System reliability assessment tool

• US 6,321,187 B1
• Filed: 12/22/1998
• Issued: 11/20/2001
• Est. Priority Date: 12/22/1998
• Status: Expired due to Fees

• Current Assignee: Sundstrand Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Original Assignee: Hamilton Sundstrand Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Inventors: Henderson, Eric A., Squier, Steven E.
• Primary Examiner(s): Teska, Kevin J.
• Assistant Examiner(s): JONES, HUGH M
• Application Number:
  US09/218,708
• Time in Patent Office: 1,064 Days
• Field of Search: 703/18, 703/17, 703/13
• US Class Current: 703/18
• CPC Class Codes: H02J 2203/20 Simulating, e g planning, reliability check, modelling or computer assisted design [CAD]
• CPC Class Codes: H02J 3/00 Circuit arrangements for ac mains or ac distribution networks
• CPC Class Codes: Y02E 60/00 Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
• CPC Class Codes: Y04S 40/20 Information technology specific aspects, e.g. CAD, simulation, modelling, system security

Abstract

A method for assessing the reliability of an electrical power distribution system begins with identifying each element of the electrical power distribution system, and establishing characteristic data for each of these elements. The characteristic data at least identifies one operating characteristic of the element and further identifies interconnections of that element to other elements in the system. Next, at least one “minimum cut” is determined separating a first system element from a second system element, e.g., a power source from a load. The minimum cut is at least based upon the interconnection data. At least one third element is then identified, located on the minimum cut, and the reliability may then be assessed by evaluating the characteristic data of the at least one third element.

Claims

1. A method for assessing the operational reliability of an electrical power distribution system comprising the steps of:

identifying each element of the electrical power distribution system;

for each element, establishing characteristic data, the characteristic data identifying at least one operating characteristic of the element, and interconnection data, the interconnection data identifying interconnections of the element to at least one other element of the electrical power distribution system;

using the identification data to determine all possible paths within the electrical power distribution system interconnecting the element to the at least one other element;

determining from the all possible paths valid paths interconnecting the element and the at least one other element, wherein a valid path terminates at the at least one other element, is not a redundant path, does not violate permitted flow directions and does not include other active power sources or load elements;

determining from the valid paths at least one minimum cut from a first element of the electrical power distribution system to a second element of the electrical power distribution system based upon the interconnection data;

identifying at least a third element of the electrical power distribution system on the minimum cut;

assessing reliability of the minimum cut based at least upon the characteristic data associated with the third element; and

assessing the operational reliability of the electrical power distribution system based at least upon the reliability of the minimum cut.

2. The method of claim 1, further comprising the steps of:

identifying a plurality of elements on the minimum cut; and

assessing reliability of the minimum cut based at least upon the characteristic data associated with each of the plurality of elements.

3. The method of claim 1, the first element comprising a power source element and the second element comprising a load element.

4. The method of claim 1, further comprising the steps of:

for the first element determining a group of paths including all possible paths extending from the first element, and

selecting for analysis only paths connecting the first element to the second element.

5. The method of claim 1, further comprising the steps of:

determining a plurality of minimum cuts from the first element to the second element,

ranking the minimum cuts based upon a number of elements located on each of the plurality of minimum cuts.

6. The method of claim 5, further comprising the step of eliminating from analysis minimum cuts including more than a predetermined number of elements.

7. The method of claim 5, further comprising the step of selecting a level of minimum cuts for analysis based upon a system architecture.

8. The method of claim 5, further comprising the step of eliminating from analysis minimum cuts including a subset of minimum cut including fewer elements.

9. The method of claim 1, further comprising the step of identifying a sensitivity of the electrical power distribution system to at least one system element.

10. The method of claim 9, wherein the step of identifying a sensitivity comprises the steps of:

individually for each element modifying in a predetermined manner an aspect of the characteristic data and reassessing system reliability utilizing the modified characteristic data; and

ranking the elements based upon results of the system reliability assessment using the modified characteristic data.

11. The method of claim 9, wherein the step of modifying in a predetermined manner an aspect of the characteristic data comprises increasing a failure rate of the element a predetermined percentage amount.

12. A system reliability assessment tool comprising:

a processor coupled to a user interface and to a memory,

the memory including a data structure containing system data representing a plurality of elements and containing for each of the plurality of elements characteristic data and interconnection data, the memory further including an analysis algorithm;

the analysis algorithm including structure for;

i) using the interconnection data to determine all possible paths within the electrical power distribution system interconnecting a first element to at least one other element;

ii) determining from the all possible paths valid paths interconnecting the element and the at least one other element, wherein a valid path terminates at the at least one other element, is not a redundant path, does not violate permitted flow directions and does not include other active power sources or load elements;

iii) determining at least one minimum cut from the valid paths;

iv) identifying at least a third element of the plurality of elements on the minimum cut;

v) assessing reliability of the minimum cut based at least upon the characteristic data associated with the third element; and

vi) assessing system reliability based at least upon the reliability of the minimum cut; and

the processor operable upon the system data in accordance with the analysis algorithm to provide an indication representing a reliability of the system.

13. The system reliability assessment tool of claim 12, wherein the analysis algorithm further comprises structure for:

i) individually for each of the plurality of elements modifying in a predetermined manner an aspect of the characteristic data and reassessing system reliability utilizing the modified characteristic data; and

ii) ranking the plurality of elements based upon a result of the system reliability assessment using the modified characteristic data; and

the processor being further operable upon the system data to rank the plurality of system elements to provide an indication of relative contribution to system reliability of each of the plurality of elements.

14. The system reliability assessment tool of claim 12, wherein the characteristic data comprises at least one reliability data selected from the group of data comprising:

a mean time to failure, a failure probability, a number of failure modes and a type of failure mode.

15. The system reliability assessment tool of claim 12, wherein the interconnection data defines a relationship between the first element and at least one additional system element.

16. The system reliability assessment tool of claim 12, wherein a minimum cut comprises a set of interconnected system elements which isolate a power source element from a load element and in which no subset of the set will cause a system failure.

17. The system reliability assessment tool of claim 12, wherein the user interface includes a graphic display of the system data.

18. The system reliability assessment tool of claim 12, further comprising a system data manipulation tool.

19. The system reliability assessment tool of claim 12 integrated into a computer aided engineering tool.

20. The system reliability assessment tool of claim 12 implemented in a Windows operating system environment.