CA1120547A - Electricity metering apparatus allowing for time dependent differential rate structure - Google Patents
Electricity metering apparatus allowing for time dependent differential rate structureInfo
- Publication number
- CA1120547A CA1120547A CA000331387A CA331387A CA1120547A CA 1120547 A CA1120547 A CA 1120547A CA 000331387 A CA000331387 A CA 000331387A CA 331387 A CA331387 A CA 331387A CA 1120547 A CA1120547 A CA 1120547A
- Authority
- CA
- Canada
- Prior art keywords
- electricity
- registers
- pulses
- rate
- units
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R21/00—Arrangements for measuring electric power or power factor
- G01R21/133—Arrangements for measuring electric power or power factor by using digital technique
- G01R21/1333—Arrangements for measuring electric power or power factor by using digital technique adapted for special tariff measuring
- G01R21/1335—Tariff switching circuits
Abstract
ABSTRACT OF THE DISCLOSURE
The present invention provides electricity metering apparatus which, preferably, is designed in the form of an add-on attachment for a conventional watt-hour electricity meter.
sensor generates pulses, the repetition rate of which is dependent on the rate of consumption of units of electricity, and the total number of which determine the number of units of electricity consumed. The meter would provide indication of usage of power exceeding a preset limit. These pulse are fed selectively to one of a plurality of accumulator-registers which count and store the pulses by means of a gating circuit operating under the control of a control device. The control device gates the pulses to a selected one of the registers according to the time of day, day of the week, or season etc. so that each register counts the number of units consumed in the particular period associated with that register. In this manner, different charges may be made for different periods of the day etc., so as to encourage the consumer to use electricity at times when there is not a heavy demand on the electricity generating equipment. In this manner, the load curve can be flattened so as to reduce the total amount of generating capacity required.
The present invention provides electricity metering apparatus which, preferably, is designed in the form of an add-on attachment for a conventional watt-hour electricity meter.
sensor generates pulses, the repetition rate of which is dependent on the rate of consumption of units of electricity, and the total number of which determine the number of units of electricity consumed. The meter would provide indication of usage of power exceeding a preset limit. These pulse are fed selectively to one of a plurality of accumulator-registers which count and store the pulses by means of a gating circuit operating under the control of a control device. The control device gates the pulses to a selected one of the registers according to the time of day, day of the week, or season etc. so that each register counts the number of units consumed in the particular period associated with that register. In this manner, different charges may be made for different periods of the day etc., so as to encourage the consumer to use electricity at times when there is not a heavy demand on the electricity generating equipment. In this manner, the load curve can be flattened so as to reduce the total amount of generating capacity required.
Description
~Z~)5~7 - rrhe present invention r~lates to electricity meteriny apparatus allowing for time dependent difEerential ra-te structure. The apparatus may be incorporated, as an add-on unit, in~o conventional watt-hour electricity meters to allow for the number of units consumed in different selected periods to he recorded, The apparatus may be arranged such that the number of units consumed between, for example, 9 a.m. and 12 noon are recorded separately such that these units can be charged at a higher rate.
It has long been recognized that the supply of electricity represents a special problem in that, unlike other forms of energy, it cannot conveniently be stored in large quantities. The demand for electricity varies considerably during the course of a da~ and also varies according to the time of year.
The utility companies must ensure that they have adequate generating capacity to meet the demand at peak periods if black outs or voltage reductions are to be avoided, This means tha-t, during slack periods, the very expensive generatiny equipment is underused, This is an ineffective use oE costly plant and machinery.
It has been suggested that electricity should be charged at different rates according to the time of day so as to encourage consumers to increase the demand at off peak periods, with a consequential reduction in demand at peak periods. This flattening in the load curve would enable the same number of units of electricity to be generated with less expensive generating equipment, since the actual power output of the equipmen-~ could be reduced. For example, if, during a period of ten hours, 100 MWh of electricity are consumed at the rate of 91 MW/h and 1 MW/9h, a generator ~apable of producing 91 MW of electricity will have to be provided. However, during the remaining 9 hours, the generator is almost idle. On the other hand, if the ~ .
electricity can be provided at the rate of 10 ~ for ]0 hours, then only a 10 ~lW generator is needed and this can be run at maximum efficiency for the whole period. ~hese figures represent the principle behind load managementwhich involves, as far as possible, flattening out the demand curve so as to reduce the power output of the generating equipment for a given amount of units of electricit~.
In some areas, separate meters have been installed which are switched on between certain times by a timer and which lQ suppl~ certain appliances. For example, in Europe, a separate meter is often used to heat storage heaters which are heated up over night so that they retain their heat which is then dissipated during the day. These meters require separate circuits and the appliances connected to them cannot be used during the off periods. While it is desirable to encourage the consurner to use his or her appliances duriny certain periods by means of a diEferential xate structure, it rnay be unacceptable to prevent them from usiny th~:ir applianc~es in certain periods if they are prepared to accept the consequence and pay for the electricity at the higher rate.
An object of the present invention is to provide a simple device which may be used in conjunction with conventional electricty meters to allow for a time dependent differential rate structure.
