Interference between overhead lines, communication circuits and pipelines is caused by asymmetrical currents, which may be due to short-circuits, asymmetrical operation or asymmetrical design of equipment, especially asymmetrical outline of overhead line towers with respect to pipelines and communication circuits. This interference is based on inductive, ohmic and capacitive coupling between the short-circuit path (e.g., overhead line) and the circuit affected by interference (e.g., pipeline). Normal operating currents, respectively voltages, cause magnetic as well as electric fields which are asymmetrical in the vicinity of overhead lines which may cause interference problems in the long-time range.
Special problems related to short-circuit currents, Page 1 of 2
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