Determination of Impulse Polarity Effect of Earthing Systems by Field Measurement

Abstract

Within the past couple of decades, a lot of emphasis have been made by researchers in the field of electrical power and high voltage engineering in particular towards the design, installation and analysis of earthing systems suitable for lightning protection, and other unwanted electrical interference. Although all these have healed significant improvement in design and installation, it has been fairly understood by many researchers and engineers engaged in the design and installation processes of earthing systems. On the other hand, their analysis at times can be very complex ranging through the use of rigorous computer aided simulations to field test. Some researchers even hold the opinion that, field test are time consuming, expensive and not properly understood. Adding to this, design engineers are also faced with numerous soil profiles and weather conditions around the world making it difficult to draw a definite conclusion on standard design considerations that could be applicable uniformly on different soil conditions. Adding to these complexities, effect of the performance of an earthing system in practice does depend solely on the design or conductors buried, soil conditions and analysis but as seen in this study, the effect of impulse polarity also plays a significant role to the earthing system’s performance. In this study, it is observed that positive and negative impulses also present a challenging outcome to the earthing systems performance. It is also concluded in this study that; the impulse resistance varies with the type/design of earthing system installed.