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The fault rate of on-load tap-changer (OLTC) has always been in a high level, and that is exactly the primary reason of transformer faults. As a result, an on-line detection method of OLTC was proposed. The embedded platform and wireless sensor network (WSN) technology was introduced into the on-line detection system. WSN was used to obtain OLTC status information. The embedded platform software,...
Mechanical malfunction or failure is the principal failure type of gas insulated switchgear(GIS) within transformer substations. Therefore, on-line monitoring of the mechanical characteristics of GIS is of utmost significance to achieve safe, stable and reliable operation of power systems. a simulated GIS is constructed in laboratory and two common GIS faults like screws loosening and free particle...
Bolted joints are widely used in CNC machine tools and the presence of joint interface results in discontinuities in the local stiffness and damping of the structure, which affects the dynamic characteristics of CNC machine tools. This paper focuses on identification techniques for the nonlinear characteristics of bolted joints from experimental perspectives: (1) Time-domain methods and frequency-domain...
This paper puts forward the detecting and fault diagnosis method for GIS. The mentioned method detects and diagnoses faults by detecting abnormal vibration of the GIS. The paper gives out to diagnose the different fault types of the GIS, and make fingerprints for the GIS by monitoring these apparatus. The collected vibration signal was used in the mechanical defect diagnosis, which has proved its...
Online monitoring of the mechanical performance of onload tap changers (OLTCs) within high-voltage (HV) power transformers is of utmost significance for a safe, stable, and reliable operation of the power systems. This paper investigated a novel strategy based on a Hidden Markov Model (HMM) for mechanical fault diagnosis of OLTCs. With partition, normalization, and vector quantization of the power...
The longitudinal and torsional vibration of a lead-screw usually limits the closed-loop performance of a high-speed ball-screw drive system. It is difficult to accurately characterize the high frequency dynamics of the ball-screw drive system via a traditional lumped modeling method. This paper proposes a hybrid parameter modeling method. The model contains a distributed parameter model of the lead-screw...
Contact stiffness of machine tool joints is important but hard to be obtained. An integrated modal analysis method is proposed to obtain the contact stiffness of the joints. The method is composed of finite element method, lumped parameter method, and modal testing. By applying the modal testing data in the finite element and lumped parameter model of the whole machine tool, the contact stiffness...
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