Operating strategies for congestion management of HV lines using NaS batteries

The sudden development of distributed generation from renewable energy sources, mainly windfarms, can cause congestions on the existing transmission grids. Due to the difficult authorization procedure for the construction of HV overhead lines, or even for the refurbishment of the existing ones, Battery Energy Storage Systems (BESS) can be an useful solution to local congestions. NaS batteries are the most mature and widespread solution for energy-intensive BESS, due to their relatively low cost and long lifecycle. However due to the high operating temperature, their efficiency decreases in case of low utilization. The present paper deals with NaS battery operation for congestion management, showing that the choice of a correct operating strategy can generate significantly larger benefits for the electrical system.