Calculation of Capacitive-Based Sensors of Rotating Shaft Vibration for Fault Diagnostic Systems of Powerful Generators

Abstract

This paper presents the results of research and development of capacitive-based sensors of rotating shaft vibration for fault diagnostic systems of powerful turbines and hydro generators. It showed that diagnostic systems with special sensors are the key to increasing the reliability of powerful turbines and hydro generators. The application of sensors in monitoring systems was considered, and the requirements for the sensors used were analyzed. Structures of concentric capacitive-based sensors of rotating shaft vibration based on the measurement of the capacitance value from the distance to the metal surface were proposed. The design scheme was created for determining electrode dimensions of the rotating shaft vibration capacitive-based sensors with concentric electrodes, and analytical dependences were obtained. The calculation results allow the selection of optimal parameters of the active and guard electrodes. Analytical and computer simulation methods determined the response functions of the capacitive sensors. Analytical calculations and simulation results using 3D FEM were used to find the response functions of the sensors. The calculation of the characteristics of the capacitive-based sensors of rotating shaft vibration is presented. The study of the influence of fringe effects was carried out using the obtained results of the modeling and analytical calculations.

Passive Wireless Vibration Sensors Based on the Amplitude Modulation of Harmonic Backscattering

“…The vibration frequency is calculated as the average frequency separation between the first sidebands and the carrier tone. Then, the duty cycle D of the waveform is determined from A 21 as described in (11). To verify the consistency of the process, the signal envelope is also recovered.…”

“…They are used to perform structural health monitoring (SHM), which is critical to predict risks by checking the wear status of equipment and infrastructures and the stress that mechanical parts are subject to [4]. Vibration sensors are based on a variety of transducers, ranging from piezoelectric and piezoresistive materials [5], [6], to micro-electro mechanical (MEMS) accelerometers [7], [8], strain gauges [9], fiber optics [10], and variable capacitors [11].…”

Some features of the systems for monitoring and diagnostic hydro units technical condition with considering smart grid technology

“…The main prerequisite for forecasting the remaining useful life prediction of hydro unit is the availability of information about the technical condition of the equipment or its components [8,9]. To obtain primary information, modern monitoring and diagnostic systems are equipped with smart sensors [10,11]. Smart sensors provide the possibility of self-monitoring, which ensures obtaining data without abnormal values, which can be used without preprocessing to determine the state of the equipment or its units.…”

Effect of Magnetic Shunts on Shell-Type Transformers Characteristics

“…The finite element method used in the calculations performed in this paper can be successfully adapted not only to electromagnetic field distribution but also to thermal [12], mechanical simulations [13][14][15], or transformer loss determination [16,17]. In addition, good compatibility is obtained not only for transformers but also for other objects, e.g., inductive sensors [18].…”