PRACTICAL EARTH TESTING - OVERCOMING MEASUREMENT PROBLEMS ON SITE

摘要

Ensuring the integrity of an earthing system after design and installation or maintaining existing systems requires testing. This paper will discuss the practicalities of carrying out testing and offer some novel measurement techniques to overcome the problems encountered whilst making measurements on telecommunications earthing systems. Telecommunications earth systems may consist of a number of elements, earthing as lightning protection, earthing for radio frequency interference and earthing of the power system. It is not unusual for each of these elements to be bonded together at some point. A method of testing without the need for powering the system down will be described. Also, a method of testing earth electrodes whilst still connected to an operational system will be described and explained. This method can be used to individually test electrodes interconnected with other electrodes or other earthing systems. Prior to installing earth electrodes system the resistivity of the soil must be measured a simplified method avoiding calculation is explained. Usually earth electrode resistance is measured by installing temporary electrode, this can be impossible in urban and certain industrial locations. A 'stake-less' measurement technique overcomes this problem. Finally, some 'tips and tricks' will be discussed which can simplify on site measurements.