Damaging long-term overvoltages on industrial capacitor banks due to transformer energization inrush currents

The issues concerning industrial power systems with large capacitor banks and energization of large furnace power transformers are discussed. The application of the capacitor banks could tune the system to a frequency that is excited by the furnace transformer energization current. Examples of situations in industrial systems are shown with field test data. Transient and harmonic simulations describing the phenomena are also shown. The effects on the capacitors caused by the overvoltages that are created due to the resonant conditions are discussed. The authors also address relevant capacitor standards and how they are related to this type of system phenomena