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Fault Location In Distribution Feeders Containing Distributed Generation. Darla King Adly A. Girgis IEEE Student Member IEEE Fellow. Introduction of DG A Modified Fault Location Method? Overview of the Modified Zabc Method Analysis Future Research. Outline. Microturbine
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Fault Location In Distribution Feeders Containing Distributed Generation Darla King Adly A. Girgis IEEE Student Member IEEE Fellow
Introduction of DG A Modified Fault Location Method? Overview of the Modified Zabc Method Analysis Future Research Outline
Microturbine Small, high-speed generator power units Consists of a turbine, a compressor, and a two-pole permanent magnet generator Can produce from 25kW-100kW of power by conversion of fossil fuels. Fuel Cell Produces energy in the form of electricity and heat as long as fuel is supplied A fuel cell does not run down or require recharging Consists of two electrodes around an electrolyte Oxygen passes over one electrode and hydrogen over the other, generating electricity, water and heat Distributed Generation
Wind Energy Wind generators produce power depending on wind speed. The wind is an indirect form of solar energy, and is therefore “renewable” Wind passing over the blades is converted into mechanical power, which is fed through a transmission to an electrical generator Solar Energy(Photovoltaic) Electricity can be produced from sunlight through a photovoltaics (PV) process solid-state electronic cell produces direct current electrical energy from the radiant energy of the sun. Distributed Generation
Introduction of Distributed Generation in Distribution Systems Unidirectional to Multi-directional power flow Need modified method to eliminate errors inherent with using older fault location techniques that do not account for distributed generation Why Is There The Need For A Modified Fault Location Method?
What is Zabc Method? Uses Three-phase components Based on Steady-State Analysis During Fault Conditions Why Choose Zabc Method? Can be Applied to Balanced and Unbalanced Systems Does not assume ideally transposed lines Does not assume mutual coupling between phases are equal Zabc Method?
Solve for Initial Fault Distance: Do(Without any contributions from the DG’s) Example: Single Line-To-Ground Fault é ù é ù é ù é ù V Z Z Z I V sA aa ab ac sA FA ê ú ê ú ê ú ê ú = + V Z Z Z xD I V ê ú ê ú ê ú ê ú sB ba bb bc o sB FB ê ú ê ú ê ú ê ú V Z Z Z I V ë û ë û ë û ë û sC ca cb cc sC FC = + + + V Z I Z I Z I D I R sA aa sA ab sB ac sC o FA F Modified Zabc Method [ ] é ù é ù é ù - - - - D ( R I X I R I X I R I X I ) I V 1 + + = o aa sAr aa sAi ab sBr ab sBi ac sCr ac sCi FAr sAr ê ú ê ú ê ú R ( R I X I R I X I R I X I ) I V + + + + + ë û ë û ë û F aa sAi aa sAr ab sBi ab sBr ac sCi ac sCr FAi sAi ´ - ´ ( V I ) ( V I ) = sAr FAi sAi FAr D o ´ - ´ ( a I ) ( b I ) FAi FAr
Dj Calculate Fault Location Voltage : VFabc Update Fault Current : IF(j+1) = IFj + IDGj Calculate New Distance : D(j+1) Modified Zabc Method Calculate Currents Fed From the DG’s : IDGj Compare Dj and D(j+1) | D(j+1) – Dj | < 0.1% Distance to Fault = D(j+1)
System Is Source Idg1 Idg2 Idg3 DG1 DG2 DG3 L1 L2 – L1 L3 – L2 12.47KV System 100MVA Base L1 = 1.5 miles L2 – L1 = 0.75 miles L3 – L2 = 1.2 miles
Pick a Particular Fault Location along the Line Fault Analysis Find Source Voltages Find Source Currents Data Preparation
Zabc Method Solve for Initial Distance to Fault Continue Iterative Process until Final Distance to Fault is Found Compare Distance Found to Actual Distance Determine Accuracy of Zabc Method Analysis
Analysis • Single Line-To-Ground Fault • Zabc Method • Split System into 4 Sections • Do < L1 • L1 < Do < L2 • L2 < Do < L3 • Do > L3 • Solve For VFabc • Find All DG currents • Find new fault current : IF(j+1)=IFj+IDGj • Calculate new fault distance:D(j+1) • Repeat until D(j+1) – Dj < 0.1% F Is Is+Idg1 Is+Idg1+Idg2 Idg3 Source Idg1 Idg2 Idg3 DG1 DG2 DG3 L1 L2 – L1 L3 – L2
Iteration Process Yielded: Dfinal=3.0426 mi Compare Dfinal(3.0426 mi) to Dactual(3.05 mi) % Error = .243 % Dactual = 3.05 mi Dfinal = 3.0426 mi Results
Results Source & DG1 DG1 & DG2 DG2 & DG3 Past DG3
Reduce Errors in Fault Location Method Due to the Availability of Fault Data on Distribution Lines Method based on Voltage and Current Data at Beginning of Faulted Line Segment Consider Larger System and Account for Loads Test Zabc Method with new system Future Research
Construct Algorithm to convert the voltage and current waveforms into phasor quantities needed for fault location method Use an Electromagnetic Transients Program to simulate the voltage and current waveforms during fault conditions Obtain Actual Recorded Data from a Fault Recorder Test Zabc Method with Simulated Data and Actual Data Future Research