Sensor assembly and method for sensing status condition of electrical equipment

A sensor assembly for sensing a status condition of a liquid-filled electrical equipment comprising: a light source; a hydrogen detection section optically coupled to the light source for receiving light therefrom and having a hydrogen sensitive layer that changes an optical response with respect to the received light depending on whether an amount of hydrogen at the hydrogen sensitive layer is above or below a threshold; and an output section optically coupled to the hydrogen detection section for receiving light having interacted with the hydrogen sensitive layer, the received light depending on the optical response of the hydrogen sensitive layer. The output section outputs an output signal as a low-hydrogen output signal when the optical response corresponds to an amount of hydrogen below the threshold, and as a high-hydrogen output signal, different from the low-hydrogen output signal, when the optical response corresponds to an amount of hydrogen above the threshold.