Conference Proceedings

Permanent URI for this collectionhttps://dspacenew8-imu.refread.com/handle/123456789/1718

Browse

Now showing 1 - 19 of 19

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.
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 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.
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.
Is outsourcing the Panacea? a discourse on the sustainability of Indian ports a case of Jawaharlal Nehru port trust
(International Association of Maritime Universities, Alexandria, Egypt, 2021-10-27) Mitra, T; Pattanaik, K. M.
The discourse on sustainable transportation illuminates the fact that port competitiveness and efficiency gains are two major pillars of blue economy in a world which is much integrated than in the past. However, most literature on port efficiency measurement undermine the very eco system of a port. Port eco system is complex interconnected web of network which requires collaborative involvement of spate of stakeholders such as CFS, Agents, ICDs, Transportation companies, to mention a few. Understanding such network and their holistic potential impact on the efficiency of port performance is scarcely addressed in the context of larger dialogue on port efficiency. Such an analysis is paramount when deeper levels of economic integration and spatially competitive ports are considered to be co joint twins. Further, efficiency gains of ports have received much academic attention in view of total quality management which focuses on customer delight and thus customer retention. It is this regard; the present paper tries to make an infant endeavour in terms of measuring terminal efficiency with respect to the turnaround time which would include export cycle time and import cycle time of CFS (a potential outsourcing activity of a port). Such a step in efficiency measurement of ports is scanty in Indian scenario. A case of Jawaharlal Nehru Port Trust is referred as a case in point.
Linking Leadership Integrity - Depression, Anxiety and Stress (DAS) among Sailing Indian Marine Engineers During Covid-19
(Barcelona School of Nautical Studies, Barcelona, 2024-06-05) Mitra, Toorban; Pattanaik, Krushna Mohan
Modern-day leadership demands competencies to embrace challenges and uncertainties as a part of a working career. Uncertainties bring in many unknown outcomes and a loss of direction to any team. This is much acknowledged when the unknown outcomes are affecting the team spirit and, in turn, organisational sustainability. Leadership integrity is a watershed to handle such uncertainties with positive outcomes. Like in any other business domain, uncertainties are part of the business in shipping. However, there are specific instances in the nature of COVID-19 that came with many challenges, like extended work contracts, no shore leaves, infrequent crew change, quarantine rules before sign-in, online surveys, etc. Such an uncertain and challenging work environment on board a ship (which itself is an organisation) results in anxiety, stress and depression. In this context, leadership integrity provides much-needed direction and can create a healthy work environment in any organisation. It is in this context that this paper tries to measure this hypothesis in an explorative study, particularly among active marine engineers who worked on board ships during the COVID-19 pandemic. Such knowledge facilitates the understanding of organisational behaviour during challenging times and provides a timely prescription for organisational success during uncertainties and challenging times with much significant focus on the integrity of leaders.
Logistics performance as facilitator to trade performance: An Indian perspective
(The International Maritime Transport and Logistics Conference "MARLOG 13", 2024-03-03) Dasgupta, Mrinal Kumar; Mitra, Toorban; Pattanaik, Krushna Mohan
With the growing realisation of the importance of global integration in the production and consumption value chain, the importance of maritime logistics and transportation facilitating international trade is profoundly recognised. Further, a proliferation of collaborative trade agreements among different trade partners is ascribed to play a significant role. However, such external dynamics and engagements in international trade would propel blue economic growth if backed by strong maritime logistics initiatives and establishment. In this context, deep routed challenges, particularly in the domestic maritime logistics sector in manufacturing hubs like India, could potentially hamper her comparative advantages in international trade. It is in this context that this paper comes as an intercession by analysing India’s Logistics Performance Index (LPI) and its impact on trade performance. Also, this paper provides a comparative analysis of India’s LPI with that of other trade competitors from South and East Asia and tries to find out challenging areas of maritime logistics for India and suggest the required policy prescription thereof. Such acknowledgement is a compulsion for a country like India when escalated uncertainties due to episodes of COVID-19, the Russia-Ukraine War, and dips in the business cycles of many countries that demanded green and resilient supply chain and logistics practices. The paper prescribes that domestic reforms to ease out challenges in Indian maritime logistics coupled with external engagements would provide a flat form for India to reap the optimal gains from international trade.
