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ThesisItem Open Access Improvement of voltage profile in distribution system using compensating devices(G. B. Pant University of Agriculture and Technology, Pantnagar, 2022-10) Pandey, Kamal; Singh, SunilOptimal reactive power deployment in accordance with the statutory provisions of Indian Electricity Grid Codes is important for better performance of the system. Better voltage profile, lower losses, and improved efficiency are measures of distribution system quality. The aim is to keep the system operating smoothly with a better voltage profile at every node. A good distribution network is hence expected to improve overall efficiency of the system through loss minimization and power quality control. Due to the bidirectional nature of the present distribution system, DFACTS devices are gaining relevance almost everywhere for quick voltage management, power quality maintenance, and enhanced stability margins In this research work, a 33 bus distribution system of base 12.66 kV and 10 MVA is taken into consideration. After that, the improvement of voltage profile is discussed. By using load flow analysis, the values of unknown parameters are calculated. The impact of single and multiple D-STATCOM is investigated. The minimum voltage profile is improved to 0.9523 pu (5.18 % from base case) and 0.9780 pu (8.18 % from base case) from 0.9040 pu in single and multiple D-STATCOM cases respectively. The real and reactive power losses are reduced by 28.37 % and 27.55 % in single D-STATCOM case; while in the case of multiple D-STATCOM case, this reduction is 38.09 % and 37.02 % respectively. Overall, it is concluded that in this case, the D-STATCOM helps in improving the voltage profile by injecting a suitable amount of reactive power into the system.ThesisItem Open Access Analysis of the performance of different induction motors under various voltage sag conditions(G. B. Pant University of Agriculture and Technology, Pantnagar, 2022-10) Sati, Karan; Gupta, ShobhitVoltage sag is one of the primary concerns in power quality disturbance, even though there are several ways to characterize voltage sag, two basic characteristics i.e. sag magnitude and sag duration are the two most commonly used. Electromagnetic torque generated by an induction motor is directly proportional to the square of the voltage. Due to the wide use and popularity of induction motors, this thesis investigates the effect of voltage sag duration, loading conditions, and power rating on the performance of induction motors under different voltage sags at various points of sag initiation. In the MATLAB Simulink environment, simulations of two different rated induction motors under various voltage types of sags of magnitudes (0.2 pu,0.5 pu, and 0.8 pu) and duration 10 cycles (instantaneous sag) or sag of duration 1 sec (momentary sag) are performed. Results of the simulations have been compared based on torque peaks and current peaks. It has been found that the torque peak for an instantaneous sag is similar to the torque peak for a momentary sag for each type of voltage sags. Whereas current peaks were affected by the sag duration it has been found for momentary voltage sag of Type A, Type C, and Type D the magnitude of the current peak increases in comparison to instantaneous voltage sag. The effects of loading conditions and power rating are also investigated.ThesisItem Open Access Design and analysis of three phase active series compensator for power quality improvement in distribution system(G. B. Pant University of Agriculture and Technology, Pantnagar, 2022-08) Kousar Jan; Kousar Jan; Kousar Jan; Pathak, Geeta; Pathak, Geeta; Pathak, GeetaPower quality is one of the main issues in today's electrical distribution system because of the escalation in use of power electronic devices. Harmonics, voltage sag, voltage swell, power interruptions, and other problems with power quality have an impact on utility distribution networks and sensitive industrial loads. In this thesis, a three-phase DVR (Dynamic Voltage Restorer) model is developed in Matlab-Simulink to protect critical loads from voltage-related power quality problems. The detailed design of the primary system parameters, including the voltage source converter (VSC), the three-phase series injection transformer, the ripple filter (Rr, Cr), and the interfacing inductance (LT) is provided. The simulation of Synchronous Reference Frame Theory (SRFT), Instantaneous Reactive Power Theory (IRPT), Affine Projection (AP), and Affine Projection Like (APL-II) algorithm based three-phase DVR is performed and analysed under a number of source side voltage quality issues, including balanced voltage sag and swell, unbalanced voltage sag and swell, and voltage harmonic distortion. The voltage harmonic distortion is analysed for both lower and higher order harmonics. PI (Proportional Integral) controller is used to keep the DC-link voltage constant. The SPWM (Sinusoidal Pulse Width Modulation) technique is used to generate gate pulses for the VSC (Voltage Source Converter) of DVR. The comparison of stability, time response, convergence speed, and THD (Total Harmonic Distortion) for both lower and higher order harmonics is done thoroughly. These control algorithms use energy-minimized voltage compensation technique which makes the Dynamic Voltage Restorer self-supporting in nature i.e. only the capacitor is adequate at the DC-bus of the VSC, and no additional energy storage device is required.ThesisItem Open Access Modelling Li-ion batteries with distinct chemistries using advanced system identification based data driven techniques(G.B. Pant University of Agriculture and Technology, Pantnagar, District Udham Singh Nagar, Uttarakhand. PIN - 263145, 2022-08) Rawat, Shivani; Singh, RajivRecently Li-ion batteries have