Controller Design and Implementation of DFIG Wind Integrated VSC-HVDC System with Bridge Type Fault Current Limiters

Industrialization and technological advancement have raised the increase in power demand all around the world. Due to limited reserve of fossil fuels, it is urgent to investigate alternative energy resource and to develop new methodology for harvesting energy from renewable sources. Among different renewable sources, wind is fastest growing and most promising for generating electric power due to its zero fuel cost, no carbon emission, and lesser maintenance. However, wind is intermittent in nature. Integration of wind energy with variable speed wind generators requires complicated control techniques. Among different generators, doubly fed induction generator (DFIG) is the best option of wind energy integration due to possibility to cover wide range of wind speed. Fault ride through capability and transient stability are major concerns of doubly fed induction generator (DFIG) based wind energy integration with voltage source converter high voltage DC (VSC-HVDC) system. Since the stator of DFIG is directly connected to gird, it is readily affected by different types of fault at grid side. However, according to grid code requirements, wind generator should stay connected and continue its operation during grid side fault. Fault current limiters (FCLs) are extensively applied in power system to suppress fault current and to improve transient stability as well as fault ride through (FRT) capability of power system. However, their application in VSC-HVDC system needs to investigate comprehensively. In this project, bridge fault current limiter (BFCL) to suppress fault current of DFIG based VSC-HVDC system and improve the system transient stability as well as FRT capability is proposed. The work in this project entails four main phases. In the first phase, a comprehensive literature review on fault current limiters and the latest techniques to control VSC-HVDC system will be conducted. In the second phase, the DFIG based VSC-HVDC system modeling including BFCL will be developed and a novel control strategy that can improve transient stability and FRT capability of the system will be proposed. The third phase of the project will focus on building a laboratory prototype and implementing the developed control strategies using real-time digital simulator. Running necessary experimental work to validate the proposed controllers will be carried out in the fourth phase. In addition, the developed prototype system will help in building research capacity in the area of renewable energy and HVDC, which is of major importance in the Kingdom of Saudi Arabia 2030 vision. The project will be completed within 30 calendar months at a total cost of 75,000 USD, approximately.