When nature dictates the terms
In the twenty-first century, the forces of nature continue to threaten the stability of cities and countries. In particular, lightning strikes cause substantial damage to overhead power lines by interrupting the power supply to hundreds and thousands of energy consumers. The lightning protection devices not always cope well with their functions. This once again was evident to Streamer International AG experts who visited energy facilities in Colombia.
Experts of EPM Columbia, Streamer's customer, demonstrated the power line equipped with surge arresters (SA). This conventional lightning protection device is widely used to protect power lines from lightning discharge impacts. Yet, with Colombia lines, these devices were not so effective: SAs installed on poles of power line had signs of damage. Many of them were out of use after direct lightning strokes.
This part of Latin America is exposed to the high thunderstorms activity. Moreover, the power line runs close to the city of Medellin, at an altitude of over 1400m above sea level, in extremely hilly terrain with high soil resistivity. The line, therefore, is subject to a large number of atmospheric overvoltages, and requires robust surge protection.
Surge arresters installed on pole mounted transformers, cable inputs, switchgear and other costly equipment in Colombia have a custom design that ensure quick replacement of a damaged unit with a new one. This also confirms the assumption that local linemen face this kind of issue quite often. In order to facilitate operational conditions of SAs, that protect sensitive equipment, and the equipment itself, Streamer have designed special line lightning protection devices (LLPDs), that can both dissipate overvoltages to the ground and interrupt the fault current at the same time.
Streamer LLPDs that have proven themselves to be very effective in regions of high thunderstorms activity, become more and more usual in Latin America. In particular, a 13,2 kV line was equipped with Streamer LLPDs in Colombia in December 2017. Within two months of operation, several one-time indicators have been triggered, three of them indicated operations of all LLPDs installed on one pole, that tells about a direct lightning stroke hit at this pole. No equipment failure or switchgear trips were observed on protected line after implementation of Streamer LLPDs. Which means that Streamer LLPDs had fulfilled their function and prevented detrimental consequences of direct lightning strokes hitting the line.