US20020135232A1

US20020135232A1 - Method and apparatus for distributing electric power

Info

Publication number: US20020135232A1
Application number: US09/815,388
Authority: US
Inventors: Glenn McMillan
Original assignee: Xantrex International Inc
Current assignee: Xantrex International Inc
Priority date: 2000-10-13
Filing date: 2001-03-22
Publication date: 2002-09-26
Also published as: CA2342484A1; US20020057146A1; CA2342483A1; CA2342484C; US6570269B2

Abstract

An electric power distribution system includes a first power distribution apparatus for distributing power to individual load circuits from a main power source and a second power distribution apparatus adjacent the first apparatus. The second panel has a base, an electric power distribution conductor supported by the base for providing electric power from the alternate electric power source and a load circuit selector site on the base and is operable to supply power from the main electric power source and the electric power distribution conductor to a signal-controlled selector installed at the load circuit selector site.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Patent Application Ser. No. 60/239,918, filed Oct. 13, 2000.

BACKGROUND OF THE INVENTION

1. Field of Invention

This invention relates to methods, apparatus and systems for distributing electric power, and for distributing electric power to a load circuit from main and alternate electric power sources.

2. Description of Related Art

Increasing numbers of critical appliances or devices such as computers, alarm systems or heating/cooling systems are being employed in commercial buildings and residences. Many of these appliances and/or devices require a continuous supply of electrical power. Most residential and commercial buildings are wired for AC electric power supplied only from a single utility electric power source. In some areas this utility electric power source can be unreliable or expensive. Consequently, it is desirable to be able to use alternate sources of electric power as backup electric power sources to ensure a continuous supply of electric power or as less expensive electric power source alternatives.

Commonly, alternate electric power sources such as generators and inverters, for example, are wired to separate circuits and separate outlets or are used as alternate electric power sources to a conventional AC electric power distribution panel normally supplied with electrical power from an electric power utility. Connecting individual appliances to separate circuits or separate outlets is impractical, as a user would have to connect each appliance to an appropriate outlet to receive electric power from either the main electric power source or the alternate electric power source, as required. Many generators, for example, have built in AC receptacles by which they supply electric power but can only accommodate a few appliances.

Alternatively, individual devices or appliances can be wired directly to a separate electric power distribution system which may be connected to a transfer mechanism operable to receive electric power from two AC electric power sources. This is often done where critical load circuits are to be backed up by an alternate AC electric power source. These load circuits are usually removed from the main electrical panel and wired into a secondary sub-panel. This sub-panel is then powered through a manual transfer switch or automatic transfer switch for controlling electric power supplied to the entire secondary panel. When AC electric power failure occurs from one source only those devices wired to the separate electric power distribution system are operable to draw electric power from the other AC electric power source.

The main disadvantage of the above system is that every device or appliance needing backup electric power must be wired to this special, separate electric power distribution system, which may require substantial re-wiring of circuits throughout a building. This has the additional disadvantage of limiting the locations the devices or appliances can be placed, and necessitates circuit rewiring when devices or appliances are moved.

In addition, sourcing an entire AC electric power distribution panel with an alternate source requires the ability to switch large currents which mandates the use of expensive high current switching equipment. In conventional high current systems which provide for switching of an electric power distribution panel feed from a conventional high current AC source to an alternate source, transfer speeds are relatively slow because of the large ampere ratings of the relays required to be actuated. Furthermore, the distance required between contacts of this type of transfer device increases proportionately to the current carrying capacity. Sub-panel transfer relays are relatively large and very slow, making them impractical for sub-panels supplying computers and process control equipment.

What would be desirable therefore is a simple way of extending an electric power distribution panel to provide for an alternate power supply to selected circuits, without rewiring of load circuits and without requiring high current switching capacity.

SUMMARY OF THE INVENTION

The above problems are addressed by providing a method for distributing electric power involving distributing electric power from an alternate electric power source to a plurality of selector sites and supplying power from the alternate electric power source or from a main electric power source to at least one load circuit, through a signal-controlled selector at at least one of the plurality of selector sites.

Distributing electric power may include conducting current on an electric power distribution conductor in proximity to the plurality of selector sites, where a base may support the conductor, the plurality of selector sites and a plurality of signal lines to carry control signals to respective signal-controlled selectors.

The method may also include providing at least one control signal for controlling at least one signal-controlled selector and supporting, on the base, a controller operable to produce the at least one control signal or a connector for receiving control signals from a remotely located controller.

