Small Signal Stability Analysis For Power System Including Thyristors

This paPer studies the problem of establishing continuous time models of devicesof High VOltage Direct Current (HVDC) and Flexible AC Transmission System(FACTS) which include power electronic elements like thyristors with discrete timecharacteristic and presenis that dynamic phasor method can be adopted to establishcontinuous time models of these devices. This modeling method is aPplicable to mostof FACTS and HVDC devices, not only to those devices including Thyristor-Controlled Reactor (TCR), such as Thyristor-Controlled Series CaPacitor (TCSC) andStatic Var Compensator (SVC), but also to those devices including converter bridge,such as HVDC device and Static Synchronous ComPenstOr (STATCOM), etc.It deduces the mathematical models of TCSC, HVDC, SVC and STATCOMdevices with the proposed method. These models have enough precision inSubsynchronous Oscillation (SSO) Problem analysis. They are adaPtable not only fOrsmall signal stability analysis, but also fOr large signal stability analysis.The paPer presents another definition of dynamic phasor, i.e., dynamic phasor. based on Park transformer and points out the relationship between dynaxnic phasorbased on Park transformer and dynarnic phasor based on Fourier coefficient which isdeflned by another person. With dynamic phasor method it deduces the mathematicalmodels of traditional power comPonents, e.g., generator and transmission line, andpoints out that these models are the same to those obtaned by Park transformer in therorm.The auhor develops the user-defined dynamic phasor models of all the abovedevices with the user-defined function of Power System Analysis Software Package(PSASP) of EPRI, China, including traditional power components such as generator,transmission line, transfOrmef, Fixed Series Capacitor (FSC), grounding reactor, etc.,and new type power devices including thyristors like TCSC, HVDC, SVC andSMCOM, thus realizes time-domain simulation for SSO large signal stabilityanalysis and realizes SSO small signal stability analysis further through thelinearization platform of PSASP.This paPer studies two TCSC study systems, a TCSC system based on IEEE FirstBenchmark Model (IEEE FBM) and a simplified Yi-Feng 500kV TCSC study system,with SSR eigenvalue analysis in the platform of PSASPfMSST. It proves the funtionof TCSC to mitigate Subsynchronous Resonance (SSR). It also analyzes the influenceof thyristor triggering algorithm of TCSC on SSR mitigation.This paPer alSo stUdies an HVDC system based on lEEE FBM, a SVC systembased on IEEE FBM and a STATCOM system based on IEEE FBM. It proves thefunction of SuPplementare Subsynchronous Damping Controller (SSDC) in the abovedevices to mitigate SSR. It also analyzes the influence of inPut signal of SSDC onSSR mitigation, tdeng HVDC as an example.