Design And Implementation Of High-voltage Transmission Equipment Online Digital Temperature Monitoring System

National electricity system6～10KV switch cabinet accident statistics show that the fault caused by insulation and overload accounted for40.2%of the total,of which the accident due to the isolation plugs caused by poor contact accounted for over71.1percent of the total overload accident.Steel mills, refineries and processing plants have a lot of high voltage switchgear, with all kinds of electrical contacts, so failures occur frequently.Typically, by measuring the temperature change of the electrical contacts can determine the failure. This paper proposes and implements a set of wireless measurement system which measures temperature changes in electrical contact. To avert the risk of Creepage, dimensions of the measuring equipment must be strictly controlled, and this will limit the battery capacity of the measurement equipment, but also limits its antenna diversity arrangement.In addition, the high-voltage environments typically have a metal shield, this requires the wireless transmission mode must be flexible, this paper also proposes a combination of mesh and star-shaped network of heterogeneous networking solution to solve this problem,the star network has played a low-power advantages, and the mesh networking meets the flexibly and reliably.Common Zigbee protocol stack occupies20-30K of code space, not for the weak SCM. Zigbee protocol supports hardware devices typically working in the2.4GHz band, the signal which will be reflected by the steel and concrete structure becomes multiple interference,so the system selects the433M measuring baseband,433M transmission same distance when power is only Zigbee protocol2.4G baseband30%. Zigbee system encryption and decryption occupy more CPU and rely on AES coprocessor, which leads to the system power consumption and hardware costs.This design uses the XXTEA algorithm and time-based dynamic key encryption, giving up encryption on the network topology information, which also could further save power.Based on a comprehensive analysis of the Zigbee protocol, according to the system needs to be redesigned, developed a low-power but with a Zigbee flexibility of high temperature wireless protocol stack. Its support system has achieved good results in practical application Liuzhou Iron and Steel, Panzhihua Steel, Chongqing Steel and other steel companies. Since the system is running stable and reliable, it achieves the desired design goals.