Load management terminal

• US 4,402,059 A
• Filed: 04/09/1981
• Issued: 08/30/1983
• Est. Priority Date: 04/09/1981
• Status: Expired due to Fees

• Current Assignee: ABB Power T&D Limited (ABB Limited)
• Original Assignee: Westinghouse Electric Company LLC (Brookfield Asset Management Incorporated)
• Inventors: Kennon, Jerry M., Phillips, John S.
• Primary Examiner(s): Shaw, Gareth D.
• Assistant Examiner(s): Flyntz, T.
• Application Number:
  US06/252,685
• Time in Patent Office: 873 Days
• Field of Search: 364/200 MS File, 364/900 MS File, 364/492-494
• US Class Current: 713/300
• CPC Class Codes: G01R 21/00 Arrangements for measuring electric power or power factor G01R7/12 takes precedence

Abstract

A load management terminal is utilized as an end device in a utility'"'"'s distribution network communication system. The distribution network carries electrical power as well as communication signals. The load management terminal is comprised of a power line coupling unit for connecting the load management terminal to the power distribution network. A signal receiver and conditioning unit produces a command signal in response to a received communication signal. A solid state memory contains preprogrammed instructions and data. A control logic circuit performs load control functions in response to the preprogrammed instructions, data and the command signal. These load control functions include the opening and closing of load control switches for selectively disconnecting and connecting, respectively, customer loads. A cold load pick-up produces power outage information enabling the load management terminal to provide local, load control functions.

Claims

1. A microprocessor based load management terminal, said load management terminal being a component in a power distribution system for delivering electrical power and carrying information, said load management terminal comprising:

a power line coupling unit connecting said load management terminal to the power distribution system;

a signal receiver and conditioning unit producing a command signal in response to said power line coupling unit;

control logic means performing load management functions in response to said command signal;

a power supply producing supply voltages for said load management terminal;

a plurality of load control switches each selectably connecting a load to said power distribution system in response to said control logic means; and

a cold load pick-up monitoring one of said supply voltages, said cold load pick-up producing an output signal responsive to power outages, said output signal input to said control logic means such that said load is disconnected in response to said cold load pick-up;

said loads being disconnected by said control logic means in response to a said cold load pick-up output signal for a predetermined shed time plus a randomly generated shed time such that said loads are reconnected to the power distribution system at different times.

2. The load management terminal of claim 1 wherein the load is disconnected by said control logic means in response to a said cold load pick-up output signal for a predetermined time in response to a power-outage of at least seventy-five seconds.

3. The load management terminal of claim 1 wherein the cold load pick-up includes a capacitor being charged to a predetermined voltage level in response to one of the supply voltages, a field-effect transistor connected across another of said supply voltages, said transistor being conductive in response to said voltage level of said capacitor, and a Schmitt trigger producing the output signal for disconnecting the load in response to the voltage across said transistor.

4. The load management terminal of claim 1 including means producing a clock signal, and wherein said cold load pick-up comprises a gate and means for producing said output signal, said clock signal producing means and said output signal producing means both being connected to an input of said gate, said gate selectively transmitting said clock signal to said control logic means in the absence of said output signal and transmitting said output signal to said control logic means when said output signal is present at said gate input.

5. The load management terminal of claim 1 including a time of day metering circuit calculating electric energy consumption for a plurality of predetermined rates including a base rate, said time of day metering circuit having an input connected to said cold load pick-up, and wherein said metering circuit calculates electric energy consumption for said base rate upon the receipt of said output signal by said control logic means.