GB2347225A - Electric utility meter with means to detect and report theft - Google Patents
Electric utility meter with means to detect and report theft Download PDFInfo
- Publication number
- GB2347225A GB2347225A GB0004408A GB0004408A GB2347225A GB 2347225 A GB2347225 A GB 2347225A GB 0004408 A GB0004408 A GB 0004408A GB 0004408 A GB0004408 A GB 0004408A GB 2347225 A GB2347225 A GB 2347225A
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- GB
- United Kingdom
- Prior art keywords
- electric utility
- utility meter
- theft
- meter
- current
- 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
- G01R22/00—Arrangements for measuring time integral of electric power or current, e.g. electricity meters
- G01R22/06—Arrangements for measuring time integral of electric power or current, e.g. electricity meters by electronic methods
- G01R22/061—Details of electronic electricity meters
- G01R22/066—Arrangements for avoiding or indicating fraudulent use
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R22/00—Arrangements for measuring time integral of electric power or current, e.g. electricity meters
- G01R22/06—Arrangements for measuring time integral of electric power or current, e.g. electricity meters by electronic methods
- G01R22/08—Arrangements for measuring time integral of electric power or current, e.g. electricity meters by electronic methods using analogue techniques
Abstract
An electric utility meter comprises a bypass wire detector, an external electromagnetic field detector, load current measuring means located before the main fuse and a data transfer card arrangement to transfer theft and other data back to the utility supplier. The electric bypass wire detector may include means of directing a known test current, at a frequency other than the fundamental or harmonics of the electric supply, through a current sensing arrangement. The current sensing arrangement may be used to measure the said test current which is then compared with the known test current value. A signal indicating the presence of a bypass wire is provided on detecting a difference between the measured and known current values. The external electromagnetic field detector may comprise electromagnetic field sensors placed around the utility meter and arranged to provide a signal when they detect an increase in the external magnetic field above a predetermined level. The said load current measuring means may be a current transformer or a Hall effect transducer and may include means of measuring the voltage across the live and neutral line inlets after the main fuse. The above detectors may be linked to respective tamper counters and a meter tamper counter which can provide data for transfer via a smart card reader on to a smart card. The serial number of the meter may also be transferred on to the smart card.
Description
The invention relates to an electric utility meter having commercially feasible means to detect electric utility theft and means to transfer electric utility theft information back to electric utility company
BACKGROUND OF THE INVENTION
Most electric utility companies encounter two difficulties. The first difficulty is the theft of electric utility. Two of the widely used methods of electric utility theft are tampering the intemal structure or design of electric utility meter and adding a bypass wire in parallel to the electric utility meter. A less common method of tampering electric utility meter is by inducing an externat strong EMF to interfere with electric utility consumption measurement. The second difficulty is the cost of human labour and other minor problems, such as fenced premises and dogs, associated with sending meter reader to collect measurement of electric utility consumption from each electric utility meter.
With the introduction of well-designed electronic electric utility meter, tampering of intemal structure or design of electric utility meter is no longer feasible. This leaves the option of electric utility theft by adding bypass wire and inducing strong EMF. Since it is not possible to prevent tampering of electric utility meter, the best solution is to detect attempts on electric utility theft and then transfer information on electric utility theft back to electric utility company.
The aspect leading to the present invention is to provide an electric utility meter that is capable of detecting bypass wire electric utility theft and external
EMF electric utility theft and then transfer information on detection of electric utility theft back to electric utility company efficiently at a low cost of implementation.
The present invention provides an electric utility meter having the means and apparatus to detect electric utility theft and to transfer information regarding detection of electric utility theft between electric utility meter and electric utility company at a much lower cost of implementation. The means of transferring information on detection of electric utility theft has also made sending human meter reader obsolete as the same means can be used to transfer other meter information such as serial number and accumulated electric utility measurement.
SUMMARY OF INVENTION
The prime objective of the present invention is to provide an electric utility meter having the means and apparatus to reduce electric utility theft and transfer information regarding detection of electric utility theft between electric utility meter and electric utility company at a much lower cost of implementation.
In an effort to reduce electric utility theft, the electric utility meter of present invention provides several means for detecting tampering on electric utility meter to steal electricity. The first means detects presence of bypass wire by continuously testing with a known current. A difference in known test current with the measured test current will indicate the presence of bypass wire.
Upon detecting presence of bypass wire, an accumulative bypass wire counter is incremented.
Electric utility meter of the present invention provides a second alternative means to reduce bypass wire by rearranging the conventional arrangement of electric utility meter. The said second means measures load current at a point before the main fuse to eliminate connection joints for attaching bypass wire.
Electric utility meter of the present invention provides a third means to detect deliberately induced strong external EMF that would interfere with normal operation of electric utility meter. Upon detection of presence of strong external EMF, an accumulative external EMF counter is incremented.
In an effort to provide a low cost and feasible implementation of transferring information, electric utility meter of the present invention provides a forth means to implement the transferring of information from electric utility meter back to electric utility company. Smart card technology is adopted to transfer the said information along with other electric utility meter information back to electric utility company. Since smart card is a fairly standard data storage media with certain extend of data security, it does not prevent illegal access, analysis and alteration to data stored within. Thus, by storing accumulative and non-reset able information, altering such data stored in the smart card will only delay the actual accumulated information from reaching electric utility company. At any instance of time, personnel from electric utility company can personally approach the electric utility meter and load the latest accumulated information back to electric utility company.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 illustrates the block diagram for electric utility meter of the present
invention.
Figure 2 illustrates the power supply circuit for operation of other circuit
components.
Figure 3 illustrates the block diagram of electric utility power calculation
circuit.
Figure 4 illustrates the buffer circuit for current transformer and potential
transformer.
Figure 5 illustrates the block diagram of bypass wire detection circuit using
One-Wire Configuration.
Figure 6 illustrates the circuit to generate a known test current to detect
bypass wire.
Figure 7 illustrates the amplifier circuit to detect known current injected into
current sensing wire.
Figure 8 illustrates the circuit to condition signal detected from known test
current before signaling main controller.
