Protection performance and operational statistical analysis for Karachi grid

Power system protection is of extreme importance for the reliability and safety of any power system. Karachi Electric Supply Company (KESC) is the sole power supply utility of Karachi, which is the largest industrial and most densely populated city of Pakistan. In this paper, we propose to give an overview of the transmission network of KESC. This would include a review of the network and voltage levels being used for transmission. The geographical area covered, major causes of power loss, fault conditions, respective applied protection schemes being used by KESC for primary and back up protection and the relays installed are discussed. The main factors considered for the selection of breakers and relays under local network conditions are also listed. A comparison of KESC protection philosophy with the applied protection in Quetta Electric Supply Company (QESCO) for the similar zones and faults is presented at the end. (author)