emerged as a potential candidate for reliable energy storage. This had been on the account of their high energy density and power as compared to their counterparts in addition to long life and improved charge-discharge cycles. Li-ion batteries are available in chemistries such as NCA, NMC, LFP, LCO, etc. Li-ion batteries being critical to EVs and other applications involving energy storage requirements need to be modelled accurately and precisely. This is essential for proper energy management by calculating the SOC, SOH, and RUL of the battery. Accurate models are necessary to be incorporated within the BMS handling the optimal regulation of the energy output from battery including the efficient charging. In this thesis work three different chemistries of Li-ion battery have been chosen for modelling using advanced data driven method called system identification. The selected chemistries of Li-ion batteries are NCA, NMC, and LFP. For each chemistry a linear Transfer function model and a nonlinear model Hamm- Wiener model has been realized using system identification approach also sometimes called experimental based modeling technique. A set of linear and nonlinear models are created using system identification technique. The mathematical metrics of the fit between the reference and simulated signals is used to choose the optimal and best model. In comparison to the linear model the nonlinear model was obtained to be more accurate for all the batteries. The accuracies achieved by the nonlinear model for NCA, NMC, and LFP are 94.15%, 92.23%, and 90.78% respectively. Hence, it can be concluded that the Hammwiener model being the best can be used effectively for representing a Li-ion battery in different applications using BMS.ThesisItem Open Access Evaluation and comparison of active cell balancing methods using energy storing elements(G.B. Pant University of Agriculture and Technology, Pantnagar, District Udham Singh Nagar, Uttarakhand. PIN - 263145, 2022-09) Panwar, Garima; Saxena, RaviIn recent years the popularity of using lithium-ion batteries for energy storage purposes has risen a lot. However, the range of lithium-ion batteries available in the market is very small and for higher power requirements a significant number of cells are to be connected in series and parallel combinations. But when the cells are connected in series the problem of imbalance arises among them. Over the time, imbalance causes cell deterioration and reduced efficiency, therefore cell balancing becomes necessary in order to make sure the safe and reliable operation of lithium-ion batteries. The functionality of cell balancing is integrated within a Battery Management System. Cell balancing can be done in two ways i.e., passive balancing and active balancing. In passive balancing the excess charge is dissipated through a resistive element until all the cells come in balance with each other and in active balancing the excess charge is redistributed from higher energy cell to lower energy cell by using an external energy storing element such as an inductor, capacitor etc. In this work, capacitor-based active cell balancing has been studied because they have a simpler controlling mechanism as well as their implementation costs are less. More specifically, in this work, the implementation and comparison of switched capacitor, double-tiered switched capacitor, and chain-structure switched capacitor based balancing techniques have been done. The modelling of these techniques has been done in MATLAB/ Simulink and results are obtained for a series combination of 4 number of lithium-ion cells having 3.7V and 2.6A ratings with initial SOC variation as 15% and 8%. The cells are considered to be balanced when the maximum SOC difference between them reaches 1%. The results show that the double-tiered balancing technique takes the least time to balance the cells as compared to the switched capacitor and double chain-structure based techniques.ThesisItem Open Access Comparison of various artificial neuron models for very short-term load forecasting(G.B. Pant University of Agriculture and Technology, Pantnagar, District Udham Singh Nagar, Uttarakhand. PIN - 263145, 2022-08) Joshi, Harsh; Yadav, AbhishekLoad forecasting has always been a crucial component of the operational and managerial aspect of efficient power system planning. Since there are several factors on which load forecasting depends, it becomes necessary to find out the level of impact these factors put on it. There are several techniques and models which can be used to forecast load on the basis of requirement such as- regression based model, fuzzy time series based model, support vector machine based model, and artificial neuron network based models etc. Artificial neural network (ANN) based models are considered as one of the popular methods for different levels of forecasting, hence used in the study. Data preparation is performed by transforming the historical electric load of Uttarakhand state adopting Max-Min normalization. The prepared data is partitioned into the categories of training and testing data for further application of the conventional and different multiplicative neuron models. The conventional ANN model having eight input nodes and one output neuron was evaluated with different combinations of activation functions. This model achieved the mean-square-error (MSE) of 0.0007. Among various multiplicative neuron models applied for VSTLF, the overall performance of QIFNM is found to be the best. The QIFNM having a single neuron achieved the MSE of 0.0020. As per, Akaike Information Criterion (AIC), all multiplicative neuron models performed better than the MLP based conventional ANN and QIFNM came out to be the best model among all. The performance analysis of these models revealed that a single multiplicative neuron can be