DSP-based low-voltage ride-through area general judgment method

Abstract

The invention discloses a DSP-based low-voltage ride-through area general judgment method. The method is characterized by, in the DSP initialization program, setting the shape of a low-voltage ride-through area, judgment of the low-voltage ride-through area being executed in a DSP timer interrupt function; defining a time counting variable and assigning an initial value to the time counting variable; when executing the interrupt function every time, measuring a grid-connection point voltage per-unit value, and calculating time decreasing step length according to the low-voltage ride-through area shape regulated in grid-connection standard; and subtracting the time counting variable by the time decreasing step length to judge whether the system is inside or outside the low-voltage ride-through area, and furthermore, carrying out corresponding control strategies. The method can judge the low-voltage ride-through area through a time counting variable decreasing method, and the time decreasing step length changes with the degree of voltage drop; and the judgment method is high in universality, is suitable for requirements for the low-voltage ride-through area of different grid-connection standards, and can provide convenience for low-voltage ride-through control.

Description

technical field [0001] The invention relates to the field of new energy grid-connected power generation, and specifically refers to a general judgment method for a low-voltage ride-through area implemented in a digital signal processor (DSP). Background technique [0002] In large-scale photovoltaic and wind power plants, grid-connected standards strictly require that they have low-voltage ride-through functions. Low voltage ride through means that when the grid failure or disturbance causes the voltage drop at the grid connection point, within a certain voltage drop range and time interval, the photovoltaic inverter or wind turbine can run continuously without interruption. For large-scale photovoltaic or wind power plants, it is also required to be able to output reactive power during grid voltage drops to support the rapid recovery of grid voltage. And when the grid-connected point voltage exceeds the specified drop range and time interval, the photovoltaic inverter and ...

AI Technical Summary

Problems solved by technology

For different degrees of voltage drop, the time of low voltage ride-through is different, how to accurately and effectively judge this area is very complicated

In addition, there are differences in low-voltage ride-through areas stipulated by different grid-connected standards, which increases the difficulty of judging low-voltage ride-through areas

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