Flexible island grid-connection control device and method for smart power grids

Abstract

The invention provides a flexible island grid-connection control device and method for smart power grids. The device comprises flexible inversion units, single-phase electric power detection units, GPS phase detection units, an island grid-connection detection unit, a communication unit and a master control unit. Each flexible inversion unit comprises an angle form differential voltage topological circuit and a star connection type inverter circuit. Each single-phase electric power detection unit is connected with the output end of the corresponding star connection type inverter circuit and a PCC nodal point. Each GPS phase detection unit is connected to the output end of the corresponding star connection type inverter circuit and a PCC nodal point. The input end of the island grid-connection detection unit is connected to the output ends of the single-phase electric power detection units at the PCC nodal points and the output ends of the GPS phase detection units at the PCC nodal points. The output end of the island grid-connection detection unit is connected with the input end of the master control unit. According to the flexible island grid-connection control device, the flexible inversion units composed of novel topological structures can make a micro power grid and a main power grid conduct flexible grid-connection and conduct switching of islanding modes, so that impact of the micro power grid on the circuits is reduced.

Description

technical field [0001] The invention belongs to the technical field of micro-grids, in particular to a flexible island-grid-connected control device and method for smart grids. Background technique [0002] With the development of economy and society, energy consumption is increasing, environmental pollution and the rapid growth of electricity demand make people pay more and more attention to the development of renewable energy. Therefore, the proportion of micro-grids has been increasing year by year in recent years, so the control of micro-grids has become very important. Microgrid has the characteristics of limited capacity, small damping, and poor stability, which greatly restricts the development of microgrid. [0003] Since the microgrid mainly has two operating modes, the main control methods are also divided into two types, but both have certain defects. The droop control (P-f, Q-V) is mainly used for the microgrid control in isolated island operation. However, due...

AI Technical Summary

Problems solved by technology

The droop control (P-f, Q-V) is mainly used for the microgrid control in isolated island operation. However, due to the large fluctuation of the load in the microgrid, the simple droop control will cause a large frequency deviation and voltage amplitude deviation, resulting in a large circulating current. And grid instability; for grid-connected microgrid control, P / Q control is mainly used to ensure that the microgrid outputs a fixed common and reactive power, but when the microgrid and the main grid are disconnected, the microgrid will lose stability

Images