NZ617310B2 - Electrical measurement apparatus having a detector providing an identification signal and corresponding method - Google Patents
Electrical measurement apparatus having a detector providing an identification signal and corresponding method Download PDFInfo
- Publication number
- NZ617310B2 NZ617310B2 NZ617310A NZ61731012A NZ617310B2 NZ 617310 B2 NZ617310 B2 NZ 617310B2 NZ 617310 A NZ617310 A NZ 617310A NZ 61731012 A NZ61731012 A NZ 61731012A NZ 617310 B2 NZ617310 B2 NZ 617310B2
- Authority
- NZ
- New Zealand
- Prior art keywords
- detector
- meter
- signal
- identification signal
- electrical
- Prior art date
Links
- 238000005259 measurement Methods 0.000 title claims abstract description 26
- 230000000875 corresponding Effects 0.000 title 1
- 241000370685 Arge Species 0.000 description 10
- 230000005611 electricity Effects 0.000 description 3
- 238000009434 installation Methods 0.000 description 3
- 238000001514 detection method Methods 0.000 description 2
- 201000000194 ITM2B-related cerebral amyloid angiopathy 2 Diseases 0.000 description 1
- 230000001808 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 230000001419 dependent Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000000007 visual effect Effects 0.000 description 1
- 238000004804 winding Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G01D4/00—Tariff metering apparatus
- G01D4/002—Remote reading of utility meters
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R11/00—Electromechanical arrangements for measuring time integral of electric power or current, e.g. of consumption
- G01R11/02—Constructional details
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R11/00—Electromechanical arrangements for measuring time integral of electric power or current, e.g. of consumption
- G01R11/02—Constructional details
- G01R11/04—Housings; Supporting racks; Arrangements of terminals
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/0092—Arrangements for measuring currents or voltages or for indicating presence or sign thereof measuring current only
-
- 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
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B90/00—Enabling technologies or technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02B90/20—Smart grids as enabling technology in buildings sector
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y04—INFORMATION OR COMMUNICATION TECHNOLOGIES HAVING AN IMPACT ON OTHER TECHNOLOGY AREAS
- Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
- Y04S20/00—Management or operation of end-user stationary applications or the last stages of power distribution; Controlling, monitoring or operating thereof
- Y04S20/30—Smart metering, e.g. specially adapted for remote reading
Abstract
Disclosed is an electrical measurement apparatus for measuring an electrical parameter of a device. The apparatus is comprised of a meter and a detector, wherein the detector is arranged to detect the electrical parameter and transmit a measurement signal representing the electrical parameter to the meter. The detector is also arranged to provide to the meter an identification signal for identifying the detector to the meter. The identification signal is representative a measurable value of a component (Ri) of the detector, for example a resistance of a resistor. This signal may also be used to determine the rating of the detector, in particular the rating of a transformer or transducer of the detector, to ensure accurate readings are made by the meter and detector combination. e meter. The detector is also arranged to provide to the meter an identification signal for identifying the detector to the meter. The identification signal is representative a measurable value of a component (Ri) of the detector, for example a resistance of a resistor. This signal may also be used to determine the rating of the detector, in particular the rating of a transformer or transducer of the detector, to ensure accurate readings are made by the meter and detector combination.
Description
ELECTRICAL MEASUREMENT APPARATUS AND METHOD
Field of the Invention
The present invention relates to an electrical measurement
apparatus for measuring an electrical parameter of a
device; a detector for use in the measurement of an
electrical parameter of a device; and a method of measuring
an electrical parameter of a device. For example the
invention relates to an electrical measurement apparatus
and method, and is concerned particularly with an
electrical measurement apparatus and method suitable for
use in an electrical metering system.
Background of the Invention
In commercial premises particularly, the electricity usage
of several devices or appliances, hereinafter referred to
generally as loads , is often monitored using separate
meters for each load. In such cases, in order to derive
valuable data about the energy usage of each load it is
necessary to collate metered values manually, and
subsequently enter the data manually on a computer for
processing.
A previously considered example of electricity meter brings
together a fixed number of metering units and combines them
in a unitary housing, together with a common visual display
and processing means to manipulate and present the data
collected by the individual metering units. Signal wires
are used to carry the measurement signals from current
detectors such as current transducers or transformers
located locally at each load. The combined multi-meter load
is particularly suited to modern premises in which the
electrical supply enters the building at a single location,
and is controlled from a single control panel.
Modern electronic electricity meters are designed to
measure a variety of load types and sizes.
