WO2002091543A2

WO2002091543A2 - A system for electric energy distribution

Info

Publication number: WO2002091543A2
Application number: PCT/IB2002/001623
Authority: WO
Inventors: Tor-Ole Bang-Steinsvik; Bernt Hansen; Morten Hellum; Oskar Arne Henriksen; Jens Petter Roenning; Geir Svoen; Jan Teigland
Original assignee: Abb As
Priority date: 2001-05-08
Filing date: 2002-05-08
Publication date: 2002-11-14
Also published as: NO20034963D0; WO2002091543A3; SE522224C2; NO329517B1; SE0101589D0; AU2002258056A1; EP1391022A2

Abstract

The invention generally relates to energy metering for billing purposes, low voltage cable protection against by-pass coupling and communication possibilities for collecting energy meter values. More particularly, the invention relates to a system for electric energy distribution and for remote electricity metering, comprising a low voltage distribution grid having at least one splitting site, wherein at least one splitting site has a distribution unit. The distribution unit comprises connection means (18) and energy metering means (20) for each consumer site and a data communication unit (24) arranged to receive metering values from said energy means (20) and transmits the collected metering values from said distribution unit (14).

Description

A system for electric energy distribution

TECHNICAL FIELD

The invention relates generally to energy metering for billing purposes, low voltage cable protection against by-pass coupling and comrnunication possibilities for collecting energy meter values. More particularly, the invention relates to a system for electric energy distribution and for remote electricity metering, a distribution unit and a connector device located in a splitting site of such an electric energy distribution system.

BACKGROUND OF THE INVENTION

Electricity metering in a common S3?"stem for electric energy distribution to different customer/ consumer sites is solved by having a watt-hour meter at each site. The consumption at each site during a period is either registered by the customer who reports the metering value to the utility company or registered by a person visiting each site and watt-hour meter. Both approaches have their drawbacks.

For eliirilnating the costs of having persons visiting each watt-hour meter, different remote electricity consumption acquisition are known.

From EP 0 248 137, Bl , a system is earlier known, which accumulates verifiable energy demand data from a remote electricity meter. Said system comprises means for detecting and counting pulses generated by the remote electricity meter, which are indicative of energy consumption at the customer site during successive time intervals. The pulse count during intervals is stored in a solid state memory means. A predetermined number of successive time intervals constitute a record. The output of the solid state memory can be transmitted optically over an optical link or electrically to a portable storage device or directly over a telephone line to a central computer. The system preferably comprises microprocessor based circuitry contained either in the electricity meter or in a separate housing. The electricity meter is located at the customer site and the customer has full access to the electricity meter and the cable in front of the meter.

From DE 36 15 402, Al , another system for remote electricity metering is earlier known, which system comprises a data centre and several encoding electricity meters. Each encoding electricity meter is an assembly of one encoder and several electricity meters. In the encoder the readings of each electricity meter are encoded, stored at fixed intervals and acquired by the data centre at predetermined time points. The electricity meters don't have any counting means by themselves. The encoder and electricity meters are assembled as sealed slide-in modules into a rack or stand. The encoder is connected to each electricity meters with a sealable conductor. The encoder has one or more meter value displays, but it is connected over a separate data bus to a personal computer and a writing/ printing device for billing purposes.

However, these known systems have some drawbacks. One drawback with those systems using a telephone line as a medium for transmitting metering values is that the telephone line can be in use for other purposes when the transmission of consumption data is to be transmitted to the central computer. A separate data bus have the advantage of making the transmission of data and instructions independent of other traffic over the cable, but it is economically advantageous to use a pre-existing communication link, especially over long distances. It is earlier known power cables containing separate data transmission sub-cables or conductors for allowing transmission over power cables. At least one separate conductor, data bus or transmission link is incorporated in the power cable. The bus or link can be a wire for electrical transmission or a fibre for optical transmission of data or information over the cable. However, the cable without a separate information channel has to be changed to a cable including such a transmission medium. Such an operation can be expensive, and unnecessary, if the cable is still in good condition.

