Electromagnetic compatibility in open air substations

An investigation was conducted into the electromagnetic compatibility (EMC) behaviour of the TRI transient measurement truck during shunt capacitor bank field tests at the Impala Substation. The measurement configuration during the measurements, the various measurement transducers and measurement cables used are analysed for their possible influence on the measurement results. Interference coupling mechanisms are discussed and different measurement methods, reducing or eliminating interference in the measurement results, are discussed. The measurement results of the shunt capacitor bank close, trip, and disconnector switching operations are examined for signs of electromagnetic interference (EMI). Specific measurements to investigate the influence of common mode currents, flowing on coaxial cable shields, on the measurement results were carried out and analysed. Several effects were observed which result from interference with the measurements and recommendations are made to prevent this occurring in future measurements. Suggestions are made for future measurements which would answer questions raised about the EMC behaviour of the measurement truck.