Degree Name

BS in Electrical Engineering


Electrical Engineering Department


Ali Shaban


The objective of this Senior Project is to use the SEL 387 current differential and overcurrent microprocessor relays to protect three-single-phase 1 KVA 120:208 transformers configured in ∆-∆, Y-Y, Y-∆, and ∆-Y connections. In the second phase of this project, is to create a functioning lab that uses the SEL 587 relay to teach basic differential transformer protection for the upcoming EE-444 students.

The protection schemes developed in both of the senior project phases require the use of differential and overcurrent protection elements by monitoring the changes of the input and output current through the transformer. When these currents fail to match, in the case of a fault, or reach a specified current set point, the relay must trip. Experimentally, these differential protection schemes will be tested by flipping the polarity of the currents going into the relay to simulate an internal fault in the transformer. Afterwards, the event report generated by the relay will be analyzed to verify the results. Because of safety limitations regarding circuit breakers, the overcurrent element will not be tested in this senior project.

The EE-444 lab will follow the same design and test procedure for the first phase of the senior project. However, the lab will use the SEL 587 in place of the SEL 387, the same 3 KVA transformers on the lab bench, and will only test the differential protection for the Y-Y transformer configuration.