There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

On robust estimation of the location parameter

In the world, wind power is rapidly becoming a generation technology of significance. Unpredictability and variability of wind power generation is one of the fundamental difficulties faced by power system operators. Good forecasting tools are urgent needed under the relevant issues associated with the integration of wind energy into the power system. This paper gives a bibliographical survey on the general background of research and developments in the fields of wind speed and wind power forecasting. Based on the assessment of wind power forecasting models, further direction for additional research and application is proposed.

A review on the forecasting of wind speed and generated power

http://pierrepinson.com/31761/Literature/foley2012.pdf

Current methods and advances in forecasting of wind power generation

In this paper we present a new approach to detect, localize, and investigate the feasibility of classifying various types of power quality disturbances. The approach is based on wavelet transform analysis, particularly the dyadic-orthonormal wavelet transform. The key idea underlying the approach is to decompose a given disturbance signal into other signals which represent a smoothed version and a detailed version of the original signal. The decomposition is performed using multiresolution signal decomposition techniques. We demonstrate and test our proposed technique to detect and localize disturbances with actual power line disturbances. In order to enhance the detection outcomes, we utilize the squared wavelet transform coefficients of the analyzed power line signal. Based on the results of the detection and localization, we carry out an initial investigation of the ability to uniquely characterize various types of power quality disturbances. This investigation is based on characterizing the uniqueness of the squared wavelet transform coefficients for each power quality disturbance.

Power quality assessment via wavelet transform analysis

2009 ASEE Annual Conference and Exposition

The operating power frequency fluctuates around its nominal value under normal conditions based on the dynamic balance between load demand and generation levels. This frequency variation creates a challenge in computing and analyzing voltage and current root-mean-square values over time, since sliding windows may not cover an integer number of cycles of the sampled voltage and/or current data. The overall objective of this paper is to present an adaptive resampling technique for the voltage and current waveforms, such that each sliding window used for computation of power quality parameters always cover an exact integer number of cycles. This technique is illustrated for a capacitor de-energizing operation, which is detected through a step change in the rms voltage profile. Once this de-energizing operation has been detected, the voltage waveform is resampled and the rms voltage profile with a high time resolution is obtained through a fast and recursive approach. Finally, the exact capacitor de-energizing instant is estimated. The proposed approach is shown to be simple, yet robust and accurate.

Root-Mean-Square Profiles under Varying Power Frequency: Computation and Applications

This paper identifies and quantifies the unique characteristics of current-limiting fuse operation as seen in the current and voltage waveforms recorded at a monitoring station located upstream from the fault. Characteristics that can be used to identify current-limiting fuse operations by visual inspection are described. More characteristics are extracted using signal processing methods. These characteristics include but not limited to the duration of the event, point on the waveform where the event starts and ends, the rate of rise of the voltage and current at the start of the event, and the thermal energy in the fuse during the event. These methods are applied to data collected by a number of utilities and the results tabulated. In the future, the results can be used to automatically classify events that are recorded by power quality monitors.

Unique waveform characteristics of current limiting fuse operations

Electrical power systems quality / Roger C. Dugan, Mark F. McGranaghan, Surya Santoso, and H. Wayne Beaty

With higher penetration of distributed photovoltaic (PV) resources and wider adoption of electric vehicles (EVs), it is reasonable to expect events at the distribution level to more actively influence the state of the network. However, traditional power flow formulations mostly consider either the transmission system or the distribution system. Recent work has been done in the development of a joint transmission and distribution (T&D) formulation to properly account for interactions between the two systems. This paper presents the analysis of effects of distribution system resources on transmission system voltages. The analysis relies on a recently developed power flow tool that combines distribution and transmission circuits. Results of multi-period power flow simulations are shown demonstrating how the location of PV and EV fast charging facilities in distribution circuits affects transmission bus voltages. Furthermore, the results are analyzed, and justifications are offered to explain the observed phenomena.

Surya Santoso

Papers

2009 ASEE Annual Conference and Exposition

Root-Mean-Square Profiles under Varying Power Frequency: Computation and Applications

Unique waveform characteristics of current limiting fuse operations

Electrical power systems quality / Roger C. Dugan, Mark F. McGranaghan, Surya Santoso, and H. Wayne Beaty

Analysis of Effects of Distribution System Resources on Transmission System Voltages using Joint Transmission and Distribution Power Flow