Method for Improving Power Quality of Power Grid in Isolated Grid Operation Before and After Start-up and Stop of High-power Equipment

Abstract

The invention discloses a method for improving the electric energy quality of a power grid in isolated net operation before and after starting and stopping of high-power equipment. An energy storage system is added into a power grid in isolated net operation and consists of a grid-connected switch, an energy storage feeding transformer, a bidirectional inverter and an energy storage device. The energy storage device is connected to a high-voltage bus of a self-generation power plant by the bidirectional inverter, the energy storage feeding transformer, and the grid-connected switch; and the high-voltage bus of the self-generation power plant is used for completing electric energy collection and distribution. The method has following beneficial effects: on the basis of the absorption process of the electric energy by the energy storage system, problems of grid frequency rising and voltage rising after working stopping of the high-power equipment of the power grid can be solved; and energy wasting caused by an excessive grid power phenomenon can be avoided. On the basis of the releasing process of the electric energy by the energy storage system, problems of grid frequency reduction and large voltage drop due to starting of the high-power equipment of the power grid can be solved; and grid backout caused by an insufficient grid power can be avoided.

Description

technical field [0001] The present invention relates to a method for improving the power quality of the isolated grid operation power grid before and after the start and stop of high-power equipment, in particular to a method for the power quality of the isolated grid operation grid before and after the start and stop of high-power equipment in industrial and mining enterprises with thermal power generating units as self-provided power plants method. Background technique [0002] For a long time, due to the customary way of thinking and the lack of safety guarantee technology for isolated grid operation, most of the self-provided power plants in the country must be connected to the grid to operate. In the case of grid-connected power generation, the burden on enterprises is also heavy due to the high cost. For the power generation industry in the whole country and even the world, some power generation enterprises implement isolated grid operation, but it is very unstable an...

AI Technical Summary

Problems solved by technology

For the power generation industry in the whole country and even the world, some power generation enterprises implement isolated grid operation, but it is very unstable and the power quality is poor

The reason is mainly that the power plant operating in an isolated grid cannot solve the impact of the generator cycle fluctuation caused by the large load shock and the frequent fluctuation of the small load, the unit is often overrun, or cannot run at all

Self-provided power plants are mostly used in high-energy-consuming enterprises, and isolated grid operation is even more difficult

Because there are many high-power equipment in high-energy-consuming enterprises and most of them are the most unstable loads, the start and stop of large motors, the lifting and lowering of electric arc furnace electrodes, and mechanical and electrical failures will directly affect the stable operation of self-provided power plant generator sets

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