A fault protection and energy stabilization circuit for wind farms

Abstract

Provided is a fault protection applied to a wind power plant and an energy stabilization circuit. A power converter is composed of a voltage source converter and a chopper or a current source converter. A direct current end of a rectifier is connected with a switch provided with an antiparallel diode and a buffer absorption circuit in parallel. A primary side of a single-phase transformer is connected with a switch and a resistor in parallel, and a secondary side of the single-phase transformer is connected with an alternative current output end of the rectifier. The primary side of the single-phase transformer is respectively connected with a power grid and a switching-in end of the wind power plant. A three-phase alternative current end of a power converter is connected with the power grid and a switching-in end of the wind power plant through a three-phase filter circuit and a three-phase transformer. A direct current end of the power converter is connected with a direct current end of the rectifier in series and then connected with an energy storage inductor in series. Under a normal condition, power output of the wind power plant is smoothed through charging and discharging of the energy storage inductor. Under a fault condition, the energy storage inductor is firstly utilized to limit current, then a thyristor of the rectifier is turned off, and the energy storage inductor is disengaged from the power grid. Current is limited through the resistor connected with the primary side of the transformer in parallel.

Description

technical field [0001] The invention relates to a fault protection and energy stabilization circuit for a wind farm. Background technique [0002] Wind power is developing rapidly around the world, and its proportion in the grid is gradually increasing. As the proportion of wind power in the grid continues to increase, wind power has an increasing impact on grid stability and power quality. In order to reduce the impact of wind power generation on the power grid, countries around the world have gradually introduced grid-connected standards for wind power generation, one of which is to require wind power generators to be disconnected from the power grid only when they meet certain requirements when the voltage is low. In order to meet the requirements of low-voltage grid connection, various low-voltage ride-through technologies have been gradually developed. Various low-voltage ride-through technologies are mainly divided into two types: 1. Using fault protection circuits....

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Problems solved by technology

The above two methods can play a certain role, but still have the following deficiencies: 1. The current fault protection circuit needs to trigger the corresponding circuit to protect after detecting the fault signal, so it has a certain delay and cannot play a role. The role of complete protection

2. Adopting the improved control method needs to increase the capacity of the converter, and there is nothing to do when the voltage drops deeply

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