Electricity market-oriented dc-segmentation design and optimal scheduling for electrical power transmission

• US 7,620,482 B2
• Filed: 03/05/2004
• Issued: 11/17/2009
• Est. Priority Date: 03/05/2003
• Status: Active Grant

• Current Assignee: DC Interconnect Inc.
• Original Assignee: DC Interconnect Inc.
• Inventors: Epp, H. D. Kenneth, El-Gasseir, Mohamed M.
• Primary Examiner(s): Bahta; Kidest
• Application Number:
  US10/547,867
• Publication Number:
  US 20070067065A1
• Time in Patent Office: 2,083 Days
• Field of Search: 700/286, 700/291, 700/297, 209/2, 705/36, 705/412
• US Class Current: 700/286
• CPC Class Codes: G06Q 10/00 Administration; Management
• CPC Class Codes: G06Q 50/06 Energy or water supply
• CPC Class Codes: H02J 3/001 Methods to deal with contingencies, e.g. abnormalities, faults or failures
• CPC Class Codes: H02J 3/008 involving trading of energy or energy transmission rights
• CPC Class Codes: H02J 3/06 Controlling transfer of power between connected networks; Controlling sharing of load between connected networks
• CPC Class Codes: H02J 3/34 Arrangements for transfer of electric power between networks of substantially different frequency
• CPC Class Codes: H02J 3/36 Arrangements for transfer of electric power between ac networks via a high-tension dc link
• CPC Class Codes: Y02B 70/3225 Demand response systems, e.g. load shedding, peak shaving
• CPC Class Codes: Y02E 40/70 Smart grids as climate change mitigation technology in the energy generation sector
• CPC Class Codes: Y02E 60/60 Arrangements for transfer of electric power between AC networks or generators via a high voltage DC link [HVCD]
• 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 20/222 Demand response systems, e.g. load shedding, peak shaving
• CPC Class Codes: Y04S 50/10 Energy trading, including energy flowing from end-user application to grid

Abstract

A method of segmenting a power distribution network which comprises a plurality of AC power generating stations synchronously interconnected by AC power transmission paths is disclosed. The stations operate within associated market sectors and are subject to associated market rules. The method includes identifying all transmission paths which extend between differing ones of the sectors and, in each of said transmission paths so identified, segmenting the path by inserting a controllable DC link at a selected location in the path. Each of the sectors is then operated asynchronously. Power flow and counter-flow between the sectors is controlled by controlling the DC links. As well there is disclosed a power transmission network which comprises a plurality of AC power generating stations operable within associated market sectors subject to associated market rules; power transmission paths interconnecting the stations, at least some of the paths extending between differing ones of the sectors; and wherein each of the paths which extend between differing ones of the sectors includes a controllable DC link in the path for desynchronizing the differing sectors; and, control means operatively connectable to each of the DC links for controlling power flow between the differing sectors.

Claims

1. A method of segmenting a pre-existing multi-regional alternating current (ac) grid, said grid comprising a plurality of ac power generating stations synchronously interconnected by ac power transmission paths, said stations operable within associated market sectors subject to associated market rules, said method comprising the steps of:

(a) identifying all of those ones of said ac transmission paths which extend between differing ones of said market sectors;

(b) in each of said ac transmission paths so identified, segmenting the path by inserting a controllable direct current (dc) link at a selected location in the identified path, thereby defining a plurality of ac sectors;

(c) operating each of said ac sectors asynchronously; and

,

(d) controlling power flow between said ac sectors by controlling the operation of said dc links.

2. A method as defined in claim 1, further comprising splitting at least one of said ac sectors into two or more subsectors operable asynchronously of each other.

3. A method as defined in claim 1, wherein said step of controlling power flow comprises identifying an optimal route depending on demand for delivering electric energy from one of said market sectors to another one of said market sectors, said route comprising at least one of said dc links.

4. A method of segmenting a pre-existing multi-regional alternating current (ac) grid, said grid comprising a plurality of ac power generating stations synchronously interconnected by ac power transmission paths, said stations operating within associated market sectors subject to associated market rules, said method comprising the steps of:

(a) identifying locations in all of those ones of said ac transmission paths at which a controllable direct current (dc) link can be inserted to substantially reduce the likelihood of the cascading of a grid outage in one of said sectors to another one of said sectors;

(b) selecting a least-cost plurality of said dc links and associated locations to achieve a desired level of prevention of cascading outages;

(c) at each location so selected, segmenting the associated ac transmission path by inserting the associated dc link at the selected location; and

,

(d) controlling power flow between said sectors by controlling the operation of said selected dc links.

5. A modified electric energy transmission network, said network before modification comprising a pre-existing multi-regional alternating current (ac) grid comprising a plurality of ac power generating stations synchronously interconnected by ac power transmission paths, said stations operable within associated market sectors subject to associated market rules, said network after modification comprising:

(a) said plurality of ac power generating stations operable within said associated market sectors subject to said associated market rules;

(b) electric energy transmission paths interconnecting said stations, at least some of said paths extending between differing ones of said sectors, and wherein each of said paths which extend between differing ones of said sectors includes a controllable direct current (dc) link in the path for desynchronizing said differing sectors, each of said dc links being inserted at a location segmenting a pre-existing ac power transmission path into a transmission path comprising the dc link and ac power transmission paths on opposed sides of said link; and

,

(c) control means operatively connectable to each of said dc links for controlling power flow between said differing sectors by controlling the operation of said dc links.

6. A network of direct current (dc) links and control means wherein:

(a) said network is for transmitting electric power between asynchronously operated alternating current (ac) sectors subject to associated market rules, each sector resulting from the segmentation of a pre-existing multi-regional ac grid by said dc links, said grid before segmentation comprising a plurality of ac power generating stations synchronously interconnected by ac power transmission paths; and

,

(b) said control means is operatively connectable to each of said dc links for controlling power flow between said differing sectors by controlling the operation of said dc links.

7. A network and control means as defined in claim 6, wherein at least some of said dc links comprise a pair of back-to-back ac-to-dc and dc-to-ac converters.

8. A network and control means as defined in claim 7, wherein at least one of said dc links comprises a dc conductor terminating at opposed ends of said conductor with an ac-to-dc converter and a dc-to-ac converter.

9. A network and control means as defined in claim 6, 7 or 8, further comprising a network operating center operatively connected to each one of said dc links, said center for receiving data corresponding to scheduled demand for power transmission services between pairs of said sectors, for analyzing such data, and for determining command instructions for the routing of power through said network depending upon the result of such analysis.

10. A network and control means as defined in claim 9, each of said ac sectors including an associated sector control center, said network further comprising a communications network for communicating:

(a) requests for inter-sector transmission service schedules from said sector control centers to said network operating center;

(b) availability of transfer capability at individual ac links to said network operating center; and

,

(c) preliminary and final feasible transmission service schedules from said network operating center to said sector control centers.