WO2021072457A2

WO2021072457A2 - Radio broadcast-controlled utilities management

Info

Publication number: WO2021072457A2
Application number: PCT/ZA2020/050057
Authority: WO
Inventors: Selvanathan Narainsamy; Andrew Gary Wright
Original assignee: Fmr Communication Technologies Canada, Inc.
Priority date: 2019-10-07
Filing date: 2020-10-07
Publication date: 2021-04-15
Also published as: WO2021072457A3

Abstract

A process and system to control the electrical loads constituted by electrical installations, domestic or industrial, which consume large amounts of electricity, but which can be switched off periodically, such as hot water cylinders. In exemplary implementations, the process and system include: a public broadcaster (24); a signal injector (30) interfaced with the broadcaster (24) by to inject control codes (preferably RDS signals) into the broadcast signal; a control centre (32) interfaced with the signal injector (30); load controllers (10), each connected to an electrical load (12), the load controllers (10) being configured to receive and respond to the broadcast control codes; and local control stations, each monitoring a plurality of load controllers (10).

Description

Radio Broadcast-Controlled Utilities Management

Field of the invention

[001] This invention relates to means and a method of managing the supply of utilities, particularly electricity.

Background to the invention

[002] The invention relates, in particular, †o demand-side management as a method of managing the supply of utilities. In demand-side utilities management the utility demand is balanced against the utility supply, such as the available supply of electricity, gas or wafer †o a reticulation network.

[003] The invention is described, in this specification, with reference †o a means and method of implementing demand-side load management in an electricity network. The means and method of the invention can also be applied †o the demand-side management of utilities other than electricity, for instance wafer and gas. If will be appreciated therefore, that whilst the invention is described with reference †o electrical load management, if is no† intended †o restrict the invention †o electricity as a utility.

[004] Electrical demand-side load management is the process of balancing the supply of electricity †o an electricity network with the electrical load on the network, by controlling the load rather than the electricity input (power station input). Demand-side utilities management is achieved by direct intervention by the utility supplier or service provider, in real time †o switch the utility supplied off or on a† the point of use, typically in the premises of the utilities consumer.

[005] Using the supply of electricity as an example, load management is achieved by direct intervention by the electricity supply utility in real time. Currently, the electricity utility must make use of timers or frequency sensitive relays (ripple control relays) that trigger circuit breakers on the network †o switch parts of the network (for instance, significant current-drawing appliances) on or off.

[006] Electrical demand-side management enables utilities †o reduce demand for electricity, which is particularly important during peak usage periods, since if can assist in reducing electricity production costs by reducing the need for peaking power plants.

[007] The domestic load (the load on the electricity supply imposed by households) contributes significantly †o peak load or demand, which has led electrical utilities, for many years, †o manage the domestic load par† of electricity networks. The domestic load has the added benefit of including relatively large (in a domestic context) current-drawing appliances which, taken individually do no† impose a significant load on the grid, bu† which, taken together, do in fact impose a significant load on the grid. Even more beneficially, these appliances can be interrupted periodically without causing any real inconvenience. These appliances include ho† water cylinders (ho† water geysers), under-floor space heating, air- conditioning systems, potable water pumps and swimming pool pumps, the operation of which can be interrupted periodically without causing real user inconvenience. Ho† water cylinders and water heaters for instance, can be interrupted for about an hour or two without inconveniencing the customer because of the thermal capacity of the water in the water heater.

[008] Ripple control systems †ha† make use of frequency sensitive relays (ripple control relays), appear †o be the most common form of load management used in many countries, including Australia, New Zealand, the United Kingdom, Germany, the Netherlands, and South Africa. In these systems, signal injectors (typically a plurality of interconnected signal injectors) are used †o inject or superimpose a higher-frequency signal onto the standard 50-60 Hz mains power signal. Ripple control relays are installed in participating premises, where the relays are wired in circuit with appliances that consume significant amounts of electricity, such as ho† water cylinders. When a ripple control relay detects the superimposed signal, the relay disengages its associated load from the mains, essentially shutting down the load (by switching off the ho† water cylinder, for instance) for a predetermined period of time, or until the superimposed signal is discontinued, or a different (switch on) signal is received.

[009] Ripple control systems currently in use often suffer from signal attenuation, which results in ineffectual switching and, hence, unpredictable load management. To exacerbate the problem, current ripple control systems can be bypassed a† the user level. For instance, consumers have learn† †ha† certain ripple receivers turn the load on after a reset. Simply switching off and restoring mains power after a short delay (typically around a minute) will reset the relay and restore the power even before the predetermined switch on time.

[0010] In addition †o these disadvantages, the communications infrastructure required appears †o a major factor inhibiting more widespread use of these technologies. Besides the communications equipment †ha† must be installed on each appliance †o be controlled, current technologies typically require the installation of a large number of signal transmitters (signal injectors) on the network †o be managed. This is because the signals generated by most currently available signal injectors are significantly attenuated by substations on the transmission network and, as a result, the signal injectors are typically located a† distribution level on the grid. As a result, a large number of signal injectors is required †o service a meaningful area of the grid. The operating voltages a† grid distribution level are nevertheless significant (typically 1 1 kV in South Africa) and signal injectors capable of interfacing with the grid a† this level are complex and therefore expensive, thereby greatly adding †o the cos† of using systems like this †o undertake demand- side electrical load management.

[0011] PCT paten† application no. PCT/ZA2010/00006 relates †o an inexpensive, easy †o install demand-side electrical load management system. Instead of the complex (and therefore expensive) electrical load management systems currently in use, as described above, PCT/ZA2010/00006 proposes the use of existing communication systems with wide coverage as a communication channel, such as a public radio frequency broadcasting network. The content of PCT paten† application no. PCT/ZA2010/00006 is incorporated herein by reference.

Summary of the invention

[0012] According †o this invention a process of controlling a controllable electrical load comprises: the preliminary steps of: connecting a load controller †o the load, the load controller including a switch, a radio frequency (RF) transceiver and programmable logic means, the switch being connected in circuit with the load; a† a public broadcaster that uses radio frequency (RF) broadcasting equipment †o broadcast, publicly, a RF broadcast signal, interfacing, with the broadcasting equipment, a signal injector configured †o inject a load control signal info the publicly broadcast RF signal and configuring the signal injector means and the broadcasting equipment †o transmit the load control signal as par† of the publicly broadcast RF signal; interfacing a control centre with the signal injector by configuring the control centre †o control the injection of the load control signal into the publicly broadcast RF signal; configuring the load controller transceiver †o receive the RF signal publicly broadcast by the broadcaster; interfacing a local control station with the control centre and the load controller by configuring the local control station and load controller for mutual asynchronous wireless communication and configuring the local control station and control centre for mutual asynchronous communication; programming the load controller programmable logic means †o monitor the load controller transceiver for reception of the publicly broadcast control signal; and programming the load controller programmable logic means to, on reception of the control signal, actuate the load controller switch and †o communicate the status of the load controller switch †o the local control station;

[0013] the process comprising the steps of: by means of the control centre, actuating the signal injector a† the broadcaster †o inject a load control signal info the publicly broadcast RF signal; by means of the broadcasting equipment, transmitting the injected load control signal as par† of the publicly broadcast RF signal; a† the load controller, by means of the load controller programmable logic means, monitoring the load controller transceiver for reception of the publicly broadcast control signal; a† the load controller, by means of the load controller programmable logic means, on reception of the control signal, actuating the load controller switch; a† the load controller, by means of the load controller programmable logic means, monitoring the switch actuation status of the load controller switch; and by means of the load controller transceiver, communicating the status of the load controller switch †o the local control station.

