Abstract:
A power load center comprises a first terminal block adapted to receive multiple high voltage DC power feeder pairs under normal operating conditions and a protector block adapted to receive the multiple high voltage DC power pairs from the first terminal block and to aggregate them.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present invention is a continuation of U.S. patent application Ser. No. 11/196,974 entitled EXPRESS POWER LOAD CENTER, filed Aug. 4, 2005 which is related to and claims the benefit of U.S. provisional patent application Ser. No. 60/598,861 entitled EXPRESS POWER LOAD CENTER, filed Aug. 4, 2004, both of which are assigned to the assignee of the present invention, the entire contents of each of which are incorporated by reference as if produced in their entirety herein. The present invention is further related to and claims the benefit of U.S. provisional patent application Ser. No. 60/424,277, entitled TELECOMMUNICATIONS INTERFACE, filed on Nov. 6, 2002 and U.S. non-provisional patent application Ser. No. 10/631,096, entitled TELECOMMUNICATIONS INTERFACE, filed on Jul. 31, 2003, U.S. provisional patent application Ser. No. 60/592,353 entitled REHABILITATING A SERVING AREA INTERFACE CABINET AND TERMINAL FIELD WITHOUT SERVICE INTERRUPTION, filed Jul. 29, 2004, U.S. non-provisional patent application docket number INFRATEL.0018, entitled REHABILITATING A SERVING AREA INTERFACE CABINET AND TERMINAL FIELD FOR BROADBAND SERVICES WITHOUT SERVICE INTERRUPTION, filed Jul. 29, 2005, U.S. non-provisional patent application Ser. No. 11/005,274 entitled REMOTE POWER NODE, filed Dec. 6, 2004, U.S. non-provisional patent application Ser. No. 11/021,883 entitled EMBEDDED HEAT EXCHANGER, filed Dec. 23, 2004, U.S. provisional patent application Ser. No. 60/628,433 entitled TELECOMMUNICATIONS INTERFACE ENHANCEMENTS, filed Nov. 16, 2004, U.S. provisional patent application Ser. No. 60/662,074, entitled DSLAM ENCLOSURE, filed Mar. 15, 2005, U.S. provisional patent application Ser. No. 60/662,073, entitled FTTC DSLAM OVERLAY, filed Mar. 15, 2005, and U.S. provisional patent application Ser. No. 60/662,072, entitled ENCLOSURE HOUSING MULTIPLE DSLAMs, filed Mar. 15, 2005, assigned to the assignee of the present invention, the entire contents of each of which are incorporated by reference as if produced in their entirety herein. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention is related to power provisioning and, more specifically, to an express power load center. 
       BACKGROUND OF THE INVENTION 
       [0003]    Telephone companies are working on ways of extending broadband services to as many of their customers as possible. This means that they must find ways to reach substantially all their customers with digital subscriber lines (DSLs). In order to do so, they are installing more and more electronics such as DSLAMs and broadband loop carriers (BLCS) in remote locations away from central offices (COs) and remote terminals (RTs). Naturally, this electronic and fiber equipment needs to be powered. If local power is to be used, an AC service and an expensive AC to DC converter must be provided at the remote site, along with batteries for power backup and the recharging circuitry to go along with them. As an alternative to AC power, the concept of providing DC power from the CO or other convenient point by using existing copper cable feeder pairs has many advantages. However, connecting multiple cable pairs to each individual DLSAM or other device could prove to be unwieldy, costly and cumbersome. Termination of the pairs, electrical protection, and DC to DC conversion would need to be provided for each DSLAM, fan tray, fiber multiplexer, etc., sometimes at the board level. Clearly, a solution that overcomes these limitations is needed. 
       SUMMARY OF THE INVENTION 
       [0004]    The present invention discloses an express power load center for use in powering remote telecommunication nodes, such as nodes that have been established as part of new installations (Greenfield), nodes that have been created by a retrofit or rehabilitation of an existing service area interface cabinet (SAIC), nodes that are required due to the broadband upgrades or replacements of existing Digital Loop Carriers or Remote Terminals, nodes that provide power to environmentally sealed Mini-DSLAMs in OSP (Outside Plant) cabinets, or nodes that power wireless installations, such as cellular and WiMAX. Express power, which is also called network power or Optical Network Unit (ONU) power, allows a remote cabinet to be powered by sending power to the cabinet from another remote cabinet or from the CO. Such power can be transported to the remote site over twisted pair copper (either in the same cable sheath as voice and data or over a separate copper cable) or over copper conductors in composite cable (which includes fiber and copper in the same sheath) or over coaxial power cables. In all instances, an express power cable is connected to the remote cabinet via pin pairs in the express power protection panel or through express terminal blocks. 