If the electricity is expensive, some consumers may find it profitable to connect a cable in front of the electricity meter. Such a "by-pass- cabling" will lead electric current at the side of the electricity meter and the consumer will have free electricity. In some markets, the energy utilities have big problems with energy thefts and lost receipts.

BRIEF DESCRIPTION OF THE INVENTION One purpose of the present invention is to provide a system for electric energy distribution wherein said problems and drawbacks are eliminated.

This purpose is achieved according to the present invention by arranging together, inside a distribution unit, a connection means and an energy metering means for each consumer site. Further, a data corrirnunication unit can be arranged, inside or outside said distribution unit, for transmitting collected metering value from said distribution unit.

In more detail, the present invention relates to a system for electric energy distribution to at least one consumer site and for remote electricity metering, comprising at least one low voltage distribution grid having at least one splitting site, wherein at least one splitting site has a distribution unit for distributing electric energy to a number of consumer sites connected to said splitting site. The present invention provides a system wherein said distribution unit comprises connection means and energy metering means for each consumer site and a data communication unit arranged to receive metering values from said metering means and transmit collected metering values from said distribution unit.

In another aspect of the invention, it is also provided a distribution unit for electric energy distribution to at least one consumer site, said distribution unit comprises connection means for connecting each consumer site to a low voltage distribution cable of a low voltage distribution grid. Said distribution unit also comprises an energy metering means for deterrriining a metering value of the energy consumption of each consumer site and a data communication unit arranged to transmit collected metering values from the distribution unit.

In further one aspect of the invention, it is also provided a connector device located in a splitting site of an electric energy distribution system. Said device comprises a connector means for connecting a consumer site to said system and it also comprises an electricity metering means for metering the energy consumption of said consumer site.

One advantage of the present invention is that the energy utility has 100% system control. The utilities do not need to interact with for example "Smart house Application Service Providers (ASP)" or any other service suppliers or operator. Another advantage of the present invention is that the energy utility can perform installation, maintenance and repair and meter reading completely independent of the customer, since no part of the installation is located in the consumer site.

Further one advantage of the present invention is that the system protects against energy theft.

BRIEF DESCRIPTION OF THE DRAWINGS

The characteristics and advantages of the invention will become clearer from the detailed description of some preferred embodiments thereof illustrated in the appended drawings.

Figure 1 is a partial block diagram of a system for low voltage distribution according to the present invention.

Figure 2 is a perspective view of a distribution unit in a system according to the present invention.

Figure 3 is a perspective view of a connector device according to another aspect of the present invention.

Figure 4 is a perspective view of a separate energy metering means module.

DETAILED DESCRIPTION OF THE INVENTION In figure 1 , a part of a system 10 for electric energy distribution to a number of consumer sites and for remote electricity metering is illustrated. Said system 10 comprises at least one low voltage distribution grid 12 having at least one splitting site. Each splitting site has a distribution unit 1 for distributing electric energy to each consumer site 16 connected to said splitting site. The distribution unit 14 comprises connection means 18 and energy metering means 20 for each consumer site 16 and a data cornmunication unit 24 arranged to transmit collected electricity metering values of the different consumers over a low voltage distribution cable 11 of said grid 12 to a consumption data collector 26.

The data cornmunication unit 24 will be described in more detail further down when the distribution unit 14 in figure 2 is described. The connection means 18 and energy metering means 20 for each consumer site will be described in connection to figure 3 and 4, respectively.

Said low voltage distribution cable 11 contains separate power sub- cables or conductors. It is not necessary that the cable comprises at least one separate conductor, data bus or transmission link for allowing transmission over the power cable. The bus or link can be a wire for electrical transmission or a fibre for optical transmission of data or information over the cable.

The invention can be of the "plug and play" type. A cable without a separate information channel has not to be changed to a cable including such a transmission medium, if the distribution unit is changed to a distribution unit 14 according to the invention. Thus, it's only to exchange distribution units without changing cables.

