Simulation Of TCSC And UPFC Applied In Electric Power System

The research of Flexible AC Transmission System (FACTS) has become thefocus in the academe all over the world. Thyristor Controlled Series Compensation(TCSC) is one of the most important members in the FACTS family. It is very necess-ary to learn how it affects to power system. In this paper, one-phase and three-phasesystems are built by using Matlab PSB firstly. And TCSC models are added to thesystems. Then, static process is simulated in one-phase system with rated load andover load respectively under the Simulink circumstance. And the voltage of load inthe system with TCSC is compared with that of the system without TCSC. Transientprocess is simulated in three-phase system with every kind of fault. And the voltage ofload and power flow in the system with TCSC is compared with that of the systemwithout TCSC. What's more, the performance of TCSC could be affected by its place.For this reason, in the three-phase model, TCSC is placed on the local bus or remotebus of high voltage transmission lines, and the results are compared between them.The simulating results show that TCSC can control the power flow, damp theoscillations on lines and enhance transient stability of power system. In steady state,TCSC can improve the transfer capability and lessen the loss on transmission lines. Intransient state, TCSC can damp the power oscillations and improve the stability. Theplace of TCSC will affect both the overshot and stabilization time of the system intransient process. Overshot is relatively smaller and the voltage of load in transientprocess is symmetrical, but stabilization time of the system is longer when TCSC isplaced on the local bus. The situations are reverse while TCSC is on the remote bus.UPFC will be widely assembled in power system since its outstanding abilities inpower and voltage control. This thesis set up a simulink model of UPFC after analyzeits principle. And then, this model was applied into a three-phase system to observe itsinfluences to power quality. At first, this paper researched the ability of UPFC tostabilize active and reactive power after a three-phase fault in transmission line. Thecharacteristics of damp power pulse when a new equipment switch into a stablesystem is also analyzed.At last, whether UPFC could compensate system's voltage isresearched. As a result, it's obvious that UPFC could keep system voltage in sinewave when in three-phase fault. On the other hand, it was found that UPFC has nonegative influence to voltage of stable system.