The Electrical discharge (ED) phenomenon is very harmful for electrical appliances and its early detection could be a cost effective approach for the industry. Although many techniques are used for ED detection yet no technique has presented widely acceptable solution. Still the subject needs parallel study of the detection techniques. In this study, partial discharge signal has been captured by the three techniques using fiber optic sensor (FOS), Piezoelectric Sensor (PZT), leakage current (LC) techniques. In these experiments, FOS shows good sensitivity in the range of applied high voltage> 5 kV. The sensitivity and noise level of ED signal was different in these two experiments. The location of a ED was demonstrated in a 500 gallon water tank using convolution method.