Experimental study on current distribution characteristics of IGCT devices with temperature variation under mechanical DC circuit breaker operating conditions

• Novel segmented Rogowski coils enable non-invasive monitoring of IGCT current distribution. • IGCT current shifts towards outer device regions as temperature increases (tested up to 65°C). • 34kA tests reveal IGCT current redistribution also occurs with decreasing current magnitude. Integrated gate-commutated thyristor (IGCT) is an improved, commutated thyristor that could be turned off, offering significant advantages in terms of current capacity and on-state voltage drop. It is widely used in applications such as high voltage direct current circuit breakers, demonstrating promising prospects. However, temperature variations can affect the current distribution in IGCT devices, especially due to factors like parasitic parameters, which can lead to uneven current distribution. This uneven distribution may result in localized current concentration, potentially damaging the device and compromising system stability. To further investigate the current distribution characteristics of IGCT devices under circuit breaker operating conditions and to provide a feasible solution for current distribution monitoring, this paper proposes a non-invasive current distribution monitoring method based on segmented Rogowski coils. The method utilizes two high-precision segmented Rogowski coils to decouple from the device's busbar current, effectively sensing the current distribution state of the IGCT device. The paper also presents an equivalent experimental platform for an IGCT circuit breaker with a 34 kA current rating, and conducts experimental studies on the current distribution variations of press-pack IGCT devices under different temperature conditions (25°C, 45°C, and 65°C). The study explores the effects of device temperature and current magnitude on the current distribution. Furthermore, the proposed method provides an effective solution for non-invasive monitoring of the IGCT device's current distribution state.