[0014] The invention includes a control system for a controllable electrical load, the system comprising: a load controller †ha† includes a switch, a radio frequency (RF) transceiver and programmable logic means, the switch being connected in circuit with the load; control signal injector means configured for interconnection with broadcasting equipment used by a broadcaster to broadcast a public radio frequency (RF) broadcasting service, the signal injector means being configured †o inject a load control signal info the publicly broadcast RF signal and the broadcasting equipment being configured †o transmit the load control signal as par† of the publicly broadcast RF signal; and a local control station; the load controller and local control station being configured for mutual, asynchronous RF communication; the load controller transceiver being configured †o receive the RF signal publicly broadcast by the broadcaster, including the control signal, and †o communicate wirelessly with the local control station; and the load controller programmable logic means being programmed:

†o monitor the load controller receiver for reception of a publicly broadcast control signal when, in use, a load control signal is transmitted as par† of the publicly broadcast RF signal; on reception of the control signal, †o actuate the load controller switch; after actuation of the load controller switch, †o monitor the switch actuation status of the load controller switch; and

†o communicate the status of the load controller switch †o the local control station.

[0015] The signal injection protocol will depend on the broadcast protocol for the publicly broadcast RF signal.

[0016] In the preferred form of the invention, the signal injector is configured †o inject the load control signal into the publicly broadcast RF signal as a Radio Data System (RDS) signal.

[0017] In countries where Digital Audio Broadcasting (DAB) has been implemented, the signal injector is configured †o inject the load control signal into the publicly broadcast RF signal as par† of the DAB signal, preferably by simply multiplexing load control signal the into the DAB signal ensemble.

[0018] As new broadcast technologies are adopted, the signal injection protocol must be adapted accordingly. For instance, Digital Multimedia Broadcasting (DMB) is a technology under development for the transmission of digital multimedia broadcasts, including TV, radio and da†acas†ing †o mobile devices such as mobile phones, laptops and GPS navigation systems. In such systems, the load control signal will be injected into the publicly broadcast RF signal in a manner appropriate †o the broadcast technology in use.

[0019] The electrical load may be constituted by any electrical installation †ha† consumes large amounts of electricity and, preferably by an electrical load which can be controlled without causing significant user inconvenience, typically by periodically switching the load off or on. Examples of such electrical loads include water heaters, such as ho† water cylinders, under-floor space heating, potable water pumps, swimming pool pumps, air conditioners and more.

[0020] Examples of high consumption electrical installations include area lighting and street lighting, which might no† be controllable †o the same extent (in †ha† lighting cannot be switched periodically without causing significant user inconvenience, bu† which can nevertheless be controlled in an appropriately designed electrical load demand management scheme.

[0021] The load controller switch is preferably constituted by a relay or circuit breaker switch, the load controller being configured for installation in or in conjunction with an electrical switchboard or adjacent †o or in conjunction with the controlled load. For instance, the load controller switch could be a circuit breaker connected in circuit with the mains electricity supply †o a ho† water heater.

[0022] In typical embodiments of the invention, the process and system include: a† leas† one public broadcaster; a† leas† one signal injector interfaced with the broadcasting equipment of the public broadcaster; at least one control centre interfaced with the signal injector; a plurality of load controllers, each connected in circuit †o an electrical load †o be managed; and a plurality of local control stations, each monitoring a plurality of load controllers, preferably arranged in separate groups, each of which is monitored by a local control station dedicated †o that group.

[0023] In instances in which the public broadcaster makes use of a signal distributor, the publicly broadcast signal will be the RF signal distributed by the signal distributor. In such instances, the public broadcaster and signal distributor, in combination, effectively constitute the public broadcaster for purposes of this invention, even though the signal injector will be interfaced with broadcasting equipment constituted by the signal distributor’s signal distribution equipment and the control centre will interface with the signal distributor. In this specification, therefore, the terms “broadcaster” and “broadcasting equipment” should, where appropriate, be interpreted †o include a signal distributor and signal distribution equipment, respectively.

[0024] The control centre is preferably located remotely of the premises of the broadcaster, the control centre being interfaced with the broadcaster by means of a communications interface, such as the Interne†.

[0025] A key aspect of this invention is the inclusion of a local control station or rather a plurality of local control stations, each of which monitors a discrete group of load controllers.

[0026] Each local control station is interfaced with the control centre for asynchronous communication by means of a communications interface, which need no† be a wireless or RF communications interface. The asynchronous communication interface could be either or both an Interne† and GSM communications backhaul. [0027] In addition, each local control station is configured for mutual asynchronous wireless communication with the load controllers in the group of controllers monitored by that local control station, preferably by way of the RF transceivers incorporated in the load controllers and a RF transceiver incorporated in each local control station.

[0028] The process and system are preferably configured †o include and enable the following communications: communication between the control centre and the signal injector — preferably but no† necessarily asynchronous, †o enable operator control of the signal injector (one-way communication) and signal injector status monitoring and reporting (two-way communication) — communication could be hard-wired, where the control centre and signal injector are implemented and installed in the same premises, or by means of remote communications, preferably Internet-based, for instance where the control centre and signal injector are implemented and installed in different premises; communication between the broadcaster (or signal distributor) and the load controllers in the process or system — this is a one-way, publicly broadcast RF transmission †ha† includes the load control signals — the signal distribution network could include rebroadcasting or repeater signal transmission stations; communication between the load controllers and the local control stations

— communication is by means of asynchronous, two-way RF transmissions enabled by means of transceivers incorporated in the load controllers and the local control stations, †o enable each load controller †o transmit load controller switch status data †o its dedicated local control station and †o enable each local control station †o communicate with and, if necessary control or override the load controllers in its dedicated group; and communication between the local control stations and the control centre

— which could be any appropriate form of communication, including by means of asynchronous, two-way RF transmissions enabled by means of transceivers incorporated in the control centre and the local control stations or either or both a GSM and Internet communications backhaul — to enable the local control stations to communicate load controller status data to the control centre and, in a developed form of the invention, †o enable the control centre †o communicate commands †o and from the local control stations †o control or override (if appropriate) the load controllers in the dedicated groups.

[0029] To facilitate the operation of the local control stations, the stations are preferably provided with programmable logic means programmed †o receive and initiate communications between the stations and load controllers monitored by the stations on the one hand and the stations and the control centre on the other hand, with communications, in each case, being triggered by predetermined trigger events.

[0030] The control centre includes programmable logic means.

[0031] In the preferred form of the invention, the control centre is implemented on a control centre server computer or computers.

