Research And Development Of The State On-line Real-time Monitoring System For Power Transformers Based On Embedded Technology

Since the beginning of the Twenty-first Century, with the rapid developments of economy,requirements on the electric energy and power quality for human society become higher andhigher, smart grid engineering and the effective use of green energy are being discussed andconstructed. Power transformer is one most important part of the power systems in the opera-tion of power transmission, its operation is normal or not, which will directly affect the powergrid safety and power quality, so it is very important to monitor and protect power transformer.This paper is committed to developing one set of state on-line real-time monitoring systemor equipments for integrated monitoring a variety of parameters of most kinds of power trans-formers, which can provide various datas for comprehensively judging the operation states ofpower transformer. The possible latent hitches of power transformer can be found timely andprecisely, and can be handled on time to avoide accidents. Comprehensive monitoring and pro-tecting are supplied for power transformer to achieve a win-win effect of equipment using andeconomic benefit.Advanced new techniques are applied to the design of the terminals to monitor differentparameters, the hardwares and softwares of the terminals are designed by using embeddedtechnology, the practical new measuring-algorithms of the terminals are designed by usingdigital signal processing technology. Four monitoring subsystems include AC parametersmonitoring subsystem, neutral point DC bias monitoring subsystem, vibration signal monitoringsubsystem, and noise signal monitoring subsystem, consist of three hardware terminals. Thewhole monitoring system is combinated with three hardware terminals by using integrationtechnology.The system can monitor a variety of parameters in real-time, which include frequencies ofthe primary and secondary side of power transformer, amptitude, phase, power factor, powerand electric energy of voltage and current of the fundamental and2to25harmonic waves, neu-tral point DC signal, vibration signal and noise signal, etc.Comparing with the sigle hardware terminal which is combinated with four subsystems, the system has obvious advantages:（1） If the hardware of one terminal has failure, others can still monitor the runningstates of power transformer in real-time, not all the monitoring parameters collapse, which re-sults in monitoring spots on the timing.（2） It requires that processor hardware has a very high performance to realize the func-tions of four subsystems on sigle terminal, three terminals realize their functions individually,the latter three processor hardwares costs are lower than the former one, and three terminals canhave using ways of flexible combinations according to different demands, and need an easiermaintenance.Finally, four monitoring subsystems or terminals are debugged individually, the accuraciesof measuring results are higher, the designings of the softwares and the hardwares and the prac-tical new measuring-algorithms of four terminals have practice verifications. The system is notonly suitable for practical applications of smart grid monitoring systems, but also is suitable fora variety of monitoring situations, which is a comprehensive monitoring system with high per-formances and multi purposes.