SBSA Rosebank

SBSA Rosebank

SBSA Rosebank

Posted on 28 September 2016

Project Overview

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.

DES Scope of Works

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:

  • 1 x 1650kVA Standby Generator
  • 5 x 1650kVA Rotary UPS’s
  • 5 x Step-up Transformers and associated MV Switchgear
  • 2 x 9000 Ltr. Day Tanks
  • 7 x 23000 Ltr. Bulk Fuel Tanks
  • 630kVA Auxiliary Transformer
  • Various control and change-over panels
  • Exhaust Systems
  • Sound Attenuation

More Information on the Rotary UPS Units

Operating modes

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.

Sister Company Involvement

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.

DES Team Work

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.

Health and Safety

We have to comply with very stringent “Health and Safety” requirements.

  • Nobody is allowed on site unless they have undergone the site induction.
  • Everybody has to undergo a medical examination and you have to present you medical certificates when you start working on site.
  • You are not allowed on site if you do not have the minimum required PPE.
  • Weekly “Toolbox Talks” must be done.
  • Monthly tool and equipment lists must be completed.
  • We are not allowed to erect scaffolding above 3.5m in height. This scaffolding must be erected by WBHO.
  • We have to attend monthly health and safety meetings.
  • Our health and safety file is audited by WBHO on a monthly basis.
  • WBHO’s (and sub-contractor’s) health and safety files are audited by the client on a regular basis.
  • Method Statements and Risk Assessments must be submitted before any work can commence on site.

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.