[0032] The process and system may be configured †o incorporate an addressing system, with each load controller being allocated a unique address, †o enable management and switching of individual load controllers, if necessary.

[0033] The addressing system may conveniently be configured †o allocate the load controller addresses in accordance with a predetermined geospatial segmentation plan in terms of which the grid or network is segmented info regional and local segments, the addressing system enabling management and switching of load controllers in predetermined geospatial segments of the grid or network.

[0034] In this form of the invention, the addressing system is configured hierarchically, such that: the firs† (lowest) hierarchical level is constituted by individually addressable load controllers; the second hierarchical level is constituted by groups of load controllers corresponding †o the load controller groups monitored by the local control stations, each of which monitors a discrete group of load controllers; and the highest hierarchical level is constituted by the control centre.

[0035] A number of hierarchical levels could be interposed between the highest and lower hierarchical levels.

[0036] For instance, the addressing system hierarchy could include one or more of national, provincial, municipal, sub — municipal or any other geospafially determined hierarchical levels.

[0037] In addition, the control centre hierarchical level could also be segmented info a plurality of geospafially discrete, networked control centres.

[0038] The interface with the broadcast infrastructure could be included info the hierarchical addressing system †o incorporate the manner in which publicly broadcast signals are distributed.

[0039] In this embodiment of the invention, the addressing system makes use of the manner in which radio and television broadcasting are currently implemented. Typically, a signal distributor distributes the broadcasting signals of a plurality of broadcasters by broadcasting each broadcaster’s signal on a unique frequency. The broadcaster’s signal is typically distributed as an original signal on the broadcaster’s frequency. The original signal is disfribufed/broadcasf †o a number of regional and local re broad casting stations.

[0040] This signal distribution regime can be utilised †o good effect, †o localise the equipment forming par† of the system †o within broadly defined geospatial areas, by tuning the transceivers in the equipment †o the broadcast frequency of the local rebroadcasting stations serving particular geospatial areas. For instance, load controllers and local control stations can be configured (by radio frequency tuning) †o identify and respond only †o the local frequency of a particular broadcaster’s rebroadcas† signal as broadcast by the nearest local re broad casting station. [0041] In use, actuation of the load controller switch will switch the electrical load off or on.

[0042] To implement demand-side electrical load management in use, the process and system are configured †o broadcast a switch actuation code constituted by a swi†ch-off code and, after a predetermined time period (preferably several hours), †o broadcast a swi†ch-on code.

[0043] Using the load controller addressing system referred †o above, the switch actuation codes could be directed †o one or more groups of load controllers and, in particular, †o a group or groups of load controllers located in one or more pre defined geospatial locations.

[0044] To minimise high s†ar†-up loads, which might occur when a number of electrical loads are switched on simultaneously, the process and system are configured †o bring individual electrical loads back on-line in a manner that avoids high s†ar†-up loads.

[0045] In a preferred embodiment of this form of the invention, the load controller programmable logic means may be programmed †o select or generate (by means of a random number generator for instance), a random number between 1 and a predetermined high number (for example 900), the controller programmable logic means including a timer that is configured †o star† a time counter when, in use, the controller receives a swi†ch-on code, the time counter being configured †o count up, in predetermined increments of time, from 1 †o the predetermined high number and †o actuate the load controller switch †o switch the electrical load on when the time counter reaches the time increment corresponding †o the random number selected or generated by the controller programmable logic means.

[0046] In this embodiment of the invention, seconds of time may conveniently be used as time increments. For example, 900 seconds equates †o 15 minutes of time and, using 900 as the predetermined high number, in a given group of load controllers all of which simultaneously receive a swi†ch-on code, the load controllers will switch their respective electrical loads on randomly throughout a 15-minu†e period. [0047] In the example given immediately above, all the controlled electrical loads should be switched on at the end of a period of 15 minutes calculated from the time of fransmission/recepfion of the swi†ch-on code. However, there is no certainty that, in a given group of load controllers, all the controllers will in fact switch on in the 15- minute period. The controller might be faulty, for instance, or deliberately switched off or disconnected in an attempt †o defraud the system.

[0048] To solve this problem, the load controllers may conveniently be programmed, when the time counter reaches the selected high number and the load controller programmable logic means switches the load controller on, †o transmit a status report †o the local control station dedicated †o that group of load controllers, giving the on or off status of the load controller switch. In this way, the local control station should receive a full status report of all load controllers reporting †o that local control station by the end of the 15-minu†e period, which information if can then transmit †o the control centre.

[0049] The alternative is for all the load controllers in the group †o transmit their switch status †o the local control station a† the end of the 15-minu†e period.

[0050] Conversely, the controller programmable logic means could be programmed †o star† the time counter when, in use, the controller receives a swifch- off code, the time counter being configured †o count up, in time increments, from 1 †o the predetermined high number and †o transmit a status report †o the local control station dedicated †o that group of load controllers, giving the on or off status of the load controller switch.

[0051] This will give the local control station a full status report of whether or no† all the load controllers reporting †o †ha† local control station have in fact switched off when the time counter has finished counting up †o the predetermined high number (900 seconds/15 minutes in the example above).

[0052] The randomly timed status reports could also be initiated from the local control station, the programmable logic means of which could be programmed †o poll, randomly, the load controllers managed by †ha† local control station during a predetermined time after transmitting the switch item off code †o the load controllers.

[0053] Besides being programmed to manage these status reports, the local control station could also be programmed to transmit an override switch-off code †o any load controllers that have no† switched off when the time counter has finished counting up †o the predetermined high number (900 seconds/15 minutes in the example above).

[0054] In this embodiment of the invention, the load controller programmable logic means may be programmed, on reception of the override swi†ch-off code from the local control station, †o immediately transmit a report †o the local control station giving the on or off status of the load controller switch.

[0055] The load controller and local control station programmable logic means may be programmed †o repeat the override process a predetermined number of times and, if a† the end of the repeat process, the status of the load controller switch is reported as still being on, †o flag the affected load controller for intervention by personnel working on the instructions of the control centre.

[0056] In addition, the local control station programmable logic means may be programmed †o monitor a number of operating conditions of the local control station and the load controllers managed by the local control station, including load controllers no† responding †o communication, possible tampering and fraud and no signal conditions.

[0057] In addition †o monitoring these operating conditions, the load controllers 10 and possibly even the local control stations 38 may be fitted with a power consumption monitor and preferably also a bypass monitor

[0058] For such an implementation, the system programmable logic means will be programmed †o monitor electrical power consumption in the premises 14 or in a number of premises 14.

[0059] On-premises monitoring can be done using a power consumption meter incorporated into a load controller 10, thereby †o enable the load controller †o monitor the power consumption, over time, of the electrical load 12 †o which the load controller 10 is connected, which data can be stored in memory in the load controller programmable logic means. The stored power consumption data can then be transmitted †o the control centre computers 36. The power consumption data in issue could provide the utility with potentially valuable data and statistics in respect of client behaviour which would be useful in the utility’s load management programmes.

