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It is necessary to evaluate the reliability of the system's operation after grid-connected offshore wind power, to comprehensively evaluate and further improve the reliability of the grid including the receiving end of offshore wind power, which is beneficial the receiving power grid with large-scale offshore wind power runs safely and stably. Improve the power supply reliability of the offshore wind power receiving terminal. Considering the harsh operating conditions of offshore wind power, the frequent occurrence of extremely bad weather such as typhoons on the eastern coast, and the mutual influence of certain situations are frequent and involve a wide range, which brings serious harm to the offshore wind power connect system. At the same time, offshore wind power maintenance has poor accessibility, high maintenance costs, and reduced the reliability level of offshore wind power systems. In addition, when offshore wind power is connected to the receiving power grid through a combination of high-voltage AC and DC, it will have complex interactions with multi-level AC and multi-type DC external incoming calls, which may expand the scope and depth of the fault. Therefore, it is necessary to take into account the effects of severe weather at sea, offshore wind power maintenance plans, and various complex interactions to conduct a more comprehensive and in-depth study of the reliability assessment of offshore wind power connect to the power grid.

Typhoon disaster can result in wind farms shutdown. With the large-scale integration of wind farms in power system, the wind farms shutdown may affect the operation of power system, causing the power shortage and voltage violation. In this paper, a shutdown risk assessment method is proposed to evaluate the risk of wind farms operation under typhoon disaster. Firstly, the distribution of forecast error of wind power under typhoon conditions is analyzed according to the historical data and is established as T distribution. Next, the real-time shutdown probability of wind farms is generated by the known cumulative error distribution. Then, the shutdown cost of wind farms are expressed by the cost of shedding load after wind power exiting, which is solved by particle swarm optimization method. Finally, the adjusted IEEE-33 node system with wind farms are adopted to verify the effectiveness of proposed method.

Most of the small-size hydropower stations are runoff hydropower stations and their output is determined by the upstream water supply. Consequently, the rainfall brought by typhoons will lead to the increment of runoff, increasing the output of small-size hydropower stations. The uncertain increment of the output of small-size hydropower stations will bring adverse effects on the security of power system, such as the voltage over-limit and the power overload of transmission lines. In this paper, a risk assessment method is proposed to assess the shutdown risk of small-size hydropower station under typhoon disaster. Firstly, Monte Carlo Method is employed to calculate the probabilistic load flow of power system with small-size hydropower station and the probability of node voltage over-limit and branch power overload is set to be the shutdown probability of small-size hydropower station. Secondly, the cost of load shedding which is optimized by Adaptive Particle Swarm optimization (APSO) algorithm is set to be the shutdown cost of small-size hydropower station. Finally, the IEEE-33 bus system is used to assess the shutdown risk of small-size hydropower station under typhoon disaster.

In order to analyze interaction between wind farm and electric power system, research transient voltage characteristics of large-scale wind farm in system fault and after fault, and realize large-scale wind farm fault ride through, it is necessary to build wind turbine modeling suitable for large electric power system simulating calculation program. Various power system simulators are used in many research institutes and power operators home and abroad, and there are different processing methods for wind turbines and wind farms modeling designed for different research purposes, as well as different running characteristics with different wind turbine manufacturers and technical specifications, so whole process simulation under multiple working conditions shall be realized by carrying out corresponding work. Based on basic theory of wind power generation, this paper analyzes structure and characteristics of double fed induction generator (DFIG), researches models of its mechanical system, electric system and other main constituents, and gives basic requirements and characteristic simulation of wind turbine modeling with transient response characteristics under multiple working conditions.