Mei Fei

Development and Application of Distributed Multilayer On-line Monitoring System for High Voltage Vacuum Circuit Breaker

On-line monitoring system is important for high voltage vacuum circuit breakers (HVCBs) in operation condition assessment and fault diagnosis. A distributed multilayer system with client/server architecture is developed on rated voltage 10kV HVCB with spring operating mechanism. It can collect data when HVCB switches, calculate the necessary parameters, show the operation conditions and provide abundant information for fault diagnosis. Ensemble empirical mode decomposition (EEMD) is used to detect the singular point which is regarded as the contact moment. This method has been applied to on-line monitoring system successfully and its satisfactory effect has been proved through experiments. SVM and FCM are both effective methods for fault diagnosis. A combinative algorithm is designed to judge the faults of HVCBs operating mechanism. The systems precision and stability are confirmed by field tests.

On-line fault diagnosis model for locomotive traction inverter based on wavelet transform and support vector machine

Abstract A traction inverter is the power source for rail transit vehicles. An insulated-gate bipolar transistor (IGBT) is the primary component of a traction inverter. IGBT faults can cause serious problems in locomotive power supply systems. The disadvantage of traditional fault detection methods for IGBT modules is a lack of real-time processing and high efficiency. An on-line fault diagnosis method based on a wavelet transform and multi-classification support vector machine (multi-SVM) is proposed for IGBT faults. Wavelet decomposition is used to process fault current signals, and energy vectors are constructed. Multi-SVM is used to establish a fault recognition model. The validity of this method is verified by simulations with MATLAB/Simulink.

Research on a Multilayer Distributed Online Monitoring System of 10kV High Voltage Switchgear

In order to meet the requirements of on-line monitoring for 10kV high voltage switchgear, a design of data acquisition, processing and communication based on a multilayer distributed structure is proposed. This system is composed of data acquisition and communication unit, distributed monitoring unit and remote monitoring terminal, with Ethernet communication scheme to enhance transmission rate and interoperability. Advantages of ARM and FPGA in the on-line monitoring field are explained, and on this basis a dual-core embedded main control unit is designed. The Timing control of FPGA to receive multi-channel data and the hardware and software settings in ARM to send data by Ethernet are detailedly introduced. The Ethernet packets sent by ARM are received by the industrial personal computer, which is responsible for the man-machine interface and data storage. Experiment shows that several electrical and mechanical variables can be real-time monitored by this system. The systems stability and accuracy in data processing are also verified in the experiment.

Research on a Modified Judgment Method of the Closing Moment for On-line Monitoring System of High Voltage Circuit Breaker

High voltage circuit breaker (HVCB) is a sort of important control and protection equipment in the power system. An on-line monitoring system for HVCB is designed and developed to improve the stability and reliability of power system. It can collect and save useful data when HVCB is running, gain electrical and mechanical characteristic parameters and provide effective conclusion of fault diagnoses. Therefore, it is able to provide necessary information for condition-based maintenance. In all parameters, the closing moment is very important and difficult to distinguish. A modified judgment method of the closing moment is proposed and software is designed for on-line monitoring system. This method is proved to be effective and practical through experiments.