Adaptive mains filter

摘要

The device has a measuring device (34) for determining fault current (28) flowing through an adaptive mains filter, and an adjusting device (40) for changing cut-off frequency of the filter such that the fault current is attenuated below a predetermined level when the measuring device detects the fault current. The adjusting device has a switch for interrupting the fault current through the filter when the measuring device detects the fault current. The measuring device detects unbalanced electrical energy output from an electrical energy source (6). Independent claims are also included for the following: (1) a network for electrical energy supply of an electrical consumer from an electrical energy source (2) a method for protecting a filter.