Fast distance protection for energy supply networks

Abstract

The invention relates to a method for detecting a short circuit (16) on a line (10) of a multi-phase electrical energy supply network, in which current and voltage sampled values are recorded and a fault signal is generated if a fault evaluation performed by an electrical protection device (12a) indicates a short circuit (16) present on the line (10). In order to generate a fault signal even more quickly than before, in particular for clear faults, instantaneous reference voltage values are calculated from instantaneous current and voltage sampled values recorded before the occurrence of the short circuit (16), and instantaneous comparative voltage values are calculated from instantaneous current and voltage sampled values recorded before the occurrence of the short circuit (16) and instantaneous current and voltage sampled values recorded during the short circuit (16). Then a rectified reference voltage value is calculated from consecutive instantaneous reference voltage values, and a rectified comparative voltage value is calculated from consecutive instantaneous comparative voltage values. The fault signal is generated if the difference of the rectified comparative voltage value and the rectified reference voltage value exceeds a triggering threshold value. The invention further relates to a corresponding electrical protection device (12a).

Description

technical field [0001] The invention relates to a method for detecting a short circuit on a conductor of a polyphase power supply network with a grounded neutral point, in which current and voltage sampled values ​​at a measurement location at one end of the conductor to be monitored are recorded by an electrical protective device, And if a fault analysis of the current and voltage sampled values ​​by the electrical protection device reveals that there is a short circuit on the conductor, a first fault signal indicating a short circuit on the conductor is generated. The invention also relates to a correspondingly constructed electrical protective device. Background technique [0002] In a power supply network with a grounded center point, it must be possible to disconnect a faulty conductor particularly quickly in the event of a clear short circuit. Due to the high short-circuit power, short-circuits in such supply networks are particularly dangerous because they place high...

AI Technical Summary

Problems solved by technology

[0006] The two described methods have the disadvantage that, depending on the size of the measurement window used, a minimum number of sampled values ​​is required for the calculation of complex current and voltage values, so that a decision about the presence of a short circuit on a wire can only be made with a certain delay out

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