BAU+ Sensor

The BAU+ (Bushing Adapter Unit) sensor is a multi-purpose sensor that eliminates the need for a separate sensor for each application, providing bushing insulation signals, partial discharge detection in bushings and transformers, and noise-filtering circuitry via Rogowski coils. It carries an IP-67 environmental rating and is designed for use in power transformers, isophase bus ducts, and HVCTs.

The BAU+ sensor is built in three separable sections: body, adapter, and cable connector. The body can be detached from the adapter by removing just three screws. This gives technicians direct access to the bushing’s test tap, or the adapter can be removed entirely for additional working room, without needing to replace the whole sensor assembly.

The BAU+ sensor uses three layers of protection: six voltage limiters with a current-balance circuit for open circuit protection (the lowest in the industry), two surge protection circuits for switching and system transients, and a fail-safe circuit that automatically grounds the tap if the first two protections fail.

1. Open Circuit / Voltage Limiter – Six voltage limiters provide open circuit protection. A current balance circuit is used to distribute the stress equally between limiters. Dynamic Ratings offers the lowest open circuit protection in the industry.
2. Surge Protection – Surge protection provides safety for equipment and personnel. Two surge protection circuits provide protection for switching and system transients.
3. Fail Safe Circuit – A fail safe circuit automatically grounds the tap inside the body of the sensor should the open circuit and / or surge protection fail.

Each BAU+ sensor delivers signals for imbalance, bushing leakage current, capacitance, power-factor, and partial discharge measurements — covering the core diagnostics needed to assess bushing insulation health in a single sensor.

The BAU+ sensor supports 50+ custom adapters to fit various test tap styles, and uses 50 Ohm coax cables for accurate signal transmission over longer distances, plus a Rogowski coil amplifier and cable to aid in partial discharge noise filtering.