Research on coordination control strategies between generators and outward power grid

Research status of arts in the domain of coordination control between generators and power grid is summarized first, there are four main problems in the domain: setting values of protections related to power grid in power plant and their coordination with power grid, new requirement of peak regulation and frequency regulation technologies for coping with power fluctuation of centralized new energy or wind power generators trip-off, fast tracing source and control of low frequency oscillation, evaluation of subsynchronous oscillation resulted from application of new technologies such as power electronic technology etc. In an outward power grid, some problems such as over-frequency or power oscillation are often occupied after the failure connection between district grid and main grid. The main causes of over-frequency or power oscillation are analyzed, the effect and influence on generator and power grid of four main methods of decreasing output power are described, and then, these coordination control strategies such as to regulate setting values of protections online, to optimize Over-speed Protection Control (OPC) operation mode of thermal power units, to release lower amplitude of primary frequency regulation and to improve functions of Automatic Generation Control (AGC) are studied. A simulation case based on single machine infinite bus (SMIB) power system and PSD-BPA software is constructed. The calculation result shows these coordination control strategies are efficient, they are helpful to stabilize frequency of isolated grid fast, to heighten efficiency of generator, to improve the margin of high-frequency and reliability of power distribution.