Power flow calculation of power system is a basic electrical calculation to study the stable operation of power system. Its task is to determine the operating state of the whole system according to the given operating conditions and network structure, such as voltage (amplitude and phase angle) on each bus, power distribution and power loss in the network, etc. The result of power flow calculation is the basis of power system stability calculation and fault analysis.

Importance of power flow calculation;

(1) In the power grid planning stage, through power flow calculation, the power supply capacity and access points are reasonably planned, the power grid structure is rationally planned, and the reactive power compensation scheme is selected to meet the requirements of power flow exchange control, peak shaving, phase modulation and voltage regulation in large and small modes at the planning level.

(2) When compiling the annual operation mode, based on the expected load growth and the commissioning of new equipment, the typical mode is selected to calculate the power flow, find out the weak links in the power grid, and provide reference for the dispatcher's daily dispatching control, and put forward suggestions to the planning and infrastructure departments to improve the power grid structure and speed up the infrastructure progress.

(3) Power flow calculation under normal maintenance and special operation mode is used to compile daily operation mode, guide power plant startup mode, active and reactive power adjustment scheme and load adjustment scheme, and meet the thermal stability and voltage quality requirements of lines and transformers.

(4) Analyze the influence of expected accidents and equipment outage on static safety, and formulate the adjustment scheme of expected operation mode.