Reliability Analysis Of AC/UHVDC Power System With Wind Power And Security And Stability Control System

With the large-scale wind connected to the power system and the operation of "Jiang Dian Dong Song" project,the voltage grade of UHVDC line is getting higher and higher,and the transmission capacity is getting larger and larger.Once the random outage of the UHVDC system happens,the safe and reliable operation of AC power grid will be seriously threatened.As the second or even the third line of AC/DC power system,the reliability of the safety and stability control system is facing the great challenge.In this paper,the AC/UHVDC system with wind power and the safety and stability control system are taken as the research objects.The reliability evaluation and sensitivity analysis of the two systems are studied.The main innovations are as follows:(1)Considering the detailed structure of the doubly-fed induction generators(DFIGs),the power flow is calculated,and the multi-state model of wind power can be established.The concept of state transition power was proposed to describe the fluctuation of wind power quantitatively.(2)Based on the DC power adjustment and multi-state model of wind power,the sensitivities of reliability indices to DC power and wind power output are proposed.The causes between DC power,wind power and load shedding cases are proposed.(3)Based on the hierarchical structure,redundant configuration of stations and directional instruction of the frequency stability control system(FSCS),the probabilistic weighted directed graph is put forward.The probabilistic weighted fully matrix is obtained by the path search algorithm.Since the standby master stations(MSs)need the condition before operating,i.e.the primary MSs failures,the topology of the MSs need to be corrected.(4)From the probabilistic weighted fully matrix,the configurational and functional reliability indices are proposed.The former is used to evaluate the probability of the executive stations successfully receiving the instructions from the MSs.The availability of the stations can be assessed.The latter can reflect the ability of the FSCS to guarantee the safe and stable operation of the power system.(5)The analytical model of sensitivities of the reliability indices to the FSCS devices are proposed.The measures used to improve the reliability of the FSCS from itself and the power system can be analyzed.