This paper presents an analytical technique to evaluate the reliability of customers in a microgrid including distributed generations (DGs). Operators of the microgrid are responsible for a reliable energy supply to their customers. Due to the strategy of the priority on their customers, the restoration process of DGs should be reordered when system outage happens. The previous study has proposed the analytical technique to evaluate the reliability of customers in the distribution system that one operator owns all DGs. The proposed method includes photovoltaic (PV) systems and fuses, and the impact factor is modified to obtain the interruption cost. Also, equations are generalized to consider more than one component in a section. Case studies in RBTS Bus 4 verify that the accuracy of the proposed technique is comparable to that of MCS, and the configuration of system divided into several microgrids changes the reliability of customers in the microgrids.

This paper presents an analytical technique for evaluating the reliability of a distribution system, including distributed generation. Unlike the large-scale generation of the transmission system, distributed generation (DG) creates difficulties in evaluating reliability indices due to the complexity of the operation status. Explicit expressions for analyzing the reliability of distributed generation are proposed in this paper. The technique proposed includes the characteristics of DG, such as operation mode to mix peaking and standby modes and the failure of starting and DG itself

This paper introduces an efficient methodology to design optimally cable layout of inner grid as well as location of offshore substation. The methodology is composed of two optimizers: one is inner grid layout optimizer, which consists of several algorithms such as the k-clustering-based genetic algorithm, the minimum spanning tree, and the cable selection; the other one is offshore substation location optimizer based on the pattern search method. While performing iteratively two optimizers, alternatives for cable layout and candidates for location of offshore substation are generated and evaluated in the economic and reliability aspects, respectively. Optimal layout of offshore wind farm is determined so as to minimize the total cost which is a sum of construction, power loss, maintenance, and reliability costs.

Energy storage systems (ESSs) used for ancillary purposes in power systems have different capacities and output characteristics, and so need to be scheduled and operated together based on their state of charge rather than individually. This paper proposes a simple but effective method to allocate the energy required for spinning reserve or frequency regulation, properly to each ESS within a multi-ESS with the aim of improving system reliability. For this, an ESS reliability model is first proposed, and the reliability of the entire system is then evaluated using reliability models for other utilities such as conventional generators and renewable energy sources. To better demonstrate the improvement in reliability, two new reliability indices are introduced besides the existing indices: loss of frequency probability and loss of duration probability. Through case studies, it is shown that the required power is more effectively distributed across each ESS by the allocation method and thus the method can contribute to securing more spinning reserve and alleviating more frequency fluctuation, rather than the conventional method.