Hybrid Grid for enhancing capacity of AIS substations with space limitation with use of GIS switchgear

Primary Distribution Substations (PDS) in our area of operation. In already developed urban areas, land owning agencies, are unable to provide land for new substations, necessitating capacity addition in existing substations. Thus, it is required to utilize the existing substation to maximize both transformation capacity as well as accommodating new lines. Most existing substations are outdoor Air Insulated Switchgear (AIS) type. Here capacity addition becomes a challenge where there is no space to add new bays in the switchyard to add new transformer or line. In this paper we present the case where there was requirement to add a new line to an existing

PDS where there was no space for addition of a new bay. This was required to provide supply to a new bulk consumer at 66 kV to feed an electric bus charging station. In section 1, the challenges in general and in section 2 those specific to the case are discussed. Multiple possibilities were explored but were deemed not suitable considering either cost or ease of implementation. These include supplying from an alternate source station, remodelling the existing substation as a Gas Insulated Substation, etc. Section 3 covers the exploration of these option. Finally, a solution for a hybrid AIS and Gas Insulated Switchgear (GIS) switchyard design was finalized which offered the least cost and ease of implementation. This solution was implementable in the existing switchyard space itself. The solution is discussed in section 3.5 of the paper

Post conceptualization of the solution, meetings were conducted with multiple Original

Equipment Manufacturer (OEM) regarding the technical feasibility of the solution. The required solution or customization of GIS panel was found to be feasible and the same was implemented.

In Addition to solving the present problem, this solution could be implemented across all existing AIS substations of similar design with space constraints issue for installation of additional Power Transformer or addition of new lines. This is explained in Section 4.