Moisture Retaining Test of Bentonite, Gypsum, Vermicast, Coco Peat and Peat Moss Mixtures for Grounding System Purposes

Grounding systems play a crucial role in protecting an electrical power system in order to provide a safe path for fault current flow dispersion, especially in the event of lightning to avoid damage towards electrical equipment and malfunctions of such system. Therefore, an effective grounding system should possess low current resistance, allowing the fault currents to flow in the least resistance path as quick as possible. There are several methods to obtain an effective grounding system with low earth resistance value. The most common is by introducing enhancement materials, which either natural or chemical based. Note that only Natural Enhancement Materials were employed in this work which include Bentonite, Gypsum, Vermicast, Coco Peat and Peat Moss, which were chosen based on their moisture retaining capabilities. This is due to the reason that Natural Enhancement Materials will not alter the characteristics of the surrounding soil and proved to be environment friendly, as opposed to the Chemical Enhancement Materials. A total of 15 samples with various ratios including 4 Soil Reference samples, i.e. from previous Grounding Systems 2016/2017, 2017/2018, 2018/2019 and 2019/2020, were tested. Moisture Retaining Test were conducted twice a week starting from 11th March 2022 until 10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">th</sup> May 2022, for a duration of 60 days once Volume Density Test was performed towards the 100% individually mixtures on day-0. It was concluded that the four best performed NEM mixtures in descending order were found to be Bentonite and Gypsum Mix A (86.72%), 100% Bentonite (86.59%), Bentonite and Coco Peat Mix A (79.69%), and Bentonite and Peat Moss Mix A (79.51 %). Note that Bentonite ratio was more in Mix A compared to Mix B.