ارزيابي و بهبود عملكرد ناحيه سوم رله ديستانس در شرايط كاهش حاشيه پايداري ولتاژ بلندمدت و گذرا

چكيده انگليسي :

Evaluation and Modification of Distance Relay Zone 3 Performance in the Conditions of Reducing the Long Term and Transient Voltage Stability Margin Jamal Dehghani Ashkezari j dehghani@ec iut ac ir March 10 2021 Doctor of Philosophy Dissertation Department of Electrical and Computer Engineering Isfahan University of Technology 84156 83111 Isfahan IranSupervisor Prof Mohamad Esmail Hamedani Golshan hgolshan@cc iut ac irAdvisor Dr Ahmad Mirzaei mirzaei@yazd ac irDepartment Graduate Program Coordinator Dr Behzad Nazari Department of Electrical and Computer Engineering Isfahan University of Technology 84156 83111 Isfahan Iran Department of Electrical Engineering Faculty of Engineering Yazd University 97514 Yazd IranAbstractUnwarranted operation of Zone 3 of the distance relays during voltage degraded conditions and prolonged voltagelevel reduction caused by the fault induced delayed voltage recovery FIDVR event may cause cascade outagesand voltage instability in the power system This dissertation first proposes a novel scheme to identify the criticaldistance relays considering voltage stability and online calculating of Zone 3 setting of the relays subjected tomal operation The proposed scheme is based on time based and line loading based indices defined by thecombination of a new concept of relay margin RM and the rate of change of the apparent impedance calculatedby local voltage and current measurements The indices appropriately indicate the power system situation takinginto account the voltage stability Therefore the scheme uses the mentioned indices in the online Zone 3 settingof the critical relays for keeping the maximum backup protection The proposed scheme is effective under long term voltage stability margin reduction with slow acting dynamics of power system but it must be improved fordynamic voltage transient conditions caused by FIDVR event Accordingly the new concept of RM along withthe rate of change of the apparent impedance and time variant NERC WECC severity indices are employed toinvestigate the possible operation of distance relay during the FIDVR event and proposing an auxiliary protectionalgorithm to effectively prevent its mal operation during short term dynamic voltage transient The proposedalgorithm estimates the critical time and voltage level at which the impedance trajectory arrives in Zone 3 of thecritical relays Then the critical voltage is compared with the expected voltage level at the estimated critical timecalculated by piecewise cubic spline interpolation PCSI method and three consecutive voltage phasors to decideabout the block of relays which entering the impedance trajectory to their Zone 3 is probable during the FIDVRevent Developing analytical formulation for indices using only local measurements simplicity and theapplicability for the modern numerical relays are the main advantages of the proposed schemes Concepts howto apply and the simulation results are demonstrated with the help of the New England 39 bus system Key Words Distance Relay Mal Operation Voltage Degraded Conditions Cascade Outages Zone3 FIDVR Dynamic Voltage Transient IntroductionThe rapid growth of electrical energy demand has led to operate modern power systems closeto their stability limits for more utilization of the existing asset and delaying the newinvestments The operation of power system under such conditions increases the risk of voltageinstability Besides as a short term depressed voltage condition in power systems faultinduced delayed voltage recovery FIDVR event has been an important challenge forresearchers and engineers over recent years A likely issue during such conditions is theunwarranted operation of Zone 3 of the distance relays that has been a participating factor in

دهقاني اشكذري، جمال

ارزيابي و بهبود عملكرد ناحيه سوم رله ديستانس در شرايط كاهش حاشيه پايداري ولتاژ بلندمدت و گذرا