Partial core power transformer
Thesis DisciplineElectrical Engineering
Degree GrantorUniversity of Canterbury
Degree NameMaster of Engineering
This thesis describes the design, construction, and testing of a 15kVA, 11kV/230V partial core power transformer (PCPT) for continuous operation. While applications for the partial core transformer have been developed for many years, the concept of constructing a partial core transformer, from conventional copper windings, as a power transformer has not been investigated, specifically to have a continuous operation. In this thesis, this concept has been investigated and tested. The first part of the research involved creating a computer program to model the physical dimensions and the electrical performance of a partial core transformer, based on the existing partial core transformer models. Also, since the hot-spot temperature is the key factor for limiting the power rating of the PCPT, the second part of the research investigates a thermal model to simulate the change of the hot-spot temperature for the designed PCPT. The cooling fluid of the PCPT applied in this project was BIOTEMP®. The original thermal model used was from the IEEE Guide for Loading Mineral-Oil-Immersed transformer. However, some changes to the original thermal model had to be made since the original model does not include BIOTEMP® as a type of cooling fluid. The constructed partial core transformer was tested to determine its hot-spot temperature when it is immersed by BIOTEMP®, and the results compared with the thermal model. The third part of the research involved using both the electrical model and the thermal model to design a PCPT. The PCPT was tested to obtain the actual electrical and the thermal performance for the PCPT. The overall performance of the PCPT was very close to the model estimation. However, cooling of the PCPT was not sufficient to allow the PCPT to operate at the design rated load for continuous operation. Therefore, the PCPT was down rated from 15kVA to maintain the hot-spot temperature at 100°C for continuous operation. The actual rating of the PCPT is 80% of the original power rating, which is 12kVA.