Shifting of research trends in islanding detection method-a comprehensive survey

The augmentation in electricity demand,power system privatization as well as efficacy of renewable resources has paved the way for power system companies and researchers to exploit the field of grid connected distributed generation(DG)and its issues,islanding being a dominant one.Several research works have been conducted to mitigate the issues of islanding detection(ID).In context of this,the paper gives a comprehensive review of islanding issues,standard test systems,criteria and shifting of research trends in islanding detection methods(IDMs).The significant contributions pertain to categorization of IDMs,evaluation of non-detection zone(NDZ)for each test system,disquisition on evolution and advancement of IDMs and its comparisons based on criteria such as NDZ,run on time,nuisance tripping percentage,applicability in multi DG system and implementation cost to draw out the strength and shortcomings of individual methods that will come to aid to the companies or researchers for establishing the applicability and appropriateness of such method for their concerned domain.

An adaptive supervised wide-area backup protection scheme for transmission lines protection

Maloperation of conventional relays is becoming prevalent due to ever increase in complexity of conventional power grids.They are dominant during power system contingencies like power swing,load encroachment,voltage instability,unbalanced loading,etc.In these situations,adaptive supervised wide-area backup protection(ASWABP)plays a major role in enhancing the power system reliability.A balance between security and dependability of protection is essential to maintain the reliability.This paper proposes multi-phasor measurement units(MPMU)based ASWABP scheme that can function effectively during faults besides power system contingencies.MPMU is an extended version of Phasor Measurement Unit(PMU).It is an intelligent electronic device which estimates the synchronized predominant harmonic phasors(100Hz and 150Hz)along with the fundamental phasors(50Hz)of three phase voltages and currents with high precision.The proposed ASWABP scheme can detect the fault,identify the parent bus,determine the faulty branch and classify the faults using MPMU measurements at System Protection Center(SPC).Based on these MPMU measurements(received at phasor data concentrator(PDC)at SPC)the appropriate relays will be supervised to enhance the overall reliability of the power grid.Numerous case studies are conducted on WSCC-9 bus and IEEE-14 bus systems to illustrate the security and dependability attributes of proposed ASWABP scheme in MATLAB/Simulink environment.Also,comparative studies are performed with the existing conventional distance protection(Mho relays)for corroborating the superiority of the proposed scheme regarding security and dependability.Comparative studies have shown that the proposed scheme can be used as adaptive supervised wide-area backup protection of conventional distance protection.