Region-based security evaluation method for the electric power distribution system

Patent metadata

Field	Value
Publication number	US-9310406-B2
Application number	US-201213812518-A
Country	US
Kind code	B2
Filing date	Jul 24, 2012
Priority date	Sep 22, 2011
Publication date	Apr 12, 2016
Grant date	Apr 12, 2016

Abstract

The invention discloses a region-based security evaluation method for the distribution system, which belongs to the eld of electric power distribution system operation. The method contains the following steps: (1) acquiring distribution system security region and security boundaries according to substation transformer capacity of the distribution system and link relationships among the substation transformers ( 101 ); (2) acquiring the distance between operating point and the security boundaries (IO 2 ); (3) judging whether the operating point is within the distribution system security region according to the distance between the operating point and security boundaries ( 103 ); if yes, performing step (4), otherwise, performing step (5); (4) acquiring the load shortage or excess L,- of a link unit (I 04 ); (5) adjusting the load of the substation transformers until the operating point comes back to the distribution system security region, then performing step (4) (IO 5 ). The method provides more information than traditional N-I simulation in distribution system security assessment; and reduces calculation, increases the operating speed and satisfies the requirement of real-time and on-line operation.

First claim

What is claimed is:

1. A method for evaluating N−1 region-based security for an electric power distribution system which carries a load and comprises a plurality of substations each of which comprises a substation transformer, comprising steps of:
(1) calculating an N−1 security region of the distribution system and boundaries of the security region from the capacity of the substation transformers and link relationships between the substation transformers;
(2) calculating the distance between an operating point and the N−1 security boundaries;
(3) determining whether the operating point is within the N−1 security region based on the distance between the operating point and security boundaries, and performing step (4) if the operating point is within the security region or performing step (5) if the operating point is not within the security region;
(4) calculating the amount of load shortage or excess of a link unit to complete an evaluation procedure; and
(5) if deemed necessary based on the determination in step (3), adjusting the load of the substation transformers until the operating point falls within the N−1 security region, and then performing step (4);
wherein the N−1 region-based security is a state in which the load is successfully relocated when any one substation in the system fails and the load at other substation is constrained from overloading.

2. The method of claim 1 , wherein the security region is generally expressed as:
Ω DSSR ={T|g ( T )≦0}  (1)

where T is an operating point and g(T) is a set of inequality constraint to T.

3. The method of claim 2 , wherein the security region is generally expressed as:

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Assignees

• Xiao Jun
• Wang Chengshan
• Yu Yixin
• Gu Wenzhuo
• Univ Tianjin

Inventors

• Xiao Jun
• Wang Chengshan
• Yu Yixin
• Gu Wenzhuo

Classifications

• H02J2103/30

  Simulating, planning, modelling, reliability check or computer assisted design [CAD] of electric power networks · CPC title

• H02J3/12 Primary

  Arrangements for adjusting voltage in AC networks by changing a characteristic of the network load · CPC title

• G06Q50/06

  Energy or water supply · CPC title

• G01R21/06

  by measuring current and voltage (G01R21/08 - G01R21/133 take precedence) · CPC title

• G01R21/133 Primary

  by using digital technique · CPC title