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This study analyzes the vibration signals of the 10 most common motor fault types.Extension theory and NN are combined to build the motor fault diagnosis system.The proposed motor fault diagnosis system is fast, requires less training data.The proposed fault diagnosis system exhibits first-rate identification capability. This study analyzes the vibration signals of fault induction motors for establishing an intelligent motor fault diagnosis system by using an extension neural network (ENN). Extension theory and a neural network (NN) are combined to construct the motor fault diagnosis system, which identifies the most likely fault types in motors. First, the vibration signal spectra of the 10 most common fault types are measured and organized into individual motor fault models. Subsequently, according to the motor fault data, representative characteristic frequency spectra are identified, and the correlation between the motor fault types and their corresponding characteristic frequency spectra are established to develop the motor fault diagnosis system. Finally, the test results confirm that the proposed motor fault diagnosis system is fast, requires less training data, and demonstrates first-rate identification capability.

This paper presents a novel 3-kW three-bladed vertical-axis micro-hydro turbine (VAMHT) system. The experimental results reveal that using this type of turbine in water is distinct from using it in wind. The micro-hydro turbine system uses a three-phase permanent magnet symmetric generator that transforms mechanical energy into electrical energy. The output voltage and frequency of the generator depend on water flow speed, and voltage steady equipment is used to maintain the maximum output power of the DC bus. According to the maximum power point tracking of the micro-hydro turbine system, the condition monitoring of the novel micro-hydro turbine requires no water flow meter. Furthermore, the construction and installation of the new micro-hydro turbine is simple, economical, and stable. This system combines a micro-hydro generator and electrical state-monitoring system, which can measure the speed, output power, DC-bus voltage, and all electrical characteristics of the micro-hydro turbine system. The results of comparing turbine between wind and water show that the speed ranges of water flow is narrower than that of wind, and the status transformation from cut-into stable power generation is short.

This study presents a multivariable linear generator which can convert wave energy directly into electrical energy. Based on the varying induction segment length over time, this study established an operational simulation of the multivariable linear generator while simultaneously constructing a multivariable generator device that considers the relationship between the number of vertical movements, the change in induction coils, the magnetic flux density, and other coefficients. Using finite element analysis, this study then analyzed the magnetic flux distribution for a single-stem linear generator and optimized the wiring. This method can be used to determine the wiring direction and coil thickness. The attraction between the magnet and the iron core is used to overcome the alternating magnetic fields, and linear motion with less stress is used to generate power. The generator developed in this study can generate 21.21 W power in 0.36 square meters area. We built a low cost, simple structure and multi-purpose human kinetic energy linear generator first for demonstration.

This study proposes a novel method using Jiles-Atherton model parameters to identify small fault current results from winding turn-to-turn short circuit in power transformer inrush current. The waveform symmetry and hysteresis curve shapes of inrush current with fault current are different from inrush current without fault current; that means the magnetic parameters of transformer cores and windings are influenced. Moreover, cycle leakage inductance and cycle winding resistance also can be used to distinguish inrush current and internal fault current due to changes of permeability and the winding current density caused by transformer core or winding state changes. Jiles-Atherton parameters per cycle, leakage inductance per cycle, and the winding resistance per cycle are estimated from the exciting inrush current per cycle under no-load conditions using the differential evolution algorithm. This study uses two types of parameters: the first is the correlation coefficient of Jiles-Atherton parameters of a transformer under no-load exciting condition. The second type is the variation trend of the cycle leakage inductance and the cycle winding resistance. The study uses cross validation of the two methods to distinguish whether inrush current contains small fault current. The experiment has verified the feasibility and accuracy of the proposed methods in this study.

Long-term voltage records of coupling capacitor voltage transformers (CCVTs) indicate that CCVT voltage is occasionally distorted under normal operating conditions. Serious voltage distortion in CCVTs can cause the protection relay to trigger a circuit breaker (CB). This work analyzes the reasons accounting for voltage distortion of CCVTs and the impact of voltage distortion due to deterioration of gap insulation in CCVTs. In this work, the CCVT parameters are measured by using an LCR meter in a power laboratory. The electromagnetic transients program/alternative transients program software is used to establish a CCVT model. Finally, the simulating results are compared with the test records to confirm that voltage distortion is caused by an instantaneous short-circuit fault in the CCVT gap. Additionally, simulation analysis confirms that a permanent short-circuit fault at the gap burns the damping resistor in the CCVT, and the protection relay warns of a burden voltage drop at the secondary side of the potential transformer.

