Managing the Risk of Instrument Transformer Failure 2024 – 2028

We are proposing to replace around 98 instrument transformers at 12 substations to maintain safe and reliable electricity supply to customers.

This Regulatory Investment Test for Transmission (RIT-T) Project Specification Consultation Report (PSCR) identifies the need to replace 98 instrument transformers at 12 substations as the preferred solution to manage the risk that these assets will fail.

Instrument transformers are a major component of the electrical protection system that ensures electrical faults are cleared within designated times, as specified in the National Electricity Rules (NER). If an instrument transformer fails explosively, it can cause unpredictable damage resulting in harm to people, potential substation failure and consequent involuntary load curtailment for customers.