Abstract:
A power generation and control system is easily installed in a consumer household, a business, or an end-user establishment for generating power and preventing power from flowing to a power grid from a consumer circuit during a power outage A communications transceiver is adapted to transmit a permission signal for allowing power generation only after the control system has been installed. The control system can be adapted to replace an existing circuit breaker in a household circuit breaker box and prevents power from traveling from consumer power generators to the grid during a power outage. In the same manner that end-users can add appliances to existing circuits, end-users can easily add additional power generation devices without hiring a professional electrician and without worrying about causing harm to utility workman during power outages.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present invention claims the benefit of U.S. Provisional Patent Application Ser. No. 61/136,342 entitled “Power Generation and Control System” filed Aug. 28, 2008. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention pertains to the art of power generation and power generation control systems and, more particularly, to power generation and power generation control systems that can be easily installed in a consumer household, a business or other end-user establishment. 
         [0004]    2. Discussion of the Prior Art 
         [0005]    In general, large centralized power grids or networks are utilized to provide power to multitudes of consumer households, businesses and other end-users. Distribution of electric power from power plants to households and businesses is conducted over a network of utility lines connected to each residence and business. A standard consumer household, business or end user establishment has a consumer circuit that includes a circuit breaker that controls power to numerous individual circuits, each with its own circuit breaker. Generally, three-phase power is split into two sets of circuit breakers, one per phase, or two separate power phase groupings of circuit breakers. Should something happen to a specific circuit such as having a device attached to the circuit fail, that individual breaker opens and halts the flow of power to the device that failed. Should that individual circuit breaker fail, an upstream breaker opens and cuts the flow of power to all the circuits in the home business or end-user establishment. 
         [0006]    Each of the large centralized power grids is interconnected with various generating stations and substations that supply power to various loads and monitor utility lines for problems. Each of the power grids has a number of disadvantages, including reliance upon certain vital connections to power plants, as well as distribution difficulties during peak power demand periods. One solution to power supply problems is to install one or more power generating devices at a consumer&#39;s residence or business. In some instances, it is desirable to feed extra power generated by such devices back into the centralized grid, where the power may be shared. Such devices preferably include photovoltaics, wind power, hydroelectric generators and fuel cells, along with conventional and variable speed diesel engines, Stirling engines, gas turbines, micro-turbines and hybrid vehicles. Additionally, storage systems, such as batteries, super-conducting, flywheel, pumped water and capacitor types, may also provide power during outages. However, there are a number of problems associated with utilizing such power generation and storage devices. For example, the engineering, permitting and installation costs for a solar panel power generation and control system can be as much as the cost of the equipment being installed. Much of the installation cost results from the necessity of developing engineering documents, obtaining permits and hiring a qualified installer or electrician to connect the system to the centralized power grid based on particular engineering and building code specifications. Each end-user electrical system typically has the same components: a power generation system, a connection to the power grid, safety systems and, preferably, an energy storage device. Although most end-user electrical systems are conceptually the same, each one requires a custom installation. Household appliances such as lamps, radios, stoves, etc. are also connected to the power grid but, unlike power generation systems, anyone can buy and install such appliances without the need for developing engineering documents and hiring qualified installers such as an electrician. 
         [0007]    Although there are many reasons why end-user power generation systems require a custom installation, one major reason they are not “plug and play” in the same way as appliances is that, if during a power grid outage, the end-user power generation system was to feed power back to the grid, it would become a danger to utility workers handling power lines. Household appliances such as lamps, radios, stoves, etc. present no such risk because they do not generate or provide power and, therefore, anyone may install them without developing engineering documents, obtaining permits or hiring an electrician. More specifically, when a utility line needs maintenance or repair, the lines are disconnected from the power grid and the utility workers assume that no power is being supplied to the line. If there is end-user power supplied to the line downstream of a disconnect point, that assumption could be fatal. 
         [0008]    One such scenario is depicted in  FIG. 1 , showing a consumer household, business or other end-user establishment  20  including an end-user electric power generation system  25  in communication with a power grid  26  via a power line  28 . A standard main circuit breaker  30  is provided between end-user electric power generation system  25  and power line  28 , which connects to the main power grid  26  through switch  48 . As depicted, households  40  are supplied with power  44  produced by a power plant  46 . When an outage occurs, power  44  is blocked at switch  48  in order for a utility worker  50  to work on power line  28 . However, end-user supplied power indicated by arrow  55  from electric power generation system  25  may continue to flow through power line  28 , endangering the utility worker  50 , and may even flow into an end-user establishment  60 . This situation shows the importance of hiring a qualified electrician  61  when installing prior art electric power generation system  25 . 
