Julie Zambrano

Automatic Under Frequency Load Shedding and Islanding, as any other protection scheme could fail, leading to a blackout. In general, the failures are related to implementation and setting update issues, but frequency calculation algorithm and how is frequency being measured also affect the scheme performance, resulted in partial or total loss of the system load.

 Since frequency is obtained from voltage, there are two aspects to consider: which voltage phase o combination of it is used as a reference for calculation and where the relay is located, because local voltage is affected by transient phenomena that may occur in the system and each phase and busbar is not affected equally. Therefore, depending on the manufacture of the relay, different responses can be obtained with the same settings, due to during major events not just frequency but voltage vary, and power oscillations could happen, affecting the right disconnection of the corresponding load set.

Biography:

Electrical engineer with experience in the operation and simulation of electrical Power systems and protection systems. In 2008. She obtained a master’s degree in electrical engineering, and in 2015, she completed a Diploma in Protection Systems.

Julie spent nearly a decade between supporting the activities in the Control Center, in Caracas, and working as protection engineer, for the maintenance area.

Currently, Julie works as Protection Engineer, where she performs power flow, short circuit and coordination studies. At the end of 2022, Julie published her first book: Analysis of Failures in Power Systems.