View source for Hydro-Québec's electricity transmission system

{{Short description|International power transmission system centred in Quebec, Canada}}
[[File:Nercmap.JPG|thumb|300px|The two major and three minor [[North American Electric Reliability Corporation|NERC]] interconnections, and the nine NERC Regional Reliability Councils.]]
[[File:Transformateur CentraleR-B.jpg|thumb|250px|735&nbsp;kV substation near the Robert-Bourassa generating station]]

'''Hydro-Québec's electricity transmission system''' (also known as the '''Quebec interconnection''') is an international [[electric power transmission]] system centred in [[Quebec]], Canada. The system pioneered the use of very [[high voltage]] 735-[[kilovolts|kilovolt]] (kV) [[alternating current]] (AC) power lines that link the population centres of [[Montreal]] and [[Quebec City]] to distant [[hydroelectric]] [[power stations]] like the [[Daniel-Johnson Dam]] and the [[James Bay Project]] in northwestern Quebec and the [[Churchill Falls Generating Station]] in [[Labrador]] (which is not part of the Quebec interconnection).

The system contains more than {{convert|34,187|km|mi|0}} of lines and 530 [[electrical substation]]s. It is managed by Hydro-Québec TransÉnergie, a division of the [[crown corporation]] [[Hydro-Québec]] and is part of the [[Northeast Power Coordinating Council]]. It has 17 [[interconnector]]s with the systems in [[Ontario]], [[Newfoundland and Labrador]], [[New Brunswick]], and the [[Northeastern United States]], and features 6,025 [[Watt#Megawatt|megawatts]] (MW) of interconnector import capacity and 7,974 MW of interconnector export capacity.<ref name="transenergie">{{cite web|title=Hydro-Québec TransÉnergie|url=http://www.hydroquebec.com/transenergie/en/|access-date=5 March 2016}}</ref>

Major expansion of the network began with the commissioning of the 735&nbsp;kV AC power line in November 1965, as there was a need for electricity transmission over vast distances from the north to southern Quebec.

Much of Quebec's population is served by a few 735&nbsp;kV power lines. This contributed to the severity of the [[power outage]] following the [[North American ice storm of 1998]].

__TOC__

==History==
[[File:Hydro-Québec logo (1944).gif|thumb|upright=0.5|left|Hydro-Québec's first logo (1944–1960)|alt=Hydro-Québec's old logo: the red, blue and yellow coat of arms of Quebec surmounted by a beaver and featuring the words HYDRO-QUEBEC in bold and two bolts of lightning]]
The first hydroelectric stations in Quebec were built by private entrepreneurs in the late 19th century. In 1903 the first long distance high-voltage transmission line in North America was built, a 50 kV line connecting a [[Shawinigan]] powerstation to Montréal, {{cvt|135|km}} away. In the first half of the 20th century, the market was dominated by regional monopolies, whose service was publicly criticised. In response, in 1944 the provincial government created Hydro-Quebec from the expropriated [[Montreal Light, Heat & Power]].<ref name="hydro-quebec">{{Cite encyclopedia |title=Hydro-Québec |last=Bolduc |first=André |encyclopedia=[[The Canadian Encyclopedia]] |publisher=[[Historica Canada]] |date=4 March 2015 |url=https://www.thecanadianencyclopedia.ca/en/article/hydro-quebec}}</ref>

In 1963 Hydro-Québec purchased the shares of nearly all remaining privately owned electrical utilities then operating in Quebec and undertook construction of the [[Manicouagan Reservoir|Manicouagan-Outardes]] hydroelectric complex. To transmit the complex's annual production of about 30 billion kWh over a distance of nearly {{cvt|700|km}}, Hydro-Québec had to innovate. Led by [[Jean-Jacques Archambault]], it became the first utility in the world to transmit electricity at 735 kV, rather than 300–400&nbsp;kV which was the world standard at that time.<ref name="hydro-quebec" /> In 1962, Hydro-Québec proceeded with the construction of the first 735&nbsp;kV power line in the world. The line, stretching from the Manic-Outardes dam to the Levis substation, was brought into service on 29 November 1965.<ref>{{cite journal |first=Vijay K. |last=Sood |title=IEEE Milestone : 40th Anniversary of 735 kV Transmission System |journal=IEEE Canadian Review |date=Spring 2006 |pages=6–7 |url=http://www.ieee.ca/canrev/cr52/CR52_735kv.pdf |access-date=2009-03-14 }}</ref>

Over the next twenty years from 1965 to 1985, Quebec underwent a massive expansion of its 735&nbsp;kV power grid and its hydroelectric generating capacity.<ref name="IEEE40">{{cite web|url=http://www.ewh.ieee.org/reg/7/canrev/cr52/CR52_735kv.pdf|title=IEEE Milestone: 40th Anniversary of 735&nbsp;kV Transmission System|last=Sood|first=Vijay K.|date=2005-12-13|publisher=[[Institute of Electrical and Electronics Engineers]]|access-date=2008-01-10}}</ref> Hydro-Québec Équipement, another division of Hydro-Québec, and [[James Bay Energy|Société d’énergie de la Baie James]] built these transmission lines, [[electrical substation]]s, and generating stations. Constructing the transmission system for the La Grande Phase One, part of the James Bay Project, took 12,500 [[Transmission tower|towers]], 13 electrical substations, {{convert|10000|km|mi|-3}} of [[Ground (electricity)|ground wire]], and {{convert|60000|km|mi}} of [[electrical conductor]] at a cost of [[Canadian dollar|C$]]3.1 billion alone.<ref name="HQJamesBay">{{cite web|title=The James Bay Transmission System|url=http://www.hydroquebec.com/visit/virtual_visit/reseau_transport.html|publisher=Hydro-Québec|access-date=2008-01-11|archive-url = https://web.archive.org/web/20071221211846/http://www.hydroquebec.com/visit/virtual_visit/reseau_transport.html |archive-date = December 21, 2007}}</ref> In less than four decades, Hydro-Québec's generating capacity went from 3,000&nbsp;MW in 1963 to nearly 33,000&nbsp;MW in 2002, with 25,000&nbsp;MW of that power sent to population centres on 735&nbsp;kV power lines.<ref>{{Cite web|url=http://canadianeconomy.gc.ca/english/economy/1962HydroQuebec.html |title=Hydro-Québec (1962): historical context, economic impact and related links |date=2009-02-16 |access-date=2016-03-06 |url-status=dead |archive-url=https://web.archive.org/web/20090216092000/http://canadianeconomy.gc.ca/english/economy/1962HydroQuebec.html |archive-date=February 16, 2009}}</ref>

==Source of the electricity==
{{Main|List of hydroelectric stations in Quebec}}
Much of the electricity generated by Hydro-Québec Generation<ref>{{cite web|title=Hydro-Québec Generation Main Page|url=http://www.hydroquebec.com/generation/index.html|publisher=Hydro-Québec Generation|access-date=2008-01-21}}</ref> comes from hydroelectric dams located far from load centres such as Montreal. Of the 33,000&nbsp;MW of electrical power generated, over 93% of that comes from hydroelectric dams and 85% of that generation capacity comes from three hydroelectric generation centers: James Bay, Manic-Outardes, and [[Newfoundland and Labrador Hydro]]'s Churchill Falls.<ref name="IEEEConnect">{{cite journal|title=Hydro-Québec's High-Voltage Interconnections|journal=IEEE Power Engineering Review|volume=12|issue=6|pages=7|date=June 1992|first=Jacques|last=Lemay|doi=10.1109/MPER.1992.138943|s2cid=45284256}}</ref>

