Radio teleswitch

Radio Teleswitching is the transmission of digital data on radio for alarm, control and information to locations throughout the reception area of the radio transmissions.

The idea of using existing national broadcasting infrastructure for sending teleswitching signals was considered back in 1964 and was originally primarily intended for load management, to enable the switching on of large numbers of night storage heaters and water heaters to be staggered to avoid sudden large increases in load as night rate systems cut in. More recently, it has been developed as a tariffing system.

There are thought to be in excess of 3 million RTS equipped meters in the field. However, the idea had to wait for technology to catch up with it and when this happened over a decade later, Radio Teleswitching began to emerge as a practical proposition. Following the successful conclusion of extensive trials which started in 1979, the relevant authorities approved Radio Teleswitching transmissions on the BBC’s national 198 kHz frequency radio broadcasts.

An important condition of the approval was that the radio teleswitching data should not impair the reception of BBC Radio 4 news and entertainment programmes normally transmitted on that long wave frequency. This was adequately demonstrated in the trials.

Fully operational Radio Teleswitching facilities became available in 1984. By being first in establishing Radio Teleswitching on a national scale as a fully operational, cost effective communication system for use in energy management, the electricity industry gave the UK a world lead in this field. The technique won the Queen’s Award for Technology.

The industry holds a patent on the development and issues licences to approved manufacturers of Radio Teleswitch receiver controllers. The devices are normally simple, competitive in price, highly reliable and capable of being locally or remotely controlled.

A unique feature and advantage of Radio Teleswitching is its ability to give authorised users instant, low cost access to a proven, nationwide, broadcast communication facility through nothing more than a PC and a modem. Users do not have all the problems associated with selecting, owning and operating complex communications infrastructures.

The flexibility of the system allows a range of load management, demand side management and other control strategies to be deployed. Load management applications have included the matching and co-ordination of generation and plant loading with customer demand for smaller isolated power systems.

For larger, more complex systems, it permits a wider selection of tariffs with more dynamic control for influencing energy consumption patterns and system loadings more precisely. This can make it easier to optimise economic margins, defer capital investment and accommodate operational constraints.

In recognition of both the technical innovation and the potential economic benefit it could bring the system received the Queen’s Award for Technological Achievement in 1987.

The system basically comprises user terminals and modems, the central teleswitch control unit (CTCU) the LF Data System, the 198kHz BBC Radio Four transmission system and radio teleswitching receiver controllers (RCs).

Each user of the system, the electricity distribution networks operators and electricity transmission network operator has a unique set of codes enabling them to address only their own block of meters and switches.

These instructions are sent by the network operators to the Central Teleswitch Control Unit (CTCU) housed and maintained by Cygnet Solutions.

The CTCU processes and forwards their switching codes to the BBC Message Assembler at Crystal Palace.

Here, the electricity industry codes are combined with the instructions from other users of the service and sent to the three national networks of transmitters. The main transmitter at Droitwich (see also the BBC site), rated at 500kW, can reach most parts of the UK and some parts of continental Europe while the two smaller transmitters located at Westerglen and Burghead cover Scotland and Northern Ireland.

At present, it is understood that the only other user of the system is the Environment Agency who use the system to disseminate flood warnings. Messages are encoded onto the Amplitude Modulated (AM) Radio 4 signal using Phase Shift Keying (PSK) techniques.

30 messages are transmitted per minute, each message having 50 bits of data. 18 of these bits are taken up by a BBC header and Cyclic Redundancy Check (CRC) tail. 32 bits are available for data.

The RadioTeleswitch specification (BS7647) lays down specific formats for its user message contents. Two message types are defined:

• command (or immediate) which has priority of broadcast, and on receipt immediately sets a Teleswitch (RCs) internal switches to required status, overriding any programmed status;
• programme, which updates or refreshes the operating program stored within a Teleswitch (i.e. internal switches will not change status until required by the program).

An ‘immediate’ instruction can take one or two minutes from initiation of a request at the terminal of a user, depending on other traffic on the data system, and is intended to allow fast, broadcast load shedding.

