Abstract:
An automatic metering system in accordance with the principles of the invention comprises a plurality of groups of geographically related utility meters. Each utility meter comprises an interface unit operable to accumulate usage data and to transmit the usage data over power lines utilizing power line carrier. The system further comprises a plurality of data forwarding apparatus each comprising power line carrier communication apparatus operable to receive usage data from each utility meter in its group of utility meters. Each data forwarding apparatus comprises a first wireless communication module. Each data forwarding apparatus has a geographic relationship to its corresponding group of utility meters. A computer is located geographically apart from the plurality of data forwarding apparatus. The central computer comprises a second wireless communication module and operates cooperatively with each data forwarding apparatus to upload usage data from all of the utility meters via the plurality of data forwarding apparatus.

Description:
FIELD OF THE INVENTION  
       [0001]     This invention pertains to automated utility company meters reading systems, in general, and to watt-hour metering systems and methods for the measurement of electrical energy consumption for revenue metering applications, in particular.  
       BACKGROUND OF THE INVENTION  
       [0002]     Typically, electrical power supplied for residential and small business applications is single-phase alternating current power. To measure the consumption of electricity in residential applications, a utility company meter is provided at the electrical service entrance to the residence.  
         [0003]     Utility company meters are of three general types, namely, electromechanical based meters, purely electronic component based meters, and hybrid electromechanical/electronic meters. The electromechanical and hybrid type meters are essentially an induction motor in which the moving element is a rotating disk. The speed of rotation of the disk is directly proportional to the voltage applied and the amount of current flowing through the motor. The phase displacement of the current, as well as the magnitude of the current, is automatically taken into account by the meter, i.e., the power factor influences the speed of rotation of the disk. The result is that the disk rotates with a speed proportional to true power. In the electromechanical type of meters, a register is used to register the number of revolutions, and the gearing is arranged to be read directly in kilowatt-hours.  
         [0004]     The electric utility meters most commonly in use are of the electromechanical type. The meters are generally highly reliable, but do not lend themselves to remote or automated reading.  
         [0005]     Hybrid meters typically utilize electronic circuitry in combination with the rotating disk to permit at least limited two-way communication to/from the meter. Typically, the two-way communication is limited to reading the meter via a proprietary communications link that frequently is a limited range radio frequency link.  
         [0006]     It is not uncommon for electric utilities to utilize both simple and complex tariffs. The tariffs may be time of use type tariffs, or may be changed from time to time or on predetermined dates to provide for various time of use type of rates.  
         [0007]     It is common practice for utility companies to access meter information on only a monthly or 30 day period. In many systems, a meter reader actually views the meter and manually records the meter reading.  
       SUMMARY OF THE INVENTION  
       [0008]     In accordance with the principles of the invention a low cost automatic meter reading system is provided. The system of the invention utilizes a data pooling or concentration approach to lower capital equipment costs on a per customer basis. The system architecture is layered such that the cost of more complex and expensive apparatus is distributed over the customer base.  
         [0009]     The present invention provides the next generation of time-sensitive advanced metering data collection and management solutions for utilities and energy service providers. The meter and system of the invention provide unmatched two-way, secure, access to meter reading over wide geographic areas.  
         [0010]     The system measures residential energy consumption and automatically communicates this information to a host computer. The host computer can then be accessed by the end utility customer or other authorized entities. This Internet or web based system offers two-way communication capability to support meter reconfiguration.  
         [0011]     An automatic metering system in accordance with the principles of the invention comprises a plurality of groups of utility meters. Each group of utility meters comprises a group of geographically related utility meters. Each utility meter comprises an interface unit operable to accumulate usage data and to transmit the usage data over power lines utilizing power line carrier. The system further comprises a plurality of data forwarding apparatus each comprising power line carrier communication apparatus operable to receive usage data from each utility meter in its group of utility meters. Each data forwarding apparatus comprises a first wireless communication module. Each data forwarding apparatus has a geographic relationship to its corresponding group of utility meters. A computer is located geographically apart from the plurality of data forwarding apparatus. The central computer comprises a second wireless communication module and operates cooperatively with each data forwarding apparatus to upload usage data from all of the utility meters via the plurality of data forwarding apparatus.  
         [0012]     In accordance with one aspect of the invention, at least one data forwarding apparatus comprises apparatus operable to communicate usage data from another one of the data forwarding apparatus to the computer. Each data forwarding apparatus is operable in accordance with a routing algorithm to determine a communication path to said computer. The communication path to said computer may be a direct communication path to the computer or an indirect communication path to said computer. The direct communication path comprises a first spread spectrum radio frequency communication link. The indirect communication path comprises a second spread spectrum radio frequency communication link between a first one of the data forwarding apparatus and a second one of the data forwarding apparatus.  
