Research on optimization of generation cutting strategies for thermal and wind generations building energy bases

摘要

In response to the worsening of the environment caused by large consumption of fossil energy, the development and utilization of renewable energy has been the focus of people's attention. As an important form of renewable energy, the electricity generated by the wind has received more and more attention. Due to the highly concentration of wind power resources in some remote areas and the lower local load consumption level, the large-scale wind power must be transmitted to distant load centers through the main grid in China State Grid, which is markedly different to the other countries. In order to reduce the unpredictable volatility and enhance the using efficiency of wind power, the large capacity thermal and wind generations bundling energy bases are built and operated. So, some new security and stability problems occurs. Under some severe fault circumstances, only thermal generation tripping cannot guarantee the power system to restore stable or cost excessively. This paper presents a prescription for the optimal proportion strategies of thermal and wind generations in security and stability control measures, which can minimize the cutting capacity of thermal and wind generations and maximize the economic benefits. First, the difference of transient characteristics between wind turbine generator and conventional thermal generator is studied to distinguish their respective impacts on accelerating power of sending power system. Second, transient stability performance of Wind and Thermal Bundling System is analized to ensure that the impact on stability of large scale wind generator don't been ignored. Third, optimization strategies and programs of thermal and wind generator tripping based on transient energy function in shown, and it can estimate the stability of thermal and wind generation bundling energy base and single thermal generation to decide the tripping capacity of thermal generator; meanwhile the transfer capacity of tie lines after faults is calculated to decide the tripping capacity of wind generator which is drastically reduced by faults. Finally, the results based on real thermal and wind generation bundling energy base of Northwest China Grid show that the optimization strategies can significantly reduce the tripping amounts that guarantee the power system to restore stability, improving recovery characteristic after severe fault, greatly increasing the safety and economy of the thermal and wind generation bundling energy base.