Analysis of the Effect of Generator’s iron Loss on Self-excitation During Black-start

After a large-scale blackout of power system, black start is needed. Generally, a balck start resource is started up followed by a series of transformers, transmission lines and load. There is a risk of self-excitation when a long-distance transmission li ne is connected to a synchronous generator. Transient simulation is a general way to verify if self-excitation occurs during the black start process. However, little attention has been on the effect of a generator’s iron loss on self-excitation. This paper investigates the impact of iron loss of synchronous generators on self-excitation. Firstly, the model of the synchronous generator is established. The physical process of self-excitation is analyzed, and then, considering the variation in iron losses, the impact on the occurrence of s elf-excitation is analyzed. Using the PSCAD simulation software, a simulation model is constructed, and the variation in iron losses is simulated by modifying the resistance value of parallel resistors. The voltage waveforms at the generator terminal and the end of the line are observed, and the critical conditions for self-excitation are analyzed.