Current inputs to the meters are standardised to accept a
specific signal type and value which represents a larger
measured value of current at the load. A range of external
current transformers or transducers are used to convert the
detected primary current into a representative
secondary signal that may be measured by the metering
circuit.
For example a meter may accept a 0.333 Vac signal which
represents any nominal primary current determined by the
selection of an appropriate external current transducer.
Typical external transducers may be of a split or toroidal
type such as 100 Amp/0.333V or 500 Amp/0.333V.
When a metering system is installed the user must select
the most appropriate transformers/transducers for the
measured load dependent on the maximum current that the
load would draw in normal operation. These devices may be
physically located some distance away from the meters
themselves. For example the transformers/transducers may be
located in a separate switch enclosure or in a different
room. Many meters may be installed together and may be
connected to different ranges of transformers/transducers.
During commissioning of the metering system the installing
engineer must program the individual meters to provide
readings that are scaled in proportion to the specific
transformers or transducers to which they are respectively
connected. This often presents the practical problem of
identifying which set of wires is associated with which
remotely located transducer/transformer.
To assist with this the installing engineer carefully
labels the wires with the load size and type before
installing the transformers/transducers. If this stage is
forgotten or performed inaccurately it may be necessary to
remove the installation and start again.
If mistakes are made during installation or commissioning
these may remain undetected for long periods, and indeed
may never be picked up. However, such mistakes can be
costly. For example if a 200 Amp transducer is connected to
a meter which is programmed to scale for a 150 Amp
transducer, when 200 Amps is detected by the transducer the
secondary signal will provide 0.333 V to the meter. The
meter is scaled to assume that 0.333 V is equivalent to 150
Amps so will display readings which are in error by the
ratio 150/200 (i. e. a 25% error). This discrepancy may not
be obvious to the meter reader, and the power/energy
readings accepted may lead to errors in billing and
possibly the taking of inappropriate management decisions
based on the erroneous data. Larger errors in scaling may
be less likely to escape detection.
US 2008/0284614 describes a power monitoring system for
monitoring characteristics of power transmitted through one
or more power lines, comprising a meter base and multiple
option modules. The meter base includes a processor and
associated circuitry for processing signals derived from
sensors coupled to said power lines and producing output
signals representing selected characteristics of the power
transmitted through the power lines, and a housing
containing the processor and the associated circuitry and
having a first surface adapted to be mounted on a DIN rail,
and a second surface containing multiple connectors for
receiving multiple modules and electrically connecting the
modules to the processor and the associated circuitry.
US 4,963,820 describes an energy meter composed of a meter
chassis having a transducer connected to sense energy usage
and to provide an output having a fixed relation to the
sensed energy usage, a replaceable register connectable to
the transducer for converting the output provided by the
transducer into a readable energy usage indication, a
transducer identifying unit secured to the chassis and
coded to identify the fixed relation between the transducer
output and the sensed energy usage, and a transducer
sensing unit secured to the register for coupling with the
transducer identifying unit when the register is connected
to the transducer.
JP 2005 038492 describes an identification method for
mounting parts of electronic device, and an electronic
device which can identify mounting parts, comprising an
identification resistor having different resistance values
for each version information of a circuit board internally
connected between the first pin and the third pin which are
empty terminals on equipment function of an interface
section of the FDD drive. An identification circuit
including the resistor is formed by a tester through the
first pin and the third pin. The resistor is identified
based on the output result from the identification circuit,
and based on the identification result, version information
of a circuit board is specified and the circuit board is
identified.
It is generally desirable to overcome or ameliorate one or
more of the above described difficulties, or to at least
provide a useful alternative.
Summary of the Invention
According to the present invention there is provided
electrical measurement apparatus for measuring an
electrical parameter of a device, the apparatus comprising
a meter and a detector, wherein the detector is arranged to
detect the electrical parameter transmit a measurement
signal to the meter, which signal is representative of the
detected electrical parameter, and wherein the detector is
arranged to provide to the meter an identification signal
for identifying the detector to the meter, and
characterised in that the detector comprises a component
(Ri) having a measurable value, which measurable value
serves as the identification signal.
According to the present invention, there is also provided
a detector for use in the measurement of an electrical
parameter of a device, wherein the detector is arranged to
detect the electrical parameter and transmit a measurement
signal to a meter, which signal is representative of the
detected electrical parameter, wherein the detector is
arranged to provide to a meter an identification signal for
identifying the detector to the meter, and characterised in
that the detector comprises a component (Ri) having a
measurable value, which measurable value serves as the
identification signal.