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.
Outsourcing of logistics and global competitiveness –A case study on Jawaharlal Nehru Port Trust
(Indian Maritime University and Academy of Maritime Education and Training, Chennai, 2019) Mitra, Toorban & Pattanaik, Krushna Mohan
With the emergence of global competitiveness in port sector, it is imperative that a port is not just operational but also effective in its service provision. Logistics performance, ceteris peribus, stimulates this effectiveness of a port significantly in terms of its performance. In this context it is illuminated that outsourcing of logistic activities and competitiveness of a port are co-habitants. In view of the present background set, the present study makes an intervention to explore performance of various outsourced stakeholders involved in logistic service provision for Jawharlal Nehru Port Trust (JNPT) which may include service provision of various Container Freight Stations (CFS), Inland Container Depots (ICD) and Logistic Operators under JNPT. Using secondary data collected from various stake holders to establish standard port operation indicators, this paper makes an endeavor to measure the comparative performance of each of these stakeholders which in turn would facilitate their respective macro operational impact on the effectiveness of JNPT to face growing global competitiveness in the coming times. As a follow up, strategic options are suggested for improvement and retention of competitive performance of outsourced stakeholders involved in logistics service provisions in JNPT’s operations.
Outsourcing of logistics and global competitiveness: a case study on Jawaharlal Nehru port trust
(MARINCO 2019, Indian Maritime University, Chennai, 2019-11-04) Mitra, T; Pattanaik, K. M.
With the emergence of global competitiveness in port sector, it is imperative that a port is not just operational but also effective in its service provision. Logistics performance, ceteris peribus, stimulates this effectiveness of a port significantly in terms of its performance. In this context it is illuminated that outsourcing of logistic activities and competitiveness of a port are co-habitants. In view of the present background set, the present study makes an intervention to explore performance of various outsourced stakeholders involved in logistic service provision for Jawharlal Nehru Port Trust (JNPT) which may include service provision of various Container Freight Stations (CFS), Inland Container Depots (ICD) and Logistic Operators under JNPT. Using secondary data collected from various stake holders to establish standard port operation indicators, this paper makes an endeavor to measure the comparative performance of each of these stakeholders which in turn would facilitate their respective macro operational impact on the effectiveness of JNPT to face growing global competitiveness in the coming times. As a follow up, strategic options are suggested for improvement and retention of competitive performance of outsourced stakeholders involved in logistics service provisions in JNPT’s operations.
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.
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.
The prospects of dredging and indigenization of dredger design
(Dredge India INAvation 2015 conference, 2015) Eswara, Arun Kishore; Ramesh, U. S.
The scope for dredging in India is potentially vast, looking at the prospects of development and maintenance of existing major ports, building new ports, offshore resources exploration, demand from navy and more interestingly the projects envisaged for national waterways. The capital dredging demand during 2012-2017 is about 639 million m3 and that of maintenance dredging during the same period is about 521 million m3. This requires the employment of substantial number of dredgers of varying capacities. The minor sector dredging demand of about 100 million m3, during the said period, offers additional opportunity for dredging. The modal shift of cargo to inland and coastal waterways offers bright prospects for a sustainable economic prosperity. The government encouragement for “Make in India” has brought in a lot of economic interest as well. This is an excellent period to target for indigenization of dredger manufacture. Locally manufactured dredgers not only reduce costs of dredging but also encourage business climate. Further, it will enable India to produce globally competitive world class dredgers. The present paper is written in this context of presenting our study1 encompassing the scope for dredging activity, identifying suitable types and capacities of dredgers for employment in India. The paper also touches upon the present shipbuilding infrastructure, dredger equipment manufacturers and a road map for indigenization. The paper concludes with forecasting future dredging demands, scope for native dredgers manufacture, identifying a particular target range for indigenization.