Effect of realistic system modelling on low-voltage capacitor transient overvoltages

Although the switching of capacitor banks produces transients, such operations are necessary and an integral part of a power system. The transient produced in this way can propagate through the distribution lines and be magnified in shunt compensated loads. Magnifications of these surges are studied, and it is found that, if there are two LC loops with the same natural frequencies, the transient overvoltage produced by the switching of the capacitor in the first loop is magnified in the second one. The magnification depends on capacitance and frequency ratios. The paper analyses the transient response of a two LC loop system and shows how overhead lines, system interaction, loads and other capacitor banks can affect this magnification. The proposed method is used to analyse the magnification of overvoltages in a real system, and results obtained with and without the consideration of these main item parameters are presented