Energy saving opportunities - Communication and information systems
From Electrical Installation Guide
Contents |
Information systems
Whether it relates to measurements, operating statuses or rate bases, raw data can only be useful when converted into usable information and distributed on a need-to-know basis to all those involved in energy efficiency with a view to improving the expertise of all participants in the energy management process. Data must also be explained, as people can only develop the management and intervention skills integral to any effective energy saving policy if they fully understand the issues involved. Data distribution must produce actions, and these actions will have to continue if energy efficiency is to be sustained (see Fig. K19).
However, this cycle of operations requires an effective communication network to be in place.
Fig. K17: Operating cycle for data essential to energy efficiency
The information system can then be used on a daily basis by the operators at the various locations where electricity is consumed (for industrial processes, lighting, air conditioning, and so on) to achieve the energy efficiency objectives specified by company management. It can also ensure these same locations make a positive contribution to company operations (in terms of product volumes, conditions for supermarket shoppers, temperatures in cold rooms, etc.).
Monitoring systems
- For quick audits which can be performed on an ongoing basis.
Encouraging familiarity with data and distributing it can help keep everything up to date, but electrical networks develop rapidly and are permanently raising questions about their ability to cope with such new developments.
With this in mind, a system for monitoring the transfer and consumption of energy is able to provide all the information needed to carry out a full audit of the site. As well as electricity, this audit would cover water, air, gas and steam.
Measurements, comparative analyses and standardised energy consumption data can be used to determine the efficiency of processes and industrial installations.
- For rapid, informed decision making
Suitable action plans can be implemented. These include control and automation systems for lighting and buildings, variable speed drives, process automation, etc.
Recording information on effective equipment use makes it possible to determine accurately the available capacity on the network or a transformer and to establish how and when maintenance work should be performed (ensuring measures are taken neither too soon nor too late).
Communication networks
Information and monitoring systems are synonymous with both intranet and Internet communication networks, with exchanges taking place within computer architectures designed on a user-specific basis.
- Intranet
For the most part, data exchange in the industrial sector uses Web technologies permanently installed on the company’s communications network, typically an intranet network for the sole use of the operator.
As far as industrial data exchange between systems connected via a physical transmission link, such as RS485 and modem (GSM, radio, etc.), is concerned, the Modbus protocol is very widely used with metering and protection devices for electrical networks. Initially created by Schneider Electric, this is now a standard protocol.
In practice, electrical data is recorded on industrial Web servers installed in enclosures. The popular TCP/IP standard protocol is used for transmitting this data in order to reduce the ongoing maintenance costs associated with any computer network. This same principle is used by Schneider Electric to communicate data associated with promoting energy efficiency. No additional software is needed – a PC with an Internet browser is all that is required. The fact that enclosures are autonomous removes the need for an additional computer system. As such, all energy efficiency data is recorded and can be communicated in the usual manner via intranet networks, GSM, fixed telephony, etc
- Internet
Remote monitoring and control improve data availability and accessibility, whilst offering greater flexibility in terms of servicing. Figure K18 shows a diagram of this type of installation. Connection to a server and a standard Web browser makes it much easier to use data and export it to Microsoft Excel™ spreadsheets for the purpose of tracing power curves in real time.
Fig. K18: Example of an intranet information network protected by a server (EGX400 – Schneider Electric) and monitored from the Internet network
- Architectures
Historically and for many years, monitoring and control systems were centralised and based on SCADA automation systems (Supervisory Control And Data Acquisition).
These days, a distinction is made between three architecture levels (see Fig.19 ).
- Level 1 architecture
Thanks to the new capabilities associated with Web technology, recent times have witnessed the development of a new concept for intelligent equipment. This equipment can be used at a basic level within the range of monitoring systems, offering access to information on electricity throughout the site. Internet access can also be arranged for all services outside the site.
- Level 2 architecture
This system has been specifically designed for electricians and adapted to meet the demands of electrical networks.
This architecture is based on a centralised monitoring system designed to satisfy all the monitoring requirements for the electrical network. As might be expected, installation and maintenance work requires less expertise than for Level 3, since all the electrical distribution devices are already contained in a specialised library. In addition, acquisition costs can be kept to a minimum, as there are few requirements in terms of system integration.
Level 2 and Level 3 can be used side by side at certain sites.
- Level 3 architecture
Investment in this type of system is usually restricted to top-of-the-range facilities consuming large amounts of energy or using equipment which is highly sensitive to variations in energy quality and has high demands in terms of electricity availability. To ensure these high demands for availability are met, the system often requires responsibility to be taken for installation components as soon as the first fault occurs. This should be done in a transparent manner (any impact should be clear). In view of the substantial front-end costs, the expertise required to implement the system correctly and the update costs generated as the network develops, potential investors may be deterred and they may require highly detailed prior analyses to be conducted.
Fig. K19: Layout of a monitoring system
