NZ601721B - Voltage-modifying device for electric meter - Google Patents
Voltage-modifying device for electric meter Download PDFInfo
- Publication number
- NZ601721B NZ601721B NZ601721A NZ60172112A NZ601721B NZ 601721 B NZ601721 B NZ 601721B NZ 601721 A NZ601721 A NZ 601721A NZ 60172112 A NZ60172112 A NZ 60172112A NZ 601721 B NZ601721 B NZ 601721B
- Authority
- NZ
- New Zealand
- Prior art keywords
- voltage
- electric meter
- modifying device
- power supply
- phase
- Prior art date
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- 230000005611 electricity Effects 0.000 claims abstract description 7
- 230000001052 transient Effects 0.000 claims description 7
- 238000010586 diagram Methods 0.000 description 14
- 239000003990 capacitor Substances 0.000 description 12
- 238000001914 filtration Methods 0.000 description 12
- 238000000926 separation method Methods 0.000 description 11
- 230000001264 neutralization Effects 0.000 description 4
- 230000005540 biological transmission Effects 0.000 description 3
- 238000001514 detection method Methods 0.000 description 3
- 238000007599 discharging Methods 0.000 description 2
- 230000005669 field effect Effects 0.000 description 2
- 230000002262 irrigation Effects 0.000 description 2
- 238000003973 irrigation Methods 0.000 description 2
- 239000004065 semiconductor Substances 0.000 description 2
- 230000000694 effects Effects 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 230000000135 prohibitive Effects 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R15/00—Details of measuring arrangements of the types provided for in groups G01R17/00 - G01R29/00, G01R33/00 - G01R33/26 or G01R35/00
- G01R15/08—Circuits for altering the measuring range
-
- 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
-
- 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
Abstract
601721 Disclosed is a system (100) for measuring electricity. The system (100) is comprised of an electric meter (30) having a housing; and a voltage-modifying device (20) connected to the electric meter (30) for modifying a received voltage. The voltage-modifying device (20) is provided to allow the electric meter (30) to operate in accordance with a predetermined power supply requirement. The voltage-modifying device (20) is located within the electric meter housing or is external to the electric meter housing. The electric meter (30) further includes an adaptor terminal (101) configured to connect to the voltage modifying device (20) to provide voltage feedback relating to at least one received phase to the electric meter (30). the electric meter (30) to operate in accordance with a predetermined power supply requirement. The voltage-modifying device (20) is located within the electric meter housing or is external to the electric meter housing. The electric meter (30) further includes an adaptor terminal (101) configured to connect to the voltage modifying device (20) to provide voltage feedback relating to at least one received phase to the electric meter (30).
Description
VOLTAGE-MODIFYING DEVICE FOR ELECTRIC METER
This application claims priority from United States Application No. 13/210,499
filed on 16 August 2011, the contents of which are to be taken as incorporated herein by this
reference.
BACKGROUND OF THE INVENTION
The subject matter disclosed herein relates generally to a voltage-modifying device.
More specifically, the present disclosure relates to a voltage-modifying device for an electric
meter that provides higher voltage capability, lower voltage capability and/or high voltage
transient protection.
Generally, electricity distribution is the final stage in the delivery of electricity to
customers. In a typical electrical distribution system (e.g., electrical sub-stations, power lines,
pole-mounted transformers, distribution wiring, electric energy meters, etc.), the electrical
distribution system carries the electricity generated from a transmission system (e.g., power
plant, transformers, high voltage transmission lines, etc.) and supplies the electricity to
customers via an electric meter.
In industrial applications, there is a wide range of applicable power supplies. For
example, in the U.S., industrial application power supplies range from 120 volts (V) to 480 V.
Approximately ninety-seven percent of these applications fall within the 120V to 277V range.
Therefore, only approximately three percent of the industrial applications require 480 V Delta
configurations. Additionally, systems for oil and irrigation applications require 480 V with
substantial transients due to long transmission lines and motor starts or stops. In Canada,
industrial application power supplies require 600 V. There are also a small percentage of
applications that require 57V to 120V. It is cost prohibitive to qualify a new meter for each
specific power supply requirement at these lower volumes. Further, it may require extensive
development time to qualify these new meters.