         [0005]    Express power is typically used in a number of scenarios. For example, when AC power cannot be delivered to a remote site or cannot be delivered economically, when greater reliability and control over cabinet powering is desired, when a centralized power distribution scheme is desired for fiber-to-the-curb, FTTC, or fiber-to-the-home, FTTH broad band deployments, when greater back-up power than can be provided by local batteries is desired, or when local AC power is subject to frequent interruptions. Conventional line-powered systems must be designed for the peak load on the equipment. With the load varying over time (both short-term and long term) according to traffic demand, such conventional designs must be designed for the peak load and are, therefore, inefficient. When a DSLAM is first installed, for example, the load will be small. As more customers are connected, both the average and peak loads will increase. When the first DSLAM shelf is exhausted, and a second is installed, there will be an increase in the electrical load at the site. There are similar variations in the load represented by fans, battery heaters, and other ancillary devices. For example, the fans will not operate as much at night or in the winter, and the battery heaters will not typically operate in the summer. The present invention scales to match long term variances in the load. Further, batteries are used to “chop off the peaks” of the short term variances and feeder pairs can be added as necessary as customers and traffic grow at the site without using as many pairs as if the equipment was powered separately. 
         [0006]    In one embodiment, a power load center comprises a first terminal block adapted to receive multiple high voltage DC power feeder pairs, such as +/−190V DC, a protector block adapted to receive the multiple high voltage DC power pairs from the first terminal block, a DC to DC voltage converter adapted to receive aggregate high voltage feeder pairs and convert them to the required electronic supply voltage, typically −48V DC, and a second terminal block to provide multiple −48V DC power taps. A second embodiment incorporates the above high voltage converting mechanism, but also includes rechargeable batteries, battery heater, and the necessary electronic circuitry to recharge the battery as well as monitor the status of the load center. 
         [0007]    In another embodiment, a power load center comprises a first terminal block adapted to receive multiple high voltage DC power feeder pairs, a protector block adapted to receive the multiple high voltage DC power pairs from the first terminal block, a DC to DC voltage converter adapted to receive the multiple feeder pairs and convert them to −48V DC, and a power tap bus or second terminal block adapted to deliver the −48V DC power and to output it as multiple −48V DC power taps. 
         [0008]    In a further embodiment, a method for powering a combined electronic and serving area interface cabinet comprises receiving at least one high voltage power feeder pair, wherein the feeder pair is at least one of: +/−130V DC, around +/−130V DC, and above +/−130V DC, a protector block adapted to receive the multiple high voltage DC power pairs from the first terminal block, aggregating the at least one high voltage power feeder pair with at least one other high voltage power feeder pair, receiving the aggregate feeder pairs, converting the aggregate feeder pairs to at least one of: −48V DC, around −48V DC, and above −48V DC, receiving the converted power, and outputting the converted power as multiple power taps, wherein the power taps are at least one of: −48V DC, around −48V DC, and above −48V DC. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  depicts an express power load center block diagram utilized in a combined electronic and SAI cabinet, wherein batteries are providing power for peak loads according to one embodiment of the present invention; 
           [0010]      FIG. 2  depicts an express power load center block diagram wherein batteries are utilized to provide power for the loads directly according to one embodiment of the present invention; and 
           [0011]      FIG. 3  depicts an express power load center block diagram according to one embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0012]    Referring now to  FIG. 1 , an integrated electronic and serving area interface (SAI) cabinet  10  is depicted. Such a cabinet is described in more detail in one or more of the pending cross-referenced patent applications. Generally, the integrated electronic and SAI cabinet  10  includes an SAI side  12 , and an electronic side which includes DSLAMs  14 , a battery compartment  16 , and protection for DSLAM IN and OUT blocks  18 . An express power load center of the present invention is depicted as being located in a housing  20  of the cabinet  10 . Although depicted as such, the power load center may be housed in various other locations of the cabinet  10  and may be distributed throughout the cabinet  10 . 
         [0013]    The power load center of the present invention comprises a terminal block  22  which is adapted to receive incoming pairs, such as +/−190V DC feeder pairs, via a same cable, a separate cable, a composite cable, a coax cable, and the like. The terminal block  22  is coupled to a protector block  24 . The incoming pairs are fed into a DC-to-DC converter. The +/−190V DC power is then converted via a DC to DC converter  28  to −48V DC, sent via a −48V output bus  30  to a power tap  32  (or second terminal block). Individual −48V DC power connections are made to various components at a remote site such as DSLAMs  24 , fans  36 , heat exchangers and air conditioning  38 , fiber optic equipment  40 , and the like. 
         [0014]    Charger electronics  42  are coupled to the DC to DC converter  28  to provide charging to maintain the floating voltage of the batteries. The charger electronics  42  are coupled to batteries  44  which are primarily used to provide additional power during peak demand and for additional usage requirements. A load sensor  48  is coupled to the output bus  30 , to permit load sharing capabilities and to monitor the load. 
