Distance relays are prone to symmetrical power swing phenomenon.To mitigate this issue,a dynamic threshold-supported algorithm is proposed.A single logic is not supposed to be secure for all cases.Thus,a supervisory a...Distance relays are prone to symmetrical power swing phenomenon.To mitigate this issue,a dynamic threshold-supported algorithm is proposed.A single logic is not supposed to be secure for all cases.Thus,a supervisory algorithm,as proposed in this study,can aid in the improvement of the immunity of the relay during swing cases and be sensitive to symmetrical faults.In the developed stages,a three-phase power signal was used and processed in two different steps:(i)extraction of the effective intrinsic mode function(IMF)selected from the Kurtosis analysis using the wavelet synchro-squeezing transform,and(ii)estimation of the average Euclidean distance index using the absolute values of the decomposed IMF’s.The adaptive threshold facilitated resistance to swing situations.At the onset of a symmetrical fault,the proposed algorithm efficiently discriminated among events using a dynamic threshold.The IEEE 39-bus test system and Indian Eastern Power Grid networks were modelled using PSCAD software,and cases were generated to test the efficacy of the method.The impact of the proposed method on a large-scale wind farm was also evaluated.A comparative analysis with other existing methods revealed the security and dependability of the proposed method.展开更多
This paper involves a limit cycle oscillator-frequency lock loop(LCO-FLL)based control algorithm for unified power quality controllers-S type(UPQC-S)for compensation of reactive power,to maintain a unity power factor,...This paper involves a limit cycle oscillator-frequency lock loop(LCO-FLL)based control algorithm for unified power quality controllers-S type(UPQC-S)for compensation of reactive power,to maintain a unity power factor,regulate constant voltage at the PCC,mitigate sag,swell and to eliminate harmonics.In this approach,an extraction of fundamental in-phase and quadrature components for the estimation of reference signals are taken from the LCO-FLL circuit.The control LCO-FLL provides a high grade of protection against sag-swell voltages,unbalance loading and harmonics present in the utility grid.In addition to that,it has advantageous characteristics of synchronization with the grid frequency at any previously mentioned conditions without use of phase locked loops or trigonometric functions.Other advantages of the LCO-FLL are to give useful information to estimate fundamental components from a highly polluted grid scenario.The values obtained from the JAYA optimization algorithm are used to fine-tune the proportional integral(PI)controller gains,so that it maintains DC link voltage to the desired level.The mean square error(MSE)is employed as an objective function for optimizing the error between actual and reference values.The control algorithm based on LCO-FLL is developed in MATLAB/Simulink software and it is tested for power conditioning features.展开更多
文摘Distance relays are prone to symmetrical power swing phenomenon.To mitigate this issue,a dynamic threshold-supported algorithm is proposed.A single logic is not supposed to be secure for all cases.Thus,a supervisory algorithm,as proposed in this study,can aid in the improvement of the immunity of the relay during swing cases and be sensitive to symmetrical faults.In the developed stages,a three-phase power signal was used and processed in two different steps:(i)extraction of the effective intrinsic mode function(IMF)selected from the Kurtosis analysis using the wavelet synchro-squeezing transform,and(ii)estimation of the average Euclidean distance index using the absolute values of the decomposed IMF’s.The adaptive threshold facilitated resistance to swing situations.At the onset of a symmetrical fault,the proposed algorithm efficiently discriminated among events using a dynamic threshold.The IEEE 39-bus test system and Indian Eastern Power Grid networks were modelled using PSCAD software,and cases were generated to test the efficacy of the method.The impact of the proposed method on a large-scale wind farm was also evaluated.A comparative analysis with other existing methods revealed the security and dependability of the proposed method.
文摘This paper involves a limit cycle oscillator-frequency lock loop(LCO-FLL)based control algorithm for unified power quality controllers-S type(UPQC-S)for compensation of reactive power,to maintain a unity power factor,regulate constant voltage at the PCC,mitigate sag,swell and to eliminate harmonics.In this approach,an extraction of fundamental in-phase and quadrature components for the estimation of reference signals are taken from the LCO-FLL circuit.The control LCO-FLL provides a high grade of protection against sag-swell voltages,unbalance loading and harmonics present in the utility grid.In addition to that,it has advantageous characteristics of synchronization with the grid frequency at any previously mentioned conditions without use of phase locked loops or trigonometric functions.Other advantages of the LCO-FLL are to give useful information to estimate fundamental components from a highly polluted grid scenario.The values obtained from the JAYA optimization algorithm are used to fine-tune the proportional integral(PI)controller gains,so that it maintains DC link voltage to the desired level.The mean square error(MSE)is employed as an objective function for optimizing the error between actual and reference values.The control algorithm based on LCO-FLL is developed in MATLAB/Simulink software and it is tested for power conditioning features.
