Sadrul Ula

Instantaneous stator power as a medium for the signature analysis of induction motors

Preventive maintenance of electric drive systems with induction motors involves continuous monitoring of operation, to detect electrical and mechanical conditions that may lead to a failure. Intensive research efforts have, for some time, been focused on motor current signature analysis (MCSA). MCSA techniques utilize results of spectral analysis of the stator current of an induction motor to diagnose abnormal conditions both in the motor and driven system. Reliable interpretation of the current spectra is difficult, as distortions of the current waveform caused by abnormalities in the drive system are usually minute. In this paper, an alternate medium for motor signature analysis, namely the instantaneous stator power, is proposed. It is shown, both by computer simulations and laboratory experiments, that the instantaneous power carries more information than the current itself, since not only the current magnitude but also the phase shift between the current and voltage waveforms are affected by irregularities in the motor or other parts of the drive system. Utilization of the instantaneous stator power as a medium for signature analysis opens new possibilities in the automated diagnosis of induction motor drives.

Comparative Evaluation of HVDC and HVAC Transmission Systems

Alternating current (AC) is the main driving force in the industries and residential areas, but for the long transmission line (more than 400 miles) AC transmission is more expensive than that of direct current (DC). Technically, AC transmission line control is more complicated because of the frequency. DC transmission does not have these limitations, which has led to build long HVDC transmission lines over the last 40 years. HVDC technology made possible to transfer bulk power over long distances. This paper presents a comparative evaluation of HVDC and HVAC transmission systems.

Comparison and evaluation of three main types of wind turbines

Many different types of wind turbines have been connected to the power systems of the world in recent years, and their primary focus was to design them to be more efficient and reliable. In this paper, three main types of wind turbines are modeled and compared. The performances of these wind turbines during a severe three-phase fault at the end of a transmission line are simulated and their characteristics are analyzed. Finally the operation and maintenance costs of these wind turbines are discussed and proper applications of these wind turbines are pointed out.

Rapid Control Prototyping of a Permanent Magnet DC Motor Drive System using dSPACE and Mathworks Simulink

Prototyping is the key step in the manufacturing industry to save time and effort. Successful prototyping needs efficient processes and systems that integrate all necessary development steps. dSPACE offers an efficient rapid control prototyping process for any industry dealing with feedback control. The objective of this paper is to demonstrate a well-documented procedure of rapid control prototyping of a permanent magnet DC (PMDC) motor drive for speed control using dSPACE and Mathworks Simulink. The combined tools of Simulink and dSPACE provide the means for modeling the controller in software and applying it to the actual hardware via a digital signal processing board. This paper presents a comparison and analysis between the simulation results and dSPACE/ actual hardware results, which agreed with each other except for some minor differences.

Wind Energy Resources in Wyoming and Simulation for Existing Grid Connection

Many wind turbines are connected to power systems in the U.S. in recent years in order to reduce the negative environmental impacts of conventional electricity generation and promote the green energy initiative. This paper presents potential wind energy resources in Wyoming and the simulation for an existing grid connection. The wind data and the potential wind power were analyzed and the wind turbine was selected according to the results of analysis. Then the performance of the wind turbine incorporating in power network was simulated using MATLAB/Simulink for steady state and fault conditions. Finally cost benefit assessment and environmental impacts were evaluated

Power system transient stability analysis software tool for an undergraduate curriculum

This paper describes, a technique of the transient stability assessment, known as the Extended Equal Area Criterion (EEAC) as applied to a multimachine power system. The EEAC is implemented using the MATLAB program to provide a software tool with GUI. The software tool of the EEAC is developed to incorporate the transient stability analysis, into an undergraduate curriculum in power engineering. Another criterion for developing this software is to reduce the effort normally associated with the instruction of the complex theory of the transient stability and the use of the software in an undergraduate classroom environment. The results obtained from the MATLAB software on two multimachine power systems are compared with the traditional time domain analysis technique for verification purposes.

Wind power availability and increased capacity credit for multiple wind farms

Due to its intermittent nature, integrating large quantities of wind power in power systems has serious impacts on power system operation. Wind power increases the load variation and the reserve requirements for contingencies. Utilities are especially concerned about the wind power availability during the peak load demand time. Conventional generation can obtain capacity credit because they can produce “firm” power during the peak load demand time. As wind power is intermittent it is normally given zero or small capacity credit. In this paper, the wind variation and capacity credit for multiple wind farms distributed in Wyoming are analyzed based on actual wind data. Considering multiple wind farms as part of one big wind farm distributed over a large area can decrease the wind power variation and increase the capacity credits. As the method used here to calculate capacity credit is the same one used by electric utilities, the potential for awarding more capacity credit to multiple wind farms is very good.

The Role of Wyoming's Energy in Solving National Electricity Crisis

Recent electric power shortages in various parts of the US stimulated a peak on generation capacity additions during the first three years of this new century. Most of the newly added units are fired by natural gas, a clean but expensive energy resource. The rapid increase in the use of natural gas makes its price ever increasing and volatile. Coal-fired plants are expected to be more promising for providing cheaper electricity in the near future. Coal will continue to be the primary energy source in electricity generation at least through 2030. Wyoming is the largest coal producing state and one of the largest in natural gas production in the US, but local utilization is extremely low. In addition to exporting raw energy resources, Wyoming could help the nation to solve its electrical energy crisis better by exporting energy directly using high voltage DC (HVDC) lines. The current electrical energy situations of the US and Wyoming are examined and some transmission schemes are proposed in this study. Economic analysis of the proposed schemes is also performed

Investigation on Fuzzy Logic-Based Self-Tuning Current Controller Applications in HVDC Links

This paper describes the effect of different defuzzification methods (DFMs) and membership functions (MFs) on the fuzzy logic-based self-tuning current controller applications in an HVDC link. The OGRE HVDC Benchmark system and control features are modeled using the SimPowerSystem toolbox and the available blocks in the MATLAB/SIMULINKreg. The fuzzy logic-based self-tuning controller is designed using the fuzzy logic toolbox in the MATLABreg. A comparative study is conducted between the fixed-gain controller and the fuzzy tuning controllers. This paper also presents the effect of the number of rules on the fuzzy logic-based self-tuning controller in an HVDC link. The results reveal that fuzzy tuned PI controller recovers the system from the faults faster than the traditional PI controller with fewer oscillations, and consecutively has less commutation failures.

Wind Data Acquisition and Analysis for a Large Wind Farm in Wyoming

Wind power is the most economic renewable source for large scale electric generation in recent years. The wind power capacity in the U.S. is increasing rapidly. This paper presents the process of analyzing wind data measured in eastern Wyoming. Mean wind speed, wind speed distribution, wind rose, and shear factor are discussed. Then environmental impacts and economic benefits are evaluated. Finally a conclusion is drawn that this project is feasible, good for the environment, and economically attractive.