The Installation

The computer centre is located in an large special purpose building, of which several thousand square metres are given over to computer rooms in the strict sense with the same floor space being used for technical services for the associated systems:

• an incoming mains substation with several 1 300 kVA transformers

• a standby power supply consisting of generator sets providing 4 000 kVA power

• a group of 50 and 400 Hz inverters

• a backup battery supply sufficiently autonomous to take over when the supply changes

• a cold water station with four 350 kVA refrigeration compressor units

• 40 air conditioning units divided into two independent circuits in the computer rooms, providing a total air flow of 820 000 m³ per hour.

The Problem

The computer centre must be operational 24 hours a day, which implies:

• continuous adaptation of energy consumption to the needs by load shedding and reconnecting

• severe constraints of temperature and hygrometry control for the computer air conditioning

• continuous monitoring of the installation : data acquisition from alarms, sensors, analogue measurement devices, as well as all of the information needed for the short term functioning and for preventive maintenance.

The Solution

This consists of adopting an automated production type of architecture, divided functionally into different levels :

• at level 0 the sensors and actuators with the use, notably, of Integral 32 contactor breakers

• at level 1, the local automatic control systems (distribution boards, standby generator sets, refrigeration units...) are controlled autonomously by more than 10 TSX series 7 PCs. The inter PC communication is provided by a Telway 7 network, which thus enables the coordination of the level 1 systems. Man-machine dialogue for this level is provided by XBT microterminals, an alpha-numerical keyboard with VDU, and two printers

• at level 2, a supervisory system comprising a central programmable controller edits the data as it arrives and permits the acquisition of the operating reference values. This PC is linked with both the level 1 PCs and with the Monitor 77 supervisor.

Centralised supervision Remote surveillance

The control and supervision of the complete system is carried out by a Monitor 77, whose main functions are: animated synoptic display of the various parts of the installation, follow up of curves, storage of events. This covers more than 2 000 discrete states and 250 analogue measurements. The computer centre can be continuously remotely monitored from the UAP headquarters at La Defense in Paris via a special telephone link.

Outside normal working hours, surveillance can be carried out from a local surveillance point using the automatically switched telephone network.

Like this, it is possible for authorised personnel to undertake any rapid interventions which might be necessary via a standard telephone line terminal.

Text 6

Automation of a Micro Hydroelectric Power Station

Energy production at a competitive price was the target for Forces Motrices du Foron, an industrial partner of the French Electricity Board, using the micro hydroelectric power station at Scionzier, near Cluses in the Haute-Savoie area of France. Added to this, the updating of the medium voltage part provided the opportunity to automate the installation to 100%.

For this, Etablissements Hennequin, main contractors for the new installation, called on the services of Telemecanique both in deciding which hardware to install, and to help write the software. A single TSX 47 programmable controller enables the simultaneous control of the process and communication management via an XBT dialogue terminal.

Remote monitoring, by standard telephone line terminal in addition to a complete video circuit supervision system of strategic points, makes the installation particularly comfortable to use.

The Micro Power Station

The standard hydroelectric installation for an average size mountain waterfall consists of a dam, a penstock pipeline, and a power station. A wasteway raises the upstream waterlevel and diverts the flow via a lateral adduction channel to a 300 m³ feeding chamber. Two grids at the opening of the channel and chamber are kept constantly immersed. This makes it possible to limit, particularly during winter at low water marks, any freezing or clogging by floating twigs and sticks which might occur, necessitating cleaning with motorised grill cleaners. The penstock pipe, 1800 m long, supplies the power station, located 200 m below, at 20 bars. A Pelton turbine drives a 650 kW, asynchronous, 5,5 kV generator at 750 rpm. Operating in hypersynchronous mode, the generator supplies the French Electricity Board system with active power and absorbs the reactive power supplied by a bank of capacitors. A 5,5/20kV medium voltage station connects the installation to the grid network.

If anything untoward should occur with the turbine or the generator, such as running away, following the tripping of a downstream circuit breaker, it is necessary to bring the machine to an immediate stop. A deflector stops the water working on the buckets without entirely cutting the water flow, which would cause a pressure surge unacceptably harsh for the pipe. The injector needle is then gradually closed. Continuity of water distribution downstream is then ensured by a restoration pipe, by-passing the turbine.