准同期并网中小容量发电机组频率不稳定性研究

从并网必须具备的3个条件入手,研究频率差和相角差的关系,阐述合闸相角差不满足条件时对系统的影响。在自备电厂中,由于发电机组的功率较小而负载较大,并网瞬间其频率会出现一定的波动,造成原本适合并网的频率差和相角差条件发生变化,影响并网的顺利实现。针对小容量发电机组频率易波动的情况,提出了基于ARM LPC1752芯片的硬件设计方法,通过改变采样间隔,实现了对发电机频率实时监测与调整,保证其与电网间的频差更小,使合闸时冲击电流更小。

Study on Frequency Instability of Small Capacity Power Units in Synchronized Grid-Connected

This paper starts on three qualifications of grid-connected and analyzes the relation between frequency difference and phase angle difference,elaborates the affects in grid-connected when the closing phase angle difference does not satisfy the condition. In power plants,for the power is small and loads is large,so at the moment of grid-connected,the frequency will oscillate in some way,affect the realization of grid-connected.Considering the frequency fluctuation of small capacity power units,the paper raises the hardware design method based on ARM LPC1752,and use the idea of changing sampling interval to realize generator frequency measurement and real-time adjustment,ensure frequency difference between generator and power network is smaller,so the impulse current also will be much smaller.