Accordingly, the present invention provides in sin~le-rate electricity metering apparatus of the type comprising a casina containing an Rddy current disc rotatable in dependence on the rate of consumption of units of electricity and a counter mechan-ically coupled to said disc to display the total consumption of electricity, the improvement comprising an add-on attachment for adapting said apparatus for time-dependent multi~rate metering provided with sensor means responsive to the rotation of 1121~)5~
said disc to generate pulses, the repetition rate of which is dependent on the rate of rotation of said disc, a plurality of accumulator registers for counting and storing said pulses, a gating circuit for feeding said pulses to a selected one of said registers, control means associated with said gating circuit for selecting registers during predetermined periods such that the count in each of said registers is representative of the number of units of electricity consumed in respective said predetermined periods and display means associated with said -~ registers ~or displaying the number of said units ofelectricity consumed in each of said predetermined periods.
lZ05~7 In a preferred embodiment, the metering apparatus is in the form of an add-on unit for a conventional watt hour meter such as that known as the type CIS single phase watt hour meter of the Sangamo Company Limited of Canada. In this embodiment, the pulse generating means comprises a sensor for sensing the rotation of the Eddy current disc in the watt hour meter. For this purpose, a magnet may be provided on the periphery of the disc which operates with a pick up unit. Alternatively, other sensing means can be used such as a light beam which is reflected off the Eddy current disc and detected by suitable means such as a phototransistor. A black track, which is interrupted at one point, can be painted on the disc to ensure that one pulse is generated for each revolutlon of the disc.
The control means is preferably in the form of a micro-processor which enables the utili-ty company to adjust the periods which correspond to each reglster. Also, allowance can be made not only ~or periods c~uriny the course of a day, but also for certain seasons where demand is high. Although of less practical value in the home, seasonal adjustment can be valuable for commercial users who may be able to make appropriate adjustment in their use of electricity to obtain maximum benefit from reduced rates.
If required, a communication device can be provided to receive signals from a central unit which would enable the registers to be remotely interrogated and also, if desired, the program in the microp~ocessor to be altered.
The invention will be now described in more detail, by way of example only, with reference to the accompanying drawings, in which:
Fig. 1 is a simplified block diagram of a first embodiment of a time dependent electricity me-tering apparatus; and 5~
Fig. 2 is a block diagram of a second embodirnent o~
such an apparatus employing a microprocessor.
The apparatus shown in Fig. 1 is in simplified form and is illustrated mainly to exemplify the broad principles of the invention. In ~ig n 1, a conventional wa-tt hour meter 1, such as the CIS single phase watt hour meter of the Sangamo Company Limited of Canada includes a conventional Eddy current disc 2 which rotates in dependence upon the number of units of electricity being consumed. As is well known, the watt hour meter integrates the product of the voltage times the current to give a measure of the actual amount of energy con-sumed, as opposed to the rate of consumption or power which is measured in watts. The standard unit of electricity is normally the kilowatt hour which is the amount of energy con-sumed if electricity is supplied at the rate of 1 kw for one hour. A small magnet 3 is mounted on the periphery of the Eddy current disc 2 and cooperates with a ~etec-tor ~ which comprises a small pick up coil. As -the magnet 3 passe.s the pick up coil formlng the detector 4, a pulse is generated.
Consec~uently, the total number of pulses generated is repre-sentative of the amount of electricity consumed in kilowatt hours.
The detector 4 is connected to a pulse shaping circuit 5 which is adapted to make the pulses suitable for the Jogic circuitry of the apparatus. The pulse shaper is connected to first inputs of respective AND gates 6 and 7 which are con-nected to respective accumu]ator registers 8 and 9. The registers 8 and 9 are connected through a switch device 30 to a light emitting diode display 111. Alterna-tively, display 111 may be a fluorescent display.
Second inputs of the AND gate 6 and 7 are connected ,~'~;, ' ~z~
respectively to the Q and Q outputs of a reset flip-flop 10.
A crystal oscillator 11 is connected to a chain of dividers 12 which divide the frequency of the oscillator 11 so as to produce -4a-.~ ~
one pulse per hour. The pulses are counted in a counter 13 which is automatically reset when the count reaches 24 so as to start a new day. In this example, the five parallel outputs of the counter 13 read the hour of the day in binar~ code. In this example, outputs 1 and 3 and ~ and 5 are connected to respective NO~ gates 14 and 15. The outputs of NOR gates 14 and lS are connected to the inputs of a NOR gate 16 whose output is connected with the output 2 from the counter to the input of a NOR gate 17.
This arrangement will provide a binary 1 output only when the count reads 01000, or 8 a.m. The parallel outputs are also connected to a second set of gates such that the second and third, and fourth and fifth outputs are connected to respective NOR
gates 18 and 19. The outputs of the NOR gates 18 and 19 are connected to inputs of an AND gate 20 whose output is connected to the input an AND gate 21 having its second input connected to the output 1 of the counter 13. This arrangement will ~ead a binary 1 when the output of the counter reads 10000, or 1600 hours.
The 1ip-flop 10 is a NOR yate flip flop such that when the A
input e~uals 1 and the B input e~uals 0, i.e. at g a.m., the Q oul:put goes to ~ and the Q output goes to a 0 which opens the AND gate 6 and feeds the pulses in the pulse shaper S into the accumulator register 8. At 9 a.m. when the A input goes to 0, the flip-flop 10 remains in the same state. At 1600 hours, the B input goes to a 1 which changes the Q output to a 0 and the Q output to a 1 which closes the AND gate 6 and feeds -the pulses from the pulse shaper 5 through the AND gate 7 to the accumulator register 9. At 1700 hours, the B input goes to a 0, but the flip-flop 10 remains in the same state until changed over again at ~ a.m.
