Conference Proceedings

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A fast and effective method for assessing insulation condition based on time domain spectroscopy data
(IEEE, 2022-01-21) Mishra, Deepak; Pandey, Sandeep; Baral, Arijit
A novel methodology is suggested to predict the condition of Oil-paper Insulation (OPI), popularly used in power transformers. The proposed method is based on transient measurement of polarization current data from laboratory samples. Initially, complete polarization current profile is used to formulate an insulation model and then find the rise time of the system. After that, a relation is provided between rise time and measured performance parameters like moisture content(%pm). Further, another relation is suggested between rise time and the initial decay rate of recorded data. Hence, just by knowing the value of the initial decay rate, the value of crucial parameters like %pm can be evaluated using the proposed relationship.
A method to predict degree of polymerization value of oil-paper insulation using interfacial charge
(IEEE, 2029-12-20) Singh, Vijeta; Mishra, Deepak; Baral, Arijit; Chakravorti, Sivaji
Analysis based on Degree of Polymerization (DP) value is assumed to provide reliable regarding insulation condition. However, due to the invasive nature of testing, DP value based-analysis is not feasible in practical cases as it requires a paper sample from the in-service unit. Here, an attempt is made to develop a methodology to predict DP value based on non-invasive testing of oil-paper insulation. In this paper, it is found that DP value maintains a well-known relation with interfacial charge (estimated using Polarization Depolarization Current data) as both these parameters are related to the cellulosic condition. The proposed method successfully applied on various laboratory prepared samples containing different moisture content.
Alternate fuel
(National Conference on Energy, Environment and Sustainable Shipping (NCESS), 21-22 December 2020, 2020-12-22) Hare, Ram Hare
As the world moves towards greener solutions for reduction in pollution by any source, the transportation industry will be greatly affected and hence major changes are taking place throughout. From automobiles, logistics, aviation and each and every machine in the supply chain is looking to cut down the emissions. Shipping contributes to 3% of the world’s total manmade carbon emissions. Around the world, air pollution is causing serious health problems and premature death, and local air pollution will be subject to tougher regulations over the coming years. Reducing emissions to air and introducing new propulsion technologies are key challenges for the worldwide transport sector, including shipping. The world’s future fleet will have to rely on a broader range of fuels, propulsion solutions and energy efficiency measures. All alternative fuel options have benefits and challenges. This guidance paper provides an introduction to alternative fuels and technology solutions. It includes an overview of selected alternative ship fuels – LNG, LPG, methanol, biofuel and hydrogen – as well as emerging technologies such as batteries, fuel cell systems and wind-assisted propulsion. The objectives of the paper are to provide decision support for investment in ships for the upcoming period. The paper focuses on technical parameters and limitations without accounting for local market conditions, considerations and incentive schemes which may have a significant impact on competitiveness and the uptake of alternative fuels and technologies. Marine fuel currently contributes approximately 3 per cent to global man-made CO2 emissions. Most seagoing ships are still using heavy fuel oil (HFO) or marine gas oil (MGO), with a maximum sulphur limit of 3.5 per cent (mass) in force for HFO and 0.1 per cent (mass) for low- sulphur MGO. Looking at the future with the IMO 2020 low-sulphur standards and upcoming CO2 emission regulation regime in mind, the share of conventional oil-based ship fuels will drop and the share of alternative fuels will grow. Prerequisites for introducing a new fuel include availability of sufficient production and distribution facilities as well as an adequate bunkering infrastructure. In addition, new fuels in many cases require extensive on- board modifications and a reversal to a conventional system is complex and costly.
Effect of charge accumulated at oil-paper interface on zero of transfer function formulated using classical debye model parameters
(IEEE, 2017-11) Mishra, Deepak; Pradhan, Arpan Kumar; Baral, Arijit; Haque, Nasirul; Chakravorti, Sivaji
PDC measurement and analysis is one of widely used tool for reliable diagnosis of power transformer insulation. In different reported methods of analysis it is considered that polarization current is composed of the current due to dipole movement and conduction current. Similarly the depolarization current is assumed to be composed of relaxation of dipoles. However when the dc conduction effect is removed from polarization current it is found the resulting current is not similar to the measured depolarization current. This deviation in both the currents show the presence of nonlinearity in the system. This nonlinearity arises due to migration of trapped charges that reside at the interfacial region of oil-paper insulation. The present paper shows the effect of such free charge on some important performance parameters like paper moisture and zero of Transfer Function of Classical Debye Model.
