The computer hardware cabinets contain the minimum operable configuration of a computer system that controlled the distribution of high voltage electricity through NSW, Australia between 1985 and 2003. Transgrid, the organisation that donated these cabinets, oversees and coordinates high-voltage electricity transmission in New South Wales. They are one of the companies that were formed to take over the duties of the former State Electricity Commission.

The TOSBAC Series 7/70E System, of which these cabinets form a part, is a Supervisory Control and Data Acquisition (SCADA) system designed and marketed by Toshiba. It runs TREX 2 (Toshiba Real-time EXecution) which is a special operating system for SCADA. While the TOSBAC and TREX comprise a computer system designed for general control application, this system was especially commissioned to run the State electricity grid in NSW. It was purchased in 1982 and was running by 1985.

DAC, (Data Acquisition and Control) as it is known by the Transgrid engineers who operate the system, is the third computer system to have been used to control the grid. The first was an analogue computer from Leeds and Northrop called 'George' which was installed in the mid 1960s, and the second system was a PDP/11 called 'Little George' which ran from 1978 to 1985/6 when DAC was brought on line. The TOSBAC system illustrates the use of computers to implement sophisticated control of a major public utility, and the importance of computer systems to our technological infrastructure. It was still in use up until 2003 and had been controlling NSW's high-tension transmission for the better part of twenty years.

Prior to the grid being set up, power stations had to be built at the site of the power requirement. For example the Powerhouse Museum currently resides in the former power station built to supply electricity to Sydney's tram system. The understanding of power transmission has had implications for computing history. American scientist and engineer Vannevar Bush built his famous differential analysers in order to perform the calculations necessary to understand the behaviour of transient signals in electricity transmission lines. Moreover, this computer system represents an essential aspect of industrial and technological practice: control. From the governors used with industrial steam engines in the 1800s through to the operating system on personal computers, all technology requires a control system. Electricity is one of the most valuable and volatile elements of modern life. A highly sophisticated and reliable method of control is required to enable the safe delivery of electricity. The TOSBAC system is a significant example of a control system designed to manage an often unpredictable but essential commodity.

Damian McDonald
October 2007

The computer hardware cabinets were manufactured by the Toshiba Corporation in Japan, 1983.

Toshiba was formed in 1939 with the merger of two companies: Shibaura Engineering Works and Tokyo Electric. The merged company - Tokyo Shibaura Denki - was nicknamed Toshiba, and in 1984 the company was officially renamed the Toshiba Corporation.

Tosbac and Trex (operating system) were designed by Toshiba as a general SCADA computer system.

These cabinets were assembled as a minimum operable configuration from the system that was running at the Transgrid control rooms at Carlingford in Sydney, Australia.

Computer hardware cabinets (6), from TOSBAC (Toshiba Scientific and Business Computer) computer system, metal / plastic / electronic components, made by Toshiba Corporation, Tokyo, Japan, 1983, used by Transgrid NSW, Sydney, New South Wales, Australia, 1985-2003

The six computer hardware cabinets are of an aluminium outer construction with a cream coloured enameled finish. Although the cabinets appear similar, the components that the cabinets house perform different tasks.

The Training cabinet contains a simulation panel, twenty six removable circuit boards and a power supply with voltage meter. There are two manuals in the inside of the door of this cabinet.

The Monitor Panel cabinet contains a monitor with an analogue display and thirty two removable circuit boards. Attached to the inside of the door of the cabinet are four laminated A4 sheets with instructions on monitoring, and an unlaminated foolscap sheet with further handwritten instructions.

The Power Supply Unit cabinet contains the power supply distribution apparatus for the TOSBAC system.

The CPU 1 cabinet features a control panel rebated into the door. Inside it contains two power supply units, and sixty six removable circuit boards. There are three pages of handwritten log in the door.

The data tape cabinet features two reel to reel data capture systems - one above the other. The top system is for half hour snap shot data capture, the bottom system is for demand capture. The data tape is twenty four foot, 800 bits per inch tape.

The ARC 3 (Auxilury Relay Cabinet) contains a power supply, and a relay system .

Made: Toshiba Corporation; ; 1983

Training Cabinet: Type MAP10M20S; Production No 3601200, FK2764, Manufactured September 1983; The Electricity Commission of NSW Transmission Division No CA/D725

Monitor Panel: Type MAP10M20S; Production No 3601200, FK0752, FK0753; Manufactured September 1983; The Electricity Commission of NSW Transmission Division No CA/D707

Power Supply Unit: Model PSU8001A001; Serial Number PD7012; The Electricity Commission of NSW Transmission Division No CA/D736

1CPU1 Cabinet: Model PSU8001A001 and PSO317A001; Serial Number PD7052 and 7002

ARC 3 Cabinet: Product Number 3601200FK2664; Serial Number 8351153; Manufactured January 1983; The Electricity Commission of NSW Transmission Division No CA/D722

2008/58/1

1983

1800 mm

610 mm

810 mm