In addition, it is also responsible for reducing the failure rate of distribution line switches, reducing the failure of GW9 outdoor high-voltage disconnector (circuit breaker) and building MSTP multi-service transmission platform.
Distribution operation inspection is the operation, maintenance and overhaul of distribution lines, and is responsible for the operation, maintenance and overhaul of distribution lines (10KV lines, low-voltage lines, etc.). ) and power distribution equipment (transformers, low-voltage fuses, load switches, meters, etc. ).
Power distribution is a link in the power system that directly connects with users and distributes electric energy to users. The distribution system consists of distribution substations, high-voltage distribution lines, distribution transformers, low-voltage distribution lines and corresponding control and protection equipment. Therefore, regular inspection is particularly important.
Extended data:
Commonly used AC power supply methods in power distribution system are:
① Three-phase three-wire system. It is divided into triangle wiring (0.4kv motor and lighting) and star wiring (used for low-voltage three-phase 0.23kv industrial lighting distribution and 0.23kv three-phase motor).
② Three-phase four-wire system. Used for 0.4kv/0.23kv low-voltage power and lighting mixed distribution.
③ Three-phase, two-wire and one system. Mostly used in rural power distribution (because security problems have long been eliminated).
④ Single-phase single-wire system is 27.5kv, which is often used for traction power supply of electrified railways.
⑤ Single-phase two-wire system 0.23kv (obtained by three-phase four-wire system). Mainly to supply electricity to residents.
Commonly used DC power supply modes in power distribution system are:
① Two-wire system. Used for power supply of urban trolleybuses, subway locomotives, mine traction locomotives, etc.
② Three-wire system. Supply power plants, substations, distribution stations, secondary equipment, electrolysis, electroplating.
The primary distribution network is the network from the outlet of the distribution station to the entrance of the distribution station (or substation). It is also called high voltage distribution network in China. The voltage is usually 6~ 10 kV, and 10 kV distribution is often used in cities.
With the increase of urban load density, 20 kV distribution scheme has been adopted. The main part of the primary distribution line from the distribution station is called the trunk line. The part separated by the trunk line is called the branch line. The branch line is connected with the distribution transformer. There are two connection modes for primary distribution network: radial and ring.
The secondary distribution network is a system composed of lines and components between the secondary outlet of distribution transformer and the customer's household line, also known as low-voltage distribution network. In addition to radial and ring connection, important users in cities can also use double-loop connection.
In urban areas with high power load density, grid wiring is adopted. This kind of network is powered by several primary distribution trunk lines, and after being stepped down by distribution transformers, it is connected to the secondary distribution network through low-voltage fuses.
Because the adjacent distribution transformers in the secondary system are connected to different primary distribution trunk lines, the downtown power failure caused by primary distribution line failure can be avoided.
Distribution lines have overhead lines and underground cables according to the structure. Overhead lines can be used in rural areas and small and medium-sized cities, and underground cables should be used in big cities (especially downtown areas), tourist areas and residential areas.
References:
Work of Power Distribution Inspection Room of State Grid Xiamen Power Supply Company-Xiamen Power Grid