FISO’s proposition to support the work of utility businesses is the Nortech Transformer Winding Hot Spot Temperature Monitoring System. Using the proven fiber optic technology, the Nortech system allows for direct, real-time, and long-term monitoring of power transformers, thus providing smarter dynamic substation and power grid management.
The TPT-62 fiber-optic temperature probe family employs industry standard 62.5µm core OM1 fiber optic for highly improved optical, mechanical, and reliability properties over legacy 200 µm core (1st generation) fiber optic sensors.
The EasyDisk sensor tip assembly ensures IEC60076-2 (Annex E) compliant installation and enables quick insertion of the probes into the spacers within the windings of transformers.
The Nortech Fiber Optic Monitors
The fiber optic signal conditioners are designed for direct, accurate and real-time temperature monitoring to manage and maximize your transformer’s performance.
The Nortech temperature monitor family comes in three different classes: the EasyGrid is the most comprehensive model, the EasyGrid LT is a compact and very cost-effective model for low channel count monitoring applications, and the EasyGrid Base is and even more compact model designed for easy network integration.
EasyGrid Key Features:
EasyGrid LT Key Features:
EasyGrid Base Key Features:
EasyTest Key Features:
The measurement principle is based on white light absorption/transmission by a GaAs (gallium arsenide) semiconductor. The impacts of temperature variations on this semiconductor are well known and predictable. As the temperature of the semiconductor changes, the semiconductor’s transmission spectrum (i.e. the light that is not absorbed) also shifts. At any given temperature, there will be a wavelength at which the transmission essentially jumps from 0% to 100%. This jump is called the absorption shift, and the relationship between the specific wavelength where the absorption shift takes place and the temperature is predictable.
The sensor consists of a tiny GaAs semiconductor crystal that is bonded to one end of a well-polished fiber optic.
The white light launched from the monitor into the fiber optic travels through to the GaAs crystal, passing through it while being partially absorbed, and is then reflected to the monitor by a mirror located at the very tip of the sensor. The light reflected to the monitor is coupled into an optical spectrum analyzer, which then measures the optical power transmission versus the wavelength. The position of the absorption shift is determined by the monitor using a proprietary signal analysis algorithm and is then correlated to the temperature of the GaAs crystal.
Furthermore, since the semiconductor will not change over time, all sensors can be interchanged with no need for calibration or entry of factors when swapping sensors. For the same reason monitors never need recalibration after leaving the factory when used under normal operating conditions.