Magnetic field generated by short circuit current in the 110 kV power system

摘要

Electric fields within tissues induced by magnetic fields including transients or short-term peaks should not be time averaged and be regarded as instantaneous values as established in the ICNIRP (International Commission on Non - Ionizing Radiation Protection) guidelines. Measurements of power lines magnetic fields with regard to human beings exposure are carried out typically with maximum current load at current balance condition when fields from lines compensate each other. In the fault conditions, like current unbalance due to short circuit, magnetic field increases thus in that case field should be estimated and compared with limits. It is not easy to measure transients caused by short circuits because of its random character, however it could be calculated. In this paper authors show magnetic field generated by short circuit current and compare it with ICNIRP limits. Type of short circuit, earthing system and also current distribution through the tower and earth are discussed. Maximum magnetic field in the worst case conditions is estimated.