Abstract: With the continuous increase of UHV external power into Shandong and the rapid growth of new energy power generation,the frequency control of Shandong power grid has attracted more and more attention.The occasional area control error（ACE）regulation of Shandong power grid is not coordinated with the unit control,which makes it difficult to adjust ACE within a day.The ACE and regulation rate of the power grid side were analyzed based on the grid-source online monitoring platform.It was found that the up-regulation rate of AGC-R mode units is lower than the down-regulation rate,and the up-regulation rate of units is insufficient when ACE of power grid is negative. Typical units were selected to analyze the action of primary frequency regulation and AGC regulation from generation side.It was concluded that the main reason for the difficulty of ACE regulation is that the direction of power grid ACE is opposite to that of thermal power primary frequency regulation.The secondary reasons are that the primary frequency regulation of units is larger than the theoretical value and the coordinated control quality of some units is poor.The corresponding countermeasures to deal with the abnormal ACE regulation of Shandong power grid were put forward,which has guiding significance for improving the ACE regulation level of power grid and the AGC regulation quality of units.