Analysis of surge protection performance in low-voltage AC systems with capacitive load

The performances of one-stage and two-stage surge protection schemes for the case of capacitive load are analyzed and discussed in the paper. Simulation software ATP/EMTP and MATLAB have been used for simulation of surge testing of considered systems with different cable lengths between protection stages and equipment under test, as well as with different values of capacitive load, which can be found in real low-voltage AC power circuits. Combination Wave and Ring Wave, which IEEE Std. C62.41.2 defines as standard surge testing waveforms, have been used as representative stresses. Performed analysis should point on influences and characteristics of different loads and length of connecting cables, which provide proper surge protection. Obtained results and their analyses could be used for determination of patterns for protection zones, which are useful for techno-economical optimization of surge protection. In the cases when proper surge protection cannot be achieved, possible solutions are proposed, discussed and analyzed.