Effect of frequency on plasma electrolytic oxidation of zirconium in pulsed unipolar mode
(IOP Conf. Series: Materials Science and Engineering, 2019) Parfenov, E. V.; Mukaeva, V. R.; Farrakhov, R. G.; Saikiran, A.; Hariprasad, S.; Manoj, P.; Lokesh, E.; Rameshbabu, N.
Using the method of in situ impedance spectroscopy, an optimization of plasma electrolytic oxidation (PEO) was performed, and the influence of the pulse frequency was evaluated for the coating of Zr-1Nb alloy. It was shown that the in situ impedance modulus decreased with increasing the pulse frequency in a pulsed unipolar mode. Also, the protective properties of the coating improved with frequency; this was attributed to the increase in the uniform distribution of the microdischarges over the sample surface. As a result, the optimal frequency range of PEO was justified based on the impedance spectroscopy studies.
Effect of interfacial charge on parameters considered for insulation diagnosis of power transformer
(IEEE, 2017-12-02) Mishra, Deepak; Baral, Arijit; Pradhan, Arpan Kumar; Haque, Nasirul; Chakravorti, Sivaji
Out of various analysis methods available Polarization Depolarization Current (PDC) measurement is extensively used for monitoring of oil-paper insulation health. In such case, Classical Debye Model (CDM) is used for analysis of recorded PDC data. CDM has limited capacity to simulate the effect of interfacial charge. Due to this interfacial charge, nonlinearity arises in the system which adversely affects the insulation. Conductivity difference between oil and paper is the main reason behind this interfacial charge which creates nonlinearity in system. In the present work, the effect of interfacial charge is analyzed on some of the performance parameters used for diagnosis of insulation like peak value of return voltage spectrum and paper conductivity.
Effect of measurement temperature of insulation poles used for assessment of oil-paper insulation
(IEEE, 2018-12-07) Verma, R.; Mishra, Deepak; Baral, Arijit; Chakravorti, Sivaji
Analysis of Polarization-depolarization current (PDC) data is a popular technique used for assessing condition of oil-paper insulation. Oil-paper insulation deteriorates with aging during the operational life of the power equipment. In order to get information regarding the insulation condition; different performance parameters are used which can be estimated from PDC data. These parameters include paper moisture (%pm), Dissipation factor (%tanδ) and paper conductivity (σ paper ). In addition to these parameters, insulation poles can also be used for insulation diagnosis. Recently, it has gained popularity in field of insulation diagnosis as it does not depend on physical geometry of insulation. In this paper, the effect of measurement temperature on insulation poles has been analysed. Also, an attempt has been made to establish a relation between insulation poles and other insulation sensitive parameters such as %pm, σ paper and %tan δ.
Effect of measurement temperature on interfacial charge freed from deep traps located at the interface of oil-paper insulation
(IEEE, 2018-12-07) Dey, Debangshu; Sarkar, A.; Pal, Sayantan; Kumar, A.; Mishra, Deepak; Baral, Arijit; Haque, Nasirul; Chakravorti, Sivaji
Accumulation of interfacial charge creates local field distortion during insulation response measurement. Furthermore, such localized field enhancement affects the interaction between polar compounds present within oil-paper insulation and in turn affects its aging process. By getting sufficient trap energy (normally by thermal oscillation) these trapped charges dislocate from their locations and contribute in depolarization current. These interfacial charges include charges dislocated from shallow and deep sites at interfacial region. The charge residing at deep locations takes more time to dislodge themselves compared to charge residing at shallow sites. As dipole present in cellulose has large relaxation time, there might be some relation between deep charge and paper insulation sensitive parameters. In this work, effects of temperature on deep traps are analyzed. Results reported in this paper shows that magnitude of charge freed from deep locations maintains a correlation with measurement temperature and paper conductivity.
Estimation of performance parameters using charge freed from deep traps located at interfacial region of oil-paper insulation
(IEEE, 2019-11-21) Mishra, Deepak; Verma, R.; Baral, Arijit; Haque, Nasirul; Chakravorti, Sivaji
De-trapped charge dislodged from interfacial region of oil-paper insulation can be used as an effective insulation sensitive parameter. Over time, various physiochemical reactions takes place at interfacial region and consequently results in the formation of different trap sites (deep and shallow). Charges which resides at these traps sites are de- trapped after gaining sufficient energy. In present analysis, it is found that charge dislocated from deep traps maintains some specific type of relationship with different insulation sensitive parameters. Before using de-trapped (dislodge from deep traps) as an effective insulation sensitive parameter the effect of geometry must be reduced, as amount of de-trapped charge depends on the area of interfacial region which is not identical for all units. Result presented in this paper shows that use of geometric capacitance for normalization purposes significantly reduces the effects of insulation physical dimensions on de- trapped charge. The capability of deep charge (normalized using dc insulation resistance and geometrical capacitance) is also compared in the present work.
