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The heat dissipation factor of conventional epoxy impregnated paper bushings is a subject of concern due to the large quantities of power in a High Voltage Direct Current (HVDC) system. The present work deals with the selection of better insulation as a replacement to the conventional resin impregnated material employing nano-hexagonal-Boron Nitride and nano-hexagonal-Boron Nitride added with nano-cellulose-fiber. The bushing of the converter transformer is designed using the Finite Element Method (FEM), and the electrothermal analysis is performed at the loaded working condition. Besides, numerous optimization schemes are also presented for adapting the structure of the thermal conductor enclosed in the inner conductor. The electrothermal performances of the above materials with the optimized structure are compared and an advanced scheme is proposed. Further, the results obtained from the designed system are employed in the form of an Artificial Neural Network to simplify the process of thermal computation characterized by the selected scheme. The internal parameters of the neural network are tuned implementing a hybrid amalgamation of Particle Swarm optimization - Grey Wolf Optimiser and the performance is compared against the actual values. The supremacy of the implemented algorithm is justified by a comparative analysis with other well-established algorithms using various statistical parameters.

In this work, the stability of a single area power system AVR loop is analysed in terms of specified gain and phase margin standpoint, by utilising an extended reduced-order observer (EROO). The de...

This paper illustrates various techniques to achieve the best optimization method under the Linear quadratic control strategy that is used for a multiple input multiple output system. The objective of the paper is to find the control criteria using the principle of extended state observer. An advanced optimized iteration method was introduced to select the weighted matrix Q from the control parameters. Another method is simulink response optimization method which also can fulfil the desired output result shown in the paper. Both the variables, the weighted matrix Q and the observer gain La, was modified after applying these optimization methods. The method responses were as per the minimal damping ratio of control logic. Among all these algorithms, the best iterative result was initiated.

The forces exerted due to the transient currents in a power transformer can result in deformity of core and winding. These transient currents are the excessive current arising in the transformer at the time of short-circuit fault. This study aims in examining the axial and radial force generated in the transformer's high voltage winding and the deformations associated with it when a double line short-circuit fault occurs. The analysis has been done for a three phase 11/66 kV power transformer of 40 MVA. Finite element method is employed using COMSOL Multiphysics. The electromagnetic force study is significant in determining various design parameters of the power transformer so as to protect it from the harmful effects taking place due to the transience in currents.

The work emphasises on the thermal behaviour of a High Voltage DC transformer on the occurrence of DC bias in the system. The DC bias can lead to temperature rise in the transformer and can form hotspot in the windings which may result in various issues including thermal breakdown among others. A two-dimensional design of the core and windings of the converter transformer is modelled using Finite Element Method and is considered for studying the thermal behaviour due to the presence of DC bias. The results are curve fitted to obtain a sigmoidal function describing the variation of hotspot temperature with respect to applied DC bias. The developed function is validated by choosing different values of DC biases. Besides, the statistical significance of the function has also been evaluated. The obtained results are encouraging in the prediction of the hottest spot temperature.

Renewable source of energy plays an important role in meeting the world’s power demands. The major factor that makes this source of energy to be important is due to its clean energy generation methodology. Hydro, wind and solar are effectively harnessed in almost every part of the world. However, solar energy, although has less environmental impacts, remains behind when compared to hydro and wind. For effective solar energy generation, it is necessary to know the amount of solar radiation that it receives in a month or a year at that location to harness and install photovoltaic (PV) system in that particular location. Solar radiation at any place can either be measured directly using instruments or empirically determined from global solar radiation. However, these methods are either expensive or not accurate. Artificial neural network (ANN) method provides a convenient approach to overcome the drawbacks of conventional instrumental or other empirical methods. ANN is analogous to human nervous system and are widely used for solving linear and nonlinear problems. This paper has developed neural network model for prediction of monthly solar radiation considering two places in Arunachal Pradesh, i.e., Itanagar and Pasighat. Multilayer feed forward network with back propagation has been proposed for the ANN model. Five-year meteorological data was collected and used for training the proposed network model. The network performance was checked by considering mean square error (MSE) and R (coefficient of correlation) which gave the value very close to zero above 92% for the considered location, respectively. Thus, the predicted output is almost in agreement with the actual output making this model applicable for prediction of monthly solar radiation for considered places. Apart for this prediction, performance of different combination of meteorological parameter were also evaluated and found that parameters such as temperature, humidity, sunshine hour and wind speed are found to be more influencing parameter for solar radiation estimation. This paper demonstrates that ANN has the potential to overcome many of the drawbacks and challenges in estimating the solar radiation, which is essential for designing solar energy generation panels. The findings are particularly useful in data sparse regions and highly applicable in regions where adequate energy supply is still a herculean task.

