Method of and apparatus for controlling loads on an electrical power supply

Claim 3

A method as claimed in claim 1 wherein each of said control signals comprises one or a sequence of similar waveform modifications of the alternating waveform which are distinguishable by the number of waveform modifications in the sequence and wherein, at each individual load to be controlled, the signals are selected in response to counting of the number of waveform modifications received.

Claim 4

A method as claimed in claim 2 wherein at each individual load the supply is controlled by switching the supply off for a predetermined time period when the number of waveform modifications counted at that load reaches a predetermined number.

Claim 5

A method as claimed in claim 1 wherein at each individual load the supply is controlled by switching the supply off for a predetermined time period when the selected signal is received.

Claim 6

A method as claimed in claim 3 wherein the counting is reset during or at the end of said predetermined time period.

Claim 9

A method as claimed in claim 6 wherein the counter is decremented only when the overall demand is below said predetermined limited by a predetermined magnitude.

Claim 10

A method as claimed in claim 6 wherein said signal is representative of the demand and wherein, at an individual load, decrementing of the counter is effected when the demand is less than said predetermined limit by a predetermined amount.

Claim 11

A method as claimed in claim 6 wherein the duration of the open-circuit switching is substantially less than a cycle of the alternating electric power supply, the duration being a measure of the magnitude of the demand.

Claim 12

A method as claimed in claim 9 wherein the open-circuit switching is effected by switching off the power supply, using a solid state switch, immediately before the zero crossing of the voltage waveform or current waveform and switching the power supply on again on a short time later, the duration of the interruption being small compared with the time duration of a cycle of the waveform.

Claim 13

Apparatus for controlling loads within the premises of consumers on an alternating electrical power supply comprising, at each individual load to be controlled, means for detecting one out of a plurality of different signals broadcast over the power supply network within the premises of the associated consumer as distinguishable modifications of the power supply waveform, and switching means responsive to the detected signal for interrupting the power supply to the load, each of said different signals comprising at least one interruption of the power supply waveform for a time period of less than one cycle of the waveform.

Claim 14

Apparatus for controlling loads within the premises of consumers on an alternating electrical power supply comprising, at each individual load to be controlled, means for detecting one out of a plurality of different signals broadcast over the power supply network within the premises of the associated consumer as distinguishable modifications of the power supply waveform, and switching means responsive to the detected signal for interrupting the power supply to the load, each of said different signals comprising at least one interruption of the power supply waveform for a time period of less than one cycle of the waveform.

Claim 15

Apparatus as claimed in claim 11 wherein said means for detecting one out of a plurality of different signals comprises means for detecting and counting the number of signals received as detectable modifications of the power supply waveform and wherein the switching means interrupts the power supply to the load in accordance with the magnitude of the count.

Claim 16

Apparatus as claimed in claim 12 wherein the means interrupting the power supply to the load comprises means comparing the counted number of received signals with a predetermined number and operative to switch off the supply to the load when the counted number equals said predetermined number.

Claim 17

Apparatus as claimed in claim 13 wherein the means interrupting the power supply to the load interrupts the power supply to the load for a predetermined time period and resets the counting means during or at the end of said predetermined time period.

Claim 18

An electricity supply system comprising an alternating electrical power supply generating means, signalling means arranged to interrupt the power supply waveform of said generating means for a short duration in selected cycles of the alternating waveform, the duration being small compared with the time duration of one cycle at the power supply frequency, a plurality of loads within the premises of individual consumers, means feeding the power supply with interrupted waveform to said loads, and at each load, means for detecting and counting the number of interruptions in the received power supply waveform in a predetermined time period, and means responsive to the counting of a predetermined number of interruptions for switching the power supply to said load.

Claim 19

An electricity supply system comprising an alternating electrical power supply generating means, signalling means arranged to interrupt the power supply waveform of said generating means for a short duration in selected cycles of the alternating waveform, the duration being small compared with the time duration of one cycle at the power supply frequency, a plurality of loads within the premises of individual consumers, means feeding the power supply with interrupted waveform to said loads, and at each load, means for detecting and counting the number of interruptions in the received power supply waveform in a predetermined time period, and means responsive to the counting of a predetermined number of interruptions for switching the power supply to said load.

Claim 20

Apparatus for use by a consumer for controlling individual loads within the premises of the consumer on an alternating electrical power supply comprising means for monitoring the overall demand placed on the power supply by the consumer, means for modifying the alternating power supply waveform by interruptiong the power supply for a short duration less than one cycle of the supply frequency to provide a signal representative of the overall demand on the power supply by the consumer when such demand exceeds a predetermined limit, and associated with the individual supply circuit to each load to be controlled, data processing means including means for detecting said signal, a counter, means operative in response to said signal to increment the count on said counter when the associated load is taking current, means operative to decrement the count on the counter in the absence of a further signal after a predetermined time, and switch means operative to switch off the individual load, or a part thereof, when the count in the counter exceeds a predetermined value.

