GA-CSM based optimized clearances for the reduction of occupational exposure in EHV substation

Abstract

• Multi-objective GA-CSM based algorithm is proposed, for the first time, to identify the optimal ground clearances of EHV substation conductors for adherence to the ICNIRP guidelines. • CSM models are developed as per the actual layout of the substation and E-fields are computed in view of occupational exposure. • Modified ground clearances are obtained for the existing conductor arrangement and for the best topology among the transposed topologies. • Novel substation layout with reduced inner bay heights is proposed. The magnitude of the electric field (E-field) in a 765 kV substation is reduced by altering the conductor clearances in view of the occupational exposure limits. Multi-objective genetic algorithm (GA) along with the charge simulation method (CSM) is utilized in arriving at the optimal clearances of the substation conductors. An EHV substation is modeled with the dimensions and the clearances as in the actual layout of a substation. The E-field results obtained using the finite-line based modeling and infinite-line based modeling of conductors, are compared in terms of the model accuracy and the computational time. The advantages of using the infinite-line based CSM model in view of the occupational exposure is detailed. With the proposed GA-CSM routine, the maximum value of the E-field in the substation is reduced to 10 kV/m (from the existing value of 13 kV/m). The proposed method is used with the existing topology and the best possible transposed topology to obtain the modified layouts. A novel EHV substation layout with different ground clearances for the inner bays and the outer bays is presented. The GA-CSM routine proposed in this work is applicable to any EHV substation with the multiple conductor arrangements.