Master Thesis – Transformer Overloading Capacity

Vattenfall R&D is responsible for conducting business driven technical development that creates value for the company and helps us realize our strategy. We develop cost-effective, safe & sustainable solutions to improve the infrastructure of Vattenfall assets including Hydro, Wind, Nuclear, SKB, Heat and Distribution.

Thesis background/subject 

Overloading transformers (over 150MVA – 500MVA) beyond its design capacity or designing transformers for higher capacity than needed are common practices within the wind industry. Decisions related to both options depend on several factors like the repair time, probability of failure, etc. ​ Additionally, there is also an impact on the revenue and transformer's lifetime.​

This thesis consists of:

• Conducting a literature review.
• Developing a standard overloading cycle from examples in IEC60853 & IEC 60076-7.
• Making an excel or python-based tool to calculate the impact of Transformer overloading on temperature rises (for example use annex B & C of IEC 60076-7).
• Providing an assessment of CAPEX (considering weight aspects) Vs revenue loss.

Based on the thesis results, we will be able to operate wind farm transformers more efficiently and reduce the loss in revenue. Also, our decision-making process will benefit from a better understanding of the costs and benefits of overloading transformers. In this way, we will favor the optimization of wind farms business cases, which will have positive effects on the energy transition.

Objective/Purpose

The ultimate goal is to gain understanding of the benefits and impacts of transformer overloading.

• This assignment is for 1 student