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Photovoltaic collection system direct-current inter-electrode short-circuit fault ride-through method and device and medium

A short-circuit fault and pole-to-pole technology, applied in photovoltaic power generation, single-grid parallel feeding arrangement, etc., can solve the problem of long power interruption time, and achieve the effect of improving the success rate, avoiding blocking and downtime, and improving system availability.

Active Publication Date: 2020-11-17
XIAN XJ POWER ELECTRONICS TECH +4
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to provide a DC inter-pole short-circuit fault ride-through method, device and medium of a photovoltaic collection system to solve the problem of long power interruption time during non-serious DC inter-pole short-circuit faults

Method used

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  • Photovoltaic collection system direct-current inter-electrode short-circuit fault ride-through method and device and medium
  • Photovoltaic collection system direct-current inter-electrode short-circuit fault ride-through method and device and medium
  • Photovoltaic collection system direct-current inter-electrode short-circuit fault ride-through method and device and medium

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Embodiment 1

[0046] The present invention provides a short-circuit fault ride-through method between DC poles of a photovoltaic DC boost collection system, such as figure 1As shown in the figure, it is a schematic diagram of a short-circuit fault between DC poles of a photovoltaic DC boost collection system. The photovoltaic power generation is collected on the DC bus through a Maximum Power Point Tracking controller (Maximum Power Point Tracking, MPPT) and a DC boost converter (DC / DC). A short-circuit fault occurs on the DC bus during a short-circuit fault between DC poles, for example, the two poles of the DC bus are grounded.

[0047] Such as figure 2 As shown in , after detecting the short-circuit fault between DC poles, when the fault does not cause the DC boost converter to be blocked, the steps to realize the fault ride-through are as follows:

[0048] 1) Calculate the DC voltage control command value of the MPPT output side according to the fault transition resistance value and t...

Embodiment 2

[0062] The present invention provides a short-circuit fault ride-through method between DC poles of a photovoltaic DC boost collection system, such as image 3 As shown in , after detecting the short-circuit fault between DC poles, when the fault causes the DC boost converter to be blocked, the steps to realize the fault ride-through are as follows:

[0063] (1) Control MPPT zero power operation.

[0064] The system has a short-circuit fault between the poles of the DC bus bar, and after the fault causes the DC boost converter to be blocked, the DC voltage at the output end of the MPPT is out of control, and the power cannot be sent out. In order to ensure power balance and the continuous and stable operation of the system, the photovoltaic The generated power is reduced to zero, that is, the MPPT is controlled to run at zero power.

[0065] Generally, the MPPT control mode can be switched to the output DC voltage control mode. At this time, due to the blocking of the DC boos...

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Abstract

The invention relates to a photovoltaic collection system direct-current inter-electrode short-circuit fault ride-through method, device and medium, and the method comprises the steps: calculating a direct-current voltage control instruction value according to a fault transition resistance value and a system power generation power limit when a photovoltaic direct-current boost collection system direct-current inter-electrode short-circuit fault is not a severe fault; and the MPPT is controlled to work in an output end direct-current voltage control mode, and after it is detected that the direct-current inter-electrode short-circuit fault is removed, the direct-current boost converter is charged, and power transmission is recovered. The MPPT does not stop, the voltage control instruction value is determined by the fault transition resistance value and the system power generation power limit, the fault transition resistance is introduced to absorb a certain power, and the absorbed poweris within the photovoltaic power generation power capability range, so that the success rate of crossing implementation of the system is improved; by applying the method, shutting down of the whole system is avoided, the power interruption time is shortened, and the system availability is improved.

Description

technical field [0001] The invention relates to the technical field of new energy grid-connected power generation, in particular to a method, device and medium for short-circuit fault ride-through between DC poles of a photovoltaic collection system. Background technique [0002] At present, the photovoltaic power station adopts AC collection and transmission, and a large number of inverters are coupled with long-distance cables. The voltage limit and wide-frequency oscillation problems restrict the transmission capacity of the photovoltaic power station, and the loss of AC lines affects the overall efficiency of the system. With the development and maturity of power electronics and DC transmission technology, it is possible for photovoltaic power plants to use DC boosting and collecting and sending. The DC collection system has higher stability, no need for reactive power compensation, and the transmission capacity is stronger and the loss is smaller under the same voltage ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02J3/38
CPCY02E10/56
Inventor 行登江杨美娟李道洋张浩辛德锋
Owner XIAN XJ POWER ELECTRONICS TECH