used for VSTLF with better performance as per AIC than that of a network of several neurons of the conventional model.ThesisItem Open Access Analysis and harmonic reduction in different multi-pulse converter topologies(G.B. Pant University of Agriculture and Technology, Pantnagar, District Udham Singh Nagar, Uttarakhand. PIN - 263145, 2022-02) Chauhan, Gokul Singh; Singh, SunilPower electronics devises which are used by the power industry in the past two decades are increased. Which are the main source of harmonic in now a day. In this the simulate -pulse converters are developed in MATLAB/SIMULINK for improving power quality by reducing harmonics in ac main. We have also improved the power factor of input and ripple factor of dc output and analyzed the effect of source inductance on THD, ripple factor and input power factor. The simulation of 12-pulses, 18-pulses and 24-pulses multi-pulse is performed on MATLAB/SIMULINK for R, RL, RC and D.C. motor as load. The THD, ripple factor and input power factor are calculated for 12,18 and 24 multi pulse converters. The primary winding of the transformers is connected in zigzag, while the secondary windings of the transformer are connected to the converter. By choosing appropriate phase shift between the primary and secondary sides of the transformer the lower order harmonica can be eliminated in pair. so, a very high power quality voltage and current waveform can be synthesized. Comparison of THD (total harmonic distortion) in the input current, ripple in the output voltage and power factor of input side is done in this work. Now we can conclude that performance of uncontrolled converters is better than controlled converters. THD and ripple factor is improved as we go from lower pulse to higher pulse. 24-pulse is more economical and gives better results then 18-pulse converter.ThesisItem Open Access Analysis and harmonic reduction in different multi-pulse converter topologies(G. B. Pant University of Agriculture and Technology, Pantnagar, 2022-02) Chauhan, Gokul Singh; Singh, SunilPower electronics devises which are used by the power industry in the past two decades are increased. Which are the main source of harmonic in now a day. In this the simulate -pulse converters are developed in MATLAB/SIMULINK for improving power quality by reducing harmonics in ac main. We have also improved the power factor of input and ripple factor of dc output and analyzed the effect of source inductance on THD, ripple factor and input power factor. The simulation of 12-pulses, 18-pulses and 24-pulses multi-pulse is performed on MATLAB/SIMULINK for R, RL, RC and D.C. motor as load. The THD, ripple factor and input power factor are calculated for 12,18 and 24 multi pulse converters. The primary winding of the transformers is connected in zigzag, while the secondary windings of the transformer are connected to the converter. By choosing appropriate phase shift between the primary and secondary sides of the transformer the lower order harmonica can be eliminated in pair. so, a very high power quality voltage and current waveform can be synthesized. Comparison of THD (total harmonic distortion) in the input current, ripple in the output voltage and power factor of input side is done in this work. Now we can conclude that performance of uncontrolled converters is better than controlled converters. THD and ripple factor is improved as we go from lower pulse to higher pulse. 24-pulse is more economical and gives better results then 18-pulse converter.ThesisItem Open Access Implementation of control schemes on DSTATCOM to enhance power quality(G.B. Pant University of Agriculture and Technology, Pantnagar, District Udham Singh Nagar, Uttarakhand. PIN - 263145, 2022-02) Singh, Chandradeep; Pathak, GeetaPower quality issues have always been existing in the distribution system but nowadays these have become prevalent due to the increased use of power electronicsbased equipment for commercial and domestic purposes like computers, LCD/LED TVs, various lighting systems and electric drives, and domestic loads along with switched-mode power supplies, etc. which injects harmonic currents into the supply system and deteriorate the power quality. Power quality measures like power factor correction, voltage regulation, load balancing, and harmonic elimination can be maintained and fixed using Distribution Static Compensator (DSTATCOM). In the proposed work, a detailed comparative study of four different effective control strategies for DSTATCOM to target reactive power compensation and Total Harmonic Distortion (THD). The results are demonstrated in detail using simulation performed in MATLAB-SIMULINK software which shows the good capability of four different control algorithms to provide good power quality for the electrical systems. The principal goal of any compensation process is to have a fast response, flexibility and should be easy to implement. The result’s approval is based on the Grid standards of Central Electricity Authority of India Regulations. The basic idea is to study the power quality issues and their best possible solutions. To achieve this goal four different control strategies for the comparative study viz.; Least Logarithmic Absolute Difference (LLAD), Synchronous Reference Frame Theory (SRF), Least Mean Logarithmic Square (LMLS), and ADALINE based LMS method to achieve power factor correction and THD reduction in the system according to the Indian Grid Standards. So that same DSTATCOM can be used to deal with the power quality issues in different situations with nonlinear loads in the fragile environments of electricity grids. All results have been interpreted through the simulations that have been performed in MATLABSIMULINK (SimPowerSystem) & a comparison is made to show the effectiveness of the different implemented control algorithms.