Figure 9 illustrates the amplifier circuit to detect test current flowing in current
sensing wire.
Figure 10 illustrates the circuit to condition signal detected from measured test
current before signaling main controller.
Figure 11 illustrates the block diagram of bypass wire detection circuit using
Two-Wire Configuration.
Figure 12 illustrates the block diagram of bypass wire detection circuit using
Three-Wire Configuration.
Figure 13 illustrates the block diagram of arrangement of extemal EMF
detection sensors around the load current measurement element.
Figure 14 illustrates the block diagram of externat EMF detection circuit.
Figure 15 illustrates the amplifier circuit to detect strong externat EMF.
Figure 16 illustrates the circuit to condition external EMF signal for indicating
proper circuit functionality.
Figure 17 illustrates the circuit to condition extemal EMF signal to indicate
detection of strong external EMF interference.
Figure 18 illustrates the block diagram of non-volatile memory storing electric
utility theft status and information.
Figure 19 illustrates the detail non-volatile memory storing bypass wire
counter.
Figure 20 illustrates the block diagram of alternative arrangement to electric
utility meter to hinder connection of bypass wire.
Figure 21 illustrates the procedure flow of monthly bill payment using
information transfer means of the present invention.
Figure 22 illustrates the circuit to implement interna smart card reader in
electric utility meter.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The following list indicates features related to description of the preferred embodiment of present invention:
10. Electric Utility Meter 10b. Alternative Arrangement Electric Utility Meter
120. Socket of Smart Card Reader
140. Current Sensing Wire at live line
141. Live Line Inlet from electric utility distribution grid
142. Live Line Outlet to electrical consumer products
143. Neutral Line Inlet from electric utility distribution grid
144. Neutral Line Outlet to electrical consumer products
145. Live Line Inlet Line Fastener
147. Neutral Line Inlet Line-Fastener 150. Known Test Current injected into current sensing wire
152. Measured Test Current flowing in current sensing wire
154. Load Current drawn by electric appliances
160. Non-Volatile Memory in for storing critical information
161. Electric Utility Meter Tamper Detected Counter
162. Accumulative Bypass Wire Detected Counter
162a. Accumulative Bypass Wire Detected Counter Word 1
162b. Accumulative Bypass Wire Detected Counter Word 2
164. Accumulative External EMF Detected Counter
166. Serial Number of Electric Utility Meter
168. Accumulated Electric Utility Measurement
1810. Electric Utility Measurement circuit
1811. Current Measurement Element
1812. Electromagnetic Current Transducer for measuring load
current 1813. Current Measurement Element Buffer 1814. Voltage Measurement Element 1815. Voltage Measurement Element Buffer 1816. Electric Power Calculation Circuit 1820. LCD Display Panel 1822. Power Supply Circuit 1823. Stepped-down AC supply voltage 1824. Step Down Transformer 1830. Bypass Wire Detection Circuit 1831. Known Test Current Generation Circuit 1832. Electromagnetic Current Transducer for measuring injected
known test current 1833. Electromagnetic Current Transducer for measuring test current
flowing in current sensing wire 1834a. Test Current Injection wire A 1834b. Test Current Injection wire B 1835. Known Test Current Amplifier Circuit 1835a. Known Test Current Signal A Circuit Node 1835b. Known Test Current Data Circuit Node 1835c. Known Test Current Reference Circuit Node 1836. Known Test Current Valid Indication Circuit 1836a. Known Test Current Data Circuit Node 1836b. Known Test Current Power Down Mute Circuit Node 1836c. Known Test Current Reference Circuit Node 1837. Measured Test Current Amplifier Circuit 1837a. Known Test Current Signal Circuit Node 1837b. Measured Test Current Data Circuit Node 1837c. Measured Test Current Reference Circuit Node 1838. Bypass Wire Detection Indication Circuit 1838a. Measured Test Current Data Circuit Node 1838b. Measured Test Current Power Down Mute Circuit Node 1838c. Measured Test Current Reference Circuit Node 1839. Differential Input Measured Test Current Amplifier Circuit 1840. External EMF Detection Circuit
1842. EMF Sensor to detect external EMF
1842a. EMF Sensor to detect an existing EMF as reference to ensure
circuit functionality
1844. EMF Amplifier Circuit
1844a. EMF Signal
1844b. EMF High Reference Signal
1844c. EMF Low Reference Signal
1846. EMF Signal Valid Indication Circuit
1846a. EMF Signal Data
1846b. EMF Signal Valid Reference Circuit Node
1846c. EMF Valid Power Down Mute Circuit Node
1846d. EMF Signal Data
1846e. EMF Detection Reference Circuit Node
1846f. EMF Detection Power Down Mute Circuit Node
1847. EMF Signal Detection Indication Circuit
1850. Main Controller
20. Smart Card for transferring data
30. Bypass Wire
32. External EMF to interfere with electric utility measurement
42. Live Incoming Electric Cable
44. Main Fuse
50. Electric Utility Counter for paying electric utility consumed
510. Computer Terminal at electric utility counter
512. Smart Card Reader attache to Computer Terminal at Electric
Utility Counter
520. Central Computer at electric utility company
522. Central Electric Utility Meter Data Storage in Central Computer
The prime objective of the present invention is to provide an electric utility meter having the means to detect and reduce electric utility theft and transfer information regarding detection of electric utility theft between electric utility meter and electric utility company at a much lower cost of implementation.
Figure 1 shows the block diagram of a single-phase electric utility meter [10].
Power circuit [1822] supplies regulated power supply for the
electronics of electric utility meter [10]. Electric utility measurement
circuit [1810] is composed of current element [1811], voltage
element [1814] and electric power calculation circuit [1816].
