WSP05148 - Laserfiche WebLink

Home Browse Search

'" ~ ~~ ;j! usbr/wapa ..~ magnitude, the average of which approximates the original schedule. .. /.; "" Emergency Exception Criteria vs. Regulation Both emergency exception criteria and regulation have been described in this paper. Recently, some members of the AMWG and TWG have focused their concerns and discussion on "emergencies". However, the issue at hand and the subject of this paper is regulation. [t is largely regulation that has resulted in the occasional exceedence of the 1,500 cfs downramp. Ie :~ (i '-j ':;:t '.', V. Measurin~ Compliance & Measuring Devices :or- ,j. ~~ ,~ ~ Xl l1:. ; The target values set in the SCADA are usually not exactly achieved. Moreover, the water released from the dam is not precisely measurable. The reasons for this are explained below. Measuring Devices "'.- I,:. As per the ROD, the SCADA system is the official means of reporting flow conditions at Glen Canyon. There are currently two methods by which water passing through the power plant at Glen Canyon is measured and reported to SCADA.: ,..:" Turbine ratfug curves: The turbine curves describe the performance of the turbines and were used to develop a data base in the SCADA system at Glen Canyon for reporting operations and water releases. The use of the SCADA system for reporting water flow was the method in place at the time the ROD was implemented. The turbine rating cUrves were derived from testing the turbines and generators and take into account the number of megawatts being generated, the amount of head, and the unit efficiency. The turbine curves are considered to be accurate to within :1:3%. Frequent periodic samples are taken on the amount of generation, and the results are converted and integrated by the SCADA system, into an hourly flow number in (cfs). .~.'~"; ';"-" . ;.~, >1 :r." ';:.1 ',. \!-. Accusonic Flowmeters: Each generator penstock has several transducers attached to them to measure the actual instantaneous flow through that penstock. The flow meters are considered to be accurate to within 1% when reporting directly to the Accusonic recording instrument. The flows from all penstocks are sampled every 15 seconds, accumulated by the flowmeter computer and then averaged to show what the flow has been over the last hour. ~I ;~:;; I, ".. {.:" -:'.. This average is also fed to the SCADA system. To condition the signal from the Accusonic flowmeters for use/input to the SCADA system, the accuracy is considered to be about :1:3%. Presently, these flowmeters are not being used as the official method of 5