The reliability of equipment has become a matter of the highest priority, and many control systems have been designed to protect and perform real-time diagnosis of all equipment. The main control parameters in any HPP are the voltage and the electric current. The latter can rise to unlimited levels due to short circuits or excess load, and the former produces surges or transients due to switching or atmospheric discharges. The third parameter of importance is the temperature, which is normally a consequence of the current. Any rise of temperature above 100°C may accelerate the aging process of the insulating material and conductors, or even destroy them, causing large financial losses for the company. A HPP may have hundreds of temperature sensors with all measuring points monitored from a control room.
In order to facilitate maintenance by decreasing the amount of copper wires, allowing remote sensing, and decreasing installation and operation costs, a fiber optic multiplexed temperature sensor was designed for use with large air-cooled generators. A system was designed that could be extended to address all of the temperature needs of a HPP, replacing the conventional resistive temperature detector (RTD) network.
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