Electric and Thermal Stress Analysis of a HV Insulation System Acc. to IEC 60034-18-42 for a Hydro Generator with Different Inverter Technologies

Abstract

This paper investigates the aging behavior and lifetime performance of full-size stator and rotor bars subjected to realistic inverter voltage stress. A dedicated high-voltage test setup combining an AC transformer and a bipolar square-wave generator is used to simulate voltage waveforms representative of modern inverter topologies, including voltage source inverters (VSI) and modular multilevel converters (MMC). The results enable a comparative evaluation of insulation systems used in DFIM rotor bars and CFSM stator bars under different converter technologies.