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49-627: In the winter of 1998, Québec's power lines were toppled by icing , sometimes up to 75 mm. To prevent such a damage, a de-icing system was developed. The Levis De-Icer can use a maximum power of 250 MW; its operation voltage is ±17.4 kV. It can be used on multiple 735 kV AC power lines . When there is no icing, the Lévis De-Icer installed at Hydro-Québec 's Lévis substation 46°42′17″N 71°11′39″W  /  46.70472°N 71.19417°W  / 46.70472; -71.19417 , south of Quebec City operates as static VAR compensator improving

98-422: A silver storm , is a type of winter storm characterized by freezing rain . The U.S. National Weather Service defines an ice storm as a storm which results in the accumulation of at least 0.25-inch (6.4 mm) of ice on exposed surfaces. They are generally not violent storms but instead are commonly perceived as gentle rains occurring at temperatures just below freezing. The formation of ice begins with

147-605: A closed loop between each phase. According to Chris Horwill (AREVA T&D) there are four main design ratings in the de-icer mode. The first one is the Standard de-icer mode. It works at 250 MW and 7200 A from ±17.4 kV at 10 °C. The second one is the Verification mode. It works at 200 MW and 5760 A from ±17.4 kV at 30 °C. The third one is the 1-hour overload. This one works at 300 MW and 7200 A from ±20.8 kV at 10 °C. The last one

196-404: A few hours and leaves a few millimeters (fractions of an inch) of accumulation. It renders roads and sidewalks slippery, causing minor traffic collisions, but road crews use de-icing material to take care of it. Power lines and other equipment are built according to tough standards, since large accumulation events have happened many times prior to 1998. In Quebec, standards were reinforced after

245-408: A layer of above-freezing air above a layer of sub-freezing temperatures closer to the surface. Frozen precipitation melts to rain while falling into the warm air layer, and then begins to refreeze in the cold layer below. If the precipitate refreezes while still in the air, it will land on the ground as sleet . Alternatively, the liquid droplets can continue to fall without freezing, passing through

294-514: A lot of reactive support. It would take a significantly higher amount of voltage to push the necessary current through the line. The high voltage power transmission system in Quebec runs in two transmission corridors, one high voltage system runs in the north-west from the main load centres of Montreal and Quebec and the other runs north-east along the Saint-Lawrence river. It is the latter corridor that

343-460: A phase to melt 12 mm of radial build-up of ice. The dc converter at Lévis will be used to de-ice 5 lines: four 735 kV single-circuit lines and one 315 kV double-circuit line. Because of the different lengths and sizes of the conductor, the dc installation needs to be able to operate in various voltages and currents. To be de-iced, the transmission line needs be isolated from the ac circuits at both ends. Line conductors are used to form

392-461: A storm left 30 millimetres (1.2 in) to 40 millimetres (1.6 in) of ice in Montreal in 1961. Prior to the 1998 storm, the last major ice storm to hit Montreal (1961) deposited around 30 to 60 millimetres (1.2 to 2.4 in) of ice. However, the 1998 storm left deposits twice as thick, downing power lines all over the region, damaging most of the trees in Montreal, and leaving streets covered in

441-620: A thick, impassable layer of ice. On January 4, 1998, an upper level low system stalled over the Great Lakes , pumping warm and moist air from the Gulf of Mexico toward the upper St. Lawrence Valley. The upper flow then turned eastward, bringing this air mass down toward the Bay of Fundy . At the same time, a high pressure center was sitting farther north in Labrador , keeping an easterly flow of very cold air near

490-602: Is 7200 Adc, defines at an ambient temperature of +10 °C. The current rating is too high for a single converter bridge based on present-day HVDC technology. However, with two converter bridges in parallel, the required dc current per bridge can be met with 125 mm thyristors used in HVDC converters. With two thyristor converters connected in parallel, there are several possible circuit topologies. The three main alternatives considered were: Twelve Pulse Circuit, Double Twelve Pulse Circuit, Double Six Pulse Circuit. In this circuit,

539-476: Is easily capable of shutting down entire metropolitan areas. Additionally, the loss of power during ice storms has indirectly caused numerous illnesses and deaths due to unintentional carbon monoxide (CO) poisoning . At lower levels, CO poisoning causes symptoms such as nausea , dizziness , fatigue , and headache , but high levels can cause unconsciousness , heart failure , and death. The relatively high incidence of CO poisoning during ice storms occurs due to

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588-476: Is mainly in an area prone to ice storms that deposit ice on the transmission lines. The selected power transmission line is configured for de-icing mode after being isolated from its respective circuit. A de-icing circuit is created by a set of disconnect switches controlled by the DCU which connects the transmission line to the de-icing converter. The DC power is slowly increased to reach the desired level of current. Once

