Harmonic Interference From Distribution Systems

The paper presents the techniques and measures used by Calgary Power Ltd. to mitigate inductive interference problems into communiation circuits. Investigation of several cases of triple harmonic-noise problems indicated a new role of triple harmonies, generated by distribution transformers, in the interference mechanism. Trriple harmonic currents on distribution phases form an unbalanced set of phasors which have in general an equivalent positive, negative and zero-sequence components.