It is Outdoor, Oil-immersed type ,used for metering and relay protection, with protective class, hair-pin type, applying to highland area, wet/dry tropical zone, which is used for metering and relay protection of 220kv, 50HZ or 60HZ system.
IEC Standard: IEC 60044-1<Current Transformer>
GB311.1<Insulation co-ordination for high voltage transmission and distribution equipment>
3. Service Condition
LB7-220(W1,W2,W3) less than 1000m
LB7-220GY(W1,W2,W3) less than 3500m
Environment Pollution Level: ii, iii, iv
4. System Condition
System Rated Voltage:220kv
System Highest Voltage:252kv
System Rated Frequency: 50HZ or 60HZ
System Neutral Earthing Method: Effectively Earthed
5. Structure Feature
- It is oil/paper insulation system, the primary insulation is wound from high voltage cable paper, and is placed several capacitor screen of voltage division in the primary insulation, which can improve electric field distributing and decrease the consumption of insulation material. It will be immersed with transformer oil after desiccating under vacuum. It has advantages of stable and reliable performance of insulation, rich successful experience, a long life time and convenient maintenance.
- Perfect fluidity performance of transformer oil is good for heat dissipation, it also has self recover ability for the failure of partial discharge caused by air bubble and dust.
- The current ratio can be changed easily by change the connection method of connecting plate on oil conservator to series or parallel connection
- Hermetically sealed stainless steel metallic bellows is installed on the top, which protect the transformer oil from moisture and extend the life time, also there is a oil level gauge on the bellows for observing the changing of oil volume.
- There is a multi function oil drain valve on the base, which make it more convenient for sampling, draining and refilling
- The primary terminal and secondary terminal board are made of epoxy casting, the seal performance is more reliable
- There is a individual terminal of earth screen on the tank
- The oil conservator and base etc use DACRAL(Zinc/Chromate coatings) for resistance to corrosion, which gives a high degree of corrosion resistance
- The primary over-voltage protection device and secondary open circuit over-voltage protection device can be provided according to the requirements of user.