;James Bay
{{Main|James Bay Project}}
[[File:Déversoir, Centrale hydro-électrique Robert-Bourassa.jpg|thumb|right|The spillway of the Robert-Bourassa Dam (formerly La Grande-2 Dam), one of many hydroelectric dams supplying power to the load centres of Montreal, Quebec City, and the Northeastern United States]]
The James Bay Project encompasses the La Grande project, which is located on the [[La Grande River]] and on its tributaries, such as the [[Eastmain River]], in northwestern Quebec. The La Grande project was built in two phases; the first phase lasted twelve years from 1973 to 1985 and the second phase lasted from 1985 to present time.<ref>{{cite web|title=Geographic Location: The La Grande Complex|url=http://www.hydroquebec.com/visit/virtual_visit/index.html|publisher=Hydro-Québec|access-date=2008-01-21 |archive-url = https://web.archive.org/web/20071220212657/http://www.hydroquebec.com/visit/virtual_visit/index.html |archive-date = December 20, 2007}}</ref> In all, the nine hydroelectric dams there produce over 16,500&nbsp;MW of electric power, with the [[Robert-Bourassa generating station|Robert-Bourassa or La Grande-2 station]] generating over 5,600&nbsp;MW alone.<ref>{{cite web|title=Robert-Bourassa Generating Station|url=http://www.hydroquebec.com/generation/hydroelectric/la_grande/robert_bourassa/index.html|publisher=Hydro-Québec|access-date=2008-01-21 |archive-url = https://web.archive.org/web/20070927030051/http://www.hydroquebec.com/generation/hydroelectric/la_grande/robert_bourassa/index.html |archive-date = September 27, 2007}}</ref> In total, the project cost over C$20 billion to construct.<ref name="SEBJ">{{cite web|title=The La Grande Complex|url=http://www.hydroquebec.com/sebj/en/lagrande.html|publisher=Société d'énergie de la Baie James|access-date=2008-01-21}}</ref>

;Manic-Outardes power stations
The Manic-Outardes river area in the [[Côte-Nord|Côte-Nord or North Shore]] region consists of several hydroelectric facilities located on three principal rivers, from west to east: [[Betsiamites River]], [[Rivière aux Outardes (North Shore)|Rivière aux Outardes]], and the [[Manicouagan River]]. A single plant named Sainte-Marguerite-3 is located to the east on the [[Sainte-Marguerite River (Sept-Îles)]].<ref>{{cite web|title=Discover our Hydroelectric Facilities|url=http://www.hydroquebec.com/generation/hydroelectric/index.html|publisher=Hydro-Québec Production|access-date=2008-01-21 |archive-url = https://web.archive.org/web/20071231035513/http://www.hydroquebec.com/generation/hydroelectric/index.html |archive-date = December 31, 2007}}</ref> The facilities located in the region were constructed over a period of five decades, from 1956 to 2005. The total generation capacity from these power stations is 10,500&nbsp;MW. A 21-MW hydroelectric power station, the Lac-Robertson generating station on the [[Basse-Côte-Nord|Lower North Shore]], is not connected to the main Quebec grid.<ref>{{Cite book|author=Government of Quebec |title=Rapport d'enquête et d'audience publique – Projet de centrale hydro-électrique sur la Basse-Côte-Nord (lac Robertson) |publisher=Bureau d'audiences publiques sur l'environnement |place=Quebec City |date=May 1995 |isbn=978-2-550-12014-8 |pages=33–34 |language=fr}}</ref>
;Churchill Falls
{{Main|Churchill Falls Generating Station}}
Churchill Falls is a single underground generation station located on the [[Churchill River (Atlantic)|Churchill River]] near the town of Churchill Falls and the [[Smallwood Reservoir]] in Newfoundland and Labrador. It was constructed over a period of five to six years from 1966 to 1971–72 by the [[Churchill Falls Labrador Corporation Limited|Churchill Falls (Labrador) Corporation]] (CFLCo), though generators were installed after major construction was completed.<ref name="CFH"/> The single generation facility cost C$946 million to construct and produced 5,225&nbsp;MW of power initially after all eleven generating units were installed.<ref name="CFHSpec">{{cite web|title=Detailed Technical Specifications|url=http://ieee.ca/millennium/churchill/cf_engineering.html|first=Peter|last=Green|publisher=Churchill Falls (Labrador) Corporation and Institute of Electrical and Electronics Engineers|access-date=2008-01-21|archive-date=2008-02-14|archive-url=https://web.archive.org/web/20080214184918/http://www.ieee.ca/millennium/churchill/cf_engineering.html|url-status=dead}}</ref> A station upgrade in 1985 raised the generating capacity to over 5,400&nbsp;MW.<ref name="CFHSpec"/> Hydro-Québec Generation owns a 34.2% interest in CFLCo, which is the same company that constructed the generating plant. However, Hydro-Québec has rights to most of the 5,400&nbsp;MW of power the station produces under a 65-year [[power purchase agreement]], expiring in 2041.<ref>{{cite book |title=Shaping The Future : Annual Report 2009 |author=Hydro-Québec |location=Montreal |date=April 2010 |page=52,92 |isbn=978-2-550-58101-7 |url=http://www.hydroquebec.com/publications/en/annual_report/pdf/annual-report-2009.pdf |issn=0702-6706 |access-date=2010-04-08 |archive-url=https://web.archive.org/web/20110605082430/http://www.hydroquebec.com/publications/en/annual_report/pdf/annual-report-2009.pdf |archive-date=2011-06-05 |url-status=dead }}</ref>

{{wide image|Churchill fallslabrador.jpg|1000px|align-cap=center|View of [[Churchill Falls]], the electrical substation, and the three 735&nbsp;kV lines that span the river [[Canyon|gorge]]}}

==Electricity transmission system features==
The system contains more than {{convert|34,187|km|mi|0}} of lines and 530 [[electrical substation]]s. It is managed by Hydro-Québec TransÉnergie, a division of the [[crown corporation]] [[Hydro-Québec]] and is part of the [[Northeast Power Coordinating Council]]. It has 17 [[interconnector]]s with the systems in [[Ontario]], [[New Brunswick]], [[Newfoundland and Labrador]], and the [[Northeastern United States]] and 6,025 MW of interconnector import capacity and 7,974 MW of interconnector export capacity.<ref name="transenergie"/> The system has transmission lines reaching to power generation facilities located more than {{convert|1000|km|mi|-2}} away from population centers.<ref name="Features2"/><ref name="EPT">{{cite encyclopedia |title=Electric-Power Transmission |url=https://www.thecanadianencyclopedia.ca/en/article/electric-power-transmission |encyclopedia=The Canadian Encyclopedia |publisher=Historica Canada |date=17 July 2014 |first=M.M.C. |last=Collins}}</ref><ref name="HB"/><ref name="LPT">{{cite web|title=Power Transmission over Long Distances |url=http://www.hydroquebec.com/learning/transport/grandes_distances/index.html|access-date=2008-01-20|publisher=Hydro-Québec |archive-url = https://web.archive.org/web/20060314100546/http://www.hydroquebec.com/learning/transport/grandes_distances/index.html |archive-date = March 14, 2006}}</ref> For this reason, TransÉnergie uses a voltage of AC 735&nbsp;kV to transmit and distribute electrical power produced from Hydro-Québec's dams, although 315&nbsp;kV is used as well.<ref name="MAP2">{{cite web|title=Eastmain 1-A Powerhouse and Rupert Diversion: Area Development|url=http://www.ceaa.gc.ca/010/0001/0001/0017/Figure8-1_e.pdf|access-date=2008-01-11|author=Hydro-Québec Production|date=October 2006}} {{Dead link|date=September 2010|bot=H3llBot}}</ref> The total value of TransÉnergie's entire electricity transmission system is C$15.9 billion.<ref name="HQTE">{{cite web|title=Discover Hydro-Québec TransÉnergie and its system: Our System at a Glance |url=http://www.hydroquebec.com/transenergie/en/reseau/bref.html |publisher=Hydro-Québec TransÉnergie |access-date=2008-01-10 |archive-url=https://web.archive.org/web/20071102155606/http://www.hydroquebec.com/transenergie/en/reseau/bref.html |archive-date=2007-11-02 |url-status=dead }}</ref> For these reasons, Hydro-Québec TransÉnergie is considered to be a world leader in power transmission.<ref name="HQJamesBay"/>

