93. Criteria for Refurbishment of Protection Systems

The complexity of grid network is increasing day by day with the addition of transmission elements like substations, transmission lines, distribution feeders etc. to meet the ever increasing demand & generation which also require protection systems to match so that the basic criteria of a protection, i.e., associated with the ageing of the equipments like conductors, insulators and other accessories. The combined effect of above is manifold increase in magnitude of fault currents and frequency of the faults. The existing protection systems are not only inadequate to match the present requirement, but the problems have increased due to aging and old & obsolete technology. The main disadvantages of the old relaying systems are: (a) Only MHO characteristic available for distance protection. This fails to clear faults of high resistive nature. (b) Lack of self supervision. Problem in the relays is not indicated, Generation of heat due to higher power consumption leads to premature failure of components. (c) Change in characteristic with passage of time due to aging effect. (d) CT burden requirement is high. (e) No fault data available except phase indication. (f) Power swing feature not reliable. (g) SOTF & other features not available. (h) Speed of operation rather show. It is, therefore, high time to refurbish the protection systems to increase the reliability of the network & reap the benefits of the modern technology numerical protection system to achieve the goal of a flawless relaying system. With this aim in mind, we at GETCO under the dynamic and able leadership of our hon'ble MD Shri S.K. Negi have embarked on this challenging task of refurbishment of protection relaying of the entire GETCO network, which we hope to complete by next 4 to 5 years. With full implementation of the above refurbishment plan, the network of GETCO, will strengthen and will increase the stability of power supply in our region. The stability and security of a grid network assumes a greater significance in the present scenario & any grid network to surve in future open access regime will have to supply uninterrupted quality power to his consumers which will become possible only with a reliable and state of the art relaying system whichwe hope to achieve by the refurbishment under taken by our company.