Low power high-speed folding ADC based partial discharge sensor for wireless fault detection in substations

Partial discharge is a well-established metric for condition monitoring and assessment of high-voltage plant equipment, such as switchgear, transformers and transmission lines. Traditional techniques for the detection of partial discharge pulses involve physical connection of sensors to the device under observation, requiring separate sensors for each item of plant, which can be costly and time consuming. Wireless partial discharge measurement provides an attractive alternative, since sensors can monitor multiple items of plant simultaneously. However, direct sampling of the received UHF partial discharge pulse is unsuitable for a scalable wireless sensor network, due to the high cost and power consumption required for high-speed data conversion. A sensor is proposed that utilizes a pipelined, sample-and-hold based, folding analogue to digital converter structure that features low power consumption when no signal is present, making it suitable for low-power data conversion of radiometric partial discharge. A proof of concept circuit has been developed using discrete components to evaluate the performance of the system with 8-bit resolution at 25 MSa/s and 56 mW of power consumption.