Systems and methods for convex relaxations and linear approximations for optimal power flow in multiphase radial networks

• US 10,198,018 B2
• Filed: 05/28/2015
• Issued: 02/05/2019
• Est. Priority Date: 05/28/2014
• Status: Active Grant

• Current Assignee: California Institute of Technology
• Original Assignee: California Institute of Technology
• Inventors: Gan, Lingwen, Low, Steven H.
• Primary Examiner(s): Hartman, Jr., Ronald D
• Application Number:
  US14/724,757
• Publication Number:
  US 20150346753A1
• Time in Patent Office: 1,349 Days
• CPC Class Codes: G05B 15/02 electric
• CPC Class Codes: G05F 1/66 Regulating electric power
• CPC Class Codes: G06Q 50/06 Energy or water supply
• CPC Class Codes: H02J 13/00002 characterised by monitoring
• CPC Class Codes: H02J 13/00034 the elements or equipment being or involving an electric power substation
• CPC Class Codes: H02J 2203/20 Simulating, e g planning, reliability check, modelling or computer assisted design [CAD]
• CPC Class Codes: H02J 3/0073 for providing alternative feeding paths between load and source when the main path fails, e.g. transformers, busbars
• CPC Class Codes: Y02B 90/20 Smart grids as enabling technology in buildings sector smart grids supporting the management or operation of end-user stationary applications in general, or like technologies with no associated climate change mitigation effect Y04S20/00
• CPC Class Codes: Y02E 40/70 Smart grids as climate change mitigation technology in the energy generation sector
• CPC Class Codes: Y02E 60/00 Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
• CPC Class Codes: Y04S 10/30 State monitoring, e.g. fault, temperature monitoring, insulator monitoring, corona discharge
• CPC Class Codes: Y04S 10/50 Systems or methods supporting the power network operation or management, involving a certain degree of interaction with the load-side end user applications
• CPC Class Codes: Y04S 10/52 Outage or fault management, e.g. fault detection or location
• CPC Class Codes: Y04S 20/00 Management or operation of end-user stationary applications or the last stages of power distribution; Controlling, monitoring or operating thereof
• CPC Class Codes: Y04S 40/20 Information technology specific aspects, e.g. CAD, simulation, modelling, system security

Abstract

Centralized node controllers in accordance with embodiments of the invention enable linear approximation of optimal power flow. One embodiment includes a centralized node controller including: a network interface, a processor, and a memory containing: a centralized power control application a network topology, where the network is multiphase unbalanced and comprises a plurality of connected nodes; wherein the processor is configured by the centralized controller application to: request node operating parameters from the plurality of connected nodes; calculate network operating parameters using a linear approximation of optimal power flow and the node operating parameters from the plurality of connected nodes; send network operating parameters to the plurality of connected nodes.

Claims

1. A centralized node controller, comprising:

a network interface;

a processor; and

a memory, containing;

a centralized power control application;

a network topology, where the network is multiphase unbalanced and comprises a plurality of connected noes;

wherein the processor is configured by the centralized controller application to;

request node operating parameters from the plurality of connected nodes;

calculate network operating parameters using a linear approximation of optimal power flow and the node operating parameters from the plurality of connected nodes; and

send network operating parameters to the plurality of connected nodes, wherein the linear approximation of optimal power flow is evaluated using the following expressions;

2. The centralized node controller of claim 1, wherein the linear approximation of optimal power flow further comprises the assumption of small line losses.

3. The centralized node controller of claim 1, wherein the linear approximation of optimal power flow further comprises the assumption of nearly balanced voltage.

4. The centralized node controller of claim 1, wherein the network topology further comprises a radial network.

5. The centralized node controller of claim 1, wherein the network topology further comprises a network on Kirchoffs laws.

6. The centralized node controller of claim 1, wherein the network topology further comprises a bus injection model (BIM) network model.

7. The centralized node controller of claim 1, wherein the network topology comprises a branch flow model (BFM) network model.

8. The centralized node controller of claim 1, wherein node operating parameters include power flow and voltage.

9. The centralized node controller of claim 1, wherein each node in the plurality of connected nodes comprises a node controller, wherein the node controller comprises:

a node network interface;

a node processor;

a node memory containing;

a node controller application; and

a plurality of individual node operating parameters describing the operating parameters of a node in the plurality of connected nodes;

wherein the node processor is configured by the node controller application to;

send individual node operating parameters to the centralized node controller;

receive network operating parameters from the centralized node controller;

calculate updated individual node operating parameters using network operating parameters; and

adjust the individual node operating parameters.

10. A centralized node controller, comprising:

a network interface;

a processor; and

a memory, containing;

a centralized power control application;

a network topology, where the network is multiphase unbalanced and comprises a plurality of connected noes;

wherein the processor is configured by the centralized controller application to;

request node operating parameters from the plurality of connected nodes;

calculate network operating parameters using a linear approximation of optimal power flow and the node operating parameters from the plurality of connected nodes; and

send network operating parameters to the plurality of connected nodes, wherein the network topology is simplified using a convex relaxation, wherein the convex relaxation is semidefinite programming (SDP) relaxation, where in the SDP relaxation exploits a radial network topology, wherein the network topology further comprises a bus injection model (BIM) network topology, and where in the SDP relaxation exploiting a radial network topology further comprises a BIM-SDP which is evaluated using the following expression;

11. The centralized node controller of claim 10, wherein the BIM-SDP is subject to constraints.

12. The centralized node controller of claim 10, wherein the constraints are evaluated using the following expressions:

13. A centralized node controller, comprising:

a network interface;

a processor; and

a memory, containing;

a centralized power control application;

a network topology, where the network is multiphase unbalanced and comprises a plurality of connected noes;

wherein the processor is configured by the centralized controller application to;

request node operating parameters from the plurality of connected nodes;

calculate network operating parameters using a linear approximation of optimal power flow and the node operating parameters from the plurality of connected nodes; and

send network operating parameters to the plurality of connected nodes, wherein the network topology is simplified using a convex relaxation, wherein the convex relaxation is semidefinite programming (SDP) relaxation, where in the SDP relaxation exploits a radial network topology, wherein the network topology further comprises a branch flow model (BFM) network topology, and wherein the SDP relaxation exploiting a radial network topology further comprises a BFM-SDP which is evaluated using the following expression;

14. The centralized node controller of claim 13, wherein BFM-SDP is subject to constraints.

15. The centralized node controller of claim 14, wherein the constraints are evaluated using the following expressions: