Centralized low voltage ride through correction system

Abstract

The invention relates to a centralized low voltage ride through correction system, which is characterized in that: an energy absorbing resistor, a controllable power electronic device and a high-speed switch are connected in parallel between a current collection bus and a transformer; the parallel circuit is connected in parallel with a bypass switch between the transformer and the current collection bus; a static var generator SVG is arranged on the current collection bus; when the system operates normally, the bypass switch is turned off and the high-speed switch is closed; when the system fails, the high-speed switch is turned off; failure current flows by the energy absorbing resistor; the size of equivalent impedance is adjusted by controlling the conduction angle of the controllable power electronic device; and meanwhile, the static var generator SVG automatically enters a constant voltage working mode to stabilize bus voltage. The centralized low voltage ride through correction system has the beneficial effects that: the system is arranged between the current collection bus of a wind power station or a photovoltaic power station and a low voltage side of a main transformer in a centralized way; the problem of low voltage ride through can be effectively solved; and the low voltage ride through reconstruction cost of the wind power station or the photovoltaic power station can be greatly reduced.

Description

technical field [0001] The invention belongs to the field of power systems, and in particular relates to a low-voltage ride-through correction system that is centrally used in wind farms or photovoltaic power station collector buses. Background technique [0002] Low-voltage ride-through (LVRT) means that when the voltage of the wind turbine or photovoltaic power station grid-connected point drops, the wind turbine or photovoltaic power station can remain connected to the grid, and can provide a certain amount of reactive power to the grid to support the recovery of the grid until the grid returns to normal , thus "passing through" this low voltage time (area). LVRT is a specific operational functional requirement for grid-connected wind turbines or photovoltaic power plants to remain connected to the grid when the grid voltage drops. Only when the grid voltage drops below the specified curve can the wind turbine or photovoltaic power station be allowed to disconnect from t...

AI Technical Summary

Problems solved by technology

[0003] At present, the common devices to solve the problem of low voltage ride through are all aimed at a single wind turbine or a single photovoltaic inverter, the cost of transformation is high, and the progress of the project is slow

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