Abstract:
An electric power meter collar with external electrical connection points enables expedited connection of distributed energy resources to the customer premises or the electric power grid. The meter collar is installed between an electric meter and the meter socket box that the meter would otherwise plug into at the site of a customer who receives two-phase service from an electrical utility company, and has electrical connection points that are electrically upstream and downstream of the meter. It enables “plug and play” connection of on-site power generation resources since the collar includes both a receptacle for a “plug” from on site power generation and overcurrent protection.

Description:
BACKGROUND 
       [0001]    Distributed power generation systems (alternatively “DPGS”) are typically small, i.e., less than 1 MW, power generators that are connected directly to local electric distribution grids. In contrast, conventional large power plants are typically connected to a high-voltage electric transmission grid. Examples of a DPGS may include solar cell arrays, battery or fuel-cell storage systems, electric vehicles, and small wind turbines. 
         [0002]    As developments in DPGS technologies progress, associated costs are falling and performance efficiencies are increasing. As a result, some customers of electric utility companies have expressed a preference for using power which they, the customers, generate or store locally or on-site. Utility companies (alternatively “utility” or “utilities”) are also exploring options for owning and maintaining DPGS at the customer site, often in exchange for a leasing payment to the customer for use of a structure at the customer site. 
         [0003]    Problems that may confront a utility or utility customer seeking to install a DPGS at a customer site may include modifications in wiring of the customer&#39;s private electrical distribution system (the “load-side” network) to accommodate the DPGS at the customer&#39;s residence or at a small business establishment. Installation of new dedicated electrical circuits that comply with necessary safety codes and standards often incur significant money and time expenditures and, moreover, given the rapid speed of evolution in DPGS, a customer may want to upgrade or replace an existing system with a new technology within a relatively short period of time. Replacing the existing technology safely requires another costly changeout of the wiring, thereby reducing the incentive to upgrade. 
       SUMMARY 
       [0004]    In an example, a collar for a watt-hour meter may include one or more sockets that enable a plug-in interface that connects a DPGS to a residential or business structure (alternatively “structure”) or to the distribution grid, while maintaining compliance to interconnection requirements for safety, power quality, and automatic disconnect capabilities. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0005]    The foregoing and other features of this disclosure will become more fully apparent from the following description and appended claims, taken in conjunction with the accompanying drawings. The use of the same reference numbers in different figures indicates similar or identical items. Further, understanding that these drawings depict only several embodiments in accordance with the disclosure and are, therefore, not to be considered limiting of its scope, the disclosure will be described with additional specificity and detail through use of the accompanying drawings, in which: 
           [0006]      FIG. 1   a  shows an overview of a customer site-side system implemented by and for at least one embodiment of a meter collar for plug-in connection of grid-quality DPGS, in accordance with at least some of the embodiments described herein; 
           [0007]      FIG. 1   b  shows an overview of a utility-side system implemented by and for at least one embodiment of a meter collar for plug-in connection of grid-quality DPGS, in accordance with at least some of the embodiments described herein; 
           [0008]      FIGS. 2   a ,  2   b ,  2   c , and  2   d  show a meter collar socket interface point and interior circuit, in accordance with at least some of the embodiments described herein; 
           [0009]      FIGS. 3   a  and  3   b  show a plug-socket interface, in accordance with at least some of the embodiments described herein. 
       
    
    
     DETAILED DESCRIPTION 
       [0010]    In the following detailed description, reference is made to the accompanying drawings, which form a part hereof. In the drawings, similar symbols typically identify similar components, unless context dictates otherwise. The illustrative embodiments described in the detailed description, drawings, and claims are not meant to be limiting. Other embodiments may be utilized, and other changes may be made, without departing from the spirit or scope of the subject matter presented herein. It will be readily understood that the aspects of the present disclosure, as generally described herein, and illustrated in the Figures, can be arranged, substituted, combined, separated, and designed in a wide variety of different configurations, all of which are explicitly contemplated herein. 
         [0011]      FIG. 1   a  shows an overview of a customer site-side (“load side”) system  10  implemented by and for at least one embodiment of a meter collar for plug-in connection of grid-quality DPGS, in accordance with at least some of the embodiments described herein. As depicted, system  10  includes a meter collar  100 , an interface circuit  105 , an externally resettable overcurrent protection device  107 , a meter  110 , a meter socket box  120 , a site-side DPGS  130 , an electricity network  140 , and a distribution grid  150 . Although illustrated as discrete components, various components may be divided into additional components, combined into fewer components, or eliminated while contemplated within the scope of the subject matter disclosed herein. 
