HVDC تحليل پايداري ولتاژ و توان در حالت هاي مختلف كنترلي يك سيستم تك تزريقه

POWER / VOLTAGE STABILITY ANALYSIS OF SINGLE-INFEED HVDC SYSTEMS IN DIFFERENT CONTROL MODES

Voltage/Power stability of Single-Infeed HVDC Systems is elaborated in this paper . Analysis based on Quasi-Static Assumptions is performed with Sensitivity Analysis for best known control modes at Rectifier/Inverter side in SIF HVDC Systems. component of variables is applied for analysis. A simplified model based on fundamental component of variables is applied for analysis. With certain assumptions, Mismatch Power Flow Equations are developed and linearised around operating point and Jacobian Matrices are obtained due to stability computations. Two methods of analysis to cope with this task are presented before and motivated in this paper. Two criterion called "Voltage Stability Factor" and "Maximum Available Power" based on the mentioned methods are assessed and computed in different common control modes and results are compared. Also, Voltage/Power Stability Limits are developed based on system variables. Dynamic Simulations in order to demonstrate computational, theoretical results are fulfilled and their results are shown. Simulations are performed for two systems with relatively weak and quite strong AC networks at inverter side of HVDC link. PSCAD-EMTDC Simulator is applied for simulations. Furthermore, a simple dynamic analysis for Voltage/Power stability in power/extinction angle control mode is conducted and simulation results are shown. It is also demonstrated how an appropriate control of converters can be used to stabilize a voltage/power instability in weak systems.