Applications and Challenges of On-Load Tap Changing Technology for Distribution Transformers in Scenarios with High Penetration of Distributed Energy Resources

With the continuous advancement of new energy reforms in the electric power sector, the application rate of distributed energy sources, represented by photovoltaic (PV), wind power, and biomass power generation, in distribution networks is gradually increasing. This has led to a gradual transformation of distribution networks from traditional unidirectional radial networks to active networks with highly interactive sources, grids, loads, and storage. However, this structural shift poses challenges to the voltage control of the distribution system. Due to the variability and intermittency of some new energy generation sources such as PV and wind power, issues such as voltage fluctuations, overvoltage, and voltage violations in the distribution network occur frequently, posing certain risks to safe and stable operation and power quality. Against this backdrop, On-Load Tap Changer (OLTC) technology has emerged as a mature and cost-effective means of voltage regulation, applicable in distribution networks with high penetration of distributed energy sources. This paper first briefly analyzes the working principles of distribution transformers and OLTCs, followed by a study on the application of OLTC in distributed generation. Finally, experiments demonstrate that OLTC technology remains a key method for maintaining voltage stability in distribution networks with high penetration of distributed energy sources. By dynamically adjusting the transformation ratio, it effectively mitigates voltage fluctuation issues caused by the integration of distributed energy sources, enhancing the grid’s ability to accommodate new energy.