The method may also include providing overload current protection to the load circuit when electric power is supplied to the load circuit from the alternate electric power source. This may be facilitated by providing a plurality of overload current protection mounting sites in proximity to corresponding selector sites to provide for mounting and connection of overload protection devices in series with the alternate electric power source and respective selector sites.

In accordance with another aspect of the invention there is provided an apparatus for distributing electric power to a load circuit from a main electric power source and an alternate electric power source. The apparatus includes a base, an electric power distribution conductor supported by the base for providing electric power from the alternate electric power source, and a load circuit selector site on the base and operable to supply power from the main electric power source and the electric power distribution conductor to a signal-controlled selector installed at the load circuit selector site.

The apparatus may further include the signal-controlled selector, which may be operable to selectively connect the load circuit to the main electric power source or to the electric power distribution conductor, in response to a control signal.

The base may have a plurality of selector sites to support a plurality of signal-controlled selectors and the base may support a plurality of signal lines for carrying control signals to respective signal-controlled selectors at respective selector sites.

The apparatus further may include at least one overload current protection mounting site on the base and associated with the at least one selector site to provide for mounting of an overload current protection device for, protecting the load circuit when electric power is supplied to the load circuit from the alternate electric power source. The overload current protection device may be mounted at the overload current protection mounting site and may include a circuit breaker.

The apparatus may further include a signal-controlled selector operable to be received in the selector site for selectively connecting the load circuit to the main electric power source or to the electric power distribution conductor in response to a control signal.

The apparatus may further include a controller for providing at least one control signal for controlling the signal-controlled selector. The controller may include a processor circuit supported by the base, for example. The apparatus may also or alternatively include a connector supported by the base for receiving the control signals from a remotely located controller. Or the apparatus may include a wireless receiver or transceiver for receiving at least one control signal for controlling the signal-controlled selector.

In accordance with another aspect of the invention, there is provided an electric power distribution system including a first power distribution apparatus for distributing power to individual load circuits from a main power source, and a second power distribution apparatus adjacent the first apparatus, the second apparatus having a base, an electric power distribution conductor supported by the base for providing electric power from an alternate electric power source and a load circuit selector site on the base and operable to supply power from the main electric power source and the electric power distribution conductor to a signal-controlled selector installed at the load circuit selector site.

Using specific embodiments of the invention provided herein, the base may be mounted right beside an existing main electric power distribution panel, permitting load circuit wires to simply be removed from the main panel and moved a few inches (centimeters) to connect to the base. Thus, rewiring of load circuits is relatively simple and does not require a separate remotely located subpanel as with conventional alternate supplies. Through use of the embodiments of invention described herein, the need to completely rewire panels in existing buildings to supply circuits with alternate sources of electric power is removed. In addition, the need for a secondary sub-panel in new construction is removed. Furthermore, use of such embodiments provides for safer installation by having only one place within a given building to disconnect a load from AC electric power and by ensuring that backfeed of electric power into the utility or into the alternate source cannot occur. Power transfer occurs at the load circuit level and therefore switching is done on currents of lesser magnitude which enables smaller components to be used in the selectors, such smaller components having less mass and requiring less spacing than higher current apparatus, resulting in faster transfer speeds, rendering embodiments of the invention more suitable for use with computers and process control equipment.

Other aspects and features of the present invention will become apparent to those ordinarily skilled in the art upon review of the following description of specific embodiments of the invention in conjunction with the accompanying figures.

BRIEF DESCRIPTION OF THE DRAWINGS

In drawings which illustrate embodiments of the invention, [0024]
FIG. 1 is a pictorial representation of a system for distributing power according to a first embodiment of the invention; and [0025]
FIG. 2 is a pictorial representation of an alternate power distribution apparatus shown in FIG. 1. [0026]

