Active filtering of electric power has now become a mature technology for harmonic and reactive power compensation in two-wire (single phase), three-wire (three phase without neutral), and four-wire (three phase with neutral) AC power networks with nonlinear loads. This paper presents a comprehensive review of active filter (AF) configurations, control strategies, selection of components, other related economic and technical considerations, and their selection for specific applications. It is aimed at providing a broad perspective on the status of AF technology to researchers and application engineers dealing with power quality issues. A list of more than 200 research publications on the subject is also appended for a quick reference.

A review of active filters for power quality improvement

http://ieeexplore.ieee.org/iel5/5610941/5624686/05624745.pdf

Power electronics

This paper presents an optimal power management mechanism for grid connected photovoltaic (PV) systems with storage. The objective is to help intensive penetration of PV production into the grid by proposing peak shaving service at the lowest cost. The structure of a power supervisor based on an optimal predictive power scheduling algorithm is proposed. Optimization is performed using Dynamic Programming and is compared with a simple ruled-based management. The particularity of this study remains first in the consideration of batteries ageing into the optimization process and second in the “day-ahead” approach of power management. Simulations and real conditions application are carried out over one exemplary day. In simulation, it points out that peak shaving is realized with the minimal cost, but especially that power fluctuations on the grid are reduced which matches with the initial objective of helping PV penetration into the grid. In real conditions, efficiency of the predictive schedule depends on accuracy of the forecasts, which leads to future works about optimal reactive power management.

Optimal Power Flow Management for Grid Connected PV Systems With Batteries

With the fast-paced changing technologies in the power industry, new power references addressing new technologies are coming to the market. So there is an urgent need to keep track of international experiences and activities taking place in the field of modern unit-commitment (UC) problem. This paper gives a bibliographical survey, mathematical formulations, and general backgrounds of research and developments in the field of UC problem for past 35 years based on more than 150 published articles. The collected literature has been divided into many sections, so that new researchers do not face any difficulty in carrying out research in the area of next-generation UC problem under both the regulated and deregulated power industry.

Unit commitment-a bibliographical survey

The hydrogen-fueled internal combustion engine : a technical review.

Operation of power systems with high wind penetration is significantly influenced by wind variability and uncertainty. This paper examines the potential impact of distributed wind generation on ramping requirements in the IEEE 24-bus system. Wind generation and load are modeled probabilistically using actual data and curve fitting. Probabilistic unit commitment (UC) based on unit de-commitment method and two-point estimate method is used to determine the ramping required to compensate for the wind power fluctuations and load uncertainty. The proposed method considers stochastic factors and their affects on the dispatch results. Different scenarios are studied to evaluate dispersed wind generation and its potential to reduce the ramping requirement and system operation cost. Ramping requirements of the system are calculated for 24 hours day ahead scheduling period and different wind penetration levels. A brief analysis is also carried out regarding the system operation cost and the potential reduction of this cost due to dispersed wind generation.

Ramping requirements and operation cost in a power system with dispersed wind generation

Operation of the power systems with high wind penetration is significantly influenced by wind variability and uncertainty. This paper examines the potential impact of distributed wind generation on operating reserve requirements in the IEEE 24-bus system. Wind and load are stochastically modeled using actual data from a balancing authority. Probabilistic optimal power flow based on the two point estimate method is used to determine the reserve required to compensate for the variable wind power output. The proposed method considers stochastic factors and their affects on the dispatch results. Different scenarios are studied to evaluate dispersed wind generation and its potential to reduce the reserve requirement and transmission congestion cost. Correlation between the power outputs of different wind farms and wind penetration level are considered as determining factors when choosing wind sites for distributed generation. The effect of this factor on the operating reserve requirement is assessed in this paper. A brief study is also carried out regarding the transmission congestion cost and the potential reduction of this cost due to dispersed wind generation.

Operating reserve requirements in a power system with dispersed wind generation

Electric utility companies curb their system peak power demand through numerous Demand Response (DR) programs, such as the Time-Of-Use (TOU) rates where the cost of energy is typically much higher during the peak period and lower for the rest of the time relative to the standard flat rate. Meanwhile, a vertically installed West-facing bifacial PV array is expected to provide an advantage over a conventional South-facing orientation as it receives more sunlight during the period of high energy cost. This article evaluates the performance of a 1 kW bifacial PV array under different orientations while considering two energy rate options provided by the local power provider (a flat fixed rate and a TOU rate). Actual data collected during the 2011 and 2012 summer months, and numerical simulations using typical meteorological year data of the local region suggest that re-orienting the array to face west during the summer period does not result in any significant cost savings.

Economic evaluation of energy produced by a bifacial photovoltaic array in the era of time-of-use pricing

Industrial power systems are often characterized as large consumers of reactive power and significant generators of harmonics because most of the load is generally composed of induction motors and static power converters. Consequently, this article analyzes a typical power system configuration where is it desirable to install power factor capacitors and tuned harmonic filters for reactive power compensation and harmonic control. The resonant conditions for a given power factor correction or a harmonic frequency are determined directly from the roots of a quadratic expression. This formulation also allows a quick evaluation of power factor range with excessive harmonic levels, as well as effects of tuned reactors on the resonant frequencies. >

Power factor and harmonic compensation in industrial power systems with nonlinear loads

Electric power generation by means of photovoltaics (PVs) has seen an explosive growth worldwide over the past decade. This growth is driven in part by a global concern about climate change, the adoption of renewable portfolio standards, government rebates and tax incentives, and reduction in PV system cost. This article presents the basic theory on how a silicon-based PV cell converts sunlight into electricity. Silicon material and sunlight properties are reviewed with emphasis on the amount of energy that is needed to free valence electrons (i.e., bandgap) and energy content of sunlight throughout the solar spectrum. The need to add impurities to form n-type and p-type materials, for the purpose of separating the free electrons from the holes left behind, is clearly addressed. The electrical characteristics of a p–n junction solar cell are described in terms of drift and diffusion currents and the strength of the electric field that appears across the depletion region. Owing to their similarities, the equivalent circuit model of the cell when exposed to sunlight is derived from that of a p–n junction diode. The impact of changes in the numerous variables that appear in the circuit model, on the cell current–voltage (I–V) curve and power conversion efficiency, are reviewed, along with the building blocks that make up a solar PV module.


Keywords:

solar spectrum;
semiconductor materials;
doping;
diode circuit model;
cell efficiency

Yahia Baghzouz

Papers

Ramping requirements and operation cost in a power system with dispersed wind generation

Operating reserve requirements in a power system with dispersed wind generation

Economic evaluation of energy produced by a bifacial photovoltaic array in the era of time-of-use pricing

Power factor and harmonic compensation in industrial power systems with nonlinear loads

Basic Photovoltaic Theory