Wajahat Tareen - Academia.edu (original) (raw)
Papers by Wajahat Tareen
Mathematical Problems in Engineering, 2022
Many underdeveloped countries are facing acute shortage of electric power and short term measures... more Many underdeveloped countries are facing acute shortage of electric power and short term measures are important to consider to address the problems of power outage, power plant failures, and disaster areas. Distributed generation (DG) is a promising approach for such cases as it allows quick on-site installation and generation of electric power. Injection of DG can improve the system voltage profile and also reduce the system's total power losses. However, the placement and sizing of the DG unit is an optimization problem in the radial distribution system. As a test case, this study examines voltage profile improvement and system power losses for an 11 KV residential feeder at the Abdul Rehman Baba grid station in Pakistan, which is modelled using the Electrical Transient Analyzer Program (ETAP). For various scenarios, several tests are conducted to assess the effects of DG on the distribution system. The results show that proper design considerations of size and location of a D...
Electronics
In this article, a compact four-port MIMO antenna system resonating from 4.7–5.1 GHz on −6 dB cri... more In this article, a compact four-port MIMO antenna system resonating from 4.7–5.1 GHz on −6 dB criteria is discussed. The proposed antennas are arranged in a perpendicular manner providing diversity with good isolation characteristics. The proposed antenna was fabricated and designed on a commercially available low-cost FR-4 substrate with a relative permittivity of 4.4. The total size of the antenna is 40 × 40 mm2, and a minimum isolation of 25 dB was observed at most nearby resonating elements. The proposed antenna was fabricated and tested at an in-house facility, and the measured results agree well with the simulations. The MIMO antenna characteristics, such as the envelope correlation coefficient (ECC) among any two radiating elements, have been found to be less than 0.1, and the diversity gain (DG) value evaluated showed that the proposed antenna is well designed. Furthermore, the SAR analysis showed that the desired antenna system is safe for users, with a value of 0.94 W/Kg. ...
2017 IEEE Applied Power Electronics Conference and Exposition (APEC), 2017
In order to reduce the system cost, volumetric size and weight of an electric vehicles (EVs) batt... more In order to reduce the system cost, volumetric size and weight of an electric vehicles (EVs) battery charger, a novel four-switch two-leg VSI configuration is propose for rapid battery charging with the active power filter (APF) features. It consists of cost-effective two-arm bridge converter, coupling inductors, LC filters, buck converter and EV battery. Note that the conventional three-leg bridge structure is reduce to two-leg VSI structure, functioning like three-phase rectifier to converts power from ac-dc during the battery charging process. The third-leg and set of power switching devices are eliminate by directly connecting the grid phase with the negative terminals of dc-link capacitor. Therefore, third leg of the EV charger is use as a buck converter for battery charging. The charger controller ensures the rapid charging capabilities in constant current and constant voltage (CC-CV) modes, with additional functions of harmonic compensation capability, power factor correction...
Energies
This paper investigates the impact of tube wells on the discharge and water table of the Quetta V... more This paper investigates the impact of tube wells on the discharge and water table of the Quetta Valley aquifer and conducts a financial analysis of the solar photovoltaic water pumping system (SPVWP) in comparison with a typical pumping system for the Water and Sanitation Agency of Quetta’s (WASA) tube wells. Quetta Valley is dependent on groundwater as surface resources are on decline and unpredictable. The population of this city has exponentially increased from 0.26 million in 1975 to 2.2 million in 2017 which has put a lot of pressure on the groundwater aquifer by installing more than 500 large capacity tube wells by WASA and Public Health Engineering (PHE) departments in addition to thousands of low-capacity private tube wells. The unprecedented running of these wells has resulted in drying of the historical Karez system, agricultural activities, and the sharp increase in power tariffs. There are 423 tube wells in operation installed by WASA in addition to PHE, Irrigation and M...
