FOP - FSM Measurement - Relative position of the test conductors

Experimental evaluation of the measurement results based on FSM (Frequency Shift Method) concept in the non-conventional FOP (Fall-of-Potential) measuring scheme, for different angles between the test conductors, is presented in this paper. As it is well known, the optimal angle between the test conductors is θ = 90°. However, in practice, most often because of the physical obstacles in the surround substation, this condition cannot be provided. We have experimentally determined that the angle between the test conductors must be less than 60° relative to the optimal angle θ. In that case the corresponding measurement error is less than 3%.