===AC 735 / 765 kV power lines===
[[File:Lignes haute tension Hydro Québec.jpg|thumb|right|A Mae West pylon from a Hydro-Québec TransÉnergie 735 kV power line, recognizable by the ''x-shaped'' spacers separating the three 4-conductor sets.]]
From 1965 onwards, the 735&nbsp;kV power line became an integral part of Quebec's power transmission backbone. More than one-third of Hydro-Québec TransÉnergie's system consists of [[Extra high tension|high voltage]] AC 735 / 765&nbsp;kV power lines, totaling {{convert|11422|km|mi|0}}{{Ref label|note01|A|^}} strung between 38 substations with equipment of that voltage.<ref name="HQTE"/> The first transmission system from 1965 is an [[List of IEEE milestones|IEEE Milestone]].<ref>{{cite web|url=http://www.ieeeghn.org/wiki/index.php/Milestones:First_735_kV_AC_Transmission_System,_1965 |title=Milestones:First 735 kV AC Transmission System, 1965 |work=IEEE Global History Network |publisher=IEEE |access-date=4 August 2011}}</ref>

The physical size of the Hydro-Québec's 735&nbsp;kV transmission lines is unmatched in North America. Only two other [[utility company|utility companies]] in the same region, the [[New York Power Authority]] (NYPA) and [[American Electric Power]] (AEP) contain at least one 765&nbsp;kV line in their power system.<ref>{{cite journal|last=HOROWITZ|first=STANLEY H.|author2=HAROLD T. SEELEY|date=September 1969|title=Relaying the AEP 765-kV System|journal=IEEE Transactions on Power Apparatus and Systems|volume=PAS-88|issue=9|pages=1382–1389|doi=10.1109/TPAS.1969.292530|bibcode=1969ITPAS..88.1382H}}</ref><ref>{{cite web|title=Executive Speeches|url=http://www.nypa.gov/press/speeches/2006/60823a.htm|archive-url=https://web.archive.org/web/20060929020244/http://www.nypa.gov/press/speeches/2006/60823a.htm|url-status=dead|archive-date=2006-09-29|publisher=[[New York Power Authority]]|first=Thomas J.|last=Kelly|access-date=2008-01-11|date=2006-08-23}}</ref><ref name="AEP 765">{{cite web|title=Transmission Questions & Answers: How does the electrical system work?|url=http://www.aep.com/about/transmission/transmissionqa.htm|access-date=2008-01-11|publisher=[[American Electric Power]]|archive-url=https://web.archive.org/web/20080211145124/http://www.aep.com/about/transmission/transmissionqa.htm|archive-date=2008-02-11|url-status=dead}}</ref> However, only AEP has a significant mileage of 765&nbsp;kV power lines, with over {{convert|3400|km|mi}} of 765&nbsp;kV line traversing its broad transmission system; this system contains the most mileage in the United States under one electrical company.<ref name="AEP 765"/> NYPA has only {{convert|219|km|mi}} of 765&nbsp;kV line, all of it contained in a single direct interconnector with Hydro-Québec.<ref name="HQMAP"/><ref name="VEE">{{cite web|title=Massena Marcy 765&nbsp;kV Line|url=http://www.vanderweil.com/pu_td/pu_proj_massena.asp|publisher=Vanderweil Engineers|access-date=2008-01-11|archive-url = https://web.archive.org/web/20071020191405/http://www.vanderweil.com/pu_td/pu_proj_massena.asp |archive-date = October 20, 2007}}</ref>

The 735&nbsp;kV power line is said to lessen the environmental impact of power lines, as one single power line operating at this voltage carries the same amount of electric power as four 315&nbsp;kV power lines, which would require a [[Easement|right-of-way]] wider than the {{convert|80.0|–|91.5|m|ft|1}}<ref name="IEEE700kV">{{cite book|pages=33–43|first=Raymond|last=Lings|author2=Vernon Chartier|author3=P. Sarma Maruvada |title=Proceedings of the Inaugural IEEE PES 2005 Conference and Exposition in Africa |date=2005-07-15|publisher=Inaugural IEEE PES 2005 Conference and Exposition in Africa|doi=10.1109/PESAFR.2005.1611782|chapter=Overview of transmission lines above 700 kV|isbn=978-0-7803-9326-4|s2cid=21836196}}</ref><ref>{{cite journal|last=Hammad|first=A. E.|date=January 1992|title=Analysis of second harmonic instability for the Chateauguay HVDC/SVC scheme|journal=Transactions on Power Delivery|volume=7|issue=1|page=411|url=http://ieeexplore.ieee.org/iel3/61/3308/00108935.pdf|access-date= 2008-01-23}}</ref> width required for a single 735&nbsp;kV line.<ref name="Features2">{{cite web|title=The Development of 735-kV Transmission and Standardization at Hydro-Québec |url=http://www.scc.ca/en/news_events/features/featuresindex_26.shtml |publisher=Standards Council of Canada |access-date=2008-01-11 |date=2007-10-16 |url-status=dead |archive-url=https://web.archive.org/web/20060924165006/http://www.scc.ca/en/news_events/features/featuresindex_26.shtml |archive-date=2006-09-24 }}</ref><ref name="LPT"/><ref name="AEP 765"/> Each 735&nbsp;kV line is capable of transmitting 2,000&nbsp;MW of electric power at a distance of over {{convert|1,000|km|mi|abbr=off}} and the entire 735&nbsp;kV grid can carry 25,000&nbsp;MW of power.<ref name="EPT"/> Power transmission losses over the 735&nbsp;kV grid range from 4.5 to 8%, varying due to temperature and operating situations.<ref>{{cite web|title=Radisson Substation|url=http://www.hydroquebec.com/visit/virtual_visit/poste_radisson.html|access-date=2008-01-21|publisher=Hydro-Québec|archive-url = https://web.archive.org/web/20071221211828/http://www.hydroquebec.com/visit/virtual_visit/poste_radisson.html |archive-date = December 21, 2007}}</ref> The ''[[Ordre des ingénieurs du Québec]]'' named the 735&nbsp;kV power line system as the technological innovation of the 20th century for Quebec.<ref name="HQFr">{{cite web|url=http://www.hydroquebec.com/4d_includes/surveiller/PcFR2005-228.htm|title=Hydro-Québec célèbre le 40e anniversaire de la mise en service de la première ligne à 735&nbsp;kV|date=2005-11-29|publisher=Hydro-Québec|language=fr|access-date=2008-01-20}}</ref>

In the wake of the 1998 ice storm the [[Levis De-Icer]] was installed and began testing in 2007 and 2008.

