A smart system for vacuum interrupts inner pressure on-line condition monitor based on Zigbee

Vacuum circuit breakers (VCBs) have operated successfully in medium voltage distribution system to control and protect power lines and power equipments. Once a VCB is unable to interrupt or make current as designed, heavy losses would be brought about to both the power system and the consumers. Inner pressure of vacuum interrupts (VI) is one of the most important parameters for VCBs´ safe and steady function. The purpose of this research is expressly put the emphases on vacuum interrupts inner pressure on-line condition monitor and its implement methods. A discriminative, applicable and reliable system to monitor the inner pressure status of VCBs in service is provided. Based on microcontroller MC9S08QE8 made by freescale and Zigbee an algorithm for internal pressure of vacuum interrupters on-line condition monitoring system is introduce, which adopt the universally accepted approach of the coupling capacitance method to detect the internal pressure of vacuum interrupters. The feasibility and validity are also presented in the research. And the installation and operation in substation and power plant in China for several years has shown the capability of EMC and stability of the system.