WO2000004392A1

WO2000004392A1 - An electrical supply measurement and management system

Info

Publication number: WO2000004392A1
Application number: PCT/AU1999/000584
Authority: WO
Inventors: Jonathan Paul Swain
Original assignee: Honeywell Ltd Canada
Current assignee: Honeywell Ltd Canada
Priority date: 1998-07-17
Filing date: 1999-07-19
Publication date: 2000-01-27
Anticipated expiration: 2001-01-17
Also published as: AUPP472498A0

Abstract

An electrical supply measurement and management system includes a plurality of power sensors (5). Each sensor (5) is clamped to a power line (4) leading to a consumer's premises (2). Communications transmission units (7) are associated, and in communication, with groups of the sensors (5). The system includes a number of communications reception units (8) in communication with the transmission units (7) via the power supply network. One reception unit is located at the supplier's premises and a reception unit (8) is located at each consumer's premises. The reception units (8) facilitate management of electrical power consumption. Each power sensor (5) measures a magnetic field around the line (4) to determine the current in the line (4) and, in so doing, to calculate power use.

Description

"An Electrical Supply Measurement and Management System"

Technical Field

This invention concerns an electrical supply measurement and management system. Such a system may be used to measure supply parameters and in addition to provide for remote and local management of energy.

Background Art

Electricity is distributed from large generating stations to individual consumer's premises over a network of electrical power supply lines. Where the power supply line enters a consumer's premises there is typically a meter box which contains circuit breakers and metering equipment. The metering equipment remains the property of the supplier, but the circuit breakers and downstream wiring are the property and responsibility of the consumer. The suppliers send staff to inspect the metering equipment at regular intervals to enable accounts to be prepared. There have been a number of proposals for the remote reading of the meters to reduce the inconvenience and expense of reading them.

Summary of the Invention

According to a first aspect of the invention, there is provided an electrical supply measurement and management system which includes: a plurality of electrical power sensors, each sensor, in use, being attached to an associated electric power supply line of a network of the electric power supply lines; communications transmission units associated with one or more of the sensors to interface data collected and to transmit that data over the network; at least one communications reception unit in communication with the transmission units for receiving transmitted data from the transmission units; and a display device associated with the, or each, reception unit for displaying information about a consumer's electrical supply.

Each sensor may be a solid state device having no moving parts. Each sensor may include a split housing having two parts which, when mated together, define a passage through which the power supply line passes, the split housing facilitating clamping of the sensor to the power supply line. Typically, the housing may be clamped about both the active and neutral lines. The use of sensors which clamp to the supply line facilitates the rapid redeployment of the sensors and reconfiguration of the system. In addition, the use of sensors which clamp on to the lines means that the sensors can be installed without rendering the supply line inactive. Each sensor may include a sensing means which measures current by sensing a magnetic field surrounding the power supply line. Hence, it will be appreciated that the sensors make non-invasive measurements of the electrical supply. In a preferred embodiment, use is made of a Hall effect device or a magneto-resistive device as the sensing means.

The sensing means may include a self-calibrating device. The self- calibrating device may comprise a closed loop feedback coil.

At least certain of the sensors may have communications transmission units incorporated therein, the transmission units being associated with a number of sensors. Instead, if desired, the transmission units may be arranged outside the sensors, for example, on power poles supporting the supply lines.

The transmission units may transmit over the network to the supplier, either between active and neutral lines of a phase, or between two phases of the supply. Communications to the consumer's premises may be between the active and neutral lines of the appropriate phase.

The system may include a plurality of communications reception units, one for location at a supplier's premises and the others for location at each consumer's premises.

Each reception unit may have a display device associated with it, each display device being incorporated in an electrical control unit, such as a personal computer, for enabling control of electrical equipment to be effected at those premises. The communications reception units at the consumer's premises may use conventional modems, and they may be connected to computers or other commonly available equipment to enable the display of data, such as the power used as a function of time, and the control of equipment. A concentrator will typically be used to make the information more manageable for the supplier. The concentrators may collect data locally and transmit it to the supplier over some other telecommunications link, such as the telephone network. The communications reception unit at the supplier's premises will be appropriate to the medium over which the data is transmitted. The supplier will usually be more interested in the power consumption of consumers, and information concerning power quality. Such a system may enjoy a number of advantages. For instance, it may enable consumers to monitor and regulate their power consumption. It may also enable the supplier to control the supply to equipment at the consumers' premises. This may avoid the requirement for a separate meter for off-peak supply and may facilitate a single meter with multiple tariffs. The system may enable remote recording of power consumption by the supplier and load switching and shedding. It may even replace conventional metering of electrical supply.