Thus, it will be seen that, in operation, pulses from the pulse shaper 5, representative of the total number of units being consumed by the consumer, are fed through one of the AND
gates 7 or 8 to a respective one oE the accumulator reyisters 8 and 9 according to whether it is between 8 a.~. and 1600 hours or between 1600 hours and 8 a.m. These two registers -thus accumulate the total number of units consumed in -those periods.
When the meter reader arrives, he merely couples the accumulator registers 8 and 9, in turn, through the switch device 30 and suitable decoders (not shown) to the LED display 11. In this way, he will have a reading which will give him the total number of units consumed in each of these two periods. If necessary, a simple reset device (not shown) can be provided to reset the accumulator registers to 0. Alterna-tively, they can simply continue counting so that the meter reader will merely subtract the last reading from the new reading when he next reads the ~ meter to establish the number of units consumed. Fig. 1 has ; only been described to exemplify the invention and, in order to change the times, it would be necessary to change the logic circuitry associate~ with the counter 13.
In the embo~imerlt o~. Fig. 2, the apparatus is controlled by means o a microprocessor. As in the embodiment shown in Fig. 1, the small magnet 3 on the periphexy of the Eddy current disc 2 forming part of the watt hour meter 1 cooperates with a pick up coil in detector 4 to yenerate pulses each time the Eddy current disc rotates. The pulses are applied to the pulse shaper 5 which feeds them to a gating circuit 22. The output of the gating circuit 22 is connected to four accumulator registers 8, 3, 23 and 24, the outputs of which are in turn connected to a second gating circuit 29 which is connected to the LED display 11 through suitable decoding circuits (not shown).
A clock 24 provides an output representative o`f the time in hours and minutes. It also has ou-tputs representative of the day of the week, the month, the season an~ ~ y other time related parameter. The clock comprises a b~s~ oscillator with S~7 appropriate divider chains and counters for gene~a-tiny ~icJn~ls which determine the be~inning and end of the predete~mined time periods. If desired, the basic main frequency can be used as the reference frequency for the divider chain, instead of using a separate oscillator. The clock 24 is programmed to take into account day light saving time and also make adjust-ments for leap years in a manner which is well known for con-ventional oscillator driven watches. The clock 24 is connect-ed to a control unit 25 which, in turn, is connected to a program selector 26. The program selector 26 is shown connect-ed to a communications device 27 although this connection is optional. Communications devices communicates with a central office either by means of radio frequency transmission or, alternatively, by means of coded ripple signals impressed on the malns ~C waveform. The communications device 27 is also connected to a register selector 28 which is connected to the gating circuit 29.
In operation, the control unit 25, which is in the form of a microproc~s~or, is set up by means of the proyrammer 26 ko direct pulses Erom the detector 4 through the gating circui-t 26 to a selected one of the regis-ters ~, 9, 23, 2~
according to the time of day, day of the week, or season etc.
In the example shown, there are four registers, allowing for four different rate structures. However, only two registers - may be needed if there are only two rates, namely a peak and off peak rates. In the latter event, tne pulses could be directed to the off peak register during certain times of the day during the wee]c and all day during the weekends. To simplify the circuitry of the apparatus, the program selector 26 can be in the form of a separa-te portable unit ~hich is carried by the meter reader and simply connected to the ~'' control unit Z5 only when it is desired to set up -the initial program.
The registers 8, 9, 23 and 24 accumulate the total number of pulses fed into them and thus provide a measure of the -7a~
number of units consumed duriny the perlod assoc.iated ~ith each register and selected by the control unit 25. When it is desired to read the meter, each register is selected in turn by means of the register selector 28 which controls the gating circuit 23 and the contents of the register is read out on the LED display The meter reader ~an se~uentially read out the number o~
units consumed in the meter reading ~eriod, for example, during a peak period in the mornings, during week day afternoons, during week ends, and during low load periods during the night. As described so far, the meter reader will visit the premises of the consumer and control the apparatus by means of the program selector 26 and register selector 28. In fact, once the program had been set up, unless the utility company decided to change the periods in terms of which their rates were defined, there would be no need to change the program in the microprocessor 25.
The meter reader would simply read out the contents of the various registers by means of the register selector 28. The meter re~der can reset the regist0rs 8, 9, 23, 2~ or, alternative~y, they can be made of suff.iciently large capacity such that the.~ continue to count in the same manner as a conventioal electricity meter, with the reader simply noting the contents of the register at each reading.
In the more advanced version, use may be made of the communications device 27 which allows for remote signalling to the central office. Coded ripple signals may be impressed on the mains supply so that the personnel at the central office can interrogate the device installed at each consumer's premises remotely and, if necessary, change the program :in the control unit 25. The gating circuit is also connected to the communlcations device so that the reading in each of the registers can be transmitted bac~ to the central office without the need for utility company personnel visiting the consumer's premises at each 7~
meter readincJ.