637-452: Is the Low ambient overload. It works at 275 MW and 7920 A from ±17.4 kV at −5 °C. The range of operation of the current and voltage is large because all of the sections have different characteristics. In "de-icer" mode, the installation provides a controlled high current of dc (direct current) power source which feeds a resistive load. The normal current rating in the de-icer mode

686-874: Is the Target voltage. It is at 315 kV±5%. The third one is just the Slope. And the last one is 3% on MVAr. January 1998 North American ice storm The North American Ice Storm of 1998 (also known as the Great Ice Storm of 1998 or the January Ice Storm ) was a massive combination of five smaller successive ice storms in January 1998 that struck a relatively narrow swath of land from eastern Ontario to southern Quebec , New Brunswick and Nova Scotia in Canada, and bordering areas from northern New York to central Maine in

735-466: Is to understand the long-term effects of the prenatal exposure to stress on the physical growth and functioning, cognitive development, and behaviour of the Project Ice Storm children by studying developmental trajectories through age 13. 45°07′N 73°40′W  /  45.11°N 73.67°W  / 45.11; -73.67 Ice storm An ice storm , also known as a glaze event or

784-477: The Appalachian Mountains . Snow is produced at upper levels in such a winter storm system, but it eventually melts into rain as it falls through a warm air layer of above-freezing temperature (of at least 1,200 feet (370 m) in-depth) associated with the overrunning. The rain passes through colder air near the surface and is supercooled . When that rain touches the ground or any other cold surface in

833-564: The downtown core were cordoned off by police due to the dangers of large sheets of ice falling from buildings. The area south of Montreal ( Montérégie ) was so affected that the triangle formed by Saint-Hyacinthe , Granby and Saint-Jean-sur-Richelieu was nicknamed the triangle noir ("dark or black triangle") by the French-language media, and the Triangle of Darkness in English media, for

882-402: The "Inter-Phase Transformer" is eliminated because the emf produced by the bridges is the same. The step-down transformer, like in the twelve pulse circuit, is also complex, along with the thrystor valves and their interconnecting busbars. This is a simple connection between two six-pulse thyristor bridges. The de-icer function can be achieved with only a two-winding step-down transformer. Unlike

931-653: The United States and the Canadian Forces, to help restore power to affected homes in eastern Ontario and western Quebec. Roughly 700,000 of Maine 's 1.2 million residents were without electricity, the Maine National Guard was mobilized, and hundreds of utility crews from as far away as North Carolina arrived to help. With 8 deaths, this became the deadliest natural disaster in Maine history. Three weeks after

980-405: The United States. It caused massive damage to trees and electrical infrastructure throughout the area, leading to widespread long-term power outages. Millions were left in the dark for periods varying from days to several weeks, and in some instances, months. It led to 34 fatalities, a shutdown of activities in large cities like Montreal and Ottawa , and an unprecedented effort in reconstruction of

1029-527: The actions required for de-icing each line in order to provide network security and ensure the de-icing sequences are reliable. The current passing through the conductor needs to be just high enough to melt the ice on it without exceeding the thermal limit of the conductor. A 735 kV transmission line with a bundle of four 1354  MCM conductors for each phase, requires a de-icing current of 7200 A per phase. At −10 °C and wind velocity at 10 km/h, it would take 30 minutes of current injection on

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1078-413: The cold air below, the droplets freeze on contact, creating accumulations of ice. If the cold air layer is too thick, the droplets refreeze before hitting the ground and form ice pellets , which are usually less hazardous. The Montreal area typically receives freezing rain between 12 and 17 times a year, averaging between 45 and 65 total hours of rain. However, a freezing rain storm usually lasts only

1127-416: The cold air just above the surface. This thin layer of air then cools the rain to a temperature below freezing (0 °C or 32 °F). However, the drops themselves do not freeze, a phenomenon called supercooling (or forming " supercooled drops "). When the supercooled drops strike ground or anything else below 0 °C (32 °F) (e.g. power lines, tree branches, aircraft), a layer of ice accumulates as

1176-725: The cold water drips off, forming a slowly thickening film of ice, hence freezing rain. While meteorologists can predict when and where an ice storm will occur, some storms still occur with little or no warning. In the United States, most ice storms occur in the northeastern region , but damaging storms have occurred farther south; an ice storm in February 1994 resulted in tremendous ice accumulation as far south as Mississippi, and caused reported damage in nine states. The freezing rain from an ice storm covers everything with heavy, smooth glaze ice . In addition to hazardous driving or walking conditions, branches or even whole trees may break from

