Reliability of Decentralized Network Automation Systems and Impacts on Distribution Network Reliability

Due to the growth of distributed generation and the changes of consumption behavior (e. g. induced by electromobility), the need for cost-efficient and reliable smart grid technologies in medium and low-voltage networks increases. A decentralized network automation system is a smart grid technology that relies on comprehensive information and communication technologies. This enables the monitoring of a network state in real time and the subsequent control of active network participants (e. g. distributed generators) in critical situations. When making an investment decision, it is crucial to assess the reliability of this system and to evaluate the impact on distribution network reliability. In order to be able to assess the reliability of these systems, the reliability analysis is enhanced by the specifications of information and communication technologies. In this contribution, the analytical method of minimal cut sets is used for this purpose. As a result, the state probabilities and transition rates of the presented three-state Markov model for decentralized network automation systems are determined. Moreover, the reliability calculation of an electrical power system is enhanced by the functionalities of a decentralized network automation system. This includes power curtailment, fault detection, fault isolation and recovery techniques. The resulting impacts of these enhancements on customer- and distributed-generator-oriented reliability indices are illustrated and discussed for an exemplary medium-voltage network.