The subject of this paper is to construct a current- transformer (CT) model based on the Jiles-Atherton (J-A) theory of ferromagnetic hysteresis using transient analysis of control systems (TACS) functions within the electromagnetic transients program (EMTP) in a closed-loop manner. The J-A theory of ferromagnetic hysteresis is presented by the nonlinear first-order ordinary differential equations and inclusive of five parameters that can be found by measurements of hysteresis characteristic. We can use TACS functions within EMTP to describe the J-A theory of ferromagnetic hysteresis. The powerful advantage of this way is the interaction between the electrical network and TACS in EMTP. Compared with the CT model based on the type 96 nonlinear hysteresis inductor, the simulated result of the CT model based on the J-A theory of ferromagnetic hysteresis is almost the same in steady-state situations, but apparently different in a fault transient situation. The analysis and simulation of the actual measured fault profiles in the Taiwan power system is an example of the validation of this proposed model. Therefore, this proposed CT model based on the J-A theory of ferromagnetic hysteresis has the analysis capability of the transient response. The flexibility of TACS makes the simulation of any other situation easier and is another advantage.

This study aims to establish equations for energy consumptions of Taiwan Railways Administration (TRA) trains in operation considering the variations of slope to determine the traction energy cost (TEC). Where railway transportation has been one of the important means of transport for mankind, since TRA became electrified the parameters for train operations have been able to be accurately recorded. The equations for overall energy consumption and resistance parameters are completed for the overall energy consumption of TRA trains and resistance to them to simulate the operation of the whole train model. The inputs of different conditions of trains and track sections are then analyzed for energy use, as the energy use by train travel is obvious. That by the behavior of energy use, can be divided in three conditions for analysis which is acceleration, coasting and deceleration. In the analysis of the energy in the journey, the variation of its consumption is subject to multiple factors because of the difference in operation model and the variation in the track slope data. In view of decreasing unnecessary energy consumption, the equations for train energy consumption and the track parameters are substituted in the teaching-learning-based optimization (TLBO) technique, which can compute the optimal results fast. The optimal results being incorporated in the trains can help reduce unnecessary energy consumption and errors by human operations and arrive at the destination on schedule. By the equations for energy consumption, train parameters, and TLBO, our study proved to be able to reduce energy use as well as ensure of Top Transport Time Expenditure (TTE) of the trains.

In a transformer, the harmonic model is essential for the filter design and analysis of harmonic power flow. Among all of the harmonic analyses of nonlinear devices, the core nonlinearity caused by the transformer hysteresis has received the most interest. Although many harmonic models have been proposed to interpret the nonlinearity of the transformer core, most of them require complex calculations. In this study, we derive the mathematical formulas of the exciting current for a single-phase transformer by the describing function methods. The mathematical expression allows us to obtain the Fourier series for the exciting current; and, then, it provides the various order harmonic magnitudes and phase angles of the exciting current. This work also presents a mathematical model characterized by simple calculation and with high precision for the harmonics of exciting current. The transformer is under no load condition. Actual measuring verifies the effectiveness of the proposed model.

A computer algorithm which combines several variance reduction techniques to enhance the precision of Monte Carlo production simulation is designed. The techniques included are stratified and antithetic samplings and linear regression estimation. For stratified sampling, a mathematical rule which can always lead to a near-optimum stratification is presented. The variance reduction by modelling generating units' outage according to their uptime/downtime distribution in comparison with modeling by forced outage rate is investigated. Numerical test results achieved by applying the algorithm to cost and environment evaluations in an actual Taiwan power system are examined. >

The harmonic current of the Le Blanc transformer of the Taiwan railway system is measured to determine how it reduces the power supply capacity to the trolley (nonlinear load). Improvements to the harmonic current in point-of-common-coupling (PCC) after adding the double-tuned filter to the load side, are also described.

The western Taiwan railway transportation system consists mainly of a mountain route and ocean route. The Taiwan Railway Administration (TRA) has conducted a series of experiments on the ocean route in recent years to identify the possible causes of unknown events which cause the trolley contact wires to melt down frequently. The conducted tests include the short circuit fault test within the power supply zone of the Ho Long substation (Zhu Nan to Tong Xiao) that had the highest probability for the melt down events. Those test results based on the actual measured maximum short circuit current provide a valuable reference for TRA when comparing against the said events. The Le Blanc transformer is the main transformer of the Taiwan railway electrification system. The Le Blanc transformer mainly transforms the Taiwan Power Company (TPC) generated three phase alternating power supply system (69 kV, 60 Hz) into a two single-phase alternating power distribution system (M phase and T phase) (26 kV, 60 Hz) needed for the trolley traction. As a unique winding connection transformer, the conventional software for fault analysis will not be able to simulate its internal current and phase difference between each phase currents. Therefore, besides extracts of the short circuit test results, this work presents a EMTP model based on a Taiwan Railway substation equivalent circuit model with the Le Blanc transformer. The proposed circuit model can simulate the same short circuit test to verify the actual fault current and accuracy of the equivalent circuit model. Moreover, the maximum short circuit current is further evaluated with reference to the proposed equivalent circuit. Preliminary inspection of trolley contact wire reveals the possible causes of melt down events based on the simulation results.