SBSA Rosebank is a multistory office block development on the corners of Cradock and Bolton Roads and is just opposite the Rosebank Mall.
The main contractor is WBHO Construction and the architect is GLH & Associates with a multitude of sub-contractors working on this site.
The system installation at Rosebank comprises of 5 x 1650kVA rotary UPS systems generating at 11kV with provision for installation of 2 more units feeding the data centre. The emergency auxiliary supply is provided by 1 x 1650kVA diesel generator set running at 400V. The system is designed to run N + 1.
The installation include the following equipment:
In normal mode, when the mains is within tolerances, the synchronous machine is acting as a synchronous motor, driving the kinetic energy accumulator and storing kinetic energy in it.
In emergency mode, on mains failure or voltage perturbations, the stored kinetic energy is retrieved and transferred to the synchronous machine, which is now acting as a generator. This occurs without any interruption to the user.
Shortly after mains failure, the diesel engine is started and coupled to the synchronous machine by closing the electromagnetic clutch. The energy is then provided to the synchronous generator by the diesel engine for unlimited time.
How is kinetic energy stored?
The inner rotor, driven by the central shaft, rotates at 1500 rpm (50Hz) or 1800 rpm (60Hz). It is provided with two sets of windings: a three phase AC winding and a DC winding.
In normal mode, the AC winding is energized to generate a rotating magnetic field which accelerates the outer rotor to approximately 3000 rpm. Nevertheless, the relative speed between inner and outer ring of the bearings is only 1500 rpm since the shaft itself is rotating at 1500 rpm.
The outer rotor (accu-rotor) stores kinetic energy advantageously, since the amount of kinetic energy increases quadratically with the distance from the center of rotation.
In emergency mode, the DC winding is energized and the outer rotor is coupled to the inner rotor by induction. Its kinetic energy is transferred to the inner rotor: it drives it. This energy transfer is regulated by controlling accurately the current injected into the DC winding. The stato- alternator is a totally brushless machine.
SSPD will be supplying the engine and alternator for the 1650kVA standby generator.
MSD will supply the MV Switchgear for the generator/UPS plantroom, Consumer MV sub-station and the Council MV sub-station.
This project was sold by Annedine Ryan and Susan Visser is the Contracts Engineer.
Tinus Roberts and his team have already started with the mechanical installation and more teams will move onto site as the installation progresses.
Carlos Pereira will be in charge of the electrical installation.
We have to comply with very stringent “Health and Safety” requirements.
The client is insisting on the enforcement of all health and safety and there is a “zero tolerance” attitude towards health and safety on the site.
We are all looking forward to the safe and success completion of project towards the end of 2011.