ABSTRACT
The best method to provide shielding to the bus and equipment is to locate the shield wires or masts so that they enclose the objects to be protected. The basis of design for substation shielding is somewhat different from that for lines. This chapter shows that the differences and similarities to the shielding of lines. Although the shielding diagrams are simple and interesting to draw, for most problems it is unnecessary to construct them. As portrayed by the shielding diagrams, shield wires provide superior protection. However, there exists a concern among some utilities that breakage of the shield wires may occur resulting in faults within the station. In 1942, C. F. Wagner et al. published a paper titled “Shielding of Substations” in which they presented results from laboratory tests. The tests performed attempted to model the downward leader from the cloud by using a rod placed vertically above a model shield wire or mast.
