E-field computation in 765 kV substation using CSM with reference to occupational exposure

Abstract

With the increase in transmission voltage level, and the guidelines of the International Commission on Non-Ionising Radiation Protection (ICNIRP), the effects of non-ionising radiation on biological elements at high-voltage substations have gained significant importance. The electric field (E-field) distribution in an upcoming 765 kV substation in the Indian subcontinent is computed using the charge simulation method (CSM). CSM is used to model the 765 kV bays, transmission lines, buses, and ground wires in the substation. The three-dimensional (3D) E-field is calculated through the superimposition of E-fields obtained in two orthogonal planes using infinite-line charges. This proposed method of using infinite-line charges gives realistic results. The simplistic model using infinite-line charges greatly reduces the complexity of the CSM-based model (due to the reduced number of charges) apart from increasing the CSM-based model accuracies. This fact has been demonstrated by comparing these results with those of CSM-3D-model of a detailed bay model (including major equipment and associated support structures). The complex-charge-based CSM helps in computing the root mean square value of the E-field at a point, directly, as per ICNIRP guidelines. This RMS value of the E-field is compared with the occupational exposure reference value prescribed in the ICNIRP guidelines. The Institution of Engineering and Technology 2017.