Safe Substation Grounding - Part II

Once the safe voltage limits for step and touch are determined, the design of a grounding system can be initiated. The criteria for determining these limits were already defined in Part I. This paper sets forth the fundamental aspects of a grounding design which are common to all substations and shows the differences between conventional and gas-insulated equipment installations. Other topics include: Characteristics of a combined grid - rod system, a general formula and tables for sizing of conductors and joints and methods for calculation of a ground resistance. Potentials of GIS enclosures during fault conditions, properties of concrete-encased electrodes and the use of bentonite are also discussed. The presented material of Part II is a preiminary version of updated information, proposed to replace Sections 7 - 12 of IEEE Std. 80/1976. Paragraphs 6.3 and 6.4 complement Section 6 of Part I, presented in the first report (Paper 80 SM 652-8).