Since -the registers 8, 9, 23, and Z4 are likely ko be volatile memories, in order to ensure that their contents are not lost during a power failure, when the apparatus is powered by the main supply, an auxiliary power source in the form of a battery i5 provided. This is normally charged by the main supply to ensure that it will always be in a full state of charge so as to take over in the event of such a failure.
The communications device may also be connected to switching relays (not shown) which allow the central office to switch off certain heavy duty appliances during emergencies or at peak load periods.
The apparatus described is constructed in the form of an add-on module which may be readily fitted to a standard conventional electricity watt hour meter. The pulses are derived simply from the rotation of the Eddy current disc in the watt hour meter which, in the embodiments described, is merely provided with a small magnet which generates pulses :in the pick up coil ~.
The existing electricity meter does not therefore have to be replaced, but the apparatus merely forms a simple add-on attachment which can be readily carried out by utility company personnel.
In fact, the physical dimensions of the module are selected such that they fit conveniently onto the front of a standard conventional electricity meter, preferably the Sangamo CIS type meter.
It would be appreciated that the apparatus described relies on the generation of a series of pulses, the repetition rate of which is dependent on the rate of consumption of electricity and the total number of which are representative of the number of units of electricity consumed. Clearly, there are many ways of generating such a series of pulses and, it could be done by means of wholly solid state circuitry. However, with _g_ the add-on apparatu~ desar:i.bed, there are many other conven:i~n~
ways of generating pulses from the rotation of the ~dd~ current disc or from the conventional watt hour meker. The detector 4, which was described as a simple pick up coil, can be in the form of a Hall effect probe. Alternatively, instead of using magnetic couplings, a light beam can be reflected from the surface of the disc. For this purpose, a black circle could be painted on the disc which is interrupted on one point. A light beam, generated from a light emitting diode, is reflected onto the black circle and a deteetor, such as a photodiode or phototransistor, is placed so as to receive the light being reflected off the surface o the disc. Of course, the black circle absorbs most of the light except where the interruption occurs and, as the disc rotates and the interruption comes into the appropriate position, the detector detects the light beam and generates a pulse. This method does not involve adding a magnet to the Eddy current disc.
In a conventional electricity meter, oE course, the Eddy current disc, drives a meehanical regi.ster through a gear train. Pulses from the apparatus aan, if desired, be der:ived from the movement of this gear tra:in~ For example, a p.i.n can be fixecd to one of the gears and arranged to open or close a pair of electrical contacts. Alternatively, the pin may be fixed directly to the Eddy current disc. Additionally, in the optical embodiment, a small hole may be drilled in the Eddy current disc to pass the light beam when the hole is in the appropriate place.
In the embodiment shown in Fig. 2, the control unit 25 and the clock 24 are shown as sepaxate units. However, a single microprocessor is now available which allows these functions to be combined on a single LSI (large scale integration) chip and this is available under the name ~o~oRO~ CQEL ~C ~
Furthermore, as describecl, the apparatus only reacls out the number of units of electricity consumed in a given number of ~10--preselected periods. If desired, additional LED displays can be provided which read out the current tarif rate associated with each period and, accordingly, each register. These displays will be d*iven by the microprocessor 25 and the rate associated with each register at the time would be programmed into the micro-processor. Indeed, if desired, additional registers can be provided which, instead of simply accumulating the total number of units consumed, accumulate the total charge associated with each charge period. Of course, the microprocessor, in this case, would have to be reprogrammed each time the tarif rate was changed in order to ensure the reading of these registers was correct. With the communications device 27, of course, the charge rates could be changed as appropriate from the central office.
The displays, such as the display 11, have been described as LED (light emitting diode) displays~ ~ut of course they could ec~ually well be LCD (li~uid cxystal) or any other corlvenient form of display.
In view oE the state of the art in logic circuitry design, all the components, including the accumulator registers, may be arranged on a single LSI chip and form part of the micro-processor which is shown, in Fig. 2, as only constituting the control unit.
It has long been recognized that the supply of electricity represents a special problem in that, unlike other forms of energy, it cannot conveniently be stored in large quantities. The demand for electricity varies considerably during the course of a da~ and also varies according to the time of year.
The utility companies must ensure that they have adequate generating capacity to meet the demand at peak periods if black outs or voltage reductions are to be avoided, This means tha-t, during slack periods, the very expensive generatiny equipment is underused, This is an ineffective use oE costly plant and machinery.
It has been suggested that electricity should be charged at different rates according to the time of day so as to encourage consumers to increase the demand at off peak periods, with a consequential reduction in demand at peak periods. This flattening in the load curve would enable the same number of units of electricity to be generated with less expensive generating equipment, since the actual power output of the equipmen-~ could be reduced. For example, if, during a period of ten hours, 100 MWh of electricity are consumed at the rate of 91 MW/h and 1 MW/9h, a generator ~apable of producing 91 MW of electricity will have to be provided. However, during the remaining 9 hours, the generator is almost idle. On the other hand, if the ~ .
electricity can be provided at the rate of 10 ~ for ]0 hours, then only a 10 ~lW generator is needed and this can be run at maximum efficiency for the whole period. ~hese figures represent the principle behind load managementwhich involves, as far as possible, flattening out the demand curve so as to reduce the power output of the generating equipment for a given amount of units of electricit~.
