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Online analysis and early warning method for low-frequency oscillation of electric power system

A low-frequency oscillation and power system technology, applied to electrical components, circuit devices, AC network circuits, etc., can solve problems such as complex calculations, difficulty in distinguishing the law of carrier signal changes at symbol reversal points, and large processing errors, so as to avoid integral operations , fast response capability, robustness, and calculation accuracy satisfy the effect

Active Publication Date: 2011-08-31
CENT CHINA GRID +1
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Problems solved by technology

The disadvantage of this method is that the process of solving the damping ratio involves a large number of integrals, and the calculation is complicated
This method has reference significance in low-frequency oscillation early warning, but its shortcoming is that the frequency detection adopts the zero-crossing detection method, which only takes into account the number of positive and negative changes of the value at the sampling point, and the amplitude of the carrier signal attenuates to zero at the symbol flip. Signal, in the case of limited quantization accuracy, it is difficult to distinguish the change law of the carrier signal at the symbol flip point, and the frequency identification accuracy is limited; in addition, the Prony algorithm is a spectrum analysis method suitable for linear systems. Data processing errors are large

Method used

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  • Online analysis and early warning method for low-frequency oscillation of electric power system
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  • Online analysis and early warning method for low-frequency oscillation of electric power system

Examples

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Embodiment 1

[0042] A low -frequency oscillating online analysis and early warning method of power system, which contains the following steps:

[0043] A. Collect relative skills from the phase angle measurement unit (PMU) of the high -voltage synchronization power grid wide -area measurement system, and use the time of relative skills and the time to collect the relative corner as a sample data, so as to use Collect dot data for sampling frequency, of which 8 Hz ≤ ≤15Hz;

[0044] B. In the order of the data of the data, take n duty data continuously, and the data of N duty points constitutes a WAMS data set, of which 150≤n ≤ 2000;

[0045] C. Perform the median filtering or K point of the WAMS data set. Among them, 3 ≤ k ≤ 9, the relative kinetic signal after filtering It

[0046]D. Use TeaGAR energy operator to process relative kine The

[0047] D1, Calculating Relators Signal Teagar energy operator:

[0048] (1)

[0049] (2)

[0050] (1), (2) j = 3,4, ..., n-3;

[0051] D2, calcula...

Embodiment 2

[0069] A low -frequency oscillation of electric power systems online analysis and warning method. The steps of this method are the same as the embodiment. Taking the relative skill signal of the No. 7 machine in the 8 machine system in PSASP as an example, in the step A,Pick = 15Hz, take n = 150 in step b, k = 7 in step C, and take H = 75 in step i, G7-G1 relative kinetic signal EMD decomposition results see the manual attached instructions attached to the manual attachment figure 2 The energy statistics of the G7-G1 relative skills and its EMD component are as shown in Table 1, Table 1, E0 is the energy of the original signal. E1, E2, E3, E4, and E:R's energy, in the content of the internal mode of C1 ~ C4, the IMF component C1 with the largest energy weight C1 is the dominant oscillation mode.

[0070] 8 The Q-R feature analysis results of the 8 machine system are as shown in Table 2, 0.77Hz, which is the weakest and stronger mode of damping, and is the leading oscillation mode...

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Abstract

The invention discloses an online analysis and early warning method for low-frequency oscillation of electric power system, relating to the safe operation of electric power system. The method comprises the steps that: oscillation frequency is obtained by carrying out K point median filtering over collected relative power angle in a power grid wide-area measurement system and via Teagar energy operator; and when power oscillation with the oscillation frequency between 0.1-0.2 Hz exists in power grid, the damping ratio dominating oscillation mode can be worked out through a signal energy analysis method based on EMD, thus to realize online analysis and early warning for low-frequency oscillation. The advantages of the invention include that the Teagar energy operator can rapidly work out the frequency of the relative power angle in the power grid; the algorithm of the damping ratio is simplified; large amount of integral operation can be avoided; the calculation is much simpler and morerapid; and the online analysis and early warning for low-frequency oscillation in power grid is realized.

Description

Technical field [0001] The invention involves the safe operation of the power system, and it is more specifically involved in the measurement and analysis of the low -frequency oscillation of the grid in the power grid wide -area measurement system (WAMS). Background technique [0002] The low -frequency oscillating occurred in the power system is derived from the relative sway between the generator or generator group rotor.It is the continuous oscillation of the effective power in the system when there is a local contribution surplus or lack in the system, and the related generator or generator group is accelerated to achieve a contribution balance.The power oscillation between the oscillation frequency between 0.1 and 2.5Hz is called low -frequency oscillation or electromechanical oscillation.Low -frequency oscillations often occur on long -distance and heavy load transmission lines, especially in the incentives system that uses a rapid amplification multiple. Low -frequency os...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02J3/00
Inventor 徐友平党杰刘涤尘廖清芬李勇刘天斌王娜娜董飞飞
Owner CENT CHINA GRID
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