High frequency behavior of soil improver compounds

The method of using soil improver compounds in order to improve the DC resistance of an earth electrode is becoming more and more known all over the world. In the past years many practical but not effective methods were used as soil improver compounds. There are still some references that one can find, which identify some compounds like salt and coal as soil improver compounds, however they may cause accelerated aging of the earth electrodes as well as environment degradation and this is completely unacceptable. In order to avoid the uncontrolled use of non acceptable improvers recently a new European Standard was issued under the series of EN 50164 (part 7) specifying testing and performance requirements of soil improver compounds. Although there are many references on the performance of soil improvers showing their effect on the DC resistance of an earth electrode, there is not much information about their behaviour under high frequencies. This paper aims to investigate the performance of various earth electrodes installed in the field with and without various soil improver compounds under high frequencies.