Voltage control in distribution systems as a limitation of the hosting capacity for distributed energy resources

Abstract

The hosting capacity for distributed energy resources (DER) identifies the acceptable degree of DER penetration under given circumstances. It depends on various parameters such as the characteristics of the generation units, the configuration and operation of the network, the requirements of the loads as well as national and regional requirements. To determine the hosting capacity and to find ways to expand it by overcoming existing barriers is one subject of the ongoing European research project EU-DEEP. This paper describes the impacts of non-controlled DER units on the resulting voltage profiles as these impacts showed to be a main limitation for the hosting capacity for DER in existing distribution networks. The methodology for the analysis is introduced and basic results of the case studies performed are demonstrated. Generally the hosting capacity for DER can be extended applying different technical measures all leading to additional investments into the network. In future active distributions networks will provide a cost-effective solution to increase DER penetration. IMPACT OF DER ON VOLTAGE PROFILE Voltage control in existing distribution systems is based on radial power flows from the substation to the loads and on the fact that real power magnitude decreases with increasing distance from the substation. But, the introduction of DER in distribution systems impacts the methods of voltage control. DER may change the direction of power flows. This may lead to a reduced performance of the voltage control. It remains required that the system operates with adequate security and within statutory limits,. despite the fact that the Distribution System Operator (DSO) does not exert control over the generation..

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