ANSI 27Q – reactive power undervoltage protection is a part of the fault ride-through protection group. It prevents voltage collapse by monitoring voltage and reactive power levels and activating corrective actions when necessary.
In case of grid disturbance and voltage drop, a distributed power source must support the grid and inject reactive power to the net and help grid voltage recovery.
In case that the power plant is failing to do so, reactive power undervoltage protection can detect it and disconnect the generating unit drawing the reactive power from the grid or taking other necessary actions.
In case that protection has tripped the generating unit and the voltage and frequency levels have normalized in the grid, after adjustable delay time, this function has also an automatic reclosing option to connect the plant back to the grid.
This protection function is included in SYMAP®Compact(+)F3, F4 and GC.