Over-voltage mitigation within distribution networks with a high renewable distributed generation penetration

The rapid growth of grid-connected distributed generation has increased the likelihood of over-voltage occurrences in distribution networks. In recent times, much research has taken place in order to develop a control strategy to mitigate the voltage rise problem. However, most of the published strategies require re-tuning when additional resources are connected, or have a strong dependence on network parameters, such as fault level. This paper proposes a novel over-voltage mitigation scheme that has many advantages not observed in literature. Firstly, the control scheme can integrate with an existing feeder in a plug-and-play fashion. No prior analysis is necessary to configure the control parameters; all required information is measured locally. Secondly, the control scheme is a simple extension upon constant power control which is common in most grid-connected inverter interfaces. Finally, the proposed over-voltage mitigation scheme enforces a fair and equitable power flow allocation. The scheme contains a predefined point of convergence for any voltage magnitude measured at the point of common coupling. Many control schemes operate in a perturb and observe manner which can inadvertently allow certain DG units to export a disproportionate amount of power with respect to other DG units. This paper also details a methodology for analysing the cost effectiveness of any given DG configuration utilising the proposed over-voltage mitigation scheme. The analysis is useful for determining whether a network infrastructure upgrade may be necessary as power curtailment becomes more prevalent within a distribution network.