         [0012]    Meter collar  100  may be configured as an adapter that is inserted between meter socket box  120  and meter  110 , and may include a housing that is provided with first contacts  103  for connecting with utility-side contacts of meter socket box  120  and that is further provided with second contacts  104  for connecting with customer-side contacts of meter socket box  120 . 
         [0013]    Meter collar  100  may plug into a meter socket of the meter socket box  120 , utilizing connection points  103  and  104  disposed thereon that engage with the connection points of the meter socket box  120 . Meter  110 , in turn, may plug into the meter collar  100 , which has connection points for engagement with the connection points of the meter. Meter collar  100  thus acts as an adapter between meter  110  and meter socket box  120 , and is therefore configured to provide access to a customer&#39;s on-site electricity network  140 . The interface circuits  105  and  106  are capable of connecting to DPGS  130  and  135 , as illustrated and discussed hereafter. 
         [0014]    By placing two or more sockets on meter collar  100 , i.e., one electrically upstream (“line side”) and one electrically downstream (“load side”) of the meter, different ownership models for DPGS may be actuated. The upstream socket  106  may enable a corresponding utility or equivalent wholesale power provider to own the DPGS and to connect the power generator directly to the grid without passing the electrical energy through the customer&#39;s structure or meter. Alternatively, the downstream socket  105  may allow customers to own and to connect the DPGS directly to a private structure for private consumption, with only excess electrical energy being passed back through the meter to the grid. 
         [0015]    According to at least one embodiment, meter collar  100  may house an “upstream” interface circuit  106  between the utility-side connection points of a residential meter box  120  and the utility-side connection points of an electric meter  110 . The upstream interface circuit  106  provides a point of connection and/or disconnection for various types of on-site power generation systems directly with the distribution grid of the electric power utility. The upstream interface circuit  106  is electrically upstream of meter  110 , thus creating a direct conduit between the on-site power and the electric utility distribution grid. Power generation systems connected to the upstream interface  106  are not electrically at the customer site, irrespective of whether they are physically located at the customer site. 
         [0016]    According to at least one other embodiment, meter collar  100  may house a “downstream” interface circuit  105  between the private structure-side connection points of a meter box  120  and the private structure-side connection points of an electric meter  110 . The downstream interface circuit  105  provides an easy point of connection and/or disconnection for various types of on-site power generation systems directly with the electric system of a customer site. The downstream interface circuit  105  is electrically downstream of meter  110 , thus creating a direct conduit between the on-site power and the customer site&#39;s electric grid. Power generation systems connected to the downstream interface  105  are electrically at the customer site, irrespective of whether they are physically located at the customer site. 
         [0017]    In accordance with at least one further embodiment, meter collar  100  may be disposed between a watt-hour electric meter  110  and a meter socket having utility-side contacts  103  that are connected to power lines of a utility and have customer-side contacts  104  that are connected to a load or loads. By such an embodiment, meter collar  100  may include a housing having first contacts  103  to connect to the utility-side contacts of the socket and second contacts  104  to connect to the customer-side contacts of the socket, as well as further contacts for connection with the meter. 
         [0018]    In yet another example embodiment, meter collar  100  may house a standardized electric power socket, which is the upstream power socket, connected to the upstream interface circuit. Therefore when meter collar  100  is disposed between the meter socket box  120  and meter  110 , the upstream power socket may provide a connection point to the upstream interface that is accessible from the outside of the structure upon which the meter box  120  is mounted. Power generation systems configured with the appropriate mate for the standardized electric socket may then be plugged directly into the upstream socket. 
         [0019]    Further still, in accordance with yet another example embodiment, meter collar  100  may house a standardized electric power socket that is connected to the downstream interface circuit. Thus, when the meter collar is installed between the meter socket box  120  and meter  110 , the downstream power socket may provide a connection point to the downstream interface that is accessible from the outside. Power generation systems configured with the appropriate mate for the standardized electric socket may then be plugged directly into the downstream socket. 