{{wide image|Poste de distribution de Lévis panorama 2011.jpg|1000px|align-cap=center|The Lévis substation.}}

====Routes====
[[File:HQ - pylônes à chaînette.jpg|thumb|right|Cross rope "Chainette" ("little necklace") suspension pylons used on some parts of 735 kV lines between the James Bay hydroelectric complex and Montreal.]]
Hydro-Québec TransÉnergie's 735&nbsp;kV system consists of a set of six lines running from James Bay to Montreal and a set of four lines from Churchill Falls and the Manic-Outardes power stations to Quebec City. The [[South Shore (Montreal)|South Shore]] region of Montreal and the [[Saint Lawrence River]] between Montreal and Quebec City contain 735&nbsp;kV power line loops or rings.<ref name="HQMAP">{{cite web|title=Map of the Transmission System|url=http://www.hydroquebec.com/transenergie/en/pdf/carte_reseau.pdf|publisher=Hydro-Québec|access-date=2008-01-11}}</ref><ref name="GEImage">[[Google Earth]] images.</ref>

;James Bay
The James Bay hydroelectric dam complex contains several relatively short 735&nbsp;kV power lines that send electricity to three principal substations, ordered from west to east: [[Radisson Substation|Radisson]], Chissibi, and Lemoyne.<ref>{{cite web|title=James Bay |url=http://www.purplelizard.com/james%20bay.htm |publisher=Purple Lizard Maps |access-date=2008-01-11 |archive-url=https://web.archive.org/web/20080107093055/http://www.purplelizard.com/james%20bay.htm |archive-date=2008-01-07 |url-status=dead }}</ref> From these substations, six 735&nbsp;kV power lines<ref name="IEEEConnect"/> traverse the vast expanses of [[taiga]] and [[boreal forest]] in [[clear-cut]] stretches of land; this shows up clearly in aerial photos.<ref name="James Bay 4">{{cite web|title=James Bay 4 |url=http://www.purplelizard.com/james%20bay4.htm |publisher=Purple Lizard Maps |access-date=2008-01-11 |archive-url=https://web.archive.org/web/20080107074137/http://www.purplelizard.com/james%20bay4.htm |archive-date=2008-01-07 |url-status=dead }}</ref><ref>{{cite web|title=Vegetation Control: Overview |url=http://www.hydroquebec.com/vegetation/en/maitriser/en_bref.html |publisher=Hydro-Québec |access-date=2008-01-11 |archive-url=https://web.archive.org/web/20071228085539/http://www.hydroquebec.com/vegetation/en/maitriser/en_bref.html |archive-date=2007-12-28 |url-status=dead }}</ref> The terrain that the power lines cross is for the most part not mountainous, but smooth and replete with lakes.<ref name="GEImage"/> Generally, four of the lines runs together in two pairs and the other two run solo, although the two single lines sometimes do run in a pair.<ref name="MAP2"/> Two intermediate 735&nbsp;kV power lines, one in the north and one in the south, connect all six power lines along their path to southern Quebec.

As the lines continue south, they diverge into two sets of three 735&nbsp;kV transmission lines. The eastern set heads to Quebec City, where it connects with power lines from Churchill Falls and the 735&nbsp;kV power line loops in the Saint Lawrence River region. The western set heads to Montreal, where it too forms a ring of 735&nbsp;kV power lines around the city, linking to other power loops in the region.<ref name="HQMAP"/><ref name="GEImage"/> This section of Hydro-Québec TransÉnergie's power grid contains {{convert|7400|km|mi|-2|abbr=on}} of 735&nbsp;kV AC and 450&nbsp;kV DC power line.<ref name="SEBJ"/>

;Manic-Outardes power stations / Churchill Falls
[[File:Poste Micoua.jpg|right|thumb|The Micoua substation, on Quebec's [[Côte-Nord|North Shore]]. The substation is one of TransÉnergie's transmission hubs.]]
<!-- [[File:Churchill river newfoundland and churchill falls.PNG|thumb|200px|The location of Churchill Falls in Newfoundland and Labrador]] -->
Electrical power generated from the Churchill Falls power station is sent to Montreal and the population centres of the Northeastern United States, more than {{convert|1200|km|mi|-2}} away.<ref>{{cite web|title=Churchill Falls – Power from the Project|access-date=2008-01-11 |publisher=A Scoff an' Scuff's |url=http://www.ascoffanscuff.com/lab/cf/cf06.html |url-status=dead |archive-url=https://web.archive.org/web/20071030010530/http://www.ascoffanscuff.com/lab/cf/cf06.html |archive-date=2007-10-30 }}</ref> Starting from the generation station in [[Newfoundland and Labrador]], the power lines span a distance of {{convert|1800|m|ft|-3}} over the [[Churchill River (Atlantic)|Churchill River]] [[Canyon|gorge]] and run generally south-southwest for {{convert|203|km|mi|0}} as three side-by-side power lines in a cleared right-of-way with a width of {{convert|216|m|ft|abbr=off}}.<ref name="CFH">{{cite web|title=The History of Churchill Falls: A Brief History|url=http://www.ewh.ieee.org/reg/7/millennium/churchill/cf_history.html|access-date=2008-01-11| publisher=Churchill Falls (Labrador) Corpororation and Institute of Electrical and Electronics Engineers|first=Peter|last=Green}}</ref> As they head southwest through [[boreal forest]], the lines generally traverse flat, smooth rolling hills.<ref name="IEEE700kV"/>

After the lines cross the Quebec-Labrador border, also known as the Hydro-Québec point of delivery,<ref name="CFH"/> the direction of the lines becomes due south, and they head to the [[Poste Montagnais, Quebec|Montagnais Substation]], a substation accessible only by [[Poste Montagnais Airport|an airport adjacent to it]]. A lone 735&nbsp;kV line stems off from the substation, heading to an [[open pit mine]] {{convert|142|km|mi|0}} the northwest. The terrain crossed by the power lines becomes hilly and mountainous south of the border. The lines reach over {{convert|800|m|ft|-2}} in elevation before descending.<ref name="GEEL">Google Earth elevations.</ref> The three lines continue heading south until they reach a substation on the North Shore of the [[Gulf of Saint Lawrence]]. From there on, the three lines parallel the North Shore as the Gulf narrows to the southwest toward the Saint Lawrence River discharge mouth. The northernmost power line then diverges from the other two to connect with Manic-Outardes power stations located on and around the Rivière aux Outardes and the Manicouagan River.