Energies
Electric vehicles’ (EVs) technology is currently emerging as an alternative of traditional Intern... more Electric vehicles’ (EVs) technology is currently emerging as an alternative of traditional Internal Combustion Engine (ICE) vehicles. EVs have been treated as an efficient way for decreasing the production of harmful greenhouse gasses and saving the depleting natural oil reserve. The modern power system tends to be more sustainable with the support of electric vehicles (EVs). However, there have been serious concerns about the network’s safe and reliable operation due to the increasing penetration of EVs into the electric grid. Random or uncoordinated charging activities cause performance degradations and overloading of the network asset. This paper proposes an Optimal Charging Starting Time (OCST)-based coordinated charging algorithm for unplanned EVs’ arrival in a low voltage residential distribution network to minimize the network power losses. A time-of-use (ToU) tariff scheme is used to make the charging course more cost effective. The concept of OCST takes the departure time o...
Sustainability
This study summarizes a critical review on EVs’ optimal charging and scheduling under dynamic pri... more This study summarizes a critical review on EVs’ optimal charging and scheduling under dynamic pricing schemes. A detailed comparison of these schemes, namely, Real Time Pricing (RTP), Time of Use (ToU), Critical Peak Pricing (CPP), and Peak Time Rebates (PTR), is presented. Globally, the intention is to reduce the carbon emissions (CO2) has motivated the extensive practice of Electric Vehicles (EVs). The uncoordinated charging and uncontrolled integration however of EVs to the distribution network deteriorates the system performance in terms of power quality issues. Therefore, the EVs’ charging activity can be coordinated by dynamic electricity pricing, which can influence the charging activities of the EVs customers by offering flexible pricing at different demands. Recently, with developments in technology and control schemes, the RTP scheme offers more promise compared to the other types of tariff because of the greater flexibility for EVs’ customers to adjust their demands. It h...
Sustainability
The uncoordinated integration of electric vehicles (EVs) severely deteriorates the operational pe... more The uncoordinated integration of electric vehicles (EVs) severely deteriorates the operational performance of a distribution network. To optimize distribution network performance in an EV charging environment, this paper presents a two-stage optimization approach, which integrates coordinated EV charging with network reconfiguration. A formulation to minimize system power loss is presented, and an optimal solution is obtained using a binary particle swarm optimization algorithm. The proposed approach is tested on a modified IEEE 33-bus medium-voltage node test system, coupled with a low voltage distribution network. Results of the coordinated and uncoordinated EV charging are compared with those of the developed integrated approach, and the operational performance of the system is studied. The results show that the integration of network reconfiguration with coordinated EV charging significantly decreases network power losses and fairly improves voltage profile. Thus, the proposed s...
Sustainability
Pakistan is a developing country that is experiencing a shortage of electricity generation due to... more Pakistan is a developing country that is experiencing a shortage of electricity generation due to its rapidly growing demand. The existing and upcoming energy requirements for power generation and future transportation can be met by efficient utilisation of homegrown biomass resources. Determining the present energy mix resources in various sectors of the country is important. This article analyses the biomass resources and their potential and bioenergy utilisation in Pakistan. An overview of the global renewable energy scenario is presented. This article accentuates the importance and challenges of new technologies and estimates the current and future share of power generation from renewable sources, focusing on the technical potential of biomass energy, which is obtained from agricultural residues, animal manure and municipal solid wastes in Pakistan. This paper highlights the developing technologies that are primarily used to convert biomass waste into energy and presents a criti...
Energies
Pakistan is experiencing an undersupply of electricity, causing load shedding several hours per d... more Pakistan is experiencing an undersupply of electricity, causing load shedding several hours per day due to the adherence to conventional energy resources having quantitative and environmental limitations. Fossil fuels generate more than half of the country’s total electricity, but they will ultimately run out due to their limited supply. Their combustion emits greenhouse gases, posing environmental threats. Since the world is tending toward efficient and sustainable alternative methods for harvesting energy from nature, Pakistan has also been investigating an elevated deployment of renewable energy projects. This paper presents a critical analysis of the present energy sector of Pakistan along with global scenarios. Pakistan relies on mainly thermal, hydro, and nuclear energy for power generation. National solar, wind, geothermal, and biomass resources have not been extensively explored and implemented. This paper provides an insight into the potential of these resources in Pakistan...