         [0009]    One solution to such a problem is set forth in U.S. Patent Application Publication No. 2002/0036430 directed to a local area grid for distributed power. The &#39;430 document notes that a utility can impress a “kill” signal on main power grid lines for power conditioning unit disconnect from a grid for servicing. This connection allows power utilities to monitor and track power flow. However, such a system requires expensive installation by trained professionals and relies on an external signal to be sent by the utility in order to provide a measure of safety for utility line workers. 
         [0010]    Based on the above, there is a need for a power generation and control system allowing for the transfer of power between a power generator and a power line that eliminates the possible danger to utility workers and can be quickly and inexpensively installed by anyone. 
       SUMMARY OF THE INVENTION 
       [0011]    The present invention is directed to a system that prevents power from flowing back into a power grid during a power outage and prevents end-user installable power generation systems from operating on a power circuit that does not have this protection. As such, the invention provides all the necessary components for power generation systems so that they can be purchased and installed by anyone without the added expense of engineering documents, permits or qualified installers such as electricians. 
         [0012]    In a preferred embodiment of the invention, a power generation and control system is easily installed in a consumer household, a business or an end-user establishment; generates power; and prevents power from flowing to a power line from a consumer circuit during a power outage. The end-user electrical system power generation and control system includes a main power flow controller for controlling a flow of power between the power grid and the consumer circuit. The controller includes an input adapted to be connected to the power grid and an output connected to the consumer circuit. A power sensor associated with the controller senses if power is in the power line or if there is a flow of power between the power grid and the consumer circuit. A power control switch located between the power sensor and the output interrupts the flow of power between the power line and the consumer circuit when the power sensor senses a power outage in the power line and there is power being generated in the consumer circuit that is flowing to the power grid. In another preferred embodiment, a communications transceiver is adapted to transmit a permission or enabling signal across the consumer circuit. Alternatively, the communications transceiver is adapted to transmit the signal wirelessly or through separate dedicated wires. The power generation controller includes a power generation transceiver adapted to receive the signal generated by the power line communications transceiver. The power generation controller ensures that the power generation device will only operate when it receives permission from the power flow controls through the consumer circuit connecting the controller and generators. This ensures that the controller is upstream of and controls the specific consumer power circuit of the generator. Once the power generator controller is installed, anyone can easily connect the power generation device without hiring a professional electrician knowing that repairmen will be safe in the event of a power outage. 
         [0013]    In another preferred embodiment, a power storage unit is in communication with the power generation device and adapted to store power generated by the power generation device. The power storage unit provides a relatively low voltage power signal to power the power flow controller during an outage and can provide power to start the power generation device. In another preferred embodiment, when the power generation device is not providing power, the power generation device can be activated to supply relatively low voltage power to the power flow controller during a power outage and provide power to activate the power flow controller so that it can isolate the consumer circuit from the power circuit and grant permission to the power generator to supply power to the consumer circuit. This handles the situation when all power is off and the power generator is desired to be on but cannot receive permission to do so from the power controller because the power controller has no power to operate. 
         [0014]    In yet another preferred embodiment, the control system is adapted to replace an existing circuit breaker in a household circuit breaker box. As such, the control system includes a circuit breaker that trips when it senses a power overload, thus protecting household electrical equipment on the consumer circuit. The control system may comprise a filter for stopping the enabling signal from entering the power line and another filter for stopping signals traveling from the power line to the consumer circuit such that no external signals turn on the power generating device. However, a filter is not required because the power generator can communicate with the power controller by drawing significant power (e.g., one amp) in an on/off fashion with a pattern generator to communicate with the power controller. Because it is drawing power, the main controller can only see this signal if the controller is absolutely upstream of the generator. 
         [0015]    The system is installed in a consumer household or a business establishment by installing the power generation control system and user establishment generating a permission signal to indicate the presence of the control system; and enabling the power generation device to provide power only when the permission signal is provided by the control system. Preferably, this method also includes monitoring the power line to determine whether there is power on the power line and preventing power from flowing from the consumer circuit to the power line when there is no power on the power line, while allowing power to flow from the consumer circuit to the power line when there is power on the power line. Preferably, the method also includes supplying power to the control system with a relatively low voltage signal during a power outage. The method allows installation of the power generation device without requiring an electrician to modify the consumer circuit. 
