3_HVDC-08PSCAD浙大研修班(仅供参考学习)_(1).pptVIP

Definition SCR and ESCR SCR = SCC/Pd Where SCC is the short circuit capacity Pd is the rated dc power capacity in MW ESCR = (SCC-Qcomp)/Pd Where Qcomp is the reactive compensation connected to the ac bus Definition ESCR -------------------------------------------- High 2.5 Low 1.5 – 2.5 Very Low 1.5 AC System Impacts System Strength Definitions Show Build Current controller with 12 Pulse Rect case HVDC Control Systems Basic HVDC Transmission System Id = (Vrec-Vinv / Rline) Pd = Vd * Id Vd – Id Characteristics Vd Id α = min Rectifier and inverter Constant γ =18 ΔId=.1 Pu HVDC Control Diagrams VDCOL (Voltage Dependent Current Order Limit) Overall Block Diagram Use HVDC 1 case Sources of Reactive Power AC Filters Shunt Capacitors Synchronous Condensors Static Var Compensators (SVC) STATCOM The Valve is King di/dt dv/dt Over Voltage Over Current Temperature Thank you… Questions? * HVDC Training HVDC Training Professional Power System Simulation Introduction to HVDC Seminar 周铮 July 2008 Agenda HVDC Background and History HVDC Configuration and Equipment HVDC Basic Definitions / Equations HVDC AC system requirements Basic Conversion Process Simple Conversion Demo HVDC Controls and Power Transfer PSCAD Demo HVDC Controls System PSCAD demo showing Control actions Why Use DC Transmission HVDC History 1929, 1950, 1954 Mature Technology and large worldwide interest (Show HVDC project Listings_IEEE) Smaller tower: 2 versus 3 conductors DC Lower Transmission Losses AC Line effects in overhead lines or Cables Control of Power Flow Directly Connect Areas with different freq. Or Freq Phase Control / Stability system support options Separation of Large Areas into Regions. USA blackout 2003 - did not impact Quebec Rectifier Inverter 1 Valve group 2 AC Filter 3 Converter transformer 4 DC filter 5 Ground/sea electrode or metallic 6 Receiving ac system 7