Informatics Publishing Limited

K. J. Shruthi ¹, P. Giridhar Kini ², C. Viswanatha ³

Affiliations
1 Instrumentation Division, Central Power Research Institute, IN
2 Department of Electrical and Electronics Engineering, Manipal Institute of Technology, IN
3 Diagnostics Cables and Capacitors Division, Central Power Research Institute, IN

Abstract

Field solar radiation measurement is very essential to estimate the conversion efficiency of the solar photovoltaic (PV) system. Pyranometers, instrument used for solar radiation measurement are very expensive and require regular calibration and increasing maintenance cost. This paper provides an alternative low cost solution to estimate the solar radiation received on field. The paper addresses the design and development of MSP430G2553 microcontroller based data logger for measurement of the solar panel voltage and current output. The design is based on maximum power point tracking technique using 16-bit microcontroller to measure, analyse and compute the instantaneous maximum power of solar PV panel. The data is communicated through RS485 onto storage device for future analysis. The experimental analysis is carried out in Bengaluru co-ordinates. The estimated solar radiation is compared with recordings from a calibrated pyranometer. The loggers required very low power requirement and can be powered by the parent panel on which they are mounted thus avoiding requirement of grid. This feature makes it ideal for use in rural side field PV analysis. The developed SPV logger gives accurate measurement of solar PV output and aide in estimation of incoming solar irradiance.

Keywords

Solar Photovoltaic (SPV), Irradiation Calculation, Pyranometer, Optimized Power Measurement, Microcontroller.

Full Text

     

Vani Vijay ¹, C. Viswanatha ², P. Giridhar Kini ³

Affiliations
1 Senior Research Fellow, Energy Efficiency and Renewable Enenrgy Division, Central Power Research Institute, Bangalore- 560080, IN
2 EEE Department, Manipal Institute of Technology, Manipal - 576104, IN
3 Diagnostics Cables and Capacitors Division, Central Power Research Institute, Bangalore - 560080, IN

Abstract

Using load emulation, the performance of source side converters can be easily evaluated and improved without the need for actual load. Due to the increase in use of power electronic converters and SMPS based systems, the harmonic levels in load side has increased considerably. Hence emulation of variable THD load is very important in analysing the performance of source side converters and ensure the performance efficiency and power quality under such loads. Here a novel method of obtaining variable load using PWM control explained. The PWM is controlled in a rainbow sinusoidal fashion to obtain clipped waveform across a resistor so that harmonics is introduced in the Load. The power factor can also be varied in the system by paralleling it with leading and lagging converter circuits. The working principle, modelling and simulation are presented along with the results. Proposed technique provides accurate modulation of load THD and effect of harmonics loads on sources converter are also analysed using this.

Keywords

Load Emulation, harmonic loads, current clipping

Full Text

     

Vani Vijay ¹, C. Viswanatha ², P. Giridhar Kini ³, R. Sudhir Kumar ⁴

Affiliations
1 Senior Research Fellow, Energy Efficiency and Renewable Enenrgy Division, Central Power Research Institute, Bangalore - 560080, IN
2 Electrical and Electronics Engineering department, Manipal Institute of Technology, Manipal - 576104, IN
3 Diagnostics Cables and capacitors Division, Central Power Research Institute, Bangalore - 560080, IN
4 Energy Efficiency and Renewable Energy Division, Central Power Research Institute, Bangalore - 560080, IN

Abstract

Solar Photo Voltaic (SPV) sources are widely used in present scenario of energy crisis for various applications including grid connected PV plants and grid isolated standalone applications. The performance of solar PV system is highly dependent upon the operating conditions of source and loads especially in standalone applications. The effect on various types of loads on standalone system can be easily analyzed at design stage and testing stage by using load emulation technique, where a virtual load is used to replace actual load, giving more flexibility and accuracy to loading conditions. Here a novel load emulator model is presented which can provide accurate variation in load power factor and THD compared to existing models. The converter decouples the current in to in phase and out of phase components and the in phase component can be regenerated. The model is simulated using MATLABTM simulation and the results are validated by comparing with experimental results obtained by loading SPV inverter with actual load. Hence the proposed load emulator is very useful in design and development of application specific solar PV systems and also for performance analysis of such systems based on various standards.

