Planned Voltage Reduction Test – July 18, 2023

July 5, 2023

GrandBridge Energy has been advised by the Independent System Operator (IESO) that a system voltage reduction test is scheduled for Tuesday, July 18, 2023, as part of mandatory testing of its emergency operating measures.  The province-wide test will consist of two voltage reduction exercises of approximately one hour each in duration.

A three (3) per cent reduction is expected to occur from 9:00 EST to 10:00 EST. A five (5) per cent reduction is planned for 13:00 EST to 14:00 EST. These tests are normally conducted every 18 months.

What is a voltage reduction?

A voltage reduction is one tool used by the IESO to manage the reliability of Ontario’s power system when demand for electricity exceeds available supply. The IESO performs voltage reduction tests to simulate emergency actions and to measure the load reduction resulting from voltage reductions. Voltage reductions lower demand quickly and minimize the likelihood of service interruptions, helping the IESO maintain the reliability of Ontario’s power system during a variety of unplanned occurrences.

What is the impact of a voltage reduction on consumers?

Most consumers will not notice voltage reductions, as supplied voltages are still expected to be within established industry standards for electrical equipment used by residential and commercial consumers. Voltage reductions have been performed in the past, as part of the IESO’s routine testing protocols and, under extreme circumstances, to prevent blackouts. If you have not noticed any impact on your equipment in the past, you should not notice it during this test.

Additional information about the IESO voltage reduction test can be found on the IESO’s website www.ieso.ca.

Customers with questions about the IESO voltage test can contact our Customer Service team Monday to Friday from 8:30 am to 4:30 pm.