Reactive Power Management at the T–D Interface by DSO

Abstract:
The increased integration of renewable energy sources (RES), the expansion of underground cable infrastructure, and the increased use of capacitive loads are encountering new operational challenges for transmission system operators (TSOs) and distribution system operators (DSOs). One emerging issue is the reactive power at the transmission-distribution (TD) interface. In the Netherlands, prescribed boundaries are currently being exceeded. This study first analyzes the key factors influencing reactive power flows. It then proposes methodologies for reactive power compensation (sizing and siting) at the DSO level, employing both shunt reactors and market parties (RESs). An optimization problem is formulated with the aim to minimize the costs for the DSO, and also eliminate the reactive power flow from the DSO to the TSO, in line with the Dutch grid code. The proposed gradient-based optimization method is benchmarked against a rule-based approach and an AC optimal power flow (AC-OPF) solution.