Performance study of Full-Fiber optic sensor for simultaneous measurement of temperature and strong DC electric field

Stable operation of high-voltage direct current (HVDC) transmission systems relies on accurate monitoring of the strong direct current (DC) electric fields generated. This study presents an all-fiber sensor based on a single-mode-multi-mode-single-mode (SMS) reflective Michelson interferometer for this purpose. Finite element method simulations confirmed the bending of the optical fiber structure under the influence of the DC electric field, resulting in a measurable shift in the interference spectrum, a finding further validated experimentally by simulating the bending-induced light intensity distribution. The sensor demonstrates a measurable field strength up to 1000 V/mm and achieves a temperature monitoring linearity of 0.986. These characteristics make the proposed sensor a viable candidate for fault diagnosis and improved safety in HVDC transmission systems.