This study illustrates a review on various design method for disturbance rejection in control applications, in presence of external disturbances a state observer of optimal control is used. ESO (Extended State Observer) approximates the unknown states and with the help of it decreases the disturbance from the system to converge the system to be stable. The observer introduces reliability in the controller gain and dismisses the effect of external disturbance. The performance analysis was done here for industrial control system as well as laboratory systems too. One controller is proposed here to absorb the active disturbance for a higher order nonlinear system. From the nonlinear systems absorbing disturbance is very complex. If proper modeling of controller is not done then the system model may be not stable. The unknown states of the systems were identified and the disturbance was rejected. The stability of a high nonlinear system may be very difficult task, but this ESO has a higher impact on the stability of the system.

Extension of grid for remote rural electrification has been a challenge due to multiple factors including scattered population, poor road and communication connectivity and difficult terrain. Moreover, since their livelihoods are generally dependent upon small-scale farming, extension of grid for house lighting, basic necessity is uneconomical for the power supply agencies. To meet the need of such remote areas generating power locally through the available natural resources is considered more feasible. Hence, focus on Photovoltaic (PV) system, small hydropower system and other renewable resources are emerging to bridge the gap. In order to improve the efficiency and reliability of the power generation, protection of the system from different fault is of critical importance. PV systems consist of power generation in DC and AC stage and both suffer from different kinds of faults that is not easily detected since it is exposed to many kinds of fault that could be environmental or electrical. A conventional fault protection method uses fuses or circuit breakers in series with PV components. Some faults in PV arrays remain undetected due to its current-limiting property of the fuses and non-linear output characteristics of PV arrays. Therefore, this paper aims to develop a fault analysis in solar photovoltaic (SPV) arrays. In this paper literature on various fault detection algorithm and techniques have been discuss, PV array has been modelled and simulated for fault detection such as line to line (L-L), line to ground (L-G), open circuit and partial shading and their output characteristic has been compare.

The study illustrates a study of fractional order proportional-integral-derivative (FOPID) controller using active disturbance rejection controller. The strategy is applied to a helicopter model of multiple input multiple output system after designing with tuned controller parameters. The motive of the system is to accomplish the control criteria and to investigate the stability of the structure using the principle of non-integer PID controller with a nonlinear feedback and active disturbance rejection. The immense criteria for stability analysis of the coupled system along with the disturbance rejection characteristics are given here in this study. Two new fractional variables as λ and μ are introduced to get better performance. In addition, disturbance control is also implemented from the designed controller.

This study explains about the MIMO plant statistics of fuzzy logic based control of a electro-mechanical system. An intelligent control system is proposed here in this paper to observe all the response of both the planes horizontal and vertical. The controller was established for pitch and yaw planes separately which determines the desired output responses. A triangular response was selected in fuzzy logic controller to mitigate complexity of calculation and produce faster and smoother output stabilization which leads to better robustness. The model is highly nonlinear and model controller design is done by MATLAB simulation functions.

This study explains about the SIMO plant statistics of observer-based control to a rotational electro-mechanical system. A robust linear quadratic regulator controller is proposed here, in this study, to observe all the states after recognizing the linear model. The unknown states were determined by the method and for the tuning of the weighted matrices various methods were applied. This full state feedback controller was able to produce faster and smoother output stabilization, which leads to better robustness. The model is highly nonlinear, and model identification is done by MATLAB simulation procedure.

