Dangerous Resonant Phenomena in Power Supply Systems on the Second Harmonic Frequency Become Real

The article investigates the conditions under which in power supply systems with a nonlinear load and filter-compensating devices designed to filter higher harmonics and compensate for the reactive power of the load, they can create the possibility of developing dangerous resonant phenomena at a frequency of 100 Hz (second harmonic). Analytical estimations of the lowest values of the resonant frequencies, inherent in such systems, which depends on short circuit power in the node of filter installation, on the tuning frequencies of filter branches and their capacitive reactive power at the fundamental frequency, are performed. It is shown that the possibility of approaching the lowest resonant frequency to 100 Hz sharply increases in the presence of a third harmonic filter.