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Phần 19 KHÓA ĐÀO TẠO TÍNH TOÁN ỔN ĐỊNH VÀ ỨNG DỤNG TRÊN PHẦN MỀM PSSE CHO KỸ SƯ HỆ THỐNG ĐIỆN (Mô phỏng đường dây siêu cao áp HDVC trong tính toán ổn định động): • General Considerations• HVDC Dynamic Models HVDC Dynamic Models• Complete HVDC Model in Dynamic Studies
TRANSMISSION & DISTRIBUTION A Division of Global Power POWER SYSTEM STABILITY CALCULATION TRAINING D8 HVDC Si l ti P t 2 D ay 8 - HVDC Si mu l a ti on P ar t 2 November 26, 2013Prepared by: Mohamed El Chehaly eBook for You OUTLINE 2 OUTLINE • General Considerations • HVDC Dynamic Models HVDC Dynamic Models • Com p lete HVDC Model in D y namic Studies py eBook for You 3 GENERAL CONSIDERATIONS GENERAL CONSIDERATIONS eBook for You Introduction 4 GENERAL CONSIDERATIONS Introduction DC transmission behavior is dominated by its controls It is not practical to model the detailed dynamics of the controls because the bandwidth of these controls is far greater than that of PSS®E than that of PSS®E Each converter bridge is controlled by a local feedback loop local feedback loop These local loops work independently to maintain bridge current or voltage at maintain bridge current or voltage at desired value eBook for You Introduction 5 GENERAL CONSIDERATIONS Introduction The desired values are provided by an outer control loop that works in a outer control loop that works in a supervisory role and coordinates the action of the several converter bridges action of the several converter bridges and the AC power system eBook for You Behavior of the Brid g es and their Inner 6 GENERAL CONSIDERATIONS g Control Loops A rectifier bridge may be regarded as an adjustable voltage source forcing current through transmission system resistance di d t i tth t t an d i n d uc t ance aga i ns t th e cons t an t voltage source of the inverter eBook for You Behavior of the Brid g es and their Inner 7 GENERAL CONSIDERATIONS g Control Loops A simple current control: open-loop basis with a gain equal to DC resistance A step change in current is applied eBook for You Behavior of the Brid g es and their Inner 8 GENERAL CONSIDERATIONS g Control Loops DC rectifier is a feedback loop controller that adjusts firing delay to control the DC current to a setpoint A step change in current is applied eBook for You PSS®E Models and Control Loops 9 GENERAL CONSIDERATIONS Several PSS®E models (CDC4T CDC6T ) PSS®E Models and Control Loops Several PSS®E models (CDC4T , CDC6T … ) treat DC converter pairs as if they move instantaneousl y to their new o p eratin g y pg point when any of their input signals are changed HVDC dynamic models calculate the real and reactive power loading of the converters using steady-state converter relationships with transformer taps fixed relationships with transformer taps fixed eBook for You PSS®E Models and Control Loops 10 GENERAL CONSIDERATIONS Several models are not concerned with the PSS®E Models and Control Loops Several models are not concerned with the internal dynamic behavior of converters and DC lines and DC lines Pseudo steady - state HVDC dynamic Pseudo steady state HVDC dynamic models are not able to directly represent the mode of operation where the rectifier firing angle is not at a limit and the inverter margin angle is also not at a limit t lli lt (CDC4T CDC6T ) or con t ro lli ng vo lt age (CDC4T , CDC6T … ) eBook for You [...]... from one valve to another has not been completed before p the commutating voltage reverses across the ongoing valve E ti ti angle i t small Extinction l is too ll eBook for You Commutation failure 19 GENERAL CONSIDERATIONS Protective Actions Commutation failure eBook for You Equivalent circuit for three phase bridge converter three-phase 20 GENERAL CONSIDERATIONS Protective Actions Commutation . Considerations • HVDC Dynamic Models HVDC Dynamic Models • Com p lete HVDC Model in D y namic Studies py eBook for You 3 GENERAL CONSIDERATIONS GENERAL CONSIDERATIONS eBook for You Introduction 4 GENERAL. power transfer with coordination of rectifier and inverter current setpoints inverter current setpoints Temporary overriding of DC converter normal operating setpoints in response to disturbances. models (CDC4T , CDC6T … ) treat DC converter pairs as if they move instantaneousl y to their new o p eratin g y pg point when any of their input signals are changed HVDC dynamic models