IEEE Transactions on Power Electronics
Energies, 2017
Uninterruptible power supplies (UPSs) are widely used to deliver reliable and high quality power ... more Uninterruptible power supplies (UPSs) are widely used to deliver reliable and high quality power to critical loads under all grid conditions. This paper proposes a high-frequency isolated online UPS system for low power applications. The proposed UPS consists of a single-stage AC-DC converter, boost DC-DC converter, and an inverter. The single-stage AC-DC converter provides galvanic isolation, input power factor correction, and continuous conduction of both input and output current. The low battery bank voltage is stepped up to high dc-link voltage by employing a high voltage gain boost converter, thus allows the reduction of battery bank to only 24 V parallel connected batteries. Operating batteries in parallel improves the battery performance and resolves the issues related to conventional battery banks that arrange the batteries in series combination. The inverter provides regulated output voltage to the load. A new cascaded slide mode (SM) and proportional-resonant (PR) control for the inverter has been proposed, which regulates the output voltage for both linear and non-linear loads. The controller shows excellent performance during load transients and step changes. Besides, the controller for boost converter and AC-DC converter is presented. Operating principle and experimental results of 1 kVA laboratory setup have been presented for the validation of proposed system.
Energies, Jun 7, 2018
This study summarizes an analytical review on the comparison of three-phase static compensator (S... more This study summarizes an analytical review on the comparison of three-phase static compensator (STATCOM) and active power filter (APF) inverter topologies and their control schemes using industrial standards and advanced high-power configurations. Transformerless and reduced switch count topologies are the leading technologies in power electronics that aim to reduce system cost and offer the additional benefits of small volumetric size, lightweight and compact structure, and high reliability. A detailed comparison of the topologies, control strategies and implementation structures of grid-connected high-power converters is presented. However, reducing the number of power semiconductor devices, sensors, and control circuits requires complex control strategies. This study focuses on different topological devices, namely, passive filters, shunt and hybrid filters, and STATCOMs, which are typically used for power quality improvement. Additionally, appropriate control schemes, such as sinusoidal pulse width modulation (SPWM) and space vector PWM techniques, are selected. According to recent developments in shunt APF/STATCOM inverters, simulation and experimental results prove the effectiveness of APF/STATCOM systems for harmonic mitigation based on the defined limit in IEEE-519.
Renewable and Sustainable Energy Reviews, 2017
Mathematical Problems in Engineering, 2022
Many underdeveloped countries are facing acute shortage of electric power and short term measures... more Many underdeveloped countries are facing acute shortage of electric power and short term measures are important to consider to address the problems of power outage, power plant failures, and disaster areas. Distributed generation (DG) is a promising approach for such cases as it allows quick on-site installation and generation of electric power. Injection of DG can improve the system voltage profile and also reduce the system's total power losses. However, the placement and sizing of the DG unit is an optimization problem in the radial distribution system. As a test case, this study examines voltage profile improvement and system power losses for an 11 KV residential feeder at the Abdul Rehman Baba grid station in Pakistan, which is modelled using the Electrical Transient Analyzer Program (ETAP). For various scenarios, several tests are conducted to assess the effects of DG on the distribution system. The results show that proper design considerations of size and location of a D...
Electronics
In this article, a compact four-port MIMO antenna system resonating from 4.7–5.1 GHz on −6 dB cri... more In this article, a compact four-port MIMO antenna system resonating from 4.7–5.1 GHz on −6 dB criteria is discussed. The proposed antennas are arranged in a perpendicular manner providing diversity with good isolation characteristics. The proposed antenna was fabricated and designed on a commercially available low-cost FR-4 substrate with a relative permittivity of 4.4. The total size of the antenna is 40 × 40 mm2, and a minimum isolation of 25 dB was observed at most nearby resonating elements. The proposed antenna was fabricated and tested at an in-house facility, and the measured results agree well with the simulations. The MIMO antenna characteristics, such as the envelope correlation coefficient (ECC) among any two radiating elements, have been found to be less than 0.1, and the diversity gain (DG) value evaluated showed that the proposed antenna is well designed. Furthermore, the SAR analysis showed that the desired antenna system is safe for users, with a value of 0.94 W/Kg. ...
