A Novel Transmission Tower Model for Playback Testing of Lightning Events on Time Domain Relays

The advent of new time-domain-based protective relays (TDRs), which provide a marked improvement in fault detection and location, has encouraged the scientific community to explore their performance during different faults and lightning events. The phenomenon of back-flashover, resulting from lightning strikes on transmission towers or shielding wires causing flashover or breakdown of phase conductor insulation, initiates the propagation of voltage and current traveling waves along the phase conductors which are detectable by TDRs. Distributed parameter equivalent circuits such as the Multistory Tower Model (MTM) and the Simple Distributed Line Model (SDLM) have been widely employed to model towers for electromagnetic transient studies of lightning events. However, such models face challenges in simulating large systems due to computational demands. This paper introduces a new transmission tower model using lumped R-L circuit elements instead of constant parameter (CP) lines, offering an alternative approach to lightning back-flashover analysis. Simulations using the Electromagnetic Transients Program compare the proposed model against the MTM and the SDLM in terms of the voltages developed at various locations along the tower during lightning surges. The absence of CP line models in the proposed approach eliminates the need for small simulation time step sizes, significantly reducing simulation time compared to distributed parameter methods. This streamlined model presents a practical alternative for lightning surge analysis, which addresses computational challenges associated with large power system models.