         [0020]    With regard to safety of the person(s) connecting the DPGS equipment to the meter collar, a concern is that integrated contact points on either the upstream or downstream circuit may allow exposure to an electrical shock hazard. Thus, in accordance with at least one example embodiment, meter collar  100  may incorporate within the housing an overcurrent protection device  107 , such as a circuit breaker or fuse block, that may be controlled from the exterior of the meter collar  100  to disconnect and reconnect the electrical current within from the circuit connection point or sockets  105 ,  106 . In other circumstances, the overcurrent protection device  107  could also be controlled remotely or automated to reset itself. 
         [0021]    With regard to the protection of the DPGS equipment, a concern is that integrated contact points on either the upstream or downstream circuit may allow surges in current that exceed the capabilities of the DPGS and may damage them or the premises. Thus, in accordance with at least one example embodiment, meter collar  100  may incorporate within the housing an overcurrent protection device  107 , such as a circuit breaker or fuse block, that will automatically open the circuit in the event of a current surge that exceeds the rating of the overcurrent protection. The overcurrent protection device  107  may be controlled from the exterior of the meter collar  100  to disconnect and reconnect the electrical current within from the circuit connection point or sockets  105 ,  106 . In other circumstances, the overcurrent protection device  107  could also be controlled remotely or automated to reset itself. 
         [0022]    With regard to security, a concern is that the upstream socket may allow a customer or third party to connect additional, unmetered, load to the grid (instead of DPGS), in order to steal power. Thus, in accordance with at least one example embodiment, meter collar  100  may include a combination dummy plug  315  and electrical meter seal locking mechanism  340  to secure the sockets  210  and  230  when not in use. The locking mechanism may also secures the DPGS connection when it is in use. 
         [0023]    Further, both the upstream socket and the downstream sockets may be secured with a dummy plug  315  made of electrically non-conducting material that is used to prevent access to the socket when not in use. In at least one embodiment, the dummy plug may be secured to meter collar  100  by a miniature locking ring  340 . The meter locking ring is secured by means of any locking mechanism such as a padlock or security tag. Further still, the meter locking ring may also be used to secure the DPGS to the socket, when installed. 
         [0024]    Accordingly, the combination of meter collar  100 , standardized plug-and-socket interface, automatic outage and overcurrent grid disconnect, and locking mechanism  340 , provide an effective solution that can significantly reduce the costs of deploying DPGS. 
         [0025]    Meter collar  100  may be coupled to electric power meter  110  and to meter socket box  120 . Thus, meter collar  100  may provide a connection point for a customer-owned DPGS  130  to on-site electric network  140 . Electric energy produced by DPGS  130  may flow into on-site electric network  140  at which the electric energy may be either consumed or passed through the electric power meter  110  to electric distribution grid  150 . 
         [0026]    Electric power meter  110  may refer to an electric meter, either mechanical or electronic, that is electrically coupled to electric distribution grid  150  and to on-site electric network  140 ; and which may be configured to measure the flow of electricity therebetween. 
         [0027]    Meter socket box  120  may refer to a dedicated point of interconnection for electric power meter  110  at a site at which electric energy may be consumed, and may be configured to house a socket into which electric power meter  110  or meter collar  100  may be inserted. Wiring may connect electric distribution grid  150  to meter socket box  120  and to electrically upstream connection points for electric power meter  110 . Wiring may further connect electrically downstream points of electric power meter  110  to on-site electric network  140 . 
         [0028]    Site-side DPGS  130  may refer to a DGPS that may be disposed locally and connected to on-site electric network  140  through a connection  105  on meter collar  100  in a configuration that supports direct site-side integration. The connection point may be electrically downstream of electric power meter  110 , although electric energy may flow upstream as well. It is noted that the term “site-side” may be used generically to refer to any locally sited DPGS that is configured to feed directly into on-site electric network  140 . 
         [0029]    On-site electric network  140  may refer to a local system of circuits that may carry electric energy from a point of interconnection with electric power distribution grid  150 , e.g., electric power meter  110 , for consumption on-site. On-site electric network  140  may be disposed electrically downstream of electric power meter  110 , although electric energy may flow upstream as well. 
         [0030]    Electric distribution grid  150  may refer to an electric utility-owned system of wires and equipment that may carry electric energy from a wholesale power grid to the point of interconnection with the on-site electric network  130 . 
         [0031]      FIG. 1   b  shows an overview of a utility-side system implemented by and for at least one embodiment of meter collar  100  for plug-in connection of grid-quality DPGS, in accordance with at least some of the embodiments described herein. 
