Stability distinguishing method of wide-area power system under influence of section variable-time delay

A technology of power system and discrimination method, applied in the field of power system, can solve the problems of reducing conservatism and inaccurate model description.

Active Publication Date: 2018-05-29
HENAN POLYTECHNIC UNIV
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Problems solved by technology

Although the above literature has reduced the conservatism of the time-delay power system stability criterion to a certain extent, there are inaccurate model descriptions, the construction of the L-K functional is too simple, and the method used in the analysis of functional derivatives can reduce the conservatism. has certain limitations and other shortcomings, resulting in a certain degree of conservatism in the obtained stability criterion

Method used

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  • Stability distinguishing method of wide-area power system under influence of section variable-time delay
  • Stability distinguishing method of wide-area power system under influence of section variable-time delay
  • Stability distinguishing method of wide-area power system under influence of section variable-time delay

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Embodiment

[0129] A method for judging the stability of a wide-area power system under the influence of interval-variable time-delays, comprising the following steps:

[0130] Step1. Establish a time-delay power system function model including a wide-area control loop:

[0131]

[0132] Where: x(t)∈R n is the state variable of the power system, x(t-h(t)) is the state variable after time delay, A, A 1 is the system matrix, is a continuous initial phasor function on [-h, 0]; the delay h(t) satisfies:

[0133] 0≤h(t)≤h

[0134]

[0135] Among them, the constant h>0 is the upper bound of the time delay of the system; the constant μ 1 , μ 2 are the upper and lower bounds of the delay derivative.

[0136] When there is a disturbance in the system, the system (1) becomes as follows:

[0137]

[0138] Suppose: [ΔA, ΔA 1 ] = HF 0 [E a ,E b ], ΔA, ΔA 1 is the disturbance term of the system, H, E a ,E b is a constant matrix of known dimension, F 0 is a changing matrix that ...

example 1

[0236] Example 1: Consider the time-varying delay system (1), where:

[0237]

[0238] when h 1 =0, μ=0.5, according to the conclusion in literature [11], the upper bound of the time lag obtained is 2.42, and the upper bound of the time lag obtained by the method of the present invention is 2.63. In addition, Table 1 gives in μ(μ=-μ 1 =μ 2 ) takes different values, the maximum time-delay upper bound to ensure system stability is obtained by using different methods. It can be seen that, using the theorem of the present invention, when μ=0, the upper bound of the time delay is 6.0594; when μ=0.1, the upper bound of the time delay is 4.7261; when μ=0.5, the upper bound of the time delay is 2.6317, and μ=0.8 When , the upper bound of the time delay is 2.2539, which is higher than the maximum time delay value obtained by using the method in literature [18, 24, 25].

[0239] Such as figure 1 As shown, the stable operating regions of the system obtained by using different met...

example 2

[0242] Example 2: Consider the time-varying delay system (1), where:

[0243]

[0244] As shown in Table 2, when μ is 0.1, 0.2, 0.5, and 0.8 respectively, the upper bounds of the maximum time lag given by different methods.

[0245] Table 2 The maximum time lag at different μ values

[0246] mu

[0247] Such as figure 2 As shown, the stable regions of different systems are given. It is easy to see that compared with literature [20, 24, 25], the theorem of the present invention reduces the degree of conservatism of the system stability criterion and effectively expands the stable operation area of ​​the system.

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Abstract

The invention discloses a stability distinguishing method of a wide-area power system under influence of section variable-time delay. According to the stability distinguishing method, a novel augmentation vector and Lyapunov-Krasovskii functional construction method is proposed on the basis of building a wide-area section variable-time delay power system model with regard to serious influence of atime delay phenomenon on stable running of the wide-area power system; an error generated during the resolving process is reduced by employing methods of time delay partition, Wirtinger integral inequality, Free-matrix-based integral inequality and convex combination during resolving of a functional derivative to obtain a stability criterion with relatively low conservation property, and the stable running region of the system is expanded; and finally, compared with an existing method, the method has the advantage that the stable running region of the system is expanded by typical simulationanalysis of a second-order system, a single-machine infinite system and a four-machine eleven-node system.

Description

technical field [0001] The invention relates to the technical field of power systems, in particular to a method for judging the stability of a wide-area power system under the influence of interval variable time delays. Background technique [0002] With the development of our society, the scale of the modern power system and the scope of grid interconnection continue to expand. While improving the economic benefits of grid operation, its dynamic process has become more and more complicated. The traditional local control method has been unable to meet today's large-scale The control requirements for the safe and stable operation of the power grid. In recent years, the rapid development of wide-area measurement technology (WAMS) based on phasor measurement unit (PMU) has been widely used in power systems, which has promoted the development of modern global control of power systems. [1-3] . In the wide-area environment, when the overall monitoring and control of the power sy...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02J3/00
CPCH02J3/00H02J2203/20
Inventor 钱伟王晨晨王俊峰李冰锋黄凯征
Owner HENAN POLYTECHNIC UNIV
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