Current element [1811] measures load current [154] flowing in live
line inlet [1411 and live line outlet 1142]. Voltage element [1814]
measures voltage supply across live line inlet [141] and neutral line
inlet [143]. The accumulated instantaneous power calculated is
then transferred through main controller [1850] to be displayed on
LCD panel [1820]. Upon detection of main distribution grid failure,
the accumulated instantaneous power is stored in non-volatile
memory [160]. Apart from measurement consumption of electric
utility, this electric utility meter [10] has the means of detecting and
transferring electric utility theft information back to electric utility
company. The first means of detecting electric utility theft is to
detect connection of bypass wire [30] using bypass detection circuit
]. Upon presence of bypass wire [30], bypass wire detection
circuit [1830] signals main controller [1850] to increment
accumulative bypass wire counter [162] in non-volatile memory
[160]. The second means of detecting electric utility theft is to detect
strong external EMF [32] using externat EMF detection circuit
]. Upon presence of strong external EMF [32], extemal EMF
detection circuit [1840] signals main controller [1850] to increment
accumulative external EMF counter [164] in non-volatile memory [160]. When it is time to pay for electric utility consumption, smart
card [20] is inserted into smart card reader [120] for transferring
information between electric utility meter [10] and electric utility
company. This information include electric utility theft data such as
electric utility meter tamper detected counter [161], accumulative
bypass wire counter [162], accumulative external EMF counter
[162], serial number of electric utility meter [166] and accumulated
electric utility measurement [168].
Figure 2 shows the power supply circuit to the other electronic circuits. Step
down transformer T1 [1824] steps down alternating current, herein
abbreviated as AC, voltage from live inlet [141] and neutral inlet
[143]. The bridge rectifier B1 rectifies the AC voltage into direct
current, herein abbreviated as DC, voltage Vin [1823]. This voltage
Vin [1823] will be used in other circuits as power down muting
signal. Diode D1 isolates the Vin [1823] from DC voltage filtered by
capacitor C1. The value of capacitor C1 is typically large, around 1000uF, to provide necessary voltage supply to operate main
controller [1850] for saving important data into non-volatile memory
[160] after main distribution gird failure. Voltage regulator IC1 stabilizes the DC voltage filtered by capacitor C1 to a fixed 5V DC
Vcc voltage. Capacitor C2 provides high frequency filter for IC2
that gives a 2.5V reference voltage. This 2.5V reference voltage is
used as DC biasing voltage for current and voltage measurement.
Figure 3 shows implementation of electric power measurement circuit [1810].
Current transformer CT1 [1812] is used to implement the current
element [1811] circuit. Buffer circuit BF1 [1813] conditions signal
from current transformer CT1 [1812] for Analog-to-Digital Converter,
herein abbreviated as ADC, IC3. Potential transformer PT1 is used
for implementing voltage element circuit [1814]. Buffer circuit BF2
] conditions signal from potential transformer PT1 for ADC IC4. These two buffer circuits will protect ADC IC3 and IC4 from
over or under shoots. Digital Signal Processor, herein abbreviated
as DSP, IC5 reads data sampled by ADC IC3 and IC4 for
calculation of instantaneous electric power measurement.
Instantaneous electric power calculated from each sampling are
summed up to give the accumulated electric utility measurement
that reflects the total electric power consumed via the electric utility
meter [10].
Figure 4 shows implementation of buffer circuit for BF1 [1813] and BF2
]. Resistor R1 provides the necessary power conversion load
for both CT1 and PT1. Resistors R2 and R3 set the inverting gain
factor for the buffer circuit. The fact that this is an inverting buffer
circuit does not have real consequence to the electric power
calculation as long as both current element [1811] and voltage
element [1814] are in phase. Operational Amplifier IC6 chosen
must be of rail-to rail type operation and does not present phase
reversa characteristic.
Figure 5 shows a One-Wire Configuration of bypass wire detection circuit [1830]. As the name implies, this configuration requires only the
current sensing wire [140] to pass through current transformer [1833]. Test current circuit [1831l (for details, refer Figure 6)
generates a known AC current [150] that flows from test current
wire A [1834a], through current sensing wire [140] and return by
test current wire B [1834b] when bypass wire [30] is absent.
Current transformer [1832], test current amplifier circuit 1 [1835] (for
details, refer Figure 7) and Test current conditioning circuit 1 [1836] (for details, refer Figure 8) detects the known test current [150] to
validate the proper functionality of the bypass wire detection circuit [1830]. These circuits, [1835] and [1836], are designed such that if
current transformer [1832] is shorted or opened circuited, a test
current invalid signal will be sent to main controller [1850] for
incrementing the electric utility meter tamper detected counter
[161]. Current transformer [1833], test current differential amplifier
circuit 2 [1837] (for details, refer Figure 9), Test current conditioning
circuit 2 [1838] and signal from test current amplifier circuit 1 [1835] detects the test current [152] flowing in current sensing wire [140].
Any difference between injected test current [150] and the
measured test current [152] will trigger a signal to main controller
] indicating bypass wire present. During absence of bypass
wire [30], all the test current [150] will flow through current sensing
wire [140] thus, the measured test current [152] will be the same as
test current [150]. This causes both currents to cancel off each
other leaving no output. On the other hand, if bypass wire [30] does
present, part of the test current [150] will flow through bypass wire
[30] resulting in reduced measured test current [152]. Since both
test current [150] and measured test current [152] are different in
magnitude, the test current differential amplifier 2 [1837] will
produce a non-zero amplitude signal and thus triggering test current
conditioning circuit [1838] to signal main controller [140] that bypass
wire [30] is detected. Finally, current transformer [1812] is also
attached at the same current sensing wire [140]
Figure 6 shows a circuit that generates a fixed amplitude test current [150].
Resistor R4, capacitor C4 and Schmitt Triggered Inverter IC7 : E
form a basic oscillating circuit. Schmitt Triggered Inverter IC7 : F
operates as current buffer to drive a small test current through
capacitor C3, resistor R5, into test current wire A [1834a], through
current sensing wire [140] and back to test current wire B [1834b].
Capacitor C3 de-couples DC component of test current making it
purely AC. Resistor R5 sets the amplitude of the test current.
