Impact of Short-Term Power Shortage from Low Voltage Ride through and DC Commutation Failure on Power Grid Frequency Stability

Countries worldwide are advocating for energy transition initiatives to promote the construction of low-carbon energy systems. The low voltage ride through (LVRT) characteristics of renewable energy units and commutation failures in line commutated converter high voltage direct current (LCC-HVDC) systems at the receiving end leads to short-term power shortage (STPS), which differs from traditional frequency stability issues. STPS occurs during the generator’s power angle swing phase, before the governor responds, and is on a timescale that is not related to primary frequency regulation. This paper addresses these challenges by examining the impact of LVRT on voltage stability, developing a frequency response model to analyze the mechanism of frequency instability caused by STPS, deriving the impact of STPS on the maximum frequency deviation, and introducing an energy deficiency factor to assess its impact on regional frequency stability. The East China Power Grid is used as a case study, where the energy deficiency factor is calculated to validate the proposed mechanism. STPS is mainly compensated by the rotor kinetic energy of the generators in this region, with minimal impact on other regions. It is concluded that the energy deficiency factor provides an effective explanation for the spatial distribution of the impact of STPS on system frequency.