Operating experience of regional interconnections in India

That regional interconnections can benefit interconnected grids is accepted by the decision makers owing to optimal utilization of resources, diversity of load patterns, increased security and improved system performance. However, there are "opportunities and threats" depending on how commercial, operational and security issues are tackled. The threats stem from potential seaming problems in the integration and lack of adequate defense mechanisms. In India, five large sized regional grids operate and these are interconnected either synchronously or asynchronously. The operating strategies for interconnections have evolved through trial operations on exiting system which are covered in this paper. The paper overviews the salient features of all the regional interconnections in India. The commercial mechanism, availability based tariff (ABT), adopted by India has facilitated seamless integration on commercial front to a good extent as described in this paper. ABT links part of tariff with a universally available signal of system frequency. From experience gained over last few years, the operational and security issues have been discussed. With open access in operation, the interconnecting corridors have to play a significant role in the operation of the interconnected system. The need for evolving standards for the integrated operation became evident from the experience. The guiding principles for such standardization are also reported in this paper.