Distributed generation support for voltage regulation: An adaptive approach

• We propose a novel methodology to deal with distributed generation (DG) dispatch in distribution networks.
• DG dispatch can be better dealt with by adapting the active and reactive power from the DG unit to the changing operating conditions of the network.
• An online identification scheme of the Thevenin equivalent circuit is implemented in order to compute the amounts of active and reactive power dispatch values from the DG unit while maintaining voltage levels at specified values.

Distributed generation is expected to introduce additional issues in the operation of distribution networks. Among these, voltage variation is of particular concern and needs to be addressed concisely. Conventionally, voltage regulators are placed in transmission level, where they use reactive power control to alter voltage levels. This approach has been particularly effective due to the inductive nature of transmission networks. However, seen from that point of view, distribution networks are different. Hence, this paper introduces a new methodology to address the problem of DG units dispatch while maintaining voltage levels within desired levels. This approach, termed identification-based adaptive voltage regulation (I-BAVR), uses real-time identification of the Thevenin equivalent circuit of the system, giving the X/R ratio to identify the active and reactive power dispatch of the DG unit. The I-BAVR approach has been validated though several steady-state and dynamic simulation scenarios on a typical medium voltage network. These simulations show that by using an appropriate control strategy, DG can regulate the voltage to the specified levels by adapting the amounts of it active and reactive power to the systems operational changes.