A reference herein to a patent document or other matter which is given as prior art
is not to be taken as an admission that that document or matter was known or that the
information it contains was part of the common general knowledge as at the priority date of
any of the claims.
BRIEF DESCRIPTION OF THE INVENTION
Aspects of the invention provide for qualifying a new meter with specific power
supply requirements.
A first aspect of the invention provides a system for measuring electricity,
comprising: an electric meter having a housing; and a voltage-modifying device connected to
the electric meter for modifying a received voltage, such that the electric meter operates in
accordance with a predetermined power supply requirement, wherein the voltage-modifying
device is located within the electric meter housing or external to the electric meter housing; the
electric meter further comprising an adapter terminal configured to connect to the voltage
modifying device to provide voltage feedback for at least one received phase to the electric
meter.
A second aspect of the invention provides a system, comprising: a power supply;
an electric meter including an electronic board within a housing; and a voltage-modifying
device connected to the electronic board and the power supply, the voltage-modifying device
for modifying a received voltage from the power supply, such that the electric meter operates
in accordance with a predetermined power supply requirement, wherein the voltage-modifying
device is located within the electric meter housing or external to the electric meter housing.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other features of this invention will be more readily understood from the
following detailed description of the various aspects of the invention taken in conjunction with
the accompanying drawings that depict various embodiments of the invention, in which:
shows a schematic diagram of a system according to aspects of the
invention;
shows a more detailed schematic diagram of a voltage-modifying device of
a system according to aspects of the invention;
shows a more detailed schematic diagram of a voltage-modifying device of
a system according to aspects of the invention;
shows a more detailed schematic diagram of a voltage-modifying device of
a system according to aspects of the invention;
shows a more detailed schematic diagram of a voltage-modifying device of
a system according to aspects of the invention;
shows a more detailed schematic diagram of a voltage-modifying device of
a system according to aspects of the invention;
shows a more detailed schematic diagram of a voltage-modifying device of
a system according to aspects of the invention;
It is noted that the drawings of the invention are not to scale. The drawings are
intended to depict only typical aspects of the invention, and therefore should not be considered
as limiting the scope of the invention. In the drawings, like numbering represents like
elements between the drawings.
DETAILED DESCRIPTION OF THE INVENTION
Aspects of the invention provide for qualifying a new meter with specific power
supply requirements. In one embodiment, aspects of the invention include a system,
including: an electric meter having a housing; and a voltage-modifying device connected to
the electric meter for modifying a received voltage, such that the electric meter operates in
accordance with a predetermined power supply requirement, wherein the voltage-modifying
device is located within the electric meter housing or external to the electric meter housing.
For example, as mentioned above, power supplies for industrial applications range
from 120V to 480V. However, only approximately ninety-seven percent of these applications
require 120V to 277V. It is more cost effective to design a 120V to 277V power supply
instead of a 120V to 480V power supply The voltage-modifying device, according to aspects
of the invention, enables a 120V to 277V power supply to be used for applications from 120V
to 480V. Further, in oil and irrigation applications that require 480V Delta systems,
overvoltage can often occur, which results in voltage transient problems. The voltage-
modifying device described herein provides protection against high voltage transients.
Therefore, it is not required to fully re-qualify a new meter for a specific power supply
requirement of each application.
Turning to FIGS. 1 and 2, a schematic diagram of a system 100 according to
aspects of the invention is shown. A power supply 10 may be connected to a voltage-
modifying device 20. Voltage-modifying device 20 may be connected to an electronic board
(not shown) of an electric meter 30. Although not shown, the electric meter 30 includes a
housing. As will be described below, the voltage-modifying device 20 enables the electric
meter 30 to operate in accordance with a predetermined power supply requirement. Although
it is not shown, it is understood that the voltage-modifying device 20 may be located within
the housing of the electric meter 30 or external to the electric meter 30.
System 100 will be described with respect to a three-phase power supply system.
Accordingly, three lines (i.e., phases) connect the power supply 10 to the voltage-modifying
device 20. An optional neutral line 107 is shown, that includes a resistor 108. An additional
line (an adapter terminal) 101 connects the voltage-modifying device 20 to the electric meter
. As will be described herein, the adapter terminal 101 provides voltage feedback and
supply separation for the meter 30.