In some areas, separate meters have been installed which are switched on between certain times by a timer and which lQ suppl~ certain appliances. For example, in Europe, a separate meter is often used to heat storage heaters which are heated up over night so that they retain their heat which is then dissipated during the day. These meters require separate circuits and the appliances connected to them cannot be used during the off periods. While it is desirable to encourage the consurner to use his or her appliances duriny certain periods by means of a diEferential xate structure, it rnay be unacceptable to prevent them from usiny th~:ir applianc~es in certain periods if they are prepared to accept the consequence and pay for the electricity at the higher rate.
An object of the present invention is to provide a simple device which may be used in conjunction with conventional electricty meters to allow for a time dependent differential rate structure.
Accordingly, the present invention provides in sin~le-rate electricity metering apparatus of the type comprising a casina containing an Rddy current disc rotatable in dependence on the rate of consumption of units of electricity and a counter mechan-ically coupled to said disc to display the total consumption of electricity, the improvement comprising an add-on attachment for adapting said apparatus for time-dependent multi~rate metering provided with sensor means responsive to the rotation of 1121~)5~
said disc to generate pulses, the repetition rate of which is dependent on the rate of rotation of said disc, a plurality of accumulator registers for counting and storing said pulses, a gating circuit for feeding said pulses to a selected one of said registers, control means associated with said gating circuit for selecting registers during predetermined periods such that the count in each of said registers is representative of the number of units of electricity consumed in respective said predetermined periods and display means associated with said -~ registers ~or displaying the number of said units ofelectricity consumed in each of said predetermined periods.
lZ05~7 In a preferred embodiment, the metering apparatus is in the form of an add-on unit for a conventional watt hour meter such as that known as the type CIS single phase watt hour meter of the Sangamo Company Limited of Canada. In this embodiment, the pulse generating means comprises a sensor for sensing the rotation of the Eddy current disc in the watt hour meter. For this purpose, a magnet may be provided on the periphery of the disc which operates with a pick up unit. Alternatively, other sensing means can be used such as a light beam which is reflected off the Eddy current disc and detected by suitable means such as a phototransistor. A black track, which is interrupted at one point, can be painted on the disc to ensure that one pulse is generated for each revolutlon of the disc.
The control means is preferably in the form of a micro-processor which enables the utili-ty company to adjust the periods which correspond to each reglster. Also, allowance can be made not only ~or periods c~uriny the course of a day, but also for certain seasons where demand is high. Although of less practical value in the home, seasonal adjustment can be valuable for commercial users who may be able to make appropriate adjustment in their use of electricity to obtain maximum benefit from reduced rates.
If required, a communication device can be provided to receive signals from a central unit which would enable the registers to be remotely interrogated and also, if desired, the program in the microp~ocessor to be altered.
The invention will be now described in more detail, by way of example only, with reference to the accompanying drawings, in which:
Fig. 1 is a simplified block diagram of a first embodiment of a time dependent electricity me-tering apparatus; and 5~
Fig. 2 is a block diagram of a second embodirnent o~
such an apparatus employing a microprocessor.
The apparatus shown in Fig. 1 is in simplified form and is illustrated mainly to exemplify the broad principles of the invention. In ~ig n 1, a conventional wa-tt hour meter 1, such as the CIS single phase watt hour meter of the Sangamo Company Limited of Canada includes a conventional Eddy current disc 2 which rotates in dependence upon the number of units of electricity being consumed. As is well known, the watt hour meter integrates the product of the voltage times the current to give a measure of the actual amount of energy con-sumed, as opposed to the rate of consumption or power which is measured in watts. The standard unit of electricity is normally the kilowatt hour which is the amount of energy con-sumed if electricity is supplied at the rate of 1 kw for one hour. A small magnet 3 is mounted on the periphery of the Eddy current disc 2 and cooperates with a ~etec-tor ~ which comprises a small pick up coil. As -the magnet 3 passe.s the pick up coil formlng the detector 4, a pulse is generated.
Consec~uently, the total number of pulses generated is repre-sentative of the amount of electricity consumed in kilowatt hours.
The detector 4 is connected to a pulse shaping circuit 5 which is adapted to make the pulses suitable for the Jogic circuitry of the apparatus. The pulse shaper is connected to first inputs of respective AND gates 6 and 7 which are con-nected to respective accumu]ator registers 8 and 9. The registers 8 and 9 are connected through a switch device 30 to a light emitting diode display 111. Alterna-tively, display 111 may be a fluorescent display.
Second inputs of the AND gate 6 and 7 are connected ,~'~;, ' ~z~
respectively to the Q and Q outputs of a reset flip-flop 10.
A crystal oscillator 11 is connected to a chain of dividers 12 which divide the frequency of the oscillator 11 so as to produce -4a-.~ ~
one pulse per hour. The pulses are counted in a counter 13 which is automatically reset when the count reaches 24 so as to start a new day. In this example, the five parallel outputs of the counter 13 read the hour of the day in binar~ code. In this example, outputs 1 and 3 and ~ and 5 are connected to respective NO~ gates 14 and 15. The outputs of NOR gates 14 and lS are connected to the inputs of a NOR gate 16 whose output is connected with the output 2 from the counter to the input of a NOR gate 17.
