Patent ID: 8335656

Claim:
A method for identification of a short circuit in an electrical power supply system including an associated tripping unit, sensor, evaluation unit and circuit breaker, the method comprising: determining, by the sensor, a current and a first and second time derivative of the current, continuously and successively at the same time and at the same time interval; processing, by the evaluation unit, each of the determined current and a first and second time derivative of the current as a digital numerical sequence; allocating, by the evaluation unit, each of the numerical sequences a limit value; comparing, by the evaluation unit, each of the numbers in the three numerical sequences with a respectively allocated limit value; allocating, by the evaluation unit, each number, which exceeds its allocated limit value based upon the comparison, a weighting number; adding, by the evaluation unit, the weighting numbers which belong to the same time to form a first weighting sum; adding, by the evaluation unit, up the first weighting sums for a number of immediately successive times to form a second weighting sum; comparing, by the evaluation unit, the second weighting sum with a further limit value; and considering, by the evaluation unit, a short circuit to have been identified if the second weighting sum exceeds the further limit value.