Feasibility of using normalized de-trapped charge for diagnosis of power transformer insulation
(IEEE, 2018-10-07) Mishra, Deepak; Baral, Arijit; Haque, Nasirul; Chakravorti, Sivaji
In order to use de-trapped interfacial charge as a performance parameter for diagnosis, it is necessary to reduce the influence of insulation geometry. Available literature shows that this can be done by considering dc insulation resistance R 0 as the normalization factor. Such normalization may not be always practically feasible as information regarding R 0 requires measurement of temperature sensitive low amplitude current. In this paper it is shown that geometric capacitance C 0 (instead of R 0 ) can be used as an effective normalization parameter to reduce effect of insulation geometry. Effect of normalizing freed interfacial charge using C 0 and R 0 and its subsequent effect on insulation diagnosis are presented in this paper.
Impact of Tamarindus Indica biodiesel blends on performance and exhaustemissions characteristics of light duty compression ignitionengine
(Materials Today: Proceedings, 2021) Jayashri N Nair; Satyanarayana Murthy, Y.V.V.
Tamarind (Tamarindus Indica) is an integral part of South Indian cuisine. Its pulp is used to add sourness to southIndian curries. However tamarind seeds which are having a considerable amount of lipid in it are thrown away. Ourmain objective is to produce Tamarind biodiesel (TB) from tamarind seed oil and investigate its effect onperformance and exhaust emissionsof CI engine. Oil was extracted from Tamarind seeds and was converted to biodiesel by transesterification process with NaOH as catalyst. Tests were performed using TB5, TB10, TB15 blendswith 1500 rpm rated speed and compression ratio of18. The performance test results revealed that BTE of B15 wasgreater in comparison to other blends as well as diesel . However BSFC for TB blends were greater compared to neat diesel . Considerable reductions in exhaust emissions were observed with TB blends. TB10 showed apical reductionof 27% in CO and 15% reduction in smoke. TB5 showed 25% HC reduction followed by TB10 with 19.25% reductions.TB15 showed 19.36% of highest NOx reduction followed by TB10 with 10.7% NOx reduction. TB10 proved to giveoptimum test results for performance and emissions. From the results it can be concluded that TB can be consideredas a viable option for biodiesels.
Introduction to natural gas: A comparative study of its storage, fuel costs and emissions for a harbor tug
(Society of Naval Architects & Marine Engineers, 2013-11-08) Eswara, Arun Kishore; Misra, S. C.; Ramesh, U. S.
This paper discusses the science of natural gas, its composition and ways to determine and coherently express its physical and chemical properties. Pricing of natural gas is shown with regard to weight and energy. A 60 Ton harbor tug employing either a set of constant rpm engines for CPP operation, or a set of variable rpm engines for FPP operation, with a standard load profile is made the basis for discussion. Advantage of evaluating thermal efficiency of gas engines relative to the higher heating value of natural gas, as against its lower heating value is explained. A compendium of storage options and the resulting endurance with the use of natural gas forms such as liquified gas (LNG), compressed gas (CNG) and adsorbed gas (ANG) is presented. Steps to ascertain fuel consumption of the gas engines operated according to the load profile and an approach to evaluate and relate the quantities of LNG, CNG and ANG is shown. Fuel costs and emissions from the tug operation using natural gas as fuel are evaluated per month and compared with diesel and residual fuels. Green House Gas emissions as a summation of emission constituents from the natural gas fuelled tug operation is detailed, and its need emphasized. The concepts of useful work done, emission efficiency parameter and energy efficiency parameter, which may be helpful in the design of harbor tugs and similar service vessels are proposed. The emission efficiency parameter is evaluated and analyzed for the 60 ton harbor tug.
Machine learning methods for marine systems
(IOP Conference Series: Materials Science and Engineering, 2021) Thangalakshmi, S.; Sivasami, K.
Automation plays a key role in shipping industry and aims towards minimal operating staff. However, the effective automation relies on effective controlling at various levels starting from shipbuilding to navigation. The industry is currently focussing on autonomous shipping which actually requires precise controlling. Although many conventional methods are available for control and automation with regard to automation, Artificial Intelligence Schemes (AIS) are widely attracting the maritime sector because of their benefits. The AIS along with fuzzy logic systems are offering promising results. The emerging use of AIS in a variety of maritime applications can act as a reference wpoint for new researchers. This paper aims to conduct a valid AIS study and to examine the various machine learning approaches used in various maritime applications. It is possible to achieve complete automation in the shipping industry by implementing a related technique.
