The Independent Electricity System Operator (IESO) will conduct a routine voltage reduction test on Tuesday, January 21, 2025 as part of mandatory testing of its emergency operating procedures. This province-wide test will have minimal noticeable impact on the public at large.
The test will consist of two reductions in voltage:
- A three per cent voltage reduction will occur from 9:00 – 10:00 EST
- A five per cent reduction from 13:00 – 14:00 EST.
These tests are normally conducted every 18 months. If you did not notice any impact on your equipment during past tests, you should not notice it during this test.
Ensuring a reliable grid
Voltage reduction is an emergency action available to the IESO to maintain reliability in situations when demand on the power grid exceeds the available supply. Voltage reductions can lower demand quickly, minimizing the likelihood of service interruptions. Voltage reductions have minimal or no noticeable impact on the general public as the voltages are still expected to be within established industry standards for electrical equipment used by residential, commercial and industrial consumers.
The purpose of voltage reduction tests is:
1. To determine how much power can be reduced through the two levels of reduction.
2. To identify equipment problems so they can be addressed.
3. To help keep IESO and market participant staff familiar with procedures and identify any deficiencies in the procedures that may need correction.
For more information
The IESO is responsible for managing Ontario’s bulk electricity power system and operating the wholesale market. More information about their services can be found at www.ieso.ca.
Additional information about the voltage reduction test can be found on the IESO’s website at https://www.ieso.ca/en/Sector-Participants/System-Reliability/Voltage-Reductions
