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Texas Nodal EMS & MMS AREVA & ERCOT Comments on Generation to be dispatched by SCED January 24, 2007 Sai Moorty MMS Project Engineer. AREVA (EMS Vendor ) Comments. Option 1 GTBD = ∑Genactual
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Texas Nodal EMS & MMSAREVA & ERCOT Comments on Generation to be dispatched by SCEDJanuary 24, 2007Sai MoortyMMS Project Engineer http://nodal.ercot.com 1
AREVA (EMS Vendor ) Comments • Option 1 GTBD = ∑Genactual • AREVA believes this does not do enough to help the system recover frequency deviations. The concern is that the system would always be 'behind' where it needs to be. • Option 2 GTBD = ∑Genactual + ∑NCLactual - ∑NCL30 min average + PSCED * LRR • High complexity. • The problem is not the NCL values, but the LRR value. • Many other systems have struggled to get a reliable calculation for LRR. For example, if this is just the average load rate over an hour, does that mean that recognition of the peak (load turn-around point) will be delayed by as much as half an hour? Then there is the issue of what to do with the near-term load swings. • Also, it is easier to implement to compare the current NCL with a filtered NCL. • Option3 (Alternative proposal by AREVA) GTBD = ∑Genactual + Frequency Recovery MW - (∑NCLactual - ∑NCLfiltered) • Frequency Recovery MW is load damping (DDf) component. • Addresses the points of concern and be much easier to implement/maintain. • This approach will provided the MW boost to address frequency deviation while not causing the system to swing to the other extreme when the nonconforming load swings. http://nodal.ercot.com 2
ERCOT Comments • Nodal EMS Project does not have Short Term Load Forecast. LRR calculation will be based on actuals. • Assumption that LMPs calculated by SCED is effective from the time SCED is executed till the time of next SCED execution. http://nodal.ercot.com 3