Sewer Pump ON/OFF as Synthesized Flow Meters

Transcription

1 Innovyze Gold Coast User Group Conference Sewer Pump ON/OFF as Synthesized Flow Meters 11 October 2016 Ian McDonald

2 Introduction This presentation investigates an alternative method to determine pump rates using Supervisory Control And Data Acquisition (SCADA) telemetry data. It has analysed 71 pump stations in Loganholme WWTP catchment and compared pump rates from draw-down tests versus calculated 2015 SCADA pump rates.

3 Loganholme WWTP Catchment - Comparison of Draw-Down Test Results vs 2015 SCADA Pump Rates Project Results A total of 57 out of 71 pump stations completed 2015 SCADA test analysis. The results found: 21% reasonable correlation 25% SCADA under-estimating flow rate 16% SCADA over-estimating flow rate 38% missing data General Observations 26 pump stations showed large variations (over 10%) between P1 and P2 pump durations. Of these, 12 have known reasons such as different pump type, age of pump or impeller diameter size. 29 pump stations showed large variations (over 10%) between previous pump draw-down tests and 2015 SCADA pump rates Previous draw-down tests may not have followed correct testing procedure Missing data included: No current draw-down test Missing 0% and 100% SCADA levels or wet well dimensions One pump station is not connected to SCADA A number of recent improvements have been identified to be discussed in the following sections

4 Standard Procedure to Determine Pump Rates Start pump at high level to account for soft start Average between ON and OFF Transducer 0% DESIRABLE TEST RANGE Constant cross-sectional area Middle of Min/Max levels Min depth 300mm, preferably 500mm Below all incoming pipes Above pumps Above wet well benching

5 Improve Data Collection Obtain Wet Well Dimension and Benching Details 3D Laser Scan SPS106 Convert Wet Well to Storage Type Node Note: All pump stations in Loganholme WWTP catchment are now scanned. Currently awaiting conversion to as-constructed drawings SPS18

6 Improve Data Collection - Calculate Operating Volume in Sewer Network Between Switch ON/OFF Infoworks Storage Calculation Manhole = m3 Pipes = m3 Total = m3 Note: Also need to account for DWF flow volume in pipes and manholes ON OFF

7 Improve Data Collection Check SCADA Pump Settings and Switch ON/OFF Data Switch ON/OFF levels Note: Ensure correct operating level used in calculation of SCADA pump rates Pump Soft Start Time Data Clean-up Add missing P2 switch OFF Note: Reduce the average pump runtimes by approx. 50% to account for loss in volume during soft start of pumps

8 Check Pump Performance using Pump Run Time Graphs Pump Results during DWF period (16d) 27/07/2015 to 11/08/2015 Pump P1 P2 Average Pump Runtime 5 min 55 sec 6 min 25 sec 6 min 10 sec

9 Coral Street SPS Calibration Study (2014) Arline Street SPS Pump Runtime Pump Rate Test Pump 1 Pump 2 P1 + P Draw-Down Test (L/s) Draw-Down Test (L/s) SCADA Calculation (L/s)

10 Example to Determine Duty Assist Pump Rate Good correlation in results

11 General: Summary Of the 71 pump stations reviewed, 21% showed good correlation with draw-down tests Future analysis in 2016 should include outstanding details identified (eg, insert 3D laser benching details). It is also recommended to obtain missing pump station details, redo old draw-down tests and re-survey 0% and 100% SCADA levels. Following verification of SCADA pump rates at each pump station, then future draw-down tests may not be required Limitations: Good quality asset information is essential; e.g. wet well dimensions, soft start times, pump operation levels (including SCADA 0% and 100%), upstream network pipe invert levels, etc. Requires an accurate log of maintenance changes to pumps and control settings VSD or injector pump stations are not able to be analysed using this methodology Some pump stations are very old and parts have been replaced, meaning the manufacturer s curves may not apply Benefits: Pump runtime graphs can highlight poor pump performance due to pumps/valves ragging, high infiltration or when one pump is under performing Historical pump rates can be determined from past SCADA records This approach has improved our knowledge of pump stations without flow meters Able to calculate pump rates at pump stations with low lying incoming pipes, benching and varying wet well cross sectional areas Confidence that pump rates are obtained at the correct operating levels (unlike some draw-down tests) Able to calculate ADWF and baseflow