Sensor assembly and method for determining the hydrogen and moisture content of transformer oil

A sensor assembly for sensing a hydrogen and moisture content of insulation liquid of a liquid-filled electrical equipment, the sensor assembly comprising:

• at least one electromagnetic radiation source configured to emit electromagnetic radiation;
• a water detection section configured to receive a water-containing component of the insulation liquid when the sensor assembly is in operational connection with the electrical equipment, and to be illuminated by electromagnetic radiation from the at least one electromagnetic radiation source;
• a first electromagnetic radiation detector configured to detect electromagnetic radiation coming from the water detection section at a wavelength indicative of an amount of water present at the water detection section;
• a hydrogen detection section configured to receive a hydrogen-containing component of the insulation liquid when the sensor assembly is in operational connection with the electrical equipment, and to be illuminated by electromagnetic radiation from the at least one electromagnetic radiation source;
• and
• a second electromagnetic radiation detector configured to detect electromagnetic radiation coming from the hydrogen detection section at a wavelength indicative of an amount of hydrogen present at the hydrogen detection section.