How Does A Deterioration In The Insulation Performance Of A Frequency Converter Cause A Phase-to-phase Short Circuit?

solid state frequency converter During long-term operation, the winding insulation system is subjected to various electrical stresses from high-frequency switching pulses, voltage pulsations, and partial discharges. These factors gradually damage the withstand voltage and dielectric properties of the insulation material. The degradation of the insulation dielectric properties leads to uneven electric field distribution between windings or phases, making areas with enhanced local electric fields more prone to breakdown. As the accumulated electrical stress on the insulation material increases, tiny conductive channels form within the insulation layer, potentially leading to conductive paths between different phases of the winding.

The cables and motor windings at the frequency converter 50hz to 60hz 3 phase output terminals also have requirements for insulation health. When the insulation of these connection parts ages, the interphase dielectric thins or cracks, weakening the insulation barrier that originally separated different phases. Traditional power system insulation design is based on power frequency conditions, while the 240v 50hz to 120v 60hz converter system includes fast switching action and higher dv/dt, which causes the insulation material to suffer nonlinear electrical stress.

Once the insulation layer can no longer maintain its original dielectric strength, the voltage difference between different phase windings makes it easier for current to cross the insulation interface, forming a large current path. In the single phase frequency converter system, this phenomenon manifests as a phase-to-phase short-circuit fault, with a rapid increase in current within a short period of time. Without proper protection, this could damage power devices or cause the system to shut down.