Research On Power Reserve Coordination Optimization Technologies Based On Risk Quantification

Reasonable reserve is an indispensable technical means to ensure power grid safety,stability and economic operation.Operation of large-capacity AC-DC transmission channel and integration of large-scale renewable energy sources are increasing the uncertainty of the power system itself.While energy-saving and environmental protection,green dispatching and renewable energy consumption are increasing variability of the power grid's external environment.All of these problems bing many new challenges for the reserve of power system.The emergence of flexible loads provide a new idea for the utility of smart demand side response technology to assist the grid reserve configuration and risky management and control.Based on the idea of risk quantification,coordinated allocation of reserve capacity,direct load participating in primary frequency regulation,flexible load participating in secondary frequency modulation,and coordination optimization of reserve configuration with emergency load shedding are systematically studied in this paper.Firstly,considering the probability and adverse consequences of the accident,as well as the influence of reserve on the power supply reliability,reserve capacity configuration and the risk caused by shortage of reserve capacity are quantified.Indicators reflecting the adverse consequences of the accident are established.Furthermore,reserve configuration scheme evaluation index considering system reliability and economy is considerated additionally.Considering differentiated requirements between system reliability and economy,accident reserve capacity is allocated according to the evaluation result of regional accident reserve risk index.Thus risk quantification based coordinative allocation of emergency reserve is proposed.Results of the case study show that the method can coordinate the allocation of reserve capacity by the regionalization of the reserve capacity,so that the total accident risk of the system can be reasonably eased.Aiming at the lack of system primary reserve capacity,problem of the direct load control participating in primary reserve is studied.Based on the direct load control frequency adjustment coefficient and the generator difference coefficient,the mathematical expression of direct load control and the primary reserve of the generator on the frequency recovery of the system is given.Integrating the probability of active power shortage,the reserve capacity cost,and reliability and economy of the system,the coordination optimization model of direct load control participating inprimary reserve considering the frequency recovery effect is set up and the frequency recovery effect is improved.The operating characteristics of flexible load and the capacity of flexible load participating in the secondary frequency modulation reserve considering comfort degree is analyzed.Based on the quantification of risk,coordination optimization method of generating side and flexible load participating in the secondary frequency modulation reserveconsidering the minimal cost of the system is proposed.Constraints include user comfort,response capacity and number of responses in the model.Results of case study show that this method can improve technical and economic performance of flexible load participating in the system secondary frequency modulation under the premise of its comfort.Aiming at the shortage of system emergency reserve,coordination of the primary and secondary reserve configuration and emergency load shedding is studied in this paper.Combined with the cost of the first,secondary reserve and emergency load shedding,the concept of frequency recovery factor is proposed by considering fault probability and the frequency recovery effect in the dynamic process.The coordinated optimization model is constructed with the minimum optimization objective function of the total cost with static stability and transient stability constraints.The linear programming method can be used to solve the coordination problem of load participating in different time scales reserve with emergency load shedding,so as to achieve the purpose of minimizing the cost of system operation and control.Taking Jiangsu power grid ‘friendly interaction project with source-network-load' practice as the background,the technical and practical feasibility of reserve configuration and coordination is analyzed from the viewpoints of overall function,design thought and system architecture.