Keywords

Solar PV inverters, non-linear loads, low pf loads

Full Text

     

C. Viswanatha ¹, V. Mohan Babu ², K. G. Rakesh ³

Affiliations
1 Joint Director, DCCD, Central Power Researh Institute, Bangalore - 560080, IN
2 Engineering Assistant, DCCD Central Power Researh Institute, Bangalore - 560080, IN
3 Engineering Assistant, DCCD, Central Power Researh Institute, Bangalore - 560080, IN

Abstract

The circuit breaker of SF₆ type has many advantages over conventional type, being better performance and dielectric properties. SF₆ circuit breaker are now being employed widely in substations for better electrical network functioning. Even then, it is associated with some failures which are reported in the field. Two kinds of circuit breaker are studied in this work with point of thermal behavior. A rated current is passed through SF₆ circuit breaker and thermal mapping is recorded at incoming terminal and outgoing terminal, enclosure and other points for investigations. The steady state condition of temperature is taken as reference in finding temperature rise over the environment condition. The temperature at predecided points of circuit breaker both for passed sample and failed sample are recorded. The data obtained is analyzed and attempt is made to understand the failure of SF₆ breaker in the context of excessive temperature than the prescribed limits of International Specifications. This paper deals with sample arrangement, experimental details, results and analysis. Both failed sample and passed sample have shown contrast performance in final analysis.

Keywords

Circuit breaker, temperature, thermal mapping, steady state, SF6 gas, thermocouples.

Full Text

     

Vani Vijay ¹, P. Giridhar Kini ², C. Viswanatha ³, K. Pradeep ⁴

Affiliations
1 Energy Efficiency and Renewable Enenrgy Division, Central Power Research Institute, Bangalore- 560080, IN
2 E&E Department, Manipal Institute of Technology, Manipal - 576104, IN
3 Diagnostics Cables and capacitors Division, Central Power Research Institute, Bangalore - 560080, IN
4 Energy Efficiency and Renewable Energy Division, Central Power Research Institute, Bangalore - 560080, IN

Abstract

Efficiency of power electronics devices are highly dependent on temperature. Hence temperature compensation and heat sink design are very important factors in maintaining the performance quality of power electronic converters. Thus the ambient temperature at which the device is operating also effects the performance since the heat removal by heat sinks or cooling fans is affected by the ambient temperature. Here a detailed analysis of the dependency of losses in power electronic switches on the junction temperature and in turn ambient temperature is presented. A theoretical Analysis of conduction losses and effect of ambient temperature on it is presented along with a set of experimental results by analyzing the performance of a 850W Solar PV inverter at various ambient temperatures. The results are satisfactorily explaining the effect of ambient temperature on converter efficiency.

Keywords

Solar PV inverters, conduction Losses, heat sink, ambient temperature

Full Text

     

C. Viswanatha ¹, G. P. Vittal ¹, V. Mohan Babu ¹

Affiliations
1 DCCD, Central Power Research Institute, Bangalore- 560080, IN

Abstract

Different types of busducts like Isolated Phase Busduct, Segregated and Non Segregated Busducts are used in Power Distribution Network which occupies voluminous, large space of the equipment. Recently, Sandwich Busducts have come into vogue because of their compactness, light weight, low impedance, and fire retardancy besides several other advantages. However Sandwich Busducts need to maintain high quality conductors, superior design, high dielectric withstand voltage. These properties would meet the requirements of electrical parameters but for the requirement of thermal specifications, it is Temperature rise method widely employed to monitor the thermal performance of Sandwich Busducts. In the present investigation, modular designed Sandwich Busducts are chosen and studied using Temperature rise method. The samples of Sandwich Busducts are subjected to Temperature rise method. The temperature at critical points of Sandwich Busducts are monitored and evaluated in the light of International Specifications. Of the many inferences derived, the important observations at thermal steady state for busduct, incoming and outgoing terminals have been obtained. The present paper focuses on assessing the components forming Sandwich Busduct for their evaluation to apply to field conditions in the Electrical Power System Network.

Keywords

Sandwich busduct, temperature rise,busduct, thermal profile, insulation

Full Text

     

Vani Vijay ¹, P. Giridhar Kini ², C. Viswanatha ³, S. Jothi Basu ⁴

Affiliations
1 Energy Efficiency and Renewable Enenrgy Division, Central Power Research Institute, Bangalore - 560080, IN
2 E&E Department, Manipal Institute of Technology, Manipal - 576104, IN
3 Diagnostics Cables and capacitors Division, Central Power Research Institute, Bangalore - 560080, IN
4 Energy Efficiency and Renewable Energy Division, Central Power Research Institute, Bangalore - 560080, IN

Abstract

AC-DC converters are very commonly used in many power electronics applications including controllable sources and machine drives. Rectifier circuit results in harmonic distortions in AC side and requires large capacitive filter for reducing DC ripples on the output side. Use of active power factor technique can be utilized for solving this issue resulting in better performance of the converter. It basically consists of boost converter with high frequency switching following the rectifier controlled using a suitable microcontroller. This paper presents the detailed design and operation of Active power factor corrected rectifier which operates with reduced THD and improved power factor there by reducing losses in power flow and utility. Simulation of the designed converter and comparison with conventional topology is also discussed.

