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Power quality problems such as voltage sag, voltage swell, voltage transients, voltage interruptions, and harmonics are becoming significant issues throughout the world. It has been seen that power quality problems resulted in the loss of more than 22 billion dollars in one year in industries of US and more than 500 consumers received a loss in the shape of damage or failure of equipments in 1991. A commonly occurring power quality problem in the electrical power distribution network is voltage sag which makes the sensitive loads of the network at risk. Static Synchronous Compensators, Distribution Series Capacitors and Power Factor Corrector, Static VAR Compensator, Uninterruptable Power Supply, and Solid-state Transfer Switches were used for stabilization but we are facing problems such as difficult maintenance, high cost of services and require large space. So valuable solution to mitigate the problem of voltage sag is the DVR. It is a series DVR. DVR is the series connected device which added the voltage to the load when needed. The most important component of a DVR is the Voltage Source Inverter; through this, we can provide the needful controllable voltage for compensation but it required energy storage device which results in high cost. The Matrix Converter has better performance as compared to other inverters due to direct conversion from AC to AC voltage and there is no need of energy storage unit which results in reduced cost and operational complexity. The control circuit is very essential for DVR; it retains a constant voltage and its magnitude at the load point. DVR is non-linear device due to presence of converter circuit, so for satisfactory performance of DVR, non-linear controller is essential. In this review paper, different topologies of DVR are discussed and performances of a DVR is analyzed under open loop system and also control strategy of PID controller through MATLAB simulation software.

The integration of wind turbine, solar photovoltaic based distributed generation in low voltage distribution network has many advantages. However, the output power from wind turbine and solar PVs are intermittent in nature. The production of these intermittent power generations may introduce many challenges in distribution network such as increase in power losses, voltage deviation and instability. Therefore, this paper proposes optimal integration of these intermittent renewable DGs along with biomass and capacitor banks to optimize distribution network parameters. The real time wind speed and solar irradiance data are processed in time series mathematical model along with relevant probability distribution function (PDF) for calculating the accurate power output from these renewable resources. Later, an advanced multi-objective particle swarm optimization technique has been used to optimize the distribution network parameters such as power losses, voltage deviation and voltage stability index. The proposed model has been validates and tested on Portuguese 94 bus system. Moreover, the proposed model results revealed the power loss reduction up to 77.82%, voltage deviation 9.68% and voltage stability index 44.25%.

The increasing environmental awareness across the globe is leading towards a green and clean world. Currently, Pakistan is going through an acute energy crisis; it is an on-going challenge for the government to provide uninterrupted power supply at economical rates to its citizens and potential industrial investors, now and in future. Thus, this energy scenario necessitates the incorporation of renewable energy technologies with power systems to enhance its generation capacity, and to overcome electricity outage of approximately 8-12 hours, in the country. In this paper, the authors encouraged the state policy for utilizing the wind energy for power generation, which is freely available across 1600 km long coastal belt of Pakistan. For this purpose, wind potential is explicitly evaluated across Sindh and Baluchistan provinces in Pakistan. The energy generated by various wind turbine prototypes is employed to suggest the most optimum location through optimal probability function. Moreover, this study provides an evocative progression based on real-time wind data to integrate wind power for rural electrification across the coastal zones of Pakistan. This study is expected to play an imperative role in incorporating wind farms on proposed sites to facilitate investors interested in investing in Pakista's energy sector.

The escalating energy demand across the globe has intensified the electricity production. Owing to the unavailability of the reliable techniques for electricity storage for a long duration, it is consumed immediately after its production. Therefore, electricity markets can’t be handled like the conventional stock markets. Power companies are facing immense price and delivery risks owing to the increasing competition in the electricity markets. As a result, risk management is the fundamental concern to be addressed in order to achieve the optimum profit targets. Consequently, the power generation organizations need to allocate their generation in bilateral contracts and spot market. For this purpose, an optimal theory of portfolio selection is proposed in this study for electricity generation by forming a reliable prototype and applying the proposed scheme to obtain the suitable outcomes. The Paris Accord on environmental safety from carbon dioxide and NOx gases is especially considered during the modeling of the proposed technique. The credibility of the proposed scheme is validated by using the real-time market data from the PJM market. Various risk-return tradeoffs are implemented, and their corresponding solutions are acquired for portfolio optimization as corroborated by the results. The suggested technique is found reliable and adequate for the carbon tax paying suppliers around the world for allocating their respective generation based on the demand of the consumers.

