The determination of the transient stability of an electric power system is a crucial step in power system analysis. This paper investigates the transient stability of an IEEE-9 bus system consisting of three generators and nine buses. At first, a load flow analysis is conducted in order to determine the pre-fault conditions. Secondly, fault analysis is performed to analyze post fault conditions like the fast fault clearing time and load switching in order to determine the system stability. For transient stability analysis, Euler and Runga methods are compared and applied on the frequency and rotor angle of the system to analyze the system variations under different fault conditions. The simulations were done on the Power World Simulator (PWS) software. It is concluded that Critical Fault Clearing Time (CFCT) is a very important factor in keeping the power system within the stability bounds. A slight increase in Clearing Time (CT) from the critical value causes un-synchronism.

Nowadays power demands are continuously increasing and the biggest challenge is to provide stable voltage to consumers under different load conditions. The fluctuation in nominal voltage values affect the performance of attached load. Voltage Stabilizer is a device, which is used to balance the voltages under changing load conditions. However, conventional voltage stabilizers have slow transient response with additional problem of sparking resulting from electromechanical relays. These problems are eliminated using TRIAC based automatic voltage stabilizer. Moreover, these also provide over voltage protection, overload protection and short circuit protection. TRIACs are utilized as switching devices with comparable number of transformer taps. In this research paper, a TRIAC based automatic voltage stabilizer is simulated in Proteus and then designed and implemented using PIC microcontroller. The problems of slow transient response with high sparking of relays in conventional voltage stabilizer have been successfully compensated using TRIAC based automatic voltage stabilizer. The experimental results verify the clam of high quality performance of TRIAC based automatic voltage stabilizer.