time, the metal shell and the connection of surge arrester shall be the transformer neutral point on the low voltage side together, such, when invading wave make arrester gesture, effect on the high side of main insulation voltage is left with a residual pressure surge arrester (not including the pressure drop of the voltage on the grounding resistance), reducing the chance of lightning damage to the transformer.

5. Lightning protection grounding of substation.

Substation lightning protection after meet the requirements, but also according to the requirements of work safety and earthing laying a unified grounding network, and then under the lightning rod and lightning arrester increase to meet the demand of the lightning protection and grounding body or separate grounding body laying under the lightning protection device.