IESO proposes to update its synchrophasor data requirements to include storage resources as part of its effort to expand the use of phasor measurement units (PMUs) in Ontario. 

Storage units rated at least 20 MVA, including aggregations, would be required to provide their voltage and current phasor measurements and frequency for all three phases. The same requirement would apply to units that are associated with or have the potential to impact a NERC interconnection reliability operating limit, regardless of size. 

The data required would be the same as those provided by generators and transmission owners, but the ISO also proposes doubling the reporting rate — 60 samples per second — for all resources. Storage units also would need to provide phasor measurements for each phase sequence, unlike generation and transmission, which must provide data for only the positive sequence. 

The number of PMUs grew exponentially in North America after the 2003 Northeast blackout. The American Recovery and Reinvestment Act of 2009 (the so-called “stimulus package”) provided $4.5 billion for grid operators to deploy smart grid technologies, including PMUs. Utilities and RTOs installed more than 1,000 production-grade PMUs over the following five years. 

But Ontario has lagged behind the U.S. The IESO proposal is part of a larger initiative to increase PMU usage throughout the province to more than 200. The requirements for generation and transmission went into effect at the end of 2024. 

“This project will enable us to finally begin closing the gap between what our neighbors have been doing for some years before us and also adopt some new applications for our control room folks,” Dame Jankuloski, IESO’s lead power system engineer, said during a webinar June 26 to present the proposal. 

Feedback on the proposal is due July 10, with the goal of Technical Panel approval by the end of the year and PMU registration beginning in early 2026.