Analysis of the reliability and applicability of grounding mode and the features of lighting location including roads in the hydropower station area,traffic tunnels,living quarters,outdoor switching station and outgoing line platform,the grounding mode of relay protection for the distribution system of outdoor area lightingin hydropower station were proposed.

To the common problems of protective earthing of underground electric equipments the author put forward some measures.

Preliminary discussion on protective grounding of power system in coal center laboratory;

Design and testing of the protective grounding circuit on woodworking machines

The paper has introduced the concept of grouding and neutral,analyzed the type and purpose of them,meanwhile pointed out the requirement of the protective connect to neutral and protective grounding,which is possessed of practicality and operabilit

Meanwhile,three important protections(over-current protection,leak-power protection,earthing protection) as well as the other protections under the well are described in detail,which embody that these protections are significant to secure production and products of coal mine.

The advantages and shortcomings of such common protections as zeroing protection, earthing protection and residual current protection are analyzed.

Effect of interconnection of protective earthing networks on high-voltage and low-voltage distribution systems;

Preliminary discussion on protective earthing of underground electric equipment in gold mines

This paper analyses the principle and functions of protective earthing and hanging earthing conductor,and analyses the existing problems in practice.