Power outage owing to shortage of power generation, transmission losses, lack of planning and inappropriate policies has led to escalate the energy crisis in Pakistan. The reason for selecting Pakistan is to facilitate its 220 million population and to attract the international investors to take benefit by integrating power generation units into National Grid of Pakistan (NGOP). Domestic, Industrial, health and education sectors are badly affected due to this power crisis. Instead of remedial measures and providing incentives to the investors in power sector, the government of Pakistan (GOP) has remained unable to overcome the dilemma in power sector due to improper check and balance. The failures in completion of hydropower dams and generating electricity by fossil fuels has resulted in increased power generation cost and environmental hazards. Therefore, some suitable solutions are compulsory for meeting the escalating power demands adequately. The incorporation of renewable energy units and stopping electricity theft can be the most explicit choice for meeting aforementioned problems. This paper explores the vast potential of Pakistan with respect to energy production by means of solar and wind power units. Moreover, most appropriate sites for incorporating power generation units are also critically reviewed. The paper also proposes the short-term, mid-term and long-term effective solutions along various practical proposals for overcoming the existing power crisis in Pakistan. Keywords: Power outage, HVDC, Energy crisis, Energy solutions, Renewable energy, Pakistan

In the last few decades, wind energy has become a significant source of the renewable energy system, and it is essential to use wind energy for generating power and run the wind turbine system (WTs) at a higher level. With the rapid penetration of wind energy in the distributed generation system (DGS) and isolated micro-grid (MG), the WT runs at its optimal energy conversion output. For this, WT has to track or drive at the optimal power point tracking algorithm. However, various publications are available on MPPT algorithms for wind energy system (WES) applications, making a choice on exact trackers for a particular algorithm because each tracker has its advantages and disadvantages. Therefore, our primary goal is to review and evaluate the exact tracking algorithm for WES applications in this manuscript. To introduce the power controller, it is essential to track maximum power despite wind energy results. Besides, many algorithms have been evaluated, and their maximum output is achieved compared to their performance. This research paper will help researchers provide an accurate reference for future recommendations by selecting the best tracking algorithms in WES.

This paper primarily focuses on an advance control strategy to enhance the low voltage ride through (LVRT) capability in doubly fed induction generator (DFIG) based wind energy conversion system (WCES). In the proposed control strategy, the captured wind energy during grid faults circumstances is stored timidly in the rotor&rsquo, s inertia kinetic energy. Though a minimal amount of energy is available in the grid, stator current and DC-link voltage are set beneath the perilous levels. However, both the required stator voltage and stator current are kept within a tolerable range of rotor side converter (RSC), through state feedback linearization technique for maintaining the accurate control to suppress the overvoltage and overcurrent. Furthermore, stator current oscillations are significantly suppressed during fault transient. The input mechanical energy from the wind turbine can be resumed after the fault clearance. In spite of being dissipated in the resistors of crowbar circuit, as in the conventional LVRT assemblies, torque balancing among electrical and mechanical measures is attained, DC-link voltage instabilities and rotor speed inconsistencies are substantially reduced. As a result, a noticeable reduction in the requirement of reactive power and swift restoration of terminal voltage on fault clearance is acquired successfully. Correspondingly, several tests are conducted to validate the effectiveness and enhancement in the performance of the DFIG based wind farms, when the proposed control strategy is implemented over it during numerous fault ride-through circumstances.

This paper presents a dynamic modeling and control of doubly fed induction-generator (DFIG) based on the wind turbine systems. Active and reactive power control of the DFIG are based on the feedback technique by using the suitable voltage vectors on the rotor side. The rotor flux has no impact on the changes of the stator active and reactive power. The proposed controller is based on the feedback technique in order to reduce the oscillation of the generator. The control approach is estimated through the simulation result of the feedback controller assembled with DFIG wind turbines. It is applied by the feedback control based techniques in order to control the power flowing of DFIG and the power grid. Hence, an improved feedback control technique is adopted to get a better power flow transfer and to improve the dynamic system and transient stability. In stable condition, the improved performance of the controller, the proposed method is verified for the effectiveness of the control method is done in stable conditions.

