Protecting grounding bus mainly plays a protective role. Generally, it connects with grounding wire. Protecting grounding device is grounding pole made near the distribution room. Moreover, there are strict requirements for grounding resistance (grounding shaker is usually used for telemetry, grounding resistance should not be greater than 0.4 Euro), and neutral line is drawn from the neutral point of transformer. Although the transformer has been repeatedly grounded, but through the transmission line, the resistance has been relatively large, in addition, the neutral line also has the risk of breaking. Therefore, in the case of shell protection, it is not appropriate to use neutral protection, but to use grounding protection, and to distinguish between yellow and green conductors. The protective grounding wire should be used to protect the grounding electrode when it comes out to the site.