         [0013]     In accordance with another aspect of the invention the computer forwards the usage data from the utility meters to a database for storage.  
         [0014]     In accordance with another aspect of the invention each meter interface unit comprises a module installed in an existing utility meter. Each module comprises a meter portion that gathers meter data and a modem portion. Each meter portion comprises a pulse acquisition circuit coupled to the meter to receive pulses having a relationship to electricity usage; a micro-controller for receiving, and processing said pulses to generate usage data, and operable to cause said usage data to be transmitted via the modem portion to a corresponding data forwarding apparatus. The meter portion comprises a memory for storing a unique meter number. The memory also stores an initial meter reading and meter constants.  
         [0015]     In accordance with another aspect of the invention, the central computer is automatically operable to selectively initiate uploads of data from each of meter interface units via the data forwarding apparatus.  
         [0016]     In accordance with another aspect of the invention each utility meter of at least one group of utility meters comprises a second interface unit operable to accumulate usage data and to transmit the usage data over a public switched telephone network; and at least one of the data forwarding apparatus is operable to receive usage data via the public switched telephone network and transmit the received usage data to said computer.  
         [0017]     In accordance with another aspect of the invention each utility meter of at least a second group of utility meters comprises a third interface unit operable to accumulate usage data and to transmit the usage data over a wireless link. At least one data forwarding apparatus is operable to receive usage data via the wireless link.  
         [0018]     A system in accordance with the invention utilizes a scalable architecture that permits power usage data to be collected, calculated and stored incrementally for automatic transmission.  
         [0019]     In accordance with the principles of the invention a method of remotely configuring a utility meter, includes the steps of providing the meter with a unique physical meter number and providing the meter a unique electronic serial number. Further in accordance with the invention the method includes: providing a communication link between the meter and a database, the database being physically remote from said utility meter; storing in the database the unique physical number and the unique electronic serial number; storing in the database information relative to the account to which the meter is assigned; storing in the database rate schedule information for the account; and downloading the rate schedule information from the database to the meter. A server or data concentration computer is utilized to control communications and access to and from the database. 
     
    
     BRIEF DESCRIPTION OF THE DRAWING  
       [0020]     The invention will be better understood from a reading of the following detailed description in conjunction with the drawing figures in which like reference numerals are used to designate like elements, and in which:  
         [0021]      FIG. 1  is a block diagram of a meter reading and control system in accordance with the principles of the invention;  
         [0022]      FIG. 2  is a block diagram of a meter interface unit utilized in the system of  FIG. 1  in accordance with the principles of the invention;  
         [0023]      FIGS. 3 and 4  are block diagrams of data forwarding units utilized in the system of  FIG. 1  in accordance with the principles of the invention; and  
         [0024]     FIGS.  5  is a block diagram of a data concentrator utilized in the system of  FIG. 1  in accordance with the invention. 
     
    
     DETAILED DESCRIPTION  
       [0025]     Each utility meter is required to record the electricity consumption at a particular premises. With the advanced metering provided by a system in accordance with the principles of the invention, it is possible to support a number of different pricing plans. These plans vary the cost of electricity of the consumer according to the time of day and/or maximum load that the consumer draws from the utility grid. The system described here allows a utility company to remotely control the schedule programming of individual meters from a central computer. All information relating to calendars, daily schedules (On peak, Off peak, shoulder  1  and shoulder  2  rate time intervals) and seasonal information is downloaded annually from the database server or whenever there is a change required (such as a rate change or if a customer changes from a flat rate kWh plan to a Time of Use plan).  
         [0026]     In accordance with the principles of the invention, a new and novel system and method for acquiring metered information is provided. The system in which the meters  FIG. 1  shows an automatic meter reading system  1  in accordance with the principles of the invention. The system of the invention provides all the features of an automatic meter reading system but by selective distribution of technologies utilized it has a lower cost per end user account than prior automatic meter reading systems.  
         [0027]     A significant feature of the invention as shown in  FIG. 1  is that a layered architecture is utilized. System I includes pluralities of groups  101  of meter interface units  102 ,  103 ,  104 . Each of the meter interface units  102 ,  103 ,  104  has a bi-directional communication port coupled to a link  105  for transmission and reception of data between a power meter and a data forwarder  109 . Link  105  for meter interface units  103  is a bi-directional power line carrier link. Link  105  for meter interface unit  102  is a bi-directional wireless link  108 . Link  105  for each meter interface unit  104  is a bi-directional link  106  over the public switched telephone network (PSTN). Each group of meter interface units  102 ,  103 ,  104  is coupled by a corresponding link  105  to a corresponding data forwarder unit  121 . Data concentrator computer  121  is coupled to the public switched telephone network via a communication link  124  and also includes direct links power lines for a power line carrier bi-directional link  122 .  