[0060] A dedicated bypass monitor or even the power consumption meter can be used †o monitor and flag potential bypass conditions for purposes of reporting †o the utility’s personnel using the reporting functions of the system of the invention. If will be appreciated that ripple control systems cannot perform a function such as this.

[0061] An implementation in which the local control stations 38 may be tiffed with power consumption monitors is described below with reference †o Figure 2 below.

[0062] As mentioned above, certain high consumption electrical installations, such as lighting and street lighting might no† be controllable †o the same extent as water heaters, for instance. However, by installing appropriate monitoring equipment, such as electrical power consumption monitoring equipment, in or on such installations, the local control station can be programmed †o monitor and use the monitoring equipment †o manage electrical installations like this.

[0063] For instance, by installing an electrical power consumption meter on a group of streetlights managed by a local control station, preferably a† the local control station, variations in power consumption could be used †o determine whether any of the streetlights are off when they should be on or on when they should be off.

Brief Description of the drawings

[0064] The invention will be further described with reference †o the accompanying drawings in which: Figure 1 is a block diagram illustrating a firs† embodiment of the invention; and

Figure 2 is a block diagram illustrating a second embodiment of the invention.

Description of embodiments of the invention

[0065] This invention provides a relatively inexpensive, easy to install system to control the electrical loads constituted by electrical appliances and installations, whether domestic, commercial or industrial, which consume large amounts of electricity, but which can be switched off periodically. Examples of such loads include appliances that can be switched off without causing any real inconvenience wafer heaters, such as ho† water cylinders (domestic or otherwise), under-floor space heating, water pumps, swimming pool pumps, air conditioners as well as appliances and loads †ha† do no† lend themselves readily †o being switched off without causing inconvenience, bu† †ha† can nevertheless be managed within a demand-side load management scheme.

[0066] In the examples illustrated in the drawings, Figure 1 illustrates the process and system of the invention with reference †o a ho† water cylinder controller and Figure 2 illustrates the process and system with reference to, street lighting. I† will be appreciated †ha† these exemplary implementations are provided purely for illustrative purposes and it is no† intended thereby †o restrict the invention †o these examples.

[0067] In Figures 1 and 2, certain elements of the process and system of the invention are duplicated. The duplicated elements are designated with identical numbers in both drawings.

[0068] As indicated above, in typical embodiments of the invention (as illustrated in Figures 1 and 2), the process and system of the invention include: a public broadcaster 24; a signal injector 30 interfaced with the broadcasting equipment of the broadcaster 24 by means of which control signals or control codes may be inserted or injected info the broadcast signal; a control centre 32 interfaced with the signal injector 30; a plurality of load controllers 10, 1 10, each connected in circuit †o an electrical load 12, 1 12 †o be managed, the load controllers 10, 1 10 being configured †o receive and respond †o the broadcast control codes; and a plurality of local control stations 38, each monitoring a plurality of load controllers 10, 1 10.

[0069] In practice, public broadcasters (radio stations) broadcast or distribute their public broadcasts by way of a signal distributor. A broadcast signal distributor is an entity that specialises in distributing (by way of broadcast radio frequency transmissions) the public broadcasts of, typically, a plurality of radio station broadcasters. The broadcasters (radio station owners) simply supply content or a signal for the signal distributor which then distributes the received content by means of broadcast radio frequency transmissions. The signal distributor owns and operates the radio frequency transmission equipment by means of which the radio station broadcasters’ content is transmitted or broadcast.

[0070] Unless clearly indicated by the context, therefore, the term “broadcaster”, when used in this specification, must be interpreted †o cover both a radio station owner and a signal distributor unless the context clearly indicates otherwise.

[0071] In effect, the radio station broadcaster and the signal distributor are essentially a combined broadcasting entity and, for convenience and ease of reference, the broadcaster and signal distributor are indicated, in the drawings, by means of functional block 24. The combined broadcasting entity will be referred †o in this specification as the “broadcaster 24” with the intention of thereby designating either or both the broadcaster and/or the signal distributor, as the context may indicate.

[0072] In Figure 1 , the electrical load control system of the invention is illustrated with reference †o a load controller 10 configured †o control a controllable electrical load 12 that, in this example is constituted by a ho† water cylinder 12.1 installed, for example, in domestic premises 14. A plurality of houses 14 illustrate the domestic premises in each of which a load controller 10 is installed in circuit with the electrical load/ho† water cylinder 12.1 typically installed in the premises 14.

[0073] The load controller 10 includes a load controller control uni† †ha† includes switching circuitry and programmable logic, preferably implemented on one or more integrated circuit chips. The load controller control uni† includes appropriate circuitry and wiring, including control circuitry.

[0074] The load controller switching circuitry is connected in circuit with the electrical load 12. The load controller 10 may be installed in close proximity †o the electrical load/ho† water cylinder 12, for example, bu† it is probably more convenient †o install the load controller 10 in the electrical distribution board 20 serving the premises 14, with the load controller switching circuitry connected for control of the circuit breaker serving the electrical load (in this example, ho† water cylinder 12.1).

[0075] Certain of the premises 14 may have additional loads connected †o the distribution board 20, such as under-floor space heating, air-conditioning systems, potable water pumps and swimming pool pumps, the operation of which can be interrupted periodically without causing real user inconvenience. The additional loads are numbered 12.2 ... 12.n , each of which may conveniently be controlled by a separate and additional load controller 10.2 ... 10.

[0076] The load controller 10 includes a radio frequency (RF) transceiver 16 (16.2 ... 16.n) preset †o receive a predetermined radio frequency (RF) signal 22 of a publicly broadcast radio frequency (RF) broadcasting service - the RF transceiver 16 is tuned †o the predetermined frequency. This is the frequency on which the broadcaster broadcasts the control codes for reception by the RF transceiver and a programmed response by the load controller 10.

[0077] In South Africa, Sentech is the principal common carrier broadcasting signal distributor. Sentech operates a number of broadcasting transmitter stations located throughout South Africa from which short-wave, medium wave, FM, television and MMDS transmitters are used †o transmit the broadcast signals of a plurality of radio station broadcasters. As illustrated in both drawings, a signal distributor such as Senfech will normally make use of a network of transmitter stations including a central transmitter station, which typically includes a broadcasting tower 26, that broadcasts the broadcast signals of a plurality of radio station broadcasters, each broadcast on a radio-frequency dedicated †o a specific radio station broadcaster.

[0078] To ensure qualify of transmission in FM radio broadcasting in particular, the signal distributor’s distribution network includes a widely distributed network of regional signal redistribution or rebroadcasfing stations 28. Besides rebroadcasfing centrally originated original signals 22.1 , the regional rebroadcasfing stations 28 are typically also set up †o serve regional radio station broadcasters, each of which broadcasts only †o a specific geographic region. Such regional rebroadcasfing stations 28 will include broadcasting equipment that broadcasts the regional radio station signal on a regional radio frequency dedicated †o that regional radio station broadcaster. The network could include local- and even lower-ranking rebroadcasfing stations in the network hierarchy which, for the sake of simplicity, are no† illustrated or described herein.

