Abstract
The paper analyzes the conditions for the functioning of basic numerical protection earth fault in medium voltage networks with earthed neutral Petersen coil. Analysis refers to the number of cell terminals and not to the protection at level of medium voltage substation. Selectivity conditions are presented. It is shown how a ABB numerical protection can be set to run selective. All analyzes are based on a concrete example, using a network of 20 kV with cable lines.
Cuvinte cheie
earth fault protection
Petersen coil
numerical protection