According to a second aspect of the invention, there is provided a method of measuring and managing an electrical supply which includes the steps of clamping a plurality of electrical power sensors to electric power supply lines of a network of the electric power supply lines to measure electric power; collecting data from the sensors and transmitting the data over the network; receiving transmitted data on at least one reception unit located at a supplier's premises; and displaying information about the supply on a display device associated with the, or each, reception unit. The method may include measuring the electrical power by sensing a magnetic field surrounding the supply line.

Further, the method may include receiving the transmitted data at the supplier's premises and each consumer's premises and displaying the data at such premises. According to a third aspect of the invention, there is provided a power sensor for measuring electric power in an electric power supply line, the sensor including a split housing having a pair of mating parts, the parts each defining a part of a passage such that, when the parts are brought into mating engagement, the housing is clamped about the supply line which passes through the passage; and a sensing means arranged in the parts of the housing such that, when the parts are in mating engagement, the sensing means surrounds the supply line for sensing current in the supply line.

The sensing means may sense a magnetic field about the supply line. The sensing means may include a laminate of elements of a high permeability material, the elements defining an air gap, and a sensing device arranged for measuring magnetic flux in the air gap.

According to a fourth aspect of the invention, there is provided a power sensor for measuring electric power in an electric power supply line, the sensor including a housing having a passage defined through it through which the supply line passes; and a sensing means arranged in the housing to surround the supply line, in use, to sense a magnetic field about the supply line, the sensing means including a laminate of elements of a high permeability material defining an air gap and a sensing device arranged for measuring magnetic flux in the air gap-

The sensor may include a feedback means arranged on the laminate for self-calibration purposes. The feedback means may be a closed loop feedback coil.

The laminate may be substantially C-shaped. The material from which the laminate is made may be a nickel-iron alloy.

The sensing device may be arranged in the air gap. The sensing device may be a Hall effect device or a magneto-resistive device.

Brief Description of the Drawings

An example of the invention will now be described with reference to the accompanying drawings, in which:

Figure 1 is a schematic diagram of part of an electrical supply measurement and management system, in accordance with one aspect of the invention;

Figure 2 is a schematic diagram of a larger part of the system of Figure l;

Figure 3 is a schematic diagram of a power sensor, in accordance with one embodiment of another aspect of the invention, used in the system of Figures 1 and 2, in an open configuration; Figure 4 is a schematic sectional end view of a power sensor, in accordance with a further embodiment of said other aspect of the invention;

Figure 5 is a schematic sectional end view of yet a further embodiment of the power sensor; and Figure 6 is a schematic sectional plan view of the power sensor of

Figure 5 taken along VI- VI in Figure 5.

Detailed Description of the Invention

An electrical supply measurement and management system, in accordance with one aspect of the invention, is used on a network of electrical power supply lines, indicated generally at 1, interconnecting a generating plant (not shown) with consumers' premises 2. The electrical power is typically supplied to a consumer's premises from a power pole 3 which supports some of the network lines 1. A particular pair of lines 4 extend from the power pole 3 to one consumer's premises 2. Clamped to the line 4 is an electrical power sensor 5, in accordance with another aspect of the invention and which will be described in greater detail below. A communications link extends from the sensor 5 to a communications transmission unit 7 also mounted on the power pole 3. One communications transmission unit 7 supports a number of premises 2.

A communications reception unit 8 is provided in the consumer's premises 2, and a communications reception unit (not shown) is also provided at the power supplier. Local transmission is by way of a powerline carrier signal 9. At the consumer's premises 2, the reception unit 8 is connected to a control centre, such as a personal computer(not shown), which allows the display of information related to the data received and which enables the processing and use of that information.

