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

The importance of having phasor measurement units or PMUs in an electric grid is widely recognized. However, the number of PMUs on a large system is limited by cost and the placement of PMUs must be addressed. The main objective of this research is to create an algorithm to identify buses that are the best candidates for PMU placement based on certain requirements. The monitoring of certain grid events like transmission line failure or generator failure must be possible from the selected PMU locations. In addition, the PMUs must be distributed evenly so that critical parts of the grid are visible. At the same time, there should be no or little redundancy in the PMU readings unless it is intentional to provide additional data reliability. The algorithm, once developed, is then applied to the electric network directed and operated by the Electric Reliability Council of Texas (ERCOT). After analyzing the results, clusters or group of buses are identified in each operational area in the ERCOT gird, where the PMUs should be located. The PMU can be located at any of the bus in the cluster. In future it is desirable to expand the algorithm to consider the geographical divisions in the ERCOT grid along with the commercial divisions.

Phasor measurement unit placement Algorithm

This paper investigates the effect of wind speed variation on short-circuit current contribution from a fixed-speed wind turbine. The focus is on fixed-speed wind turbines since this type of wind turbines can contribute fault currents as high as 6 or more times the rated current. The study is motivated by the fact that wind speed variation affects the internal voltage of the generator. As a result, if a fault occurs when the internal generator voltage is maximum, the fault current will be maximum. When the internal voltage is minimum, it will result in minimum short-circuit current. Hence, the objective in this paper is to study how significant this variation in fault current is with respect to the protective device settings calculated from the IEC 60909 Standard. Although this Standard has been developed for traditional power systems, it is a common practice to use it in networks interconnected with distributed generation. Five comprehensive case studies have been conducted. For each case study, the maximum and minimum fault current is calculated using the IEC Standard 60909 and compared with simulation results at different wind speeds.

Effect of wind speed variation on the short-circuit contribution of a wind turbine

This paper addresses to a power flow solution for AC-DC power systems. The AC system consists of transmission lines operated at 60 Hz and at low frequencies while the DC system has multi-terminal connections. The paper shows power flow in such power systems can be obtained by using the existing unified approach for AC-DC systems and reflecting impedances of lines operating at low frequencies in AC grids to their equivalent impedances at the fundamental power frequency. The equivalent transmission lines in terms of power flow of those lines operated at low frequencies are first mathematically established. The conventional unified approach to solve power flow in AC-DC systems is then discussed with a modification to reduce the size of the Jacobian matrix. The method is then verified by analyzing the power flow solution of a multi-frequency AC and multi-terminal HVDC power system modeled in PSCAD/EMTDC.

Power flow solution for multi-frequency AC and multi-terminal HVDC power systems

Novel system model-based fault location approach using dynamic search technique

Methods for benchmarking and comparison can either limit or accelerate the adoption of emerging energy storage technologies on the grid. This paper assesses the efficacy of the methods in the U.S. DOE Protocol for Uniformly Measuring and Expressing the Performance of Energy Storage to remove barriers to the technology's acceptance. The protocol enables standardized data collection to compare different technologies for energy storage applications fairly. We apply the relevant portions of the protocol to a 1-megawatt lithium-ion battery system to provide a critical assessment of procedures and methods it stipulates. Field experience and data will be invaluable to standards development organizations as they begin to consider these methods for codification.

Surya Santoso

Papers

Phasor measurement unit placement Algorithm

Effect of wind speed variation on the short-circuit contribution of a wind turbine

Power flow solution for multi-frequency AC and multi-terminal HVDC power systems

Novel system model-based fault location approach using dynamic search technique

Application of a uniform testing protocol for energy storage systems