2017 IEEE Applied Power Electronics Conference and Exposition (APEC), 2017
In order to reduce the system cost, volumetric size and weight of an electric vehicles (EVs) batt... more In order to reduce the system cost, volumetric size and weight of an electric vehicles (EVs) battery charger, a novel four-switch two-leg VSI configuration is propose for rapid battery charging with the active power filter (APF) features. It consists of cost-effective two-arm bridge converter, coupling inductors, LC filters, buck converter and EV battery. Note that the conventional three-leg bridge structure is reduce to two-leg VSI structure, functioning like three-phase rectifier to converts power from ac-dc during the battery charging process. The third-leg and set of power switching devices are eliminate by directly connecting the grid phase with the negative terminals of dc-link capacitor. Therefore, third leg of the EV charger is use as a buck converter for battery charging. The charger controller ensures the rapid charging capabilities in constant current and constant voltage (CC-CV) modes, with additional functions of harmonic compensation capability, power factor correction...
Energies
This paper investigates the impact of tube wells on the discharge and water table of the Quetta V... more This paper investigates the impact of tube wells on the discharge and water table of the Quetta Valley aquifer and conducts a financial analysis of the solar photovoltaic water pumping system (SPVWP) in comparison with a typical pumping system for the Water and Sanitation Agency of Quetta’s (WASA) tube wells. Quetta Valley is dependent on groundwater as surface resources are on decline and unpredictable. The population of this city has exponentially increased from 0.26 million in 1975 to 2.2 million in 2017 which has put a lot of pressure on the groundwater aquifer by installing more than 500 large capacity tube wells by WASA and Public Health Engineering (PHE) departments in addition to thousands of low-capacity private tube wells. The unprecedented running of these wells has resulted in drying of the historical Karez system, agricultural activities, and the sharp increase in power tariffs. There are 423 tube wells in operation installed by WASA in addition to PHE, Irrigation and M...
Energies
Electric vehicles’ (EVs) technology is currently emerging as an alternative of traditional Intern... more Electric vehicles’ (EVs) technology is currently emerging as an alternative of traditional Internal Combustion Engine (ICE) vehicles. EVs have been treated as an efficient way for decreasing the production of harmful greenhouse gasses and saving the depleting natural oil reserve. The modern power system tends to be more sustainable with the support of electric vehicles (EVs). However, there have been serious concerns about the network’s safe and reliable operation due to the increasing penetration of EVs into the electric grid. Random or uncoordinated charging activities cause performance degradations and overloading of the network asset. This paper proposes an Optimal Charging Starting Time (OCST)-based coordinated charging algorithm for unplanned EVs’ arrival in a low voltage residential distribution network to minimize the network power losses. A time-of-use (ToU) tariff scheme is used to make the charging course more cost effective. The concept of OCST takes the departure time o...
Sustainability
This study summarizes a critical review on EVs’ optimal charging and scheduling under dynamic pri... more This study summarizes a critical review on EVs’ optimal charging and scheduling under dynamic pricing schemes. A detailed comparison of these schemes, namely, Real Time Pricing (RTP), Time of Use (ToU), Critical Peak Pricing (CPP), and Peak Time Rebates (PTR), is presented. Globally, the intention is to reduce the carbon emissions (CO2) has motivated the extensive practice of Electric Vehicles (EVs). The uncoordinated charging and uncontrolled integration however of EVs to the distribution network deteriorates the system performance in terms of power quality issues. Therefore, the EVs’ charging activity can be coordinated by dynamic electricity pricing, which can influence the charging activities of the EVs customers by offering flexible pricing at different demands. Recently, with developments in technology and control schemes, the RTP scheme offers more promise compared to the other types of tariff because of the greater flexibility for EVs’ customers to adjust their demands. It h...
Sustainability
The uncoordinated integration of electric vehicles (EVs) severely deteriorates the operational pe... more The uncoordinated integration of electric vehicles (EVs) severely deteriorates the operational performance of a distribution network. To optimize distribution network performance in an EV charging environment, this paper presents a two-stage optimization approach, which integrates coordinated EV charging with network reconfiguration. A formulation to minimize system power loss is presented, and an optimal solution is obtained using a binary particle swarm optimization algorithm. The proposed approach is tested on a modified IEEE 33-bus medium-voltage node test system, coupled with a low voltage distribution network. Results of the coordinated and uncoordinated EV charging are compared with those of the developed integrated approach, and the operational performance of the system is studied. The results show that the integration of network reconfiguration with coordinated EV charging significantly decreases network power losses and fairly improves voltage profile. Thus, the proposed s...