The consumption data collector 26 is in this embodiment situated in connection to a secondary substation 28. The consumption data collector 26 is connected to the low voltage distribution cable 1 1 by means of buffer circuits for eliminating high voltage break-through, transients and noise. A last transformer 30 before the consumer sites 16 is often situated in a secondary substation 28. However, the consumption data collector 26 can be located anywhere in a low volt distribution grid 12 between the splitting sites and the last transformer 30 that is transforming medium voltage (10-20 kV) into low voltage (< 1 kV). The consumption data collector 26 communicates with a central data processing unit 32 having a data processing unit (DPU) that it is used for administrative and accounting purposes. The transferred data is stored in some kind of data base handled by the central data processing unit 32.

For an example, the consumers do not need to have separate electricity meter of the kWh type in their sites. The utility company provides a home page on the Internet ("world wide web") and each consumer may by means of a unique password of their own visit and check their consumption. The password will secure privacy.

In this embodiment, data and instructions are transmitted over a radio link 34 between a radio transceiver 36 of the consumption data collector 26 and one radio transceiver 38 of the central data processing unit 32. The transceivers may use any suitable protocol, such as e.g. a mobile communication system protocol like GSM, NMT, UMTS, DAMPS, AMPS, PCS, Bluetooth etc.

In other embodiments, another medium than a radio link 34 may be used for transmitting data and instructions between the consumption data collector 26 and the central data processing unit 32. For an example, a fibre optic system can be used for the above-mentioned purpose.

In further one embodiment, said collected metering values are transmitted from the distribution unit over a radio link to a consumption data collector (26) or directly to the central data processing unit 32. The data and instructions are transmitted over a radio link from a radio transceiver connected to the data communication unit 24 and a radio base station of a PLMN (Public Land Mobile Network) of any available radio standard. The transceiver may use any suitable protocol, such as e.g. a mobile communication system protocol like GSM, NMT, UMTS, DAMPS, AMPS, PCS, Bluetooth etc. The data and instructions can either be forwarded via the PLMN or other PLMNs or other networks, like PSTN (Public Switched Telephony Network), ISDN (Integrated Services Digital Network) and Public Data Networks, to the central data processing unit 32.

In another embodiment, said collected metering values are transmitted from the distribution unit (14) over an optical fibre to the central data processing unit 32.

A distribution unit 14 at a splitting site of a system according to a preferred embodiment of the present invention is a cable distribution cabinet, CDC. Such a cabinet 50 is illustrated in figure 2. The cabinet 50 is a strong metal casing having a door (not shown) and it is locked for protecting against non-authorised handling of the devices inside the cabinet 50. Owners of the consumer sites will not have access to the cabinet 50. It has an assembly plate 52 mounted inside, on which different apparatuses may be mounted for connection with the different phase and earth conductors. Inside said cabinet 50, a number of connector devices 22 are arranged for tapping electric energy from the conductors (not shown) to each of the consumer sites 16 connected to said cabinet 50. A connector device 22 according to the present invention comprises a connection means 18 and an energy metering means 20. The electricity metering means 20 are connected to a communication unit 24. The unit 24 collects the metering values of all electric metering means 20 for transmitting the values over the low voltage distribution cable of the grid 12 back to a consumption data collector 26. In one preferred embodiment the data collector 26 is located in a secondary substation 28, which transforms medium voltage to low voltage. The cornrnunication unit 24 may produce a distribution line carrier signal (DLC) on which the metering data is modulated in any known manner. Said unit 24 may be a transceiver for receiving instructions or data via the low voltage cable of the grid 12 or only a transmitter that transmits data in predetenrnined intervals.

