Earth protection system, also known as grounding system, is to protect the equipment in the substation by providing low impedance path for the fault current to flow to the earth. Besides, this system plays a significant role in safety assurance of the personnel working within or nearby the substations. In order to meet the power system performance and electrical safety, the earth resistance needs to be low enough for the required level of fault current to flow. Also, dangerous potential gradient of fault current should not arise to any metal or conducting equipment from the ground. As Singapore has underground power transmission and distribution system, earth protection is vitally important. The objective of this paper is to analyze the schemes of earth protection system with its different parameters, and associated effects in the AC electrical substations in Singapore geographical areas. Earth conductor sizing, scheme resistance, the criteria and permissible imposed touch and step voltage levels need to be calculated, to analyze the scheme of earth protection system. Case study examples substantiate the design schemes to achieve the safety level.