Optical Sensors for Power Industry Applications

Many sensing applications exist in the electrical power industry, particularly measuring electrically-related parameters such as voltage, current, electric and magnetic field strength, physical parameters, including temperature, pressure and applied force, and chemical monitoring.

Optical fibre techniques are well suited to many of these applications, and to the extreme environments often encountered in the power industry, because they are compact, lightweight, capable of distributed sensing, and, in particular, they are immune to electrical interference and have complete electrical isolation from the system being measured.

Despite the growing demand for accurate sensors in the electrical power industry, fibre optic (F/O) sensors have not penetrated the market in line with their potential.

This report details a programme of work carried out to explore the general field of F/O sensoring systems, and to investigate the specific opportunities available for the technology within the electrical power sector.

Following an introduction to F/O sensors and the power industry's requirements, there is a technical review of optical inter-actions pertinent to the operation of F/O sensors. The basic principles of F/O sensors are studied together with some alternative configurations, including intensity, wavelength and frequency modulation, and interferometric sensors and multiplexed sensing techniques.

The relative merits of the various configurations are highlighted.

A final section concentrates on sensing techniques and applications within the power sector, including current and magnetic field sensors, temperature measurement, voltage and electric field sensors and F/O sensors in circuit breakers.

Extrinsic sensors which incorporate materials exhibiting effects such as Faraday, electro-optic, piezo-electric, magnetostrictive absorption and fluorescence are considered together with intrinsic F/O sensors, including distributed sensors which utilize the sensing properties of the fibre itself.

Conclusions are drawn on the potential of F/O technology, key advantages and disadvantages are listed, together with the most important power industry applications.

Recommendations are made on the best way forward for companies interested in introducing optical and other sensing systems.