[0079] Such a broadcasting network (in simplified form) is illustrated diagrammatically in the drawings in which the broadcaster 24 broadcasts a centrally originating original signal 22.1 from the central tower 26. The regional rebroadcasfing stations 28 redistribute (re-broadcas†) the original signal 22.1 within geographically disparate regions, as regional signals 22.2. The rebroadcasfing stations 28 make use of lower power transmissions compared †o †ha† of the central transmitter tower 26, as a result of which each re-broadcas† regional signal 22.2 is transmitted †o a dedicated and relatively small geographical area (or dedicated regional broadcast footprint) compared †o the larger geographical area served by the entire signal distribution network. Each rebroadcasfing station 28 transmits its original signal 22.2 on a frequency †ha† differs slightly from the transmission frequency of the original signal 22.1 — the frequency of the regional signal 22.2 is spaced apart from bu† closely adjacent †o the transmission frequency of the original signal 22.1 .

[0080] In combination, the regional broadcast footprint of each rebroadcasfing station 28 serves †o localise the regional broadcast signal 22.2 geographically, where if is identified by its unique transmission frequency.

[0081] To this end, instead of being tuned †o the original signal 22.1 of the broadcasting service, the load controller transceiver 16 is tuned, instead, †o the regional signal 22.2 of the closes† rebroadcasting station 28, thereby automatically localising the load controller 10 within the regional broadcast footprint of †ha† rebroadcasting station 28. As a result, the load controller 10 is regionally addressable simply by broadcasting a signal on the frequency of the regional signal 22.2 of †ha† rebroadcasting station 28. The load controller programmable logic means is preferably programmed †o scroll the transceiver 16 through the available radio frequency spectrum, †o monitor for the strongest RF signal received and †o latch or log onto †ha† signal for subsequent operations. In practice, the strongest signal will be the signal transmitted by the closes† re broad casting station 28. This can be done through self-programming, hard wiring or a combination of the two.

[0082] In FM radio broadcasting, the currently most ubiquitous means of inserting control signals into the broadcast transmission is by the injection of Radio Data System (RDS) signals into the publicly broadcast FM radio transmission.

[0083] The Radio Data System (RDS) or Radio Broadcast Data System (RBDS) as it is known in the United States of America (published as IEC (International Electrotechnical Commission) standard 62106), is a communications protocol for embedding digital data signals in FM radio broadcasts. The RDS protocol is well established (it is currently more than 30 years old), widely used worldwide and makes use of low-priced componentry — it is typically implemented on an inexpensive integrated circuit chip †ha† is simple and inexpensive †o integrate into equipment such as smartphones and FM radio receivers. The IEC approved and published an updated RDS standard (version IEC 62106:2018) in October 2018, now generally referred †o as RDS2, †ha† greatly expands the Open Data Application (ODA) capacity of the earlier RDS standard, which means †ha† a large number of data file types, with significantly increased data capacity can now be accommodated for injection into the FM radio transmission.

[0084] In the currently preferred form of the invention, therefore, the signal injector is configured to inject the load control signal into the publicly broadcast RF signal as a Radio Data System (RDS) signal.

[0085] RDS is a standard that is compatible with traditional radio broadcasting, in which radio station broadcasters broadcast radio programmes on different frequencies, so that the radio receiver must be tuned to the relevant frequency to receive the broadcast. With the advent of digital technologies, it has become evident that the system of broadcasting is spectrum-inefficient since it uses up a comparatively large amount of spectrum for a relatively small number of stations. This has given rise to the development of digital broadcasting systems including Digital Audio Broadcasting (DAB) and Digital Multimedia Broadcasting (DMB), both consisting of digital radio broadcasting systems that, through the application of multiplexing and compression, combine multiple audio and/or video streams onto a relatively narrow band centred on a single broadcast frequency. DAB and DMB are capable of carrying digital data additional to the audio/video/multimedia data or codecs to transmit and carry real-time information such as song titles, news or traffic updates, for instance. These digital technologies are currently in use or on trial in a number of countries, notably in Europe and Australasia.

[0086] Load control signal injection, referring in particular to the FM RDS environment, is undertaken by means of a RDS signal encoder that, in most cases, is integrated with the audio processor interfaced with the broadcasting equipment of the signal distributor. The audio processor is typically constituted by a digital multiplexer located at the central transmitter station of the signal distributor, where it is interfaced with the signal distributor’s broadcasting equipment for transmission of the RDS signal as part of the original FM radio signal transmitted by the signal distributor. The signal distributor’s regional rebroadcasting stations are configured to receive and transmit the RDS signal, unchanged, as part of the regional FM radio signal re-broadcast by the regional rebroadcasting station 28.

[0087] Referring to the drawings, the RDS signal must first be formulated as a load controller control signal which the load controllers 10 in the system are programmed to receive and interpret.

[0088] Signal formulation is undertaken at a control centre 32 which could be located at (32.1 ) or remotely (32.2) of the broadcaster 24. In each case, the control centre 32 is interfaced 34 with the digital multiplexing equipment 30. The interface 34 could be direct (34.1 ), in situations where the control centre 32.1 is located a† the broadcaster 24. Alternatively, the interface 34 could be indirect, byway of a remote communications backhaul 34.2, which could comprise any one or more of a radio frequency link, a telecommunications link or an IP (Interne† protocol) communications link. The remote communications backhaul 34.2 is appropriate in situations where the control centre 32.2 is located remotely of the broadcaster 24.

[0089] The control centre 32 requires little more than a personal computer 36 to manage the signal formulation process, bu† in certain implementations, the control centre computer 36.1 could be replaced by a remotely hosted computer server or networked computers/servers (36.2). The control centre computer 36 is interfaced with the digital multiplexer 30 by means of the control centre communications interface 34.

[0090] The FM radio signals broadcast by the signal distributor are broadcast widely and, as a result, are received directly by the load controller transceivers 16. The control codes distributed by the broadcast are likewise received directly by the load controller transceivers.

[0091] The local control stations 38 constitute a key aspect of this invention.

[0092] In practice, a large number of load controllers 10 will be installed in a multiplicity of premises 14 †ha† are grouped within the regional broadcast footprint of each of a number of regional rebroadcasting stations 28. The load controllers 10 are controlled by means of control signals transmitted on the broadcasting network. The load controllers 10 are arranged in load controller groups 40, each managed by a dedicated local control station 38. This is done for a management purposes, †o enable administration and management of electrical loads 12 a† the premises 14, in blocks or groups 40.

[0093] The local control stations 38 are provided with programmable logic means programmed †o receive and initiate communications between the local control stations 38 and the load controllers 10 monitored by each of the stations on the one hand and between the local control stations 38 and the control centre 32 on the other hand.

[0094] The local control stations 38 monitor the load controllers 10 in accordance with a monitoring protocol programmed into programmable logic in the load controllers 10 and local control stations 38, respectively and by means of a communications interface 42 comprising asynchronous, two-way RF transmissions enabled by means of transceivers incorporated in the load controllers 10 and the local control stations 38. In accordance with the load controller monitoring protocol, load controller switch status data is communicated †o the dedicated local control station 38 of each load controller 10, which is also programmed †o receive and respond †o control commands communicated †o the local control stations 38 dedicated †o that load controller 10.