This paper presents a robust controller known as Extended State Observer (ESO) in order to improve the stability and voltage regulation of a synchronous machine connected to an infinite bus power system through a transmission line. The ESO-based control scheme is implemented with an automatic voltage regulator in conjunction with an excitation system to enhance the damping of low frequency power system oscillations, as the Power System Stabilizer (PSS) does. The implementation of PSS excitation control techniques however requires reliable information about the entire states, though they are not always directly measureable. To address this issue, the proposed ESO provides the estimate of system states as well as disturbance state together in order to improve not only the damping but also compensates system efficiently in presence of parameter uncertainties and external disturbances. The Closed-Loop Poles (CLPs) of the system have been assigned by the symmetric root locus technique, with the desired level of system damping provided by the dominant CLPs. The performance of the system is analyzed through simulating at different operating conditions. The control method is not only capable of providing zero estimation error in steady-state, but also shows robustness in tracking the reference command under parametric variations and external disturbances. Illustrative examples have been provided to demonstrate the effectiveness of the developed methodology.

This paper presents an extended reduced-order observer (EROO) in order to improve the stability and voltage regulation of a synchronous machine connected to an infinite bus power system through a transmission line. The EROO-based control scheme is implemented with an automatic voltage regulator to enhance the damping of low frequency power system oscillations, so that the deviations in terminal voltage are reduced. The proposed observer reconstructs the unmeasurable states of the system and state of the disturbance model simultaneous to implement full state feedback and using the estimated disturbance state to compensate the system efficiently in presence of external and parameter uncertainties. The closed-loop poles (CLPs) of the system have been assigned by the symmetric root locus technique, with the desired level of system damping provided by the dominant CLPs. The performance of the system is analyzed through simulating at different operating conditions. The control method is not only capable of providing zero estimation error in steady-state, but also shows robustness in tracking the reference command under parametric variations and external disturbances. Illustrative examples have been provided to demonstrate the effectiveness of the developed methodology.

The transient current in the transformer winding leads to deformation of core and winding. This paper examines the electromagnetic force and winding deformation occurring in the transformer due to short-circuit current. Axial and radial forces are generated in the transformer winding which leads to its distortion. This work aims to study about these mechanical forces and analyse its effect on a 3-phase, 3 leg, 66/11 KV transformer. Finite element analysis is done on a 40 MVA power transformer with the help of COMSOL Multiphysics. The study is important for designing the transformer in such a way to keep the damages originated due to abnormal conditions like faults and other transients at the bay. The electromagnetic force study is important for manufacturing and operational consideration.

The design problem of an interconnected power system implemented with a power system stabilizer (PSS) can be formulated as a simple optimization problem. This paper describes two systematic approaches to optimization issues by tuning the controller parameters utilizing hybrid HPSS, obtained by combining phase compensation technique with integral of squared error (ISE) criterion and genetic algorithm GPSS with integral of time multiply absolute error (ITAE) technique as objective functions. The two control methodologies have been developed for synchronous machine infinite bus (SMIB) power system. The HPSS and GPSS computes and searches for the optimal parameter settings and simultaneously, enhance the damping of low frequency oscillations and stabilize the system. The transfer functions of the dynamic model, inclusive of excitation system and PSS have been deduced using Mason’s graph to evaluate the performance indices and carry out the search processes. Simulations were carried out under different plant conditions employing MATLAB and GEATbx for use with MATLAB. Simulation result shows the viability and effectiveness of the designed methodologies under perturbed and parametric conditions.

Using an anti-windup property an illustrative example of multivariable system is provided here in this study. An estimator has been designed using the logic anti-windup, where proportional integral control law is applied to perform the analysis. Controlling a single input single output system is very simple but for a multivariable system controlling becomes complex. The estimator is activating the observer and using parameters unknown states of the plant estimated. Now using this control logic unwanted external disturbances also was mitigated using the anti-windup state observer based controller (AWC).

This study illustrates the applications of the recently developed modern optimization techniques. Designing a controller for multiple input multiple output is a big challenge in control system application. To overcome the difficulties of analysing MIMO system a comparative statement of various solutions are prepared in this paper. The study is being done on manual tuning of linear quadratic regulator (LQR) parameters over genetic algorithm (GA) and particle swarm optimization (PSO) algorithm based parameters. The best optimized result is shown and discussed in this study. The comparison is being done the basis of standard deviations in the values of parameters and objective functions.

This study demonstrates a non integer order proportional integral derivative controller based on parameter design tuning method to achieve the best optimized response. The methodology was to decouple a multiple input multiple output twin rotor system into single input single output and apply fractional order PID (FOPID) to the bifurcated models. The objective of the system was to fulfill the response characteristics based on classical PID controller. A method named as Simulink Response optimization (SRO) is introduced for tuning the desired output result which is shown in this paper. λ and μ are the two new fractional operators added to the PID controller to get a better performance.