This paper presents a dynamic modeling and control of doubly fed induction-generator (DFIG) based variable speed wind-turbine. The dynamic model of DFIG is incorporated with all system components which provide simple design and controls. The penetration of wind power is increasing into electrical networks, which necessitates more comprehensive studies to recognize the interaction between the wind farms and the power grid. This paper presents the dynamic model of a DFIG based wind turbine connected to the grid system in the dq-synchronous reference frame. In this article, the feedback linearization method has proposed a controller in order to reduce the oscillation and stabilize the wind turbine system parameters based on feedback linearization concepts. Based on the nonlinear control system, the proposed approach is applied to the rotor side converter and grid side converter. The damping of the DFIG is improved in transient response. In addition, the oscillation of the stator current and DC link voltage during the generator voltage dip are reduced. To the best of author’s knowledge, the proposed control outcomes compared with conventional controller verified the effectiveness, having better performance through simulation tool Matlab.

In the recent years, globally wind energy has played a vital role in renewable sources in order to minimize the environmental consequence on power generation, As a result of this, computer models of wind turbines for power system stability studies have been developed and supplied to the consumer. Therefore, the development of such models is of particular consequence for stability of power system, which has been studied and can be structured and integrated into network simulation software are needed. However, in this contribution a nonlinear control design modeling is required to stabilize and analyze wind energy conversion system (WECS) by regulating the electrical frequency and stator voltage amplitude of the squirrel-cage induction generator (SCIG) at random wind speed approach is presented. A design scheme consists of dynamic wind turbine system and 3-phase SCIG unit. In this research study, we employ a unique technique based on feedback linearization technique through field oriented control concepts. The controllers were designed in simulated software Matlab in order to regulate the SCIG constraints. The validation of the developing system models will be appropriate to provide for large system stability and control.

The energy is the serious issue, directly or indirectly, in the whole practice of advancement, development and existence of all the existing creatures. It plays a very important part in socioeconomic growth and social prosperity of any country, at least 1/3rd of the country has no access of energy like electricity. Globally Pakistan is an electricity lacking country, however deficient in oil and gas. Pakistan is rich in sources like water, coal, wind and solar energy. Electricity is the basic needs of all human’s comfort and in addition to overcome power crises in common, Pakistan desires in the way to utilize its natural power assets similar to hydel power plant, sunlight and wind potential for the generation of electricity. Pakistan has surely considerable latent for exploiting wind energy. Additionally about 1000 km lengthy shoreline in southern and northern hilly areas offers an outstanding reserve of wind potential. The efforts need for utilization of wind energy in the country. This study includes only twenty selected regions of southern regions of Sindh province for power generation from a natural source of wind energy.

In this manuscript, a hybrid wind/solar/battery energy system is proposed for a stand-alone applications. Wind-solar energy sources are used as power generation source in the proposed hybrid energy system (HES), whereas battery is used as energy storing system in order to manage the power flow among various power generation sources and energy storing system. Power management control strategy is also presented for a suggested hybrid system. Through the real load demand and practical weather data (proposed area is Jamshoro, Sindh Pakistan), the system performance is verified under different situations. It is observed that the hybrid system produces maximum power in summer season as compared to other seasons throughout the year. Moreover, the power generated from wind and solar energy contributes 77.88% and 22.12%, respectively. However, it is clearly observed that the HES is cost effective and can be used in remotely rural areas which are isolated from power grid. In future work, the HES can be integrated with the power grid in order to meet the load demand during shortage of power.