1225-400: The electrical grid had to be undertaken. With many roads impassable due to heavy snowfall or fallen trees, broken power lines and coated with a heavy layer of ice, emergency vehicles could hardly move. On January 7, the provinces of New Brunswick, Ontario, and Quebec requested aid from the Canadian Forces (CF), and Operation Recuperation began on January 8. Over 15,000 troops were deployed. It

1274-418: The end of the ice storm, there were still thousands of people without electricity. In Quebec alone, 150,000 people were without electricity as of January 28. Estimates of material damage reached around $ 2 billion Canadian for Quebec alone. Overall estimates are around $ 4–6 billion US$ for all the areas affected. Damage to the power grid was so severe that major rebuilding , rather than repairing, of

1323-435: The equipment’s state to the operator in order to continue the process as there is always a chance of communication failure. Flexible stimulation sequences used for control logic and MMI validation, pre-operational testing and operator training are required for line equipment and SVC. For 735 kV lines, de-icing takes place in three steps while 315 kV double circuit lines only need one. A DCU supervises and coordinates all

1372-605: The flooding farther south from the same storm system. The bridges and tunnels linking Montreal with the South Shore were closed because of concerns about weight tolerances or ice chunks falling from the superstructures. All but one power linkage to the island of Montreal were down for several days, disabling both of the city's water pumping stations. When power was restored, parts of Montreal remained impassable due to large chunks of ice falling from rooftops, which endangered pedestrians and motorists; large portions of Old Montreal and

1421-466: The ice off the conductors. However, because the operation in this mode may be very infrequent, when the installation is not being used for deicing, it is used as a Static Var Compensator, SVC for short, by using the HVDC valves as a Thyristor Controlled Reactor. An innovative design is used, minimizing the power losses of the valves in SVC mode. The reason alternating current wasn't used was because AC would require

1470-524: The line has been de-iced, the de-icing disconnect switches are opened and the DCU then releases the line back to the AC network. The line to be de-iced must stay in normal operation during the entire period of DCU development and start-up. The final installation of the SVC/de-icer requires a de-icing line equipment pre-operational testing before being installed. This system is rarely used, only for critical conditions as

1519-402: The logistical support required to sustain the operation. Project Ice Storm ( Projet Verglas ) was created to monitor the long-term effect of prenatal stress . Researchers at McGill University set up the project in the immediate aftermath of the disaster, finding 178 families to participate; some of the women were still pregnant at the start of the investigation. "The goal of the current study

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1568-425: The operators would be under heavy stress and the man-machine interface (MMI) must be on guided mode. For the five transmission lines equipped for de-icing, there are 13 line topologies which have between 40 and 90 actions per line to be performed during the de-icing process. Out of the five lines, four have three de-icing circuit topologies and the last only has one. The DCU must offer the possibility to manually confirm

1617-462: The other two, this circuit can simple controller because the two thyristor bridges can be triggered directly in parallel. As a result, this circuit produces a broader range of harmonic currents and voltages. According to Chris Horwill, there are also four main design ratings in the SVC mode. The first one is the Dynamic range. This one is at 225 MVAr, or −115 MVAr at nominal voltage. The next one

1666-521: The power grid. The ice storm led to the largest deployment of Canadian military personnel since the Korean War , with over 16,000 Canadian Forces personnel deployed, 12,000 in Quebec and 4,000 in Ontario at the height of the crisis. Freezing rain is common in the eastern half of Canada and New England , generally occurring at the narrow boundary between cold air from the east and north and moist air from

1715-539: The request of the Province of Quebec, CF members assumed the powers of peace officers in the most devastated areas around Montreal. At the height of this crisis, Operation Recuperation involved 15,784 deployed personnel (including 3,740 Reservists) from all three CF commands: 10,550 in Quebec, 4,850 in Ontario and 384 in New Brunswick. In addition, 6,200 CF members and DND employees working at their regular jobs provided

1764-402: The rest were damaged to different degrees and had to be trimmed, a large number severely. Critically, about 1,000 steel electrical pylons and 35,000 wooden utility poles were pulled over by the weight of the ice, further damaging the power supply and hampering the return of electricity. Teams were brought in from places such as Prince Edward Island and Nova Scotia , along with teams from

1813-472: The sick, shelter and feed about 100,000 people frozen out of their homes, and ensure that farmers had the generators and fuel required to keep their operations going. CP-140 aircraft from 14 Wing Greenwood, NS , conducted aerial imagery of the downed power lines in Quebec and Ontario. Military engineers and technicians worked around the clock with hydro and telephone crews to repair and replace downed transmission towers and utility poles. On January 13, at

1862-752: The south, southern Ontario and western New York, as well as much of the Appalachian region from Tennessee northward, received heavy rain and severe flooding, while further east, the Canadian Maritimes mostly received heavy snow. Exacerbating the problem was a steep drop in temperature that immediately followed the passage of the freezing rain, which combined with the extreme power outages led to numerous indirect deaths due to carbon monoxide poisoning from generators and other sources as people desperately tried to remain warm. Many power lines broke and over 1,000 transmission towers collapsed in chain reactions under

