Semaan Georges

Fingerprinting Localization Using Ultra-Wideband and Neural Networks

In this paper, the interest in localization is basically for security issues in a big industry that is still considered to be one of the most dangerous working places, the mines. Mines conditions make solutions based on TOA (time of arrival), AOA (angle of arrival), or even RSS (received signal strength) subject to big errors. The system we discuss relies on fingerprinting technique to overcome those inconveniences. The use of UWB with its high temporal resolution and its multipath beneficial properties will constitute the basic pillar in overcoming much of indoor localization problems. Neural networks with their interpolation characteristics have the role of replacing any database correlator (or search engine) that usually exists in fingerprinting techniques. Measurements of the channel response in the investigated medium, in addition to the choice of the appropriate parameters, will be explored. Evaluation of the neural network performance and comparison with other indoor techniques will help identifying the utility of the proposed system. Finally, future work to be done will be described.

Simulation of a hybrid renewable energy system in rural regions

This paper presents the design of a MATLAB simulator of a hybrid renewable energy system applied for energy generation in rural regions. The system is simulated using MATLAB. It consists of a set of photovoltaic panels, a DFIG wind farm, a pumped water storage/generation station and it is designated to supply residential/industrial loads. A transmission line connects this system to the main power grid. Although conventional models are used, the work originality consists of performing an optimal control of sources and loads in order to keep power balancing between generation and consumption in both connected and islanded modes.

A linear decoupling control for a PWM three-phase four-wire shunt Active Power Filter

The presence of current harmonics in the grid causes major problems such as overheating and electromagnetic emissions. Active Power Filters (APF) have been presented as alternative to reduce such harmonics. In this paper, a new constant-frequency control scheme based on the linear decoupling principle is proposed for a shunt three-phase fourwire APF. The APF is used to compensate the current distortion and the reactive power created by a typical industrial load. The elaboration of the control law is based on a small-signal averaged model of the converter, computed in the (d,q,0) synchronous frame. The control scheme consists of multiple-loops regulators that ensure voltage regulation at the DC side of the filter, and current wave shaping at the AC side. The control system is implemented numerically using Matlab/Simulink tool. The performance of the proposed control approach is finally discussed through the obtained simulation results.

Fast processing of resistivity sounding measurements in N-layer soil

This paper presents a new method and derives the theoretical equations for calculation of the apparent resistivity standard curves of horizontally multilayered models. For known earth parameters, the apparent resistivity distribution can be computed efficiently by this method. The profile of the apparent resistivity calculated with Schlumberger electrode arrangement for an arbitrary number of layers is presented. However, to prove the reliability of the present method, the apparent resistivity of given three to five layer models is calculated for the Wenner array using existing methods and the presented one. Also, this paper uses an inversion method to find the electrical grounding parameters of an N-layered earth (resistivities and thicknesses) corresponding to a specific mathematical model. Parameters estimation is carried out in such a way as to get a fitting between the set of resistivity values measured by means of Schlumbergers method, and those calculated from the mathematical model using such parameters.

Modelling and Comparative Evaluation of Control Techniques Applied to a PWM Three-Phase Four-Wire Shunt Active Power Filter

Current harmonics, which are injected in the utility by nonlinear loads, cause major problems that tend to deteriorate the power quality at the mains. To reduce such harmonics, active power filters (APF) are commonly employed. In this paper, two multiple-loops control schemes for a shunt three-phase four-wire APF are considered. The APF is used to compensate the current distortion and the reactive power created by a typical 60 kW industrial load. The first control scheme is based on the use of hysteresis current controllers for the current wave shaping, whereas the second one employs linear PI regulators designed on the basis of a small-signal averaged model of the converter. Both control schemes are designed to ensure voltage regulation at the DC side of the filter, and current wave shaping at the AC side. The control systems are implemented numerically using Matlab/Simulink tool. The performance of the both control approaches are finally evaluated and compared through the obtained simulation results

Evaluation of the effect of salt water and a counterpoise on the voltage profile of a HV power transmission line grounding system in a two layer with high resistivity soil

Soil resistivity plays a key role in designing grounding systems of high voltage transmission lines and substations. This paper deals with an already in service HV utility, it is a 69 kV transmission line with a power generation plant at one end and a transformation substation at the other. What makes this case very interesting is that this installation is located in a high soil resistivity area, at the same time as being in the vicinity of sea water with very low resistivity. It belongs to Hydro-Quebec and does not have a shield wire nor counterpoise. This research highlights the impact of the salt water in reducing the potential rise during an electrical fault and the effectiveness of the counterpoise when the resistivity of the soil is very high. The method of images from electromagnetics is applied to calculate the potential rise. All results are validated by experimental measurements performed by a specialized field test group from Hydro-Quebec.

An Efficient Approach for Shorterm Load Forecasting using Artificial Neural Networks

In previous work, we applied artificial neural networks (ANN) for short term load forecasting using real load and weather data from the Hydro-Quebec databases where three types of variables were used as inputs to the neural network: a) hour and day indicators, b) weather related inputs, and c) historical loads. In general, for forecasting with a lead time of up to a few days ahead, load history (for the last few days) is not available, and therefore, estimated values of this load are used instead. However, a small error in these estimated values may grow up dramatically and lead to a serious problem in load forecasting since this error is fed back as an input to the forecasting procedure. In this paper, we demonstrate ANN capabilities in load forecasting without the use of load history as an input. In addition, only temperature (from weather variables) is used, in this application, where results show that other variables like sky condition (cloud cover) and wind velocity have no serious effect and may not be considered in the load forecasting procedure

Voltage regulation of electric power network interconnected with wind energy distributed generations

The large scale connection of power generation in distribution networks causes deregulation in power system networks. This paper focuses on studying the voltage changes at each node of the distribution network before and after the insertion of wind turbines as power generators, and also proposes two optimal voltage control methods in order to maintain a stable voltage profile. Results of the simulations are presented in order to confirm the proposed ideas and assert the effectiveness of the used regulators as well as their optimal capacity control.

Interpretation of Resistivity Sounding Data for Multi-Layer Vertical Earth Model

Soil resistivity plays a key role in designing grounding systems for high-voltage power transmission lines and substations. The objectives of this paper consist of computing the best estimated value of the apparent resistivity and the electrode grounding resistance of a vertical N-layer soil. Then, earth parameters are precisely calculated by applying an inversion method. The inversion method is useful to estimate soil parameters from Schlumberger measurements. Four theoretical models are selected in order to validate and test the inversion scheme of the method.

Frequency-domain small-signal modeling of a three-phase four-wire shunt Active Power Filter

Current harmonics, which are injected in the utility by nonlinear loads, cause major problems that tend to deteriorate the power quality at the mains. To reduce such harmonics, active power filters (APF) are commonly employed. Challenges in improving the performance of such systems by designing sophisticated control algorithms occupy actually a major field of interest for power electronics researchers. In this paper, a new frequency-domain small- signal model of a shunt three-phase four-wire APF is presented for linear control purpose. The model calculation is based on a state-space averaged model of the filter, computed in the (d,q,0) synchronous frame. The obtained transfer functions offer new simple, systematic and straightforward alternatives for the design of linear control schemes that would ensure suitable performance for the filters.