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WECC Composite Load Model WECC MVWG Meeting Bellevue, WA August 25, 2011 Slide 2 Motion Approve the implementation plant for replacing the interim load model with a Phase 1 composite load model Use default data sets Residential air-conditioner stalling disabled* * No revision of the WECC reliability criteria is needed Slide 3 Composite Load Model Development Slide 4 4 In the first 40 years of digital simulations, the focus was on modeling the supply side o We have reasonably good power plant models o Models data is to get more consistent as more plants have digital controls o We have tools for power plant model validation using disturbance data Now, the focus is shifting on modeling the supply side Load Modeling Slide 5 Loads will play much more influential role in power system stability Resistive-type loads are phasing out (incandescent lights and resistive heating) o Energy inefficient but exhibit grid-friendly behavior Power Electronic loads, VFDs, AC compressors, heat pumps, CFLs, LEDs are gaining their presence o Energy efficient but have undesirable characteristics from standpoint of dynamic stability Increasing penetration of residential air-conditioners Upcoming big changes on demand-side: Electric vehicl chargers Distributed generation Reasonable models are needed to understand the system impacts of these changes, to plan and operate the system and to develop appropriate standards Slide 6 6 We can now achieve the great accuracy with generator models: o We model physical equipment that is well defined and under our control We will never be able to achieve a comparable level of accuracy with load models o Load models will not be able to predict details o Load models should be capable of representing the load response in principle Load Modeling Setting Expectations Slide 7 7 WECC Load Modeling Philosophy WECC uses a physical-based modeling approach: Bottom-up model development Develop models that represent physics and characteristics of the actual end-use components Top-down model validation Validate and calibrate model data using disturbance recordings Slide 8 8 1980s Constant current real, constant impedance reactive models connected to a transmission bus o Reflected the limitation of computing technologies of that time 1990s EPRI Loadsyn effort o Several utilities use static polynomial characteristics for load representation 1990s IEEE Task Force recommends dynamic load modeling o The recommendation does not get much traction in the industry 1996 BPA model validation study for August 10 1996 outage: o Need for motor load modeling to represent oscillations and voltage instability History Of Load Modeling in WECC Slide 9 9 2000 2001 WECC Interim Load Model: o Presently used in planning and operational studies in WECC o 20% of load is represented with induction motors, the remaining load is static, mainly constant current active, constant impedance reactive components o Tuned to match inter-area oscillations for August 10 1996 and August 4, 2000 events o Interim load model was intended as a temporary solution to address oscillation issues observed at California Oregon Intertie o The model limitations and the need for a composite load model were recognized History Of Load Modeling in WECC Slide 10 10 Late 1980s Southern California Edison observed events of delayed voltage recovery attributed to stalling of residential air-conditioners o Tested residential air-conditioners, developed empirical AC models 1997 SCE model validation study of Lugo