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A time-delay power system stability analysis method and controller for reducing conservatism

A technology of power system and analysis method, applied in the field of wide-area power system analysis, which can solve the problems of inaccurate model description and reduction of conservatism.

Active Publication Date: 2018-12-18
HENAN POLYTECHNIC UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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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, the model description is inaccurate, the construction of the functional is too simple, and the method used in the analysis of the derivative of the functional has the advantage of reducing the conservatism. Certain limitations and other shortcomings, resulting in a certain degree of conservatism in the conclusions obtained

Method used

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  • A time-delay power system stability analysis method and controller for reducing conservatism
  • A time-delay power system stability analysis method and controller for reducing conservatism
  • A time-delay power system stability analysis method and controller for reducing conservatism

Examples

Experimental program
Comparison scheme
Effect test

example 1

[0276] Example 1: Consider an interval variable time delay system, where:

[0277]

[0278] When μ=0.5 and μ=0.9, at the lower bound of the time lag h 1 Given a given situation, use Theorem 1 to find the upper bound of the maximum time delay that guarantees the stable operation of the system, and compare the results of this application with literature [16] and literature [27]. Table 1 gives different time delays. Lower bound h 1 The upper bound of time delay h obtained by different methods 2 . It can be seen from Table 1 that in h 1 When the values ​​are 1, 2, and 3, the upper bound of the maximum allowable time delay obtained by Theorem 1 of this application is larger than the results obtained in [16] and [27], which is less conservative.

[0279] in figure 1 , figure 2 When μ=0.5 and μ=0.9, the stable operation area of ​​the system of this application and literature [16] and [27] are respectively given. It can be seen that, compared with literature [16] and [27], the system ha...

example 2

[0282] Example 2: Use as image 3 The shown 4-machine 11-node system further analyzes the effectiveness of the method adopted in this application in reducing the conservativeness of the conclusion on the stability of the wide-area time-varying time-delay power system.

[0283] According to the method of modal analysis in literature [29], the state matrix A, A of the four-machine power system is obtained 1 They are:

[0284]

[0285] Table 2 lists the upper bound of the time delay obtained by Theorem 1 of 0.571, which is compared with 0.195 in [6], 0.288 in [29], 0.328 in [30], and 0.440 in [18]. The upper bounds of lag are larger than other documents, which shows that the method proposed in this application is effective in reducing the stability of wide-area time-varying time-delay systems. It also proves that the method in this application is effective in multi-machine systems. Sex.

[0286] Table 2 Using different methods to obtain the maximum time lag

[0287] method

example 3

[0288] Example 3: Use as Figure 4 The single-machine infinite bus system shown here verifies the control effect of the controller designed in this application. Refer to the literature [31] for the values ​​of specific parameters of the system.

[0289] Among them, the state matrix A, A of the single-machine infinite power system 1 They are:

[0290]

[0291]

[0292] For the single-machine infinite bus system, Table 3 shows the upper bound of the maximum time delay obtained by different methods. It can be seen that the upper bound of the maximum time delay of the system obtained by theorem 1 of this application is 69.74, which is greater than the literature [17] 65.4 in [15], 61.3 in [18], 65.4 in [18], 65.29 in [14], and 68.1 in [21], verifying that the proposed method reduces the conservativeness of the system stability criterion.

[0293] Table 3 Use different methods to obtain the maximum time lag

[0294] method

[17]

[15]

[18]

[14]

[21]

Theorem 1

h2

65.4

60.9

65.4

65.3

68.1

69.74

[...

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Abstract

The analysis method provided by the invention comprises steps of At first, construct a wide-area power system mathematical model contain interval variable time delay, and then, a new augmented vectorand Lyapunov-Krasovskii Functionals: In the Construction of Lyapunov-Krasovskii functional, a new augmented variable is introduced into V1, the piecewise integral treatment is done in the integral interval of V2, and the triple integral term is introduced in the construction of V4. The above method can further reduce the conservativeness of the stability criterion of the system. In the meantime, what about Lyapunov-Wirtinger integral inequality, Extended integral inequality and convex combination are introduced in the derivative analysis of Krasovskii functional, which reduce the scaling error, reduce the conservatism of the stability results and enlarge the stable operating region of the system. On this basis, a feedback controller is designed. The existence condition of the controller isreduced to the form of strict linear matrix inequalities (LMIs). The delay stability interval of the system is improved, and the control effect is good.

Description

Technical field [0001] The present invention belongs to the technical field of wide-area power system analysis, and specifically relates to an analysis method that reduces conservative time-delay power system stability. At the same time, the present invention also relates to a feedback controller for time-delay power system stability. Background technique [0002] At present, there are two main methods for analyzing the stability of time-delay power systems. One is the frequency domain method, which mainly transforms the characteristic equations of the time-delay system and obtains the distribution of corresponding eigenvalues. The calculation process is very complicated to judge the stability of the power system, and once the operating state of the power system jumps or contains time-varying parameters, this method is difficult to work. Compared with the frequency domain method, due to its obvious superiority when dealing with system operation state jumps or time-varying paramet...

Claims

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Application Information

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IPC IPC(8): H02J3/00
CPCH02J3/00H02J2203/20
Inventor 钱伟王晨晨杨艺刘海波赵运基
Owner HENAN POLYTECHNIC UNIV
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