Although system 100, as described herein, is applied to a three-phase power supply
system, it is understood that the applications of system 100 may be applied to any now known
or later developed power supply system.
Turning now to a more detailed schematic diagram of the voltage-
modifying device 20 of system 100 is shown. System 100, and voltage-modifying device 20,
is show including a first phase 102, a second phase 104, and a third phase 106. There may be
an additional wire for neutral; however, the neutral wire has been omitted for clarity purposes.
An adapter terminal 101 connects the voltage-modifying device 20 to the electric meter 30
(. As will be described herein, the adapter terminal 101 provides voltage feedback and
supply separation for the meter 30.
As seen in voltage-modifying device 20 includes a Surge protection circuit
40 connected to first phase 102 and second phase 104. Surge protection circuit 40 includes a
surge resistor 42 coupled in series with at least one varistor 44. shows Surge protection
circuit 40 including two varistors 44; however, it is understood that Surge protection circuit 40
may include any number of varistors 44. Varistor 44 may include a metal oxide varistor, or
any now known or later developed type of varistor. Varistor 44 is used to protect against
excess transient voltages by shunting the current created by the high voltage away from other
parts of the circuit.
Voltage-modifying device 20 includes an electromagnetic interference (EMI)
filtering device 60 coupled in series with the Surge protection circuit 40. EMI is a disturbance
that can affect the operation of the electrical circuitry within the voltage-modifying device 20
by interrupting, obstructing, or limiting the effect performance of the circuit. Examples of
EMI filtering devices that may be used include a common mode choke, an x-capacitor, or an
inductor and capacitor (“LC”) filter. However, other EMI filtering devices, as known in the
art, may be used.
In this embodiment of voltage-modifying device 20 includes an overvoltage
protection module 70. Overvoltage protection module 70 is configured to turn off power to
the electric meter 30 ( in response to receiving a voltage that exceeds the predetermined
power supply requirement. For example, a 120 V-480 V meter may turn off the power supply
voltage to the switch power mode in order to protect it when there is a voltage more than
480V.
An overvoltage detection circuit 72, within the overvoltage protection module 70,
detects when an overvoltage occurs. In response to an overvoltage occurring, the overvoltage
detection circuit 72 turns on the overvoltage protection module 70. In the embodiment shown
in the overvoltage protection module 70 includes a diode 71 electrically connected in
series with a varistor 73, a diode 74, and a metal-oxide-semiconductor field-effect transistor
(MOSFET) 75, which are electrically connected in parallel. The overvoltage protection
module 70 also includes a capacitor 76. However, it is understood that overvoltage protection
module may include any devices necessary to turn off power to the electric meter (, in
response to an overvoltage that exceeds the predetermined power supply requirement.
At least one additional resistor 77 may be provided for voltage feedback. For
example, an additional resistor 77 is shown in to provide voltage feedback of the first
phase 102 to the meter 30 ( through the adapter terminal 101. This additional resistor
77 also provides a separate terminal 101 off of the first phase 102 in order to provide supply
separation. A second additional resistor 78 may also be provided for voltage feedback and
supply separation for the third phase 106. In this embodiment, the second phase 104 passes
through EMI filtering device 60 and is used as a reference potential. This is often the case for a
half-wave rectification system.
Turning now to a detailed schematic diagram of an alternative embodiment
of the voltage-modifying device 20 in is shown. In this embodiment, a third additional
resistor 79 is provided for the second phase 104. As with the first additional resistor 77 for the
first phase 102 and the second additional resistor 78 for the third phase 106, this third
additional resistor 79 provides voltage feedback and supply separation for the second phase
104. In this embodiment, the second phase 104 passes through the EMI filtering device 60.
Turning now to a detailed schematic diagram of an alternative embodiment
of the voltage-modifying device 20 is shown. In this embodiment, the voltage-modifying
device 20 includes a high voltage module 80 (or step-down circuit) coupled in series with the
EMI filtering device 60. High voltage module 80 is configured to decrease a received voltage
in response to the receiving a voltage that exceeds the predetermined power supply
requirement. For example, the meter may be a 120 V-277 V meter and the voltage-modifying
device 20 is configured to so that meter is compatible with higher voltage lines, such as, 600 V
lines.
