Optimum Power Control Schemes For Energy Management In Renewable Energy Based Micro Grids

This thesis develop optimum power control novel schemes for the achievement of efficient power in renewable energy based micro grids and addresses the challenges associated with the optimum power,power losses,and power quality and energy management.Photovoltaic(PV)systems are gradually becoming the key renewable source of electrical energy.The great penetration of renewable energy sources(RES),solar and wind in micro grid have multiple tasks in modern power system as compared to conventional.Micro grids(MG)are a pioneering idea in power systems that can be described as independent power distribution systems of small and medium size that can be extracted smart and autonomous.It contains balancing power to avoid blackouts using energy storages against system loads,managing power flow,regulating voltage,and minimizing power quality issues by mitigating harmonics which caused for power losses.The major contributions and novelties of this thesis are summarized as follows:1)PV module require special techniques used to harvest maximum power and track Maximum Power Point(MPP)from the nonlinear I-V characteristics through power electronic circuits are known as Maximum Power Point Tracking(MPPT)techniques.A hybrid combination of variable-step sized Incremental Conductance(InC)with Fractional Short Circuit Current(FSCC)technique is proposed in this research work.Initially,the FSCC forces the PV system to work near MPP and then InC technique track the exact peak.Matlab/Simulink software is used to implement the proposed hybrid technique.Finally,the results verify its superior performance under rapidly changing environmental conditions.2)A novel soft computing technique is proposed using Water Cycle Algorithm(WCA)under partial shading conditions to attain maximum power point tracking(MPPT)of a photovoltaic(PV)power system.Among many renewable sources,solar energy has a substantial part to meet the increased energy demand with reduced environmental effect.Solar irradiance and temperature are key factors on which PV power generation depends.Finding the optimum operating point is a challenge due to nonlinear solar behaviour and varying nature of environmental conditions.To overcome these challenges MPPT techniques are used to get maximum power from the PV/solar system.MPPT behaviour is different under different environmental conditions such as partial shading,uniform conditions,and fast-changing environment.This work deals with the development of a novel technique for maximum power point tracking of a photovoltaic(PV)system based on Water Cycle Algorithm(WCA)under partial shading conditions.It is good in terms of exploration and exploitation.Thus,it has an excellent ability to avoid getting stuck in local optima and to find the global optimum point.The performance of the proposed technique is evaluated on five different types of P-V patterns on PV arrays under uniform and partially shading conditions.Results are compared with the other well-known AI soft computing method PSO and conventional method P&O in order to evaluate performance.The performance evaluation shows the superiority of the proposed WCA algorithm in terms of robustness,accuracy,efficiency,and reliability over P&O and in terms of convergence speed and efficiency over PSO.3)Solar/PV systems in micro grids are great examples for increasingly becoming popular solutions in renewable energy.As is known,maximizing power output from a solar/PV system is desirable to increase efficiency.In order to maximize heat output from the solar/PV systems,one needs to keep the system aligned with the sun.Intrinsically,the sun is required for tracking;it's a far more costing effectively solution,than purchasing additional solar/PV system placed in different angles.This research develops a hybrid tracking system which will keep the solar/PV system aligned with the sun in order to maximize heat efficiency.Solar energy is in form of dc and converted to ac with the help of inverter,which introduces distortion in sinusoidal wave and causes harmonics.Harmonics increase losses in power system.In addition,with harmonics due to fluctuating nature of energy from renewable sources and variation in load,to reduce the power factor and consequences are increasing in losses;it affects the transmission system and reduces the receiving power.Therefore,this project compacts with the analysis of the problems mentioned above and propose the feasible solutions to make the solar/PV system more reliable and efficient.4)The current drawn by compact fluorescent lamps(CFLs)is non-sinusoidal and rich in harmonics.Active power filters(APFs)are a popular method of reducing harmonic distortion.APFs are much used in industry for extenuation of harmonics created by six pulse rectifiers and AC drives.Estimating the harmonic component of load current is essential to the performance of active power filters.While harmonic current estimation methods are developed for larger industrial harmonic loads,their performance with smaller loads as CFLs varies.This work explores the effectiveness of the instantaneous reactive power theory(IRPT)and stationary frame method in estimating harmonic component current drawn by CFLs.An active power filter is modelled in using stationary frame method and its performance evaluated with six pulse rectifier load as well as three phase unbalanced CFLs load.5)Virtual Power Plant consists of a solar photovoltaic system,a wind turbine(WT)power generation system and an energy storage system(ESS)that is due to global warming,the virtual power plants are being explored,to reduce dependency on fossil fuels to meet the increased demand of electricity and achieve more efficient energy management.Multi-operating modes are generated by an Energy Management Strategy(EMS)that contingent on solar,wind and load power to control the planning operation of loads during dynamic weather and load conditions in order to avoid from blackout which is a key focus in this research.The PV and WT power generation systems are anticipated as the main sources of energy that fulfil the load demand in a steady way whereas the battery is used only as a backup for the exigency.Comprehensive models and design for entire research work mentioned above have been presented in this work for each system and its components under different situations also presented simulations and adequate comparisons under MATLAB/SIMULINK,software with previous strategies for verification of the efficiency of the proposed schemes.