Sustainability
Pakistan is a developing country that is experiencing a shortage of electricity generation due to... more Pakistan is a developing country that is experiencing a shortage of electricity generation due to its rapidly growing demand. The existing and upcoming energy requirements for power generation and future transportation can be met by efficient utilisation of homegrown biomass resources. Determining the present energy mix resources in various sectors of the country is important. This article analyses the biomass resources and their potential and bioenergy utilisation in Pakistan. An overview of the global renewable energy scenario is presented. This article accentuates the importance and challenges of new technologies and estimates the current and future share of power generation from renewable sources, focusing on the technical potential of biomass energy, which is obtained from agricultural residues, animal manure and municipal solid wastes in Pakistan. This paper highlights the developing technologies that are primarily used to convert biomass waste into energy and presents a criti...
Energies
Pakistan is experiencing an undersupply of electricity, causing load shedding several hours per d... more Pakistan is experiencing an undersupply of electricity, causing load shedding several hours per day due to the adherence to conventional energy resources having quantitative and environmental limitations. Fossil fuels generate more than half of the country’s total electricity, but they will ultimately run out due to their limited supply. Their combustion emits greenhouse gases, posing environmental threats. Since the world is tending toward efficient and sustainable alternative methods for harvesting energy from nature, Pakistan has also been investigating an elevated deployment of renewable energy projects. This paper presents a critical analysis of the present energy sector of Pakistan along with global scenarios. Pakistan relies on mainly thermal, hydro, and nuclear energy for power generation. National solar, wind, geothermal, and biomass resources have not been extensively explored and implemented. This paper provides an insight into the potential of these resources in Pakistan...
IEEE Transactions on Power Electronics
Energies, 2017
Uninterruptible power supplies (UPSs) are widely used to deliver reliable and high quality power ... more Uninterruptible power supplies (UPSs) are widely used to deliver reliable and high quality power to critical loads under all grid conditions. This paper proposes a high-frequency isolated online UPS system for low power applications. The proposed UPS consists of a single-stage AC-DC converter, boost DC-DC converter, and an inverter. The single-stage AC-DC converter provides galvanic isolation, input power factor correction, and continuous conduction of both input and output current. The low battery bank voltage is stepped up to high dc-link voltage by employing a high voltage gain boost converter, thus allows the reduction of battery bank to only 24 V parallel connected batteries. Operating batteries in parallel improves the battery performance and resolves the issues related to conventional battery banks that arrange the batteries in series combination. The inverter provides regulated output voltage to the load. A new cascaded slide mode (SM) and proportional-resonant (PR) control for the inverter has been proposed, which regulates the output voltage for both linear and non-linear loads. The controller shows excellent performance during load transients and step changes. Besides, the controller for boost converter and AC-DC converter is presented. Operating principle and experimental results of 1 kVA laboratory setup have been presented for the validation of proposed system.
Energies, Jun 7, 2018
This study summarizes an analytical review on the comparison of three-phase static compensator (S... more This study summarizes an analytical review on the comparison of three-phase static compensator (STATCOM) and active power filter (APF) inverter topologies and their control schemes using industrial standards and advanced high-power configurations. Transformerless and reduced switch count topologies are the leading technologies in power electronics that aim to reduce system cost and offer the additional benefits of small volumetric size, lightweight and compact structure, and high reliability. A detailed comparison of the topologies, control strategies and implementation structures of grid-connected high-power converters is presented. However, reducing the number of power semiconductor devices, sensors, and control circuits requires complex control strategies. This study focuses on different topological devices, namely, passive filters, shunt and hybrid filters, and STATCOMs, which are typically used for power quality improvement. Additionally, appropriate control schemes, such as sinusoidal pulse width modulation (SPWM) and space vector PWM techniques, are selected. According to recent developments in shunt APF/STATCOM inverters, simulation and experimental results prove the effectiveness of APF/STATCOM systems for harmonic mitigation based on the defined limit in IEEE-519.
Renewable and Sustainable Energy Reviews, 2017