LYONNAISE des EAUX : network control

A decentralized architecture to manage safely 685 sites delivering drinkable water to one million consumers: over 20 TOPKAPI server stations and dozens of operator stations (specialized or Web) for 56,000 basic items of information.

All operational centers at Lyonnaise des Eaux and its subsidiaries for Paris South ensure the production and distribution of water for about 1 million consumers.
685 technical sites are used for this task, from basic reservoirs to ultramodern treatment plants.
Controlling and driving the facilities is performed from 16 autonomously driven subcentres, coordinated by the remote control center in Montgeron.

The latter ensures production sequencing and distribution of drinkable water, as well as collection and processing of sewage. It manages the allocation of resources, while ensuring there is a satisfactory safety margin at all times to guarantee service continuity (reservoir levels, availability of production resources, quality monitoring).

Safety requirements have played a major part in the design of the system architecture, and in selecting reliable components: it must be able to produce water in sufficient quantity and quality at all times, while reducing vulnerability to major accidental failures.

Each of the 16 subcentres has one or several TOPKAPI server stations, with an application configured according to local driving requirements and processes the data sent by:

	local process programmable controllers
	remote sites (reservoirs, wells, pumping stations, etc.) fitted with remote management controllers
	remote sites fitted with "satellite" TOPKAPI driving stations, such as for example water quality analysis stations.

Each subcentre is connected to the control center in Montgeron by a 64 kbps Transfix link carrying the information exchanged by the controllers (controls and data required for local automation) and between TOPKAPI stations:

	the permanent information issued by TOPKAPI local servers required for the consolidation application in Montgeron, transmitted over a status variation (exception)
	information required for the display of the multiserver alarm summary views
	the information required for display when a TOPKAPI station opens the application of another centre as a client.

In addition to optimizing data exchanges over Transfix links, the full use of the operation in client/server of TOPKAPI provides the following benefits:

	driving information is configured only once, in the subcentre application
	any TOPKAPI station, whether a server or a simple client, has access to all the servers connected to the network, without any local configuration
	modifications within a plant induce modifications only in the subcentre application (modification unicity), except when they also concern the consolidation application of the Montgeron centre, which is rare.

The subcentres all have at least one server station used for operating and, according to the case, additional or backup server stations, client stations for operation, local or remote (modem or Intranet), Web servers providing access using Internet Explorer.

The Montgeron center has over 10 stations, including two redundant servers with OPC Applicom servers, a trends server for screen panels, a server for the Emeraude optimization software, and the various operating and summary stations.

For Jean-Marc PONTE, head of the production division and Michel LHOMME, in charge of the automation cell, the architecture implemented meets the very high requirements of Lyonnaise des Eaux in terms of system safety:

	information processing is decentralized, close to the field
	the central application concentrates only minimum processing and is easy to maintain
	the Transfix client/server links between TOPKAPI stations can be backed up using telephone network connections
	in case of a major crisis (e.g. fire), only the unit concerned is impacted ; even when the crisis impacts the control room of a subcentre, another TOPKAPI station can substitute, remotely, to the station concerned.

Jean-Marc PONTE notes with satisfaction that the recent implementation of the Web servers was fast and offers high operating flexibility.

AREAL wishes to thank all Lyonnaise des Eaux staff who brought their know-how on this project and others, and who helped TOPKAPI evolve by expressing their needs.