Load Management Projects at the Department of Water Affairs through an Integrated Systems Approach Chris Scheepers 15 August 2012

The Need for Water...  South Africa is divided into 19 water catchment areas.  Water is transferred to different areas and national key important instances. Usutu-Vaal water scheme Water needed for:  Agriculture  Municipalities  Power stations  Chemical processes (Sasol)  Mines

Usutu-Vaal Government Water Scheme (GWS) Standerton Secunda Matla PS

Pump Stations  Naauwpoort (Witbank);  Rietfontein (Secunda);  Grootfontein (Charl Cilliers);  Grootdraai and Tutuka (Standerton);  Geelhoudboom; (Between Morgenstond- and Heyshope dam) and  Heyshope (Piet Retief). Clients/Destinations  Duvha P/S (if needed)  Matla P/S (Kriel P/S)  Sasol and Rietfontein dam  Tutuka P/S and Grootfontein weir  Grootdraai- and Morgenstond dam  Geelhoutboom pump station Usutu-Vaal GWS Pump Station and Clients

Usutu-Vaal GWS Layout: Grootdraai (GD) Dam Supply  Grootdraai backup supply: Heyshope- and Geelhoutboom pump stations  Pump when GD is below minimum operating level (80%).  Usually during the winter/dry seasons.

Usutu-Vaal GWS Layout: Client Supply Installed Capacity  Tutuka (4x 1405 kW)  Grootdraai (4x 1650 kW)  Grootfontein (1x 2200 kW and 4x 2150kW)  Rietfontein (4x 3050 kW) Target savings 3.80 MW 3.15 MW 3.20 MW

Usutu-Vaal GWS: Previous Control Philosophy  Relay logic control panels were used.  Limited remote control.  Limited condition monitoring available.  Limited monitoring of dam/reservoir levels.  Time of use (TOU) not taken into account.  No data trending was available.

 Upgrade pumps to enable automatic control.  Upgrade centralise SCADA & include a REMS  Install additional communication infrastructure.  Monitor dam levels – GSM modems.  Control system to optimise load shifting potential. Load Shift Project: Usutu-Vaal GWS – Scope of Work Upgrades on Grootdraai, Grootfontein and Rietfontein:

Usutu-Vaal GWS: New Control Philosophy  PLC panels allowed for remote control.  Previous control philosophy was used.  Pump station control updated – communication between pumps.  Detailed conditioned monitoring.  Dam levels monitoring by GSM modems.  Integrated control philosophy between the pump stations.

Usutu-Vaal GWS: Introduced SCADA  New SCADA with condition monitoring.

Usutu-Vaal GWS: Integration of pump stations  Grootdraai (GD) pump into Vlakfontein Canal to Grootfontein: 24 hours with 1 GD pump 11-12` hours with 2 GD pumps  Grootfontein pump water from forebay to Knoppiesfontein towers.  Water may not be spilled at the Grootfontein weir. 41 km Vlakfontein canal

Usutu-Vaal GWS: Grootdraai Pump Station Results  Grootdraai pumps stopped at the following times: 07h00 to 09h00 – To ensure water ‘shortage’ at Grootfontein. 18h00 to 20h00 – Evening load shift.  Note: Tutuka pumps only stopped during evening peak.  Achieved load shift (3 months): 3.8 MW  103% performance. (Load shift for Grootdraai and Tutuka)

Usutu-Vaal GWS: Grootfontein Pump Station Results  The Grootfontein pumps were stopped: From 06h00 due to evening load shift at Grootdraai. 18h00 and 20h00 – Evening load shift.  Achieved load shift (3 months): 3.2 MW  107% performance.

Usutu-Vaal GWS: Rietfontein Pump Station Results  The Rietfontein pumps were only stopped during: 18h00 and 20h00 – Evening load shift.  Achieved load shift (3 months): 6.34 MW  198% performance.

Conclusion  Large electrical loads were shifted out of the evening peak. (Average 3 month total of 13.4 MW)  The supply to the clients was not compromised.  The control philosophy was revised and updated.  The control between pump stations was successfully integrated.  Advanced condition monitoring are done by the SCADA.  Control allows for most efficient pump combinations to be operated.  Remote access is possible for maintenance, control and support.  Pumps were refurbished - not included in the initial contract.