The non-renewable energy resources are limited and depleting gradually. As such, energy security has attained the greatest amount of attention globally than ever before. In the meantime, energy crises are already affecting the developing countries such as Pakistan, even though one-third of the population of the country is not even not connected to the national electricity grid. The population with access to on-grid electricity is enduring load shedding of more than 12 h a day. This situation is alarming and require immediate attention is required so as to add alternative energy resources to the country, which has long been relying on imported fuels. It is, therefore, high time that the abundant potential in the renewable energy resources of Pakistan such as solar, wind, and biomass are harnessed. These renewable energy resources are economical and environmentally friendly, and thus considered as sustainable, and the utilization of these in meeting energy demands can help to conserve conventional resources early diminishing. This paper provides a detailed description of the energy consumption and load-shedding scenario in Pakistan thereby focusing specifically Sindh and Baluchistan provinces. Since, wind energy is considered one of the cost-effective renewable resources, six potential sites in these two provinces are considered in this study. These sites lie within 250 km of the southeastern and 800 km of the southwestern regions of Pakistan. One-year wind speed data have been reported for variable heights of these proposed sites which represent to have an annual average wind speed of 6.63 m/s and 5.33 m/s respectively. The power generation data for these location of two provinces is 7.653 GWh, and 5.456 GWh per annum respectively. This study also elaborates on the advantages and disadvantages of harvesting and installing the wind energy and provides a technical proposal for the generation of electricity from the wind in the selected remote zones which are off the national grid. The findings of this paper will help concerned government departments to devise appropriate policies and attract investment in the wind energy sector to eradicate the on-going electricity crisis.

In the modern era, distributed generation is considered as an alternative source for power generation. Especially, need of the time is to provide the three-phase loads with smooth sinusoidal voltages having fixed frequency and amplitude. A common solution is the integration of power electronics converters in the systems for connecting distributed generation systems to the stand-alone loads. Thus, the presence of suitable control techniques, in the power electronic converters, for robust stability, abrupt response, optimal tracking ability and error eradication are inevitable. A comprehensive review based on design, analysis, validation of the most suitable digital control techniques and the options available for the researchers for improving the power quality is presented in this paper with their pros and cons. Comparisons based on the cost, schemes, performance, modulation techniques and coordinates system are also presented. Finally, the paper describes the performance evaluation of the control schemes on a voltage source inverter (VSI) and proposes the different aspects to be considered for selecting a power electronics inverter topology, reference frames, filters, as well as control strategy.

Unfortunately, Pakistan is facing an acute energy crisis since the past decade due to the increasing population growth and is heavily dependent on imports of fossil fuels. The shortage of the electricity is 14-18 hours in rural areas and 8-10 hours in urban areas. This situation has been significantly affecting the residential, industrial and commercial sectors in the country. At this time, it is immense challenges for the government to keep the power supply provision continue in the future for the country. In this situation, it has been the increased research to explore renewable energy resources in the country to fulfill the deficit scenario in the state. The renewable energy sector has not penetrated in the energy mix, currently in the upcoming markets. This paper highlights the steps taken by the country in the past and is taking steps at the present time to get rid of from the existing energy crisis when most urban areas are suffering from power outages for 12 hours on regular basis. Until 2009, no single grid interconnected wind established, but now the circumstances are changing significantly and wind farms are contributing to the national grid is the reality now. The initiation of the three wind farms interconnection network and many others in the pipeline are going to be operational soon. The federal policy on wind energy system has recently changed. Surprisingly, the continuing schemes of the wind farm are getting slow. This paper reviews developments in the wind energy sector in the country and lists some suggestions that can contribute to improving the penetration of wind energy in the national energy sector.Keywords: Wind energy, evolution of wind resource, Wind sites of PakistanArticle History: Received Dec 16th 2016; Received in revised form May 15th 2017; Accepted June 18th 2017; Available onlineHow to Cite This Article: Kaloi,G.S., Wang, J., Baloch, M.H and Tahir, S. (2017) Wind Energy Potential at Badin and Pasni Costal Line Pakistan. Int. Journal of Renewable Energy Development, 6(2), 103-110.https://doi.org/10.14710/ijred.6.2.103-110

The present paper formulates the state space modeling of doubly fed induction generator (DFIG) based wind turbine system for the purpose of the stability analysis. The objective of this study is to discuss the various modes of operation of the DFIG system under different operating conditions such as voltage sags with reference to variable wind speed and grid connection. The proposed control methodology exploits the potential of the DFIG scheme to avoid that grid voltage unbalances compromise the machine operation, and to compensate voltage unbalances at the point of common coupling (PCC), preventing adverse effects on loads connected next to the PCC. This methodology uses the rotor side converter (RSC) to control the stator current injected through the machine and the GSC to control the stator voltage to minimize the electromagnetic torque oscillations. Extensive simulation results on a 2MW DFIG wind turbine system illustrate the enhanced system performance and verify the effectiveness of the controller.