[[File:Hydro Quebec Boischatel Crossing.JPG|thumb|right|Triple 735kV Mae West towers at [[Boischatel, Quebec|Boischatel]] / [[L'Ange-Gardien, Capitale-Nationale, Quebec|L'Ange-Gardien]] limits, on [[Quebec Route 138|Route 138]] east of Quebec City, as lines crosses the St. Lawrence River south towards the [[Île d'Orléans]].]]
As the lines near Quebec City, the northern power line rejoins the other two 735&nbsp;kV power lines. The three lines, paralleled by another 735&nbsp;kV power line some distance to the north, span over the Saint Lawrence River to the South Shore region, where the lines form loops encompassing part of the Saint Lawrence River and the south shore. The loops are also connected to the ring of 735&nbsp;kV power lines around Montreal and power lines running south from James Bay.<ref name="HQMAP"/><ref name="GEImage"/>

===Electricity pylons===
Quebec's transmission system contains a variety of electrical pylons depending on era and voltage level. Older pylon designs tend to consume more material than the newer pylons and the higher the voltage level, the larger the tower.<ref name="Tower"/>

;735&nbsp;kV pylons
[[File:St jean htpl.jpg|thumb|300px|Two types of single-circuit 735 kV delta pylons near [[Saint-Jean-sur-Richelieu]] paralleled by a dual-circuit 315 kV line. The center 735 kV line uses a larger version delta pylon while the one to the right uses smaller one.]]

Hydro-Québec TransÉnergie uses several different types of electricity pylons to support their 735&nbsp;kV power lines.<ref name="HQJamesBay"/> All of them are single-circuit, meaning that each pylon carries one power line with three bundles of four electrical subconductors separated by spacers,<ref name="IEEE700kV"/> with each bundle transmitting [[Three-phase electric power|one phase]] of [[electric current|current]].

[[File:Pylônes près de Chapais04.JPG|left|upright=0.7|thumb|A series of V-guyed towers, near [[Chapais, Quebec]].]]
The earliest type of tower used was a massive self-supporting [[delta pylon]], or waist pylon,<ref name="Tower">{{cite web|title=Types of Towers|url=http://www.hydroquebec.com/learning/transport/types_pylones/index.html|publisher=Hydro-Québec|access-date=2008-01-20 |archive-url = https://web.archive.org/web/20080113140131/http://www.hydroquebec.com/learning/transport/types_pylones/index.html |archive-date = January 13, 2008}}</ref> which consumed 21 [[tonne]]s of [[steel]] per kilometre of line.<ref name="HQJamesBay"/> This type of pylon was used for the first 735&nbsp;kV power line from the Manic-Outardes power stations to the load centre of Montreal.<ref name="GEImage"/> There are two significant variations of the delta pylon; one has longer side crossbars such that all three bundles of conductors are suspended on V-shaped [[Electrical insulator#Telegraph and power transmission insulators|insulators]].<ref name="TTW">{{cite web|title=Transmission Towers in Winter |url=http://pro.corbis.com/popup/Enlargement.aspx?mediauids=%7Bced9594f-da50-4722-a7d3-c1d7c6359960%7D%7C%7Bffffffff-ffff-ffff-ffff-ffffffffffff%7D&qsPageNo=1&fdid=&Area=Search&TotalCount=34&CurrentPos=9&WinID=%7Bced9594f-da50-4722-a7d3-c1d7c6359960%7D |archive-url=https://archive.today/20140409014019/http://pro.corbis.com/popup/Enlargement.aspx?mediauids=%7Bced9594f-da50-4722-a7d3-c1d7c6359960%7D%7C%7Bffffffff-ffff-ffff-ffff-ffffffffffff%7D&qsPageNo=1&fdid=&Area=Search&TotalCount=34&CurrentPos=9&WinID=%7Bced9594f-da50-4722-a7d3-c1d7c6359960%7D |url-status=dead |archive-date=2014-04-09 |publisher=[[Branded Entertainment Network|Corbis.com]] |access-date=2008-01-11 |first=Perry |last=Mastrovito |year=2001 }}</ref> The other has shorter side crossbars, such that the two outside bundles are hung on a vertical insulator string and only the middle bundle is hung with a V-shaped insulator.<ref>{{cite web|title=Transmission Towers for Hydroelectric Power Lines |url=http://pro.corbis.com/popup/Enlargement.aspx?mediauids=%7Bb0956297-ea50-4ea2-8a59-707781fe372f%7D%7C%7Bffffffff-ffff-ffff-ffff-ffffffffffff%7D&qsPageNo=1&fdid=&Area=Search&TotalCount=34&CurrentPos=25&WinID=%7Bb0956297-ea50-4ea2-8a59-707781fe372f%7D |archive-url=https://archive.today/20140409013957/http://pro.corbis.com/popup/Enlargement.aspx?mediauids=%7Bb0956297-ea50-4ea2-8a59-707781fe372f%7D%7C%7Bffffffff-ffff-ffff-ffff-ffffffffffff%7D&qsPageNo=1&fdid=&Area=Search&TotalCount=34&CurrentPos=25&WinID=%7Bb0956297-ea50-4ea2-8a59-707781fe372f%7D |url-status=dead |archive-date=2014-04-09 |publisher=Corbis.com |access-date=2008-01-11 |first=Roger |last=Ressmeyer |date=1990-10-29 }}</ref>

Over the years, Hydro-Québec researchers engineered a new type of pylon, the V-[[guyed]] tower, which reduced materials consumption to 11.8 tonnes of steel per kilometre of power line.<ref name="HQJamesBay"/> This type of tower also includes a variation with longer side crossbars, where all conductors are hung with a V-shaped insulator<ref>{{cite web|title=Transmission Lines|url=http://www.ourlabrador.ca/viewphoto.php?id=118|publisher=Our Labrador|access-date=2008-01-11}}</ref> and one with shorter side crossbar, where only the middle bundle hangs from the insulator and the side bundles are strung on vertical insulator strings.<ref>{{cite web|title=Day 3: Radisson & Chisasibi |url=http://www.purplelizard.com/james%20bay2.htm |publisher=Purple Lizard Maps |access-date=2008-01-19 |archive-url=https://web.archive.org/web/20080107074124/http://www.purplelizard.com/james%20bay2.htm |archive-date=2008-01-07 |url-status=dead }}</ref><ref>{{cite web|title=Houses Covered in Snow |url=http://pro.corbis.com/popup/Enlargement.aspx?mediauids=%7B1378524a-05e8-4a3b-8328-ff7887d2b77a%7D%7C%7Bffffffff-ffff-ffff-ffff-ffffffffffff%7D&qsPageNo=1&fdid=&Area=Search&TotalCount=34&CurrentPos=20&WinID=%7B1378524a-05e8-4a3b-8328-ff7887d2b77a%7D |archive-url=https://archive.today/20140409013937/http://pro.corbis.com/popup/Enlargement.aspx?mediauids=%7B1378524a-05e8-4a3b-8328-ff7887d2b77a%7D%7C%7Bffffffff-ffff-ffff-ffff-ffffffffffff%7D&qsPageNo=1&fdid=&Area=Search&TotalCount=34&CurrentPos=20&WinID=%7B1378524a-05e8-4a3b-8328-ff7887d2b77a%7D |url-status=dead |archive-date=2014-04-09 |publisher=Corbis.com |access-date=2008-01-11 |first=Perry |last=Mastrovito |year=2001 }}</ref>

During the construction of the James Bay transmission system, the cross-rope suspension tower was invented.<ref name="HQJamesBay"/> This type of tower features two guyed-tower legs similar to the V-guyed tower, but the two legs don't converge at the tower base. In the case of the cross-rope suspension tower, the tower legs are spread apart on two different foundations.<ref name="James Bay 4"/> In addition, the crossbar is replaced by a series of suspension cables with three vertical insulator strings to support the three bundles, which allows this design to consume only 6.3 tonnes of steel per kilometre of line.<ref name="HQJamesBay"/> The design is also known as the Chainette (little necklace).<ref>{{cite web|title=Unique Suspension System Conquers Rugged Terrain|url=http://tdworld.com/mag/power_unique_suspension_system/|publisher=Transmission&Distribution World|date=1997-08-01|first=H. Brian|last=White|access-date=2008-01-11}}</ref>