Keywords

Rectifier; active power factor correction, capacitive filtering

Full Text

     

K. J. Shruthi ¹, P. Giridhar Kini ², C. Viswanatha ³, Rajashekar P. Mandi ⁴

Affiliations
1 Energy Efficiency and Renewable Energy Division, Central Power Research Institute, Bangalore- 560080, IN
2 E&E department, Manipal Institute of Technology, Manipal 576104, IN
3 Diagnostics Cables and capacitors Division, Central Power Research Institute, Bangalore 560080, IN
4 Energy Efficiency and Renewable Energy Division, Central Power Research Institute, Bangalore -560080, IN

Abstract

Renewable energies are the most sought after alternatives for electric energy generation. The improvement in semiconductor and power electronics technology has led to precise operation of system at maximum power point, thus increasing the efficiency of the PV system. Many maximum power point tracking (MPPT) algorithms have been developed in recent times which provide maximum power tracking under varying conditions. Among the existing algorithms, perturb and observe (P & O) is the most explored technique. In this paper a comparison between the conventional P & O and improved P & O method is brought about. A MATLAB simulink based simulation study of PV module/ array is carried out and both the MPPT algorithms are explored for z-source inverter in photovoltaic system.

Keywords

Solar Photovoltaic (SPV) system, Modeling of PV arrays, Z-source inverter (ZSI), Perturb and Observe (P & O), Improved perturb and observe (IP & O), Maximum power point tracking (MPPT)

Full Text

     

Vani Vijay ¹, P. Giridhar Kini ², C. Viswanatha ³, S. Jothi Basu ⁴

Affiliations
1 Energy Efficiency and Renewable Enenrgy Division, Central Power Research Institute, Bangalore-560080, IN
2 E & E Department, Manipal Institute of Technology, Manipal-576104, IN
3 Diagnostics Cables and capacitors Division, Central Power Research Institute, Bangalore-560080, IN
4 Energy Efficiency and Renewable Energy Division, Central Power Research Institute, Bangalore-560080, IN

Abstract

Inverter and power conditioning circuit is the most important part of solar PV system which is responsible for providing the AC output as per the requirement of the application. The presence of AC harmonics and DC ripples in the inverter is still an unavoidable drawback, even though it has reduced to a great extent in past two decades. This paper presents a detailed study of distortions in the AC and DC sides of commercial standalone single phase Solar PV inverter and the effect of the same in the application. The harmonic content is evaluated by loading the inverter using electronic loading. The reduction in distortions in the AC and DC sides by utilization of a high impedance network on the DC side of the inverter is also evaluated by simulation. A comparative study of harmonics and DC ripples in the inverter under test and the simulated impedance source inverter is also presented.

Keywords

Harmonics, Stand alone Solar PV inverters, DC ripples, Impedance network

Full Text

     

Vani Vijay ¹, Kini P. Giridhar ², C. Viswanatha ³, S. Jothi Basu ⁴

Affiliations
1 Energy Efficiency and Renewable Enenrgy Division, Central Power Research Institute, Bangalore- 560080, IN
2 E&E department, Manipal Institute of Technology, Manipal 576104, IN
3 Diagnostics Cables and capacitors Division, Central Power Research Institute, Bangalore 560080, IN
4 Energy Efficiency and Renewable Energy Division, Central Power Research Institute, Bangalore -560080, IN

Abstract

Back to back converters are used in many applications including machine drives and HVDC links. It is a combination of AC to DC and DC to AC converters with topologies suitable for the application. Here a single phase converter topology is developed by combining a Z source network and HERIC inverter which operates with lesser losses and more controllability. Compared to conventional inverter model, the conduction losses are much less in HERIC configuration. The Z source network help in boosting the DC voltage level so as to obtain the required level of AC output. This back to back converter is mainly meant for regenerative load application which can be utilized in equipment testing. The power drawn by the converter can be regenerated to supply back to the utility grid there by it is possible to conduct equipment testing without wasting energy. The details of the proposed configuration and the output wav forms are explained. Also a comparative study of the losses in conventional converter and proposed converter is presented.

Keywords

Back to back converter, HERIC inverter, Z source nettwork, regenerative load

Full Text

     

K. J. Shruthi ¹, Rajashekar P. Mandi ¹, Pradeep K. ¹, C. Viswanatha ², Kini P. Giridhar ³

Affiliations
1 Energy efficiency and Renewable Energy Division (ERED), Central Power Research Institute, Bangalore-560080, IN
2 Diagnostics Cables and Capacitors Division (DCCD), Central Power Research Institute, Bangalore-560080, IN
3 Professor, Electrical and Electronics Engineering Dept., Manipal Institute of Technology, Manipal, IN

Abstract

The key requirements for the control of the solar photovoltaic (SPV) energy conversion systems are to achieve very fast yet quite accurate tracking of the maximum power point under rapidly changing environmental conditions and to obtain efficient unperturbed tracking operation under steady environmental conditions. In this work, a high-performance Maximum Power Point Tracking (MPPT) technique, based on one cycle control (OCC), is proposed to meet these challenging requirements. This paper proposes single phase z-source inverter with maximum power point tracking using OCC for solar photovoltaic power generation. OCC is based on output current adjustment according to the voltage of photovoltaic array so as to extract the maximum power from it. A 1 kW grid-tied roof-top system is designed using the OCC method for MPP. Analysis & simulation using MATLAB tool, is carried out to validate the proposed technique.

Keywords

Grid-tied transformerless inverter, photovoltaic (PV) system, z-source network, Maximum power point tracking (MPPT), One Cycle Control (OCC)

Full Text

     

K. Sornalatha ¹, N. Rajkumar ¹, K. Pradeep ¹, C. Viswanatha ², Giridhar P. Kini ³

Affiliations
1 Energy Efficiency and Renewable Energy Division, Cental Power Research Institute, Bangalore-560 080, IN
2 Diagnostics Cables and Capacitors Division, Central Power Research Institute, Bangalore 560 080, IN
3 Dept. of Electrical and Electronics Engg., Manipal institute of technology, Manipal,Karnataka- 576 104, IN

Abstract

This paper throws light on application of synchronised phasor measurement in renewable energy systems. Power generation from renewable energy system connected to the grid is highly dynamic, nonlinear which needs to be monitored continuously for efficient and reliable system. There are various methods of monitoring of power from renewable energy system to grid. Nowadays, Time synchronisedphasormeasuring method proves to be a revolutionary method for power system monitoring. Synchronised PMU has wide application such as wide area monitoring, Real time monitoring, post even analysis, visualization, state estimation etc. They are employed in micro grid and distributed generation plants mainly for solving islanding issues. This paper summarises the synchrophasor application and its future scope in renewable energy system.

Keywords

Phasor Measurement Unit (PMU), Synchrophasor, Real-time Monitoring, State Estimation, Islanding

Full Text

     

K. J. Shruthi ¹, Rajashekar P. Mandi ¹, C. Viswanatha ², Giridhar P. Kini ³

Affiliations
1 Energy efficiency and Renewable Energy Division (ERED), Central Power Research Institute, Bangalore - 560 080, IN
2 Diagnostics Cables and Capacitors Division (DCCD), Central Power Research Institute, Bangalore - 560 080, IN
3 Professor, Electrical and Electronics Engineering Dept., Manipal Institute of Technology, Manipal - 576 104, IN

Abstract

This paper discusses the various inverter topologies used in solar photovoltaic system for electrical energy. This paper gives comparison between the conventional type of inverters i.e. voltage source inverter (VSI) and current source inverter (CSI) .New z-source inverter topology is proposed which will overcome the drawbacks in VSI and CSI. Pulse width modulated (PWM) signals are generated for the power semiconductor switches of the z-source inverter for controlling the power to the grid. The characteristics of this inverter are used to obtain maximum power tracking control and delivering to the grid.

Keywords

Inverter, Photovoltaic (PV) System, z-source network, pulse width modulation (PWM)

Full Text

     

Vani Vijay ¹, Giridhar P. Kini ², C. Viswanatha ³, S. Jothi Basu ⁴

Affiliations
1 Energy Efficiency and Renewable Enenrgy Division, Central Power Research Institute, Bangalore- 560 080, IN
2 E&E department, Manipal Institute of Technology, Manipal 576104, IN
3 Diagnostics Cables and capacitors Division, Central Power Research Institute, Bangalore 560 080, IN
4 Energy Efficiency and Renewable Enenrgy Division, Central Power Research Institute, Bangalore -560 080, IN

Abstract

All newly designed power electronic equipments are to be tested as per the standards, so as to verify the response of the equipment under various load conditions. For this, different linear, non-linear and dynamic loads are to be applied to the equipment in accordance with the applications. Load emulation is the process by which the actual load is replaced by a flexible system which can mimic the characteristics of the actual load. A regenerative operation can be implemented in power electronic emulators. Thus by using load emulators for testing, the energy lost in testing of equipments can be reduced to a great extent. Here a review of various types of load emulators is presented which are intended for various types of applications along with some experimental results obtained in various research studies.

Keywords

Load Emulation, Non-linearity, Power Regeneration, Phase Locked Loop

Full Text