         [0015]    In one embodiment, the present invention allows for the use of multiple high voltage power pairs, such as +/−190V DC power pairs to provide power to the SAIC node. The incoming pairs are terminated on a block and aggregated into a power bus. The +/−190V DC is then converted via a DC to DC converter to −48V DC or other such voltage as required by the fiber and electronic equipment, and the output is available on multiple −48V DC taps. Individual −48V DC power connections are made to various electronic and fiber components present at the remote site such as: DSLAMs. Broadband Loop Carrier (BLC) equipment, battery heaters, battery recharging circuitry, heat exchanger or air conditioning equipment, fiber optic equipment, wireless electronics, cooling fan(s), and the like. Further, batteries are included to supplement power during peak loading of the electronic and fiber equipment. Although not a requirement, the power load center may be placed in a remote telecommunication node that is established by a retrofit or a rehabilitation of a serving area interface cabinet (also known as a cross-connect cabinet), or a retrofit or a rehabilitation of both a service area interface cabinet and a remote terminal (or digital loop carrier). Surge protection is also available for the high voltage power feeder pairs via a protector block, and rechargeable batteries can be used to supplement operating power during peak fiber and electronic equipment load periods. 
         [0016]    The features of the present invention include: 
         [0017]    1) An express power load center brings in multiple +/−190V DC power feeder pairs from the CO, a digital loop carrier remote terminal, a remote power node, or other remote location and terminates them at one place. It also outputs multiple −48V DC power taps at one place. This allows for load sharing thereby reducing the number of power pairs for each site. As previously noted, DC power can be sent to the cabinet via HDSL pairs, heavy gauge coax, and the like (which may be advantageous in cases where telcos are placing a new fiber feeder to the site). Further, voltages of +/−130V DC and above can be used without departing from the scope of the present invention; 
         [0018]    2) By bussing the input and output power to one DC to DC converter, the converter function is not repeated at each DSLAM shelf, reducing board components and space; 
         [0019]    3) Wiring is simplified, since input and output power connections can be accommodated at one location; 
         [0020]    4) Integral surge protection of the incoming feeder pairs can be provided via the input bus prior to the converter without the need to protect each feeder pair from surges and other transient voltages; 
         [0021]    5) The unit could turn on indications when the load nears capacity. This could signal the telco to hook up some more power feeder pairs. It would also alarm the telco to the fact that one or more power input pairs may have failed; and 
         [0022]    6) A potential problem with express power is that, as the cabinet gets filled with equipment, the power load during peak periods can exceed what can be supplied from a reasonable number of +/−190V DC power pairs. In one embodiment of the present invention, a plurality of rechargeable batteries (which are, for example, Lithium batteries because of their size and maintainability) are used to supplement the power inputs during such peak periods. These batteries are not back-up batteries (which can be utilized by the express power load center). The express power load center trickle-charges the plurality of batteries during low usage times, and then brings them on line when the voltage on the −48V DC bus falls below a predetermined level. 
         [0023]    Referring now to  FIG. 2 , another power load center of the present invention, which may be used in a number of cabinets, comprises a terminal block  22  (which is adapted to receive +/−190V DC feeder pairs) which is electrically coupled to a protector block  24 . The incoming pairs (which, for example, currently exist and are received from an existing facility) are aggregated into an input bus  26 . The +/−190V DC is then converted via a DC to DC converter  28  to −48V DC, sent via a −48V output bus  54  to a power tap  32  (or second terminal block) via a load sensor  56  that permits load monitoring capabilities to monitor the source of input power to individual −48V DC power connections made to various components at a remote site such as DSLAMs  24 , fans  36 , heat exchangers and air conditioning  38 , fiber optic equipment  40 , and the like. A −48V DC power supply  50  is coupled to the DC to DC converter  28  and to the batteries  52 . In this scenario, the batteries  52  (and not the DC to DC converter  28 ) are providing all the load power. 
         [0024]    The embodiments described above are only exemplary. Even though several characteristics and advantages of the present invention have been set forth in the foregoing description together with details of the method of the invention, the disclosure is illustrative only and changes may be made within the principles of the invention to the full extent indicated by the broad general meaning of the terms used in the attached claims. 
         [0025]    Referring now to  FIG. 3 , another embodiment is presented whereby the high voltage input feeds  57  the DC to DC converter and battery charger  58  and the DC output of the converter such as 48V DC, 60V DC and the like is electronically monitored by a load sensor  59  for the purpose of monitoring and sending alarm and status information in the event of low or missing input feed power, low output power, low battery voltage, and whether output DC power is being provided by the batteries  44  or  52  or the DC to DC converter. Referring to the embodiment above, such alarms may be remotely sent by the equipment being powered or directly from the express power load center. 
         [0026]    In another embodiment, the high voltage input feeds  57  the DC to DC converter and battery charger  58  and the DC output of the converter such as 48 VDC, 60 VDC and the like is split between the output power buss and a trickle charging circuit connected to the batteries in order to maintain the batteries at a fully charged state. The batteries are arranged so as to discharge into the output power buss, as required, during periods of peak power usage so as to maintain the output power buss at its nominal voltage level. 
         [0027]    Although an exemplary embodiment of the present invention has been illustrated in the accompanied drawings and described in the foregoing detailed description, for example in relation to  FIG. 3 , it will be understood that the invention is not limited to the embodiments disclosed, but is capable of numerous rearrangements, modifications, and substitutions without departing from the spirit of the invention as set forth and defined by the following claims. For example, a greater number of elements such as terminal blocks, protector blocks, converters, power supplies, batteries, sensors, power taps and the like can be employed with the present invention.