The data communication unit 24 can comprise a metering data collector, a conventional DLC-type (Distribution Line Carrier) corτimunication modem, means having additional computing capability, a power transformer and a casing. The casing enclosing the cornrnunication unit 24 is water-resistant and allows the data communication unit 24 to be fitted onto standard busbars used in distribution units/CDCs and other conventional splitting sites. The casing may be designed for not taking more space than a standard connector of the FSD-type. Integrated busbar contacts allow connection directly to the busbars. The unit 24 draws its power directly from the busbars via the busbar contact and is thus self- supplied. The data communication 24 unit can be mounted into already installed distribution units/CDCs in the field where the only requirement is an empty slot on the busbar system. The unit 24 does also have connectors for the incoming, registered energy consumption from each metering means 20. The data communication unit 24 collects the kWh-readings of each metering means 20 and transmits the data either onto the low-voltage distribution net via DLC- communication (Distribution Line Carrier) or via the air interface by use of radio cornrnunication equipment. The interface between the energy metering means 20 and the cornrnunication unit 24 can either be SO pulses, a "register dump" from energy metering means 20, or a more sophisticated communication protocol. According to standards (e.g. DIN 43 864), SO pulses should only be sent over very short distances, less than 0.5 m. This puts quite strong restrictions to the layout of a distribution unit/ CDC.

Transfer of register data between energy metering means 20 and the communication unit 24 can be done either with separate wires 13 (see figure 1), or via some sort of serial interface 15.

One solution is a serial interface bus. For the "serial point to multipoint" bus cornmunication. there are several options. One solution is to use the standard IEC 1107 protocol. The advantage of choosing IEC 1107 is that this is a standard protocol for communication with electricity meters.

Another solution is to use a suitable serial interface protocol. This can be a simple protocol with minimum overhead, optimised for register reading. It can be similar to a register dump function.

It is not necessary to arrange the data cornrnunication unit 24 inside the distribution unit/CDC 14. It is possible to put the data communication unit outside the distribution unit/ CDC and such an arrangement will still be within the scope of protection of the claims and the inventive idea.

In figure 3, a preferred embodiment of said connector device 22 is illustrated. A connection means 18 is arranged together with an energy metering means 20 for establishing a connector device 22. Said connection means 18 may have different design and additional functions beyond the connecting function. It is of the fuse switch disconnector type. The fuse switch disconnector provides the low voltage cable protection. A manual switch is integrated in this connection means, however, it is also possible to use a fuse switch disconnector without a manual switch. Two embodiments of the invented connector device are suggested. A first embodiment comprising a separate connector device 22 having means (not shown) for connecting a separate energy metering means 20 (as illustrated in figures 3 and 4). The energy metering means 20 will than be mounted on to the connector device 22 by means of said means for connecting an energy metering means 20.

In a second embodiment of the invented connector 22 the energy metering means is integrated together with the connector means within the same casing.

In figure 4. a separate energy metering means 20 is shown (the front side 48 directed upwards). Said energy metering means 20 comprises a circuit for energy metering and a casing 46. The casing 46 is so constructed that it takes rninirnal space, allows adequate cable connection and can be fastened directly to a standard connector 22, for an example of the FSD-type (Fuse-Switch-Disconnector). The metering means 20 is equipped with three incoming flexible cables or pins 40, 42, 44 that are prepared to fit easily into the staggered standard means for connecting, e.g. socket holes or clamps, on the connector. On the outgoing side, three cage clamps are arranged in such a manner that they can be accessed by screwdriver from the front. The cage clamps are dimensioned to take the standard Cu or Al cables that are corrimonly used between CDCs and private consumers.

A circuit for energy metering means 20 can be a conventional, electronic shunt-type kWh-meter, for alternatively 1 -phase or 3- phase measurement, having a shunt resistor operating as a current resistor. It is enclosed in a water resistant casing 46 that allows the meter to be fitted onto the conventional tier type fuse-switch- disconnectors (FSDs) that are used in cable distribution cabinets (CDCs) and other conventional splitting sites. The metering device will thus fit into the many thousand CDCs that already are installed worldwide.

The metering values relate from customer sites having either srngle- phase or 3-phase connection to the splitting site. Customer sites of both kinds of connection can share one distribution unit/CDC. Both 3-phase/3 wire and 3 phase/4 wire connections are considered. As an example, up to 24 single phase measurements must be done in a distribution unit containing 8 connectors. Hence, the data collector must be programmable for different configurations, in order to map each single-phase reading on to the correct customer.

The present invention is not limited to the above-described preferred embodiments. Various alternatives, modifications and equivalents may be used. Therefore, the above embodiments should not be taken as limiting the scope of the invention, which is defined by the appended claims.

Claims

PATENT CLAIMS

1. A system (10) for electric energy distribution to at least one consumer site (16) and for remote electricity metering, comprising at least one low voltage distribution grid (12) having at least one splitting site, wherein at least one splitting site has a distribution unit (14) for distributing electric energy to each consumer site connected to said splitting site, characterised in that, said distribution unit (14) comprises connection means (18) and energy metering means (20) for each consumer site (16) and a data communication unit (24) arranged to receive metering values from said energy metering means (20) and transmits the collected metering values from said distributing unit (14).

2. A system according to claim 1, characterised in that, said connection means (18) and energy metering means (20) are arranged together establishing a connector device (22).

3. A system according to claim 1 or 2, characterised in that, said collected metering values are transmitted over said grid (12) to a consumption data collector (26).

4. A system according to claim 3, characterised in that, said collected metering values are transmitted over said grid (12) to a consumption data collector (26) that is located in a secondary substation (28), which transforms medium voltage to low voltage.

5. A system according to claim 4, characterised in that, the collected metering values is transmitted from the consumption data collector (26) via a radio link (34) to a utility company or service provider.

6. A system according to claim 1 or 2, characterised in that, said collected metering values are transmitted from the distribution unit (14) over a radio link.

7. A system according to claim 1 or 2, characterised in that, said collected metering values are transmitted from the distribution unit (14) over an optical fibre.

8. A system according to any previous claim, characterised in that, said connection means (18) is of the fuse switch disconnector type.

9. A system according to any previous claim, characterised in that, owners of the consumer sites can check their consumption on the Internet ("world wide web").

10. A connector device (22) located in a splitting site of an electric energy distribution system (10), said device (22) comprises a connector means (18) for connecting a consumer site (16) to said system (10), characterised in that, said device (22) also comprises electricity metering means (20) for metering the energy consumption of said consumer site (16).

11. A connector device (22) according to claim 10, characterised in that, said electricity metering means (20) is connected to a communication unit (24) that collects the metering value of said electric metering means (20) and transmits said value from said splitting site.

12. A connector device (22) according to claim 10, characterised in that, said device (22) is arranged and mounted in a cable distribution cabinet (50) located at the splitting site.

13. A connector device (22) according to claim 12, characterised in that, inside said cabinet (50) the device (22) is mounted on to a common assembly plate (52) for arranging other connector devices (22) close together.

14. A distribution unit (14) for electric energy distribution to at least one consumer site (16), said distribution unit (14) comprises connection means (18) for connecting each consumer site (16) to a low voltage distribution cable (11) of a low voltage distribution grid (12), characterised in that, said distribution unit (14) also comprises an energy metering means (20) for determining a metering value of the energy consumption of each consumer site (16) and a data communication unit (24) arranged to transmit collected metering values from said distribution unit (14).

15. A distribution unit (14) according to claim 14, characterised in that, said connection means (18) and energy metering means (20) are arranged together establishing a connector device (22).

16. A distribution unit (14) according to claim 14 or 15, characterised in that, the data communication unit (24) comprises a metering data collector and a conventional DLC -type (Distribution Line Carrier) communication modem.

17. A distribution unit (14) according to any of the proceeding claims 14 - 16, characterised in that, the data communication unit (24) is arranged to transmit collected metering values from said distribution unit (14) over the low voltage distribution cable of said grid (12) to a consumption data collector (26).

18. A distribution unit (14) according to any of the proceeding claims 14 - 17, characterised in that, the data communication unit (24) is arranged to transmit collected metering values from said distribution unit (14) over a radio link.

19. A distribution unit (14) according to any of the proceeding claims 14 - 18, characterised in that, said unit (14) is a cable distribution cabinet (50) located at the splitting site.

20. A distribution unit (14) according to claim 19, characterised in that, inside said cabinet (50) the device (22) is mounted on to a common assembly plate (52) for arranging other connector devices (22) close together.