Microprocessor Protection Algorithm Based On HHT And Its Platform Development

Power system relay protection is the first defense line for safe and stable operation ofthe power system. Because the not yet strong enough power system, relay protection has themost important responsibilities in our grid for its rapidity, selectivity, sensitivity. Progressand development of the relay protection technology will have a positive and significantimpact on grid operation.This article studies the microcomputer protection algorithm, which includes Fourieranalysis and wavelet analysis. It points out the advantages and disadvantages of the twomethods, by considering the measurement accuracy and filtering feature requires, it lastfocus on HHT (Hilbert-Huang transform). HHT can analyze the characteristics of theinstantaneous frequency and has the filtering ability to remove the exponentially decayingdc offset, which makes it possible to improve relay algorithm relay performance byadopting this method. After a study of the application of HHT in the power system, and bybrowsering literature and examples, this paper analyzes the characteristics and the specificthe use of the HHT method. On the foundation of the widely used MATLAB version HHTcalculation program modules, we use the latest MATLAB-stm32joint programming tools tomake the HHT algorithm program practical and feasible.In order to be able to facilitate the entire software system structures and meet thereal-time requirements, also enable the above HHT algorithm to be practical,this paperchecks the necessity and significance of adopting the embedded operating system. Afterconsidering various factors, it highlights and analysis the μC/OS-II embedded real-timeoperating system. And in accordance with the requirements of the embedded operatingsystem, the paper designed the hardware system, on which the transplantated μC/OS-IIsystem source code is running. The platform on the basis of the operating system, is built tobe a mobile, networked, intelligent software systems, such as GPS IRIG-B code timesystem, WEB browser remote monitoring system, the Ethernet remote program updatesystem. On this unified software and hardware platform, we have developed railwaytraction substation protection series, substations and power plants protection series, all ofwhich have been successfully passed type test of the national relay testing center, and havebeen put into operation in practice. It shows that the hardware and software platform of the protection device has good performance characteristics of high reliability and advancedtechnology.