The role of the lightning arrester is to protect various electrical equipment in the power system from lightning overvoltage, operating overvoltage, power frequency transient overvoltage and other damage caused by an electrical appliance. The types of arresters are mainly protective clearance, valve-type arresters and zinc oxide arresters.
13831205665 13833216028 24-hour hotline 13831205665 13833216028
|lightning arrester||lightning arrester|
The role of the lightning arrester is to protect various electrical equipment in the power system from lightning overvoltage, operating overvoltage, power frequency transient overvoltage and other damage caused by an electrical appliance. The types of arresters are mainly protective clearance, valve-type arresters and zinc oxide arresters. The protection gap is mainly used to limit atmospheric overvoltages, and is generally used for the protection of incoming line sections of power distribution systems, lines and substations. Valve-type arresters and zinc oxide arresters are used for the protection of substations and power plants. In 500KV and below systems, they are mainly used to limit atmospheric overvoltage. Backup protection.
Lightning arrester use conditions:
Ambient temperature: not lower than -40 ° C, not higher than + 60 ° C.
The altitude does not exceed 3000m, and beyond 3000m can be based on actual conditions.
Power grid frequency: 48 ~ 52Hz (50Hz system), 58 ~ 62Hz (60Hz system).
The voltage applied to the arrester for a long time must not exceed its rated voltage.
The air at the installation site should not contain chemically corrosive gases, steam, or explosive dust. If required, it must be specified when ordering.
Lightning arrester-operation and maintenance
In daily operation, check the contamination of the surface of the porcelain sleeve of the arrester, because when the surface of the porcelain sleeve is seriously polluted, the voltage distribution will be very uneven. In a lightning arrester with a shunt resistor, when the voltage distribution of one of the components increases, the current through its shunt resistor will increase significantly, and the shunt resistor may be burned out and cause a failure. In addition, it may affect the arc extinguishing performance of valve type arresters. Therefore, when the surface of the porcelain sleeve of the arrester is seriously dirty, clean it in time.
Check the lead and grounding lead of the arrester for signs of burns and strand breaks and whether the discharge recorder has been burned. It is easy to find the invisible defect of the arrester; check whether the seal at the upper lead of the arrester is good, and the arrester will seal if it is not well Water is prone to accidents due to moisture. Therefore, the joint between the ceramic sleeve and the flange should be checked for tightness. A waterproof cover can be installed on the lead of the 10 kV valve type arrester to prevent rainwater from seeping in. Whether the electrical distance between them meets the requirements. The arrester should be as close as possible to the protected electrical equipment. The arrester should check the operation of the recorder after a thunderstorm; check the leakage current and the power frequency discharge voltage is greater than or less than the standard value. Test; when the discharge recorder is operated too many times, it should be repaired; cracks in the joint between the porcelain sleeve and the cement; when the flange and rubber pads fall off, they should be repaired.
The insulation resistance of the arrester should be checked regularly. When measuring, a 2500 volt insulation shaking table is used. The value obtained from the side is compared with the previous result. If there is no obvious change, it can continue to be put into operation. When the insulation resistance decreases significantly, it is generally caused by poor sealing and moisture or spark gap short circuit. When the insulation resistance is lower than the qualified value, a characteristic test should be performed. When the insulation resistance significantly increases, it is generally due to poor contact or break of the internal parallel resistance As well as spring slack and separation of internal components.
In order to detect the hidden defects inside the valve type arrester in time, a preventive test should be carried out before the annual thunderstorm season.