Determining of a power line fault

A device for determining a fault in a protected zone of a power line, the device being configured to:

• obtain voltage and current measurements at a measurement point at one end of the power line,
• process the measurements in a number of parallel processing branches comprising at least two parallel processing branches, wherein the processing in each branch comprises
• filtering the measurements in a corresponding low pass filter for obtaining a corresponding set of filtered measurements, wherein the cut-off frequencies of the low pass filters in these parallel processing branches differ from each other,
• performing reach calculations on the filtered measurements for obtaining corresponding reach point quantities, and
• comparing the reach point quantities with corresponding thresholds, and
• determine that there is a fault within the protected zone of the power line if any of the thresholds is crossed in any of the parallel processing branches.

A computer program product for determining a fault in a protected zone of a power line, said computer program product being provided on a data carrier comprising computer program code configured to cause a processor to, when said computer program code is being operated upon by the processor

• obtain voltage and current measurements of the power line at a measurement point at one end of the power line,
• process the measurements in a number of parallel processing branches comprising at least two processing branches, wherein the processing in each branch comprises
• filtering the measurements in a corresponding low pass filter for obtaining a corresponding set of filtered measurements, wherein the cut-off frequencies of the low pass filters in these parallel processing branches differ from each other,
• performing reach calculations on the filtered measurements for obtaining corresponding reach point quantities, and
• comparing the reach point quantities with corresponding thresholds, and
• determine that there is a fault within the protected zone of the power line if any of the thresholds is crossed in any of the parallel processing branches.