         [0016]    Additional objects, features and advantages of the present invention will become more readily apparent from the following detailed description of preferred embodiments when taken in conjunction with the drawings wherein like reference numerals refer to corresponding parts in the several views. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]      FIG. 1  depicts a situation in which a lineman is endangered by a prior art power generation and control system; 
           [0018]      FIG. 2  depicts a situation in which a lineman is safe when a power generation and control system according to a preferred embodiment of the present invention is utilized; 
           [0019]      FIG. 3  is a schematic of the power generation and control system of  FIG. 2  during a normal power event generally showing a power flow controller and a power generation device; 
           [0020]      FIG. 4  is a diagram of the power flow controller of  FIG. 3 ; 
           [0021]      FIG. 5  is a diagram of a power generation device of  FIG. 3 ; and 
           [0022]      FIG. 6  is a schematic of the power generation and control system of  FIG. 2  during a power outage event and also depicting a feedback configuration. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0023]    With initial reference to  FIGS. 1-3 , a consumer household, business or other end-user establishment  20  is provided with a power generation and control system  62  in accordance with a preferred embodiment of the invention. Power generation and control system  62  is shown in communication with power line  28 , which receives power  44  through switch  48  from power grid  26 . A main power flow controller  65  of the present invention, provided between an end-user power generation device  70  and power line  28 , prevents any undesirable power feedback (corresponding to power feedback  55  shown in  FIG. 1 ) from flowing to power line  28  from power generation device  70 . As more fully explained below, power generation device  70  is installable by an end-user  68  and does not require an electrician  61  to install. 
         [0024]    An overview of power generation and control system  62  of the present invention is depicted in  FIG. 3  Power generation and control system  62  includes power generation device  70  and power flow controller  65 . In the preferred embodiment shown, power flow controller  65  has an input  71  connected to line  28  and an output  72  connected to a line  78 . Power flow controller  65  constitutes a circuit breaker upstream from power generation device  70 . Optionally, a power storage unit  85  may also be utilized, either alone, or as part of power generation device  70 . During a normal power event, power flow controller  65  controls a flow of power  44  supplied by power grid  26  through power line  28 , and thus controls the flow of power  86  to branch circuits  87 ,  88  and  89  located downstream of power flow controller  65 . Of course, circuits  87 ,  88  and  89  could be located in a household, a business or in any end-user establishment. In a manner known in the art, individual circuit breaker  96  controls power  86  from output  72  to is branch circuit  87 , while individual circuit breaker  98  controls power  86  from output  72  to branch circuit  88 . Although depicted as a main circuit breaker, it should be understood that power flow controller  65  could optionally constitute a branch circuit breaker between a main breaker and power generation device  70 , such as individual circuit breaker  99 . Preferably, circuit breakers  65 ,  96 ,  98  and  99  are all housed in a household circuit breaker box  100  within household or business  20 . 
         [0025]      FIG. 4  will now be referenced in detailing, power flow controller  65  of the present invention. Power flow controller  65  includes control circuitry  150  in communication with a power sensor  152 , a power control switch  154 , a first transceiver  56  and a power flow monitor  158 . Although only one switch  154  is shown, it should be understood that additional switches could be utilized in the system. Power sensor  152  senses whether there is power in power line  28 . During a power outage, power flow monitor  158  will signal control circuitry  150  of the outage so that power flow controller  65  may respond to the outage. Power control switch  154  is situated to open if power generation device  70  is providing power during a power outage on power line  28 , thus separating power generation device  70  from power line  28 . Additionally, standard circuit breaker protection circuitry  160  is provided between consumer circuit  162 , which includes branch circuits  87 ,  88  and  89 , and power line  28 . More specifically, circuit breaker protection circuitry  160  will open a switch, such as power control switch  154 , in the event consumer  162  draws too much power. 
         [0026]    First transceiver  156  may be, for example, an X10, HomePlug™ or wireless transceiver such as a Zigbee™ transceiver, and is utilized to send signals to and exchange data with one or more power generation devices  70 . Optionally, a filter  164  may be provided between transceiver  156  and power grid  26  to prevent transceiver  156  from sending signals to or receiving signals from other end-user establishments  60 . Power flow monitor  158  is adapted to determine whether one or more power generation devices  70  downstream of power flow controller  65  supply power to power line  28 . Line  166  represents a neutral power line. 
