Research On UPFC And Its Application In Restraining Low Frequency Oscillation Of Grid

Today’s power system has gradually developed to a nonlinear dynamic system withcharateristics of big unit extra high voltage long distance and heavy loading. With thearising of new facilities,at the same time of amplifying power generation and transmissioncapacity expanding the complexity of system. The operation of the system is easier to closeto the ultimate state than ever before. This will lead to a series of stable operation problems.Low frequency oscillation has raised concern of the electricity workers because of causinglink overcurrent tripping operation system sectionalizing.The content of the chapter one introduces the research status of UPFC and lowfrequency oscillation, then it analyzes the mathematical model and the work priciple ofUPFC. Expounding the influnce to transmission capacity adjusting the distribution of flowand reinforceing the transient stability of system. Indicating the mechanism of lowfrequency oscillation, the main reason is the emergence of negative damping and theforced power oscillation. Indicating the controlling steps. On the basis of it, analysising theworking range of shunt side converter and serise side converter, building control system ofshunt side and serise side,regulating output voltage to containing the system flow and nodevoltage. Discussing the influnce to system damping after switching in UPFC,designingsubcontrol to make better the ability to damping oscillation. To improve the capability ofcontrolling system flow, and the ability of damping low frequency oscillation when systemshort circuit fault and change in load.