As shown in Figure 2, concentrators 10 are located at suitable points on the network, such as inside selected reception units 8, to compress the data for transmission to the supplier over the telephone network. Each concentrator 10 serves a series of local networks 11 within a coverage area 12. Each coverage area typically covers one electrical supply substation. At the supplier's premises the reception unit 8 provides more control of equipment. One embodiment of an electrical power sensor 5 is shown in greater detail in Figure 3. It comprises a housing defined by two semi-cylindrical parts 13 and 14 which are hingedly connected to each other so that they may be opened and closed. When closed, cylindrical channels 15.1 and 15.2 in parts 13 and 14, respectively, define a passage 15 which runs along the axis of the housing. The sensor 5 is mounted on at least the live conductor of the power line 4. The two semi-cylindrical halves are clamped together over the line to capture it in the passage 15 and to clamp the sensor 5 to the line 4. The electrical power sensor 5 is of solid state construction with no moving parts. It does not have any display and uses a sensing means 16 (described in greater detail below with reference to Figures 4 to 6) to measure the current flowing in the power line 4. It includes a link along which data is transmitted to one of the communications transmission units 7.

Instead of the communications transmission unit 7 being mounted on the pole 3, it could be incorporated in the housing of the sensor 5. It will be appreciated that it is not necessary for all of the sensors 5 of the system to include the transmission units 7.

The power supplier may locate the sensors 5 on the lines 4 it wishes to monitor by simply clamping them into place on those lines. There is no need to power down the lines before the sensors 5 are put into place. It will be appreciated that the use of power sensors 5 which are clamped to the lines 4 means that rapid redeployment of the sensors 5 is possible as is reconfiguration of the system with the minimum of downtime. The sensors 5 are used by the service provider to gather consumption information as well as load characteristics information.

Other embodiments of the sensors 5 are shown in Figures 4 to 6 of the drawings. With reference to Figure 3, like reference numerals refer to like parts unless otherwise specified.

In the embodiment illustrated in Figure 4, the housing of the sensor is clamped around both a live conductor 4.1 and a neutral conductor 4.2 of the line 4. The sensing means 16 includes a laminate 17 of a high permeability material which surrounds the live conductor 4.1 of the line 4. The laminate 17 is typically of a nickel-iron alloy. Each lamination of the laminate 17 is of three parts, a U-shaped part 18 which is received in the lid part 14 of the housing and two L-shaped parts 19, both of which are received in the base part 13 of the housing. When the two parts 13 and 14 of the housing are brought into mating engagement with each other, the laminate 17 thus surrounds the conductor 4.1 to measure the magnetic field about the conductor 4.1.

It is to be noted that aligned limbs of the two L-shaped parts 19 of the laminate 17 terminate short of each other to define an air gap 20. A sensing device 21, which may either be a Hall effect device or a magneto-resistive device, is located in the air gap 20. The sensing device 21 measures the magnetic flux in the air gap and, in so doing, calculates the power using a processor 22 arranged in the housing of the sensor 5. An optional circuit board 23 carrying the communications transmission unit 7 is shown in the housing of the sensor 5.

A closed loop feedback coil 24 is arranged about the aligned limbs of the L-shaped parts 19 of the laminate 17, the air gap 20 and the sensing device 21. The coil 24 is energised to partly nullify the flux in the laminate 17 and fulfils a self-calibrating function. Hence, errors in measuring the power are reduced.

In the embodiment in Figures 5 and 6, the sensor 5 is clamped around only the live conductor 4.1 of the power line 4. The construction of the sensing means 16 is the same as that described above with reference to Figure 4. The parts 13 and 14 of the housing of the sensor 5 are shown held together by bolts 25.

The sensors 5 provide information about the supply, such as current, voltage, power and reactance characteristics, to the communications transmission units 7 which transmit information on to the power lines 1. The communications transmission units 7 are able to communicate with other devices on the network such as the communication receiving units to ensure effective communications are established.

The consumer may use the information to determine its consumption, as well as the reactance characteristics of its loads. The system could be set up to automatically implement power saving measures such as turning appliances off when the consumption exceeds certain limits. For instance, when the kettle is turned on to boil water, the system may recognise it and turn off the refrigerator for a short time.