         [0027]      FIG. 5  will now be referenced in detailing power generation device  70  of the present invention. Power generation device  70  includes a pattern generator  165  in control circuitry  170  in communication with a power load switch  172  controlling power flow to a power load  173 , a second transceiver  174 , a power sensor  175 , a power control switch  176  and a relatively low voltage power control switch  177 . Second transceiver  174  may be, for example, an X10, HomePlug™ or wireless transceiver such as a Zigbee™ transceiver, and is utilized to accept signals from and exchange data with power flow controller  65  upstream from power generation device  70 . Alternatively, the two transceivers may communicate through a wire or other communication system. Additionally, a power generator  178  is provided to generate power. In a preferred embodiment of the present invention, generator  178  is in the form of solar panel cells, although it should be readily understood that any type of power generator might be utilized with the present invention. For example, generator  178  may be a group of batteries or a gas/diesel fueled generator or the combination of batteries and fueled generator in a hybrid vehicle. 
         [0028]    In a preferred embodiment, power flow controller  65  is adapted for use with multiple power generation devices  70 . When consumer  68  desires to install power generation and control system  62 , consumer  68  will install or have installed power flow controller  65  between power line  28  and consumer circuit  162 . Preferably, a licensed professional electrician  61  will conduct the installation of the power flow controller  65 . Once power flow controller  65  is installed, the consumer  68  may choose one or more desired types of power generation devices  70 , such as a solar panel type power generator device. Advantageously, after power flow controller  65  is connected, the consumer or anyone for that matter  68  may install one or more power generation devices  70  without the aid of electrician  61 . 
         [0029]    In a manner known in the art, when standard circuit breaker protection circuitry  160  of power flow controller  65  senses that too much power is being supplied by power line  28 , power control switch  154  is tripped and power can no longer flow between power line  28  and consumer circuit  162 . 
         [0030]    The manner in which the present invention is utilized in the event of power being supplied by power line  28  and a desire to have power generation device  70  provide power to branch circuits  87 ,  88 ,  89  and power line  28  will now be discussed with reference to  FIGS. 4-6 . Power on branch circuit  89  is sensed by power sensor  175 . A request signal to provide power is sent by power generation device  70  via second transceiver  174  to any power flow controller  65 . Each power flow controller  65  communicates via first transceiver  156  requesting power generation device  70  to respond with a confirmation that power flow controller  65  is between power generation device  70  and power line  28 . In the preferred embodiment, power load switch  172  is toggled on and off in a particular pattern by a pattern generator  165  located within control circuitry  170  so that a signal measured by timed changes in current flow is generated by power load  173  and is sensed by power flow monitor  158 . When power flow monitor  158  can sense the timed changes in current flow from power generation device  70 , it responds via first transceiver  156  to second transceiver  174  and thus to control circuitry  170  with a signal permitting power generation device  70  to provide power. Control circuitry  170  then closes power control switch  176  allowing power to flow from power generator  178  to branch circuit  89 . When power grid  28  is providing power and power generation device is providing more power than is consumed by branch circuits  87 ,  88  and  89 , such excess power from power generation system  70  flows back into power grid  28  for use by others such as households  40  and adjacent house  60 . In this example, if individual circuit breaker  98  was also a power flow controller, when power generation device  70  responds to the request for a signal to a power flow controller located at  98 , that power flow controller would not sense the response and thus would not respond with permission for power generation device  70  to provide power to branch circuit  89 . 
         [0031]    The manner in which the present invention is utilized in the event of no power being supplied by power line  28  or to branch circuit  89  and a desire to have power generation device  70  provide power to branch circuits  87 ,  88  and  89  will now be discussed with reference to  FIGS. 4-6 . The assumption is that power control switch  154  is closed such that power line  28  is connected to line  78 . No power on branch circuit  89  is sensed by power sensor  175 . Low voltage power control switch  177  is turned on by control circuitry  170  to put relatively low voltage power onto branch circuit  89 . This relatively low voltage power is below the safety threshold of concern for power utilities and is used to provide power to power flow controller  65  when power grid  28  is not supplying acceptable power. The power from low voltage power control switch  177  flows to power flow controller  65  enabling it to open power control switch  154  to isolate power line  28  from consumer circuit  162 . A request to provide power is sent by power generation device  70  via second transceiver  174  to any power flow controller  65 . Power flow controller  65  communicates via first transceiver  156  requesting power generation device  70  to respond with a signal that confirms that power flow controller  65  is between power generation device  70  and power line  28 . 