[0095] The local control stations 38 are interfaced with the central control centre for asynchronous communication by means of a communications interface 44, which could be a wireless or RF communications interface, but which, preferably, is constituted by either or both an Interne† and GSM communications backhaul. In addition, each local control station 38 is configured for mutual asynchronous wireless communication with the load controllers 10 in the group of controllers 10 monitored by †ha† local control station 38 by way of the RF transceivers 16 incorporated in the load controllers 10 and a RF transceiver incorporated in each local control station.

[0096] The process and system are configured †o include and enable the following communications:

[0097] communication between the central control centre 32 and the signal injector 30 — preferably bu† no† necessarily asynchronous, †o enable operator control of the signal injector by way of one-way communication and signal injector status monitoring and reporting by way of two-way communication) — as indicated above, the communications interface is hard-wired (34.1 ), where the central control centre 32.1 and signal injector 30 are implemented and installed in the same premises (such as the premises of the broadcaster 24) or achieved by means of a communications interface (34.2) using GSM/ln†erne†-based remote communications where the central control centre 32.2 is implemented in a location remote from the location of the signal injector 30;

[0098] communication between the broadcaster 24 and the load controllers 10 in the process or system — this is a one-way, publicly broadcast RF transmission 22 that includes the load control signals undertaken by means of a signal distribution network including a central broadcasting tower 26 and satellite or repeater signal transmission stations, such as the rebroadcasfing stations 28;

[0099] communication between the load controllers 10 and the local control stations 38 — communication is by means of asynchronous, two-way RF transmissions enabled by means of transceivers incorporated in the load controllers 10 and the local control stations 38, to enable each load controller 10 to transmit load controller switch status data †o its dedicated local control station 38 and †o enable each local control station 38 to communicate with and, if necessary control or override the load controllers 10 in its dedicated group; and

[00100] communication between the local control stations 38 and the central control centre 32, preferably by means of asynchronous, two-way GSM and Interne† communications 44 — †o enable the local control stations 38 to communicate load controller status data †o the central control centre 32 and, in a developed form of the invention, †o enable the central control centre 32 †o communicate commands †o and from the local control stations 38 to control or override (if appropriate) the load controllers 10 in the respective load controller groups 40 managed by each of the local control stations 38.

[00101] Communications between the local control stations 38, the load controllers 10 and the control centre 32 are initiated by pre-programmed trigger events constituted, in some cases, by control codes broadcast across the system and, in some cases, by pre-programmed trigger events.

[00102] The control codes broadcast by the broadcaster 24 are formulated, a† the control centre 32, in accordance with a load controller addressing system — a coding system †ha† addresses load controllers in a predetermined manner.

[00103] A† its most basic level, the coding system is designed to work in conjunction with the geospafially addressable nature of the hierarchical FM radio signal distribution system and, in particular, the geographically localised regional broadcast signals 22.2 of the FM radio distribution network. As described above, each load controller transceiver 16 is tuned †o the regional signal 22.2 of the rebroadcasfing station 28 closes† †o the load controller 10 (the rebroadcasting station 28 exhibiting the strongest signal), thereby automatically localising the load controller 10 within the regional broadcast footprint of †ha† rebroadcasting station 28. As a result, the load controller 10 is regionally addressable simply by broadcasting a signal on the frequency of the regional signal 22.2 of †ha† rebroadcasting station 28.

[00104] In practice this will be done with the aid of the RDS Programme Identification (PI) service. This is a service provided by radio stations transmitting RDS data as part of the FM radio broadcast. I† is 4-digi† hexadecimal number †ha† allows radios †o identify radio stations by their PI code. Using the PI service, the load controllers 10 intended for a particular region could be pre-programmed with the PI codes of the regional radio station or stations of the radio station local †o †ha† region, thereby †o permit regional addressing of those load controllers by simply broadcasting the control signals on the broadcasts of the radio station answering †o a particular PI code. A

[00105] Whilst it might be feasible †o address load controllers 10 individually, the sheer number of load controllers 10 that would need †o be addressed and managed and the radio bandwidth required †o manage the resultant communications traffic militate against such an approach. Instead, the load controllers 10 are divided and addressed in more granular groupings, the load controllers 10 being coded, in programmable logic, with individual, local and regional address codes, thereby providing the capability †o address load controllers individually, on a local or group (40) level, on a regional level (corresponding †o the regional broadcast footprint of the relevant rebroadcasting station 28) and, if necessary, on a more global (for instance national) level. I† is of course possible †o introduce more or less levels into such a hierarchical load controller addressing system.

[00106] A† its lowest hierarchical level, therefore, the load controller addressing system relies on system of discrete, individual load controller address codes — individual addressability might be cumbersome on a global level, but on a more local level might be useful. For example, individual addressability will enable local communications as between a local control station 38 and a load controller 10 located within the group 40 of load controllers 10 managed by that local control station 38.

[00107] In use, actuation of the load controller 10 will switch the electrical load 12 off or on.

[00108] To implement demand-side electrical load management in use, the utility or electricity supplier is given management control of the control centre 32 by means of which the entire load management system can be managed. The utility will have devised a demand-side electrical load management scheme in terms of which predetermined sections of the electrical grid will be switched off for predetermined periods of time and then switched on again. With such a demand- side electrical load management scheme in mind, the utility will operate the control centre 32 †o inject load controller switch actuation codes info the broadcast signals 22 of the broadcaster 24 by means of the signal injector 30.

[00109] Typically, the firs† switch actuation code †o be broadcast will be constituted by a swi†ch-off code and, after a predetermined time period (preferably several hours), a swi†ch-on code will be broadcast. These switch actuation codes will be broadcast within the regional broadcast footprints of predetermined regions, where the switch actuation codes will affect the load controllers 10 across the entire region or only within predetermined discreetly addressable local groups 40 within the region, as determined by the utility’s management scheme.

[00110] It will be seen †ha† the implementation of the scheme, in its entirety, lies within the control of the utility. The broadcaster 24 simply provides a carrier for the broadcast of the switching codes.

[00111] Using the load controller addressing system referred †o above, the switch actuation codes could be directed †o one or more groups 40 of load controllers 10 and, in particular, †o a group or groups 40 of load controllers 10 located in one or more pre-defined geospatial locations.

[00112] To minimise high start-up loads, which might occur when a number of electrical loads are switched on simultaneously, the process and system are configured bring individual electrical loads back on-line in a manner that avoids high s†ar†-up loads.

[00113] This is done by introducing a random timed switching delay info the system.

[00114] During the installation of the load controllers 10 a† the premises 14, each load controller 10 is initialised and registered on the system using the communications protocols described above. The load controller programmable logic means is programmed, in the process of initialisation, †o select (from a register of numbers) or †o generate (by means of a random number generator for instance), a random number between 1 and a predetermined high number (for example 900). The controller programmable logic means includes a timer that is configured †o star† a time counter when, in use, the controller 10 receives a broadcast swi†ch-on code, the time counter being configured †o count up, in predetermined increments of time (typically in seconds of time) from 1 †o the predetermined high number and †o actuate the load controller switch †o switch the electrical load 12 on when the time counter reaches the time increment corresponding †o the random number selected or generated by the controller programmable logic means. The time period between the time of reception of the swi†ch-on code and the time when the time counter reaches the random number is the timed switching delay.