         [0028]     Data concentrator computer  121  is connected via a communication link  125  to a Host computer  127  co-located at a data center  129 .  
         [0029]     Meter interface unit  102 ,  103 ,  104  is shown in  FIG. 2  along with a representative meter which is shown in phantom. Meter interface unit  102 ,  103 ,  104  is an integrated unit that is adapted to be retrofitted in a power meter that produces pulse output signals. In the illustrative embodiment, each meter interface unit  102 ,  102 ,  104  is implemented on a printed circuit board that is mountable in the power meter.  
         [0030]     Each meter interface unit comprises a modem portion  203  that is changed according to the nature of the communications link  105  that data is to be communicated over and a meter portion  201  that gathers meter data and exchanges data via modem portion  203 .  
         [0031]     Meter portion  201  includes a pulse signal interface  205  coupled to the meter and coupleable to a hand held device that is utilized to provide initial meter programming. Pulse acquisition circuit  207  for providing conditioned pulses to a pulse acquisition circuit  207  receives meter pulses or input pulses and provides them to micro-controller  209 . Micro controller  209  has EEPROM  211  coupled thereto. A unique silicon ID is fused in this EEPROM  211 . Through a hand held device, the unique meter number, initial meter reading and meter constants are programmed into EEPROM  211 .  
         [0032]     Modem portion  203  comprises a modem module  213  Modem module  213  may be a standard type of modem that is commercially available. In the illustrative embodiment, modem module  213  is selected to have a bit rate of 2400 bps, 19.2 Kbps or 100 Kbps based on the need.  
         [0033]     Coupler circuit  215  is used to couple modem module  213  to a power line and provides power line carrier modulation and demodulation for meter interface units  103 . Coupler circuit  215  provides an interface to the public switched telephone network in meter interface units  104  and provides an of interface for the wireless meter interface units  102 .  
         [0034]     Specifications for meter interface units in the illustrative embodiment are set forth in Table 1.  
                                                                     TABLE 1                       Description   Specification                                Pulse   Voltage   0-5 V   Rising edge                   active           Pulse width   50 ± 20 ms           Min. duration        20 ms           between pulses       Communication   Power Line   Modulation   DSSS       with DCU   Carrier   Operating   9-110 kHz               frequency               Baud rate   9600 bps           Power   1-phase-2-wire           distribution           Communication   Half-duplex, bi-               directional           Error detection   CRC       Communication   RS-232cable   Baud rate:       with       4800 bps       Handheld       Programming       Unit            Initialization   TTL level, RXD, TXD, GND3-wire   Initialization       Port   connection   when power off            Serial data   Start bit   1 bit               Stop bit   1 bit           Data bit   8 bit       Initialization   Meter Constant   Meter   6 digit decimal       Parameters   Meter Window   Actual value   Max.           Base Value       Digit YYYYY           Address code   8 digit   Leading 0               decimal       Supply Voltage   AC220 V ± 20%   Line           50/60 Hz   Neutral       Operating   +5 V       voltage   −5 V       Power   Idle    0.1 W       Consumption   Active   0.25 W   At transmission       Tariff   4   Peak, Semi-               peak, Normal,               Low       Time-of-use   12       Optional       Memory   EEPROM   4K Bits       Capacity                  
 
         [0035]     Turning now to  FIGS. 3 and 4 , data forwarders  102 ,  103  are illustrated for use with a wireless link  108  and a power line carrier link  105 , respectively. The designs of the two data forwarders  102 ,  103  are substantially the same with the principal difference being the use of a wireless modem module  401  or a power line carrier modem module  301 . Each data forwarder  102 ,  103  is a stand alone unit comprising a microprocessor  305  and associated random access memory  307  and a memory  309  which may be a flash memory or the like. The microprocessor  305  may be any commercially available microprocessor such as an ARM7TDMI with 1 MB of RAM  307 , 24K of EEPROM  309  and with two serial ports  303 ,  311 . An identification is stored in flash memory  309 . A wireless spread spectrum modem module  313  couples to wireless links  115 ,  117 . Each data forwarder  109  is encased in a weatherproof enclosure.  
         [0036]      FIG. 5  shows the data concentrator  121 . Data concentrator  121  includes a stand-alone computer  501 . Associate with computer  501  are networking ports and storage capacity on hard disk drives and other memory typically associated with computers. A spread spectrum modem module  503  is interfaced to computer  501  via one of computer ports  507 . A PLC modem module  509  is interfaced to computer  501  via port  513 . A PSTN modem is interfaced to computer  501  via port  519 .  
