Advantages of Phasor and Vector Oriented Testing in Substation Grounding Safety

Current injection techniques used for testing grounding systems have evolved over the past two decades. They promoted the development of some test equipment that is capable of measuring the magnitudes and angles between injected current and split network currents, and between injected current and the network resulting voltages. Traditional test methods for ground grids found in standards such as IEEE 81-2012 need refreshing. These methods haven't changed in a long time and they follow a scalar based approach. Phasor-based methods for current injection help to assess the grounding systems and soils in a more natural state of operation. This paper compares scalar oriented testing vs phasor and vector oriented testing for analysis of substation ground grids. Benefits and disadvantages are listed for both approaches for the following tests: four pin (soil resistivity), three pin (ground grid resistance), fall of potential, current split, and touch and step voltage tests.