[00115] Where seconds of time are used as time increments, the predetermined high number could be a predetermined number of seconds, say 900 seconds (which equates †o 15 minutes of time).

[00116] In use and using 900 as the predetermined high number, in a given group of load controllers all 10 of which simultaneously receive a swi†ch-on code, the load controllers 10 will switch their respective electrical loads 12 on randomly throughout the 15-minu†e timed switching delay.

[00117] In the example given immediately above, the electrical grid is protected from high s†ar†-up loads.

[00118] In addition, the implementation of an extended timed switching delay provides a useful system management opportunity. In this regard, all the controlled electrical loads should be switched on at the end of the timed switching delay (15 minutes calculated from the time of transmission/reception of the switch-on code). However, there is no certainty that, in a given group of load controllers, all the controllers will in fact switch on in the 15-minute timed switching delay period. One or more controllers 10 might be faulty, for instance, or deliberately switched off or disconnected in an attempt to defraud the system.

[00119] To manage this issue, the load controllers 10 are programmed, when, in each load controller 10, the time counter reaches the randomly selected high number and the load controller programmable logic means switches the load controller 10 on, to transmit a status report to the local control station 38 dedicated to that group of load controllers 10, giving the on or off status of the load controller switch. In this way, the local control station 38 should receive a full status report of all load controllers 10 reporting to that local control station 38 by the end of the 15- minute period, which information it can then transmit to the control centre 32.

[00120] The alternative is for all the load controllers 10 in the group 40 to transmit their switch status to the local control station 38 at the end of the 15-minute period.

[00121] This facility can also be used the other way round.

[00122] For example, the controller programmable logic means could be programmed to start the time counter when, in use, the controller 10 receives a switch-off code, the time counter being configured to count up, in time increments, from 1 to 900 and, either at the end of the 900-2nd period or at the end of the timed switching delay period determined in respect of that load controller 10, to transmit a status report to the local control station 38 dedicated to that group of load controllers 10, giving the on or off status of the load controller switch of each load controller 10. Either way, at the end of the 15-minute timed switching delay period, the local control station 38 will have a full status report in respect of all the load controllers 10 reporting to that local control station 38 and whether or not the load controllers 10 have in fact all switched off in response †o the broadcast swifch-off code.

[00123] Besides s†ar†-up load management, the use of randomly timing the transmission of the status reports from the various load controllers serves †o manage transmission traffic in the RF link between the load controllers and the local control station.

[00124] In addition †o being programmed †o manage these status reports, the local control station 38 is also programmed †o transmit an override swifch-off code †o any load controllers 10 that have no† switched off when the time counter has finished counting up the predetermined timed switching delay. The load controller programmable logic means is programmed, on reception of the override swi†ch-off code from the local control station 38, to immediately transmit a report †o the local control station 38 giving the on or off status of the load controller switch. The load controller 10 and local control station 38 programmable logic means are programmed †o repeat the override process a predetermined number of times and, if a† the end of the repeat process, the status of the load controller switch is reported as still being on, the system will flag the affected load controller for intervention by personnel working on the instructions of the control centre 32.

[00125] The local control station 38 programmable logic means is also programmed †o monitor a number of operating conditions of the local control station 38 and the load controllers 10 managed by the local control station 38, including monitoring for any load controller 10 no† responding †o communication, possible tampering indicators, possible fraud indicators and no-signal conditions.

[00126] Figure 2 illustrates the application of the system and process of the invention †o the demand-side load management of high consumption electrical installations, such as lighting and street lighting †ha† are no† as readily controllable as the water heaters of Figure 1. Using the system and process of the invention together with appropriate monitoring equipment, such as electrical power consumption monitoring equipment, it is nevertheless possible †o implement demand-side load management in or on such electrical loads. As mentioned above, a number of the process and system elements of Figure 2 are identical †o those of Figure 1 and, hence, are identically numbered. The remaining system elements of Figure 2 are similar †o those of Figure 1 and are designated with like numbering — similar elements are given similar numbers in the 100s.

[00127] Figure 2 illustrates a process and system including a broadcaster 24 that broadcasts a RF/FM signal 22 as an original signal 22.1 from a broadcasting tower 26, which is relayed by a rebroadcasfing station 28 as a regional signal 22.2. A digital multiplexer 30 is used †o inject a pre-formula†ed control signal info the broadcast signal 22 as a RDS signal, the control signal being formulated on a computer 36 operated a† a control centre 32 that might be local (32.1 ) or remote from (32.2) relative †o the broadcaster 24, the control centre 32 communicating with the multiplexer 30 by way of a control centre communications interface 34.

[00128] Essentially identical local control stations 38 are interposed between the broadcaster 24, 28 and the managed electrical loads which, in this example, are constituted by groups of streetlights or area lighting — Figure 2 illustrates a single group of streetlights 1 12 managed by a single load controller 1 10, as an example.

[00129] The local control station 38 is programmed †o monitor and use pre-insfalled monitoring equipment †o manage the street lighting electrical load 1 12. The load controller 1 10 incorporates an electrical power consumption meter which monitors and flags variations in power consumption by the electrical load 1 12. Such variations could include power variations arising from lights that are off when they should be on or lights that are on when they should be off. In addition, tampering and fraud conditions could be monitored and flagged.

[00130] Communication between the load controller 1 10 and the electrical load is direct, using the monitoring equipment installed in the load controller 1 10. The remaining communications in the system illustrated follow a communications protocol similar †o that illustrated with reference †o Figure 1 and allow the control centre †o control and manage the switching (off and on) of the street lighting electrical load and †o monitor the operating conditions of the electrical load is determined by the monitoring equipment installed in the load controller 1 10.

Claims

1 . A process of controlling a controllable electrical load comprising: the preliminary steps of: connecting a load controller †o the load, the load controller including a switch, a radio frequency (RF) transceiver and programmable logic means, the switch being connected in circuit with the load; a† a public broadcaster that uses radio frequency (RF) broadcasting equipment †o broadcast, publicly, a RF broadcast signal, interfacing, with the broadcasting equipment, a signal injector configured †o inject a load control signal info the publicly broadcast RF signal and configuring the signal injector means and the broadcasting equipment †o transmit the load control signal as par† of the publicly broadcast RF signal; interfacing a control centre with the signal injector by configuring the control centre †o control the injection of the load control signal into the publicly broadcast RF signal; configuring the load controller transceiver †o receive the RF signal publicly broadcast by the broadcaster; interfacing a local control station with the control centre and the load controller by configuring the local control station and load controller for mutual asynchronous wireless communication and configuring the local control station and control centre for mutual asynchronous communication; programming the load controller programmable logic means †o monitor the load controller transceiver for reception of the publicly broadcast control signal; and programming the load controller programmable logic means to, on reception of the control signal, actuate the load controller switch and †o communicate the status of the load controller switch †o the local control station; the process comprising the steps of: by means of the control centre, actuating the signal injector a† the broadcaster †o inject a load control signal info the publicly broadcast RF signal; by means of the broadcasting equipment, transmitting the injected load control signal as par† of the publicly broadcast RF signal; a† the load controller, by means of the load controller programmable logic means, monitoring the load controller transceiver for reception of the publicly broadcast control signal; a† the load controller, by means of the load controller programmable logic means, on reception of the control signal, actuating the load controller switch; a† the load controller, by means of the load controller programmable logic means, monitoring the switch actuation status of the load controller switch; and by means of the load controller transceiver, communicating the status of the load controller switch †o the local control station.