TransÉnergie uses [[two-level pylon]]s for angle towers or structures on 735&nbsp;kV power lines to change the direction of the line or switch the position of the conductor bundles.<ref name="GEImage"/><ref name="TTW"/> Delta pylons and three-leg guyed towers are also used as angle towers; they are referred to as "penguins" by Hydro-Québec [[lineman (technician)|linemen]].<ref name="James Bay 4"/><ref>{{cite web|title=Transmission Tower |url=http://pro.corbis.com/popup/Enlargement.aspx?mediauids=%7Ba7d01d32-bb18-4c43-8982-42ba3bb04099%7D%7C%7Bffffffff-ffff-ffff-ffff-ffffffffffff%7D&qsPageNo=1&fdid=&Area=Search&TotalCount=34&CurrentPos=32&WinID=%7Ba7d01d32-bb18-4c43-8982-42ba3bb04099%7D |archive-url=https://archive.today/20140409013930/http://pro.corbis.com/popup/Enlargement.aspx?mediauids=%7Ba7d01d32-bb18-4c43-8982-42ba3bb04099%7D%7C%7Bffffffff-ffff-ffff-ffff-ffffffffffff%7D&qsPageNo=1&fdid=&Area=Search&TotalCount=34&CurrentPos=32&WinID=%7Ba7d01d32-bb18-4c43-8982-42ba3bb04099%7D |url-status=dead |archive-date=2014-04-09 |publisher=Corbis.com |access-date=2008-01-12 |first=Perry |last=Mastrovito }}</ref>

;Pylons for other voltage levels
Hydro-Québec TransÉnergie uses a combination of double-circuit [[three-level pylon]]s and single-circuit delta pylons to suspend electrical conductors of other voltages, such as 315&nbsp;kV.<ref name="GEImage"/><ref name="Tower"/><ref>{{cite web|title=Central Labrador:Virtual Tour Quebec Hwy 389 – Baie Comeau to Labrador City|url=http://tlhwy.com/central/virtualtour/hwy389/hwy38901.html|access-date=2008-01-11}}</ref> The ±450&nbsp;kV high-voltage direct current line in Hydro-Québec's power grid uses a T-shaped tower, lattice or pole, to support two bundles of three conductors on each side. The direct current power line sometimes uses two poles or a wider, pyramidal, self-supporting lattice structure for angle towers.<ref name="GEImage"/><ref>{{cite web|title=Photography featuring beautiful bridges, scenic highways and railroads. |url=http://massroads.com/gallery.php?go=go&word=450kv |publisher=Massroads.com |access-date=2008-01-12 |url-status=dead |archive-url=https://web.archive.org/web/20110610185717/http://massroads.com/gallery.php?go=go&word=450kv |archive-date=2011-06-10 }}</ref>

[[File:Centrale thermique de Tracy (2).jpg|thumb|left|175px|174.6 metre (572'10") pylon adjacent to Hydro-Québec's now-decommissioned [[Tracy Thermal Generating Station|Tracy power plant]].]]
;Other pylons
Hydro-Québec usually uses tall, large pylons to cross large bodies of water, like lakes and rivers. These towers are said to be prominent and the tallest pylon in Hydro-Québec's power grid is of this function. The tallest of these is located near the Tracy power station on the shore of the Saint Lawrence River, carrying a 735kV circuit between [[Lanoraie, Quebec|Lanoraie]] and [[Tracy, Quebec|Tracy]]. The pylon, the largest of its kind in Canada, is {{convert|174.6|m|ft|1}} tall, the same height as the [[Montreal Olympic Stadium]], and slightly larger than the [[Washington Monument]] in the United States ({{convert|555|ft|m|1}}).<ref name="Cross">{{cite web|title=Crossings|url=http://www.hydroquebec.com/learning/transport/types_pylones/index.html|publisher=Hydro-Québec|access-date=2008-02-15|archive-url = https://web.archive.org/web/20080113140131/http://www.hydroquebec.com/learning/transport/types_pylones/index.html |archive-date = January 13, 2008}}</ref>

;Pylon strength
The pylons and conductors are designed to handle {{convert|45|mm|in|abbr=off}} of ice accumulation without failure,<ref name="HB">{{cite journal|title=Glazed over: Canada copes with the ice storm of 1998|journal=Environment: Science and Policy for Sustainable Development|volume=41|pages=6–11|date=1999-01-01|author=Burton|doi=10.1080/00139159909604608}}</ref> since Hydro-Québec raised the standards in response to [[ice storm]]s in [[Ottawa]] in December 1986 and Montreal in February 1961, which left {{convert|30|to|40|mm|in|abbr=off}} of ice.<ref>{{cite encyclopedia |title=Ice Storm of 1998 |url=https://www.thecanadianencyclopedia.ca/en/article/ice-storm-1998 |first1=Laura Neilson |last1=Bonikowsky |first2=Niko |last2=Block |encyclopedia=The Canadian Encyclopedia |publisher=Historica Canada |date=11 February 2016}}</ref><ref name="Survive">{{cite encyclopedia |title=Surviving 1998's Great Ice Storm |first1=Brian |last1=Bergman |first2=Brenda |last2=Branswell |first3=Stephanie |last3=Nolen |first4=Dale |last4=Eisler |first5=John |last5=Geddes |url=https://www.thecanadianencyclopedia.ca/en/article/surviving-1998s-great-ice-storm |encyclopedia=The Canadian Encyclopedia |publisher=Historica Canada |date=13 June 2014}}</ref><ref name="Verglas">{{cite web|title=Verglas '98|url=http://www.haya.qc.ca/storm.htm|access-date=2008-01-12|date=1998-03-29|archive-date=2008-05-30|archive-url=https://web.archive.org/web/20080530003551/http://www.haya.qc.ca/storm.htm|url-status=dead}}</ref> This has led to the belief that Hydro-Québec TransÉnergie's electrical pylons are "indestructible".<ref name="Montreal1998">{{cite web|title=Montreal in the Ice Storm January 1998|url=http://home.thezone.net/~sharvey/icestorm.htm|access-date=2008-01-20|first=Stuart L.|last=Harvey|year=1998|archive-url=https://web.archive.org/web/20071112190513/http://home.thezone.net/~sharvey/icestorm.htm|archive-date=2007-11-12|url-status=dead}}</ref> Despite being more than three times higher than the Canadian standard of only {{convert|13|mm|in|abbr=off}} of ice tolerance,<ref>{{cite web|title=The cost of redundancy|url=http://www.energyrisk.com/public/showPage.html?page=7188|publisher=energyrisk|access-date=2008-01-12|archive-url=https://web.archive.org/web/20061110230336/http://www.energyrisk.com/public/showPage.html?page=7188|archive-date=2006-11-10|url-status=dead}}</ref> an [[North American ice storm of 1998|ice storm in the late-1990s]] deposited up to {{convert|70|mm|in|abbr=off}} of ice.<ref name="HB"/><ref name="Survive"/>

===Interconnections===
[[File:HQ - Poste Outaouais 4.jpg|thumb|upright=0.7|right|The Outaouais substation, the newest of 19 interconnections between Hydro-Québec's network and neighboring power grids.]]
Across North America, electricity transmission systems are interconnected into [[wide area synchronous grid]]s, or interconnections. Suppliers are legally required to follow reliability standards. In 2006, Quebec's transmission system was recognized by the [[North American Electric Reliability Corporation]] (NERC) as a full interconnection because it is asynchronous with neighboring systems. Quebec will consequently be able to develop its own reliability standards, as needed, and these will apply in addition to the relevant North American standards.<ref>{{Cite web|url=http://www.hydroquebec.com/transenergie/reliability/modele.html|title=TransÉnergie {{!}} Hydro-Québec|website=www.hydroquebec.com|access-date=2016-03-05|archive-url=https://web.archive.org/web/20110605110012/http://www.hydroquebec.com/transenergie/reliability/modele.html|archive-date=2011-06-05|url-status=dead}}</ref> Besides the [[Quebec Interconnection]], there are four other interconnections in North America: the [[Eastern Interconnection]], the [[Western Interconnection]], the [[Alaska Interconnection]] and the [[Electric Reliability Council of Texas]].