A buck control circuit 82, within the high voltage module 80, regulates and reduces
the voltage to a voltage level that is compatible with the meter 30. For example, for a 120V-
277V meter that is connected to 600V lines, the buck control circuit 82, within the voltage-
modifying device 20, will reduce the voltage to a voltage that is compatible with the 120V-
277V meter. As known to one of ordinary skill in the art, the buck converter includes two
switches (a diode 81 and a switch 83), an inductor 84, and a capacitor 85. The two switches
81, 83 alternate between charging the inductor 84 and discharging the inductor 84 to decrease
the voltage. It is understood that other configurations of a buck converter, as known in the art,
may be used in high voltage module 80.
As seen in the high voltage module 80 may include other electrical circuit
components, such as an additional diode 86 and an additional capacitor 87. These may be
known as half-wave rectification elements. However, it is understood that the high voltage
module 80 may include any devices necessary to decrease the voltage to the electric meter
(, in response to a voltage that exceeds the predetermined power supply requirement.
Similar to the embodiment shown in at least one additional resistor 77 may
be provided for voltage feedback. For example, an additional resistor 77 is shown in to
provide voltage feedback of the first phase 102 to the meter 30 ( through the adapter
terminal 101. The additional resistor 77 also increases the voltage divider ratio of the voltage
feedback. This additional resistor 77 also provides a separate terminal 101 off of the first
phase 102 in order to provide supply separation. A second additional resistor 78 may also be
provided for voltage feedback and supply separation for the third phase 106. In this
embodiment, the second phase 104 does not pass through the EMI filtering device 60.
Turning now to a detailed schematic diagram of an alternative embodiment
of the voltage-modifying device 20 in is shown. In this embodiment, a third additional
resistor 79 is provided for the second phase 104. As with the first additional resistor 77 for the
first phase 102 and the second additional resistor 78 for the third phase 106, this third
additional resistor 79 provides voltage feedback and supply separation for the second phase
104. In this embodiment, the second phase 104 passes through the EMI filtering device 60.
Turning now to a detailed schematic diagram of an alternative embodiment
of the voltage-modifying device 20 is shown. In this embodiment, the voltage-modifying
device 20 includes a low voltage module 90 (or a step-up circuit), such as a boost converter,
coupled in series with the EMI filtering device 60. Low voltage module 90 is configured to
increase a received voltage in response to the receiving a voltage that does not meet the
predetermined power supply requirement. For example, substation units may require 57 V-
120 V power supplies, which would make the substation units not compatible with a 120V-
277V meter.
A control circuit 92, within the low voltage module 90, regulates an input supply
voltage from the power supply 10 ( to deliver a voltage that is compatible with a
predetermined power supply requirement of the meter 30 (. The components within the
low voltage module 90 make up a boost converter that increases the voltage from the power
supply 10 ( to the predetermined power supply requirement of the meter 30 (.
As known to one of ordinary skill in the art, the boost converter includes two switches (a
switch 93 and a diode 94), an inductor 95, and a capacitor 96. The two switches 93, 94
alternate between charging the inductor 95 and discharging the inductor 95 to increase the
voltage. It is understood that other configurations of a boost converter, as known in the art,
may be used in low voltage module 90.
As seen in the low voltage module 90 may include other electrical circuit
components, such as an additional diode 97 and an additional capacitor 98. These may be
known as half-wave rectification elements. However, it is understood that the low voltage
module 90 may include any devices necessary to increase the voltage to the electric meter
(, in response to a voltage that does not meet the predetermined power supply
requirement.
Similar to the embodiment shown in at least one additional resistor 77 may
be provided for voltage feedback. For example, an additional resistor 77 is shown in to
provide voltage feedback of the first phase 102 to the meter 30 ( through the adapter
terminal 101. The additional resistor 77 also increases the voltage divider ratio of the voltage
feedback. This additional resistor 77 also provides a separate terminal 101 off of the first
phase 102 in order to provide supply separation. A second additional resistor 78 may also be
provided for voltage feedback and supply separation for the third phase 106. In this
embodiment, the second phase 104 does not pass through the EMI filtering device 60.
