Cluster Analysis of Geomagnetic Disturbances Impact on Reliability of Microprocessor Protection

In the secondary circuits of power system facilities geomagnetic variations cause geoinduced current which is, according to the nature of its influence, a conducted electromagnetic disturbance; so, it can result in the incorrect operation of microprocessor protection relays. The geoinduced current values are determined by the intensity and duration of variations of the geomagnetic power and angle components. The fuzzy cluster analysis was carried out to define the influence of geomagnetic variations on the operation of microprocessor protection relays maintained in the power system facilities of the Republic of Khakassia. The authors also define time and amplitude intervals of the variation rate for geomagnetic power and angle components, which cause incorrect operation of microprocessor protection relays. The results of the fuzzy clustering show proper coincidence with the results obtained with numerical differentiation of functions in a tabular form, with the construction of Lagrange interpolation polynomials of the second order. The analysis outcomes are important for the prediction and prevention of possible incorrect operation of microprocessor protection relays at the power system facilities during geomagnetic storms.