Research On Planning Method For Fast Frequency Response Reserve

With the development of large-scale grid-connected and UHV DC transmission networks for renewable energy generation in China and the development of load-side response technologies such as interruptible load and energy storage,the reserve demand of the system in the frequency response phase has also changed.On the one hand,the large-scale grid connection of renewable energy leads to a decrease in the proportion of thermal power generation,which in turn leads to a decrease in the frequency response capability of the power generation side of the system.On the other hand,compared with the traditional accident,the frequently occurring UHV DC blocking accident has a larger power shortage,and the frequency deterioration rate is faster after the accident,and the system frequency response situation is more severe.The traditional alternative structure classification method is simple and rough,and it lacks the emphasis on fast frequency response reserve,and it is difficult to adapt to the complex standby needs in the new situation.In addition,the traditional reserve planning method only considers static frequency index,and cannot calculate the frequency dynamic change process after the accident or be directly used in the fast frequency response reserve planning.Aiming at the problem of the incompatibility of China's original reserve classification method,this paper takes into account both demand and supply side of reserve.The reserve classification system applicable to China's power grid under the new situation is designed.The definition of fast frequency response reserve and the scope of application are clarified,paving the way for research on its planning method.In order to solve the problem of frequency dynamic process for fast frequency response reserve,this paper first analyzes the theoretical requirements involved in and establishes its design idea of the fast frequency response reserve planning method.Based on the Simulink simulation platform,the frequency response model of each component is established to determine the relationship between the reserve capacity,response speed and other factors with the system low-frequency load shedding loss.Based on the traditional cost-benefit analysis method,the sequential Monte Carlo simulation method is used to determine the expected value of the system low-frequency load shedding loss,and a fast frequency response reserve planning method considering the dynamic process of frequency is proposed.In order to consider the risk appetite of decision makers for fast frequency response reserve,a fast frequency response reserve planning method considering conditional reliability is proposed.The optimal conditional spare capacity is dependent on the range of risks that the decision maker is concerned with.The resulting planning results can be verified using the conditional total cost.The modified RTS79 improved system is used to analyze the example.The modified RTS79 improved system is used to analyze the example.The results show that compared with the traditional reserve planning method,the proposed reserve planning method considering the frequency dynamic characteristics can more accurately determine the low-frequency load shedding loss,which is more suitable for the planning problem of fast frequency response reserve.Introducing conditional reliability into the fast-frequency response reserve planning method can not only be compatible with the overall mean-based planning method,but also help decision-makers to plan optimal reserve capacity according to their risk preference and provide an explanation for whether to accept the reserve plan.