Claim 21

Apparatus for use by a consumer for controlling individual loads within the premises of the consumer on an alternating electrical power supply comprising means for monitoring the overall demand placed on the power supply by the consumer, means for modifying the alternating power supply waveform by interruptiong the power supply for a short duration less than one cycle of the supply frequency to provide a signal representative of the overall demand on the power supply by the consumer when such demand exceeds a predetermined limit, and associated with the individual supply circuit to each load to be controlled, data processing means including means for detecting said signal, a counter, means operative in response to said signal to increment the count on said counter when the associated load is taking current, means operative to decrement the count on the counter in the absence of a further signal after a predetermined time, and switch means operative to switch off the individual load, or a part thereof, when the count in the counter exceeds a predetermined value.

Claim 22

Apparatus as claimed in claim 16 wherein different loads of a consumer are arranged to be switched off at different count numbers.

Claim 23

Apparatus for use by a consumer for controlling loads within the premises of the consumer on an alternating current power supply, to maintain the overall demand placed on the power supply by the consumer at or below a predetermined maximum demand, comprising means for sensing the overall demand placed on the power supply by the consumer and for determining when the sensed demand exceeds said maximum demand, means for applying a signal to the various loads by modifying the waveform of the power supply by interrupting the power supply for a short duration less than one cycle of the supply frequency when said maximum demand is exceeded and associated with or at each individual load on the various loads to be controlled, means for detecting said signals, a counter with circuit means for incrementing the count of the counter each time a signal is received and for decrementing the count of the counter in the absence of a signal for a predetermined time, switch means operative to interrupt the power supply to the individual load, or part thereof, when the count in the associated counter exceeds a predetermined magnitude, the predetermined magnitudes being different for a least some of the different individual loads, and means for operating the switch to restore the power supply to the individual load when the count is below the predetermined number for the individual load.

Claim 24

Apparatus for use by a consumer for controlling loads within the premises of the consumer on an alternating current power supply, to maintain the overall demand placed on the power supply by the consumer at or below a predetermined maximum demand, comprising means for sensing the overall demand placed on the power supply by the consumer and for determining when the sensed demand exceeds said maximum demand, means for applying a signal to the various loads by modifying the waveform of the power supply by interrupting the power supply for a short duration less than one cycle of the supply frequency when said maximum demand is exceeded and associated with or at each individual load on the various loads to be controlled, means for detecting said signals, a counter with circuit means for incrementing the count of the counter each time a signal is received and for decrementing the count of the counter in the absence of a signal for a predetermined time, switch means operative to interrupt the power supply to the individual load, or part thereof, when the count in the associated counter exceeds a predetermined magnitude, the predetermined magnitudes being different for a least some of the different individual loads, and means for operating the switch to restore the power supply to the individual load when the count is below the predetermined number for the individual load.

Claim 25

Apparatus as claimed in claim 16 wherein the switch means comprises a solid state switch at each individual load.

Claim 26

Apparatus as claimed in claim 16 wherein the means for modifying the power supply waveform to provide a signal comprises a solid state switching device to effect an interruption of the power supply for a time period small compared with the time duration of a cycle of the alternating power supply and logic means for controlling the solid state switching device in accordance with the monitored demand.

Claim 27

Apparatus as claimed in claim 20 wherein said monitoring means comprises a current transformer giving an output signal representative of the total demand current on the power supply, and analogue-to-digital conversion means to convert the output signal into a digital signal and wherein said logic means are arranged to compare the digital signal with a preset maximum demand magnitude and to operate the switching means in accordance with said comparison.

Claim 30

A method as claimed in claim 22 wherein the distinguishable signals comprise distinguishably different numbers of interruptions within a predetermined time period.

Claim 31

Apparatus for controlling loads on an electrical power supply comprising means for modifying the voltage by pulse interruptions of duration less than one cycle of the supply frequency to provide detectable control signals of a plurality of distinguishably different forms and at each individual load to be controlled means for detecting the control signals, means for selecting one of the detected signals, and means for controlling the load in accordance with the selected signal.

Claim 32

Apparatus for controlling loads on an electrical power supply comprising means for modifying the voltage by pulse interruptions of duration less than one cycle of the supply frequency to provide detectable control signals of a plurality of distinguishably different forms and at each individual load to be controlled means for detecting the control signals, means for selecting one of the detected signals, and means for controlling the load in accordance with the selected signal.

Claim 33

A method as claimed in claim 1 wherein the steps of monitoring and opening are performed at each consumers' premises.

Claim 34

A method as claimed in claim 6 wherein the steps of monitoring and modifying are performed at each consumers' premises.

Claim 35

Apparatus as claimed in claim 11 further comprising means for monitoring the power demand on the electrical power supply and means for broadcasting over the power supply network a signal indicative of the monitored demand.

Claim 36

Apparatus as claimed in claim 27 wherein said monitoring means and said broadcasting means are within the premises of the associated consumer.

Claim 37

A system as claimed in claim 15 wherein said signalling means is within the premises of the individual consumers.

Claim 38

Apparatus as claimed in claim 16 wherein said monitoring means and said modifying means are within the premises of the consumer.

Claim 39

Apparatus as claimed in claim 18 wherein said sensing and determining means and said applying means are within the premises of the consumer.

Claim 40

A method as claimed in claim 22 wherein the step of modifying is performed at each consumers' premises.

Claim 41

Apparatus as claimed in claim 24 wherein said modifying means is within the premises of the consumer.