Electrical power generation through concentrated solar technology for the southern cities of Iraq

With a continuing mismatch between generating capacity and demand requirements, Iraqi cities are still enduring scheduled power outages. In this work, concentrated solar power (CSP) technology is proposed and designed for Iraqi cities to inject power into distribution networks with the objective of boosting the generating power capacity. Since CSP systems require a preliminary study of the direct normal irradiance (DNI), analyses of monthly data is carried out for each of the candidate cities. This is followed by determination of the amount of solar irradiance that falls on a titled collector per month considering the effects of reflection and diffusion. Finally, a thermal power plant is proposed and simulated using the system advisory model (SAM) per city. Results presented show an encouraging number of metrics and confirm the feasibility of such a plant in southern Iraq. The levelised cost of electricity and capacity factor shows a considerable decrease and increase respectively, when the plant is backed up by a fossil fuel steam cycle under circumstances when a plant loses over 80% of the MW capacity due to drop in solar irradiance. To provide a comparision platform, for each city, a photovolitaic (PV) plant is designed with an indentical electric capacity to that of the CSP plant. Findings from this work confirm that CSP plants can provide a suitstanable and enviroemntl friendly solution to electrical power shortages in the country compared to the current PV trends

A secure image steganography based on burrows wheeler transform and dynamic bit embedding

In modern public communication networks, digital data is massively transmitted through the internet with a high risk of data piracy. Steganography is a technique used to transmit data without arousing suspicion of secret data existence.  In this paper, a color image steganography technique is proposed in spatial domain. The cover image is segmented into non-overlapping blocks which are scattered among image size window using Burrows Wheeler transform before embedding. Secret data is embedded in each block according to its sequence in the Burrows Wheeler transform output. The hiding method is an operation of an exclusive-or between a virtual bit which is generated from the most significant bit and the least significant bits of the cover pixel. Results of the algorithm are analyzed according to its degradation of the output image and embedding capacity. The results are also compared with other existing methods

Capacitor current analysis of a three-level neutral point clamped converter under unbalanced loading conditions

A neutral point clamped (NPC) converter is considered a forefront in industrial applications. Supplying a typically balanced stand-alone load is one of those applications. However, the loading may become unbalanced which can impact the capacitors’ current and voltage ripple. In this work, an approach is proposed that analyze the capacitor current under unbalanced loading. The proposed method is based on a combination of two-dimensional Fourier series and symmetrical components. Since, two-dimensional Fourier series sectorize the spectrum into harmonics that are either defined by multiples of, fundamental, carrier or both frequencies, the method derives the Fourier coefficients for each sector, corresponding to a sequence current. Therefore, based on the presented approach, each harmonic amplitude in the spectrum sector is defined by three Fourier coefficients reflecting zero, positive and negative sequence current. The capacitor current spectrum is obtained by vector summing sequence coefficients. The method is tested on unbalanced load conditions with (out) a ground path. Results verify feasibility of the proposed method in deriving Fourier coefficients of capacitor currents that accurately reflects the loading status of the NPC. This is vital for converter design in terms of proper sizing of DC capacitor and can help in avoiding components failure

Analysis of Five Level Neutral Point Clamped Inverter Fed from 18 Pulse ‎Output Multiphase Rectifier for Grid Tied Applications

 تلعب محولات إلكترونيات الطاقة دورًا رئيسيًا في تطبيقات معالجة الطاقة المختلفة. في كثير من الحالات ، تنشأ الحاجة إلى استخدام محولين لتحقيق معالجة الطاقة أو التكييف أو كليهما. في هذا العمل ، تمت دراسة نظام محولين يعتمد على محولين متعدد الأطوار / متعدد المستويات. الهدف الرئيسي هو معالجة طاقة التيار المتناوب من مصدر يمكن أن يكون مصدر طاقة موزع (DER) عن طريق تحويله إلى تيار مستمر قبل حقنه في نظام تيار متردد آخر. يتم استخدام مقوم متعدد الأطوار ذو 18 نبضة للهدف الأول. يتم تحقيق مهمة المعالجة الثانية ، والتي تتضمن تحويل طاقة التيار المستمر إلى التيار المتناوب من خلال محول محايد ذو خمسة مستويات مثبتة .(NPC)  النتائج المبينة تحقق فوائد المعدل متعدد الأطوار في إنتاج جهد تيار مستمر سلس. ومن جانب أخر ، تتميز NPC ذات المستويات الخمسة بميزة مثيرة للاهتمام وهي ان الجهد الأساسي ذو قيمة عالية.Power electronics converters play a major role in various energy processing applications. In many instances the need arises to use two converters to achieve power processing, conditioning or both. In this work, two converter systems are studied, which is based on two multiphase/multilevel converters. The main objective is to process AC power from a source which can be a distributed energy source (DER) by converting it to DC before injecting it into another AC system. An 18 pulse multiphase rectifier is used for the first objective. The second processing task, which involves converting the DC power back to AC is achieved by five level neutral point clamped converter (NPC). Results verify the benefits of the multiphase rectifier in producing a smooth DC voltage. On the other side, the five level NPC revels an interesting feature of high fundamental voltage