This arrangement will provide a binary 1 output only when the count reads 01000, or 8 a.m. The parallel outputs are also connected to a second set of gates such that the second and third, and fourth and fifth outputs are connected to respective NOR
gates 18 and 19. The outputs of the NOR gates 18 and 19 are connected to inputs of an AND gate 20 whose output is connected to the input an AND gate 21 having its second input connected to the output 1 of the counter 13. This arrangement will ~ead a binary 1 when the output of the counter reads 10000, or 1600 hours.
The 1ip-flop 10 is a NOR yate flip flop such that when the A
input e~uals 1 and the B input e~uals 0, i.e. at g a.m., the Q oul:put goes to ~ and the Q output goes to a 0 which opens the AND gate 6 and feeds the pulses in the pulse shaper S into the accumulator register 8. At 9 a.m. when the A input goes to 0, the flip-flop 10 remains in the same state. At 1600 hours, the B input goes to a 1 which changes the Q output to a 0 and the Q output to a 1 which closes the AND gate 6 and feeds -the pulses from the pulse shaper 5 through the AND gate 7 to the accumulator register 9. At 1700 hours, the B input goes to a 0, but the flip-flop 10 remains in the same state until changed over again at ~ a.m.
Thus, it will be seen that, in operation, pulses from the pulse shaper 5, representative of the total number of units being consumed by the consumer, are fed through one of the AND
gates 7 or 8 to a respective one oE the accumulator reyisters 8 and 9 according to whether it is between 8 a.~. and 1600 hours or between 1600 hours and 8 a.m. These two registers -thus accumulate the total number of units consumed in -those periods.
When the meter reader arrives, he merely couples the accumulator registers 8 and 9, in turn, through the switch device 30 and suitable decoders (not shown) to the LED display 11. In this way, he will have a reading which will give him the total number of units consumed in each of these two periods. If necessary, a simple reset device (not shown) can be provided to reset the accumulator registers to 0. Alterna-tively, they can simply continue counting so that the meter reader will merely subtract the last reading from the new reading when he next reads the ~ meter to establish the number of units consumed. Fig. 1 has ; only been described to exemplify the invention and, in order to change the times, it would be necessary to change the logic circuitry associate~ with the counter 13.
In the embo~imerlt o~. Fig. 2, the apparatus is controlled by means o a microprocessor. As in the embodiment shown in Fig. 1, the small magnet 3 on the periphexy of the Eddy current disc 2 forming part of the watt hour meter 1 cooperates with a pick up coil in detector 4 to yenerate pulses each time the Eddy current disc rotates. The pulses are applied to the pulse shaper 5 which feeds them to a gating circuit 22. The output of the gating circuit 22 is connected to four accumulator registers 8, 3, 23 and 24, the outputs of which are in turn connected to a second gating circuit 29 which is connected to the LED display 11 through suitable decoding circuits (not shown).
A clock 24 provides an output representative o`f the time in hours and minutes. It also has ou-tputs representative of the day of the week, the month, the season an~ ~ y other time related parameter. The clock comprises a b~s~ oscillator with S~7 appropriate divider chains and counters for gene~a-tiny ~icJn~ls which determine the be~inning and end of the predete~mined time periods. If desired, the basic main frequency can be used as the reference frequency for the divider chain, instead of using a separate oscillator. The clock 24 is programmed to take into account day light saving time and also make adjust-ments for leap years in a manner which is well known for con-ventional oscillator driven watches. The clock 24 is connect-ed to a control unit 25 which, in turn, is connected to a program selector 26. The program selector 26 is shown connect-ed to a communications device 27 although this connection is optional. Communications devices communicates with a central office either by means of radio frequency transmission or, alternatively, by means of coded ripple signals impressed on the malns ~C waveform. The communications device 27 is also connected to a register selector 28 which is connected to the gating circuit 29.
In operation, the control unit 25, which is in the form of a microproc~s~or, is set up by means of the proyrammer 26 ko direct pulses Erom the detector 4 through the gating circui-t 26 to a selected one of the regis-ters ~, 9, 23, 2~
according to the time of day, day of the week, or season etc.
In the example shown, there are four registers, allowing for four different rate structures. However, only two registers - may be needed if there are only two rates, namely a peak and off peak rates. In the latter event, tne pulses could be directed to the off peak register during certain times of the day during the wee]c and all day during the weekends. To simplify the circuitry of the apparatus, the program selector 26 can be in the form of a separa-te portable unit ~hich is carried by the meter reader and simply connected to the ~'' control unit Z5 only when it is desired to set up -the initial program.
The registers 8, 9, 23 and 24 accumulate the total number of pulses fed into them and thus provide a measure of the -7a~
number of units consumed duriny the perlod assoc.iated ~ith each register and selected by the control unit 25. When it is desired to read the meter, each register is selected in turn by means of the register selector 28 which controls the gating circuit 23 and the contents of the register is read out on the LED display The meter reader ~an se~uentially read out the number o~
units consumed in the meter reading ~eriod, for example, during a peak period in the mornings, during week day afternoons, during week ends, and during low load periods during the night. As described so far, the meter reader will visit the premises of the consumer and control the apparatus by means of the program selector 26 and register selector 28. In fact, once the program had been set up, unless the utility company decided to change the periods in terms of which their rates were defined, there would be no need to change the program in the microprocessor 25.
