Linear asymmetric method for examining branch-outage-type steady-state security of AC power networks

Patent metadata

Field	Value
Publication number	US-11366175-B2
Application number	US-201916630135-A
Country	US
Kind code	B2
Filing date	Jan 28, 2019
Priority date	Jan 28, 2019
Publication date	Jun 21, 2022
Grant date	Jun 21, 2022

Abstract

A linear asymmetric method for examining branch-outage-type steady-state security of AC power networks is provided. Two linear expressions of bus injection active and reactive powers in terms of translation voltages and voltage angles of all buses are established. Then a linear asymmetric matrix-equation model for the steady state of the network is built considering the reference bus number. Manipulating this model produces the matrix expression of branch-not-outage-type translation voltages and voltage angles of non-reference buses and the bus impedance matrix with the reference bus discarded. The branch-outage-type translation-voltage increments and voltage-angle increments of non-reference buses are then obtained by the bus impedance matrix and the outage branch using the calculation formula of ordinary inverse of a modified matrix. The examination of the steady-state security of the network is achieved using these increments. The present application provides a fast and accurate method for examining branch-outage-type steady-state security of AC power networks.

First claim

What is claimed is:

1. A linear asymmetric method for examining branch-outage-type steady-state security of an AC power network, comprising the following steps:
establishing two linear expressions of bus injection active and reactive powers of sources and loads in terms of translation voltages and voltage angles of all buses according to bus injection powers of sources and loads and branch admittances in the AC power network;
establishing a linear asymmetric matrix-equation model for the steady-state of the AC power network according to the two linear expressions of bus injection active and reactive powers of sources and loads in terms of translation voltages and voltage angles of all buses and a given reference bus serial number;
obtaining branch-not-outage-type translation voltages and voltage angles of non-reference buses and bus impedance matrix with the reference bus discarded according to the linear asymmetric matrix-equation model for the steady-state of the AC power network by using the ordinary inverse of a matrix;
obtaining branch-outage-type translation-voltage increments and voltage-angle increments of non-reference buses according to the branch-not-outage-type bus impedance matrix with the reference bus discarded and an outage branch by using the calculation formula of the ordinary inverse of a modified matrix; and
examining the steady-state security of the AC power network according to the branch-not-outage-type translation voltages and voltage angles of non-reference buses and the branch-outage-type translation-voltage increments and voltage-angle increments of non-reference buses.

2. The linear asymmetric method according to claim 1 , wherein the step of establishing the two linear expressions of bus injection active and reactive powers of sources and loads in terms of translation voltages and voltage angles of all buses according to bus injection powers of sources and loads and branch admittances in the AC power network comprises:
establishing the two linear expressions of bus injection active and reactive powers of sources and loads in terms of translation voltages and voltage angles of all buses by the following equations:

P
i

=

∑

j
=
1

,

j
≠
i

n

⁢

(

-

θ
i

⁢

b
ij

+

v
i

⁢

g
ij

+

θ
j

⁢

b
ij

-

v
j

⁢

g
ij

)

⁢

⁢

Q
i

=

∑

j
=
1

,

j
≠
i

n

⁢

(

-

θ
i

⁢

g
ij

-

v
i

⁢

b
ij

+

θ
j

⁢

g
ij

+

v
j

⁢

b
ij

)

wherein, both i and j denote serial numbers of buses in the AC power network and belong to the set of continuous natural numbers, namely belong to {1,2, . . . , n}; n denotes the total number of buses in the AC power network; P i and Q i denote the active and reactive powers of the source and load at bus i, respectively, and are referred to collectively as the powers of the source and load at bus i; g ij and b ij denote the conductance and susceptance of branch ij connected between bus i and bus j, respectively, and are referred to collectively as the admittance of branch ij; θ i and θ j denote the voltage angles at bus i and bus j, respectively; and v i and v j denote the translation voltages at bus i and bus j, respectively, and both the v i and v j are per-unit voltages translated by −1.0.

3. The linear asymmetric method according to claim 1 , wherein the step of establishing the linear asymmetric matrix-equation model for the steady-state of the AC power network according to the two linear expressions of bus injection active and reactive powers of sources and loads in terms of translation voltages and voltage angles of all buses and a given reference bus serial number comprises:
establishing the linear asymmetric matrix-equation model for the steady-state of the AC power network by the following

Assignees

• Univ Shenzhen

Inventors

• Peng Jianchun
• Jiang Hui
• Yin Jian

Classifications

• H02J2103/30

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

• H02J13/12

  Monitoring network conditions, e.g. electrical magnitudes or operational status · CPC title

• H02J3/0012 Primary

  characterised by the contingency detection means in AC networks, e.g. using phasor measurement units [PMU], synchrophasors or contingency analysis · CPC title

• G01R31/42 Primary

  AC power supplies · CPC title

• H02J3/04

  Arrangements for connecting networks of the same frequency but supplied from different sources · CPC title