Ice Melting & Ice Rolling

Preventing power outages

Colorado lows and Alberta clippers often bring extreme and fluctuating weather conditions, including high humidity and below-freezing temperatures.

When these weather conditions strike, we strike back by removing ice from power lines as quickly as possible to prevent equipment breakage and loss of power.

What would happen if the ice wasn't removed?

Ice weight can put a lot of stress on power lines and damage equipment. In windy conditions, icy lines can whip violently and gallop, causing tie wires to break, wood poles to snap, and even steel towers to crumple.

See video of galloping power lines (open new window).

Ice Removal Techniques

• Ice melting: Power is cut to a certain section of lines, and the customers serviced by those lines, for 1–3 hours. A controlled short-circuit is placed at one end of a sub-transmission line. The current flow creates a gradual temperature increase that heats up the line and melts the ice. Melting can only be done when the outside temperature is –7 C or higher.

  Ice melting may require us to shut off the power to certain customers, but it's a short-term outage that can help prevent significant equipment damage resulting in longer outages. Using 2 crews of 3–4 people each (one crew working outside on the equipment and the other crew working in a control room), we can melt the ice off 30–50 kilometres of line in about 3 hours.

  We developed the ice melting process over 30 years ago and we're recognized as leaders in the field. Our expertise is often called on by other regions experiencing ice emergencies, such as the 1998 ice storm that paralyzed eastern Canada.

• Ice rolling: A roller, attached to the end of a long pole or rope, is hung onto a conductor. In windy or wet weather, the power is turned off; in some weather conditions, it can be left on. The roller is pulled along the power line, cracking the ice off as it goes.

  Manitoba Hydro crew rolling ice off power lines near Minnedosa.

  This is a labour-intensive, manual procedure, often done in freezing rain and storm conditions. Rolling is done when melting is not an option. A 10-person crew can de-ice roughly 1.6 kilometres of line per hour.

Whether we melt or roll ice depends on

• current temperatures;
• weather conditions;
• the amount of ice buildup;
• location;
• our ability to isolate selected lines.

Learn more about power outages and how to be prepared for a power outage.