在电网发生扰动后，不同位置节点的频率会出现偏差，称为频率的空间分布。在以往的研究中，分频器公式已被提出用于估计电网的频率分布，但该公式的推导中采用了一些假设和简化，会导致较大的误差。论文基于复频率的概念，严格推导了电网中节点电压复频率和同步发电机内电势复频率之间的关系，提出了一个精确估计频率分布的公式。通过该公式，可以了解电网的频率空间分布机制，揭示频率分布的内在规律，说明频率的分布水平与网络的阻抗分布和电压水平相关。和已有分频器公式相比，网络电阻、负荷、节点电压与发电机内电势的幅值和角度等因素都被更加合理的考虑在内，严格推导过程使得所提出公式具有更高的精度。在IEEE 10机39节点系统和50机145节点系统中设置的时域仿真结果验证了该公式的准确性。

After a disturbance in the power grid, frequencies at different buses are different, which is called spatial distribution of frequency. The frequency divider (FD) formula has been proposed to estimate the frequency distribution of a power grid, but the derivation of the formula involves some assumptions and simplifications which may lead to large errors. This work derives a formula to accurately estimate the frequency distribution based on the concept of complex frequency (CF), which considers both the changes in magnitude and angle of a phasor. By using this formula, we can understand the frequency spatial distribution mechanism of the power grid and reveal the inherent laws of frequency distribution, and demonstrate that the level of frequency distribution is related to the impedance distribution and voltage level of the network. Compared to FD, network resistance, load, magnitude and angle of voltages are all taken into consideration. The effectiveness of the formula is validated with simulation results in the IEEE 39-bus and IEEE 145-bus system.