http://localhost:8081/jspui/handle/123456789/28 Wed, 21 Oct 2026 04:35:54 GMT 2026-10-21T04:35:54Z http://localhost:8081/jspui/handle/123456789/21746 Title: State and Line Parameter Estimation in Three Phase Distribution System Authors: Alam, Mohd Tauhid Abstract: The necessity for safe and stable techniques for monitoring, control, and operation of a distribution system has become increasingly important in the last few decades. The load flow analysis and state estimation are the most crucial components in monitoring and operational studies. Moreover, load flowstudies and state estimation are distinct methodologies utilized in transmission/ distribution system. The load flowanalysis is a method that gives a deterministic study of the network under steady-state conditions. In contrast, state estimation provides the most accurate estimates of the real operating condition of the distribution network while accounting for the presence of noisy as well as bad measurements. The architecture and radial topology of the distribution network differ significantly from those of the transmission network. Because of unbalanced nature of the distribution system, the state estimation (SE) algorithm originally intended for the transmission system needs to be suitably modified for the distribution system. The distribution system is usually unbalanced in nature configuration and has short feeder sections with higher R/X ratio resulting in higher I2R losses. Unlike transmission network, the distribution system is characterized by its vast geographical spread and limited realtime measurement which can lead to significant observability challenge. Despite the recent implementation of advanced metering infrastructure (AMI), the installation of smart meters at all nodes is not economically feasible. State estimation technique usually assumes that the line parameters values of a distribution network are exactly known. Nevertheless, this assertion is inaccurate, as the operating values of the line parameter can vary over a period of time due to factors such as ambient temperature, and conductor degradation. Seasonal fluctuations in soil resistivity and temperature are critical environmental factors that substantially influence the values of line parameters. In addition, human errors such as misreading, inaccuracies in the database input, and various measurement methods can lead to variations in the network parameters. Fri, 01 Aug 2025 00:00:00 GMT http://localhost:8081/jspui/handle/123456789/21746 2025-08-01T00:00:00Z http://localhost:8081/jspui/handle/123456789/20486 Title: HEALTH MONITORING AND IDENTIFICATION OF INDUCTION MOTOR FAULTS BASED ON CURRENT AND VIBRATION SIGNALS Authors: Kumar, Rajeev Abstract: Induction motors, especially three-phase induction motors, play an important role in various industries owing to their advantages over other electrical machines due to their reliability and safe operation. However, if any faults or failures occur in the motor, it can lead to increased breakdown time and substantially generate huge losses in terms of revenue and maintenance. Therefore, an early fault detection scheme is needed for prior maintenance of these motors. In the current scenario, the demand for health monitoring of induction motors is growing with the objective of reducing their operational costs, enhancing their operational reliability and providing better service to customers. In recent trends, various monitoring methods are being used to investigate fault conditions in induction motors. On the basis of these methods, the health monitoring schemes of induction motors are categorised into two major areas such as feature extraction based analysis and knowledge based analysis. For real time health monitoring, signal processing based feature extraction methods are being used. The incipient faults are diagnosed by extracting signatures from measured signals such as vibration signal, noise signal, current and voltage signal etc. The knowledge based approaches are quite popular among researchers, which are being developed by using artificial intelligence, deep learning and machine learning algorithms to detect the faults most accurately at early stages. The research presented in this thesis is primarily focused on signal processing analysis, using machine learning algorithms to identify stator winding inter-turn