Triangulation and 3D location estimation of RFI and Partial Discharge sources within a 400kV substation

The 3D location of RFI (Radio Frequency Interference) and PD (Partial Discharge) sources within a 400 kV substation are presented in this paper. The technique involves the employment of four small broadband mobile antennas attached to a fast digitizing scope. The time differences of arrival within a group of four received digitized signals are used to triangulate the 3D position of radiating RF sources. Results presented demonstrate the capability of the technique. Two specific locations at heights of around 7 m and 9 m pinpointed regions associated with the surrounding joint areas of a recently refurbished bus bar. Deformed inner cable cores were discovered at one of these locations. After remedial attention, cleaning and reconnection of the bus bar the RFI problems disappeared. Other RFI source locations were pinpointed, and surprisingly, some of these were related to nearby lighting.