Control of Active Mobile Substations under system faults

While conventional mobile substations are used to bypass the whole substation in case of loss or maintenance of power transformers, Active Mobile Substations (AMS) can be used both in normal conditions as a power router and in contingencies as a recovery transformer. The AMS is a mobile substation with integrated power electronics. By controlling its throughput power, it can be connected across different transformers of the grid. This paper explores transmission-level active mobile substations that provide back-up in case of power transformer failure or forced reduced operation scenarios in addition to power flow control for seasonal renewable energy transmission. The AMS must be designed to operate satisfactorily under typical fault and unbalanced conditions. In this paper, component design considerations in development of the AMS under unbalanced operating condition will be provided, and a new control strategy is proposed to control AMS under unbalanced operating conditions when component design is not sufficient to prevent overcurrent and trips. Detailed PSCAD simulation for the proposed control scheme is performed and results are presented. Experimental results are also shown to verify the proposed control method under unbalanced operating conditions.