Investigations into the Optimization of Conductor Connectors for Plastic-Insulated High-Voltage Cables (HVAC & HVDC) of Large Cross-Sections Using the Finite Element Method

Due to the limited transportable length of power cables, especially with large conductor cross-sections, it is necessary to connect several cable sections to cover long distances. Today, mostly screw connectors are used for such connections. It is not sufficiently known how to connect optimally the conductor ends in order to achieve a long lasting reliability of the connection system and thus the availability of the entire cable route. For this reason, it makes sense to optimize the cable connectors in such a way that transmission reliability is guaranteed. In order to achieve this, it is necessary to simulate the contact behaviour of different conductor constructions in a screw connector with regard to its transmission resistance, the current densities occurring, and the resulting power dissipation. Preliminary investigations have been carried out with the objective to understand the behaviour of an existing screw connector for MV (Medium Voltage) cables based on FEM (Finite Element Method) simulations. Main questions have been how the current density behaves in a standard connector and how the current density distribution can be optimized by changing the screw position, number, size and torque. The second step has been to investigate the transmission behaviour of connector for Single-Core (SC) conductor in detail. For this purpose, FEM simulations and practical measurements, based on e.g. the VDE (German: Verband der Elektrotechnik, Elektronik und Informationstechnik) standard are used to determine and compare the transmission resistance of a conductor connection with a standard connector. Based on these investigations, it shall be determined which factors are decisive for the optimization of such a connection.