Performance evaluation of pressure reducing valves using statistical approach in water distribution system

Abstract

A pressure-reducing valve (PRV) regulates the outlet pressure regardless of the fluctuating flow and varying inlet pressure, thereby reducing leakage and mitigating the stress on the water distribution system. However, the operation of a PRV is affected by its mechanical condition and hydraulic operability. In this study, a statistical approach is proposed to assess the performance of a PRV by extracting hydraulic pressure noise from pressure data, and applying it to metered areas in the Goseong and Sungeuiwon districts of Goseong city. The proposed approach involves the application of Walsh’s test to detect outliers in the pressure data at a significance level of 5%. The experimental results using field data showed that all measured data items were valid. A high-pass filter was then employed to extract white noise from the original pressure data for 24 h. The noise from standard PRVs remained relatively stable over time, ranging approximately ±0.2 kgf/cm², and the noise was found to be independent of the weighting parameter. On the other hand, it was found that noise from an abnormally operated PRV exceeded ±0.2 kgf/cm², with the magnitude of the scattering being proportional to the weighting parameter. The field test results show that the proposed approach is effective for assessing the performance of PRVs using a simple pressure measurement, an outlier test, and a noise filter.

Keywords:

• Pressure-reducing valve
• Water distribution system
• Statistical approach
• Walsh’s test
• Noise filtering
• Outlier test

Acknowledgments

This research was supported by the Korea Ministry of Environment under “The Eco-Innovation Project (Global Top Project)” No. GT-SWS-11-02-007-8, and the Korea Water Resources Corporation (K-water).

Notes

Presented at the 6th IWA-ASPIRE Conference & Exhibition, Beijing, China, 20–24 September 2015