DETAILED DESCRIPTION

Referring to FIG. 1, a system for distributing electric power is shown generally at [0027] 100. The system 100 includes a first power distribution apparatus, which in this embodiment includes a main electric power distribution panel shown generally at 102 for providing electric power to individual load circuits from a main power source such as an electric utility supplier. The apparatus further includes at least one alternate power distribution apparatus such as apparatus 104 or 106 respectively, each for distributing electric power to at least one load circuit from the main electric power source, through the conventional main electric power distribution panel or from an alternate electric power source such as a power conversion device or generator, for example. The power conversion device may include an electric power inverter, for example. In this embodiment, the apparatuses 104 and 106 are located on opposite sides of and adjacent to the main electric power distribution panel 102. Thus, close proximity of apparatuses 102, 104 and 106 makes it easy to simply transfer load circuit terminations from the main electric power distribution panel 102 to new terminations on the alternate power distribution apparatuses 104 and 106, as will be seen below. This eliminates the need to rewire or splice existing load circuits and ensures that all electrical power distribution connections are located at or adjacent to the main electric power distribution panel 102, maintaining the focus of electric power distribution at or about the main electric power distribution panel and desirably not distributed about a premises. The apparatuses 104 and 106 could however be located away from the main electric power distribution panel 102, but this would usually require splicing extensions onto the load circuits.
Referring to FIG. 2, in this embodiment, each apparatus such as [0028] apparatus 106 includes a base 110, an electric power distribution conductor 112 supported by the base for providing electric power from the alternate electric power source, and includes a load circuit selector site such as site 130 on the base operable to supply power from the main electric power source and the electric power distribution conductor 112 to a signal-controlled selector 114 installed at the load circuit selector site.
In this embodiment, the [0029] base 110 is formed from a printed wiring board on which is printed a plurality of copper electric power distribution conductors or traces, two of which, 112 and 116, act as an electric power bus 118 for supplying electric power from an alternate source. Each electric power distribution conductor 112 and 116 may be connected to a separate phase (line) of an AC supply, for example. This facilitates use with multiple phase supplies, such as three-phase supplies, for example. Referring to FIG. 1, neutral conductors of the supply are connected to a neutral bus 127 of the main electric power distribution panel 102. The copper traces 112 and 116 may be terminated at one end of the base, in a first set of first and second terminals, such as screw terminals 120 and 122, to which wires (not shown) from the alternate electric power source may be connected to receive electric power from the alternate electric power source. The copper traces 112 and 116 may also be terminated at an opposite end of the base 110, in a second set of screw terminals 121 and 123 to facilitate connection to an adjacent apparatus such as apparatus 125 shown in FIG. 1, to facilitate expansion of the electric power bus 118, through the installation of additional apparatuses of the type described herein.
In this embodiment, the [0030] base 110 has a plurality of selector “sites” including the first selector site 130 and a second selector site 132 at which respective signal-controlled selectors, such as 114 and 115 can be installed to control the supply of electric power to respective associated load circuits. These sites may provide relay sockets, for example, or direct solder connections for mounting relays or other switching devices which may act as signal-controlled selectors operable to selectively connect the load circuit to the main electric power source or to the electric power distribution conductor 112 and 116, in response to a control signal.
To do this, referring to FIGS. 1 and 2 each [0031] selector site 130,132 has a main terminal 134 for receiving electric power by means of a wire 135, from a circuit breaker 136 housed in a circuit breaker receptacle of the main electric power distribution panel 102. Each selector site 130 and 132 also has an output terminal 138 for terminating a conductor such as a wire 143 for providing electric power to a load circuit connected thereto.
Referring to FIG. 2, in this embodiment each [0032] selector site 130,132 further includes traces 141,143 on the base 110 from the main terminal 134 and the output terminal 138 respectively, terminated in pads or mounts 140 and 142 respectively, for connection thereto of a first contact and a common contact, respectively, of a signal-controlled selector 114 or 115 mounted at the site. In a direct current (DC) system, each electric power distribution conductor 112 and 116 may be connected to a separate or the same DC system pole, such as a positive (+) terminal and the opposite pole such as the negative (−) terminal may be connected to the neutral bus 127. It would even be possible to connect an AC power source to one conductor 112, for example and a DC power source to the other conductor 116, for example to produce a hybrid system.
