| The protection and monitoring device for the auxiliary power system is very important in the relay protection. Its performance influences the reliability of the auxiliary power system directly. But in nowadays, the protection for the auxiliary power system is still a weak link. Based on comparing the development of the protection and monitoring device for the auxiliary power system home and abroad, this paper presents a novel design scheme of its system. The hardware platform of the scheme is composed of advanced 32-bit embedded microprocessor unit and high-precision 16-bit A/D. And in the design of its software, the method based on multi-task real-time operating system is adopted. This device can not only satisfy the protection needs of auxiliary transformer low-tension side, but also meet the needs of middle and low voltage substation. A new protection principle has been utilized to recognize the start-up current and the short circuit current in feeder line protection. Through analysis and comparison, it is concluded that the scheme takes on such distinct merits as advanced system, high reliability, being apt to develop, maintain, upgrade and extend etc.. |