Numerical computation of Boil off Rate (BoR) in shipboard LNG tanks
(IOP Publishing, 2022) Eswara, Arun Kishore; Sandilya, P.
Natural gas is an environment-friendly fuel and a raw material for many chemicals. Its offshore transport is economical when the gas is transported in liquefied form as Liquefied Natural Gas (LNG) over distances (exceeding 2000 kilometers) by sea. LNG is stored at near-atmospheric pressure and about 112 K in these tanks. Heat inleak from the ambient into the stored LNG causes considerable boil-off of the LNG due to low latent heat of vaporization of LNG. Boil off Gas (BoG) generation should be reduced to minimize the loss of LNG as well as environmental pollution. Determination of the boil-off rate (BoR) poses a challenge because it involves interplay of multitude of phenomena and considerations, like liquid sloshing that is likely to generate heat and increases the interfacial area between the liquid and the ullage, variation in LNG composition due to BoG generation, and thermal stratification. In this paper we present a numerical analysis of the BoG generation, including some of the effects just mentioned. A model including transport phenomena based-equations and thermodynamic phase relations has been developed for this purpose.The simulation results would help in carrying out more in depth study of BoG generation that is useful in the design and operation of the prismatic membrane tanks.
Performance evaluation : anti-windup two-loop PID controller for rotary single inverted pendulum
(IEEE, 2021-11-11) Pandey, Sandeep; Dwivedi, Prakash; Mishra, Deepak
In this paper, two loop Anti-windup PID controller is designed for Set-point tracking of Rotating arm and balancing vertical position of Pendulum of Rotary Single Inverted Pendulum. Controller ((feedback)) gains are obtained via pole placement and tuned by using the LQR technique. Comparative analysis of observer based pole placement controller, LQR and two-loop Anti-windup PID controller are experimentally illustrated. Steady-state error persists during the operation of two loop PD controller. In order to reduce this steady state error, integral term is added in controller. Due to violation of voltage constraints, an undesirable phenomena known as integral windup occurs. To overcome integral windup, Anti-windup technique (conditional integration) is used with two loop PID controller. Experimental result shows that proposed two loop Anti-windup PID controller gives better set-point tracking and a minimum steady-state error as compared to other controllers.
Prediction of manoeuvring behaviour of an offshore supply vessel by using simulation program
(Proceedings of MARTEC 2010 The International Conference on Marine Technology, 2010-12) Mohd Noor, Che Wan.; Muzathik, Abdul Majeed.; Wan Nik, Wan Mohd Norsani.; Ahmad, Mohammad Fadhli.; Samo, Khalid.; Balaji, Rajoo.
Manoeuvring ability of Offshore Supply Vessel (OSV) is a very critical aspect. An early prediction of vessel behaviour will definitely help to improve upon the design. The regular methods available for manoeuvring prediction such as free running model test, captive model test etc., are found to be expensive and time consuming. As an alternative, the current approach tries a numerical simulation method with parameters determined from a database. This study presents the manoeuvring prediction of an OSV which includes the development of time domain simulation program by using Matlab Simulink software. Three degrees of freedom were considered and applying the Newtonian laws, the equations of motion were framed. Further, forces on hull, forces and moments induced by propeller and rudder were also taken into reckoning. Results were obtained with inputs of vessel speeds, engine revolutions etc. Validation of the prediction results was also carried out by comparing the results with full-scale sea trial data. The prediction results show a good agreement with the sea trial data. Applying approximate numerical formula for manoeuvring prediction is seen to be a reliable and economic prediction tool at early design stages of such vessels.
Real time monitoring and controlling of marine sewage treatment plant effluent
(2022-02) Prasanna Kumar, R.; Ajantha Devi, V.