Each [0033] selector site 130,132 also includes a pad or mount 144 for connection to a second contact of the respective signal-controlled selector 114 or 115 and includes a trace 145 leading to a pad or mount 147 of an overload current protection mounting site 146 on the base and associated with the selector site to provide for mounting of an overload current protection device 148. A suitable overload current protection device 148 may include a fuse or circuit breaker element, for example, which serves to protect an associated respective load circuit connected to the output terminal 138 from excessive currents supplied by the alternate source. Overload current protection is provided when the load circuit is supplied from the main source, by the circuit breaker 136 in the main electric power distribution panel 102.
Each [0034] selector site 130,132 also has control and common coil pads or mounts 150 and 152 for terminating control and common coil contacts, respectively, of a signal-controlled selector 114 for supplying electric power to a coil 154 thereof. Circuit traces 156 and 158 extend from these pads and trace 158 is, in this embodiment, terminated at a contact 160 of a connector 162 supported by the base 110, while trace 158 is connected to a common coil pad of each site and is ultimately terminated at a common contact 164 at the same connector 162. Other circuit traces 166 similar to traces 156 extend from respective control pads of respective selector sites 130,132, to respective contacts on the connector 162.
The [0035] coils 154 or actuators of respective signal-controlled selectors 114 are controlled by signals received on respective pins of the connector 162. Thus, the traces 156 and 158 act as a plurality of signal lines which are supported on the base 110 for carrying control signals to respective signal-controlled selectors 114.
The [0036] coil 154 of any given signal-controlled selector 114 controls a contactor 168 thereof to selectively electrically connect the common contact pad 142 to either the first contact pad 140 or the second contact pad 144 to cause the common contact pad to be supplied with electric power from either the main electric power source or the alternate electric power source. Thus the coil 154 acts to selectively connect the load circuit to the main electric power source or to the electric power distribution conductor 112 in response to a control signal.
Signals for controlling respective signal-controlled [0037] actuators 154 may be provided by a controller 170, such as a microprocessor control circuit, which selectively provides control signals for energizing respective signal-controlled selectors 114,115 to determine whether or not a respective corresponding load circuit is supplied with electric power from the main electric power distribution panel 102 or from the alternate source supplying electric power to the electric power distribution conductor 112.
In this embodiment, the [0038] controller 170 is mounted separate from the apparatus 106 and is operable to provide control signals through the connector 162. The controller 170 may be a circuit on a power inverter, for example, located remotely from the electric power distribution system 100. It should be noted that in an alternate embodiment the controller may be mounted on the base 110 such as shown in broken outline at 172, and the control signal traces, or a subset thereof, may be connected directly thereto in which case the connector 162 may not be needed.
In another alternate embodiment, the connector may be replaced with a wireless receiver or transceiver for receiving wireless signals from a remote device for controlling the signal controlled [0039] selectors 114,115. Such a wireless receiver or transceiver may be of the type provided under the trademark BLUETOOTH™ owned by Telefonaktiebolaget L. M. Ericsson of Sweden.
The [0040] apparatus 106 provides a convenient way of extending a main electric power distribution panel 102 into an electric power distribution system 100 which is operable to supply electric power from either a main electric power source or an alternate electric power source. As shown in FIG. 1, simply by mounting the apparatus 106 adjacent to an existing main electric power distribution panel 102, wires from load circuits leading to the existing electric power distribution panel may easily be disconnected and connected to the output terminals 138 of respective selector sites 130,132 of the apparatus 106. In addition, typically only two wires, a line and neutral wire, may be required to be run from the alternate electric power source to the apparatus 106 in order to distribute electric power to each of the selector sites 130,132 through the electric power distribution conductor 112. Thus the apparatus may quickly be installed and operational in a relatively short period of time.
As stated above, the control signals, no matter how they originate or are received, determine which load circuits are to be supplied from the main or alternate power sources. This easily facilitates selective load sharing between power sources and may be used to isolate loads being supplied from different sources. In areas subject to brown-outs, for example, essential appliances may be supplied from the main or utility power source while luxury appliances may be supplied from the alternate supply. [0041]
While specific embodiments of the invention have been described and illustrated, such embodiments should be considered illustrative of the invention only and not as limiting the invention as construed in accordance with the accompanying claims. [0042]

