Abstract

A significant majority of overhead transmission lines’ (OHLs) outages is due to backflashovers caused by direct lightning strikes: the realistic assessment of the lightning performance is thus an important task. The paper presents the analysis of the lightning performance of an existing 150 kV Italian OHL, namely, its backflashover rate (BFOR), carried out by means of an ATP-EMTP-based Monte Carlo procedure. Among other features, the procedure makes use of a simplified pi-circuit for line towers’ grounding system, allowing a very accurate reproduction of transient behaviours at a very low computational cost. Tower grounding design modifications, aimed at improving the OHL lightning performance, are also proposed and discussed.

Highlights

  • The lightning performance assessment of high voltage (HV) and extra high voltage (EHV)overhead lines (OHLs) is paramount, as the total outage rate of such lines is mostly influenced by the backflashover rate (BFOR) and the shielding failure flashover rate (SFFOR)

  • Overhead lines (OHLs) is paramount, as the total outage rate of such lines is mostly influenced by the backflashover rate (BFOR) and the shielding failure flashover rate (SFFOR)

  • Monte Carlo procedure for BFOR evaluation should employ an accurate model of tower grounding system, able to simulate the response of the system during fast transients related to lightning

Read more

Summary

Introduction

The lightning performance assessment of high voltage (HV) and extra high voltage (EHV). Drastically reduced computation times, allowing the use of a detailed ATP-EMTP [25] model as the simulation engine in a Monte Carlo procedure for line BFOR evaluation [26,27,28]. The line is studied by means of the ATP-EMTP Monte Carlo procedure described in [26,27]; grounding system arrangements used by Terna are simulated by means of the pi-circuit model presented in [24], for different soil resistivities, ρg , ranging from 10 up to.

Subtransmission Lines
Towers
Grounding System Arrangements
ATP-EMTP Monte Carlo Procedure for BFOR Calculation
Statistical Inputs of the Procedure
OHL Model
Line Insulation Model
Lightning Stroke Model
Grounding System Model
Pi-Circuit Synthesis Procedure
Pi-Circuit Parameters of Terna Grounding System Arrangement
Results
Adopt a Larger Grounding System
Add a Second Shield Wire
Add Four Vertical Rods at the Tower Base
Install Guy Wires and Ground Ring
Increase Insulator String Length
Conclusions
Full Text
Published version (Free)

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call