Figure 7 shows a circuit implementation of test current amplifier circuit 1 [1835]. Test current wire B [1834b] passes through current
transformer [1832]. Test current [150] flowing in test current wire B
[1834b] induced EMF around the wire and subsequently induces a
potential output from current transformer [1832]. Resistor R6 acts
as a load to convert current flowing from current transformer [1832] into voltage. Resistor R7, R8, capacitor C6, C7 and operational
amplifier IC8 : B forms a first stage bandpass filter operating at
fundamental frequency of test current [150]. This circuit allows high
amplification gain from input to output since test current is very
small in amplitude. Resistor R9, R10, capacitor C8, C9 and operational amplifier IC8 : A is a second stage bandpass filter
operating at fundamental frequency of test current [150]. Output
signal [1835a] from pin 1 of IC8 : A will be used as differential signal
to detect bypass wire [30] in test amplifier 2 circuit node [1837a]
(refer Figure 9). Resistor R11, R12, capacitor C10, C11 and
operational amplifier IC8 : D is a third stage bandpass filter operating
at fundamental frequency of test current [150]. Output data [1835b]
from pin 14 of IC8 : D will be connected to circuit node [1836a] in
Figure 8. Resistor R13, R14 and capacitor C5 form a bias voltage
for IC8 : A, IC8 : B and IC8 : D. Resistor R15 and R16 set a reference
voltage, Vref, [1835c] as the minimum level for amplitude of test
current [150]. This circuit node [1835c] is connected to circuit node [1836c] in Figure 8. Amplitude of test current [150] that results in a
reference voltage lower than Vref [1835c] indicates that the bypass
detection circuit [1830] is faulty.
Figure 8 shows a circuit implementation of test current signal conditioning
circuit 1 [1836]. Data output from pin 14 of IC8 : D [1835b] is an AC
signal. Diode D2, resistor R17, R18 and capacitor C12 converts
this AC data signal [1836a] into a DC signal to be compared to Vref [1836c]. Under normal condition, voltage at pin 10 of IC8 : C is
higher than Vref of pin 9 [1836c]. Thus, the output of IC8 : C
operational amplifier will be high. Diode D3, resistor R19, R20 and
capacitor C13 fifters glitches and noise from the output of pin 8
IC8 : C. Schmitt trigger inverters IC7 : B and IC7 : D recondition
voltage at pin 3 of IC7 : B to a full logic High output at pin 8 of IC7 : D.
When there is supply from main electric distribution grid, an AC
voltage is present at circuit node [1836b]. Diode D4 and capacitor
C14 converts the AC voltage into a DC voltage. With this DC
voltage present, resistor R22 and R23 will turn on transistor Q1.
Once transistor l turns on, this will enable the opto-isolator IC9 to
send signal to main controller [1850]. With output pin 8 of IC7 : D at
logic high, resistor R21 will then on the interna Light Emitting
Diode, herein abbreviated as LED, in IC9. This sends a low signal
to main controller [1850] indicating proper bypass circuit [1830] operation. If there is no supply from main distribution grid, AC
voltage at circuit node [1836b] will disappear, resulting transistor Q1 to turn off. This in turn triggers on transistor Q2 to discharge
voltage at pin 3 of IC7 : B. The purpose of this circuit is to ensure no
circuit malfunction during main distribution failure. If, however, that
test current [150] flowing in test wire B [1834b] has been tampered
with, either open or short circuited, then there will be no AC signal
at circuit node [1836a]. Voltage at pin 10 of IC8 : C is lower than
Vref of pin 9 [1836c], resulting in logic level low at output of pin 8 of
IC7 : D. Under normal condition, LED in IC9 will not turn on and
thus, logic high is sent to main controller [1850] indicating
malfunction in bypass wire detection circuit [1830].
Figure 9 shows a circuit implementation of test current amplifier circuit 2
]. Current sensing wire [140] passes through current
transformer [1833]. Measured test current [152] flowing in current
sensing wire [140] induces EMF around the wire and subsequently
induces a potential output from current transformer [1833]. Resistor
R26 acts as a load to convert current flowing from current
transformer [1833] into voltage. Resistor R27, R28, capacitor C16,
C17 and operational amplifier IC10 : B forms a first stage bandpass
filter operating at fundamental frequency of test current [150]. The
values of these resistors, capacitors and operational amplifier is the
same as used for resistor R7, R8, capacitor C6, C7 and IC8 : B
respectively (refer to Figure 7) to obtain the same amplification.
Resistor R29, R30, capacitor C18, C19 and operational amplifier IC10 : A is a second stage bandpass filter operating at fundamental
frequency of test current [150]. The values of these resistors,
capacitors and operational amplifier is the same as used for resistor
R9, R10, capacitor C8, C9 and IC8 : A respectively (refer to Figure 7)
to obtain the same amplification. Resistor R33, R34 and capacitor
C15 form a bias voltage for IC10 : A, IC10 : B and IC10 : D. Resistor
R35 and R36 set a reference voltage, Vref2, [1837c] as the
maximum level for allowable difference between amplitude of test
current [150] and measured test current [152]. This node [1837c] is
connected to circuit node 1838c in Figure 10. Resistor R31, R32,
R37, R38 and operational amplifier IC10 : D form a voltage
subtracting circuit. Resistor R31 has the same value as resistor
R37, while resistor R32 has the same value as resistor R38. If
bypass wire [30] is absent, the voltage at pin 1 of IC10 : A is the
same as voltage at circuit node [1837a]. Output pin 14 [1837b] of IC10 : D will be almost a DC signal. If bypass wire [30] is present, the
voltage at pin 1 of IC10 : A is different from voltage at circuit node [1837a]. Output pin 14 [1837b] of IC10 : D will be an AC signal. This
output node [1837b] is connected to a signal conditioning circuit
node [1838a] in Figure 10.
Figure 10 shows a circuit implementation of test current signal conditioning
circuit 2 [1838]. Basically, the entire operation of circuit is identical
to test current signal conditioning circuit [1836]. The only difference
is that during absence of bypass wire [30], a DC voltage at circuit
node [1838a] gives a voltage at pin 10 of IC10 : C lower than voltage
reference set at circuit node [1838c]. This results in logic low at
output of pin 8 of IC18 : D. IC19 will send logic high to main
controller [1850] indicating bypass wire [30] absent. However, with
bypass wire [30] present, an AC signal significantly large in
amplitude appears at circuit node [1838a].-Voltage at pin 10 of IC10 : C will be higher than voltage reference set at circuit node
[1838c] giving logic High at output of pin 8 of IC18 : D. IC19 will
signal a logic low to main controller [1850] indicating bypass wire [10] present.
