Fiber-Optic Technology Makes It Possible to Monitor a Transformer’s “Temperature”
I. “Fiber-Optic Sentinels” Inside Transformers: Installation Challenges Hide Technical Hurdles
Installing a “thermometer” in an operating transformer is by no means a simple technical task. The high- and low-voltage windings inside the transformer act like a dense “fortress of copper and iron.” The installation plan faces a tremendous challenge: fiber-optic sensors must be positioned precisely near the monitoring points without compromising the equipment’s insulation performance.
The immense pressure exerted by the copper windings keeps the insulating spacers firmly in place; attempting to forcibly remove them could damage the equipment. This detail precisely exposes the limitations of traditional monitoring solutions—in a high-voltage, sealed environment, the margin for error in any mechanical operation is extremely low.
The breakthrough came from a thorough disassembly of the equipment’s structure: the technical team discovered that the thickness of the insulating plate itself, combined with the surrounding gaps, formed a natural passageway. Through a customized mounting process, the optical fibers were directly embedded into the gaps and rigidly bonded to the insulating plate, thereby avoiding the pressure zone of the windings while ensuring sensing accuracy. The successful deployment of six sets of optical fiber sensors not only solved the installation challenge but also established a reusable standard for optical fiber implantation in high-voltage equipment.
II. Data Doesn’t Lie: The Technical Confidence Behind the 35°C Reference Value
The most closely watched aspect of the experiment was the real-time performance of the fiber-optic sensing system. Once the demodulator was activated, stable data output was recorded across all six channels:
l Channel 1 corresponds to high-voltage Phase A, with a reference temperature of 35.2°C
l Channel 2 corresponds to low-voltage Phase a, with a reference temperature of 34.8°C
l At the moment of load switching, the response delay to temperature fluctuations was < 0.5 seconds
This stability stems from the unique advantages of fiber-optic sensing: strong resistance to electromagnetic interference, maintaining accuracy even in the strong electromagnetic fields of transformers; distributed monitoring capabilities that enable centimeter-level localization, eliminating the monitoring blind spots of traditional point-type sensors; and Zero Degree Optoelectronics’ proprietary demodulation algorithm, which controls temperature measurement errors to within ±0.5°C.
Compared to traditional infrared temperature measurement or thermocouple monitoring, the breakthrough of the fiber-optic solution lies in its “fully online” capability—installation and data collection can be completed without interrupting equipment operation, which is crucial for ensuring the continuous operation of the power system.
III. The Story Behind Two Collaborations: The Urgent Need for Smart Power Systems
As core equipment in the power grid, the temperature rise of transformers directly affects power supply safety. Traditional monitoring methods either lack sufficient accuracy or are susceptible to environmental interference, making it difficult to meet the demands of complex operating conditions brought about by the integration of renewable energy sources.
The maturation of fiber-optic sensing technology, however, provides a systematic solution:
l For power companies, real-time access to temperature rise data enables early fault warning and reduces O&M costs by more than 30%
l For grid safety, distributed monitoring builds a health profile of equipment, providing data support for dispatch decisions
l For industry development, this “equipment condition visualization” technology is a key piece of the smart grid puzzle
The success of this experiment not only validates the technical solution but also marks a crucial step in the transition of fiber-optic sensing technology from the laboratory to engineering applications.
