Voltage fast detection algorithm suitable for grid power system low voltage ride through function

Abstract

The invention discloses a voltage fast detection algorithm suitable for a grid power system low voltage ride through function. The voltage fast detection algorithm suitable for the grid power system low voltage ride through function comprises the following steps: (1) acquiring amplitude value information under the normal operation of a power grid based on a phase-locked loop of a synchronous reference coordinate frame, (2) separating the voltage of a sampled power grid into three-phase of A, B, C, conducting a period of delay to the sampled power grid, and acquiring the absolute value of an difference value, (3) setting a voltage threshold value and comparing the difference value in the step (2) with the voltage threshold value, (4) if the difference value is smaller than the voltage threshold value, then judging that the voltage is normal, if the difference value is larger than the voltage threshold value, then turning to step (5), (5) sending real-time voltage signals into a maximum value tracking module and an over zero point tracking module through each of the phrases of voltage, after judging that the system enters into a low voltage status, and (6) recording the maximum value tracking module and the over zero point tracking module to acquire an amplitude value after the voltage of the power gird drops.

Description

technical field [0001] The invention relates to a fast voltage detection algorithm suitable for the low voltage ride-through function of a new energy grid-connected power generation system, in particular to a fast voltage detection algorithm suitable for the low voltage ride-through function of a grid-connected power generation system for improving the low voltage ride-through capability of new energy power generation detection algorithm. Background technique [0002] Low-voltage ride-through (LVRT) originally refers to the fact that when the voltage at the grid-connected point of the wind turbine drops, the wind turbine can remain connected to the grid, and even provide a certain amount of reactive power to the grid to support the recovery of the grid until the grid returns to normal, thereby "crossing" This low voltage time (area). With the rapid development of new energy power generation technology, especially the rapid development of photovoltaic power generation techno...

AI Technical Summary

Problems solved by technology

However, this method needs to transform and decouple the positive and negative sequence voltages at the same time. The implementation method is cumbersome, and the amplitude and phase angle of the three-phase voltages cannot be determined, and the drop information of the phase voltage amplitude cannot be accurately measured. Therefore, it is impossible to accurately perform reactive power compensation

In addition, its detection time is greatly affected by coordinate transformation and low-pass filter, so the detection time is also longer

To sum up, the main problem existing in the current three-phase voltage low-voltage detection is that if the three-phase phase-locked loop is used, the amplitude and phase angle of the three-phase voltage cannot be accurately detected, and the detection is greatly affected by the voltage imbalance. The number of phase-locked loops required to use a single-phase phase-locked loop is three, and the number of modules included in this way increases greatly, making it difficult to implement

In addition, the detection time of various existing detection methods is relatively long

Images