As an alternative to power system stabilizer, this paper presents a robust controller known as extended state observer (ESO) for synchronous machine connected to an infinite bus (SMIB) power system. The ESO-based control scheme is implemented with an automatic voltage regulator in order to enhance the damping of low frequency power system oscillations so that the deviations in terminal voltage are compensated. The proposed ESO provides the estimates of system state as well as disturbance state together in order to improve the damping as well as compensate system efficiently in presence of parameter uncertainties and external disturbances. The closed-loop poles (CLPs) of the system have been assigned by the symmetrical root locus technique, with the desired level of system damping provided by the dominant CLPs. The performance of the system is analysed through simulating at different operating conditions. The control method is not only capable of providing zero estimation error in steady-state, but also shows robustness in tracking the reference command under parametric variations and external disturbances. Illustrative examples have been provided to demonstrate the effectiveness of the developed methodology.

Low frequency oscillations (LFO) are a frequent harmful phenomenon which increases the risk of instability for the power system. They limit the steady-state power transfer and change the operational system economics and security. The identification of LFO and solution to LFO problems with reference to power system stabilizer is carried out in this literature survey.

In a power system, as a power load demand varies randomly, both area frequency and line power also vary. The objectives of load frequency control (LFC) are to minimize the transient deviations in these variables (area frequency and line power) and to ensure their steady state errors to be zeros. When dealing with the LFC problem of power systems, unexpected external disturbances, parameter uncertainties and the model uncertainties of the power system pose big challenges for controller design. In this project, a reduced-order state observer with a practical point of view for LFC problem in a power system is proposed based on the pole-placement method. A proper choice of closed-loop pole location has been proposed using symmetrical root locus (SRL) method. In the practical environment, there is limited access to all state variables of system and measuring all of them is usually impossible. So when the available sensors are less than the number of states or when it may be undesirable, expensive or impossible to measure directly all of the states, a reduced-order state observer can be applied as proposed in this project. The proposed strategy is tested on a single area power system. The dynamic model of the power system and the controller design based on the model are elaborated. The robustness and stability of the control schemes is examined through simulations.

A full-order observer-based state feedback linear controller design approach for a single area load frequency problem is presented. The load frequency control model incorporates integral control for improved command tracking response and disturbance rejection. A full state feedback is implemented through full-order state observer design. State feedback with integral controllers design is carried out through a pole-placement technique using symmetrical root locus method. Parametric model uncertainty has been considered and stability robustness study has been carried out assigning a bound on the deviations in parameters of single area load frequency model. The proposed design methodology achieves performance satisfying the specified stability margins. The methodology provides a control over peak values of the frequency and control signal deviations which may be utilized to meet hardware constraints. A numerical example illustrates the effectiveness of the developed methodology.

An automatic voltage regulator (AVR) design based on symmetric root locus (SRL) technique for a synchronous machine infinite bus (SMIB) power system is presented. The SRL technique is used to minimise the amplifier saturation by placing the closed-loop poles (CLPs) of the system at desired locations. The desired CLPs are decided by considering the dominant pole locations that provide maximum damping on the SRL plot. The design incorporates an extended estimator to deal with uncertainties introduced due to variations of parameters or operating conditions. They reconstruct the state information including the state of disturbance dynamics simultaneous to implement full state feedback and using the reconstructed disturbance estimate to compensate the effect of external disturbance or parameter uncertainties. The performance of the system is analysed through simulating at different operating conditions. The control method improves the tracking response and provides zero estimation error in the steady-state. Illustrative examples have been provided to demonstrate the effectiveness of the developed methodology.

Decentralized load frequency control is more suitable for a large scale power system. Extended State Observer (ESO) based Decentralized load frequency control is implemented in this paper. Here an interconnected system consisting of combinations of three areas Thermal non-reheat, thermal Reheat and Hydro are considered. The state space model of individual system is designed for Extended State Observer (ESO). The controller poles for individual systems have been obtained by using the symmetrical root locus (SRL) technique. Observer poles for the extended system are kept in such a way that they satisfy required Gain margin and Phase margin criteria for individual power system. The designed system provides zero steady state error for frequency deviation and shows robustness in the face of parameter uncertainty. A numerical example illustrates the ability of the designed system to provide zero frequency deviation in its output and robustness against changing demands and parameter uncertainties.

