At the CIGRE Southern Africa 2023 Conference Ian Gray presented a paper on his experience related to the issues on the lack of reliability of these LV-GSUs.
Ian Gray(MSAChem I No 51954)
As we start to see a lot of new applications for transformers due to the worldwide energy transition process.
It starts with the massive expansion of photovoltaic and wind energy plants, thus today an additional installed energy capacity of around 2.500 GW worldwide has been reached. Therefore, these transformers are designated as Lower Voltage Generator Step-Up Transformers (LV-GSUs). Moreover, usually these LV-GSUs are in comparison to conventional GSUs highly stressed by fluctuating loads and in addition by harmonics, because they are often fed by inverter-systems instead of generator sets.
In the last decade several failures on such LV-GSUs have been reported and leading to the assumption that they are less reliable than the conventional large GSUs.