Online Monitoring System for Transformer Winding Temperature Measurement

Model: Z_Temp-OTF-9000

The Transformer Optical Fiber Temperature Measurement System shall include:

1. Fiber optic temperature controller (6~10 channels, etc.)

2. Waterproof terminal box

3. External optical fiber

4. Penetration panel

5. Rain cover for penetration panel

6. Tank wall flange ring (including O-ring gasket)

7. Penetrator

8. Internal optical fiber

9. Fiber optic probe

Product Introduction:

The Z_Temp-OTF-9000 Transformer Fluorescent Fiber Optic Online Monitoring System, or fiber optic thermometer, can directly, real-time, and accurately measure the temperature of transformer windings. With both RS-485 data output and analog output, the fiber optic thermometer is easily integrated with monitoring and data acquisition systems or other data logging systems. Based on field experience, the independently developed fiber optic sensor is more robust, and the ST standard connector makes it more convenient and flexible at the transformer tank interface. The sensor is made of special quartz fiber with a diameter of 300um, offering greater flexibility; it does not break even when bent to a radius of about 3cm.

Product Principle:

The transformer winding itself is a live component, making direct temperature measurement challenging due to insulation requirements, especially for higher voltage windings. Although fiber optic technology can achieve this, it is costly. Therefore, the commonly used winding thermometer actually provides a simulated value that reflects winding temperature by combining the top oil temperature and operating current, rather than measuring the actual winding temperature.

Methods for determining winding hotspot temperature can be divided into three types: direct measurement, thermal simulation measurement, and indirect calculation.

Direct measurement involves embedding sensors in the windings, with fiber optics transmitting signals to achieve online, real-time, and accurate measurement of winding hotspot temperature under high voltage and high magnetic field conditions. This is the preferred method for future transformer temperature rise tests in hotspot measurement. The fluorescent material sensor is directly attached to the end of the fiber optic probe. The probe is made of materials proven to be long-term compatible with oil-immersed high-voltage power transformers and offers excellent electrical performance. During temperature rise tests, only the fiber optic probe needs to be installed (using the factory's existing tools), and the data measured by the probe can directly indicate the actual temperature of the winding's hottest spot, with simple operation. The temperature sensor used is made of a stable, high-temperature-resistant fluorescent material, placed directly at one end of the optical fiber.

The principle is that when a light pulse from an LED source is sent through the optical fiber to the temperature sensor in contact with the winding, the pulse excites the fluorescent material in the sensor, causing it to emit fluorescence with a longer wavelength. The temperature of the sensor is measured based on the decay time of the returning fluorescence. After processing, the temperature value and relevant system parameters are displayed, and the temperature information is simultaneously transmitted to the control room. This system can provide accurate winding temperature when the transformer is under peak load or emergency overload conditions, allowing the transformer to adjust its load promptly based on the measured actual winding temperature.