IEEE C57.12.23-2018

This standard covers certain electrical, dimensional, and mechanical characteristics and takes into consideration certain safety features of single-phase, 60 Hz, liquid-immersed, self-cooled, submersible distribution transformers with separable insulated high-voltage connectors. These transformers are rated 250 kVA and smaller, with high voltages of 34 500 GrdY/19 920 V and below and with low voltages of 600 V and below. These transformers are generally used for step-down purposes from an underground primary cable supply. These transformers are typically installed in an enclosure below ground level, operated from above and suitable for continuous submerged operation.