Abstract: A method for detecting a fault in an energy supply network. State values are determined for a plurality of measuring points. The state values, which specify an electrical state of the energy supply network at the respective measuring point, are transmitted to a control center. The state values are used by an evaluation device for detecting a fault in the energy supply network. In order to detect errors in energy supply networks with low short-circuit currents with high reliability and selectivity, the evaluation device performs a state estimation, using a model description of the supply network suitable for describing possible electrical states of the energy supply network on the basis of state variables. The estimation examines whether an electrical state at least approximately matches the respective state values, can be described by the model description. If such a state is lacking, the evaluation device generates an fault detection signal.

Abstract: A method for detecting a fault in an energy supply network. State values are determined for a plurality of measuring points. The state values, which specify an electrical state of the energy supply network at the respective measuring point, are transmitted to a control center. The state values are used by an evaluation device for detecting a fault in the energy supply network. In order to detect errors in energy supply networks with low short-circuit currents with high reliability and selectivity, the evaluation device performs a state estimation, using a model description of the supply network suitable for describing possible electrical states of the energy supply network on the basis of state variables. The estimation examines whether an electrical state at least approximately matches the respective state values, can be described by the model description. If such a state is lacking, the evaluation device generates an fault detection signal.

Abstract: A method detects a high-impedance fault occurring in an electric distribution circuit that distributes a three-phase alternating current. The method includes the steps of applying a plurality of electrical signal analysis techniques that provide a plurality of fault detection indicators, and generating a signal that indicates a high-impedance fault depending on the outcome of the fault detection indicators. The method is characterized by determining a randomness of the residual current of the three-phase alternating current prior to determining the plurality of fault detection indicators, and generating a trigger signal depending on the randomness of the residual current. The step of determining the plurality of fault detection indicators requires that the trigger signal has been generated.