Qualification: 
Ph.D, M.Tech
Email: 
preethapk@am.amrita.edu

Dr. Preetha PK currently serves as Associate Professor and Vice Chairperson at the Department of Electrical and Electronics Engineering at Amrita School of Engineering, Amritapuri. Ms. Preetha has completed  B.Tech in Electrical & Electronics Engineering and M.Tech. in Power Systems from College of Engineering, Trivandrum in the year 1995 and 1997 respectively. She is currently pursuing her Ph.D. at the department of Electrical and Electronics Engineering, Amritapuri campus of Amrita Vishwa Vidyapeetham.

Dr. Preetha joined the department in 2007. Prior to coming to Amrita, she was a faculty at Fr. Conceicavo Rodrigues Institute of Technology, Navi Mumbai from 1999 to 2007. From 1998-1999 she was with the department of Electrical & Electronics Engineering,Kumaraguru College of Technology, Coimabatore. 

Dr. Preetha is a member of IEEE and a life time member of ISTE.  She was conferred with the Certificate of Appreciation for her achievements during the academic year 2014-2015 from Amrita Vishwa Vidyapeetham, Amritapuri. 

Publications

Publication Type: Conference Paper

Year of Publication Title

2020

M. Tiwari, Sruthy V., and P. K. Preetha, “Foldable Floating Solar Array for Electric Vessel”, in 2020 Third International Conference on Smart Systems and Inventive Technology (ICSSIT), 2020.[Abstract]


This paper introduces the concept of the foldable floating solar array (FFSA) for electric vessels. As being moved from fossil-based transportation to fumeless mode, going electric is the most preferred way based on efficiency and economic viability. With an increased demand for electric transport, the number of electric ships and boats has gone up. With this increase, there is more need for energy production to fulfill the demands. To tackle this problem sustainably, integration of renewable energy with electric vessels is focused in this paper, for that the idea of a foldable floating solar array is proposed. This product is based on pre-existing technologies of floating solar farms, overhead charging and microgrid concept in an electric vessel. Such technologies provide an efficient and reliable solution to problems. In this paper, the insight about the product, its design, application, and the challenges faced are detailed. The overall system is demonstrated by using the MATLAB/Simulink model. The performance of FFSA is evaluated. The design and analysis of FFSA are detailed in this.

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2018

Sruthy V., Anagha, A., and P. K. Preetha, “A Hybrid Converter Based Topology For Solar Powered Shipboard Power Systems”, in 2018 3rd IEEE International Conference on Recent Trends in Electronics, Information Communication Technology (RTEICT), Bangalore, India, 2018.[Abstract]


International trading mainly depends upon shipping industry which uses fossil fuels as the major source of fuel for transportation. Excessive use of fossil fuels often leads to environmental pollution. It also has adverse effect on the marine eco system. Hence the fossil fuels can be replaced with renewable sources of energy such as solar energy, wind energy etc. In the conventional methods of connecting a solar panel to a grid or an isolated system, a boost converter and a voltage source inverter are generally used to power simultaneous AC and DC loads. Since the power conversion stages are more for this topology, it has reduced power processing capability. A hybrid converter topology consists of a single converter which is capable of powering both AC as well as DC loads concurrently. A hybrid converter is derived from a boost converter with a voltage source inverter bridge network. This paper presents simulation analysis of hybrid converter for shipboard systems. Simulation is done in MATLAB platform. From the analysis it is found that instead of using two separate power converters in a shipboard power system, a hybrid converter can be used which has higher AC gain, reduced losses, and reduced number of switches. Compactness of the system and higher reliability makes them best suited for shipboard power system.

