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Safe operation method and system for subsynchronous oscillation wind power grid-connected system

A sub-synchronous oscillation and system security technology, applied in wind power generation, control systems, single-network parallel feed arrangements, etc., can solve problems such as endangering the safe and stable operation of the power system, large oscillation amplitude, and damage to power equipment

Active Publication Date: 2019-04-12
NORTH CHINA ELECTRIC POWER UNIV (BAODING)
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The subsynchronous oscillation has a large amplitude and long duration in the power network, which may damage the power equipment or even endanger the safe and stable operation of the power system

Method used

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  • Safe operation method and system for subsynchronous oscillation wind power grid-connected system
  • Safe operation method and system for subsynchronous oscillation wind power grid-connected system
  • Safe operation method and system for subsynchronous oscillation wind power grid-connected system

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0136] figure 1 It is a method flowchart of Embodiment 1 of the method for safe operation of a wind power grid-connected system aimed at subsynchronous oscillation in the present invention.

[0137] see figure 1 , the safe operation method of wind power grid-connected system for subsynchronous oscillation, including:

[0138] Step 101: Obtain the interharmonic current vector: obtain the interharmonic current obtained by real-time monitoring of the interharmonic in the wind power grid-connected system, and obtain the interharmonic current vector;

[0139] Step 102: Calculate the Oscillation Propagation Factor: Using the formula Calculate the oscillation propagation factor; k i (s) is the oscillation propagation factor corresponding to the i-th element in the output vector of the generator under test; |Δy i |is the magnitude of the i-th element in the output vector of the generator to be tested, Δu j is the jth element of the interharmonic current vector; ||Δu|| 2 is the ...

Embodiment 2

[0199] This embodiment mainly provides calculation example simulation and analysis.

[0200] image 3 It is a system structure diagram of the four-machine two-zone system in Embodiment 2.

[0201] see image 3 , two DFIGs are connected to the four-machine two-zone system, and the image 3 The system conducts small disturbance stability analysis and obtains 7 natural oscillation modes. Table 1 is the list of natural oscillation modes of the system. See Table 1, the real part of the characteristic root of the system is negative, and the system is stable with small disturbances.

[0202] Table 1

[0203]

[0204] Frequency domain analysis:

[0205] Assuming that DFIG1 is disturbed, inter-harmonic currents are injected into the power grid, and the inter-harmonics are used as input variables, and the output active power of each doubly-fed fan and synchronous generator is used as output vectors to establish a system transfer function and find its oscillation propagation fact...

Embodiment 3

[0218] The invention also discloses a wind power grid-connected system safe operation system for sub-synchronous oscillation, including:

[0219] The harmonic acquisition module is used to obtain the inter-harmonic current obtained by real-time monitoring of the inter-harmonic in the wind power grid-connected system, and obtain the inter-harmonic current vector;

[0220] Oscillation propagation factor calculation module for using the formula Calculate the oscillation propagation factor; k i (s) is the oscillation propagation factor corresponding to the i-th element in the output vector of the generator under test; |Δy i |is the magnitude of the i-th element in the output vector of the generator to be tested, Δu j is the jth element of the interharmonic current vector; ||Δu|| 2 is the second norm of the interharmonic current vector; W ij (s) is the sinusoidal response from the j element of the interharmonic current vector to the i element in the output vector of the gene...

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Abstract

The invention discloses a safe operation method and system for a subsynchronous oscillation wind power grid-connected system. The method comprises the following steps: obtaining inter-harmonic currentobtained by carrying out real-time monitoring on inter-harmonics in the wind power grid-connected system so as to obtain an inter-harmonic current vector; inputting the inter-harmonic current vectorto calculate an oscillation propagation factor; judging whether the oscillation propagation factor is greater than a preset threshold value so as to obtain a judging result, when the judging result indicates that the oscillation propagation factor is greater than the preset threshold value, determining that subsynchronous oscillation is propagated to an electric generator to be measured, and cutting off draught fans causing subsynchronous oscillation from the wind power grid-connected system, and when the judging result indicates that the oscillation propagation factor is smaller than or equalto the preset threshold value, determining that subsynchronous oscillation is propagated in the range of a draught fan group only, and adjusting the operating parameter suppression inter-harmonics ofthe draught fan group. According to the safe operation method and system for the subsynchronous oscillation wind power grid-connected system disclosed by the invention, subsynchronous oscillation canbe monitored, and safe operation of the wind power grid-connected system is guaranteed when subsynchronous oscillation occurs.

Description

technical field [0001] The invention relates to the field of safe operation of power grids, in particular to a method and system for safe operation of a wind power grid-connected system aimed at subsynchronous oscillations. Background technique [0002] New energy sources such as wind power and photovoltaics have become an important part of the power system. With the continuous increase of the proportion of new energy, the stability of the power system caused by the access of new energy has received extensive attention. Wind energy is one of the best solutions for new energy generation. At present, doubly-fed induction wind turbines and direct-drive permanent magnet wind turbines are the mainstream models in wind farms. In order to improve the stability and reliability of the wind power grid-connected power system, it is necessary to conduct a more in-depth study on the subsynchronous oscillation phenomenon in the wind power power system. [0003] Doubly Fed Induction Gen...

Claims

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Application Information

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IPC IPC(8): H02J3/38H02J3/01H02P9/00
CPCH02J3/002H02J3/01H02J3/386H02J2203/20H02P9/007Y02E10/76Y02E40/40
Inventor 王彤杨京王增平
Owner NORTH CHINA ELECTRIC POWER UNIV (BAODING)
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