A ride-through operation method of dfig system under symmetrical voltage fault

A symmetrical fault and operation method technology, applied in wind power generation, electrical components, circuit devices, etc., can solve problems such as difficulty in maintaining grid-connected operation, achieve the effect of improving anti-interference ability, improving stable operation performance, and maintaining stability

Active Publication Date: 2021-06-11
HUAZHONG UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] Aiming at the above defects or improvement needs of the prior art, the present invention provides a ride-through operation method of the DFIG system under a symmetrical voltage fault, thereby solving the problem that the grid fault voltage in the prior art has adverse effects on the doubly-fed wind power generation system, and the wind turbines When the grid voltage fails, it is disconnected from the grid, and it is difficult to maintain the technical problem of grid-connected operation

Method used

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  • A ride-through operation method of dfig system under symmetrical voltage fault
  • A ride-through operation method of dfig system under symmetrical voltage fault
  • A ride-through operation method of dfig system under symmetrical voltage fault

Examples

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Embodiment 1

[0063] In order to verify the validity and feasibility of the control strategy proposed by the present invention, set up such as figure 1 The model shown. The first example is a verification strategy to enhance the low voltage ride-through capability of the DFIG system. In this calculation example, the wind speed is set to be 12m / s, and the reference value of the output reactive power is set to 0MVar. Set 0 to 5s as the normal operation state. After 5s, the three-phase voltage of the power grid A, B, and C will drop by 20% at the same time, and the SGSC voltage compensation control strategy will be started immediately after 5s.

[0064] Now the simulation results of the calculation example are analyzed to illustrate the effectiveness and feasibility of the present invention. It can be seen from Figure 6(a) that after 5s, the three phases of grid A, B, and C dropped symmetrically, and the peak value of the phase voltage dropped from 8.165kV to 6.53kV. Figure 6(b) is the volta...

Embodiment 2

[0068] The second example is the verification strategy to enhance the high voltage ride-through capability of the DFIG system. In this calculation example, the wind speed is also set at 12m / s, and the reference value of the output reactive power is set to 0MVar. Set 0 to 5s as the normal operation state. After 5s, the three-phase voltage of grid A, B, and C increases by 20% at the same time, and immediately starts the SGSC voltage compensation control strategy after 5s.

[0069] It can be seen from Figure 7(a) that after 5s, the three phases of grid A, B, and C experienced a symmetrical surge, and the peak value of the phase voltage rose from 8.165kV to 9.798kV. Figure 7(b) is the voltage between SGSC and grid , after being transformed by the transformer, the peak value of the phase voltage of the voltage rises from the previous 563V to 676V after 5s. Figure 7(c) is the compensation voltage output by SGSC. After 5s, the peak value of SGSC output is a phase voltage of 113V, an...

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Abstract

The invention discloses a method for running through a DFIG system under voltage symmetrical faults. The grid side of the DFIG system is provided with a series grid-side converter. The running method includes: when a symmetrical fault occurs in the grid voltage, obtain The positive sequence component of the stator voltage is calculated by using the positive sequence component of the grid voltage and the stator voltage to obtain the compensation voltage that the series grid side converter should output; the stator voltage and the parallel grid side converter are compensated by using the compensation voltage that the series grid side converter should output The AC voltage keeps the stator voltage, rotor voltage, stator current, and rotor current in the state before the fault, and at the same time keeps the AC voltage of the parallel-connected side converter unchanged, thereby stabilizing the DC bus voltage. The invention overcomes the bad influence caused by the fault voltage of the power grid on the doubly-fed wind power generation system, prevents the wind generator set from disconnecting from the power grid when the power grid voltage fails, and maintains grid-connected operation.

Description

technical field [0001] The invention belongs to the control technical field of a doubly-fed wind power generation system, and more specifically relates to a ride-through operation method of a DFIG system under voltage symmetrical faults. Background technique [0002] With the rapid development of power electronics and automatic control technology, renewable energy generation technology represented by wind power generation has made great progress. Features, decoupling control of active and reactive power, low cost and high efficiency have been widely used in wind power generation technology and become the mainstream model of wind farms. With large-scale wind farms connected to the grid, DFIG's control technology is also becoming more and more mature. However, in practical applications, with the substantial increase in the installed capacity of DFIG wind farms, more and more wind turbine off-grid accidents occur, and most of these off-grid accidents are due to the fact that w...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02J3/38
CPCH02J3/386Y02E10/76
Inventor 康祎龙苗世洪刘子文范志华晁凯云刘昱良刘君瑶李力行
Owner HUAZHONG UNIV OF SCI & TECH
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