| With the rapid development of the high-speed railway, China has built the world’s largest high-speed railway with the highest operating speed, which greatly improves China’s railway transport capacity. Once the failure of the traction power supplying equipment leads to the outage of the railway network, it will have very serious negative effects. Thus, it is of great importance to ensure the safe and stable operation of the high-speed railway.The high-voltage capacitive device is an important part of the traction power supply system, so the foundation of the traction power supply system’s safe and reliable is to ensure the normal operation of the capacitive device. Generally the power system substation and the railway traction substation make use of preventive test and equipment accidental maintenance to ensure the normal operation of the high-voltage equipment, however these two approaches both have deficiencies, for example, the way of preventive test has great blindness and costs too much which cannot find out the equipment’s hidden failure in operation. Therefore, it is necessary to develop a kind of real-time, automated, intelligent high-voltage equipment online monitoring system that can keep track of the operating status trends and provide early warning of equipment failure in order to make the overhaul much purposive and targeted. The high-voltage equipment online monitoring system is a useful supplement and development to the existing operational equipment like the telecontrol and protection, but it is through analyzing the feedback information that shows the on-line monitoring technology is not yet mature, especially for the high-speed railway traction power supply system featured of heavy traction load, frequent impact and abundant high harmonic, the stability, measurement accuracy and anti-jamming capability of the online monitoring system should to be further improved.According to research the structure of the existing online monitoring devices used for the capacitive equipment both at home and abroad, a kind of distributed online monitoring system based on the can bus was designed in this paper, constituted by the detection layer, control layer, and management layer. On the basis of the measurement methods of the dielectric loss value in the existing insulation online monitoring system and with the combination of the monitoring principle of the capacitive equipment, the digital measuring technique was used to make a further discuss and practice on the data preprocessing scheme based on the harmonic analysis method aimed at the characteristics of the high-speed railway traction substation, in addition the FFT algorithm of the system dielectric loss value was given in this paper to improve the system accuracy. Meanwhile, a synthetic diagnostic method based on the relative analysis method and trend analysis method was introduced in the system fault diagnosis, so as to obtain a better diagnosis effect.The hardware include the bushing-tap detection, the active compensation zero-flux current sensor, the CAN bus communication and the data processing unit, of which the design and improvement has been finished. Featured to a complex system working environment and severe electromagnetic interference, the protection, shielding and grounding scheme were formulated.The software using the C++as the standard developing language for the processing center in the substation and the segment workstation has been completed on the platform based on C++Builder6.0and the SQL Server2005front-end software, with the properties of a full Chinese interface, modular design, full menu operation and good human-machine interface as well as easy to operate.The system has been put into trial operation in the Dashigu traction substation. Through the analysis of the operating results obtained, it is shown that the system has strong anti-jamming capability, high accuracy and stability and can meet the requirements of engineering applications. |
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