For the last two decades increasing attention has been given to Petri net's applications for the representation and analysis of large, complex, distributed, stochastic and discrete-event systems like flexible manufacturing, industrial control systems, communication protocol, distributed-software systems, distributed-database system, multiprocessor memory systems, data flow computing systems, fault-tolerant systems, and computer industries. Since power system is a large geographically wide distributed system, in the recent past, application of Petri net's theory in power systems have also been reported. This article presents literature survey of recent papers published in the area of power systems using Petri nets. Basics of Petri net's theory and its different forms applicable to power systems are also discussed. A method of detecting type of faults on three phase transmission line by using Petri net theory is discussed in details. Different examples based on Petri nets shows that such methodology is more efficient than the traditional approaches especially when the complexity of the problem increases.