The meter reader would simply read out the contents of the various registers by means of the register selector 28. The meter re~der can reset the regist0rs 8, 9, 23, 2~ or, alternative~y, they can be made of suff.iciently large capacity such that the.~ continue to count in the same manner as a conventioal electricity meter, with the reader simply noting the contents of the register at each reading.
In the more advanced version, use may be made of the communications device 27 which allows for remote signalling to the central office. Coded ripple signals may be impressed on the mains supply so that the personnel at the central office can interrogate the device installed at each consumer's premises remotely and, if necessary, change the program :in the control unit 25. The gating circuit is also connected to the communlcations device so that the reading in each of the registers can be transmitted bac~ to the central office without the need for utility company personnel visiting the consumer's premises at each 7~
meter readincJ.
Since -the registers 8, 9, 23, and Z4 are likely ko be volatile memories, in order to ensure that their contents are not lost during a power failure, when the apparatus is powered by the main supply, an auxiliary power source in the form of a battery i5 provided. This is normally charged by the main supply to ensure that it will always be in a full state of charge so as to take over in the event of such a failure.
The communications device may also be connected to switching relays (not shown) which allow the central office to switch off certain heavy duty appliances during emergencies or at peak load periods.
The apparatus described is constructed in the form of an add-on module which may be readily fitted to a standard conventional electricity watt hour meter. The pulses are derived simply from the rotation of the Eddy current disc in the watt hour meter which, in the embodiments described, is merely provided with a small magnet which generates pulses :in the pick up coil ~.
The existing electricity meter does not therefore have to be replaced, but the apparatus merely forms a simple add-on attachment which can be readily carried out by utility company personnel.
In fact, the physical dimensions of the module are selected such that they fit conveniently onto the front of a standard conventional electricity meter, preferably the Sangamo CIS type meter.
It would be appreciated that the apparatus described relies on the generation of a series of pulses, the repetition rate of which is dependent on the rate of consumption of electricity and the total number of which are representative of the number of units of electricity consumed. Clearly, there are many ways of generating such a series of pulses and, it could be done by means of wholly solid state circuitry. However, with _g_ the add-on apparatu~ desar:i.bed, there are many other conven:i~n~
ways of generating pulses from the rotation of the ~dd~ current disc or from the conventional watt hour meker. The detector 4, which was described as a simple pick up coil, can be in the form of a Hall effect probe. Alternatively, instead of using magnetic couplings, a light beam can be reflected from the surface of the disc. For this purpose, a black circle could be painted on the disc which is interrupted on one point. A light beam, generated from a light emitting diode, is reflected onto the black circle and a deteetor, such as a photodiode or phototransistor, is placed so as to receive the light being reflected off the surface o the disc. Of course, the black circle absorbs most of the light except where the interruption occurs and, as the disc rotates and the interruption comes into the appropriate position, the detector detects the light beam and generates a pulse. This method does not involve adding a magnet to the Eddy current disc.
In a conventional electricity meter, oE course, the Eddy current disc, drives a meehanical regi.ster through a gear train. Pulses from the apparatus aan, if desired, be der:ived from the movement of this gear tra:in~ For example, a p.i.n can be fixecd to one of the gears and arranged to open or close a pair of electrical contacts. Alternatively, the pin may be fixed directly to the Eddy current disc. Additionally, in the optical embodiment, a small hole may be drilled in the Eddy current disc to pass the light beam when the hole is in the appropriate place.
In the embodiment shown in Fig. 2, the control unit 25 and the clock 24 are shown as sepaxate units. However, a single microprocessor is now available which allows these functions to be combined on a single LSI (large scale integration) chip and this is available under the name ~o~oRO~ CQEL ~C ~
Furthermore, as describecl, the apparatus only reacls out the number of units of electricity consumed in a given number of ~10--preselected periods. If desired, additional LED displays can be provided which read out the current tarif rate associated with each period and, accordingly, each register. These displays will be d*iven by the microprocessor 25 and the rate associated with each register at the time would be programmed into the micro-processor. Indeed, if desired, additional registers can be provided which, instead of simply accumulating the total number of units consumed, accumulate the total charge associated with each charge period. Of course, the microprocessor, in this case, would have to be reprogrammed each time the tarif rate was changed in order to ensure the reading of these registers was correct. With the communications device 27, of course, the charge rates could be changed as appropriate from the central office.
The displays, such as the display 11, have been described as LED (light emitting diode) displays~ ~ut of course they could ec~ually well be LCD (li~uid cxystal) or any other corlvenient form of display.
In view oE the state of the art in logic circuitry design, all the components, including the accumulator registers, may be arranged on a single LSI chip and form part of the micro-processor which is shown, in Fig. 2, as only constituting the control unit.
Claims (20)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. In single-rate electricity metering apparatus of the type comprising a casing containing an Eddy current disc rotatable in dependence on the rate of consumption of units of electricity and a counter mechanically coupled to said disc to display the total consumption of electricity, the improvement comprising an add-on attachment for adapting said apparatus for time-dependent multi-rate metering provided with sensor means responsive to the rotation of said disc to generate pulses, the repetition rate of which is dependent on the rate of rotation of said disc, a plurality of accumulator registers for counting and storing said pulses, a gating circuit for feeding said pulses to a selected one of said registers, con-trol means associated with said gating circuit for selecting registers during predetermined periods such that the count in each of said registers is representative of the number of units of electricity consumed in respective said predetermined per-iods and display means associated with said registers for dis-playing the number of said units of electricity consumed in each of said predetermined periods.
