Performance Evaluation of Tarbela Power Station for Improving Operational Efficiency and Reliability using Modern Techniques

Abstract

Tarbela Dam is the largest earth filled dam in the world. Tarbela Power Station is the largest Hydro Power Plant in Pakistan with current installed capacity of 3478 MW with a 1410 MW Tarbela-IV Extension that is underway to increase this capacity to 4888 MW. The alarming power crisis in the country warrants maintaining high efficiency, reliability and availability of Tarbela Power Plant and its generating units in particular with minimum forced outages and equipment failure. In this research we have covered detail analysis of the main equipment, performance evaluation and efficiency of installed plant equipment e.g. Generator protection relays, Generator Excitation and Governor System and other allied equipment by using plant data and different softwares. Particularly, response of newly installed digital governor through Toolbox ST software, Excitation System through Winoper (SCADA) software and Protective relay of Tarbela Power Station through OMICRON test set were analyzed. During testing different parameters like speed of the Hydro generator after load rejection, step response of MW, Speed, wicket gate and relief valve timing are checked and comparison of previous installed Electromechanical Governor is also illustrated. As generator is the most expensive part of the plant, hence performance evaluation of generator protection system is to ensure the proper and smooth functioning of the Power plant is also included. We investigate different generator auxiliaries faults of the machines causing prolong force outage and their remedial measures. Power stations nowadays require new state of the art system which stands for high availability as well as efficiency, robustness, high mean time between failures, and an estimated lifetime of about 25 years or more. To date, no foreseen study worth mentioning has yet been carried out in focusing on improving operational efficiency and reliability of the largest dam in the world and other existing Hydroelectric Power Plants in Pakistan. It is anticipated that this research can become a step for running and updating other Hydro Power Plants in an effective manner where importance is given to the upgradation of inefficient existing obsolete equipments enabling efficient, reliable operation and prediction of plants performance curve throughout the years.