Figure 11 shows a Two-Wire Configuration of bypass wire detection circuit [1830]. As the name impies, this configuration has the current
sensing wire [140] and neutral line passing through current
transformer [1833]. The rest of the circuit is identical to One-Wire
Configuration bypass wire detection circuit [1830] except for the
setting of reference voltage Vref. With One-Wire Configuration,
measured test current [152] has load current [154] added into it,
thus making the result of the circuit sensitive to load current [154] variation. Thus, One-Wire Configuration is prone to load current
[154] noise. With Two-Wire Configuration, the load current [154]
flowing in current sensing wire [140] is cancelled off by opposite
direction flow of load current [154] in neutral line, thus leaving
measured current [152] purely test current component only. The
Two-Wire Configuration is almost immune to load current [154]
noise.
Figure 12 shows a Three-Wire Configuration of bypass wire detection circuit [1830]. As the name impies, this configuration has the current
sensing wire [140], neutral line and test current wire [1834b]
passing through current transformer [1833]. This Three-Wire
Configuration is also almost immune to load current [154] noise as
in Two-Wire Configuration. The difference is instead of constantly
measuring a test current in current sensing wire, there will be no
test current measured [152] if bypass wire [30] is not connected.
This is because the test current [150] flowing in test current wire
[1834b] cancels off the test current flowing in current sensing wire [140]. When bypass wire [30] is present, the test current flowing in
current sensing wire [140] is less than test current [150] flowing in
test current wire [1834b], resulting in a non-zero net test current
measured by current transformer [1833]. The circuit to detect non
zero net test current [1839] is the same as the circuit used for test
current amplifier 1 [1835]. The signal conditioning circuit [1838] is
also the same as circuit for signal conditioning 1 [1836]. The only
difference is the reference voltage setting is not the same for Vref.
During absence of bypass wire [30] a logic High is sent to signal
main controller [1850] indicating no bypass wire present.
Conversely, presence of bypass wire [30] will cause a logic Low
signal sent to main controller [1850].
Figure 13 shows implementation of detecting external EMF [32] induced to
interfere with normal operation of electric utility meter [10],
especially on measurement of load current [154] by current
transformer [1812]. Several external EMF sensors [1842] are
placed around the electric utility meter [10] to sense external EMF
interference. A control EMF sensor [1842a] is placed close to step
down voltage transformer [1824] to make sure that there is no
illegal tampering to the external EMF detection circuit [1840].
Figure 14 shows implementation of detecting external EMF detection circuit
]. All the external EMF sensor [1842] and the control sensor [1842a], are connected in series and in phase to EMF amplifier
circuit [1844] (refer to Figure 15). From the EMF amplifier circuit [1844], two reference voltages are produced to set a window limit
whereby the total EMF measured by all EMF sensors lie within this
window limit. Too few EMF indicates tampering of EMF detection
circuit [1840] while too much EMF indicates existence of strong externat EMF interference. EMF signal conditioning circuit 1 [1846] signals main controller [1850] of validity in EMF detection circuit
]. EMF signal conditioning circuit 2 [1847] signals main
controller [1850] of detection of external EMF [32]. All the EMF
sensors can be easily built by looping copper tracks on printed
circuit boards.
Figure 15 shows a circuit implementation of EMF amplifier circuit [1844]. The
basic operation of circuit is almost the same as bypass wire
detection amplifier circuit [1835]. The difference is the center
bandwidth of bandpass filter is set at fundamental operating
frequency of main distribution grid. This is because the most
significant frequency component worth interfering with is the
fundamental frequency component of main distribution grid. Thus
resistor R40, R41, capacitor C21, C22 and operational amplifier IC11 : B is designed as first stage bandpass filter operating at center
frequency of main distribution grid. Resistor R42, R43, capacitor
C23, C24 and operational amplifier IC11 : A is designed as second
stage bandpass filter operating at center frequency of main
distribution grid. Resistor R39 provides a load to obtain an induced
voltage. Resistor R44, R45 and capacitor C20 set the bias voltage
for operation of IC11 : B and IC11 : A. Resistor R46, R47 and R48 set
two window limit reference voltages, namely EMFVref1 [1844b] and
EMFVref2 [1844c]. Output of pin IC11 : A represents the total EMF
detected by all EMF sensors. In normal operation this signal voltage [1844a] should lie within a window limit. Circuit node [1844a] is connected to circuit node [1846a] in Figure 16 and circuit
node [1846d] in Figure 17. EMFVref1 [1844b] and EMFVref2
[1844c] are connected to circuit node [1846e] in Figure 17 and
circuit node [1846b] in Figure 16 respectively.
Figure 16 shows implementation of signal conditioning circuit for indication of
valid EMF detection circuit [1840] operation. The basic operation of
this circuit is the same as signal conditioning circuit [1836]. During
absence or external EMF, voltage at pin 12 is higher than reference
voltage EMFVref2 [1846b]. This result in a logic low signal sent to
main controller [1850] indicating valid functionality of EMF detection
circuit. Upon disconnecting EMF sensors or short circuiting input to
EMF amplifier circuit, there will be DC signal at circuit node [1846a].
This results in logic low at output of pin 8 of IC12 : D. A logic high
signal is sent for-main controller [1850] to indicate tampering on
EMF detection circuit [1840].
Figure 17 shows implementation of signal conditioning circuit for indication of extemal EMF detected. The basic operation of circuit is the same
as valid EMF [1846]. When there is no presence of external EMF,
the signal level at circuit node 10 of pin IC11 : C is lower than circuit
node [1846e]. This result in high signal sent to main controller [1850] indicating absence of external EMF. If external EMF is
present, the signal level at circuit node 10 of pin IC11 : C is higher
than circuit node [1846e]. This result in low signal sent to main controller [1850] indicating present of externat EMF.