Claims

What is claimed is:

1. A method for distributing electric power, the method comprising distributing electric power from an alternate electric power source to a plurality of selector sites and supplying electric power from said alternate electric power source or from a main electric power source to at least one load circuit, through a signal-controlled selector at at least one of said plurality of selector sites.

2. The method of claim 1 wherein distributing comprises conducting current on an electric power distribution conductor in proximity to said plurality of selector sites.

3. The method of claim 2 further comprising supporting said electric power distribution conductor and said plurality of selector sites on a base.

4. The method of claim 3 further comprising supporting a plurality of signal lines on said base to permit said plurality of signal lines to carry control signals to respective signal-controlled selectors.

5. The method of claim 4 further comprising providing at least one control signal for controlling at least one signal-controlled selector.

6. The method of claim 5 further comprising supporting on said base a controller operable to produce said at least one control signal.

7. The method of claim 5 further comprising supporting on said base a connector for receiving said control signals from a remotely located controller.

8. The method of claim I further comprising providing overload current protection to said load circuit when electric power is supplied to said at least one load circuit from said alternate electric power source.

9. The method of claim 1 further comprising providing a plurality of overload current protection mounting sites in proximity to corresponding selector sites to provide for mounting and connection of overload protection devices in series with said alternate electric power source and respective selector sites.

10. An apparatus for distributing electric power to a load circuit from a main electric power source and an alternate electric power source, the apparatus comprising:

a base;

an electric power distribution conductor supported by said base for providing electric power from said alternate electric power source; and

a load circuit selector site on said base and operable to supply power from said main electric power source and said electric power distribution conductor to a signal-controlled selector installed at said load circuit selector site.

11. The apparatus of claim 10 further comprising the signal-controlled selector installed at said load circuit selector site, wherein said signal-controlled selector is operable to selectively connect the load circuit to said main electric power source or to said electric power distribution conductor in response to a control signal.

12. The apparatus of claim 11 further comprising a signal line supported by said base for carrying said control signal to said signal-controlled selector.

13. The apparatus of claim 12 further comprising a controller for providing said control signal for controlling said signal-controlled selector.

14. The apparatus of claim 13 wherein said controller comprises a processor circuit supported by said base.

15. The apparatus of claim 13 further comprising a means supported by said base for receiving said control signal from a remotely located controller.

16. The apparatus of claim 10 further comprising at least one overload current protection mounting site on said base and associated with said load circuit selector site to provide for mounting of an overload current protection device.

17. The apparatus of claim 16 further comprising an overload current protection device mounted at said overload current protection mounting site.

18. The apparatus of claim 17 wherein said overload current protection device comprises a circuit breaker.

19. The apparatus of claim 10 wherein said base supports a plurality of overload current protection mounting sites associated with separate respective load circuits.

20. The apparatus of claim 19 further comprising a plurality of signal-controlled selectors, each one being installed in a respective load circuit selector site.

21. The apparatus of claim 20 further comprising a controller for providing respective control signals to said plurality of signal-controlled selectors.

22. The apparatus of claim 20 further comprising a connector for receiving respective control signals, and signal lines on said base for communicating said control signals to said plurality of signal-controlled selectors.

23. The apparatus of claim 20 further comprising a plurality of overload current protection mounting sites on said base, each overload current protection mounting site being associated with a respective load circuit selector site to provide for mounting of a respective overload current protection device in said each overload protection mounting site.

24. The apparatus of claim 23 further comprising a plurality of overload protection devices, each one being installed in a respective overload current protection mounting site.

25. An electric power distribution system comprising:

a first power distribution apparatus for distributing power to individual load circuits from a main power source; and

a second power distribution apparatus adjacent said first apparatus, said second apparatus having a base, an electric power distribution conductor supported by said base for providing electric power from an alternate electric power source and a load circuit selector site on said base and operable to supply power from said main electric power source and said electric power distribution conductor to a signal-controlled selector installed at said load circuit selector site.

26. An apparatus for distributing electric power to a load circuit from a main electric power source and an alternate power source, the apparatus comprising:

a base;

means supported by said base for providing electric power from said alternate electric power source; and

means for supplying power from said main electric power source and from said means supported by said base to a device on said base for selectively supplying power from said main electric power source or from said means supported by said base to said load circuit.

27. The apparatus of claim 26 wherein said base includes a printed wiring board and said means for supplying power comprises traces on said printed wiring board.

28. The apparatus of claim 27 further including mounts connected to said traces and arranged to form a selector site to facilitate mounting of a signal-controlled selector thereon.

29. The apparatus of claim 27 further including a plurality of mounts and traces arranged to form a plurality of selector sides on said base to facilitate mounting of a plurality of respective signal-controlled selectors.

30. The apparatus of claim 29 further comprising means for carrying control signals to said plurality of respective signal-controlled selectors.

31. The apparatus of claim 30 further comprising means for providing at least one control signal for controlling at least one signal-controlled selector.

32. The apparatus of claim 30 further comprising means for receiving said control signals from a remotely located controller.

33. The apparatus of claim 26 further comprising means for providing overload current protection to said load circuit when electric power is supplied to said load circuit from said alternate electric power source.

34. The apparatus of claim 26 further comprising means for mounting overload current protection devices on said base for protecting respective load circuits.