Aarding: Tower footing resistance

Do you want to be an expert on the topic of tower footing resistance measurements? This course addresses everything you need to know to perform a measurement of the tower footing impedance (or resistance) in an overhead line. The theory for low frequency and high frequency behaviour is treated in different sections. Some simple tools are provided to estimate values through calculations and perform an analysis of measurement results. At the end of the module your knowledge will be tested. What you should know is that only the questions in final chapter (“Test your knowledge”) are used for grading your final score. All other questions are for feedback and learning purpose only.

Important: in order to finish the course successfully, all modules shall be graded 70% or higher. Then, at the end of the course you will receive a certificate.

Module A12; Measurement of overhead line tower footing impedance

This course module provides detailed descriptions of the different methods to measure the tower footing resistance (in low frequency) and impedance (at higher frequencies). The advantages and disadvantages are explained and some examples are presented to get some experience.

Tools

Tools: two simple excel tools are made available; One tool supports the Fall of potential method and the other tool the Oblique probe method.

Prerequisites for the use of the tools: Microsoft Office Excel shall be installed with the option to run VBA macro’s. If the user wants to extend or change the tool experience with Excel is necessary.

Other

References: this module refers to the EPRI Guide for transmission line grounding (Grounding guide), Cigre technical brochure 781 and other documents.

Key words: Earthing; grounding; overhead line; tower; transmission; distribution; tower footing impedance; tower footing resistance; measurement; low frequency; high frequency; fall of potential method; oblique method; impulse method; soil resistivity

Trefwoorden: Aarding; bovengrondse hoogspanningslijn; mast; transmissie; distributie; mastvoetimpedantie; mastvoetweerstand; meting; laagfrequent; hoogfrequent; fall of potential methode; scheve methode; impulse injectie methode; bodemweerstand