Reseach Of Monitoring System Of Temperature For MV Switchgear Contact Base On ZigBee

Medium-voltage switchgear is an important control and protection equipment in electric power system.it is charge with closing and breaking the electric power system and also is responsible for the safety of the electric power system, the safety and reliability of medium-voltage switchgear concerns the safety and the reliability of operation of power grid. Nowadays, with the rapidly increasing of The power supply load of electric power system, the switchgear have occurred failure sometimes. For medium-voltage switchgear, since it always works in high voltage and strong magnetic field, the switchgear contact will become loosing and old and cause the contact resistance increasing easily. In the long terms, this situation is so easy to lead the accident of temperature. So it is a serious threat to the safe and stable operation of electric power system. Since switchgear usually adopts a enclosed structure and the situation is so complex in switchgear, it is so hard to measure the temperature of switchgear contact. In order to solve the situation, In this paper, several temperature measurement methods of switchgear contact existing in domestic and abroad were compared in the first. And then to analysis the existing defects of contact temperature monitoring technology. In the end, combined with the actual situation of switchgear to design a kind of online monitoring system of temperature for medium-voltage switchgear contact which is based on ZigBee wireless sensor network technology. Besides, we solved the problem of power supply for the high-voltage side temperature collector.The whole system in hardware design, we have completed the design of the ZigBee core boards the temperature collector and coordination.The ZigBee core board is based on a system chip which is taken CC2530 as the main control chip, mainly introducing the external circuit of the core board and the design of antenna; The design of the temperature collector mainly includes the DS18B20 interface circuit USB to UART circuit and high-voltage Self-supplying power source; The design of coordinator includes JTAG debug interface circuit、RS485 interface circuits、LCD display circuit、coordinator power converter circuit、buzzer alarm and other peripheral interface circuit. Besides, the concrete measures against electromagnetic interference to the hardware design were given in this paper.The Software design is based on TI’s Z-Stack protocol stack and in the IAR Embedded Workbench integrated development environment by transplating and adding the corresponding program code to complete the software design of each node. In addition we also had an in-depth discussion on the process of realization of Z-Stack protocol stack operation mechanism and system network topology structure. Besides, the establishment of a ZigBee network and how the nodes to join the network were analyzed importantly. Finally, we realized the development of PC software by LabVIEW.In the end, the experimental test of the system was carried on. Including the high-voltage Self-supplying power source test、The communication distance test between nodes、Network test and the whole test between temperature monitoring device and PC. Besides, we used the Packet Sniffer to capture some data and did some analysis and demonstration on the network process. The experimental results showed that the designed device can realize the acquisition and transmission of temperature data of the stable and effective, measurement error within ± 1℃, The desired results have been achieved and there are some certain practical value.