Updates to IESO Monitoring Requirements: Phasor Data

Today, Ontario’s power system is continuously monitored in real-time by the IESO using a traditional technology called Supervisory Control and Data Acquisition (SCADA). This technology utilizes power system measurements (“data”) from all facilities connected to the IESO-controlled grid across the province every 2-10 seconds. Receiving data at this frequency, and in this manner, presents two challenges: 

  1. Data for certain system events is not obtained. This was evident on January 2019 when an event occurred in Florida that grew and propagated across the eastern interconnection, causing oscillations, including in Ontario, but was uncaptured by the SCADA.
  2. Data received is not synchronized. Without precise time stamps on each piece of data, it is not always possible to have a precise picture of the impact of system events.

Phasor technology is much more advanced than the traditional SCADA technology or conventional Digital Fault Recorders in its ability to provide real-time and/or after the fact data with greater granularity (30 samples in 1 second), accuracy and detail (“phasor data”). This aids in providing an early warning of potential system events and consistent information about actual power system conditions. In addition, it replaces traditionally used time-consuming methods to benchmark power system models and also helps to perform after-the-fact forensic work on system events more effectively. Additionally, phasor data enables implementation of a non-diverging state estimator called Linear State Estimator. Further, phasor data can provide assistance to operators in restoration of system equipment from outages or islands, and improves IESO’s ability to comply with several NERC reliability standards.

Many entities in North America have already begun implementing phasor technology as part of their system monitoring and are in the process of determining how to integrate the use of phasor data in their operation and planning activities to different degrees. The IESO proposes to update Market Rule Appendices 4.15 and 4.16 to clarify requirements for generators and transmitters to install phasor technology infrastructure and provide phasor data to the IESO. The proposed changes are intended to align with requirements in other North American ISOs and RTOs. The IESO is seeking feedback from stakeholders on these proposed updates in Market Rule Appendices 4.15 and 4.16.

Additional details on the IESO's plans to engage stakeholders throughout the process can be found in the engagement plan. All comments and enquiries on this engagement can be directed to engagement@ieso.ca

Schedule of Activities

Timing Engagement Activity Webinar Registration and Recordings

Q1, 2022

Anticipated effective date of Market Rule and Market Manual amendments


Q3-Q4, 2021

Presentation of proposed Market Rule and Market Manual amendments to Technical Panel


September 21, 2021


Engagement webinar

An update will be provided to stakeholders on the proposed Market Rule and draft market manual amendments specifying synchrophasor monitoring requirements. In response to stakeholders’ requests during prior engagement sessions, the IESO will also present qualitative benefit analysis and quantitative cost range analyses for PMUs deployment in Ontario.

Recorded Presentation
This webinar was presented during the IESO's September stakeholder engagement sessions, see full agenda for more information.

March 1, 2021

Updates to IESO Monitoring Requirements – Engagement update


December 10, 2020



IESO is seeking feedback from participants on the revised implementation plan and proposed Market Rules and Draft Market Manual

February 26, 2021: IESO Response to Stakeholder Feedback


November 19, 2020


An update will be provided to stakeholders on the revised implementation schedule for the revised monitoring requirements. The IESO will seek feedback on the proposed Rules amendments and will present and discuss the list of areas addressed by a proposed newly drafted Market Manual.

Recorded Presentation


This webinar was presented during the IESO's November stakeholder engagement sessions, see full agenda for more information.


Registration List

July 15, 2020


IESO is seeking feedback from participants on the proposed rules, requirements and implementation schedule.

IESO Response to Stakeholder Feedback


June 24, 2020


Discuss and seek feedback on proposed changes to Market Rules 4.15 & 4.16 to reflect upcoming changes to monitoring requirements to add Phasor Data for certain generators and transmitters. 

Recorded Presentation

This webinar is being presented during the IESO's June stakeholder meetings. See agenda for more information.


Registration list