event: o Need to represent a distribution equivalent o Need to have special models for air-conditioning load History Of Load Modeling in WECC Slide 11 Southern California Edison Lugo Event Load Modeling Lessons: A. Need to represent a distribution equivalent B. Need to have special models for residential air-conditioners Slide 12 12 1994 Florida Power published an IEEE paper, used a similar load model 1998 Events of delayed voltage recovery were observed in Atlanta area by Southern Company, the events are analyzed and modeled Southern Company and Florida Power used in principle similar approaches to SCEs and eventually WECC model Load Modeling Efforts in the East Slide 13 13 2005 WECC developed explicit load model: o Adding distribution equivalent to powerflow case (PG&E) o Modeling load with induction motors and static loads o Numerically stable in WECC-wide studies ! 2007 PSLF has the first version of the composite load model (three-phase motor models only) 2006-2009 SCE-BPA-EPRI testing residential air- conditioners and developing models 2009 residential air-conditioner model is added to the composite load mode WECC Load Modeling Task Force Slide 14 14 1.Composite Load Model Structure 2.Default data sets a.Load composition b.Load component data c.Distribution equivalent 3.Tools for data management 4.Validation studies 5.System impact studies WECC Load Modeling Task Force Slide 15 WECC Composite Load Model (CMPLDW) Electronic M M M 69-kV 115-kV 138-kV Static AC 12.5-kV 13.8-kV UVLS UFLS Slide 16 Composite Load Model Structure Composite load model structure is implemented in General Electrics PSLF, Siemens PTI PSSE, Power World Simulator Similar model exists in PowerTechs TSAT TSS approved Composite Load Model Structure Slide 17 Load Model Data Slide 18 WECC Composite Load Model Electronic M Load Model Composition Data M M 115-kV 230-kV Static Load Component Model Data Distribution Equivalent Data UVLS and UFLS Data M Slide 19 Distribution Equivalent Data Electronic M M M 69-kV 115-kV 138-kV Static M X = 8% LF = 110% Tap = +/- 10% V = 4 to 6% V = 4 to 6% X/R = 1.5 PL < 7% B1:B2 = 3:1 V = 1.02 1.04 V > 0.95 B1 B2 R + j X Bss Slide 20 20 WECC Climate Areas IDClimate ZoneRepresentative City NWCNorthwest CoastSeattle, Vancouver BC NWVNorthwest ValleyPortland OR NWINorthwest InlandBoise, Tri-Cities, Spokane RMNRocky Mountain NorthCalgary, Montana, Wyoming NCCNorthern California CoastBay Area NCVNorthern California ValleySacramento NCINorthern California InlandFresno SCCSouthern California CoastLA, San Diego SCVSouthern California ValleyLA, San Diego SCISouthern California InlandLA, San Diego DSWDesert SouthwestPhoenix, Riverside, Las Vegas HIDHigh Desert Salt Lake City, Albuquerque, Denver, Reno Slide 21 21 California Energy Commission: 2006 California Commercial End-Use Survey (CEUS) LBNL Reports on Electricity Use in California PNNL DOE2 building simulations BPA-PNNL End-Use Load Characterization Assessment Program (ELCAP) BPA Building Data Load shapes provided by WECC members Load Composition Information Slide 22 California Commercial End-Use Survey 15 climate zones in California Four seasons Typical, Hot, Cold, Weekend 24-hour data Data is available on CEC web-site bottom top Slide 23 23 LBNL Electricity Use In California Study Residential AC Commercial AC Lighting Slide 24 24 CEC / BPA hired PNNL to develop load composition data Detailed models of various building types Residential loads are modeled using ELCAP data and DOE-2 models Commercial loads are taken from CEUS WECC developed mapping from