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2017

K. S. Vishnu and P. K. Preetha, “Single stage inverter integrated with battery for renewable energy harvesting”, in 2017 Innovations in Power and Advanced Computing Technologies (i-PACT), Vellore, India, 2017.[Abstract]


Conventional energy generation methods and environment protection are two faces of a coin that never go hand in hand. The growing requirement in energy hence increased the importance of the renewable resources. In this scenario, inverters capable of handling this type of resources are also in demand. The inverters for renewable energy harvesting usually have multiple number of power stages that adds to the losses, affecting the efficiency of the entire system. In this work a new type of ac/dc single phase transformer-less inverter topology with single stage operation and battery charging capability is proposed. Inverter uses both buck and boost operation to handle the variable nature of the input. The battery charging is done using buck operation. The principle of operation is demonstrated through the analysis of equivalent circuit. Proposed Inverter uses instantaneous power type controlling using PI controller. A 220 V, 50Hz, 2000W simulation model was studied using MATLAB simulink and the study showed that the usage rate can be increased by incorporating the battery charging within the inverter.

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2017

N. Naufal, P. K. Preetha, and Sruthy V., “Dynamic analysis of converter based fault current limiter of an AC/DC microgrid”, in 2017 International Conference on Technological Advancements in Power and Energy ( TAP Energy), Kollam, India, 2017.[Abstract]


Over the years there has been a drastic increase in the usage of number of renewable energy resources like solar energy, wind energy etc. They exist in islanded as well as in interconnected mode with the utility system. Use of fault current limiter is an efficient way of improving the reliability of a micro grid. This paper discusses a bridge type converter based fault current limiter (FCL) having energy management capabilities. The FCL can act both as a protective device and as an energy management device. The FCL is implemented using a bridge rectifier and a boost converter. The inductor used in the boost converter is used for limiting the current during fault conditions. The energy stored in the inductor during faulted as well as normal condition is boosted and is used for powering dc loads. The dynamic analysis of the FCL is done in MATLAB Simulink. A prototype hardware model of the fault current limiter is implemented and tested to verify the effectiveness of the circuit.

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2017

N. Naufal, P. K. Preetha, and Sruthy V., “Reliability enhancement of an interconnected power system using fault current limiter”, in 2017 Innovations in Power and Advanced Computing Technologies (i-PACT), Vellore, India, 2017.[Abstract]


Renewable energy technologies are growing day by day. Whenever a new DG unit is connected to the main grid or in case of occurrence of fault there will be considerable increase in the magnitude of current in the line. Different kinds of symmetrical (LLL) and unsymmetrical (LG, LLG) faults can occur in power system, out of which the three phase short circuit fault will be the most severe one and this can result in sudden increase of current to a very high value, which exceeds the maximum rating of the protective devices used. In this paper a resistive fault current limiter is used for limiting the three phase short circuit current. Simulations are carried out to demonstrate the effectiveness of the FCL. Introduction of FCL can considerably affect the overall reliability of the system. FCL reduces the magnitude of short circuit current through the protective devices. Here the reliability of the system is analyzed in a test bed with and without FCL and the changes in the reliability indices are studied. Simulation results show that with the incorporation of FCL, the overall reliability of the system gets improved.

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2017

P. K. Preetha, Athul, M. V., Nair, P. S. C., and Dr. Manjula G. Nair, “Waste Harmonic Power Recovery from Distribution Transformer and its Controlled Consumption with Battery Support”, in 2017 International Conference on Technological Advancements in Power and Energy ( TAP Energy), 2017.[Abstract]


The increasing usage of non-linear loads in power distribution system has led to several power quality issues. The triplen harmonics due to non-linear loads are trapped in the primary delta winding of conventional delta-star configured distribution transformer. This unrecovered harmonics is usually wasted in the form of heat leading to excessive power loss and reduced life of transformer, and this wasted power is termed as drainage power. The recovery of drainage power is possible with star-star-delta_utilized distribution transformer. In this configuration, the power due to circulating harmonics can be recovered across the zero potential terminal of the delta winding. The extracted power is characterized by variable voltage and frequency. This paper presents the recovery of harmonic power from delta winding of star-star-delta_utilized configuration transformer and its controlled consumption with battery support for feeding the load. The powering of load and battery charging are with reference to State of Charge (SoC) of Lead-acid battery and the harmonic current magnitude in the tertiary.

