Research On Computerized Method To Calculate Instantaneous Short Circuit Currents Of Power Systems

The calculation and analysis of instantaneous short circuit currents is an important basis for the planning and design of the electricity equipments and the protections' reasonable installation and setting and etc. The traditional operational curve-based method for instantaneous short circuit currents of power systems is still commonly used, which takes much labor with lower accurate results. Based on the relative theories about electric circuit and synchronous generators' post-fault transient, a practical computerized method making use of node impedance matrix is proposed to calculate the instantaneous currents of a faulty power system. Compared with the traditional curve-based method, this method can calculate the currents with high accuracy and little user effort. It can automatically calculate the periodic components of varying short circuit currents at anytime, and the aperiodic components of the symmetric short circuit currents. Also, a calculation model for instantaneous branch current is proposed, and is verified by examples. Che Lizhi(Power System and Its Automation) Directed by prof. Zhu Yongli...