According to the present invention, there is also provided
a method of measuring an electrical parameter of a device,
the method comprising detecting the electrical parameter
using a detector, and transmitting a measurement signal to
a meter, which signal is representative of the detected
electrical parameter, the method further comprising
providing to the meter an identification signal for
identifying the detector to the meter, and characterised in
that the detector comprises a component ( Ri) having a
measurable value, which measurable value serves as the
identification signal.
Preferred embodiments of the present invention aim to
address at least some of the aforementioned shortcomings in
the prior systems.
In a preferred arrangement the identification signal may be
derived from a component in the detector or in an
electrical connection between the detector and the meter,
or a component associated with either.
The identification signal may be derived from the presence
and/or value of the component. Preferably the detector
comprises a component having a measurable value, which
measurable value serves as the identification signal.
The detector may be arranged to communicate with the meter
wirelessly. Alternatively, or in addition, the detector may
be connected to the meter by wire. In a preferred
arrangement the detector comprises a resistive element, the
value of which is measured by the meter to determine the
identity of the detector.
The meter may comprise identification means, which
preferably comprises a circuit, which is arranged in use to
receive the identification signal and to use it to identify
the detector.
The detector may be according to any statement herein.
The electrical parameter to be measured may comprise
electrical current and/or power.
The method may comprise identifying the detector by
detection and/or measurement of a component in or
associated with the detector, the presence and/or value of
which component serves to identify the detector.
Brief Description of the Drawings
Preferred embodiments of the present invention are
hereafter described, by way of non-limiting example only,
with reference to the accompanying drawings, in which:
Figure 1 shows schematically a detector, in the form of a
current transducer, for use in apparatus; and
Figure 2 is a schematic circuit diagram of the current
transducer of Figure 1.
Detailed Description of Preferred Embodiments of the
Invention
Turning to Figure 1, there is shown, generally at 10, a
three - phase toroidal current transducer comprising a
cuboid detector body 12, having three cylindrical passages
14 each for receiving a single phase cable of a three
phase load (not shown). Each of the three passages 14 has
an embedded toroidal winding (not shown) which is used to
detect a current in the load cable (also not shown).
Signals representing the current in each of the three
individual load cables are sent to a meter (not shown),
which may be located remotely. The signals are transmitted
along a multi-core signal cable 16, which has a standard
connector 18 for a plug-in connection to the meter.
As will be described below, one of the wires in the multi-
core signal cable 16 is connected to a component in the
transducer 10 that identifies the rating of the transducer,
so that the meter can determine this automatically when the
signal cable is plugged in.
Figure 2 shows the circuit of the transducer 10. The three
currents in the three single phase load cables are
represented by I1, I2 and I3, and the three toroidal
windings are represented by T1, T2 and T3. In each case a
burden resistor, respectively Rb1, Rb2 and Rb3 is connected
between ground and a signal line to produce voltage signals
V1, V2 and V3 for supply via cable 16 to the meter. Other
wires in the cable 16 include a ground connection V0 and a
connection to an identification resistor Ri, itself
connected to ground.
The value of the identification resistor Ri can be
determined by a resistor detector circuit in the
processor in the meter, and this is used to set the rating
of the transducer 10 which the meter uses when calculating
the current in the load cables. For example, the meter may
be programmed to determine that an identification resistor
having a value of 2 k means that the transducer is rated
at 100A/0.333V, which means that if a voltage of 0.333V is
measured at any of Vi1, Vi2 or Vi3 this represents a
current of 100A in the respective load cable.
Of course the identification component need not be a
resistor. With appropriate circuitry the meter could
determine the rating of the transducer by detecting the
value of a different type of component. However a resistor
provides a particularly inexpensive solution.
Furthermore the current detector need not be a transducer,
but could for example be a transformer. In such a case the
circuit would be different as there would be two voltage
identification lines for each of the single phase
currents. Again a simple resistor could be used as the
identification component.
The example given above is of a three phase load
measurement, but the invention is equally applicable to a
single phase load, which would require the use of fewer
wires in the cable 16.
During a powering up of the meter the resistor detector
circuit in the meter determines the value of the resistor
and automatically configures the meter scaling and
calibration to suit the transducer connected, without error
or ambiguity to save time during commissioning.
The standard connector 18 is easily plugged into the meter,
which also saves time during installation and commissioning
of the meter system.
Embodiments of the invention aim to add a low cost
component to the transducer or set of transducers which is
detected by an additional measurement circuit in the meter.
A resistor is sufficient for this purpose, and adds
negligible cost to the transducer. Resistor values can be
accurately measured by the meter to determine which
transducer is fitted at the end of the secondary wires.
