Meter collar with interface for connecting on-site power source, and the interface itself

• US 6,188,145 B1
• Filed: 06/04/1999
• Issued: 02/13/2001
• Est. Priority Date: 06/11/1998
• Status: Expired due to Term

• Current Assignee: Electric Power Research Institute Incorporated
• Original Assignee: Potomac Capital Investment Corp. (Exelon Corporation)
• Inventors: Stewart, Robert S.
• Primary Examiner(s): Ballato, Josie
• Assistant Examiner(s): DeBeradinis, Robert L
• Application Number:
  US09/325,735
• Time in Patent Office: 620 Days
• Field of Search: 307/43, 307/64, 307/65, 307/70, 307/149, 307/112, 307/150, 307/125
• US Class Current: 307/125
• CPC Class Codes: G01R 11/02 Constructional details
• CPC Class Codes: H02J 3/38 Arrangements for parallely feeding a single network by two or more generators, converters or transformers
• CPC Class Codes: H02J 3/388 Islanding, i.e. disconnection of local power supply from the network
• CPC Class Codes: H02J 7/007 Regulation of charging or discharging current or voltage
• CPC Class Codes: H02J 9/06 with automatic change-over , e.g. UPS systems

Abstract

An interface circuit permits a customer who receives two-phase service from an electrical utility company to use power from an on-site source instead of or in addition to the utility company'"'"'s power. Several embodiments are disclosed, in some of which the interface circuit automatically disconnects the utility company'"'"'s power lines if the utility'"'"'s power is lost and connects the on-site power source. The interface circuit may be installed in whole or in part in a meter collar which fits between an electric meter and the meter socket box that the meter would otherwise plug into.

Claims

1. A meter collar for use between a watt-hour meter and a socket having utility-side contacts which are connected to power lines of a utility and having customer-side contacts which are connected to at least one load, comprising:

a housing having first contacts for connection to the utility-side contacts of the socket and second contacts for connection to the customer-side contacts of the socket, the housing additionally having further contacts for connection with the meter; and

an interface circuit having conductors which connect the first contacts to the meter and having means for selectively connecting the second contacts to either the meter or to an on-site power source, the means for selectively connecting comprising primary detection means for detecting whether the on-site power source is supplying power and a secondary detection means, connected to the primary detection means, for detecting whether the power lines are supplying power if the primary detection means does not detect power supplied by the on-site power source.

2. The meter collar of claim 1, wherein the means for selectively connecting further comprises switches connected between the meter and the second contacts, and means for opening and closing the switches, the means for opening and closing being connected to the primary and secondary detection means.

3. The meter collar of claim 2, wherein the switches are mechanically coupled to the means for opening and closing, the switches together with the means for opening and closing comprising a latching switch assembly.

4. The meter collar of claim 2, wherein the means for selectively connecting further comprises switchover means for selectively connecting the on-site power source to the second contacts, the switchover means being connected to the primary and secondary connection means.

5. The meter collar of claim 4, wherein the switchover means comprises a switchover relay having a solenoid and a pair of switches, and an input circuit connected to the solenoid of the switchover relay, the input circuit including a transformer and a rectifying and smoothing circuit, the switches of the switchover relay being connected between the on-site power source and the second contacts.

6. The meter collar of claim 5, wherein the primary detection means comprises a primary detection relay having a solenoid, and an input circuit connected to the solenoid of the primary detection relay, the input circuit that is connected to the solenoid of the primary detection relay including a transformer and a rectifying and smoothing circuit.

7. The meter collar of claim 6, wherein the primary detection relay includes a pair of switches, one of which connected between the on-site power source and the means for opening and closing the switches that are connected between the meter and the second contacts, and the other of which is connected between the secondary detection means and one of the conductors that connect the first contacts to the meter.

8. The meter collar of claim 6, wherein the secondary detection means comprises a secondary detection relay having a solenoid, and an input circuit connected to the solenoid of the secondary detection relay, the input circuit that is connected to the solenoid of the secondary detection relay including a transformer and a rectifying and smoothing circuit.

9. The meter collar of claim 8, wherein the secondary detection relay includes a pair of switches, one of which is connected between the primary detection relay and the means for opening and closing the switches that are connected between the meter and the first contacts, and the other of which is connected between means for opening and closing the switches that are connected between the meter and the first contacts and the input circuit that is connected to the solenoid of the primary detection relay.