As on date around 56,000 vessels are moving in the World shipping fleet and it is growing every day. All these vessels were manned by seafarers who spend on an average of 6 months on-board. Their continuous stay onboard required the basic hotel service such as food, climate controlled Accommodation and all lavatory facilities. On top of this thousands of passenger ferries and cruise liners floating on the oceans also providing similar facilities for nature-calls of passengers. Discharge of these wastes from sewage system affects the marine environment, particularly in the confined water bodies similar to Baltic sea. One of the important requirements as per MARPOL (International conventions for the prevention of Pollution from ships,1973) by IMO is maintaining sewage treatment plant (STP) onboard[1]. This part has been specified in detail as ANNEX-IV – Prevention of Pollution by Sewage from ships[1]. Standards for Sewage treatment plant placed on-board is evaluated basis on the contents in the effluent from the plant after all processes completed. This evaluation is not performed on every STP fitted in so many numbers of vessels in service today. As a part of pre- building exercise STPs were chosen from list of type approved systems available. This type approval is issued by marine administrators by sample evaluation of one of the plant in the factory environment. This paper proposed the model STP in which the data from Real time monitoring the contents in the effluent can be used to regulate the air supplied to the plant. Different sensors such as microorganism detector, PH prob, Phosphorous sensor and Nitrogen detector of instant results types used for this purpose. To regulate the supplied air, frequency controlled motor is used in the supply–air Fan. This regulation of air will reduce the energy requirement of the overall process. Added with the regulation of air supply, real-time control on feed rate of dosing pump optimize the chemical use in the plant. Nitrogen and Phosphorus contents continues measurements and flowmeter readings from inlet and outlet of the plant ensure the effective performance of Full treatment module. This proposed model plant will be an energy efficient and real-time compliance to the international limitations stated in MARPOL.
Sensorless field oriented control of AC induction motor using PI, PD & PID controllers
(IEEE, 2022-11-20) Antony, Nikhil John; Mishra, Deepak; Parveen, Shabnam
With the Field-Oriented Control (FOC) vector approach, the control of the induction motor behaves similar to that of a separately excited dc motor. The torque and flux components in the d-q rotating reference frame can be independently controlled with the help of unit vectors. The main focus of the present work is to show the effective utilization and feasibility of field-oriented control of AC induction motors using PI, PD, and PID controllers without using any physical sensors and using observers. The speed, torque, and position in this scheme are estimated, analyzed, and simulated with the help of a motor control block-set in MATLAB/Simulink for a (10HP, squirrel cage induction motor) to a VSI using the SVPWM for effective modulation.
Some statistical relationships among dredger particulars observed in the Indian dredging fleet
(The Royal Institution of Naval Architects, 2015-12-10) Eswara, Arun Kishore; Ramesh, U. S.
Cutter suction dredgers (CSD), Trailing suction hopper dredgers (TSHD) and Grab dredgers form 88% of the total Indian fleet size, respectively in the order of individual share. Indian yards have achieved 90% indigenization in design and construction of grab hopper dredgers. However, there is a techno-economic backlog in India to manufacture some vital components for CSDs and TSHDs and companies are increasingly looking to buy foreign made dredgers at a high price. Dredging demand in India at ports and in navigable inland water ways is set to grow with the encouragement for water transport. Ministry of Shipping, Govt. of India has sponsored studies at Indian Maritime University-Visakhapatnam (formerly, NSDRC) for indigenization of dredger design and manufacture. The present paper aims to illustrate the existing dredger fleet of India and bring out some interesting correlations that aid the design of dredgers. Dredgers are built for a specific function. Due to this design objective, they differ from other marine vessels on the aspects of principle particulars, hopper capacities, powering and other functional data such as cutter power for CSD and dredge pumps power etc. The identified correlations among such parameters observed from the Indian dredging fleet are discussed. Certain ratios among the main dimensions for a TSHD such as length/breadth, breadth/dredge depth and breadth/draught, also known as ship ratios, are a key to dredger design and are known to vary with market conditions or time. They indicate design trends for future dredgers and require to be kept updated.
Study of flow in the test section of a circulating water channel by varying the honey comb cross-section
(Indian Maritime University, Visakhapatnam, 2019) Kiran George, Varghese; Vinay Gopi, Nair; Godey, Avinash; Sunil Kumar, PG.
The Circulation Water Channel (CWC) is a research facility available at Indian Maritime University, Visakhapatnam Campus. The investigation of a flow, in different configurations of the CWC set up, for obtaining a required flow velocity in the test section, is complex. To study the flow, a physical model of the CWC, with different configurations, should be made, which in overall is a complicated and time-consuming exercise. But this difficulty can be overcome through using Computational Fluid Dynamics (CFD) analysis, as in this study, where a CFD analysis is done using ‘STAR-CCM+’ software. A CFD model of the existing CWC [corresponding to the 1:4 scale setup at IMUV], is first made, and its validity is checked, by comparing the results of the CFD analysis, against those results obtained from the experimental analysis. The test section is the area in the CWC, or its CFD model, where the experimental activities are carried out. It is important to have a smooth streamlined flow in the test section, and to ensure this, a honeycomb structure is placed such that the flow enters the test section through the structure. The optimum honeycomb structure, which produces a smooth flow in the test section of a CWC, is found out, by conducting analyses for different shapes - i.e. for shapes ranging from rectangular to hexagonal and also for different inlet velocities