faults and ball bearing faults. To identify these faults, experimental setups are developed for each fault separately that are capable of measuring both current and vibration signals by conducting experiments in the laboratory. The subsequent analysis is carried out using MATLAB and Python programming. These early stage incipient faults are analysed utilising through current and vibration signals with various signal processing techniques such as Fast Fourier Transform (FFT), Park’s Vector Magnitude Analysis (PVM), Signal Envelope Identification Analysis (SEI) and Zero Crossing Time Detection (ZCT). Wed, 01 May 2024 00:00:00 GMT http://localhost:8081/jspui/handle/123456789/20486 2024-05-01T00:00:00Z http://localhost:8081/jspui/handle/123456789/20478 Title: STATE ESTIMATION AND UNCERTAIN POWER FLOW OF ISLANDED AC AND HYBRID AC/DC MICROGRIDS Authors: Surendra, Kundukuri Abstract: The Distribution System (DS) has gained significant attention in power system studies due to the integration of innovative technologies such as distributed generations from renewable energy sources (RES), internet and communication technologies (ICT), advanced monitoring technologies (AMI, smart meters), and customer participation for demand side management. The power system studies can be broadly categorized into operational and planning studies. State Estimation (SE) and Power Flow (PF) are the most critical components in operational and planning studies. These two functions (SE and PF) are crucial as other operational and planning functions heavily rely on the results of SE and PF, such as fault detection, load balancing, and system stability analysis. The generation from renewable sources (RES) is increasing rapidly to meet the global goals of carbon neutrality, sustainable energy for the future, and eco-friendly mobility solutions. The RES integrated into DS is considered distributed generations (DGs), and they increase the efficiency of DS through reduced transmission losses. Further, the smaller size and less commissioning time reduce the capital cost of DS. The DGs increase the DS sustainability and reliability through Microgrid (MG) structures. MG is a portion of DS with a group of DGs, loads, and storage systems operating as a single control entity. Microgrids (MGs) are classified into AC, DC, and Hybrid AC/DC based on their distribution nature. These AC, DC, and hybrid AC/DC MGs can operate in two distinct modes: grid-connected and islanded. In the former, with the assumption of an infinite bus, the DGs in the DS aim to maximize the utilization of RES, and the intermittency of renewable DGs can be managed by the primary grid. However, in the face of natural calamities, grid-side faults, power quality issues, or cyber-attacks, the AC, DC, and hybrid AC/DC MGs switch to islanded mode. In this scenario, the primary objective is to find the equilibrium operating point to supply the critical loads through RES or conventional non-renewable generations. This independent operation of MGs not only enhances the reliability of the DS but also ensures the supply of power to customers even in the absence of the grid. Due to the absence of a slack bus for islanded AC, DC, and hybrid AC/DC MGs, the generation output from the DGs depends on the load requirements, with the load being shared proportionally to their maximum capacity. This approach is simple and cost-effective because it does not require any communication systems, which are prone to single-point failures. The amount of power generated by each DG in islanded AC MG (IMG) and islanded AC/DC hybrid MG (IHMG) is calculated using the droop characteristics of DGs. This thesis focuses on developing State Estimation (SE) and Uncertain Power Flow (UPF) models for Islanded AC Microgrids (IMG) and Islanded Hybrid AC/DC Microgrids (IHMG). Sat, 01 Jun 2024 00:00:00 GMT http://localhost:8081/jspui/handle/123456789/20478 2024-06-01T00:00:00Z http://localhost:8081/jspui/handle/123456789/20477 Title: ANALYSIS AND DEVELOPMENT OF SINGLE STAGE SOLAR PV INVERTER SYSTEM Authors: Jaga, Om Prakash Abstract: T HEgrowingelectricitydemandisrisingduetotherisingpopulationanddepletionof non-renewableenergysources,rapidclimatechangeandglobalwarmingareamongthe major threats to today’sworld. Renewable energy sources (RESs) such as solar photovoltaic(PV)havebecomeanalternativeoptionforrisingenergydemands.Solarenergy