Cui Xiaodan

Research on the influence of fault current limiters on commutation failure and transient stability in AC/DC power system

In this paper, the method of installing fault current limiters (FCLs) near DC converter station is proposed, which is aimed at the commutation failure caused by short circuit fault of the DC inverter side in AC/DC power system. Influence mechanism of FCLs on suppressing commutation failure is analyzed. Whats more, effects of FCLs in different locations on commutation failure are compared. In addition, theoretical analysis of transient stability on multiple high voltage direct current (HVDC) commutation failure system with FCLs is discussed using the extended equal area criterion (EEAC) theory. Finally, simulation is carried out based on an actual power grid. Theoretical and simulation results show that, the action of FCLs can not only limit the short-circuit current, but also effectively suppress commutation failure and alleviate the power imbalance and the transferred system flow caused by the concurrent commutation failures, which can significantly decrease the power impact of the regional section and improve the transient stability of the system.

Effects of fault current limiter on the safety and stability of power grid and its application: A research review

In this paper, basic principles, advantages and disadvantages, development and applications of different types of fault current limiter (FCL) are described. Effects on safety and stability of power grid and optimization configuration are also expounded with the application of FCL in aspects of relay protection, reclosure, transient power angle and voltage stability. In addition, several key problems of FCL engineering application are summarized. The development trends of FCL research and application are also proposed. It points out that FCL will play a unique role in fields such as improving the transmission capacity of DC Receiving-side, reducing the risk of commutation failure, improving power quality, enhancing large-scale new energy integration capability and so on. Due to the limitation of technical and economic constraints, economical FCL based on the normal electric equipment is still the first choice for application at present. However, with the increasing maturity of large-capacity and high-voltage self-turn-off power electronic devices, solid-state current limiter based on power electronic technology will become the research and application hotspot in the future.

Parameters optimization of excitation system based on extended Heffron-Philips model

Control mode and control parameters of the excitation system play an important role in the security and stability operation of generator and even power grid. It is shown in some generator oscillation accidents without system fault in industrial enterprises that there have exciter stability problems in industrial power plants. In this paper, an extended Heffron-Philips model considering Var and power factor excitation system was established to analyze such the excitation system stability problem. And then with the system characteristics matrix system characteristics root will be carried out to study the principle factors on excitation system stability. A parameter optimal method for excitation system considering local power system small signal stability was proposed based on system root locus. The mechanism of abnormal oscillation without system fault occurred in actual industrial power grid was analyzed and the excitation control parameter was redesigned using the proposed method, which was verified by simulation results.