Maßnahmen im aktiven Verteilernetz bei Verlust des Kurzschlussstroms

Sufficiently high short circuit currents are required for correct functionality of protection devices and for a safe and reliable operation of electrical distribution networks. Both in network and in islanded operation with distributed generation units in fault situations sufficiently high fault currents are necessary to maintain selectivity and speed of protection devices. In islanded operation in case of loss of external fed short circuit currents it can be possible, that a not sufficiently high fault current to initiate the protection device occurs. To solve this problem, an undervoltage controlled overcurrent protection in combination with an auxiliary current source is presented.