Abstract: A method of monitoring a parameter of an electrical network includes using sensors to measure a value of a parameter of the electrical network during each sampling period within a selected time section. During each iteration of a plurality of iterations of a sliding window algorithm, wherein within each of the iterations a starting time of a sliding window of the sliding window algorithm within the selected time section is incremented by a selected increment, an average of the measured parameter values over the duration of the sliding window for each of the starting times is calculated. The duration of the sliding window in each iteration is different from the duration of sliding windows in other iterations. A representative value of the calculated averages of the parameter is calculated for each iteration. An alert is issued if indicated by the representative value.