Figure 18 shows implementation of arranging non-volatile memory [160] to
store serial number [166], accumulated electric utility measurement [168], electric utility meter tamper detected counter [161], bypass
wire detected counter [162] and external EMF detected counter
[164]. These values are controlled by main controller [1850]. There
will be no means of resetting or decrement accumulated electric
utility measurement [168], electric utility meter tamper detected
counter [161], bypass wire detected counter [162] and external EMF
detected counter [164]. This protects the non-volatile memory [160] against illegal manipulation, especially on accumulated electric
utility measurement [168], electric utility meter tamper detected
counter [161], bypass wire detected counter [162] and external EMF
detected counter [164].
Figure 19 shows implementation of accumulative bypass wire detected
counter [162] in non-volatile memory [160]. The counter [162] is
divided into two words of 16 bits each, namely WORD1 [162a] and
WORD2 [162b]. When there is no detection of bypass wire [30], WORD1 [162a] has the same value to WORD2 [162b]. Upon
detection of bypass wire [30], value of WORD1 [162a] is checked
against WORD2 [162b]. If both having the same value, then value
of WORD1 [162a] is incremented by one. This will prevent multiple
detection of bypass wire [30] connection and multiple increment,
which could lead to uncertainty in validity of counter [162] values.
When smart card [20] is inserted into electric utility meter [10] to
update latest information, the value of WORD2 [162b] is equated to
value of WORD1 [162a]. This enables the detection of next bypass
wire [30] connection. Since each word is 16bits long, this will
enable a detection of bypass wire [30] presence 65,536 times
before the counter value rolls over back to the same value. This
means if an electric utility customer connects a bypass wire [30]
across the current sensing wire [140], he or she will have to slot the
smart card [20] in and out of electric utility meter [10] exactly 65,536
times every month in order not to be caught. Missing the cycle by
even one count will trigger the awareness of electric utility
company. The bit length of WORD1 [162a] and WORD2 [162b] can
be increased to have a larger count before the counter rolls back to
starting value. The same means is adapted to electric utility meter
tamper detected counter [161] and external EMF detected counter
[164].
Figure 20 shows implementation of alternative third means to reduce bypass
wire [30] electric utility theft. This implementation departs from
conventional arrangement of electric utility meter [10]. Instead of
measuring the load current [154] at a point after main fuse [44], this
means of present invention measures the load current [154] a point
before the main fuse [44]. The incoming electric cable [42] is
connected directly from main distribution grid, pass through current
transformer [1812] in the electric utility meter [10b] and connected
to main fuse [44]. There will only be one detachable point located
at main fuse [44]. This will force the attachment of bypass wire [30]
to be not feasible without using wire to wire midway terminal
connection. The electric utility voltage measurement is obtained
from live line inlet fastener [145] and neutral line inlet fastener [147].
For this implementation of electric utility meter [10b], it is important
for the inner hole diameter of current transformer [1812] to be large
enough for only one incoming electric cable [42] to pass through.
Figure 21 shows the procedure flow for transferring information between
electric utility meter [10] and electric utility company. Before electric
utility customer approach electric utility counter for payment of
monthly utility usage, the customer slots a smart card [20] into
smart card socket [120] built into to electric utility meter [10].
Electric utility theft information is loaded into smart card [20] so as
to be transferred to electric utility company without the knowledge of
customer. Other information of electric utility meter [10] such as
meter serial number [166] and accumulated electric utility
measurement [168] is also loaded into smart card [20]. Once
information loading has completed, electric utility customer takes
the smart card [20] to any authorized electric utility counter [50] to
pay for the latest utility consumption. When the smart card [20] is
inserted into smart card reader [512], all information loaded into
smart card [20] are transferred into computer terminal [510] at
electric utility counter [50]. The computer first checks if there is any
electric utility theft detected by electric utility meter [10]. If electric
utility theft has been detected, the electric utility customer is
referred to authorities from electric utility company for further
actions. Otherwise, the latest bill payment is calculated. All the
information read from smart card [20] will be updated into a central
computer [520] as reference for next bill calculation. Bill payment
validation command is set into smart card [20]. The electric utility
customer will then take the smart card [20] and slot it into smart
card socket [120] for validating electric utility meter [10] for next bill
payment calculation. The enables the electric utility meter [10] to
calculate interim bill payment for the coming month.
Figure 22 shows a circuit implementation of internal smart card reader built
into electric utility meter [10] for transferring of data between smart
card [20] and electric-utility meter [10]. Upon detection of smart
card [20], main controller [1850] starts transferring of data to and
from smart card [20] via smart card socket SC1 [120]
The features disclose in the above description or the accompanying drawings, expressed in their specific forms, are obvious to those skilled in the art to implement circuits of diverse forms that embodies the basic concepts of the present invention.
Claims (30)
- CLAIMS 1. An electric utility meter having method to reduce electric utility theft, comprising of: a) bypass wire detector for detection of connecting bypass wire in parallel across input and output of electric utility meter; b) electromagnetic field detector for detection of externally induced electromagnetic field ;c) meter rearrangement to measure load current at a point before the main fuse; and d) data transfer device using smart card to transfer electric utility theft data and other meter information back to electric utility company.
- 2. An electric utility meter having method to reduce electric utility theft as claimed in Claim 1 wherein bypass wire detector comprises means :- a) directing test current to flow into current sensing wire ; b) measuring said test current flowing in current sensing wire; c) comparing measured test current to said test current ; and d) signaling presence of bypass wire upon detecting a difference in measured test current compared to test current.
- 3. An electric utility meter having method to reduce electric utility theft as claimed in Claim 2 wherein the test current has fundamental frequency operating at frequency other than harmonics of fundamental frequency of electric utility.
- 4. An electric utility meter having method to reduce electric utility theft as claimed in Claim 2 wherein the test current has small amplitude.
- 5. An electric utility meter having method to reduce electric utility theft as claimed in Claim 4 wherein the amplitude of test current may be constant.
- 6. An electric utility meter having method to reduce electric utility theft as claimed in Claim 4 wherein the amplitude of test current may change at a fixed pattern.
- 7. An electric utility meter having method to reduce electric utility theft as claimed in Claim 4 wherein the amplitude of test current may change at a random pattern.
