Power System Frequency Control By Battery Energy Storage System

Micro grids are being another creating innovation operation in two particular methods of activity,in particular,the grid-connected mode and the self-governing(or islanded)mode.On the move from the utility-grid associated mode to the independent mode,the frequency of a micro-grid can be truly influenced because of unbalance between power generated and power request and right then and there,micro-sources may react gradually to dispose of this unbalancing circumstance.To fathom this interference and to work the micro grid relentlessly,some quick reaction storage system frameworks,in particular Battery Energy Storage Systems(BESSs)are required.Integration of Renewable Energy Sources into the Conventional Power plants have been a necessity of today’s World to satisfy the heavy demand and to promote the pollution-free environment.Converters play a vital role in controlling the output of these RES’s and convert the D.C output power of RES’s into A.C usable power.While these converters had gained a huge popularity due to its fast and controllable output power,at the same time it has disconnected the grid frequency from the generator’s rotor.This means no control over the grid frequency changes as the generator is unable to provide inertial response,Primary frequency response,and Damping response to the system.All large generating plant,and groups of smaller generators(such as wind farms),are normally required to have capability to participate in frequency control by supplying an increase in power if frequency drops below,and a decrease in power if frequency increases above a nominal frequency.This is achieved by operation at less than maximum available output in order to provide ability to regulate power production upwards.Generators which do not operate to provide this governor type response will normally still need to provide a high frequency response where active power is gradually reduced above a certain frequency.During low frequency no increase in active power is required,in fact an allowed reduction in power is specified to account for technology dependent characteristics of output power verses frequency for certain types of plant.Rise in Wind power plants have seen a large growth in recent years.High integration of these Renewable energy sources has greatly influenced today’s power system stability.When concerned about the stability,two variables carry a great importance,one is the frequency and the other is the voltage.This thesis will focus on frequency stability.With rise in the Renewable energy sources like Wind farms,and Photovoltaics,there is as equal decrement in the system inertia,and the primary frequency response.These two responses are the most reliable controls in any power system.With no interlink of grid frequency with the generator’s rotor,Renewables have failed to cope with the frequency disturbances.In these circumstances,Battery energy storage system came in front to minimize the differences between modern and conventional power plants(CPP),where modern power plants can be made to depict the characteristics same as with the CPP.The significant role of Battery Energy Storage System(BESS),in the standalone modern power systems,to improve the grid frequency response will be the primary focus of this study.Battery storage might be the realistic solution for providing the inertia and primary frequency regulation.This paper also presents the new approach to directly predict the size of BESS for the power systems using the Levenberg-Marquardt based optimized Artificial Neural Network(ANN)architecture.The technique is applied to the Average system frequency(ASF)model,with a large integration of wind power.The predicted size of BESS is compared with the formulated studies and demonstrates that ANN might be the efficient method in predicting the size of BESS for modern standalone power systems.This thesis has investigated how the Battery Energy storage system can be a feasible option to the frequency disturbances in a weak distribution grid.Also,ANN proved to be the effective solution to the problem of sizing of BESS for the modern standalone power systems.The investigation was carried on MATLAB by creating a weak distribution grid with a high penetration of Wind power plant.The active output power of BESS was controlled to mimic the IR,PFR,and Damping response as with the CPP.Frequency responses were compared with and without the BESS,which demonstrated the significance of initial responses to the frequency disturbances in a power system.Furthermore,ANN architecture used to determine the size of BESS for standalone grid is compared with the analytical calculations presented in literature,and the results shows that the size of BESS predicted by our trained neural network can effectively change the frequency to its allowable limits.