         [0037]     Data concentrator computer  121  comprises a host computer  127  along with network of computers  129 . Computer  121  is a high-end computer, which is connected to data concentrator computer  121  and to a network of computers  129 . Computer  121  may be a commercially available computer and in the illustrative embodiment is an Intel Pentium- 4  based computer system with large RAM and Hard disk drive capacity of at least 30 GB.  
         [0038]     Host computer  127  is connected to the network of computers  127  through Ethernet or a wireless LAN network.  
         [0039]     Specifications for the data concentrator computer  121  in the illustrative embodiment are set forth in Table 2.  
                                                                                             TABLE 2                       Description   Specification                                Communication   Ethernet       2-10 MBPS       with HCU   PSTN   V3.4 or   4800 bps or               above   above       Local   RS-232       communication       Serial data   Start bit   1 bit           Stop bit   1 bit           Data bit   8 bit       Communication   Power Line   Modulation   DHSS       with Meter   Carrier   Operating    110 kHz       MIU, MMIU       frequency               Baud rate   9600 bps           Power   1-phase-2-wire           distribution           Communication   Half-duplex, bi-               directional           Error detection   CRC           Phase detection   Zero-crossing       Communication   Wireless   Modulation   9600 bps       with Meter       MIU, MMIU       Communication   PSTN   Standard   2400 bps       with Meter       MIU, MMIU       Data file format   Standard text file       Data Storage   HDD   20 GB            Software platform   Windows/DOS/Linux            Supply Voltage   AC220 V ± 20%   1 phase               50/60 Hz       Tariff   4   Peak, Semi-peak,               Normal, Low       Time-of-use   12            Status indicators   DCC has a fixed phone number/            Operating   Storage   −40C-+85C           Environment   temp.           Operating   −20C-+70C           temp.           Relative   5%-95%   Non-           Humidity       condensing                  
 
         [0040]     Each meter interface unit  102 ,  103 ,  104  counts pulses coming from its associated meter, converts the pulses into a meter reading and stores the meter reading in memory. Each meter interface unit  102 ,  103 ,  104  also implements a protocol for two-way communication to report the meter reading and meter activity to the Data concentration computer  121  via its associated modem module  213 . Micro-controller  209  implements protocol for two-way communication to modem  213  and to data concentrator computer  121 . Communication between each meter interface unit  102 ,  103 ,  104  through its associated data forwarder  109 .  
         [0041]     Each data forwarder  109  is device receives and forwards data coming from data concentration computer  121  to the meter interface units  102 ,  103 ,  104  or data coming from each meter interface unit  102 ,  103 ,  104  to data concentration computer  121 . Each data forwarder  109  also functions as a router for other data forwarder units  121  connected to different groups  101  of meter interface units which may not be accessible by its associated data concentration computer  121 .  
         [0042]     In operation the data concentration computer  121  makes a request to a data forwarder  110  first. Data concentration computer  121  then receives meter data via wireless radio frequency spread spectrum links  117 ,  119 . Each time data is received by a data forwarder  109  from data concentration computer  121 , the data is analyzed by the data forwarder  109  for routing to other data forwarders via a spread spectrum data link  119  or is to be sent on to a meter interface unit  102 ,  103 ,  104  in the group  101  associated with the data forwarder  109  for uploading usage related information from the associated meter. The response of the meter is reported back to data concentration computer  121  via the respective data forwarder  109 .  
         [0043]     A primary function of data concentration computer  121  is accumulating data from all the various meters coupled to the system via meter interface units  102 ,  103 ,  104  and forwarding the accumulated information to data center network  129  through host computer  127 . Data concentrator computer  121  temporarily stores the accumulated information obtained from the associated meters and forwards it via host computer  127  to data center network  129  for billing and other related processing.  
         [0044]     Host computer  127  is utilized to set up data concentration computer  121  data parameters related to the metering process, and managing data forwarder connectivity related to meters. Setup of all new accounts related to meters, data finders and data center network is carried out from host computer  127 . Data acquired from the data concentrator computer  121  is uploaded to data center network  129  by host computer  127 . Host computer  127  is an active part of data center  129  but is dedicated to interacting with data concentrator computer  121 .  
         [0045]     The data center  129  manages the accumulated database of metered data collected from all meter interface units  102 ,  103 ,  104  and also provides various services based on the data to utilities, end customer, power companies, and maintenance companies etc.  
         [0046]     The invention has been described in terms of embodiments of the invention. It will be apparent to those skilled in the art that various changes and modifications may be made to the embodiments shown and described without departing from either the spirit or scope of the invention. It is intended that the invention include all such changes and modifications. It is further intended that the invention not be limited to the illustrative embodiments shown and/or described. It is intended that the invention be limited only by the scope of the claims appended hereto.