The system’s ability to offer users both programmed and immediate broadcast control have enabled companies using the system to provide weather-related control of electricity storage heaters in specialised arrangements such as ‘budget warmth’ and ‘heat with rent’ schemes.

The transmission of cost reflective messages and weather forecast information has allowed the concept of controlled consumption to be extended to provide more comprehensive forms of premium heating and other services. The ability to influence demand patterns more finely so that they respond more immediately to changes in supply cost, is to the advantage of both suppliers and customers. It gives customers another form of choice.

Other applications already in place, or currently possible, include regional flood warning alarm systems, common remote control at multiple sites, such as weather-related environmental control in unmanned buildings, the control of services such as water and gas at point of entry into premises or, in the case of water, at points of connection to storage tanks and the replacement of other more expensive in-house remote control systems.

If a simple, readily-available, economic, one-way data communication channel is a requirement then Radio Teleswitching can meet it in a very short time.

‘Simple Teleswitch’

• Teleswitch replaces clock in Economy 7 systems
• Two modes:
  • Peak rate power (storage heaters off)
  • Off-peak power (storage heaters on)
• Cannot vary heating load time without varying peak/off-peak times

‘Double’ Teleswitch

• Twin teleswitch and meters
• Heating load is independent of tariff changes
• Able to offer:
  • X hours of heating per day
  • Fixed peak/off-peak times

What effect does radio teleswitching have on demand?

• Rapid changes in demand have to be met with flexible plant
• Can lead to high imbalance charges
• Smoother load curves
  • reduce need to call flexible plant
  • reward variable demand

Potential teleswitch services

• ‘Flattening’ the load curve
  • Short-term dispatch
  • Long-term agreed profiles
• Other services

If you have any issues or problems with the teleswitch installed in your home or business you should contact your electricity supplier. You can find out who your supplier is by contacting your electricity network operator.

Radio teleswitching is a very convenient and economic method of sending information and control signals to consumers’ premises and operational sites. Other benefits include:

• Plug-in-and-use simplicity – no need to purchase, install and maintain any dedicated hardware or software.
• Access to a powerful and reliable national broadcast communication system.
• Ability to operate the service from any chosen location within or outside the UK.
• Ability to switch 200MW or more of load with the transmission of a single message.
• Easy application of dynamic tariffs and load control (giving more precise and flexible control over energy consumption patterns, allowing supply businesses to optimise trading margins, and distribution businesses to accommodate operational constraints and defer capital expenditure.)
• Provides added value to customers (switching their loads for them and enabling them to benefit from competitive time of day supply tariff rates.)
• Easy addition of new customers and operational sites to the service (no wiring up to any network or payment of any connecting charges.)
• Compatible with competitive market requirements of 1998. (The system will allow the same level of access to any customers signed on anywhere in the UK – the communication costs have neither the distance dependency of telephone lines nor the physical interconnection constraints of power mains.)
• Freedom of adding more customers to the service with no increase in service charge (service charges are not related to the number of customers receiving the service).
• Other users to share the operational, maintenance and development costs of the system.
• Flexibility of changing the level of service required every year to match needs.
• A single organisation to take over all the responsibilities associated with the many functions required to provide the service.
• Ready access to assistance on operational issues and problems related to the system.
• Opportunities to influence developments of the system.
• Benefit of ideas from other users relating to the operation and development of the system.
• Reports on the performance of the service.

The system has continued to operate satisfactorily and has enabled user companies to provide added value to their customers.

The Central Teleswitch Control Unit (CTCU) was updated at the end of January 2008 to replace the obsolete hardware with brand new, modern, fully supported equipment. The old DEC MicroVAX machines were replaced with HP Integrity 2600s. The operating system was also upgraded to OpenVMS 8.3.

All communications lines have also been updated and internet access has been introduced in addition to the dial in access by modem.

The update has markedly improved the performance and stability of the system.

The life of Radio Teleswitching is being extended through to March 2024.