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2017

P. K. Preetha, S. Babu, S., and Dr. Manjula G. Nair, “DC link voltage regulation in active filter using drainage power from distribution transformer”, in 1st IEEE International Conference on Power Electronics, Intelligent Control and Energy Systems, ICPEICES 2016, 2017.[Abstract]


Non-linear loads constitute a major part of loads in the modern industrial and commercial utilities. They inject harmonics to the system and the normal delta-star distribution transformer traps the injected triple-n harmonics in the primary delta winding. This leads to the deterioration and reduction in the life of transformer. Hence, a three winding star-star-delta-utilized transformer is used to trap this harmonic or drainage power in the non-linear power system. This drainage power can be used to power auxiliary loads connected across the tertiary delta winding. Also, drainage power recovery makes the system performance better as triple-n harmonics are eliminated from supply line. For balanced and unbalanced secondary non-linear loads, the tertiary power can be recovered. Also, it can be stored in rechargeable batteries to power regulated loads. In this paper, the use of battery stored drainage power for the voltage regulation in shunt active filters is being discussed. The shunt active filter using Icosφ algorithm provides better harmonic elimination of non-linear load. When a load fluctuation occurs, the dc link capacitor voltage in the filter also fluctuates. Usually, the power needed for voltage regulation is supplied by the grid. In the proposed system, the drainage power stored in the battery is used for the voltage regulation. For using shunt active filter in the YYD-utilized transformer system, the control algorithm of the filter needs to be modified in order to sustain the triple-n harmonics in the system. The power recovered from triple-n harmonics can be stored in a battery and can be further used as the energy storage element of the filter. Results analyzed using MATLAB/SIMULINK reveals that the YYD-utilized system along with shunt active filter gives better utilization of drainage power and the overall system provides harmonic elimination. © 2016 IEEE.

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2015

P. K. Preetha, Jacob, S., and Nair, P. S. C., “An equivalent circuit model for star-star-delta-utilized distribution transformer”, in IEEE Region 10 Annual International Conference, Proceedings/TENCON, 2015, vol. 2015-January.[Abstract]


In the recent years there has been excessive use of nonlinear loads in power distribution network resulting in the injection of harmonics into the utility power system. The triplen harmonics due to non-linear loads circulate in the conventional delta-star distribution transformer resulting in excessive power losses. Star-star-delta-utilized transformer is a modified distribution transformer configuration suggested recently which helps in recovering and utilizing the power wasted due to circulating harmonics in the transformer delta winding. This is achieved by connecting a load across the zero potential terminals of the tertiary delta winding of the transformer. This paper presents a three phase equivalent circuit model for the star-star-delta-utilized transformer. The proposed dependent source model is simulated and compared with the performance of the available transformer model of MATLAB Simulink. The results show that at steady state the performance of the proposed model can replicate the performance of the Simulink model. © 2014 IEEE.

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2015

P. K. Preetha, “Power Quality Improvement using FC-TCR with closed loop control”, in International Conference on Recent Innovations in Engineering and Technology, Travancore College of Engineering, 2015.

2015

P. K. Preetha, “STATCOM based control scheme for power quality improvement”, in International Conference on Recent Innovations in Engineering and Technology, Travancore College of Engineering, 2015.

2015

P. K. Preetha, “Electromagnetic Analysis of Transformer using SOLIDWORKS”, in IEEE International Conference on Technological Advancvements in Power & Energy, TAP Energy 2015, Amrita ViswaVidyapeetham, India, 2015.

2015

P. K. Preetha, “Comparison of PWM AND modified one cycle control for bridgeless zeta ac-dc converter”, in IEEE International Conference on Power and Advanced Control Engineering, Bangalore, 2015.

2015

P. K. Preetha, “Analysis of star-star-delta_utilized transformer under balanced and unbalanced load conditions”, in IEEE IAS Conference 2015 at Annual meeting'15, Dallas, Texas, 2015.

