Wei Linjun

Research on offshore wind farm VSC-HVDC transmission system fault ride through issue

With the development of power electronics technology, VSC-HVDC has been applied in some offshore wind farm integration projects in Europe by IGBTs and PWM control technology. At the same time, a lot of works have been done on wind farm AC integration fault ride through, and certain results have been achieved, but offshore wind farm DC integration fault ride through issue needs to be studied deeply. The paper focus on offshore wind farm VSC-HVDC transmission system fault ride through. Based on AC and DC wind energy integration stability influence analysis, compared the different integration mode technology characteristics, the main stability influence factors of DC integration will be given. Then the offshore wind farm VSC-HVDC transmission system fault ride through scheme is studied according to the wind farm capacity. Chopper and wind turbine coordinated control scheme will be adopted to provide dynamic reactive support on the basis of the system meeting the requirements of the fault ride through. Finally, a practical example is done to verify the correctness and effectiveness of the proposed scheme.

Study on LVRT capability of D-PMSG based wind turbine

Wind power in China is experiencing rapid development in recent years, and problems come forth due to the grid connection of large-scale wind power. Based on the status of wind power development in China, necessity of wind farm low voltage ride through (LVRT) capability is studied in this paper. The strategy for LVRT realization of D-PMSG based wind turbine is presented by studying the control system of wind turbine, and the control processes during LVRT period is showed. A study case is given to show the impact on power grid when wind farm is with or without LVRT capability and also to show the validity of LVRT models and control system presented in the paper.

Study on the driving force and challenges of developing power grid with high penetration of renewable energy

With the increase of energy demand and environmental awareness, It becomes an inexorable trend to develop and utilize renewable energy and to increase the proportion of clean energy in end use energy. The development of power grid in future should not only consider power demand but also accommodate large-scale renewable energy. This paper conducts a study on the development pattern of future power grid including high penetration of renewable energy. The driving force of developing power grid is analyzed though deducting its development process and exploring potential and dominant factor by using the experiences of European countries and USA for reference. Based on the above work, the requirement and challenges of future power grid are explored considering the specific characteristics of power grid development in China, and the key technical problems is figured out. Finally, potential development scenarios are presented regarding future power grid of China.

Research on market mechanism of wind power accommodation based on power bidding

With development of smart grid and enhancement of wind power integration technology, competition mechanism, gradually introduced into the power market in China, will provide convincing external environment for the wind power accommodation. Wind power accommodation mechanism based on power bidding is presented, as well as accommodation analysis model and calculation method are put forward in this paper. Firstly, feed-in tariff of wind power is declared by wind farms according to operating cost and economic performance, then wind farms are arranged according to costs from low to high order, then dispatching schedule and commitment of wind farms are formulated based on the principle of minimum purchase cost. Finally, wind power accommodation space is calculated by using continuous time series production simulation method. Consequently, the impartial and open power dispatching principle is held to realize priority dispatching under the situation of a provincial power market and system peak regulation capabilities. In the environment of power market, reasonable and effective power bidding will be significant for wind power benefit and will provide referenced frames for practical operation of power bidding.

Study on developing scale of wind power and its layout of regional power grid

Due to the operating characteristics different from conventional power plants, the grid connection of large-scale wind power will inevitably cause much impact on power grid. Thus, the developing scale in region level and the reliable grid connection of wind power become key issues to be considered. The study in this paper will focus on the developing scale of wind power of regional power grid, and the layout and location of wind farms will be analyzed based on the above results. Firstly, the accommodation capability of power grid will be analyzed from power balancing consideration, and the developing scale of wind power will be determined consequently. Based on the above analysis, the impact of wind farm on busbar voltage will be studied through sensitivity analysis considering the reactive power characteristics of wind farm, and the reasonable capacity of wind farm connected to each busbar will be explored. Finally, a transient stability analysis will be conducted after the grid connection of large-scale wind power into power system, and suggestions on the planning layout of wind power will be given considering the transmission capability constraints of power grid.