Upgrading of EHV sub-stations for additional bays and power handling Valecha D.K., Srivastava Rajil, Karma Dinesh K, Mishra Sandip Power Grid Corporation of India Limited Online published on 30 May, 2021. Abstract Indian Power system is expanding and demand is increasing day by day. In this scenario, the capacities of existing substations are exhausted. But at the same time it is also very difficult to build additional substations. To cater the additional load and power handling in existing sub-station, it is required to consider the alternate technology wherein the extension of sub-station may be taken up without affecting much the existing power supply and evacuation of power. Recently, POWERGRID has been entrusted to augment the existing Air Insulated sub-stations with single and transfer bus schemes to double bus schemes by converting the existing station to Gas Insulated Station and by providing additional transformers in addition to augment the capacity of existing transformers to deliver additional power to the customers. The work under various sub-stations involved is as under: • Provision of 6 Nos. additional bays in Gas Insulated Switchgear but existing bays remain Air Insulated in a 400 kV Sub-station in North India and North East India. • Converting 132 kV Single main and Transfer bus scheme in old existing station and addition of additional bays by converting Air Insulated switchgears to Gas Insulated Switchgear. • Creating 400 kV Gas Insulated Switchyard in existing yard 400 kV Yard in addition to augmenting 400/220 kV Transformer the capacity and provision of additional transformer. The challenges under this task are: • Power supply disruption needs to be minimum. • Very limited working space. • No additional space is available. • All the construction is to be under taken in charged yard which requires stringent safety considerations during construction. • All existing protection and control to be replaced with new state of art control and protection system. These upgrading works are under various stages. In some stations the work is in final stages which some are already charged. In some sub-stations, engineering activities just started. The paper will describe one of each typical case, issues faced during execution and how those issues are settled. Top Keywords Upgrading, Gas Insulated Switchgear (GIS), Enhance Power Handling, Augumentation, Extension. Top |