The voltage and e-field distribution for clean insulator is illustrated in Fig. 3 and 5, respectively. The voltage is distributed to gradually decrease from insulator pin to insulator cap. Meanwhile, the e-field strength is quite high inside the glass material followed by nearby area of insulator pin and finally around the insulator cap. The density of field lines also represents the intensity of the e-field inside and around the insulator.The voltage and e-field distribution for contaminated insulator is different from the aforementioned condition. The voltage distribution seems to be distributed evenly from insulator’s pin to cap along the insulator shed as illustrated in Fig. 4. Meanwhile, e-field distribution in Fig. 6 concentrated more within the glass located between the insulator’s cap and pin followed by the insulator shed.