A novel approach for analytical modeling of line commutated converter based HVDC systems for electromagnetic transient analysis

A novel approach is used to derive a completely analytical model of a six pulse line commutated converter based HVDC system. The system is split into two subsystems and is then solved individually. Therefore each period of a subsystem is divided into six intervals. Hence it is only necessary to solve one period analytically for the state of commutation as well as for the state of two-valve conduction. All other solutions are then deduced from the original solution with a simple rotation. Afterwards the subsystems are connected and the dependencies of each other are taken into consideration. The space vector transformation is used to split the system into independent subsystems (two for the state of commutation and one for the state of two-valve conduction), which allows to obtain a closed form solution. Accuracy of the model is approved by comparison with electromagnetic transient models.