end-uses to models PNNL Load Composition Model Slide 25 25 Slide 26 26 Slide 27 27 Load Class Model Components Slide 28 28 Portland Metro Area BPA SCADA Slide 29 29 Portland Metro Area BPA SCADA Slide 30 30 There is a balance between precision and the amount of effort required to maintain the data sets Based on the understanding developed using PNNL tool, WECC developed a simplified LCM version to create default data sets Produces load composition data for summer (normal, peak, cool), shoulder (normal) and winter (normal) days WECC Load Composition Model Slide 31 31 WECC Load Composition Model (Light) Slide 32 32 Better understanding of electrification by regions, and ultimately by substations Validation of building models Right now commercial data is extrapolated from California CEUS, and residential data is used from ELCAP Validation of load shapes at substation level: Use customer mix data and models to produce load shapes Validate the load shapes using SCADA data (5- min and 1hour are available from BPAT) Future work Slide 33 33 If you want detailed load composition information for your specific area, please contact David Chassin at PNNL David.Chassin@pnl.gov David.Chassin@pnl.gov Detailed analysis is currently done for substations in Seattle, Portland and Phoenix Expert Help is Available Slide 34 34 Motor Data Slide 35 35 Commercial Compressor Motor Slide 36 36 Commercial Fan and Pump Motors Slide 37 Slide 38 38 Industrial compressors: Trip and lock-out - half at 75%, half at 65%, 3 to 5 cycles Industrial fans and pumps Trip and lock-out - half at 75%, half at 65%, 3 to 5 cycles Commercial compressors o Trip and lock-out: 20% of motors, trip < 60% 2 cycles o Trip and reclose: remaining, trip 60% for 0.2 sec Fans and pumps o Trip and lock-out: 20% of motors, trip < 60% 2 cycles o Trip and reclose: remaining, trip 60% for 0.2 sec Protection Slide 39 Tools for Load Model Data Management Slide 40 WECC Composite Load Model cmpldw 43085 "CANYON " 115.00 "1 " : #1 mva=63.18 "Bss" 0 "Rfdr" 0.032 "Xfdr" 0.04 "Fb" 0.749/ "Xxf" 0.08 "TfixHS" 1 "TfixLS" 1 "LTC" 1 "Tmin" 0.9 "Tmax" 1.1 "step" 0.00625 / "Vmin" 1.025 "Vmax" 1.04 "Tdel" 30 "Ttap" 5 "Rcomp" 0 "Xcomp" 0 / "Fma" 0.234 "Fmb" 0.157 "Fmc" 0.032 "Fmd" 0.103 "Fel" 0.136 / "PFel" 1 "Vd1" 0.75 "Vd2" 0.65 "Frcel" 0.35 / "Pfs" -0.99274 "P1e" 2 "P1c" 0.307692 "P2e" 1 "P2c" 0.692308 "Pfreq" 0 / "Q1e" 2 "Q1c" -0.5 "Q2e" 1 "Q2c" 1.5 "Qfreq" -1 / "MtpA" 3 "MtpB" 3 "MtpC" 3 "MtpD" 1 / "LfmA" 0.75 "RsA" 0.04 "LsA" 1.8 "LpA" 0.12 "LppA" 0.104 / "TpoA" 0.095 "TppoA" 0.0021 "HA" 0.05 "etrqA" 0 / "Vtr1A" 0.7 "Ttr1A" 0.05 "Ftr1A" 0.2 "Vrc1A" 1 "Trc1A" 9999 / "Vtr2A" 0.55 "Ttr2A" 0.03 "Ftr2A" 0.75 "Vrc2A" 0.65 "Trc2A" 0.1 / "LfmB" 0.75 "RsB" 0.03 "LsB" 1.8 "LpB" 0.19 "LppB" 0.14 / "TpoB" 0.2 "TppoB" 0.0026 "HB" 0.5 "etrqB" 2 / "Vtr1B" 0.65 "Ttr1B" 0.05 "Ftr1B" 0.1 "Vrc1B" 1 "Trc1B" 9999 / "Vtr2B" 0.6 "Ttr2B" 0.03 "Ftr2B" 0.1 "Vrc2B" 1 "Trc2B" 99999 / "LfmC" 0.75 "RsC" 0.03 "LsC" 1.8 "LpC" 0.19 "LppC" 0.14 / "TpoC" 0.2 "TppoC" 0.0026 "HC" 0.15 "etrqc" 2 / "Vtr1C" 0.65 "Ttr1C" 0.05 "Ftr1C" 0.1 "Vrc1C" 1 "Trc1C" 9999 / "Vtr2C" 0.6 "Ttr2C" 0.03 "Ftr2C" 0.1 "Vrc2C" 1 "Trc2C" 99999 / "LfmD" 1 "CompPF" 0.98 / "Vstall" 0.54 "Rstall" 0.1 "Xstall" 0.1 "Tstall" 0.03 "Frst" 0.14 "Vrst" 0.95 "Trst" 0.3 / "fuvr" 0.1 "vtr1" 0.6 "ttr1" 0.02 "vtr2" 0.9 "ttr2" 5 / "Vc1off" 0.5 "Vc2off" 0.6 "Vc1on" 0.4 "Vc2on" 0.5 / "Tth" 15 "Th1t" 0.7 "Th2t" 1.9 "tv" 0.025 Slide 41 41 Powerflow case (done by SRWG) Climate zone and load type are identified in Long_ID column of load table in PSLF