本指南涵盖了有助于确保差动继电器、相位继电器和接地继电器极化电路正确连接的测试。尽管本指南中未详细讨论这些准备测试，但本指南中未提及这些测试。

This guide covers tests to help ensure correct connections of differential relays and polarizing circuits of phase and ground relays. Although other preparatory tests are mentioned in this guide, these tests are not discussed in detail.