2015

P. K. Preetha, “Power Factor correction circuit with One Cycle Controlled bridgeless zeta converter for display monitors in hospitals”, in TENCON 2015 - 2015 IEEE Region 10 Conference, Holiday Inn, Sands Cotai Central Macao SAR, China, 2015.[Abstract]


Development in the field of electrical engineering is quick and commendable. Even though the nonlinear power electronic equipments introduce power quality issues, their use is unavoidable. Most of the medical equipments make use of power electronic devices. Serious issues include low input power factor and increased ripples in the input current. Many bridgeless topologies have been introduced to mitigate the above mentioned problems. Common topologies make use of buck, boost, Cuk and Sepic converters. In this paper bridgeless zeta converter with one cycle control for display monitors in hospitals has been proposed. With one cycle control, input perturbations are avoided in one switching cycle. The converter is designed to supply the load of 50W and 24V. MATLAB/Simulink model has been analyzed for various conditions. A laboratory prototype of the converter has also been made and tested for the designed values. Results of simulation have been verified with the hardware system. Power factor has been observed to be above 0.97.

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2014

P. K. Preetha, Sana, A., Anusha, B., P, K., P.V, N. Azeez, Nair, D. Manjula G., and K.R., A., “Solar LED Street Light With Brightness Control”, in Second National Conference on Power Electronics in Sustainable Energy Development(NCPE2014), Amrita VishwaVidyapeetham, Coimbatore, 2014.

2014

P. K. Preetha, “Dependent source equivalent circuit model of Star-Star-Delta_Utilized distribution transformer”, in IEEE TENCON, Bangkok, Thailand, 2014.

2013

P. K. Preetha, “Effects of drainage power recovery on power quality”, in National Conference on Technological Advancements in Power & Energy (TAP Energy 2013, 2013.

2011

P. K. Preetha, “A novel method for recovery of drainage power from distribution transformers”, in IEEE PES International Conference on Innovative Smart Grid Technologies (ISGT 2011), 2011.

Publication Type: Journal Article

Year of Publication Title

2020

Sruthy V., Raj, B., and P. K. Preetha, “An offshore floating charging station for electric ships: accessibility enhancement schemes for recharging”, Ships and Offshore Structures, pp. 1-8, 2020.[Abstract]


ABSTRACT Marine transportation is fast witnessing an increased trend towards being all electric. This work puts forth offshore electric floating charging stations (FCS) as the need of the hour for pushing forward the transition from a completely fuel-based propulsion system to electric-powered vessel. Evaluation of a solar photovoltaic-based FCS for electric ships is made in this study and it puts forward novel solutions to enhance the accessibility of ships to the FCS facility on the sea route. One of which is using a remotely operated power carrier vehicle which can be deployed from the vessels to the FCS to meet its power requirements, with suitable communication system. A prototype model of the remotely operated carrier vehicle is also made for analysis. A pole-based charging point structure scheme for FCS is proposed as another solution to access FCS facilities and an initial feasibility evaluation of floating charging stations is also considered in this study.

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2014

P. K. Preetha and Nair, P. S. Chandra, “Drainage Power Recovery from Distribution Transformers”, Hydel Technical Journal of KSEB Engineer’s Association (KSEBEA), vol. 60, pp. 27-30, 2014.

Publication Type: Conference Proceedings

Year of Publication Title

2019

Sruthy V., Raj, B., P. K. Preetha, and Ilango Karuppasamy, “SPV based Floating Charging Station with Hybrid Energy Storage”, 2019 IEEE International Conference on Intelligent Techniques in Control, Optimization and Signal Processing (INCOS). IEEE, Tamilnadu, India, 2019.[Abstract]


This paper is proposing a solar photovoltaic based floating charging station (FCS) for marine electric vehicles. The floating charging station can be made useful to all electric marine vehicles during their course of voyage without diverting to port for recharging. The marine charging stations act as self-sustained structures entirely relied on renewable energy generation and hybrid storage system technologies. The marine vessel can meet their energy requirement by bidding with the charging stations via proper communication systems. Floating solar power plant stations is an advanced approach of using photovoltaic modules on water infrastructures to conserve the land along with marine application. This proposed floating charging station with a hybrid energy storage system is designed and verified using MATLAB/Simulink model. The performance of FCS is evaluated. The design and analysis of FCS is detailed in this by considering various load conditions and storage charge controller.

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1997

P. K. Preetha, “Synchronous Voltage Source (SVS) for Dynamic Compensation of AC Transmission Systems”, 2nd National Seminar on Modern Trends in Power Engg& Development conducted by KSEB & published subsequently in the proceedings of the Seminar. 1997.

Faculty Research Interest: