Informatics Publishing Limited

Rajashekar P. Mandi ¹, S. Seetharamu ², Udaykumar R. Yaragatti ³

Affiliations
1 Energy Efficiency & Renewable Energy Division, Central Power Research Institute, Bangalore – 560 080, IN
2 Director, Central Power Research Institute, Bangalore – 560 080, IN
3 National Institute of Technology Karnataka, Surathakal – 575 025, IN

Abstract

Primary Air Fans are the essential auxiliary equipment to provide the primary air to lift the pulverized coal from mills to carry to burners and also to provide partial air for combustion. This paper describes various techno-economical energy conservation measures for reducing the carbon emission by improving the performance of Primary Air fans in coal fired thermal power plants based on the energy conservation/audit study conducted in 28 numbers of 210 MW power plants in India. The best operating points for pressure gain, flow, pressure drop across hydrodynamic resistive elements, equipment efficiency, power input and specific energy consumption are simulated by using MATLAB and presented in this paper with case study to validate the results. Optimizing the pressure at PA fan discharge, control of excess air, pressure drop across APH and mills and maintaining the optimum primary air pressure at mills thereby to maintain appropriate coal-air pressure at burners will help in reduction of auxiliary power of PA fans. The implementation of energy conservation measures in a typical 210 MW coal fired thermal power plant reduce the overall auxiliary power of PA fans by 0.26 % of gross energy generation and also reduce the carbon emission by 4,056 t/year.

Keywords

Energy efficiency, carbon emission, primary air fans, excess air, auxiliary power, fan efficiency

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Rajashekar P. Mandi ¹, Udaykumar R. Yaragatti ²

Affiliations
1 Energy Efficiency & Renewable Energy Division, Central Power Research Institute, Bangalore - 560 080, IN
2 National Institute of Technology Karnataka, Surathakal, Mangalore, IN

Abstract

This paper describes the various opportunities for reducing the auxiliary power of induced draft fans in coal fired thermal power plants. The auxiliary power used by induced draft fans forms about 0.9 to 1.18 % of the total gross energy generation for 210 MW to 800 MW power plants. ID fans are the second largest (in rating) motor in a thermal power plant after Boiler Feed Pump (BFP). The detailed energy audit of auxiliary equipment in various thermal power stations, operational optimization and appropriate control system had shown ample scope for improving the energy efficiency of induced draft fans. The implementation of energy conservation measures reduce the average auxiliary power used by ID fans for 210 MW plant from average value of 1.18 % to 0.90 % of gross energy generation and the energy conservation schemes are economically attractive with a payback period of 1 to 5 years.

Keywords

Thermal power plant, Auxiliary power, HT motors, Fans, Pumps, Mills.

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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)

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Rajashekar P. Mandi ¹, Udaykumar R. Yaragatti ²

Affiliations
1 Energy Efficiency & Renewable Energy Division, Central Power Research Institute, Bangalore-560080, IN
2 National Institute of Technology Karnataka, Surathakal-574157, IN

Abstract

This paper describes the various methods for enhancing the energy efficiency of Boiler Feed Pumps (BFP) in thermal power plants. The specific auxiliary power used by BFPs vary between 2.2 to 3.6 % of the total gross energy generation for units ranging from 30 MW to 800 MW units. The average specific power used by BFPs for 210 MW plants is 2.4 to 3.2 % of gross energy generation. The energy efficiency improvement of BFPs by reducing the re-circulation flow, pressure drop across feed water circuit elements, enhancing overall efficiency of BFPs, etc., are discussed with case studies. The implementation of energy conservation measures reduce the average auxiliary power used by BFPs for 210 MW plant from average value of 3.6 to 2.3 % of gross energy generation and release an additional power of about 10.9 MU/year for one 210 MW unit.

Keywords

Energy Efficiency, Boiler Feed Pumps, Auxiliary Power, Pump Efficiency, Sec, Energy Conservation

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Rajashekar P. Mandi ¹, Udaykumar R. Yaragatti ²

Affiliations
1 Energy Efficiency & Renewable Energy Division, Central Power Research Institute, Bangalore-560080, IN
2 National Institute of Technology Karnataka, Surathakal, Mangalore-575025, IN

Abstract

Energy is the prime mover of the economic growth and developmental process. To enhance the energy security of India, use of renewable energy is the utmost important. Electrical energy is the richest form of energy which is having an important role in Industrial growth. Depleting fossil fuel resources which form about more than 60 % of Indian energy generation cannot prime the growth process that is sustainable. They need to be gradually replaced by renewable sources of energy, which are perennial in nature. The increasing gap between power supply and demand is alarming the power industry to work hard in reducing the gap. In order to achieve the sustainable energy growth with the increased population and energy demand and to provide more energy to the rural populations, the non-conventional and renewable energy sources need to be installed and used [1]. The energy resource like solar radiation & wind data are measured, the energy availability, reliability of energy systems and economics of the systems are carried out by using a HOMER and MATLAB Simulink software. This paper discusses about the improving of energy efficiency by hybridization of different forms of renewable energy sources with respect to energy availability, reliability, cost, ease of operation and maintenance, etc, with detailed discussion.