2. Apparatus according to claim 1, wherein said sensor means comprises a magnetic pick up coil cooperating with a small magnet attached to the Eddy current disc of the apparatus.
3. Apparatus according to claim 1, wherein the sensor means is a Hall effect device cooperating with the Eddy current disc of the apparatus.
4. Apparatus according to claim 1, wherein the sensor means is a light beam detector for detecting a light beam transmitted through, or reflected from the surface of the Eddy current disc.
5. Apparatus according to claim 4, wherein the light beam detector is a phototransistor.
6. Apparatus according to claim 4, wherein the light beam detector is a photodiode.
7. Apparatus according to claim 1, wherein -the sensor means is in the form of a set of contacts actuated by the rotation of said Eddy current disc.
8. Apparatus according to claim 1, wherein a common display means is connected to each of the registers through a gating circuit and selector means are provided to enable the contents of each of the registers to be displayed selectively in said display means.
9. Apparatus according to claim 1, wherein said display means is in the form of a light emitting diode display.
10. Apparatus according to claim 1, wherein said display means is in the form of a liquid crystal display.
11. Apparatus according to claim 1, wherein said control means includes a crystal-oscillator driven clock for generating signals which determine the beginning and end of said predetermined periods.
12. Apparatus according to claim 11, wherein said control means is in the form of a microprocessor.
13. Apparatus according to claim 12, comprising program selector means connected to said microprocessor for enabling said preselected periods to be varied as desired.
14. Apparatus according to claim 1, wherein said accumulator registers, said gating circuit, and said control means form part of a common microprocessor.
15. Apparatus according to claim 1, comprising means for displaying the charge rate associated with each register.
16. Apparatus according to claim 1, comprising additional accumulator registers, connected to said control means, for accumulating the total charge associated with each said preselected period.
17. Electricity metering apparatus according to claim 1, further comprising communication means for transmitting and receiving signals to and from a remote central office.
18. Apparatus according to claim 17, wherein said communication means is coupled to said registers and said control means to enable said preselected periods to be varied remotely from the central office and to enable the contents of said registers to be read remotely at said central office.
19. Apparatus according to claim 17, further comprising means connected to said communications means for enabling certain circuits to be disconnected by said central office on command.
20. Apparatus according to claim 1, wherein said display means is a fluorescent display.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000331387A CA1120547A (en) | 1979-07-09 | 1979-07-09 | Electricity metering apparatus allowing for time dependent differential rate structure |
| GB7937533A GB2053538B (en) | 1979-07-09 | 1979-10-30 | Multi-tariff meter |
| DE19792944660 DE2944660A1 (en) | 1979-07-09 | 1979-11-06 | ELECTRICITY METER FOR PERIODIC APPLICATION OF DIFFERENT TARIFFS |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000331387A CA1120547A (en) | 1979-07-09 | 1979-07-09 | Electricity metering apparatus allowing for time dependent differential rate structure |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1120547A true CA1120547A (en) | 1982-03-23 |
Family
ID=4114638
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000331387A Expired CA1120547A (en) | 1979-07-09 | 1979-07-09 | Electricity metering apparatus allowing for time dependent differential rate structure |
Country Status (3)
| Country | Link |
|---|---|
| CA (1) | CA1120547A (en) |
| DE (1) | DE2944660A1 (en) |
| GB (1) | GB2053538B (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2148565B (en) * | 1983-10-20 | 1987-07-22 | Jel Energy Conservation Servic | Monitoring devices |
| DE69228850T2 (en) * | 1991-09-24 | 1999-10-07 | Gen Electric | Convertible energy meter |
| ES2043555B1 (en) * | 1992-05-29 | 1994-07-01 | Alcatel Standard Electrica | ELECTRIC ENERGY CONSUMPTION CONTROLLER. |
| CN114530014B (en) * | 2021-12-23 | 2023-05-23 | 杭州明特科技有限公司 | Electric energy meter, cost control method and system |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CH568568A5 (en) * | 1973-11-19 | 1975-10-31 | Landis & Gyr Ag | |
| US4050020A (en) * | 1976-09-17 | 1977-09-20 | General Electric Company | Multiple rate electrical energy metering system and method |
| DE2745436A1 (en) * | 1977-10-08 | 1979-04-12 | Licentia Gmbh | TARIFF DEVICE IN CONNECTION WITH AN ELECTRICITY COUNTER AND SEVERAL METERING DEVICES |
-
1979
- 1979-07-09 CA CA000331387A patent/CA1120547A/en not_active Expired
- 1979-10-30 GB GB7937533A patent/GB2053538B/en not_active Expired
- 1979-11-06 DE DE19792944660 patent/DE2944660A1/en not_active Ceased
Also Published As
| Publication number | Publication date |
|---|---|
| GB2053538B (en) | 1984-08-30 |
| DE2944660A1 (en) | 1981-02-05 |
| GB2053538A (en) | 1981-02-04 |
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