iscountedamongsteasily availableRESs.One ofthemajoradvantages ofsolarPVis thatitis independentofend-userlocation.Inthecaseofnon-electrifiedremote areas,itbecomesmore economical to use solar photovoltaic (PV) based power generation compared to the conventional grid-connectedsystem.Critical loadapplications suchashealthcarefacilities, informationtechnology-enabledservices, telecommunicationnetworkingandelectronicloads likecomputersrequireanuninterruptedpowersupply.ThePVelectricityisnotaccessibleat night or during rainyweather.Grid-tied solar energyconversion system(SECS) delivers electricitytoessentialloads.However,gridoutagesarerelativelyfrequentinIndia,loweringthe dependabilityofgrid-tiedSECS.Thebatteryenergystorage(BES)systemcanbeinterfaced with/withoutabidirectionalDC/DCconverterattheDClinktoimprovegrid-tiedSEC system reliability.TheSECsystemcanbeclassifiedintotwomaincategories: two-stageandsingle stage. GridoutagesisfrequentandverycommoninIndia.Therefore, theutilitymainsmustbe isolatedseamlesslysoasnot toaffect critical loads and theoccurrenceof voltage/current sag/swellshouldnotaffectsystemperformance.Unintentionalgrid-outagemayoccurdueto theutilitymainsfailure,circuitbreakeropening,orhumanmistake.Henceforth,anislanding detection(ID)/re-synchronizationcontroller is requiredtobemadeoperational. Ingrid-tied mode, theACmainsmaintain the amplitude and frequencyof gridvoltage.However, in islandedmode, it isessential tomaintainloadvoltageamplitude, frequencyandTHDwithin thelimits inlinewithIEEE-519.Non-linearloadsconnectedatthepointofcommoncoupling pollute theutilitymainsby injectingharmonics.Harmonics in thegridcurrentmaycause overheating, short lifespans, andmalfunctioningof appliances.Thepower qualityofgrid currentistobesustainedwithinalimitinaccordancewithIEEE-519.Therefore,acontrolled single-phaseVSCalsooperatesasaDSTATCOMtocatertotheload'sreactivepowerdemand. Inthisthesiswork,dual-modetwo-stageandsingle-stagemultifunctional self-reliantgrid interactive single-phase SEC-BES systems are designed, controlled, simulated and implemented.Theprimegoalof thisworkis tosupplycontinuouspower tothecritical load i regardlessof theavailabilityof theACmains. Insurpluspowermode(SPM), thegenerated power fromthePVishigher thanthedemandpower fromthecritical loads.Therefore, the surpluspowerofthePVisusedtochargetheBESsystemandtheremainingactivepoweris injectedintotheACmains. Indeficitpowermode(DPM), thegeneratedpowerof thePVis lesserthanthedemandpowerofthe criticalloads.Insuchacase,thebalancepowerissupplied either fromtheACmainsor theBESsystem,whichdependsontheavailabilityof theAC mains. Thisworkmainlyclassifies the grid-tiedSEC-BES systemcontrol scheme into three categories.Inthefirstcategory,aPI-Leadcompensator-baseddual-loopandmodelpredictive controlschemesfor abidirectional DC/DCconverteraredesigned,simulatedandimplemented tocontrol theDCbusvoltageandBESsystemcharging/dischargingcurrentundervarious operatingmodes.Inaddition,thepresentedDC/DCconvertercontrolschemealsoensuresthe extractofmaximumpowerfromthePVarray.Moreover,astate-of-chargecontrollerwitha bidirectionalDC/DCconverterprotectstheBESsystemfromdeep-discharging/overcharging. ThestabilityanalysisofabidirectionalDC/DCconverterhasbeenpresentedthoroughlyboth for the PI-lead compensator and model predictive controller. Designing the PI-Lead compensator parametersbasedon systemstabilityconstrained tooperate thebidirectional DC/DCconverter inastableregionundervariousoperatingconditionsbecomes important. Therefore, thedual-loopPI-Leadcontroller parametersaredesignedbasedon the stability constraintsinthefrequency domain. Thestabilityanalysis ofabidirectionalDC/DCconverter for amodel predictive controller is analysed in the Z-domain. The Jacobianmatrix is constructedusingthestatevariableequationsofabidirectionalDC/DCconverter.TheJacobian matrixeigenvaluesdeterminethestabilityofabidirectionalDC/DCconverter. Ifeigenvalues liesinsidetheunitecirclethentheDC/DC converteroperates inastableregion.Otherwise,the systemisunstable. ThebidirectionalDC/DCconverterparameters (DCbus capacitor and converter inductance)andtheweightingfactorforamodelpredictivecontrolleraredesigned basedonbidirectional DC/DCconverteroperation ina stability region. Sat, 01 Jun 2024 00:00:00 GMT http://localhost:8081/jspui/handle/123456789/20477 2024-06-01T00:00:00Z