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Control method and system for suppressing low-frequency oscillation during photovoltaic power generation

A control method and low-frequency oscillation technology, applied in the direction of reducing/preventing power oscillation, circuit devices, AC network circuits, etc., can solve problems affecting the power generation capacity of photovoltaic systems, reduce the active power of photovoltaic output, and change the steady-state operating point, etc., to achieve Avoidance of power generation capacity, avoidance of power generation capacity effects, avoidance of utilization effects

Pending Publication Date: 2018-06-29
CHINA ELECTRIC POWER RES INST +3
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This power-reducing operation mode reduces the active power of photovoltaic output to a certain extent, and also changes the steady-state operating point during the low-frequency oscillation process of the system, which may cause new oscillations when the photovoltaic power station switches back to the maximum power tracking operation mode. Affects the power generation capacity of the photovoltaic system, so it is necessary to improve

Method used

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  • Control method and system for suppressing low-frequency oscillation during photovoltaic power generation
  • Control method and system for suppressing low-frequency oscillation during photovoltaic power generation
  • Control method and system for suppressing low-frequency oscillation during photovoltaic power generation

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Embodiment 1

[0070] The present invention provides a control method for suppressing low-frequency oscillation of photovoltaic power generation based on reactive power modulation. The flow chart is as follows Figure 4 shown, including:

[0071] S11. Input the collected active power amplitude of the grid-connected point of the photovoltaic power station into the pre-established control model of the low-frequency oscillation suppression device, and calculate the control output signal value;

[0072] S12. Superimpose the control output signal value with the reference value of the reactive power / voltage control loop of the photovoltaic power generation system, and participate in the control of the reactive power / voltage control loop of the photovoltaic power generation system;

[0073] The pre-established control model of the low-frequency oscillation suppression device includes a DC blocking link, two lead-lag links, a proportional link and a limiting link.

[0074] The set grid-connected po...

Embodiment 2

[0107] figure 1 It is a structural diagram of a photovoltaic power station access system example. The example system is based on the commonly used two-region four-machine system for studying low-frequency oscillation problems at home and abroad, adding photovoltaic power station access. figure 2 It is the control model diagram of the low-frequency oscillation suppression device. The control model includes a DC blocking link, two lead-lag links, a proportional amplification link and a limiting link, which can be used to suppress different low-frequency oscillation phenomena. Table 1 is a comparison table of modal analysis results when the low-frequency oscillation controller is not turned on / on, Figure 4 It is a comparison chart of the time-domain simulation results when the low-frequency oscillation controller is not turned on or turned on under the short-circuit condition of the system. From Table 1 and Figure 4 It can be seen that after the low-frequency oscillation con...

Embodiment 3

[0112] Based on the same inventive concept, the present invention also provides a control system for photovoltaic power generation to suppress low-frequency oscillations, including:

[0113] The limiting link calculation module is used to input the set grid-connected point parameters of the photovoltaic power station into the pre-established control model of the low-frequency oscillation suppression device, and calculate the limiting link signal value;

[0114] The reactive power / voltage control loop calculation module is used to superimpose the signal value of the limiting link on the reactive power / voltage control loop reference value of the photovoltaic power generation system as a new reference value, and perform Enter reactive power / voltage control loop operation;

[0115] The pre-established control model of the low-frequency oscillation suppression device includes a DC blocking link, two lead-lag links, a proportional link and a limiting link.

[0116] The limiting lin...

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Abstract

The invention relates to a control method and a control system for suppressing low-frequency oscillation during photovoltaic power generation. The control method comprises the following steps: inputting the amplitude value of active power of a grid-connected point of a photovoltaic power station into a pre-established control model of a low-frequency oscillation suppressing device, and calculatinga control output signal value; superposing the control output signal value with a reference value of a reactive power / voltage control loop of a photovoltaic power generating system, and participatingin control of the reactive power / voltage control loop of the photovoltaic power generating system, wherein the pre-established control model of the low-frequency oscillation suppressing device comprises a blocking link, two lead-lag links, a proportional link and an amplitude limiting link. The technical scheme provided by the invention is an additional photovoltaic power generation damping control method for effectively suppressing the low-frequency oscillation of a power system; through the reactive power adjusting margin and the reactive power adjusting capability of the photovoltaic powergenerating system, the low-frequency oscillation is suppressed, so that utilization of the active power by the existing method is avoided and influence on the power generating capability of the photovoltaic system is avoided.

Description

technical field [0001] The invention relates to a control method and system for a photovoltaic power station, in particular to a control method and system for photovoltaic power generation to suppress low-frequency oscillation. Background technique [0002] In recent years, photovoltaic power generation has developed rapidly around the world, and a large number of centralized large-scale photovoltaic power stations have been connected to the grid or are under planning and construction, such as Ontario photovoltaic power station (100MW) in Canada, Yuma County, AZ power station (250MW) in the United States, China Golmud Power Station (300MW), etc. These power stations are often at the end of the system and are often sent to the load center through long-distance lines. The low-frequency oscillation of the system is generally caused by the negative damping effect of the system, which often occurs on weakly connected, long-distance, and heavy-duty transmission lines. Studies have...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02J3/24
CPCH02J3/24H02J2203/20
Inventor 赵大伟钱敏慧马进赫卫国夏烈姚良忠陈梅吴福保丁杰朱凌志周邺飞姜达军刘艳章韩华玲张磊包斯嘉吴蓓蓓彭佩佩
Owner CHINA ELECTRIC POWER RES INST
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