Yale Runback Local Area Protection Scheme Yale Runback LAPS WECC RAS Reliability Subcommittee Merwin Plant Merwin Switch Yard Hydro Control Ctr Ariel Sub To Yale Plant Modification for the Yale Runback LAPS ID: 763180
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Yale Runback Local Area Protection Scheme Yale Runback LAPSWECC RAS Reliability Subcommittee Merwin Plant Merwin Switch Yard Hydro Control Ctr. Ariel Sub To Yale Plant
Modification for the Yale Runback LAPS Goodhope NwankpaProtection & ControlPacifiCorp WECC Remedial Action Scheme Reliability Subcommittee November, 2017 Salt Lake City, Utah
Merwin and Yale Hydroelectric Plants are located in SW Washington on the Lewis River Yale Plant is connected to Merwin Switch Yard via a 115 kV radial line Power is supplied to the grid via three115 kV linesTo BPA Cardwell to North – on to Lexington & LongviewTo CPUD Cherry Grove to South – on to Portland System To Cowlitz PUD/Lewis River Line – between Merwin SS and Lewis River Substation Plants started in 1929, last major addition 1958Performance and control upgrades only after 1958 Overview
Merwin and Yale Plant Vicinity Merwin Plant Yale Plant
Addition of new breakers Two new breakers were added to each lineAddition of a new lineCowlitz PUD/Lewis River Line – between Merwin SS and Lewis River Substation What Changed?
Simplified System One Line (old)
Simplified System One Line (New)
Previous Scheme11A & 11B relays monitored Kalama (Longview) and Battleground (Portland) lines and if any one of the lines are overloaded, run back is initiated and if after 60 seconds line overload is not cleared, Yale line breakers (2P26 & 2P27) are tripped. How Do Changes Affect LAPS?
Present Scheme11A & 11B relays monitor Battleground (Portland), Lewis River and Kalama (Longview) lines and if any one of the three lines are overloaded, run back is initiated and if after 60 seconds line overload is not cleared, Yale line breakers (2P26 & 2P27) are tripped. How Do Changes Affect LAPS
Description of the Problem Maximum Generation OutputMerwin Plant 144 MWYale Plant 170 MWCombined Total 314 MW 4 Hour Emergency Summer Line RatingsMerwin to Cardwell 177 MVA Merwin to Cherry Grove 176 MVAMerwin to Lewis River 175 MVAIf two lines trip, the other one overloads NERC TPL – 002 Violation90 Seconds to respond before line clearance problem Max Merwin output is less than the three line rating
Proposed Solution Modify an existing automatic run back scheme for the Yale Hydro Plant Located at Merwin Switch Yard and Plant Redundant relays monitor the three out going lines for overload If a non-transient overload is detected (120 cycle delay) Signal Hydro Control via Modbus to automatically run back the Yale Plant until the line is within the 4 hour rating If the automatic run back does not work within 60 seconds Trip the radial transmission line to Yale at Merwin end Reliability All controls local to Merwin control house CT circuits and relays are redundant Line trip with delay is hardwired at Merwin control house Independent from Hydro Control system that operates the Yale Run Back Scheme.
Why Yale and not Merwin Merwin Plant regulates downstream river flowNeed to keep at least one unit on line at all timesMerwin maximum output is less than the rating of any of the three linesYale maximum output exceeds steady state line ratingBackup line trip does shed CPUD Chelatchie distribution substation Easy restore by SCADA after Yale Plant trips off line
Qualifies as a Local Area Protection Scheme because: Load loss is limited to 11 MW (at Chelatchie substation) which is less than the 300 MW limitMaximum generation loss is limited to 170 MW for the Yale Plant which is less than the 1000 MW limitInadvertent operation would NOT result in a TPL–001 thru TPL-004 violation, including WECC-1-CR System Performance CriteriaThe scheme is fully redundant, failure of a single component cannot cause the scheme to fail to operate The scheme will only affect PacifiCorp owned and operated lines and generation, directly connected to the Merwin Switchyard Classification as a LAPS
Failure of any component will not result in a TPL 1-3 violation. Failure of the runback would result in a trip of the Yale Plant and Chelatchie substationInadvertent operation would not result in a TPL 1-3 violation.Inadvertent operation would result in a temporary loss of generation at the Yale PlantThe proposed scheme will coordinate with and not affect the related protection and control systemsCompliant with RAS Criterion WR5.1-3
Yale Runback Technical Details Q & A
Merwin Switchyard One-Line
Kalama (Longview) One Line
Battleground (Portland) One Line
Lewis River One Line
Merwin Plant and Switchyard
Merwin and Yale Area
Merwin Switchyard
BPA Cardwell Substation
CPUD Cherry Grove Substation