Scheme Research Of 10kV Boost For 20kV Distribution Network

At this stage, medium voltage power grid in China is mainly on 10 kV voltage level. But compared with the 20 kV voltage grade,10 kV power grids has its limitations.20 kV the voltage level is particularly suitable for high load density, site and corridor resource city center area, also suitable for power supply of long distance, large pressure drop in remote rural areas, in the conditions suitable for the area, urban power grid with 20 kV voltage grade is the inevitable trend of development.In 10 kV voltage level of our country should be based on 110 kV substation 10 kV power system reform gradually to 20 kV power system, we need to find a method is feasible and reliable and effective.Firstly, this paper compares the power capacity, voltage loss, power supply radius, line loss, low voltage side short circuit current, non-ferrous metal consumption, reliability evaluation, voltage deviation index,20 kV power grids has greater advantage. Introduced in foreign countries, such as Japan, France, Britain, Italy, Germany and other countries,20 kV power system has been widely used, but at home, such as the Suzhou Industrial Park and Liaoning Benxi area, also began to use 20 kV power system.Secondly, transformation of primary equipment-the main transformer based, proposes the use of a dual voltage transformer for 20 kV,10 kV two voltage levels, facilitate the transition and boost; wiring group and the 20 kV main transformer, changes and medium with 20 kV voltage level transformer allow the capacity, combined with the actual operation of the current transformer, analyzes the 20 kV voltage grade medium pressure, the change of main transformer capacity, by calculating the rated capacity of main transformer is recommended to get the value of the.Then, the transformation of the neutral point grounding mode, put forward a kind of arc suppression coil with parallel resistance of the flexible ground, can satisfy the withstand voltage level of equipment requirements, but also can reduce the line fault tripping rate in transient faults, to ensure power supply safety and continuity; and analysis of the grounding faults and single phase in the normal operation of the grid, single-phase permanent fault case, flexible ground fault principle.Then, the transformation of the relay protection, proposed based on relay protection for 10 kV power grid on zero sequence over current protection; and analysis of the 20 kV line, neutral and transformer zero sequence current protection configuration and setting of the.Finally, a simple study in the step-up the transformation process, the other is a device, such as the feasibility and technology of power line, switch, circuit breaker and its insulation problems.