An evolution in cost effective power utility grounding asset management: Plan, design, build, assess & operate

Grounding systems are critical plant for the correct operation of major power installations, particularly major substations. As the average age of major substations in a utility's franchise increases, the likelihood that an assessment of the condition of a grounding system will be initiated. Whether or not the grounding system needs to be assessed in line with the substations age is often debated. However, the evidence is that the driving factors behind an assessment of a grounding system's aging or condition, is dependent on factors different to that of the remainder of the plant. Assessing the condition of a ground requires the execution of an appropriate regime of tests, conducted over the lifetime of the ground, and in some cases over the lifetime of the associated HV asset. Maximizing the knowledge gleaned from the information contained in these measurements is the art of the specialist, which distinguishes them from then infrequent practitioner. Experience over the past 20 years of managing grounding assets, has demonstrated that managing grounding systems, can and should evolve from a perfunctory duty to a recognized, significant contributor to the proper functioning of every power utility asset and to the network as a whole. Many existing grounding asset management strategies focus on design. This has and is resulting in a lack of rigour in condition monitoring and unidentified failures for ageing assets. Asset management must consider a cost effective method of life cycle integrity verification. This paper presents the benefits of such a method over existing strategies by explaining why excessive focus to a particular phase of the grounding asset life-cycle produces a false security in the management of an aging asset. The various life-cycle stages of a grounding asset need to be balanced against the rest of its expected lifetime, which can be evaluated by the effectiveness of each stage to maximizing an assets lifetime. The major insight to this effectiveness is the realization that the lifetime of these assets if primarily driven by external forces.