The Effect Of Load Models On Power System Stability Calculations

With the scale of the power system is constantly expanding and becomes moreand more complicated.The stability of power system is increasingly need to attracteveryone’s attention. And the power load has a very serious impact on the stabilitycalculations of the grid. The work selecting load model is very important, overlyoptimistic or overly pessimistic models may lead to economic loss and other seriousconsequences. So the study in the impact of selected electrical load model on thestability calculations of the grid has important significance.Firstly, this thesis make a detailed presentation in the concept of basic theoreti-cal knowledge about electrical load like classification. Then use the PSAT simulationsoftware to simulate the IEEE three generators-nine nodes system. First simulate theimpact of static load model on transient stability result of the power system.Thensimulate the impact of the static model and the induction motor model ontransmission capacity calculations. From the simulation, When all the load models arethe constant impedance model, the result is the least optimistic. And when all loadmodels are the constant power model, the result is the most optimistic. Whenconducting simulation about the transmission capacity, we can be obtained: When thethree loads are all constant impedance load model, the transmission power of thesystem is maximum; When the three loads are all induction motor load model, theminimum transmission power system is least. Then use the PSAT simulation softwareto simulate the IEEE ten generators thirty nine nodes system under different loadmodels in order to get the critical clearing time. And come out with the result that thecritical clearing time under different load models are different, which has certain rulesto follow.This thesis analyzes the selection on load models has a impact in the transientstability result of the power system, transmission capacity calculations and the criticalclearing time calculations,and it has a certain reference on selecting models.