Three-phase AC filter capacitors filled with nitrogen gas provide long service life

TDK Corporation has announced the EPCOS B32377G, a new series of three-phase AC filter capacitors in delta connection filled with non-flammable nitrogen gas instead of the soft polyurethane resin employed in the existing series. In line with the megatrend of the electrification of mobility and renewable energies, these capacitors suppress harmonic distortions and lower reactive power at the input and/or the output of inverters. As a result, they enhance the power quality and can make applications more reliable, such as wind and solar energy and industrial drives.

These components, with a diameter of 75mm to 136mm and heights between 218mm to 351mm, range from 3 x 15µF to 3 x 330µF with rated RMS voltages of 330V to 1000V. As for lifetime expectancy at rated voltage, the series can operate for 250,000 hours at +70C at the hotspot, compared to the typical 100,000 hours of oil-filled components – and has a maximum hotspot temperature of +90C compared to the hotspot temperature of +85C for the oil-filled technology.

The winding construction is based on a metallised polypropylene film with self-healing properties. It shows low losses (tan ẟ) of 0.7 to 1.2 ∙ 10-3 and a high pulse-current withstand capability of up to 27.3kA. Their maximal RMS current can be 82A at +55C.

The components are provided with overpressure disconnectors for all three phases to ensure controlled disconnection in case of overload. Cage clamps with M4, M5, or M6 are used as terminals.

The main applications for the devices include input and output filters in inverter systems, and filtering of harmonic distortion in power inverters.