Electromagnetic transient simulation with state variable representation of HVDC conversion
Thesis DisciplineElectrical Engineering
Degree GrantorUniversity of Canterbury
Degree NameDoctor of Philosophy
This thesis describes an accurate and efficient method for transient simulation of HVdc/ac power systems. An overview of existing transient simulation methods for power systems, with special emphasis on HVdc converter plant, is made, and their main features outlined. The two alternatives in current use, Electromagnetic Transient Programs and State Variable Analysis, are given special consideration. The first method while being efficient and flexible suffers from numerical oscillations when simulating switching components, requiring remedial methods which reduce its effectiveness. The latter method while producing stable and accurate simulation of switching devices, results in inefficient computation for practical ac system sizes. A hybrid algorithm is proposed which combines the efficiency and flexibility in system representation of the Electromagnetic Transient Simulation programs and the accuracy of the state variable programs to handle HVdc converter non-linearities. The hybrid method is applied to several test systems and the performances are compared with those of an Electromagnetic Transient program. The proposed method is applicable to any ac/dc power system, with single or multiple non-linearities.