Papers by Keyword: On-Line Monitoring

Abstract: Based on open NC system architecture, embedded condition monitoring and diagnosis units were studied with the characteristics of modularization and reconfigurable. The intelligent measurement and control unit can be used to on-line monitoring, fault early warming, intelligent diagnosis and remote maintenance, it provied a solution for group integration monitoring system construction of high-grade NC machine. In this paper, the implementation and function of the intelligent measurement and control unit were introduced from 4 aspects including whole framework, hardware, software and XPE OS. An example of cutting force on-line monitoring were given, which operate well for alarming in unstable cutting condition.

Abstract: This paper presents the development of on-line monitoring for condenser type bushing of power transformer in order to detect a degradation of bushing and to provide the alarm before bushing failure. For the bushing degradation analysis, the capacitance and power factor of bushing internal insulation are on-line monitored and measured by installing the sensing device at the test tap of bushing. The changing of internal insulation capacitance leads to the change of voltage across tap capacitor and the change of leakage current through bushing insulation at the test tab. Such changes result in the change of power factor or phase angle of leakage current. Thus, the leakage current is additionally detected by installing the Hall Effect sensing device to observe the trend of bushing failure. A total of eight cases of both normal and degraded insulation are investigated. The internal insulation capacitance as well as the magnitude and phase angle of three phase leakage current were measured and compared with the commissioning value or observed the increasing trend to set the alarm level. In case of degraded bushing, the leakage currents changed and caused the summation of leakage current value to be greater than the standard value. Then the alarm is activated. This knowledge was used to develop the detection and decision making algorithms in LabVIEW program to determine the condition of transformer bushing.

Abstract: XLPE power cable is widely used in grid system for its series of merits, but the fault become more and more frequent with increase of the use of cable and longer run time. In this paper, the reasons of the fault are introduced and the on-line monitoring technique of XLPE power cables is presented.

Abstract: In view of the appearance of instability and malfunction problem for level control system in the steam drum of boiler, a new method to use statistical process control (SPC) was proposed, which analyzed the level data by the SPC. It can extract the main features of the level variable, and set up the upper and lower monitoring limits for the level control system in the steam drum of boiler. The decision-making basis for the operator can be provided by monitoring control accuracy of the level control system. With this method, it can improve the control accuracy of the level variable and provide the information quickly and efficiently for the fault diagnosis of the level control system, prevent the malfunction occurs, ensure safety and stable operation for the boiler control system.

Abstract: This paper describes the design and implementation of the on-line monitoring software system of partial discharge in GIS based on the combination of acoustic and electric in detail. The field operation experience show the system is stable and reliable which can meet the need of GIS on-line monitoring.

Abstract: The paper introduces a design scheme for the Extra High Voltage (EHV) transformer condition on-line monitoring system, which is based on the collection and analysis of the transformer winding and core vibration signals. This system is composed of vibration acceleration signal sensors and the signal analyzing computer where the collected vibration signal is saved and processed. The analyzing computer can accomplish the missions of data acquisition control, data analysis and the historical data query. Vibration characteristic values of transformer winding and core include peak to peak value, spectrum, kurtosis, and the amplitude 100Hz component and its higher harmonic components. They are extracted, and the characteristic trend curves are drawn by data analysis, so that EHV transformer on-line monitoring and fault diagnosis are accomplished.

Abstract: Experiment analyzed the main factors that affect the performance of Online Sequential Extreme Learning Machine (OS-ELM). And the experimental comparison show that the OS-ELM in classification performance is better than the support vector machine (SVM) and extreme learning machine (ELM). But there still is not a stable network output now. For this aspect, this article presents the optimization algorithm of integrated Ensemble of online sequential extreme learning machine (EOS-ELM). The algorithm using a limited number of sample data has been applied to transformer fault diagnosis. The time of training and testing can be shortened and the classification accuracy can be improved. The experimental results show that the OS-ELM has better performance in response to online monitoring and real-time data processing.

Abstract: The quality of oil determines the status and life of the devices. However, most Chinese vessels have not equipped with on-line oil quality testing facilities. Therefore, a special on-line oil quality monitoring system for vessels is designed to real-time monitor of oil pollution change. An alarm signal or control signal based on the monitoring results is sent, which supports the purifier automatically and water, particles and gases are removed from the oil to maintain a good oil quality. The system is developed and implemented in the vessel corporation and has a good prospect of application. The application of this system will promote the process of the intelligent device management.

Abstract: Water quality on-line monitoring is the necessary means to control water environment pollution and provide effective data for the research of water ecological restoration. Using free wireless communicating module of ZigBee we realized transmitting data from sensors on the river bank to the data storage center. Based on serial ports of micro-controller a protocol converter circuit was designed. With program the Modbus RTU protocol data packet on RS-485 bus was converted into ZigBee communication protocol and then transmitted to the Internet. Supplemented by GSM the reliability of data was enhanced. Water quality online monitoring system based on multiple data communication provides browse of real-time river water quality through the Internet network, which is fast and convenient to be exported for research.

Abstract: This paper studies the on-line monitoring system of transmission tower stress.Firstly, it introduces the necessary of this system, gives its system architecture. Then it presents an algorithm to determine the stress sensors' installation points on the tower, which based on finite element analysis. Through calculating the stress distribution condition of different components of the transmission tower under typical working condition, these points with relatively higher failure probability in the transmission tower can be monitored by installing stress sensors on them. Finally, it uses a 500kV oxytropis tower as an example to show the algorithm flow.