10. The meter collar of claim 1, wherein the primary detection means comprises a primary detection relay and an input circuit connected to the primary detection relay, and a secondary detection relay and an input circuit that is connected to the secondary detection relay, each input circuit including a respective rectifying and smoothing circuit.

11. The meter collar of claim 1, wherein at least a portion of the interface circuit is disposed inside the housing.

12. An interface method for connecting at least one load to either an on-site power source or to power lines of a utility, comprising the steps of:

(a) detecting whether the on-site power source is supplying power;

(b) opening first switches between the power lines and the at least one load if the on-site power source is supplying power;

(c) after the fist switches have been opened in step (b), closing second switches between the on-site power source and the load;

(d) detecting whether the power lines are supplying power, but only if power is not being supplied by the on-site power source;

(e) opening the second switches if power supplied by the power lines is detected in step (d); and

(f) after the second switches have been opened in step (e), closing the first switches.

13. The method of claim 12, wherein step (b) comprises actuating a primary detection relay and step (e) comprises actuating a secondary detection relay if the primary detection relay is not actuated.

14. The interface method of claim 12, further comprising turning the on-site power source on if the power lines have been supplying power and then stop supplying power.

15. The interface method of claim 12, wherein steps (b) and (f) comprise actuating a latching switch assembly.

16. The interface method of claim 12, wherein step (b) comprises actuating a primary detection relay if the on-site power source is supplying power.

17. The interface method of claim 16, wherein the primary detection relay is an electromechanical relay.

18. The interface method of claim 16, wherein step (e) comprises actuating a secondary detection relay that is interconnected with the primary detection relay, so that both relays cannot be actuated simultaneously.

19. A meter collar for use between a watt-hour meter and a socket having utility-side contacts which are connected to power lines of a utility and having customer-side contacts which are connected to at least one load, the meter collar being coupled to a receptacle for receiving a plug that is connected to an on-site power source, said meter collar comprising:

a housing having first contacts for connection to the utility-side contacts of the socket and second contacts for connection to the customer-side contacts of the socket, the housing additionally having further contacts for connection with the meter;

means for detecting whether the plug is received in the receptacle; and

an interface circuit having conductors which connect the first contacts to the meter, means for connecting the second contacts to the meter if the plug is not received in the receptacle, and means for connecting the second contacts to the receptacle if the plug is received in the receptacle.

20. The meter collar of claim 19, wherein the means for connecting the second contacts to the meter if the plug is not received in the receptacle comprises at least one relay.

21. The meter collar of claim 19, wherein the means for detecting whether the plug is received in the receptacle comprises at least one switch that is mechanically actuated by the plug.

22. A meter collar for use between a watt-hour meter and a socket having utility-side contacts which are connected to power lines of a utility and having customer-side contacts which are connected to at least one load, comprising:

a housing having first contacts for connection to the utility-side contacts of the socket and second contacts for connection to the customer-side contacts of the socket, the housing additionally having further contacts for connection with the meter; and

an interface circuit having conductors which connect the first contacts to the meter and having means for selectively connecting the second contacts to at least one of the meter and an on-site power source, the means for selectively connecting comprising;

means for detecting whether the on-site power source is supplying power, and

means for connecting the on-site power source to the second terminals, regardless of whether the meter is also connected to the second terminals.

23. The meter collar of claim 22, wherein the means for detecting comprises at least one electrical sensor.

24. The meter collar of claim 23, wherein the means for selectively connecting further comprises a microprocessor that receives signals generated by the at least one sensor.

25. The meter collar of claim 24, wherein the means for selectively connecting further comprises means for generating a signal that is supplied to the microprocessor to indicate whether both the meter and the on-site power source are permitted to be connected to the second contacts simultaneously.

26. The meter collar of claim 22, wherein the means for connecting comprises at least one relay.

27. A meter collar for use between a watt-hour meter and a socket having utility-side contacts which are connected to power lines of a utility and having customer-side contacts which are connected to at least one load, a tone generator being connected to the power lines, said meter collar comprising:

a housing having first contacts for connection to the utility-side contacts of the socket and second contacts for connection to the customer-side contacts of the socket, the housing additionally having further contacts for connection with the meter; and

an interface circuit having conductors which connect the first contacts to the meter, a detector for the tone from the generator and means for selectively connecting the second contacts to either the meter if the tone is detected, or to an on-site power source, if the tone is not detected.

28. The meter collar of claim 27, wherein the means for selectively connecting comprises at least one relay.