Keywords

Hybrid Energy Systems, Renewable Energy Sources, Life Cycle Costing, Optimal Hybridization, Energy Efficiency

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Rajashekar P. Mandi ¹, Udaykumar R. Yaragatti ²

Affiliations
1 Energy Efficiency & Renewable Energy Division, Central Power Research Institute, Bangalore-560080, IN
2 National Institute of Technology Karnataka, Surathakal, Mangalore-575025, IN

Abstract

This paper describe the sizing of solar PV, DG set and battery bank Hybrid Power System (HPS) for different configuration for share of solar &diesel power. Different configurations for integration of solar PV with diesel energy systems are explained in detail. The energy availability and economics of the integrated energy system are highlighted

Keywords

Solar Photovoltaic Energy Systems, Integration of Renewable Energy, Life Cycle Costing, Optimal Hybridization.

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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)

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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)

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Rajashekar P. Mandi ¹, Janak J. Patel ², Hitesh R. Jariwala ², Ankur Vashi ³

Affiliations
1 Energy Effi ciency & Renewable Energy Div, Central Power Research Institute, Banglore 560 080, IN
2 Department of Electrical Engineering, Ichhanath, SVNIT, Surat - 395 007, IN
3 Student, Department of Electrical Engineering, Ichhanath, SVNIT, Surat - 395 007, IN

Abstract

An arc of an electric arc furnace as a virtual short circuit is purely resistive load but the reactor connected in series with primary of furnace transformer to smoothen the arc makes the total combination as an inductive load, with its fluctuating active and reactive power requirements, it leads to power quality issues such as poor power factor, harmonic generation, etc. This paper presents measurement and analysis of harmonics generated by alternate current electric arc furnace (AC EAF) and laddle furnace (LF) loads and also defines terms like harmonics, total harmonic distortion etc. Harmonic Filter Banks (HFB) of static Var compensator (SVC) are tuned to particular order of frequency to provide least resistance path to that order of harmonics for elimination. This paper also describes design criteria for harmonic filter banks of 100 Hz, 150 Hz and 200 Hz and presents the SVC as a solution for control of harmonics. The final results are compared with allowable limits set by international standards.

Keywords

Alternate current electric arc furnace (AC EAF), Laddle furnace (LF), Harmonics, Total harmonic distortion, Harmonic fi lter banks (HFB) and Static Var compensators (SVC)

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Rajashekar P. Mandi ¹, Janak J. Patel ², Hitesh R. Jariwala ², Ankur Vashi ²

Affiliations
1 Energy Effi ciency and Renewable Energy Division, Central Power Research Institute, Bangalore - 560 080, IN
2 Department of Electrical Engineering, SVNIT, Surat - 395 007, Gujarat, IN

Abstract

An electric arc is purely resistive load, but the series connected reactor to smoothen the arc makes the combination inductive load creating power quality issues like harmonic generation, poor power factor, voltage flickers etc. An electric arc furnace is heart of integrated steel plant used for smelting of steel with help of electric arc. Temperatures insider the furnace can reach up to 1800° centigrade and capacity wise electric arc furnaces are available from 1–300 tonnes. The charged material is directly exposed to the electric arc and results into hot liquid steel. The charged material can be steel scrap, direct reduced iron and hot metal. The electric arc furnace can be classified as alternate current electric arc furnace (AC EAF) and direct current electric arc furnace (DC EAF) depending upon source of power used at furnace for arcing. The objective of this review is to compare the configuration and harmonics generated by operation of AC EAF and DC EAF. Static Var compensator (SVC) is solution to mitigate the power quality issues generated by the electric arc furnace. This review also compares configurations of the SVCs used for AC EAF and DC EAF.

Keywords

AC EAF, DC EAF, SVC, Harmonic fi lter bank (HFB) and Total demand distortion (TDD)

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Rajashekar P. Mandi , Udaykumar R. Yaragatti

Abstract

This paper describes the auxiliary power consumption in Indian coal-fired thermal power plants. The factors influencing the auxiliary power are discussed in detail increase in auxiliary power due to lower plant load factor causes for lower PLF are enumerated. The effect of poor coal quality on auxiliary power is discussed. The effect of operational optimization, adoption of new energy efficient technologies, design deficiencies, etc., is discussed in detail along with remedial measures to reduce the auxiliary power. The energy conservation measures reduce the auxiliary power of 210 MW power plant from 11.59% to 8.50% with a payback period of 1-5 years.

Keywords

Auxiliary Power, Energy Efficiency, Plant Load Factor, Coal Quality, Operational Optimization.

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Rajashekar P. Mandi ¹, Udaykumar R. Yaragatti ²

Affiliations
1 Energy Effi ciency and Renewable Energy Division, Central Power Research Institute, Bangalore, IN
2 National Institute of Technology Karnataka, Surathakal, Mangalore, IN

Abstract

This paper describes the results of enhancing energy effi ciency of hydro turbines by implementing the energy conservation measures for hydro turbine generators. The procedure for evaluating the on-line performance of generators is discussed. The energy saving in generators by maintaining optimum generator terminal voltage, by reducing the stator winding temperature, by improving the performance of coolers and reducing the excitation loss by appropriate tuning of excitation system are enumerated in detail with case studies. The implementation of energy conservation measures has a techno-economic feasibility with a payback period of 1–5 years.

Keywords

Generator, Hydro turbine, Energy effi ciency, Stator copper loss, Rotor copper loss, Generator cooling, Generator excitation.

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