1911-608: The south. Typically, a warm air mass will travel northward along the Mississippi Valley and overrun a shallow layer of cold air trapped at the surface. Such a favorable cold air damming happens with an east to northeasterly flow in the St. Lawrence (the predominant wind direction in the St. Lawrence Valley is usually either northeast or southwest) and the Ottawa Valley and along the axis of

1960-427: The stability of the AC lines. The North American ice storm of 1998 resulted in many of Hydro Quebec's transmission towers collapsing as a result of excessive ice buildup on conductors. To ensure that similar events wouldn't happen again, Hydro-Québec TransEnergie created a De-icing system for their transmission lines . The De-icing system runs a high direct current (DC) into a selected transmission line in order to melt

2009-826: The surface. An unusually strong Bermuda high pressure area was anchored over the Atlantic Ocean, which prevented these systems from moving further to the east, as most winter storms do when they pass over the Great Lakes–St. Lawrence region. A series of surface low pressure systems passed in this atmospheric circulation between January 5 and January 10, 1998. For more than 80 hours, steady freezing rain and drizzle fell over an area of several thousand square miles of Eastern Ontario , including Ottawa, Brockville , and Kingston , an extensive area in southern Quebec, northern New York , and northern New England (including parts of Vermont , New Hampshire and Maine ). Farther to

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2058-545: The total lack of electricity for weeks. Cities such as Ottawa , Smiths Falls , and other Eastern Ontario municipalities, that had never experienced such an amount of freezing rain, declared a state of emergency. On January 7, Ontario, Quebec, and New Brunswick called on the help of the Canadian Forces , prompting the deployment of more than 15,000 military personnel at the peak of the crisis. In addition to help residents, CN locomotives (CN3502 and CN3555) were moved off

2107-450: The tracks and used to provide power to residents of Boucherville and Coteau-du-Lac , south and west of Montreal respectively. A third locomotive was moved to Boucherville, but never actually put to use. The loss of electrical power also greatly affected pig and cattle farmers, as they could no longer provide water or adequate ventilation to their barns full of livestock, leading to the death of many animals. Many barns also collapsed under

2156-485: The two bridges are fed from separate windings of the step down transformer. To improve harmonic cancellation, they have a 30° phase shift between them. Since the two bridges are connected in parallel, a specialised "Inter-Phase Transformer" is required to balance the differences in their emf. Also, this system requires a complex, multi-winding, step-down transformer. In this circuit, two whole, 12 pulse bridges that are series-connected, are connected in parallel. For this one,

2205-541: The use of alternative methods of heating and cooking during prolonged power outages, common after severe ice storms. Gas generators, charcoal and propane barbecues, and kerosene heaters contribute to CO poisoning when they operate in confined locations. CO is produced when appliances burn fuel without enough oxygen present, such as basements and other indoor locations. Loss of electricity during ice storms can indirectly lead to hypothermia and result in death. It can also lead to ruptured pipes due to water freezing inside

2254-564: The weight of ice. Falling branches can block roads, tear down power and telephone lines, and cause other damage. Even without falling trees and tree branches, the weight of the ice itself can easily snap power lines and also break and bring down power/utility poles; even electricity pylons with steel frames. This can leave people without power for anywhere from several days to a month. According to most meteorologists , just 0.25-inch (6.4 mm) of ice accumulation can add about 500 pounds (230 kg) of weight per line span. Damage from ice storms

2303-463: The weight of the ice, killing the animals trapped inside. Millions of trees were brought down by the weight of ice around the affected areas. With many trees damaged or felled by the heavy ice, the maple syrup and orchard regions suffered heavy blows and massive losses in the storm; Quebec's maple sugar industry, the largest in the world, was devastated. As another example, 5,000 trees in Montreal's Mount Royal Park had to be cut, 80% (140,000) of

2352-423: The weight of the ice, leaving more than 4 million people without electricity, most of them in southern Quebec , western New Brunswick and Eastern Ontario , some of them for an entire month. At least twenty-five people died in the areas affected by the ice, primarily from hypothermia , according to Environment Canada . Twelve more deaths and hundreds of millions of dollars in additional damage were caused by

2401-484: Was the largest deployment of troops ever to serve on Canadian soil in response to a natural disaster since the Manitoba floods in 1997 , where 14,000 troops were deployed, and the largest operational deployment of Canadian military personnel since the Korean War . CF members from about 200 units across Canada helped provincial and municipal workers clear roads, rescue people and animals trapped by storm wreckage, evacuate

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