Hydro-Québec TransÉnergie has the following [[interconnector]]s with systems in neighboring provinces and states:<ref>{{Cite web|url=http://www.hydroquebec.com/transenergie/en/reseau-bref.html|title=TransÉnergie {{!}} Hydro-Québec|website=www.hydroquebec.com|access-date=2016-03-05}}</ref>
* New York: two connections. Capacity is 1,100 MW import, 1,999 MW export.
* Ontario: eight connections. 1,970 MW import, 2,705 MW export.
* New England: three connections. 2,170 MW import, 2,275 MW export.
* New Brunswick: three connections. 785 MW import, 1,029 MW export.
* Newfoundland and Labrador: one connection. 5,500 MW import, 0 MW export.
The maximum simultaneous delivery (export) for the interconnector common to New York and Ontario is 325 MW.

===High voltage direct current (HVDC) 450 kV===
{{Main|Quebec – New England Transmission}}
In addition to the six 735&nbsp;kV power lines that stem from the James Bay Project, a seventh power line was constructed as an {{convert|1100|km|mi}} northward extension of an existing [[high-voltage direct current]] (HVDC) line connecting Quebec and [[New England]]. This power line expansion was completed in 1990. As a result, the [[direct current]] power line is unique because there are multiple [[Static inverter plant|static converter and inverter station]]s along the {{convert|1480|km|mi|-1}} long power line.<ref name="IEEEConnect"/> It is also the first multiterminal HVDC line in the world. The ±450&nbsp;kV power line can transmit about 2,000&nbsp;MW of hydroelectric power to Montreal and the Northeastern United States.<ref name="ABB">{{cite web|title=The HVDC Transmission Quebec – New England|url=http://www.abb.com/cawp/gad02181/c1256d71001e0037c12568340029b5c4.aspx?&opendatabase&v=17ea&e=us&m=100a&|publisher=The ABB Group|access-date=2008-01-11|date=2007-02-08|archive-url = https://web.archive.org/web/20070311141612/http://www.abb.com/cawp/gad02181/c1256d71001e0037c12568340029b5c4.aspx?&opendatabase&v=17ea&e=us&m=100a& |archive-date = March 11, 2007}}</ref><ref>{{cite web|title=Contracts, All Requirements: Hydro-Québec Interconnection|url=http://www.mmwec.org/html/contracts.htm|publisher=Massachusetts Municipal Wholesale Electric Company|access-date=2008-01-12 |archive-url = https://web.archive.org/web/20071116063220/http://mmwec.org/html/contracts.htm |archive-date = November 16, 2007}}</ref><ref name="PED">{{cite book|title=Power Electronics Design: A Practitioner's Guide|last=Sueker|first=Keith H.|chapter-url=https://books.google.com/books?id=KuFt9Bcc9zYC&q=hydro+quebec+765+kv+transmission+mileage&pg=PA8|access-date=2008-01-20|publisher=Elsevier|isbn=978-0-7506-7927-5|pages=8–9|chapter=1|year=2005}}</ref>

====Route====
Beginning in the converter station next to the [[Radisson, Quebec|Radisson]] substation, the HVDC line heads south and roughly parallels the six 735&nbsp;kV power lines some distance to the west. It traverses the same type of terrain as the other six lines; the land is replete with lakes, wetlands, and forested rolling hills.<ref name="GEImage"/> Gradually, the power line turns to the southeast, as it crosses under several 735&nbsp;kV power lines.

After the six 735&nbsp;kV wires split up into two groups of three power lines each, the HVDC line follows the eastern group, and the western set diverges away.<ref name="MAP2"/><ref name="HQMAP"/> The line remains overhead until it reaches the north shore of the Saint Lawrence River near [[Deschambault-Grondines, Quebec|Grondines]], where the 450&nbsp;kV HVDC line descends into [[Saint Lawrence River HVDC Powerline Crossing|an underwater tunnel traversing the river]]. The power line surfaces on the south shore near [[Lotbinière, Quebec|Lotbinière]] substation. After the river crossing, the line enters into the Nicolet terminal near [[Sainte-Eulalie, Quebec|Sainte-Eulalie]], northeast of [[Drummondville]]. South of the terminal, the line heads south and after a relatively short distance, it enters the Des Cantons close to [[Sherbrooke]].

Leaving the Des Cantons station, the power line crosses the [[Canada–United States border|Canada–US border]] and passes through the hilly [[Appalachian Mountains]] in the [[U.S. state]] of [[Vermont]], reaching an elevation of about {{convert|650|m|ft|-1}}.<ref name="GEEL"/> The line then continues heading south-southeast and enters the state of [[New Hampshire]], where it reaches the Comerford terminal near [[Monroe, New Hampshire|Monroe]]. Continuing southward into [[Massachusetts]], the line reaches the Sandy Pond terminal outside of [[Boston]] in [[Ayer, Massachusetts|Ayer]].<ref name="PED"/> The terminal is the southernmost extent of the HVDC line.<ref name="GEImage"/><ref name="ABB"/>

In December 2008, [[Hydro-Québec]], along with American utilities [[Northeast Utilities]] and [[NSTAR (company)|NSTAR]], created a joint venture to build a new HVDC line from [[Windsor, Quebec]] to [[Deerfield, New Hampshire]].<ref>{{cite web|url=http://www.northernpass.us/route_information.html |author=Northern Pass Transmission |title=Route Information |publisher=Northern Pass Transmission LLC |year=2010 |access-date=2010-10-13 |url-status=dead |archive-url=https://web.archive.org/web/20101220225647/http://northernpass.us/route_information.html |archive-date=December 20, 2010 }}</ref> Hydro-Québec will own the segment within Quebec, while the segment within the US will be owned by ''Northern Pass Transmission LLC'', a partnership between Northeast Utilities (75%) and NSTAR (25%).<ref>{{cite news|date=2010-10-05 |first=Kyle |last=Alspach |title=NStar to build hydro power line |work=Boston Business Journal |url=http://boston.bizjournals.com/boston/stories/2010/10/04/daily23.html |access-date=2010-10-12}}</ref> Estimated to cost US$1.1 billion to build,<ref>{{cite news |first=John |last=Dillon |title=New Transmission Line Reaches Milestone |work=Vermont Public Radio |date=2010-10-08|url=http://www.vpr.net/news_detail/88975/ |access-date=2010-10-12 }}</ref> it is projected that the line will either run in existing right-of-way adjacent to the HVDC line that runs through New Hampshire, or it will connect to a right-of-way in northern New Hampshire that will run through the [[White Mountains (New Hampshire)|White Mountains]]. This {{convert|180|to|190|mi|adj=on}} line, projected to carry 1,200 megawatts, will bring electricity to approximately one million homes.<ref>{{cite news|url=http://www.rutlandherald.com/article/20081219/NEWS03/812190315/1004/NEWS03|title=Utilities plan for N.E. expansion|work=Rutland Herald|first=Louis|last=Porter|date=19 December 2008|access-date=2009-05-09|url-status=dead|archive-url=https://web.archive.org/web/20090615232130/http://www.rutlandherald.com/article/20081219/NEWS03/812190315/1004/NEWS03|archive-date=15 June 2009}}</ref>

