Research On Application Of20kV Voltage Grade In Taizhou Linhai New Hairbor City

Adopt20kV Voltage Grade can improve the stability of power system, The power quality and operation of the economy, lessen the investment etc advantages. In the reform of the distribution network,The selection of neutral point grounding modes has a significant influence on the selection of relevant equipments and the system operation. This article analyses about the advantages of20kV Voltage Grade,and simulation about the characteristics of three different neutral point grounding modes, grounding though Peterson coil,grounding through small resistance and flexible neutral grounding mode.This article,provides the technical reference about the selection of The neutral Point grounding modes, also present the project of the reform flexible neutral grounding mode.Power industry is the backbone of the national economy, in order to meet the needs of economic and social development, accelerate the construction of power engineering, adjust the structure and layout of the electricity network, a reasonable choice and timely improve the power grid voltage level, especially in medium voltage distribution voltage levels, alleviate the current power shortage, and effectively promote the healthy and orderly development of the power industry is crucial. Currently our presence in the city power grid to meet the supply situation has taken the following main issues:distribution capacity is small, smaller than the capacity-load transformer capacity; high voltage grid fragile, a large distribution network equipment obsolescence, low reliability; High in the low-voltage power line loss rate is still; voltage quality is not high; standard and low power design. MV distribution plays a role in the nexus between the high and low voltage power distribution, medium voltage level choices directly affect the stability of power systems, power quality, economy is good or bad, at this stage of China’s most used lOkV medium voltage distribution grid as a contact and communication among high and low voltage power distribution grid, although10kV medium voltage distribution network in the development process of China’s power grid indeed played an important role in promoting, but with the economic development of China’s major cities with electricity increased rapidly in Shanghai, Wuhan, Guangzhou and other cities load density has reached10MW/km2, especially the downtown area even more than the50MW/km2, some areas have medium voltage distribution network voltage level rises20kV,35kV, some experts proposed the use of a medium voltage distribution network voltage level, which will be greatly changed in the system power supply capacity, power quality, line losses, voltage drop and so on. However, as the device has not been miniaturized, cost is relatively high, the use of35kV medium voltage distribution network as voltage level, the investment costs and annual operating costs would result in a significant increase, and therefore should not be used at present.