Research On Security And Stability Control Technology For Ioslated Grid System

When isolated grid system operates, due to the small number of its units, the small capacity of the units and the bad stability of the system, fault conditions often cause substantial fluctuations of system frequency, which even causes unit trip, blackout,and serious damage. Aiming at the China Power Investment Group Mongolian East Energy Corporation Huomei Hongjun Aluminum and Power Company’s isolated grid, this paper conducted a study on system security and stability control technology.First, the paper described the network structure, protection configuration, security and stability control configuration and co-ordination with other relevant professional of the isolated grid.Secondly, the paper conducted calculation and analysis of the system stable situation when line failure, the thermal power unit failure, wind power stopping or qualifying failure sending wind power and electrolytic aluminum load failure happened respectively under different wind power injection situation. The paper summarized the results and found that failure always leads to the frequency instability problems. The reason affecting the isolated grid frequency instability is thought to be the imbalance of the power absorbed by the power emitted by thermal power units and wind turbines and electrolytic aluminum load.Finally, the paperdescribed the frequency characteristics of the isolated grid operation and analysed frequency stability control measures,such as the primary frequency regulation, the secondary frequency regulation, high frequency units shedding and under frequency load shedding.