Measurements for effective potential increase in event of high-current earth fault

Abstract

In practice, there are open questions in NOSPE (low-resistance grounded) medium-voltage networks regarding the correct application and interpretation of (DIN) EN 500522 for the assessment of personal safety at grounding systems. For the first time in German-speaking countries, earth fault tests were designed and carried out in Uckermark, Brandenburg (Germany). The presentation of real current and voltage distributions provides information about the correct interpretation of the theoretical model approaches according to (DIN) EN 50522 as well as a discussion about the application of possible modified models for the ground impedance and the reduction factor. On the basis of the results, the question of how measurement variances occur with the so-called 4-probe measurement method was further investigated.