Estimating BFOR on HV Transmission Lines Using EMTP and Curve of Limiting Parameters

Abstract

This paper presents a method for estimating the backflashover rate (BFOR) on high voltage (HV) transmission lines. The proposed method employs a state-of-the-art model of HV transmission line (TL) for backflashover analysis, assembled within the EMTP-ATP program―with EMTP running in batch mode―to construct the curve of limiting parameters (CLP). The probability of backflashover occurrence at a particular TL tower is obtained by computing the volume under the surface of the probability density function of the bivariate log-normal statistical distribution (of lightning current parameters), bounded by the CLP in the coordinate system of lightning-current amplitude and wave-front duration. This probability, in combination with the estimated number of direct lightning strikes to TL towers, obtained from the application of the electrogeometric model, provides the associated BFOR, assuming it is further normalized on the basis of 100 km-years. The usage of the proposed method is demonstrated on a typical HV transmission line. A sensitivity study for estimating the BFOR with the proposed method is provided as well.

Petar Sarajčev

Full Professor | Department of Power Grids and Substations

Josip Vasilj

Associate Professor | Department of Power Grids and Substations

Researcher and Associate Professor at the Faculty of Electrical Engineering, Mechanical Engineering, and Naval Architecture in Split, where he teaches courses related to engineering economics, power system analysis, power grids and machine learning. His research focus is the application of advanced numerical methods to problems in the analysis and planning of power system operations.