Load Management Projects at the Department of Water Affairs through an

Integrated Systems Approach

Chris Scheepers15 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

WorkUpgrades 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.