         [0032]    Meter collar  100  may be coupled to electric power meter  110  and to meter socket box  120 , thus meter collar  100  may be configured to provide a connection point for utility-owned DPGS  135  to the electric distribution grid  150 . Electric energy produced by DPGS  135  may flow into electric distribution grid  150 , at which the electric energy may be either distributed to other points on the grid or passed through the electric power meter  110  to on-site electric network  140  as a part of the electric energy typically sourced from the wholesale power grid. 
         [0033]    Grid-side DPGS  135  may refer to a DGPS disposed locally and connected to electric distribution grid  150  through a connection on meter collar  100  in a configuration that supports direct grid-side integration. The connection point may be disposed electrically upstream of electric power meter  110 , although electric energy may flow downstream, as well. It is noted that that the term “grid-side” may be used generically to refer to any locally sited DPGS that feeds directly into utility electric network  150 . 
         [0034]      FIGS. 2   a ,  2   b ,  2   c , and  2   d  show a meter collar socket interface point and interior circuit, in accordance with at least some of the embodiments described herein, in accordance with at least some of the embodiments described herein. 
         [0035]      FIG. 2   a  shows a front-view of the interior of the meter collar  100 , including socket and connection points  220 ,  240 . 
         [0036]    Utility-side DPGS connector port  210  may protrude from a side of meter collar  100 , which may be cylindrical, and may include at least two contacts  215  corresponding to each phase of standard split or multiple phase electrical service. From contacts  215 , wiring may connect with circuits that may terminate at utility-side meter interface contacts  220 , which are the lower two of the four total meter interface contacts  220 ,  240 . Meter collar  100  may be inserted between electric power meter  110  and meter socket box  120  and create a bridge between the utility-side connection points of meter socket box  120  and the utility-side connection points of the electric power meter  110 . Electric energy produced by DPGS  135  connected to the utility-side DGPS connector port  210  may flow into the electric distribution grid  150 . 
         [0037]    Site-side DPGS connector port  230  may protrude from a side of meter collar  100 , which may be cylindrical, and may include at least two contacts  235  corresponding to each phase of at least two phase electrical service From contacts  235 , wiring may extend to connect with circuits that may terminate in site-side meter interface contacts  240 , which are the upper two of the four total meter interface contacts  220 ,  240 . Meter collar  100  may be inserted between electric power meter  110  and meter socket box  120 , and therefore create a bridge between the site-side connection points of meter socket box  120  and site-side connection points of electric power meter  110 . Electric energy produced by DPGS  135  connected to the site-side DGPS connector port  230  may flow into the on-site electric network  140 . 
         [0038]    Meter interface contacts  220 ,  240 , housed within a socket on meter collar  100  may provide an interconnection point for electric power meter  110 . Electric power meter  110  may either be plugged into a socket of meter collar  100  or otherwise incorporated into meter collar  100  as a single unified device. 
         [0039]    A measurement and communications module  250  may optionally be housed within meter collar  100 . Measurement and communications module  250  uses sensors  260 ,  270 ,  280  and may be disposed in meter collar  100  to measure voltages, currents, and other characteristics of energy flowing through the both phases of both/either the grid-side and/or the site-side DGPS connector ports  210 ,  230  as well as voltages, currents, and other characteristics of energy flowing through the both phases of utility side meter connection points  220  both from the grid to the site as well as from the DGPS at the site to the grid. Such sensors and measurement and communications module may store and transmit data to the utility, the homeowner, or a third party data on the generation of the DGPS as well as the net flow of energy from the grid to the site and from the DGPS at the site to the grid via a variety of available configurable digital communications protocols including but not limited to Internet Protocol, WiFi, Zigbee, Cellular, WiMax, HomePlug, and IPV6, among others. Additional data points may also be captured by the measurement and communication module. 
         [0040]      FIG. 2   b  shows a rear-view interior of the meter collar  100 , displaying embedded connection points  225 ,  245  and internal circuits to meter socket box  120 . Utility-side DPGS connector port  210  may protrude from a side of meter collar  100 , which may be cylindrical, and may include at least contacts  215  corresponding to each sub-phase of standard service. From contacts  215 , wiring may runs downward to connect with circuits that may terminate in utility-side meter socket box interface contacts  225 , which are the lower two of the four total meter socket box interface contacts  225 ,  245 . Meter collar  100  may be coupled to electric power meter  110  and to meter socket box  120  (the intended configuration), and therefore create a bridge between the utility-side connection points of the meter socket box  120  and the utility-side connection points of the electric power meter  110 . Electric energy produced by a DPGS connected to the utility-side DGPS connector port  210  may flow into the electric distribution grid. 
