Research On Temperature Monitoring System For Electrical Equipment Based On Wireless Sensor Networks

Fiber fluorescence temperature measurement technology has gradually been mature by researching and exploring for many years. Its strong anti-interference ability and good insulation properties make it very suitable for applications in high voltage substations, as well as the high complexity of the electromagnetic environment. With the rapid development of the semiconductor technology, MEMS technology, computer technology and communication technology, wireless sensor network technology, the developing trend of detection and sensing technology, develop rapidly in recent years. It will have a very good prospect in application of substation automation monitoring, combining fiber fluorescence temperature measurement technology with wireless sensor network technology.Based on this idea, this paper designs a substation temperature monitoring system based on wireless sensor network.At first, this paper analyzes the principle of fiber optic fluorescence temperature sensing in theory, and selects the fluorescent material applicable to the research environment drew on previous research results. Then it discusses and analyzes some common time constant computing method, and emphatically introduces several data fitting method, and summarizes their advantages and disadvantages. Finally, according to the existing experiment equipments, it chooses least squares fitting as the data processing method. This article makes use of DASH7 protocol to realize Wireless transmission. Wireless transmission system is mainly composed by the main control chip and the radio frequency (RF) chip, in which, the main control chip is STM8L103, and the RF chip is SX1212. Compared with communication scheme based on the Zigbee protocol, this scheme has the characteristic of farther transmission distance as well as penetrating the cement wall and other obstacles, in addition, it is more economy.The paper realizes the design of temperature sensing unit. Hardware design includes the selection of fluorescent material, the choice of exciting light sources, the design of the excitation light driving circuit and weak signal amplifying circuit. Software design mainly completes the realization of the least squares method of data acquisition and processing unit. After finishing the design of wireless module, this paper tests the communication quality and distance of wireless module, and qualitative analyzes the factors which possibly influence the communication quality and distance. The experimental results show that the communication between the temperature measuring unit and the wireless modules, as well as temperature acquisition unit and PC unit, is in good condition which basically achieves the desired effect.