ANALYSIS OF PROTECTION SCHEME OF 33 kV AUXILIARY RING NETWORK IN DELHI METRO RAIL CORPORATION TO ENHANCE SYSTEM PERFORMANCE

Abstract

The objective of any proper protection scheme is to keep the power system stable and reliable by isolating only the components that are experiencing fault while leaving as much of the electrical network as possible still in operation. Major components of any protection systems are instrument transformers, relays, circuit breakers and sometimes communication channel. With the rapid progress in technology, this aspect of electrical engineering applications have become very specialized and now most of the electrical organizations have dedicated teams specializing in this aspect with dedicated softwares for iteration of complex electrical network. Rail based mass transit system are gaining popularity in the country due to the punctuality, comfort and ease of travel provided to the consumers. In this backdrop, the importance of reliable power supply becomes very important. To ensure reliable supply for passengers safety and comfort, planned redundancies in the electrical network, selective and quick protection scheme are very essential for restoring power supply within the stipulated time frame in case of any incident. This dissertation briefly presents the introduction to the system of auxiliary power distribution in Delhi Metro Rail Corporation, analyses the Protection scheme of 33 kV Auxiliary system ring feeders and suggests tripping logics to improve system performance during various fault scenarios. The tripping logics not only help in eliminating the previous drawbacks but also help in quick identification of faulty section resulting in timely resumption of supply from the various planned redundancies. This tripping logic can also prove to be useful in any interconnected ring network or a micro grid which is currently the future of electrical distribution network in many countries.