Consistency in ground potential rise estimation utilizing fall of potential method data

Analyzing fall of potential (FOP) test data from a grounding system current injection test is the prevalent method used to determine ground potential rise (GPR). Achievable tolerance in analyzing near ideal FOP results using recognized and alternative methods were assessed previously, whereas this paper investigates distortions by buried metallic systems, such as leaky cables and pipelines, based on both simulated and field data. To work correctly with "real" data, pre-conditioning FOP data may be necessary; removing "outliers" due to real world "pathologies" in the earthing system. Applying several "cost" functions to the methods created by the combination of conditioning schemes and FOP response models produced a significant number of estimation methods. To determine the most consistent estimation methods a methodology was developed which assessed all identified methods by comparing the estimates produced with the simulation result. This allowed the most consistent and accurate GPR estimation methods to be identified.