本指南将考虑AC和DC系统的组成部分，并为正在考虑的变电站设计合适的系统提供指导和建议。本指南涵盖从电源到配电点的低压辅助系统。讨论了可靠性要求和负载特性，并推荐了分配方法。

This guide will consider the components of both the ac and dc systems and provide guidelines and recommendation for designing the appropriate systems for the substation under consideration. This guide covers the low voltage auxiliary systems from the source(s) to the distribution point(s). Reliability requirements and load characteristics are discussed and distribution methods are recommended.