Papers by Keyword: Condition Monitoring System

Abstract: The temperature of transmission line is an important parameter in the condition monitoring system on transmission line and its measured value is affected by the state of sensors. General regression neural network (GRNN) was used to construct an auto-detection network for temperature sensors of transmission line. Optimizing design of network, error controlling and effect testing were studied, and also a method of threshold for sensor detection was advanced. The network is verified by practical data from a 220kv transmission line in Sichuan Province and is proved to be with good value of engineering application for sensor state detection of unit.

Abstract: Systematic approach for the transmission line positive sequence parameters, temperature, and sag based on wavelet analysis to detect error is developed in this work. Unbiased (random/Gaussian) error such as, transient meter failures, transient meter malfunction, and measurements captured during system transients, are inherently in the form of large abrupt change of short duration in a measurement-sequence. These should be detected before the data is used because their presence will lead to insecure and unstable of power grid. The test results of the proposed method based on data of Sichuan power grid are presented.

Abstract: Speed signal is an important monitoring signal in Steam Turbine Condition Monitoring And Fault Diagnosis(TDM) system. A review on the existing speed measurement methods of rotary machine was proposed to find out the defects of each method. A new approach was introduced to fulfill steam turbine speed accurate measuring. The periods of phase signal pulse generated by the key groove and speed signal pulse generated by the velocimetry gear, were measured respectively by the two independent 16-bit timer/counters, and the "counter overflow" problem was resolved by calling a byte memory unit. According to the record number of the counter, the value of steam turbine speed was calculated accurately. The method of steam turbine speed measurement proposed in this paper can not only simplify the structure of a TDM system, but also reduce its cost.

Abstract: As an important means to improve the reliability of complex manufacturing systems and to ensure that they can function better, condition monitoring systems (CMS) are usually designed and used in manufacture industries. And reliability is one of the most important characteristics of CMS. Fuzzy set theory based on reliability modeling and analysis methods for CMS are proposed in this paper. The methods include a fuzzy graph modeling technique for analyzing the system reliability of CMS, and fuzzy reliability computing methods to quantify uncertainties in function decomposition of CMS and compute system reliability of CMS by invoking Fuzzy-set theory and approaches. On the other hand, the fuzzy reliability of CMS based on fuzzy failure subset and confidence level is defined, and system reliability indexes of CMS are set up to compute the system reliability of CMS. A case of application is used to illustrate the procedure.