         [0032]    In the preferred embodiment, instead of a power load, power generation device  70  uses pattern generator  165  to produce relatively low power voltage fluctuations to signal to power flow controller  65  that they are on the same circuit. Low voltage power control switch  177  varies the voltage supplied to branch circuit  89  so that power flow monitor  158  senses timed changes in the relatively low voltage. When power flow monitor  158  can sense the signal from power generation device  70 , it responds via first transceiver  156  to second transceiver  174  and thus to control circuitry  170  with a signal permitting power generation device  70  to provide power. Control circuitry  170  then closes power control switch  176  allowing power to flow from power generator  178  to branch circuit  89 . Control circuitry  170  then turns off low voltage power control switch  177 . In this example, if individual circuit breaker  98  was also a power flow controller, power provided by low voltage power control switch  177  would allow that power flow controller to open its power control switch to isolate branch circuit  88  from line  86 . The power flow controller at  98  would cease to receive relatively low voltage power on its downstream branch circuit  88  connection and it would not respond to the request to provide power sent by power generation device  70 . 
         [0033]    The manner in which the present invention is utilized in the event of a power outage on power line  28  while power generation device  70  is providing power to branch circuits  87 ,  88  and  89  and power line  28  will now be discussed with reference to  FIGS. 4-6 . In a manner known in the art, power flow monitor  158  senses that no power is being supplied via power line  28  or senses whether power is flowing in an appropriate direction between consumer circuit  162  and power grid  26 . It should be noted that power could flow toward or away from power grid as represented by arrows  186 . Control circuitry  150  isolates power line  28  from consumer circuit  162  by opening power control switch  154 . Power generation device  70  continues to provide power to branch circuit  89 . 
         [0034]    The manner in which the present invention is utilized in the event that power generation device  70  is physically disconnected from branch circuit  89  will now be discussed with reference to  FIGS. 4-6 . In a manner known in the art, power sensor  175  senses that no power is being supplied via branch circuit  89  and that no power is flowing to branch circuit  89 . A request to provide power is sent by power generation device  70  via second transceiver  174  to any power flow controller  65 . Because no power flow controller is physically connected to power generation device  70 , permission is not granted and power generation device  70  opens power control switch  176 . Should power generation device  70  be reattached to a branch circuit that is not protected by a power flow controller, it will not put power onto that unprotected branch circuit. 
         [0035]    The initial request to provide power signal is sent by second transceiver  174  by power generation device  70  (see  FIG. 6 ). When a power flow controller  65  receives the signal it responds through transceiver  156 . The communications between transceiver  156  and transceiver  174  can be transmitted separate from the power lines  89  and  78 . A permission signal  180  must travel through power lines  89  and  78  to confirm that power flow controller  65  protects power line  28  from power generation device  70 . Once signal  180  is confirmed, communications between transceiver  156  and transceiver  174  contains information communicating that specialized power flow controller  65  of the present invention is in place, rather than a conventional circuit breaker. When permission to provide power is granted by power flow controller  65  to power generation device  70  via transceiver  156  and transceiver  174 , power control switch  176  is flipped, allowing power generated by power generator  178  to flow to consumer circuit  162  in a safe manner. If signal  180  is not received by power flow controller  65 , permission to provide power is not granted to power generation device  70  and power control switch  176  will remain in an off or deactivated position, and no power will be provided to consumer circuit  162 . Signal  180  is preferably checked for only when power generator  178  is about to be activated. However, the signal  180  may be checked periodically or continuously, in which power generator  178  will only be enabled upon detection of the signal during a signal check. Optionally, a continuous signal may be utilized and is particularly advantageous in a system that experiences frequent power outages. 
         [0036]    A user may press an actuator  189  in communication with power flow controller  65  to instigate a signal event that causes all power generation devices granted permission to operate by power flow controller  65 , to cease providing power to consumer circuit  162  so that the branch circuits are fully off and can be worked on by a qualified electrician  61 . 
         [0037]    Although described with reference to preferred embodiments of the invention, it should be readily understood that various changes and/or modifications could be made to the invention without departing from the spirit thereof. For instance, although only one power generation device  70  is depicted, any desirable number of power generation devices may be utilized.