Simulation of a 5-terminal HVDC configuration between Eastern and Western Europe

Investigations have been made into how the AC networks in eastern Europe can be coupled together with the UCPTE system so that energy exchange between the existing interconnected systems will become possible. In order to study the performance of a DC interconnection, a simulation model of a bipolar 5-terminal HVDC system was developed. The calculation model was used for studies of the system stability of the connected AC networks which is substantially influenced by the reaction of the DC link. One major demand was that it should be possible to study also DC faults in detail which normally is not possible with conventional stability programs, where the DC transfer functions are represented only in a simplified manner. For this reason an improvement in the simulation program was made that allows stability calculation of large AC networks using complex admittances and parallel solution of the differential equations in the DC circuit. With this new method for stability studies, accurate transient behavior of the DC quantities can be obtained. In the following, the calculation model is referred to as “Advanced Stability Model” (ASM). After an overview at the system configuration some economic aspects are discussed and a description of the HVDC multiterminal configuration is given. Then the ASM is discussed and comparisons with a detailed commutation model of the multiterminal HVDC are shown in order to demonstrate the performance and the accuracy of the ASM. In the last section, some relevant simulation results of the multiterminal configuration are presented.