Power Quality Consideration for Off-Grid Renewable Energy Systems

Necessity of electricity access in remote area is the main reason for expanding decentralized energy system such as stand-alone power systems. The best electrical power supply must provide a constant magnitude and frequency voltage. Therefore, good power quality is an important factor for the reliable operation of electrical loads in a power system. However, the current drawn by most of electronic devices and non-linear loads are non-sinusoidal, which can result in a poor power quality, especially in off-grid power systems. Poor power quality is characterized by electrical disturbances such as transients, sags, swells, harmonics and even interruptions in the power supply. Off-grid power systems world- wide often struggle with system failures and equipment damage due to poor power quality. In this paper, MAT- LAB/Simulink is used to model and analyses power quality in an off-grid renewable energy system. The results show high voltage transient when the inductive loads were switched OFF. The voltage and current harmonics are also deter- mined and compared for various types of loads

Mathematical modeling for SnO2 gas sensor based on second-order response

Sensors, work on the entrance gate for exploring dynamic environments and system response. The sensor behavior plays an important role in system modeling. Therefore, finding the mathematical model, which can describe the sensor response with maximum information over time in different environments and situations, is necessary. This paper, attempts to model the optimal transfer function of the SnO2 type gas sensor (TGS 813) for transient response and steady-state zones, based on the acquired data of the sensor. The model could be used to obtain the mathematical equation for the response, as a transfer function based on different concentrations, for the specific temperature and humidly. The data analysis has been done with Matlab software, and Genetic algorithm is further used to optimize the transfer function parameters. Moreover, the effect of variation in concentration on the transfer function coefficients has been explored. The results show that the modeling can be helpful for sensor response behavior simulation as well as physical and chemical reaction investigation

The energy and cost calculation for a Marx pulse generator based on input dc voltage, capacitor values and number of stages

Visualization of the energy equation can simplify understanding the performance of a Marx pulse generator. In this paper, the energy of a Marx pulse generator is calculated and visualized for input dc voltage from 1 to 20 kV, value of the capacitor from 1 to 33 nF and the number of stages from 1 to 20 stages. Moreover, in order to calculate the approximate cost of the Marx pulse generator, an equation proposed and evaluated

Optimal power demand curve: a case study in Universiti Putra Malaysia

The necessitation in the optimal power demand model, make it an impetus to present this work as a glaring path in determining the optimum power demand curve, using the available data of a substation. The data are used to find the equation and its coefficients of determination that can give the best-fit curve of the power demand of a substation, based on the available data. This will produce a model that can be validated by comparing the data and figured out the equation

Ambient temperature effect on Amorphous Silicon (A-Si) Photovoltaic module using sensing technology

Temperature and solar irradiance are the two dominating cardinals that determine the electrical performance of Photovoltaic (PV) module. In this paper, an experiment is conducted considering Amorphous Silicon (A-Si) PV module in both indoor and outdoor condition to investigate the temperature effect on A-Si module's performance in terms of efficiency and output power through an automatic resistor selection system. The experimental result shows that A-Si PV module has small temperature coefficient effect; however it has higher effect on solar radiation coefficient. A comparison analysis is evaluated with different models to validate the experimental data

Variable high frequency voltage source for an ohmic heating process

Heating is an important step in food processing. A new method of heating uses the natural electrical resistance of the food to generate heat. In this method electrical energy is transformed into thermal energy. This kind of food heating processing operation is called ohmic heating. The rate of ohmic heating critically depends on the Electrical Conductivity of the food during the process. Reviewing a number of researches shows that the usage of direct current for ohmic heating process causes electrolyze in liquid beverages. Moreover, usage of alternating current eliminates the probability of adverse electrochemical reaction. In addition, when the frequency increases, the risk of oxidation in electrodes will decrease. In this regard, for heating different kinds and sizes of food, it is necessary to have an electrical power source with variable output voltage and frequency. This research attempts to design and simulate the variable voltage and frequency electrical power source to feed a 10 kW ohmic heating process at high frequency (10 kHz). The ohmic heating load is simulated by three-phase resistive load. According to Joulepsilas first law, the temperature in heat generation process is closely related to electrical power and time of process. Hence, in this simulation, the value of temperature is controlled by value of power that is generated by current which flows through resistive load with control of the time period and the duty cycle. Furthermore, one of the most important things to have an effective ohmic heating process is supplying the continuous current during the process. The result of this study indicated a simple method to supply a continual current for load during the ohmic heating process

CO2 gas sensing properties of screen printed La2O3/SnO2 thick film

The present investigation deals with the fabrication of CO2 gas sensor based on La2O3/SnO2 metal-oxide material. In this paper, the sensitive material was prepared by La2O3/SnO2 nanopowder and the addition of 1 wt. % and 3 wt. % platinum (Pt) using high-speed ball milling method. The sensitive film prepared by sensitive powder was printed on alumina (Al2O3) substrate by screen printing method. This film was characterized by X-Ray powder diffraction spectroscopy, and Field-emission scanning electron microscopy. As a result, the prepared 3 wt. % Pt/La2O3/SnO2 thick film sensitive paste exhibits a high sensitivity to increasing the CO2 gas concentration at 225 °C in air atmosphere

A new mathematical model for mapping indoor environment

This paper presents a mathematical model as a new approach to object mapping, the system is proscribed to indoor and applied to approach a landmark. The contribution of this paper is to propose a new mathematical model for object mapping, the landmark is captured at varying distant points, the Scale invariant Feature Transform (SIFT) to extract object options, at the side of their uncertainty, from camera sensors. The (SIFT) features are invariant to image scaling, translation, and rotation, and partially invariant to illumination changes and affine or 3D projection, which is suitable for our application. As image options do not seem to be noise-free, the error analysis of the landmark positions and a preprocessing to obtained information which is incorporated into a model, using curve fitting techniques. Predictions createdby our model square measure well and correlate with experimental knowledge. This has eliminated correspondence Problem also known as a data association problem

Innovating problem solving in power quality devices: a survey based on Dynamic Voltage Restorer case (DVR)

The theory of inventive problem solving (TRIZ) is one of emerging creative problem solving methodologies. This paper proposes a way to simplify TRIZ for electrical domain usage, while making it feel less complex, more relevant and understand able for users in a specific sector. This research takes Dynamic Voltage Restorer (DVR) device as a case from electrical engineering domain, to demonstrate the proposed TRIZ based guidance framework development which will assist in solving problems of DVR devices. The proposed sector specific guidelines in particular segment of Electrical Engineering (e.g. power quality device DVR) will be closer, more comprehensible and particularly linked to key parameters of that sector. By using the derived guidance framework, field engineers with very basic TRIZ knowledge may apply TRIZ confidently for design and problem solving purpose

Probing potential of knowledge engineering support for electrical engineers – a case study

Because of ever increasing complexity of electrical engineering systems, this is needed to provide supportive guidance to electrical engineers in dealing with increasing complexity of systems. This paper summarizes a case study conducted to assess qualitative benefits of emerging knowledge engineering tool named TRIZ (Theory of inventive problem solving), for the field of electrical engineering. The study considers few key aspects, which proves that knowledge based guidance can facilitate electrical engineers at initial stages of solution hunting and design process. This early conceptual guidance results into reaching more practical innovative solutions with less time and less need of very high expertise in multiple fields. For purpose of this case study, a group of electrical engineers from National Engineering Consultants (NEC) Pakistan were consulted. Engineers involved in discussion presented few common problems which they faced in their field of working. Initial stages TRIZ based conceptual guidance for reaching innovative and practical solutions was explored and feedback of this joint session is summarized in this paper