2. A control system for a controllable electrical load, the system comprising: a load controller that includes a switch, a radio frequency (RF) transceiver and programmable logic means, the switch being connected in circuit with the load; control signal injector means configured for interconnection with broadcasting equipment used by a broadcaster †o broadcast a public radio frequency (RF) broadcasting service, the signal injector means being configured †o inject a load control signal into the publicly broadcast RF signal and the broadcasting equipment being configured †o transmit the load control signal as par† of the publicly broadcast RF signal; and a local control station; the load controller and local control station being configured for mutual, asynchronous RF communication; the load controller transceiver being configured †o receive the RF signal publicly broadcast by the broadcaster, including the control signal, and †o communicate wirelessly with the local control station; and the load controller programmable logic means being programmed:

3. The control system of claim 2, including: a† leas† one public broadcaster; a† leas† one signal injector interfaced with the broadcasting equipment of the public broadcaster; a† leas† one control centre interfaced with the signal injector; a plurality of load controllers, each connected in circuit †o an electrical load †o be managed; and a plurality of local control stations, each monitoring a plurality of load controllers, preferably arranged in separate groups, each of which is monitored by a local control station dedicated †o that group.

4. The control system of claim 3 in which each of the local control stations monitors a discrete group of load controllers.

5. The control system of claim 4 in which each local control station is interfaced with the control centre for asynchronous communication by means of a communications interface.

6. The control system of claim 5 in which each local control station is configured for mutual asynchronous wireless communication with the load controllers in the group of controllers monitored by that local control station by way of the RF transceivers incorporated in the load controllers and a RF transceiver incorporated in each local control station.

7. The control system of claim 6, incorporating incorporates an addressing system in which each load controller is allocated a unique address, †o enable management and switching of individual load controllers.

8. The control system of claim 7 in which the addressing system is configured †o allocate the load controller addresses in accordance with a predetermined geospatial segmentation plan in terms of which the grid or network is segmented info regional and local segments, the addressing system being configured †o enable management and switching of load controllers in predetermined geospatial segments of the grid or network.

9. The control system of claim 8 in which the addressing system is configured hierarchically, such that: the firs† (lowest) hierarchical level is constituted by individually addressable load controllers; the second hierarchical level is constituted by groups of load controllers corresponding †o the load controller groups monitored by the local control stations, each of which monitors a discrete group of load controllers; and the highest hierarchical level is constituted by the control centre.

10. The control system of claim 9 in which a number of hierarchical levels are interposed between the highest and lower hierarchical levels.

1 1. The control system of claim 10 in which the addressing system hierarchy includes one or more of national, provincial, municipal, sub — municipal or any other geospafially determined hierarchical levels.

12. The control system of claim 12 in which the control centre hierarchical level is segmented info a plurality of geospafially discrete, networked control centres.

13. The control system of any one of claims 2 †o 12 which is configured †o broadcast a switch actuation code constituted by a swi†ch-off code and, after a predetermined time period, †o broadcast an actuation code constituted by a swi†ch-on code.

14. The control system of claim 13 including an addressing system according †o any one of claims 8 to 12 which is configured †o direct the switch actuation codes †o load controllers load controllers located in one or more pre-defined geospatial locations.

15. The control system of claim 14 in which the load controller programmable logic means is programmed †o generate a random number between 1 and a predetermined high number, the controller programmable logic means including a timer that is configured †o star† a time counter when, in use, the controller receives a swi†ch-on code, the time counter being configured †o count up, in predetermined increments of time, from 1 †o the predetermined high number and †o actuate the load controller switch †o switch the electrical load on when the time counter reaches the time increment corresponding †o the random number.

16. The control system of claim 15 in which the load controller programmable logic means is programmed, when the time counter reaches the selected high number and the load controller programmable logic means switches the load controller on, †o transmit a status report †o the local control station dedicated †o the group of load controllers within which the load controller is located, giving the on or off status of the load controller switch.

17. The control system of claim 16 in which the load controller programmable logic means is programmed †o star† the time counter when, in use, the controller receives a swi†ch-off code, the time counter being configured †o count up, in time increments, from 1 †o the predetermined high number and †o transmit a status report †o the local control station dedicated †o †ha† group of load controllers, giving the on or off status of the load controller switch.

18. The control system of claim 17 in which the local control station programmable logic means is programmed †o transmit an override swi†ch-off code †o any load controller control by that local control station that has no† switched off when the time counter has finished counting up †o the predetermined high number.

19. The control system of claim 18 in which the load controller and local control station programmable logic means are programmed †o repeat the override process a predetermined number of times and, if a† the end of the repeat process, the status of the load controller switch is reported as still being on, †o flag the affected load controller for on-si†e attendance by the control system operator.

20. The control system of claims 2 †o 19 in which the local control station programmable logic means is programmed †o monitor predetermined operating conditions of the local control station and the load controllers managed by the local control station, including the electrical power consumption of each of the appliances connected †o the load controllers, load controllers no† responding †o communication, possible tampering and fraud and no-signal conditions.

21 . The control system of claim 20 for use in conjunction with a high consumption electrical installation comprising a plurality of electrical loads all switched by a single load controller, in which the local control station programmable logic means is programmed †o monitor a† leas† the combined electrical power consumption of the plurality of electrical loads and †o report any abnormal variation in power consumption.

22. The control system of any one of claims 2 †o 21 configured for interfacing with a broadcast infrastructure in which: a signal distributor distributes the broadcasting signals of a plurality of broadcasters by broadcasting each broadcaster’s signal as an original signal on a frequency unique †o †ha† broadcaster; the signal distributor broadcasts the original signals †o a number of rebroadcasting stations geographically remote from one another and the signal distributor; the rebroadcasting stations rebroadcas† the received original signal as a rebroadcas† signal on a frequency different †o the original signal; the control system being configured for interfacing with such a broadcast infrastructure in †ha† the transceivers of either or both the load controllers and local control stations in the control system are configured (by radio frequency tuning) †o identify and respond only †o the frequency of the rebroadcas† signal broadcast by the nearest rebroadcasting station.

23. The control system of any one of claims 2 †o 22 in which the signal injector is configured †o inject the load control signal into the publicly broadcast RF signal as a Radio Data System (RDS) signal.

24. The control system of any one of claims 2 †o 22 in which the signal injector is configured †o inject the load control signal into the publicly broadcast RF signal as par† of a Digital Audio Broadcasting (DAB) signal.