CEMS data validation analysis
- Niagara Mohawk Power Corp., Syracuse, NY (United States)
Niagara Mohawk Power Corporation (NMPC) validates all the CEMS data in the EPA Part 75 report before submittal. Data validation refers to acceptance and documentation of the data. Acceptable data are accurate and representative. Trend analysis is used primarily to review the data for accuracy, i.e., to exclude potential instrument problems. Outlier analysis is also used to check accuracy but primarily documents the data for future analyses. NMPC`s data validation emphasizes analysis of the reportable hourly data. Once data collected by the Environmental Systems Corporation polling computer have been initially accepted, the data are downloaded into STATGRAPHICS Plus for Windows{copyright} (Manugistics, Inc., Rockville, MD) for review and analysis. The trend analysis uses plots to determine if there was a change in the measured values over time. Plots of the hourly sulfur dioxide mass emissions, nitrogen oxide emission rate, carbon dioxide concentration or flow rate against load are generated. STATGRAPHICS Plus for Windows{copyright} includes a feature which allows the analyst to change the color of the plotted points as a function of time. If the relationship between the measured value and load changes over time, there is potential for an instrument problem. Those periods are reviewed in detail. The outlier analysis uses both plots and reports to determine hours where there might be problems. Although instrument problems can be recognized, more likely are periods when the data are not representative of the whole distribution. STATGRAPHICS Plus for Windows{copyright} generates a table that lists all the hours in which there are unusual residuals in the distribution of a regression between the measured parameter and load. Outliers on the plots are also checked. The results of both analyses are filed to document data quality. If necessary, results are also included with the data submittals to EPA.
- OSTI ID:
- 617889
- Report Number(s):
- CONF-970145-; TRN: 98:002057-0058
- Resource Relation:
- Conference: 2. joint conference on acid rain and electric utilities, Scottsdale, AZ (United States), 20-22 Jan 1997; Other Information: PBD: 1997; Related Information: Is Part Of Acid rain & electric utilities II; PB: 1047 p.
- Country of Publication:
- United States
- Language:
- English
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