Reliability Evaluation of a Radial Feeder Configurations by Replacing the Distribution Transformer with the Solid-State Transformer

Abstract

The radial feeder is the most typical power distribution system configuration for distributing power to the consumer through the distribution transformer. Distribution transformers are a key component of power distribution systems, they enable voltage transformation, improve safety, reduce energy losses, enhance network reliability, and facilitate the efficient distribution of electricity to consumers. Due to the lack of their role in balancing loads and integrating renewable energy sources, they must be replaced with an alternate solution for modernizing and optimizing distribution grids. A solid-state transformer (SST) is a power electronic device that, in many ways, may replace a typical distribution transformer (DTR). It also improves controllability and provides a direct current link, making it simple to integrate distributed energy sources on either sides of medium and low voltage. However, reliability is the most important parameter in restricting its applications. Modularity is one of the ways to improve reliability and availability by directly re-routing the power within the modular system. This work investigates the failure rate of a modular SST by determining the number of module units required in SST design based on the available IGBT ratings. Further, the reliability of a radial feeder is evaluated by considering the configuration of a) without AS and with DTRs, b) Without AS and replacement of DTRs with SST, c) With AS and DTRs, and d) With AS and replacement of DTRs with SST.