Investigation on transient stability of an industrial network and relevant impact on over-current protection performance

System protection performance and transient stability of the electrical network are significantly affected by each other. The larger the time delay in which protection detects and clears the fault, the more likely loss of synchronism will be, especially in the networks with internal generation. Over current protection schemes inherently operates with considerable delay. Moreover, system dynamic oscillations discernibly aggravate their performance. Therefore utilizing them as main protection is controversial and even abortive in order to maintain system stability. In this paper, transient stability of a real industrial network is studied. The study is investigated using critical clearing time (CCT) criterion for different network configuration. Equipments such as generators and motors are modeled and simulated by DIgSILENT software. In addition, the operation of over current relays adjusted by conventional methods is investigated dynamically and its performance is examined under different network configurations.