Turning now to a detailed schematic diagram of an alternative embodiment
of the voltage-modifying device 20 in is shown. In this embodiment, a third additional
resistor 79 is provided for the second phase 104. As with the first additional resistor 77 for the
first phase 102 and the second additional resistor 78 for the third phase 106, this third
additional resistor 79 provides voltage feedback and supply separation for the second phase
104. In this embodiment, the second phase 104 passes through the EMI filtering device 60.
Although not shown in the figures, it is understood that the voltage-modifying
device 20 may include a combination of the embodiment shown in FIGS. 4-5 and the
embodiment shown in FIGS. 6-7. That is, the voltage-modifying device 20 may include a
buck-boost converter or a sepic converter, which can increase or decrease the received voltage
to the predetermined power supply requirement of the meter 30.
The terminology used herein is for the purpose of describing particular
embodiments only and is not intended to be limiting of the invention. As used herein, the
singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the
context clearly indicates otherwise. It will be further understood that the terms "comprises"
and/or "comprising," when used in this specification, specify the presence of stated features,
integers, steps, operations, elements, and/or components, but do not preclude the presence or
addition of one or more other features, integers, steps, operations, elements, components,
and/or groups thereof.
This written description uses examples to disclose the invention, including the best
mode, and also to enable any person skilled in the art to practice the invention, including
making and using any devices or systems and performing any incorporated methods. The
patentable scope of the invention is defined by the claims, and may include other examples
that occur to those skilled in the art. Such other examples are intended to be within the scope
of the claims if they have structural elements that do not differ from the literal language of the
claims, or if they include equivalent structural elements with insubstantial differences from the
literal languages of the claims.
Where the terms “comprise”, “comprises”, “comprised” or “comprising” are used
in this specification (including the claims) they are to be interpreted as specifying the presence
of the stated features, integers, steps or components, but not precluding the presence of one or
more other features, integers, steps or components, or group thereto.
PARTS LIST
power supply
voltage-modifying device
electric meter
40 surge protection circuit
42 surge resistor
44 varistor
60 electromagnetic interference (EMI) filtering device
70 overvoltage protection module
71 diode
72 overvoltage detection circuit
73 varistor
74 diode
75 metal-oxide-semiconductor field-effect transistor (MOSFET)
76 capacitor
77 additional resistor
78 additional resistor
79 additional resistor
80 high voltage module
81 switches
82 buck control circuit
83 switch
84 inductor
85 capacitor
86 diode
87 additional capacitor
90 low voltage module
92 control circuit
93 switch
94 diode
95 inductor
96 capacitor
97 diode
98 capacitor
100 system
101 adapter terminal
102 first phase
104 second phase
106 third phase
107 neutral line
108 resistor
Claims (8)
1. A system for measuring electricity, comprising: an electric meter having a housing; and a voltage-modifying device connected to the electric meter for modifying a received voltage, such that the electric meter operates in accordance with a predetermined power supply requirement, wherein the voltage-modifying device is located within the electric meter housing or external to the electric meter housing; the electric meter further comprising an adapter terminal configured to connect to the voltage modifying device to provide voltage feedback for at least one received phase to the electric meter.
2. The system according to claim 1, wherein the electric meter includes an adapter terminal configured for separate connection of voltage feedback and power supply for the electric meter.
3. The system according to claim 2, wherein the voltage-modifying device includes an overvoltage transient protection module.
4. The system according to claim 3, wherein the overvoltage transient protection module includes a circuit that is configured to turn off power to the electric meter in response to the received voltage exceeding the predetermined power supply requirement.
5. The system according to claim 2, wherein the voltage-modifying device includes a high voltage, step-down module.
6. The system according to claim 5, wherein the high voltage, step-down module includes a circuit that is configured to decrease the received voltage in response to the received voltage exceeding the predetermined power supply requirement.
7. The system according to claim 2, wherein the voltage-modifying device includes a low voltage, step-up module.
8. The system according to claim 7, wherein the low voltage, step-up module includes a circuit that is configured to increase the received voltage in response to the received voltage not meeting the predetermined power supply requirement.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US13/210,499 US8837101B2 (en) | 2011-08-16 | 2011-08-16 | Voltage-modifying device for electric meter |
US13/210,499 | 2011-08-16 |
Publications (2)
Publication Number | Publication Date |
---|---|
NZ601721A NZ601721A (en) | 2014-02-28 |
NZ601721B true NZ601721B (en) | 2014-06-04 |
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