The provider may use the information to monitor the quality of the supply, including parameters such as voltage irregularities and frequency drift. The provider may also use the system to operate off-peak services and multiple tariffs without installing additional meters. Although the invention has been described with reference to a particular example, it should be appreciated that it may be exemplified in many other ways. Thus, the sensors may be secured to the line in other ways than the way described above. For example, the housing of the sensor may be a tubular, non-hinged element having a passage defined through it. Then, the sensor may be slid over the line 4 although this will necessitate powering down the line. The sensors may incorporate a display. In addition, a communications transmitter may be incorporated into each sensor if desired. The system may be applied in other situations than the aboveground cable network shown, and is equally applicable, for instance, to underground cable systems.

It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the invention as shown in the specific embodiments without departing from the spirit or scope of the invention as broadly described. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.

Claims

CLAIMS:

1. An electrical supply measurement and management system which includes: a plurality of electrical power sensors, each sensor, in use, being attached to an associated electric power supply line of a network of the electric power supply lines; communications transmission units associated with one or more of the sensors to interface data collected and to transmit that data over the network; at least one communications reception unit in communication with the transmission units for receiving transmitted data from the transmission units; and a display device associated with the, or each, reception unit for displaying information about a consumer's electrical supply.

2. The system as claimed in claim 1 in which each sensor is a solid state device having no moving parts.

3. The system as claimed in claim 1 or claim 2 in which each sensor includes a split housing having two parts which, when mated together, define a passage through which the power supply line passes, the split housing facilitating clamping of the sensor to the power supply line.

4. The system as claimed in any one of the preceding claims in which each sensor includes a sensing means which measures current by sensing a magnetic field surrounding the power supply line.

5. The system as claimed in claim 4 in which the sensing means includes a self-calibrating device.

6. The system as claimed in any one of the preceding claims in which at least certain of the sensors have communications transmission units incorporated therein, the transmission units being associated with a number of sensors.

7. The system as claimed in any one of the preceding claims which includes a plurality of communications reception units, one for location at a supplier's premises and the others for location at each consumer's premises.

8. The system as claimed in claim 7 in which each reception unit has a display device associated with it, each display device being incorporated in an electrical control unit for enabling control of electrical equipment to be effected.

9. A method of measuring and managing an electrical supply which includes the steps of clamping a plurality of electrical power sensors to electric power supply lines of a network of the electric power supply lines to measure electric power; collecting data from the sensors and transmitting the data over the network; receiving transmitted data on at least one reception unit located at a supplier's premises; and displaying information about the supply on a display device associated with the, or each, reception unit.

10. The method as claimed in claim 9 which includes measuring the electrical power by sensing a magnetic field surrounding the supply line.

11. The method as claimed in claim 9 or claim 10 which includes receiving the transmitted data at the supplier's premises and each consumer's premises and displaying the data at such premises.

12. A power sensor for measuring electric power in an electric power supply line, the sensor including a split housing having a pair of mating parts, the parts each defining a part of a passage such that, when the parts are brought into mating engagement, the housing is clamped about the supply line which passes through the passage; and a sensing means arranged in the parts of the housing such that, when the parts are in mating engagement, the sensing means surrounds the supply line for sensing current in the supply line.

13. The sensor as claimed in claim 12 in which the sensing means senses a magnetic field about the supply line.

14. The sensor as claimed in claim 13 in which the sensing means includes a laminate of elements of a high permeability material, the elements defining an air gap, and a sensing device arranged for measuring magnetic flux in the air gap.

15. A power sensor for measuring electric power in an electric power supply line, the sensor including a housing having a passage defined through it through which the supply line passes; and a sensing means arranged in the housing to surround the supply line, in use, to sense a magnetic field about the supply line, the sensing means including a laminate of elements of a high permeability material defining an air gap and a sensing device arranged for measuring magnetic flux in the air gap.

16. The sensor as claimed in claim 14 or claim 15 which includes a feedback means arranged on the laminate for self-calibration purposes.

17. The sensor as claimed in any one of claims 14 to 16 inclusive in which the laminate is substantially C-shaped.

18. The sensor as claimed in any one of claims 14 to 17 inclusive in which the sensing device is arranged in the air gap.