Hasanzadeh - High Voltage Laboratory School of Electrical and Computer Engineering University of Tehran Tehran Regional Electric Company
Sheikhghomi - High Voltage Laboratory School of Electrical and Computer Engineering University of Tehran Tehran Regional Electric Company
Pahlevani - High Voltage Laboratory School of Electrical and Computer Engineering University of Tehran Tehran Regional Electric Company

Because of increased steepness of the Transient Recovery Voltage, interruption of short-line faults is the most severe task for almost all high voltage circuit breakers. On the other hand, to determine the black box models of the circuit breakers, the voltage and current measurements during high current interruption tests are normally used. In this paper, different black-box models for circuit breakers are used to study short-line fault (SLF). Parameters of different black-box models are estimated based on the measurements. The implemented models are used to simulate the faults occurring near the circuit breaker terminals (short line faults). The critical length of the line is determined. The results indicate that the interrupting capability of the circuit breaker is enhanced when the shunt capacitor at the line side is increased. As a concrete case, a part of the Tehran electricity network is considered; the evaluations indicate that the circuit breakers utilized in the considered network can clear all possible faults.

black-box model, critical line length, EMTP, short-line fault