Fluorescent Fiber Optic Temperature Measurement – Application Background

 

 

 

1. The critical need for temperature monitoring of switchgear: During long-term operation of equipment such as switchgear and ring main units, the confined space and impaired ventilation/heat dissipation lead to overheating at critical points—including cable joints and circuit breaker contacts—due to poor contact or overload. Failure to address these issues promptly may result in accidents.

 

 

2. The essential requirement for monitoring hot spots in transformer windings.

 

The temperature of transformer winding hot spots is a critical parameter determining the transformer's load capacity and insulation lifespan. Traditional indirect measurement methods (calculated based on load current) exhibit significant errors and fail to accurately reflect the actual temperature at hot spot locations.

Fluorescent optical fibers provide precise winding temperature readings, enabling transformers to adjust their loads promptly based on actual temperatures;

 

 

3. Fire Prevention for High-Voltage Electrical Equipment

 

Malfunctions and fires caused by insulation aging or poor contact in high-voltage switchgear, cable joints, transformers, and similar equipment can be prevented through early temperature warnings.

The fluorescence optical fiber temperature measurement device is designed for early prediction of faults and fires caused by insulation aging or poor contact in the aforementioned equipment. The sensor probe can be directly installed on the measurement point via contact, thereby preventing electrical fires.

 

 

 

Principle of Fluorescent Fiber Temperature Measurement

 

 

Temperature measurement is based on the temperature-dependent fluorescence lifetime of fluorescent materials, employing the principle of inversely determining temperature from fluorescence decay time. This method constitutes a high-precision and highly reliable temperature measurement device. With core advantages such as electromagnetic interference resistance, tolerance to extreme environments, and measurement accuracy, it finds extensive applications in industrial production, power systems, aerospace, medical equipment, and other scenarios requiring stringent temperature measurement conditions.

 

The fluorescence optical fiber temperature measurement device primarily consists of a fluorescent material sensing probe, transmission optical fiber, a photoelectric module, and a signal processing unit.

 

The fluorescent material sensing probe, serving as the core temperature-sensing component, comes into direct contact with the target object. Its primary function is to receive excitation light and generate a temperature-dependent fluorescence signal.

 

The photovoltaic module is designed to generate pulsed excitation light, triggering the luminescence of the fluorescent material.

 

The optical transmission fiber enables bidirectional transmission of excitation light and fluorescence signals, serving as the critical component for enabling long-distance, interference-resistant temperature measurement.

 

The signal processing unit is primarily responsible for receiving fluorescence signals, calculating lifetime, converting temperature values, and outputting temperature data.

 

 

Product composition

 

 

 

The product consists of a fluorescent temperature-sensitive optical fiber + sensor probe, an extended fiber (8 m), a multi-channel receiver (with 3/6/9/12 channels optional), a display screen/intelligent control unit, and installation accessories. The optical fiber supports intermediate splicing, allowing flexible adaptation to varying wiring distances at different measurement points within the switchgear cabinet.

 

 

 

Installation Instructions

 

The installation precautions for fluorescent temperature measurement of busbars, circuit breaker contacts, and cable joints are as follows:

 

1. The temperature measurement point should be selected at a position with a relatively high temperature or close to high temperatures, and it should also be convenient for the fixation operation of optical fibers.

 

2. The temperature measurement point is 1 to 2 centimeters away from the head of the optical fiber sensor, and it is fixed with Teflon tape here. When fixing, do not apply excessive force to avoid damaging the fluorescent material inside the sensor.

 

3. During the process of arranging the optical fiber temperature probe and wiring, do not pull, entangle or step on it forcefully.

 

4. When installing the optical fiber connector bracket, the safety distance requirements for the installation of equipment inside the cabinet must be met. It is recommended that the distance for a 10kV voltage level be no less than 20 centimeters and for a 35kV voltage level be no less than 30 centimeters.

 

5. The distance between the contact point of the optical fiber sensor and the cabinet and the live parts should be greater than 30 centimeters.

 

6. The bending radius of optical fibers and their extensions should not be less than 5 centimeters.

 

7. At all times, it is necessary to keep the optical fiber ST interface and the optical end face of the optical fiber connector clean. When disassembling and assembling the optical fiber probe, promptly use the matching dust cap to protect the optical fiber ST interface and the optical fiber end face of the connection head to prevent contamination and scratches by foreign objects and dust, which could damage the optical fiber end face.

 

8. Unused optical fibers cannot be cut; they can only be wound up and stored properly.

 

 

 

Acrel System Configuration Solution

 

 

 

 

Project Overview: The power distribution system of Jilin High-Tech Fiber Co., Ltd. comprises a 10 kV substation and a 0.4 kV distribution room. This project involves over 90 high-voltage cabinets and several distributed low-voltage cabinets for the power distribution infrastructure.

 

Project Requirements: To ensure reliable and safe power supply throughout the entire plant area, microcomputer protection devices and arc protection devices shall be installed in all distribution rooms. Additionally, partial discharge monitoring sensors, electrical contact temperature sensors, and integrated switchgear measurement and control devices shall be installed in the high-voltage switchgear cabinets.