In this paper different electrostatic interdigitated comb designs for the new concept of MEMS based DC–AC capacitive power inverter for the solar photovoltaic applications has been compared and tested on the basis of different structures and materials used as a frame for the proposed model. To obtain better the performance and power conversion efficiency of the interdigitated comb drive capacitive DC/AC inverter at very low input voltage some structural parameters of the proposed model has been varied such as increase the number of comb fingers; reduced the gap between the fingers of the interdigitated comb with increase in thickness of the fingers and made uniformly tapered at its edges. As a structural material for the proposed model the polysilicon and indium antimonite has been employed, simulated, compared and tested and in COMSOL Metaphysics 5.0 environment with different comb structure to get better performances for solar photo voltaic application. The proposed MEMS DC/AC power inverter model can easily compete with the commercially available semiconductor inverters once it is implemented with efficient fabrication technology due to its certain merits over semiconductor power inverter in terms of miniaturized size, pure sinusoidal output voltage and current, regulated output frequency, ultra low power consumption, very low cost and off course very small or minimal power loss.

This paper presents an Extended State Estimator based controller for two area system. Using a state space Disturbance Observer has been proposed without using any integral control directly, to achieve constant rated frequency in the face of parameter uncertainties and system disturbances. The controller is constructed for a two-area power system which is identical in nature. The dynamic model of the power system and the controller design based on the model are elaborated in the report and the effectiveness of the proposed method is illustrated using numerical analysis.

The modern electric power distribution system faces lots of power quality (PQ) problems such as short and long duration voltage variations, voltage imbalance, waveform distortions, impulsive and oscillatory transients and voltage flicker etc. The custom power devices (CPD) have been designed and developed with the aim of mitigating these problems. The major CPDs introduced so far include distribution-static synchronous compensator (D-STATCOM), dynamic voltage restorer (DVR), unified power quality conditioners (UPQC), active power filters (APF) etc. However, most of these CPDs are designed and implemented using voltage source converter (VSC) topology. Although lots of research works have been carried out for realizing DVR system based on VSC topology, not much research work has been reported on the application of CSC topology in DVR system over the last one decade. Through this paper, it has been attempted to develop a model of DVR system based on CSC topology capable of performing dual power quality enhancement tasks viz. voltage regulation and harmonics mitigation at a power distribution system catering power to a variety of loads. The DVR system has been modeled and simulated in the MATLAB / Simulink platform and the simulation results reveal the effectiveness and validity of the proposed model for use in power distribution system.

State estimation of power system is an important tool for operation, analysis and forecasting of electric power system. In this paper, a Kalman filter algorithm is presented for static estimation of power system state variables. IEEE 14 bus system is employed to check the accuracy of this method. Newton Raphson load flow study is first carried out on our test system and a set of data from the output of load flow program is taken as measurement input. Measurement inputs are simulated by adding Gaussian noise of zero mean. The results of Kalman estimation are compared with traditional Weight Least Square (WLS) method and it is observed that Kalman filter algorithm is numerically more efficient than traditional WLS method. Estimation accuracy is also tested for presence of parametric error in the system. In addition, numerical stability of Kalman filter algorithm is tested by considering inclusion of zero mean errors in the initial estimates.

This paper presents a novel method of realizing one of the custom power controllers, the distribution static synchronous compensator (D-STATCOM) using current source converter (CSC) topology. Almost all the custom power controllers such as dynamic voltage restorer (DVR), unified power quality conditioner (UPQC) including D-STATCOM are generally designed and implemented by using voltage source converters (VSC) and not much research publications with CSC based approach has been reported over the last one decade. Since the D-STATCOM is a current injection device, its performance can be improved when realized by a current-source converter which can generate a controllable current directly at its output terminals and offers many advantageous features. In this paper, an attempt has been made to study the performance of a CSC based D-STATCOM suitable for use in the power distribution system in order to mitigate voltage sag and improve power quality. The proposed model uses a three leg CSC whose switching strategy is based on sinusoidal pulse width modulation (SPWM). The model has been simulated in the Matlab/Simulink environment. The results of the simulation runs under steady state and dynamic load perturbation provide excellent voltage and current waveforms that support the justification of the proposed model.