Parameterising Local Reactive Power Control Characteristics of Distributed Energy Resources Through Time Series Based Optimal Power Flow Calculations

Abstract

This paper presents a method for determining local reactive power control characteristics for distributed energy resources. Based on historical time series, an optimal reactive power dispatch is calculated. The optimal reactive power dispatch minimises a multi-criteria objective function that allows the reduction of grid losses while complying with a desired vertical reactive power exchange with the overlaid grid and with operational constraints. From the resulting optimal operating points, individual reactive power control characteristics can be determined by piecewise linear regression and then be clustered to reduce the complexity of the grid planning process. The method thus allows the integration of the information contained in the historical time series on the volatile power flow behaviour and offers the possibility of systematic parameter determination. In contrast, conventional grid planning uses empirical values or conservative estimates. In contrast to offline or online optimisations during operation; however, no real-time capable information and communication infrastructure is required. To validate the performance of the method, operation with the cluster control characteristics is compared with offline optimisation and simple parameterisation approaches for local reactive power control characteristics.