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In this paper, an expert-system-based load shedding scheme (LSS) for ship power systems is revisited. In this LSS, a popular decision-making tool termed the analytical hierarchy process (AHP) is utilized for prioritizing the loads to be shed onboard a notional all-electric ship power system. The AHP-based LSS is proposed as an alternative to possibly overcome some of the major drawbacks of traditional LSSs implemented on ship power systems by minimizing the number of loads disconnected, differentiating the priority of loads based on system conditions, and considering a wider ranger of factors that may potentially influence the shedding of electrical loads. An implementation of the developed LSS to a destroyer-class shipboard power system simulated on a real-time digital simulator is presented. Index Terms--Analytical hierarchy process (AHP), dynamic prioritization, load shedding, shipboard power system (SPS).

In this paper, the application of a novel time-frequency analysis tool for the online estimation of the transfer functions of a notional high-temperature superconducting (HTS) marine propulsion motor is demonstrated. A detailed simulation model of the notional HTS motor with a realistic load modeling of sea states to produce torque oscillations is utilized for the analysis. A method is presented for the online near real-time estimation of transfer functions between the torque oscillations and the concomitant variations in the field current and mechanical speed of the HTS motor. The transfer functions, obtained by using the novel method, are compared with the results from a traditional offline transfer function estimation technique. Index Terms--Empirical mode decomposition (EMD), empirical transfer function estimation (ETFE), fast Fourier transform (FFT), high-temperature superconducting (HTS) motor, Hilbert-Huang (HH) method, Hilbert transform, intrinsic mode function (IMF), sea states, ship propulsion.

The Hilbert-Huang method is presented with modifications, for time-frequency analysis of distorted power quality signals. The empirical mode decomposition (EMD) is enhanced with masking signals based on fast Fourier transform (FFT), for separating frequencies that lie within an octave. Further, the instantaneous frequency and amplitude of the constituent modes obtained by Hilbert spectral analysis are improved by demodulation. The method shows promising time-frequency-magnitude localization capabilities for distorted power quality signals. The performance of the new technique is compared with that of another multiresolution analysis tool, the S-transform--a phase corrected wavelet transform. Analysis on actual measurements of transformer inrush current from an existing laboratory setup is used to demonstrate this technique. Index Terms--Empirical mode decomposition, fast Fourier transform, Hilbert-Huang spectrum, power quality, S-transform, time-varying waveform distortions, transformer inrush current.

There are advantages of installing distributed generation (DG) in distribution systems: for example, improving reliability, mitigating voltage sags, unloading subtransmission and transmission system, and sometimes utilizing renewables. All of these factors have resulted in an increase in the use of DGs. However, the increase of fault currents in power systems is a consequence of the appearance of new generation sources. Some operating and planning limitations may be imposed by the resulting fault currents. This paper discusses a model of inverter based DGs which can be used to analyze the dynamic performance of power systems in the presence of DGs. In a style similar to protective relaying analysis, three-dimensional plots are used to depict the behavior of system reactance (X) and resistance (R) versus time. These plots depict operating parameters in relation to zones of protection, and this information is useful for the coordination of protection systems in the presence of DG. Index Terms--Distributed/dispersed generation, fault calculation, inverters, power distribution, power system protection.

This paper describes a web-based portal of peer-ranked sites on power engineering for educational purposes. It is a free and open resource consortium for faculty and students in power engineering. As the Internet is developing into a main educational tool, this multimedia-based application offers the educator and the student access to numerous power engineering resources. While it is possible to obtain information using one of the many popular Internet search engines, the results may not be relevant to the desired search topic. The portal described in this paper has individual hyperlinks to various web sites on power engineering that have previously been reviewed and ranked by both established faculty and students according to the versatility of each site. Peer-ranking influences the users' choice for extracting relevant information. Qualitative and quantitative statistical indexes are utilized to rank the web sites. Educators may use the resources available on the portal for educational purposes in a classroom setting. An analysis of the effectiveness of this portal on power engineering education is also offered in the paper. Index Terms--Internet, learning, multimedia, online, pedagogy, power engineering education, ranking, search engine, teaching.