System for achieving optimal steady state in power distribution networks

• US 5,734,586 A
• Filed: 05/05/1995
• Issued: 03/31/1998
• Est. Priority Date: 05/05/1995
• Status: Expired due to Fees

• Current Assignee: Cornell Research Foundation Incorporated (Cornell University)
• Original Assignee: Cornell Research Foundation Incorporated (Cornell University)
• Inventors: Wang, Jin-Cheng, Chiang, Hsiao-Dong
• Primary Examiner(s): Cosimano, Edward R.
• Application Number:
  US08/436,036
• Time in Patent Office: 1,061 Days
• Field of Search: 307/31, 307/35, 307/38, 307/39, 323/209, 340/825.06, 364/148, 364/492, 364/493, 364/494
• US Class Current: 700/286
• CPC Class Codes: H02J 3/16 by adjustment of reactive power
• CPC Class Codes: Y02E 40/30 Reactive power compensation

Abstract

The present invention features a direct, closed-loop method for controlling an unbalanced, power-distribution network having a great number of nodes, branches and laterals, as well as multiphase loads. The network has a radial structure. One or more formulae are first derived for a power-distribution network. The formulae may be an explicit loss formula, a voltage formula, a line flow formula or any combination thereof. Network flow programming techniques which incorporate the formulae are then developed to directly achieve steady state. Finally, the control steps are performed on the power-distribution network in real time to control its operation. The control steps may include placing a capacitor, regulator or switch at a specific position in the network and/or reconfiguring the network in some other manner.

Claims

1. A closed-form method for controlling an unbalanced, power-distribution network, comprising:

a) deriving a formula, including a fundamental, explicit loss formula for a predetermined power-distribution network;

b) applying network flow programming techniques, incorporating said formula, directly to said power-distribution network in order to determine control steps necessary to achieve optimal, steady state therefor;

c) estimating the effect of said control steps on said power-distribution network prior to application thereof; and

d) performing said control steps on said power-distribution network in real time so as to control operation thereof.

2. The closed-form method for controlling an unbalanced, power-distribution network in accordance with claim 1, wherein performing said control steps comprises reconfiguring said power-distribution network.

3. The closed-form method for controlling an unbalanced, power-distribution network in accordance with claim 1, wherein performing said control steps comprises placing a predetermined capacitor at a predetermined position in said power-distribution network, said placement and position of said capacitor being dependent upon a solution of said explicit loss formula.

4. The closed-form method for controlling an unbalanced, power-distribution network in accordance with claim 1, wherein said formula further comprises a voltage formula.

5. The closed-form method for controlling an unbalanced, power-distribution network in accordance with claim 4, wherein said formula further comprises a line flow formula.

6. The closed-form method for controlling an unbalanced, power-distribution network in accordance with claim 1, wherein said power distribution network comprises a plurality of nodes, branches and laterals.

7. The closed-form method for controlling an unbalanced, power-distribution network in accordance with claim 6, wherein said power-distribution network comprises a radial network structure.

8. The closed-form method for controlling an unbalanced, power-distribution network in accordance with claim 7, wherein said power-distribution network comprises multiphase loads.

9. The closed-form method for controlling an unbalanced, power-distribution network in accordance with claim 8, wherein said power-distribution network comprises multiphase shunt elements.

10. The closed-form method for controlling an unbalanced, power-distribution network in accordance with claim 9, wherein said power-distribution network comprises transformers.

11. A closed-form method for controlling an unbalanced, power-distribution network, comprising:

a) deriving a plurality of formulae, including a fundamental, explicit loss formula, for a predetermined power-distribution network;

b) applying network flow programming techniques, incorporating said formulae, directly to said power-distribution network in order to determine control steps necessary to achieve optimal, steady state therefor;

c) estimating the effect of said control steps on said power-distribution network prior to application thereof; and

d) performing said control steps on said power-distribution network in real time so as to control operation thereof.

12. The closed-form method for controlling an unbalanced, power-distribution network in accordance with claim 11, wherein said formulae further comprise:

a) a voltage formula; and

b) a line flow formula.

13. The closed-form method for controlling an unbalanced, power-distribution network in accordance with claim 12, wherein performing said control steps comprises placing a predetermined capacitor at a predetermined position in said power-distribution network, said placement and position of said capacitor being dependent upon a solution of said explicit loss formula.

14. The closed-form method for controlling an unbalanced, power-distribution network in accordance with claim 12, wherein performing said control steps comprises reconfiguring said power-distribution network.

15. The closed-form method for controlling an unbalanced, power-distribution network in accordance with claim 13, wherein said power-distribution network comprises a plurality of nodes, branches and laterals.

16. The closed-form method for controlling an unbalanced, power-distribution network in accordance with claim 15, wherein said power-distribution network comprises a radial network structure.

17. The closed-form method for controlling an unbalanced, power-distribution network in accordance with claim 16, wherein said power distribution network comprises multiphase loads.

18. The closed-form method for controlling an unbalanced, power-distribution network in accordance with claim 17, wherein performing said control steps comprises placing a predetermined capacitor at a predetermined position in said power-distribution network, said placement and position of said capacitor being dependent upon a solution of said explicit loss formula.