The accuracy of the resistor detector could be sufficient
as to differentiate between many primary scaling factors
and, if required, transducer types. An example of how this
could work is laid out in the table shown below:
Resistor CT Primary Assumed CT Type Assumed
1k Type A (S mall Split CT)
1.2k Type B (M edium Slit CT)
1.3k 50 Amp Type C ( L arge Split CT)
1.4k Type D ( S mall Ring CT)
1.5k Type E (L arge Ring CT)
2k Type A (S mall Split CT)
2.2k Type B (M edium Slit CT)
2.3k 100 Amp Type C (L arge Split CT)
2.4k Type D (S mall Ring CT)
2.5k Type E (L arge Ring CT)
2k Type A ( S mall Split CT)
3.2k Type B ( M edium Slit CT)
3.3k 150 Amp Type C (L arge Split CT)
3.4k Type D (S mall Ring CT)
3.5k Type E ( L arge Ring CT)
4k 200 Amp Type A ( S mall Split CT)
4.2k Type B ( M edium Slit CT)
4.3k Type C (L arge Split CT)
4.4k Type D (S mall Ring CT)
4.5k Type E ( L arge Ring CT)
5k Type A (S mall Split CT)
.2k Type B ( M edium Slit CT)
.3k 300 Amp Type C (L arge Split CT)
.4k Type D (S mall Ring CT)
.5k Type E (L arge Ring CT)
Whilst endeavouring in the foregoing specification to draw
attention to those features of the invention believed to be
of particular importance, it should be understood that the
applicant claims protection in respect of any patentable
feature or combination of features referred to herein,
and/or shown in the drawings, whether or not particular
emphasis has been placed thereon.
Throughout this specification and the claims which follow,
unless the context requires otherwise, the word comprise,
and variations such as comprises and comprising, will
be understood to imply the inclusion of a stated integer or
step or group of integers or steps but not the exclusion of
any other integer or step or group of integers or steps.
The reference in this specification to any prior
publication (or information derived from it), or to any
matter which is known, is not, and should not be taken as
an acknowledgment or admission or any form of suggestion
that that prior publication (or information derived from
it) or known matter forms part of the common general
knowledge in the field of endeavour to which this
specification relates.
Claims (7)
1. Electrical measurement apparatus for measuring an electrical parameter of a device, the apparatus comprising 5 a meter and a detector, wherein the detector is arranged to detect the electrical parameter and transmit a measurement signal to the meter, which signal is representative of the detected electrical parameter, wherein the detector is arranged to provide to the meter an identification signal 10 for identifying the detector to the meter, and characterised in that the detector comprises a component (Ri) having a measurable value, which measurable value serves as the identification signal. 15
2. Electrical measurement apparatus according to claim 1, wherein the detector is arranged to communicate with the meter wirelessly.
3. Electrical measurement apparatus according to claim 1 20 or 2, wherein the detector may be connected to the meter by wire.
4. Electrical measurement apparatus according to any of the preceding claims, wherein the detector comprises a 25 resistive element, the value of which is measured by the meter to determine the identity of the detector.
5. Electrical measurement apparatus according to any of the preceding claims, wherein the meter comprises 30 identification means, which comprises a circuit arranged in use to receive the identification signal and to use it to identify the detector.
6. A detector for use in the measurement of an electrical parameter of a device, wherein the detector is arranged to detect the electrical parameter and transmit a 5 measurement signal to a meter, which signal is representative of the detected electrical parameter, wherein the detector is arranged to provide to a meter an identification signal for identifying the detector to the meter, and characterised in that the detector comprises a 10 component (Ri) having a measurable value, which measurable value serves as the identification signal.
7. A method of measuring an electrical parameter of a device, the method comprising detecting the electrical 15 parameter using a detector, and transmitting a measurement signal to a meter, which signal is representative of the detected electrical parameter, the method further comprising providing to the meter an identification signal for identifying the detector to the meter, and 20 characterised in that the detector comprises a component (Ri) having a measurable value, which measurable value serves as the identification signal.
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB1106993.7 | 2011-04-27 | ||
GB1106993.7A GB2493688B (en) | 2011-04-27 | 2011-04-27 | Electrical measurement apparatus and method |
PCT/GB2012/050914 WO2012146924A1 (en) | 2011-04-27 | 2012-04-26 | Electrical measurement apparatus having a detector providing an identification signal and corresponding method |
Publications (2)
Publication Number | Publication Date |
---|---|
NZ617310A NZ617310A (en) | 2015-09-25 |
NZ617310B2 true NZ617310B2 (en) | 2016-01-06 |
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