Suitable for oil-immersed, fully sealed transformers
Enables real-time online monitoring of oil level, oil temperature, and internal tank pressure within the transformer tank, while simultaneously monitoring the water activity and moisture content (in ppm) of the transformer oil
The collected data is transmitted via RS485 to the intelligent integration terminal

Product Features
Alarm indicator with warning light; capable of indicating four alarm statuses
This product can replace traditional oil level gauges, oil temperature sensors, and pressure relief valves, providing sensor functionality for online equipment monitoring
Moisture detection: Detects changes in oil moisture content in real time to prevent insulation failure caused by increased moisture levels in transformer oil
Provides 24/7 uninterrupted monitoring, promptly reporting oil quality and tank level status
High compatibility; supports CAN-J1939 and RS485-Modbus RTU
Can directly replace traditional oil level gauges, facilitating installation
Product Overview
The JCQL-X Online Monitoring Sensor for Oil-immersed Transformers is designed for fully sealed oil-immersed transformers. It provides real-time online monitoring of oil level, oil temperature, and internal tank pressure within the transformer tank, while simultaneously monitoring the water activity and moisture content (in ppm) of the transformer oil. The collected data is transmitted via RS485 to an intelligent fusion terminal. This product can replace traditional oil level gauges, oil surface temperature sensors, and pressure relief valves, providing online monitoring and sensing capabilities for the equipment. It helps prevent economic losses caused by low oil levels, water ingress, excessive temperatures, and increased pressure in oil-immersed transformers.
Application Areas
Oil-immersed transformers.
Technical Specifications
1. Operating Environment: Temperature -30°C to +80°C, Humidity <85%.
2. Power Supply: 24 VDC.
3. Total Power Consumption: <0.5 W.
4. Oil Temperature Measurement Range: -45°C to 200°C, resolution 0.1°C; measurement accuracy: ≤±2°C for temperatures ≤100°C; ≤±2% of the measured temperature value for temperatures >100°C.
5. Oil Level Range: Distance from the oil surface to the lower edge of the tank cover: 0 to -69 mm; resolution 1 mm; measurement accuracy ≤±1.5 mm.
6. Pressure range: 80–+110 kPa, resolution 0.1 kPa; measurement accuracy ≤±1.5 kPa. Sealing pressure: ≥21 kPa; oil injection orifice diameter: Ø25 mm.
7. Moisture Detection
Water activity measurement range: 0–1 aw
Measurement accuracy:
0–0.6 ± 0.02 aw
0.6–0.9 ± 0.03 aw
0.9–1 ± 0.04 aw
Dissolved water content measurement range: 0–100 ppm; measurement accuracy: ±5%
8. Communication interface: RS485, MODBUS RTU communication protocol.
9. Mounting Thread: G1, M52×2.
10. Sensor Protection Rating: IP68.
11. Design Service Life: ≥10 years.
12. Special operating conditions and requirements shall be determined through consultation between the user and the manufacturer.
13. LED lights are used to replace the traditional color-coded liquid level alarm function; moisture, temperature, and pressure alarm functions have also been added, with adjustable alarm thresholds.
Alarm Definition:
LED Color | Red light | Yellow light | flashing red light | flashing yellow light |
Alarm Definition | Liquid Level Alarm | Moisture Alarm | Pressure Alarm | Moisture Alarm |
Wiring Definitions:
Cable colors | brown | blue | white | black |
Terminal Definitions | Power In | Power (negative) | RS485_B- | RS485_A+ |

Beijing Jiecheng IoT Technology Co., Ltd.
Phone: 18611648453 (same as WeChat)
18250846591 (same as WeChat)
QQ: 37691046
Email: 37691046@qq.com
Address: Building A, Guangxingyuan Internet Smart Technology Park, Bao'an District, Shenzhen