Shi Dongyuan

Comparison of superconducting fault current limiter in power system

Due to its ideal electrical behavior, the superconducting fault current limiter (SFCL) has become one of the most important development trends of limiters in power systems. This paper summarizes the main electrical behaviors of SFCL, including the relationship between SFCLs working current and the quench current of the superconducting coil (SC), and the relationship between equivalent fundamental frequency impedance of SFCL and normal state resistance of SC. Operation losses and response time of SFCL are also discussed. The paper analyzes different influences of quench type SFCL and nonquench type SFCL on waveforms and total harmonic distortion (THD) of line current and node measurement impedance. Electromagnetic simulation is adopted to analyze the characteristics of the SFCL.

Road to the integrated protective relaying fault information system

This paper introduces an integrated power system protective relaying fault information system. This system interconnects several vital substations to take the protective relaying and fault recorder under control, so the real-time supervision of them and integrative analysis can be carried out. It has been installed in the State Power Corporation of China and is now under test-run. At the same time, in this paper, it is proposed to integrate fault information system with other applications related to protective relaying to form a uniform platform for the operation and analysis of protective relaying. And the further development of this system in the near future is put forward.

An integrated power system relay coordination software

The development of new generation software for relay coordination is the focus of the relay protection industry and related research fields. In this paper, an integrated power system coordination tools called Computer Aided Coordination for Relay in Power System with Graphical Interface is presented. A brief description of the development of setting tools is given first, then the whole structure and function division are introduced. Finally, the new tendency of relay coordination software is put forward.

A study on optimal coordination of definite-time relay based on genetic algorithm

Relay optimal coordination is of great significance in bringing the role of the protection device into full play, improving the integral performance and ensuring the best integral effect of the protection system. In view of the problems existing in optimal coordination of definite-time relay, this paper presents a new method based on the genetic algorithm. In this method, a new coding technique, called constraint interval coding, is adopted to enhancing the efficiency and precision of optimization. The result of an example shows that the new method is effective for optimal coordination of definite-time relay. The application of the new method in the multi-loop network and the mixed protection system with inverse-time relay and definite-time relay is discussed further.

A study on the simple loop formation method of modern power system

Formation of all simple loops is a pivotal step of influencing the efficiency of break point determination algorithm. In view of the characteristics of modern power network loop distribution, based on the method of fundamental loop linear combination, a new simple loop formation method is presented in this paper in which combining a formed simple loop or complex loop with a fundamental loop can form a new simple loop. The new method can not only eliminate most invalid loop combination, but also decrease calculation quantities. The result shows the effectiveness of the new method.