- 8. An electric utility meter having method to reduce electric utility theft as claimed in Claim 2 wherein the current sensing wire may be attache to live line.
- 9. An electric utility meter having method to reduce electric utility theft as claimed in Claim 2 wherein the current sensing wire may be attache to neutral line.
- 10. An electric utility meter having method to reduce electric utility theft as claimed in Claim 1 wherein electromagnetic field detector comprises means f : a) placing electromagnetic fields sensors around electric utility meter ; b) measuring externat electromagnetic field strength;c) comparing externat electromagnetic field strength against a predetermined level ; and d) signaling presence of external electromagnetic field upon detecting an increase of electromagnetic field strength above said predetermined level.
- 11. An electric utility meter having method to reduce electric utility theft as claimed in Claim 10 wherein external interfering electromagnetic field is a field that has strong magnitude capable of interfering with normal operation of electric utility meter.
- 12. An electric utility meter having method to reduce electric utility theft as claimed in Claim 10 wherein predetermined level is the acceptable electromagnetic field signal level before interfering with the normal operation of electric utility meter.
- 13. An electric utility meter having method to reduce electric utility theft as claimed in Claims 11 and 12 wherein normal operation of electric utility meter includes electric utility power calculation.
- 14. An electric utility meter having method to reduce electric utility theft as claimed in Claims 11 and 12 wherein normal operation of electric utility meter includes storage of data in volatile memory.
- 15. An electric utility meter having method to reduce electric utility theft as claimed in Claims 11 and 12 wherein normal operation of electric utility meter includes storage of data in non-volatile memory.
- 16. An electric utility meter having method to reduce electric utility theft as claimed in Claim 1 wherein meter rearrangement comprises means of: a) connecting first end of incoming electric cable to main electric distribution grid; b) passing incoming electric cable through current transducer of electric utility meter;c) connecting second end of incoming electric cable to main fuse; d) measuring load current flowing in incoming electric cable ; and measuring electric utility voltage across live line inlet and neutral line inlet after main fuse.
- 17. An electric utility meter having method to reduce electric utility theft as claimed in Claim 16 wherein incoming electric cable may be the live line.
- 18. An electric utility meter having method to reduce electric utility theft as claimed in Claim 16 wherein incoming electric cable may be the neutral line.
- 19. An electric utility meter having method to reduce electric utility theft as claimed in Claim 16 wherein current transducer can be current transformer.
- 20. An electric utility meter having method to reduce electric utility theft as claimed in Claim 16 wherein current transducer can be Hall-effect current transducer.
- 21. An electric utility meter having method to reduce electric utility theft as claimed in Claim 16 wherein current transducer must have an internal hole diameter just large enough for only one incoming electric cable to pass through.
- 22. An electric utility meter having method to reduce electric utility theft as claimed in Claim 1 wherein data transfer device comprises means of loading information in electric utility meter into smart card through smart card reader.
- 23. An electric utility meter having method to reduce electric utility theft as claimed in Claim 22 wherein information includes accumulated value of electric utility meter tamper counter.
- 24. An electric utility meter having method to reduce electric utility theft as claimed in Claim 22 wherein information includes accumulated value of bypass wire counter.
- 25. An electric utility meter having method to reduce electric utility theft as claimed in Claim 22 wherein information includes accumulated value of external electromagnetic field counter.
- 26. An electric utility meter having method to reduce electric utility theft as claimed in Claim 22 wherein information includes serial number of electric utility meter.
- 27. An electric utility meter having method to reduce electric utility theft as claimed in Claim 22 wherein information includes accumulated value of electric utility measured by electric utility meter.
- 28. An electric utility meter having method to reduce electric utility theft as claimed in Claim 1 wherein the electric utility meter can be a single phase electric utility meter.
- 29. An electric utility meter having method to reduce electric utility theft as claimed in Claim 1 wherein the electric utility meter can be a mufti-phase electric utility meter.
- 30. An arrangement of electric utility meter having method as in any of Claims 1 to 29.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| MYPI9900696 | 1999-02-25 | ||
| MYPI9901459 | 1999-04-15 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB0004408D0 GB0004408D0 (en) | 2000-04-12 |
| GB2347225A true GB2347225A (en) | 2000-08-30 |
Family
ID=26641538
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB0004408A Withdrawn GB2347225A (en) | 1999-02-25 | 2000-02-24 | Electric utility meter with means to detect and report theft |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JP2000249730A (en) |
| CN (1) | CN1264839A (en) |
| GB (1) | GB2347225A (en) |
| ID (1) | ID26815A (en) |
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| WO2002041012A1 (en) * | 2000-10-23 | 2002-05-23 | Austriamicrosystems Ag | Device for indicating manipulations of electricity meter connections |
| WO2003065055A2 (en) * | 2002-01-31 | 2003-08-07 | Iskraemeco, Merjenje In Upravljanje Energije, D.D. | Magnetic field detection system for an electricity meter |
| GB2391948A (en) * | 2002-08-15 | 2004-02-18 | Pri Ltd | Utility meter with magnetic field detection |
| WO2004034069A1 (en) * | 2002-10-10 | 2004-04-22 | Actaris Measurement And Systems (Proprietary) Limited | System for the control of reticulated services |