         [0041]    Site-side DPGS connector port  230  may protrude from a side of the meter collar  100 , which may be cylindrical, and may include at least two contacts  235  corresponding to each 110 volt phase of standard 220 volt service. From contacts  235 , wiring may run upward to connect with circuits that terminate at site-side meter socket box  120  interface contacts  245 , which are the upper two of the four total meter interface contacts  225 ,  245 . When meter collar  100  is inserted between electric power meter  110  and meter socket box  120  (the intended configuration), the meter collar  100  creates a bridge between site-side connection points of the meter socket box  120  and site-side connection points of the electric power meter  110 . Electric energy produced by a DPGS connected to the site-side DGPS connector port  230  may flow into the on-site electric network  140 . 
         [0042]    Meter socket box interface contacts  225 ,  245  housed within an interface on the meter collar identical to an interface on a standard electric power meter  110 , provide an interconnection point to a standard meter socket box  120 . In all usages envisioned for the meter collar, it is plugged into the socket of the meter socket box  120 . 
         [0043]    An optional measurement and communications module  250  with sensors  260 ,  270 ,  280  may be housed within the meter collar  100 . The function of the measurement and communications model is the same as detailed in  FIG. 2   a.    
         [0044]      FIG. 2   c  shows an external side view of the meter collar  100 . Electric power meter  110  may plug into a socket encompassing the majority of the top of the figure. Meter collar  100  may plug into meter socket box  140  by means of meter socket box connection points  225 ,  245 . 
         [0045]    Electric power meter  110  may be coupled to meter collar  100  by means of, e.g., a locking ring engaging with a locking lip  300 . Meter collar  100  may be coupled to the meter box by means of an additional industry standard meter locking ring engaging with locking lip  310 . 
         [0046]    Meter collar  100  may include site-side DPGS connector port  230 , which may include a Listed weatherized electric socket or other Listed connection means. The connector port may include contacts  235  also identified in  FIGS. 2   a  and  2   b . Site-side DPGS connector port  230  may be electrically downstream of meter  110 . Utility-side DPGS connector port may be disposed opposite the site-side DPGS connector port  230 , and may be electrically upstream of the meter. Site-side DPGS connector port  230  may be color-coded to help identify whether it is the upstream or downstream port. 
         [0047]    Meter collar  100  may include an externally resettable overcurrent protection device  237 . 
         [0048]      FIG. 2   d  shows an external view of meter collar  100  from the opposite side as  FIG. 2   c . All descriptions are similar to those described in  FIG. 2   c , except that the utility-side DPGS connector port  210  and its associated electrical contacts  215  are electrically downstream of the meter. 
         [0049]      FIG. 3   a  shows a front-view exterior of meter collar  100 , for an example embodiment in which DPGS  130  is plugged-in to site-side DPGS connector port  230 . Also shown are the DPGS interconnection point  310  and locking mechanism  340  as well as the socket and connection points  220 ,  240  for the electric power meter (not pictured). 
         [0050]    Site-side DPGS connector port  230  may protrude from meter collar  100 , which may be cylindrical. Plugged-in to the port is a DPGS plug  310  to which may be attached to DPGS power wires  320 . The DPGS power wires  320  carry electricity from the DPGS. 
         [0051]    DPGS plug  310  may be coupled to site-side DPGS connector port  230  by means of DPGS port locking ring  340  wrapped around locking lips  330  of the port and the plug. The locking ring may lock the plug in place to guard against tampering or theft. 
         [0052]    Meter collar  100  may include an externally resettable overcurrent protection device  333 . 
         [0053]      FIG. 3   b  shows a counterpart to  FIG. 3   a , wherein dummy plug  315  may be plugged into utility-side DPGS connector port  210 . Dummy plug  315  may be used in the place of a DPGS plug, and may be secured to the port using the same locking ring and locking lips combination described in  FIG. 4   a.    
         [0054]    For reference in  FIGS. 3   a  and  3   b , meter connection points  220 ,  240  are shown in the center of the figure and the utility-side DPGS connector port  210  protrudes from the left side of the cylindrical body of the meter collar  100 . Alternatively, the DPGS may be connected to the utility-side DPGS connector, with the positions of DPGS plug and the dummy plug exchanged.