I recently attended a training session with Omicron in Germany, looking at their primary injection test set for earth electrode and line impedance testing. We looked at how to set up a current injection, potentially up to 100 A, down an Overhead line or Feeder cable to achieve good separation between the electrode under test and the auxiliary electrode.
Previously, test methods have relied on dedicated cables for the measurement, which has limited the available area to deploy the auxiliary electrode, owing to land usage constraints and roads. So, being able to use something in a built-up environment on electrically large HV systems avoiding road closures, etc. comes as a breath of fresh air to a lot of engineers facing this problem.
Additionally, legacy test methods have been limited to test currents in the order of tens, and sometimes low hundreds of milliamps which really limits the scope and potential accuracy of the test – due to in-ground noise or difficult geologies. All too often when limited to small currents, the results can give rise to more questions than answers – so it’s nice to know it is possible to build certainty in your electrode system measurement.
I was really impressed by the ability to inject significant currents into the electrode under test, and therefore to measure resistance with much more accuracy, and to include the complex components of the earth resistance (impedance). Additionally, the tester allows the direct measurement of prospective touch voltages, allowing for earth electrode verification in situations where it is not possible to deploy any measurement leads at all. No way leaves or permits to access other people’s land – Super convenient.
“…I was really impressed by the ability to inject significant currents…with much more accuracy
We are currently exploring a number of opportunities to use this test methodology with our clients both in the UK and abroad, and if this sounds like something that your site would benefit from, please get in touch using either live chat or the contact us page.