| CN102608373A (en) * | 2012-04-13 | 2012-07-25 | 钜泉光电科技(上海)股份有限公司 | Electric larceny detecting method and system, and electricity meter |
| EP2597473A1 (en) * | 2011-11-28 | 2013-05-29 | Schneider Electric Industries SAS | Method and device for detecting a shunt between the power input and output of an electricity consumption meter |
| RU2674513C1 (en) * | 2018-03-19 | 2018-12-11 | Олег Фёдорович Меньших | Half-wave circuit for the energy meters testing for the electric power uncontrolled takeoff |
| RU2691665C1 (en) * | 2018-01-23 | 2019-06-17 | Открытое акционерное общество "Авангард" | Method of measuring electric energy in two-wire networks with protection against theft and device for its implementation |
| RU2701448C1 (en) * | 2019-01-10 | 2019-09-26 | Олег Фёдорович Меньших | Half-wave circuit for testing electric power meters for uncontrolled power take-off |
| WO2019202075A1 (en) * | 2018-04-20 | 2019-10-24 | Sagemcom Energy & Telecom Sas | Electrical energy meter comprising a current-measuring circuit and a voltage-measuring circuit |
| US10931096B2 (en) | 2015-01-06 | 2021-02-23 | Techhold Llc | Systems and methods for actuating a transformer neutral blocking system |
| US10985559B2 (en) | 2017-02-03 | 2021-04-20 | Techhold Llc | Method and system for improved operation of power grid components in the presence of direct current (DC) |
| USRE48775E1 (en) * | 2010-07-20 | 2021-10-12 | Techhold, Llc | Self-testing features of sensing and control electronics for a power grid protection system |
| US11451047B2 (en) | 2017-03-30 | 2022-09-20 | Techhold, Llc | Protection of electrical devices based on electromagnetic pulse signal |
| US11820239B1 (en) * | 2022-07-20 | 2023-11-21 | Jan Morava | System and method for mitigation of intrusive electromagnetic fields |
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| JP4239677B2 (en) * | 2003-05-16 | 2009-03-18 | 株式会社日立製作所 | Electricity sales system to prevent theft of electricity |
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| CN102072977B (en) * | 2010-12-13 | 2016-04-20 | 国网河南省电力公司南阳供电公司 | The method of auto-breaking during intelligent electric energy meter stealing |
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| CN104155496A (en) * | 2014-04-23 | 2014-11-19 | 国家电网公司 | Electricity larceny prevention system and method |
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| CN106597356A (en) * | 2016-12-03 | 2017-04-26 | 国网江西省电力公司电力科学研究院 | Single-phase electric energy meter power frequency magnetic field influence quantity testing apparatus |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2002041012A1 (en) * | 2000-10-23 | 2002-05-23 | Austriamicrosystems Ag | Device for indicating manipulations of electricity meter connections |
| WO2003065055A2 (en) * | 2002-01-31 | 2003-08-07 | Iskraemeco, Merjenje In Upravljanje Energije, D.D. | Magnetic field detection system for an electricity meter |
| WO2003065055A3 (en) * | 2002-01-31 | 2004-03-18 | Iskraemeco Merjenje In Upravlj | Magnetic field detection system for an electricity meter |
| GB2391948A (en) * | 2002-08-15 | 2004-02-18 | Pri Ltd | Utility meter with magnetic field detection |
| WO2004017077A1 (en) * | 2002-08-15 | 2004-02-26 | Polymeters Response International Limited | Apparatus for detecting tampering with a utility meter |
| GB2391948B (en) * | 2002-08-15 | 2006-11-15 | Pri Ltd | Apparatus for detecting tampering with a utility meter |
| AU2003252966B2 (en) * | 2002-08-15 | 2008-07-17 | Secure International Holdings Pte. Ltd | Apparatus for detecting tampering with a utility meter |
| WO2004034069A1 (en) * | 2002-10-10 | 2004-04-22 | Actaris Measurement And Systems (Proprietary) Limited | System for the control of reticulated services |
| USRE48775E1 (en) * | 2010-07-20 | 2021-10-12 | Techhold, Llc | Self-testing features of sensing and control electronics for a power grid protection system |
| FR2983301A1 (en) * | 2011-11-28 | 2013-05-31 | Schneider Electric Ind Sas | METHOD AND DEVICE FOR DETECTING A SHUNT BETWEEN INPUT AND POWER OUTPUT OF AN ELECTRICAL CONSUMPTION COUNTER |
| EP2597473A1 (en) * | 2011-11-28 | 2013-05-29 | Schneider Electric Industries SAS | Method and device for detecting a shunt between the power input and output of an electricity consumption meter |
| CN102608373A (en) * | 2012-04-13 | 2012-07-25 | 钜泉光电科技(上海)股份有限公司 | Electric larceny detecting method and system, and electricity meter |
| US10931096B2 (en) | 2015-01-06 | 2021-02-23 | Techhold Llc | Systems and methods for actuating a transformer neutral blocking system |
| US10985559B2 (en) | 2017-02-03 | 2021-04-20 | Techhold Llc | Method and system for improved operation of power grid components in the presence of direct current (DC) |
| US11451047B2 (en) | 2017-03-30 | 2022-09-20 | Techhold, Llc | Protection of electrical devices based on electromagnetic pulse signal |
| RU2691665C1 (en) * | 2018-01-23 | 2019-06-17 | Открытое акционерное общество "Авангард" | Method of measuring electric energy in two-wire networks with protection against theft and device for its implementation |
| RU2674513C1 (en) * | 2018-03-19 | 2018-12-11 | Олег Фёдорович Меньших | Half-wave circuit for the energy meters testing for the electric power uncontrolled takeoff |
| WO2019202075A1 (en) * | 2018-04-20 | 2019-10-24 | Sagemcom Energy & Telecom Sas | Electrical energy meter comprising a current-measuring circuit and a voltage-measuring circuit |
| FR3080457A1 (en) * | 2018-04-20 | 2019-10-25 | Sagemcom Energy & Telecom Sas | ELECTRIC ENERGY METER COMPRISING A CURRENT MEASUREMENT CIRCUIT AND A VOLTAGE MEASUREMENT CIRCUIT |
| US10989744B2 (en) | 2018-04-20 | 2021-04-27 | Sagemcom Energy & Telecom Sas | Electrical energy meter comprising a current-measuring circuit and a voltage-measuring circuit |
| RU2701448C1 (en) * | 2019-01-10 | 2019-09-26 | Олег Фёдорович Меньших | Half-wave circuit for testing electric power meters for uncontrolled power take-off |
| US11820239B1 (en) * | 2022-07-20 | 2023-11-21 | Jan Morava | System and method for mitigation of intrusive electromagnetic fields |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1264839A (en) | 2000-08-30 |
| JP2000249730A (en) | 2000-09-14 |
| ID26815A (en) | 2001-02-08 |
| GB0004408D0 (en) | 2000-04-12 |
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