Things to note when installing and replacing zinc oxide arresters on site
1. Technical requirements for main transformer winding neutral point arrester
1. For 220KV transformer: Y5W?-108/281 type zinc oxide arrester should be used as the neutral point of the 220KV winding, and the parallel gap should be 300mm; Y1.5W?-60/144 type zinc oxide arrester should be used as the neutral point of the 110KV winding, and the parallel gap should be 140mm.
2. For a 110KV transformer: if the neutral point insulation level is 60KV (LI325 AC140), Y1.5W?-60/144 type zinc oxide arrester should be connected in parallel with a horizontal gap of 140mm; if the neutral point insulation level is 44KV (LI250 For AC95), Y1.5W?-60/144 type zinc oxide arrester is selected in parallel with a horizontal gap of 120mm distance; for neutral point insulation level of 35KV (LI185 AC85), a separate horizontal gap of 115mm distance can be used for protection. The rod gap should be made of φ16mm galvanized round steel. The end shape is close to a semicircle without edges and corners. There is a thread at the tail end for adjustment. The gap should be arranged horizontally to prevent short circuit due to rain.
2. Technical requirements for main transformer outlet arrester
1. The outlet arresters with voltage levels of 35KV and above should be products with the same rated voltage as the busbar arresters (in principle, the same model).
2. For the 10KV bus bridge arrester of the 220KV transformer, 3 arresters should be installed and 3 discharge counters should be added. For the 10KV bus bridge arrester of the 110KV transformer, one arrester should be installed on phase B and a discharge counter should be added.
3. Specific requirements for arresters in 10-35KV switch cabinets
1. Remove all RC-type resistor-capacitor (lightning arrester) absorption devices in the capacitor cabinet.
2. Except for the busbar PT interval arrester, other arresters in the switch cabinet should be removed immediately. The lightning arrester in the capacitor switch cabinet should be placed outdoors, and the installation location is generally between the outdoor cable outlet and the capacitor; after the arrester in the outlet switch cabinet is removed, for cable outlets, the installation location is generally selected at the cable outlet end of the tower. For overhead outlets, the installation location is generally selected at the lower end of the wall casing outside the distribution room wall. Before carrying out this modification, the responsible unit must prepare the corresponding materials and maintenance tools in advance.
3. It is prohibited to use series gap zinc oxide arresters for the protection of capacitor banks.
4. It is prohibited to use the four-arrester wiring method (three connected to the star and one connected to the neutral point).
4. Technical requirements for online detectors
1. In principle, zinc oxide arresters that will be replaced in the future will use the online detector equipped by the original factory.
2. For the price of zinc oxide arresters that are not equipped with online detectors, the principles for using separately purchased online detectors are as follows: 110KV and above: JCQ-3B or JSH-3B 110KV neutral point, 35KV and below: JCQ-3C or JSH-3B
3. After online detection of damage in the same group, use the power outage opportunity to replace monitors of the same manufacturer and model. Try to ensure that the same model in the same group and the same model at the same station are consistent. If not, all three phases must be replaced and the intact ones will be used as spare parts to facilitate standardized management.
5. Technical requirements for grounding by arrester manufacturers
All arrester base foundations must adopt a double grounding method, that is, two grounding down conductors are welded to two points on different sides of the grounding grid voltage equalizing belt.
Yichang Hengyuan Technology Co., Ltd. specializes in the production of European-style cable joints, plug-and-pull heads, cable branch boxes, American-style elbow joints, high-voltage vacuum circuit breakers, high-voltage load switches, arresters, zinc oxide arresters, tank arresters, over-voltage protectors, counters, monitors, heat-shrinkable cable accessories, Manufacturer of cold shrink cable accessories, T-heads, wall bushings, European cable accessories, American cable joints, transformer neutral point protection devices, fuses, isolating switches, PT cable heads, elbow cable joints, 10kV outdoor terminals, switch cabinets, cable intermediate joints, cable accessories and other products