E.g. DSW_RES = Desert Southwest, predominantly residential loads EPCL Programs (done by WECC Staff) Default data sets for each climate zone and feeder type Ability to over-ride defaults with specific information Creates composite load model records for PSLF PTI PSSE Users Convert from PSLF models IPLAN tolls may be available ? Load models will be distributed by WECC staff with study cases LMDT 3A is posted on WECC web-site, including users manual LMDT 3A Slide 42 Load Model Validation Studies Slide 43 August 4, 2000 Oscillation - CMPLDW Slide 44 August 4, 2000 Oscillation - MotorW Slide 45 August 4, 2000 Oscillation - CmpldW Default Data Set Slide 46 August 4, 2000 Oscillation - CmpldW Tuning Slide 47 June 14, 2004 Westwing Fault - CmpldW Slide 48 July 28, 2003 Hasayampa Fault Slide 49 July 28, 2009 Mid-Valley Fault Frequency Voltage Slide 50 System Impact Studies Slide 51 2011HS Chief Joseph Brake Blue = MotorW Red = CmpldW phase 1 Green = CmpldW phase 2 Slide 52 2011HS BC-Alberta Loss (546 MW) Blue = MotorW Red = CmpldW phase 1 Green = CmpldW phase 2 Slide 53 2011HS 2 Palo Verde Outage Blue = MotorW Red = CmpldW phase 1 Green = CmpldW phase 2 Slide 54 2011HS 2 Palo Verde Outage Blue = MotorW Red = CmpldW phase 1 Green = CmpldW phase 2 Slide 55 2014LS Montana Blue = MotorW, 77% dip Green = CmpldW, 22:00, 82% dip Brown = CmpldW, 6:00, 82% dip Slide 56 2014LS Montana Blue = MotorW Red = CmpldW, Grey/Green = CmpldW, improved exciters at a hydro plant Slide 57 Next Steps Slide 58 Conclusions WECC Composite load model is implemented in GE PSLF, Siemens PTI PSSE, Power World, Power Tech TSAT Tools are developed for load model data management Default sets are developed: 12 climate zones in WECC, four types of feeders Summer, winter and shoulder conditions Slide 59 Conclusions Validation studies are done for FIDVR events and oscillations System impact studies Significant impact on faults in large load centers FIDVR Impact on inter-area oscillations Slide 60 FIDVR Composite load model is capable of reproducing the FIDVR phenomenon Composite load model can be tuned with reasonable data sets to match the historic events MVWG at this point is not comfortable recommending using CMPLDW for FIDVR studies for compliance purposes There is a concern that the FIDVR modeling can result in over- investment or unnecessary operational restrictions Slide 61 FIDVR Planned Work Continue work on understanding the phenomenon of air-conditioner stalling in distribution systems (supported by DOE) Work with AHRI Feeder simulations Speed up efforts on collecting disturbance recordings SCE, SRP, Center Point Energy, PSE, BPA/PGE A letter was sent to grid operators in the East Tools for detecting FIDVR events in PMU data Slide 62 CMPLDW Phased Approach Slide 63 CMPLDW CMPLDW has many benefits beyond FIDVR TSS delayed PSS Policy review until appropriate load models are developed Frequency response review studies are required Slide 64 CMPLDW Plan Today Approve the implementation plan for adopting Phase 1 CMPLDW for system studies Continue improvement of FIDVR modeling Disturbance recordings, system impact studies Start using the CMPLDW for studies to support the review of the WECC voltage dip criteria Seek the approval of the CMLDW with FIDVR enabled and the new reliability criteria by Fall 2012 Slide 65 Motion Approve the implementation plant for replacing the interim load model with a Phase 1 composite load model Use default data sets Residential air-conditioner stalling disabled* * No revision of the WECC reliability criteria is needed