Low voltage ride-through testing method based on power grid voltage sag composite simulation structure

A low-voltage ride-through and grid voltage technology, which is applied in the direction of measuring electricity, measuring devices, and measuring electrical variables, etc., can solve problems such as grid influence, voltage drop depth cannot be continuously adjusted, and voltage drop at public connection points

Active Publication Date: 2012-04-25
STATE GRID ELECTRIC POWER RES INST
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  • Abstract
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  • Claims
  • Application Information

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Problems solved by technology

(3) During detection, a voltage drop occurs at the common connection point, which affects the power grid
(4) The voltage drop depth cannot be adjusted continuously, and the recovery curve is stepped

Method used

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  • Low voltage ride-through testing method based on power grid voltage sag composite simulation structure
  • Low voltage ride-through testing method based on power grid voltage sag composite simulation structure
  • Low voltage ride-through testing method based on power grid voltage sag composite simulation structure

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Embodiment Construction

[0017] The present invention will be further described in detail below with reference to the accompanying drawings and examples. However, the invention is not limited to the examples given.

[0018] For example image 3 It is a schematic diagram of the circuit structure of the present invention for detection of low-voltage ride-through capability of photovoltaic power plants. The solid line box in the figure represents the specific implementation of the method of the present invention, including an impedance transformation unit and a power electronic converter, wherein the impedance transformation unit is composed of a current-limiting reactance Composed of transformer X1 and grounding reactor X2, the power electronic converter is a high-voltage inverter device composed of back-to-back four-quadrant converters combined with phase-shifting transformers using virtual impedance control technology.

[0019] The photovoltaic power plant under test is normally connected to the grid...

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Abstract

According to the invention, a mode in which a power electronic converter and an impedance conversion unit are in series connection is employed; the power electronic converter employs a high voltage frequency converter scheme, so that a voltage sag type, voltage sag duration, a voltage sag depth and a voltage sag phase can be effectively controlled; and the impedance conversion unit employs a scheme in which stepping switching is carried out on a combined reactor, so that simulation on a power grid voltage, a phase, a frequency and an impedance characteristic during a power grid voltage sagging process is realized and a real situation of the power grid voltage sagging process can be reflected. Moreover, according to the invention, a problem that a real situation of a power grid voltage sagging process can not be accurately simulated without considering changes of a voltage phase and an impedance during the power grid voltage sagging process in the power electronic converter method can be solved, so that real simulation on transient characteristics of the voltage, the phase, the frequency and the impedance of the power grid during the power grid voltage sagging process is realized and a real situation of the power grid voltage sagging process is reflected; besides, a virtual impedance control technology is introduced into the power electronic converter, so that no influence is exerted on a voltages of a grid-connected point when the voltage is sagged.

Description

technical field [0001] The method relates to a testing technique for realizing low voltage ride-through capability. Background technique [0002] In recent years, my country's photovoltaic industry has developed rapidly. With the increasing proportion of photovoltaic power generation in the power grid, the inherent volatility, intermittent and periodic characteristics of photovoltaic power generation will affect the voltage and frequency characteristics of the power grid, seriously Sometimes even cause grid stability problems. If the photovoltaic power station is cut off immediately when the power grid fails and the voltage drops, it will cause a drastic change in the power flow of the system and cause a large-scale power outage. In order to ensure the safe, reliable and stable grid-connected power generation of photovoltaic power plants, according to the requirements of the State Grid Corporation of China's "Technical Regulations for Connecting Photovoltaic Power Plants to ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R31/00
Inventor 张军军包斯嘉郭自勇李红涛崔效毓吴蓓蓓
Owner STATE GRID ELECTRIC POWER RES INST
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