===Other features===
TransÉnergie uses [[series compensation]] to alter the way electricity behaves in power transmission lines, which improves the electricity transmission efficiency. This reduces the need to construct new power lines and increases the amount of electric power sent to population centres. Series compensation is based on [[capacitor]] technology. To maintain its transmission system performance, TransÉnergie sets aside funds for research and application of new technologies.<ref name="Features">{{cite web|title=Discover Hydro-Québec TransÉnergie and its system: Features of Our Transmission System |url=http://www.hydroquebec.com/transenergie/en/reseau/caracteristiques.html |publisher=Hydro-Québec TransÉnergie |access-date=2008-01-10 |archive-url=https://web.archive.org/web/20071102155611/http://www.hydroquebec.com/transenergie/en/reseau/caracteristiques.html |archive-date=2007-11-02 |url-status=dead }}</ref> In addition to power transmission technology, Hydro-Québec plans to offer [[high-speed internet]] over its transmission lines within a few years;{{when|date=May 2020}} the utility started testing internet over its lines in January 2004.<ref>{{cite news|title=Hydro-Québec to test internet over power lines|url=http://www.cbc.ca/news/story/2003/11/21/power_lines031121.html|access-date=2008-01-12|publisher=[[CBC News]]|date=2003-11-24}}</ref>

==Major disruptions==
In spite of the transmission system's reputation and the fact Quebec escaped unscathed from the [[Northeast Blackout of 2003]], the system has experienced damage and service interruptions from severe storms in the past.<ref name="Features2"/><ref name="Features"/> Examples include the 1982 and 1988 Quebec blackouts prior to the large 1989 and 1998 power interruptions.

===1989 Geomagnetic storm===
{{Main|March 1989 geomagnetic storm}}
At 2:44 [[12-hour clock|am]] EST on March 13, 1989, a severe [[geomagnetic storm]], due to a [[coronal mass ejection]] from the [[Sun]], struck Earth.<ref name="Bnet"/><ref>{{cite news|title=Scientists probe northern lights from all angles|url=http://www.cbc.ca/health/story/2005/10/22/northern_lights_051022.html|publisher=[[CBC News]]|date=2005-10-22|access-date=2008-01-13}}</ref> Fluctuations within the [[magnetic field]] of the storm caused [[geomagnetically induced current]]s (GICs) to flow as direct current through Quebec's power lines, which are normally only conducting alternating current.<ref name="Bnet">{{cite magazine|title=Space weather|url=https://www.discovermagazine.com/the-sciences/space-weather|magazine=[[Discover (magazine)|Discover]]|access-date=2022-06-29|date=July 31, 1995|first=Eric J.|last=Lerner}}</ref> The insulating nature of the [[Canadian Shield]] igneous rock directed the GICs to the power lines. The conductors then forwarded this current to sensitive [[electrical transformer]]s, which require a certain voltage amplitude and frequency to function properly. Although most GICs are relatively feeble, the nature of those currents destabilized the voltage of the power grid and unbalanced current spikes erupted everywhere.<ref name="Bnet"/>

Accordingly, protective measures were taken in response. To save the transformers and other electrical equipment, the power grid was taken out of commission, as [[circuit breaker]]s tripped all over Quebec and shut off the power.<ref>Bolduc, 2002</ref> Within less than 90 seconds, this wave of breaking circuits left the entire transmission grid out of service. The collapsed power grid left six million people and the rest of Quebec [[power outage|without electricity]] for hours on a very cold night. Even though the blackout lasted around nine hours for most places, some locations were in the dark for days. This geomagnetic storm caused about C$10 million in damage to Hydro-Québec and tens of millions to the customers of the utility.<ref name="Bnet"/>

===1998 ice storm===
{{Main|North American ice storm of 1998}}
[[File:1998 Ice Storm map.png|thumb|300px|Map showing precipitation amounts for Quebec and the Northeastern United States]]
From January 4/5 to January 10, 1998, warm moist air from the south overriding cold air from the north produced an [[ice storm]], leading to over 80 hours of freezing rain and drizzle.<ref>{{cite web|title=A closer look at a rare situation: Weather Situation |url=http://www.msc-smc.ec.gc.ca/media/icestorm98/icestorm98_a_closer_look_e.cfm |access-date=2008-01-16 |publisher=[[Environment Canada]] |url-status=dead |archive-url=https://web.archive.org/web/20060626235616/http://www.msc-smc.ec.gc.ca/media/icestorm98/icestorm98_a_closer_look_e.cfm |archive-date=June 26, 2006 }}</ref><ref name="Worst?">{{cite web|title=The worse ice storm in Canadian history? |url=http://www.msc-smc.ec.gc.ca/media/icestorm98/icestorm98_the_worst_e.cfm |date=2002-12-18 |access-date=2008-01-16 |publisher=Environment Canada |url-status=dead |archive-url=https://web.archive.org/web/20060719084957/http://www.msc-smc.ec.gc.ca/media/icestorm98/icestorm98_the_worst_e.cfm |archive-date=July 19, 2006 }}</ref> For days, a continuous shower of mostly freezing rain amounted to {{convert|70|–|110|mm|in|abbr=off}} of water equivalent of precipitation.<ref name="McCready">{{cite web|title=Ice storm 1998: Lessons learned|url=http://www.treecanada.ca/cufc6/proceedings/papers/McCready.pdf |access-date=2008-01-12 |publisher=6th Canadian Urban Forest Conference |first=Jim |last=McCready |date=2004-10-23 |url-status=dead |archive-url=https://web.archive.org/web/20060818195417/http://www.treecanada.ca/cufc6/proceedings/papers/McCready.pdf |archive-date=2006-08-18 }}</ref> Places like Montreal and the South Shore were especially hard hit, with {{convert|100|mm|in|1|abbr=on}} of largely freezing rain falling.<ref name="Worst?"/> These heavy precipitation totals wreaked havoc on the regional power transmission system.

;Physical damage
Five to six days of freezing rain and precipitation crippled the Hydro-Québec power grid in the Montreal and South Shore regions. In an area {{convert|100|by|250|km|mi|abbr=off}}, some 116 transmission lines were out of commission, including several major 735&nbsp;kV power lines and the Quebec–New England HVDC ±450&nbsp;kV line.<ref name="DAWG">{{cite web|title=DAWG Database 1998: January 1, 1998–December 31, 1998|url=http://www.nerc.com/~dawg/database/dawg-98.html#top |access-date=2008-01-12 |publisher=North American Electric Reliability Corporation |archive-url=https://web.archive.org/web/20080108015339/http://www.nerc.com/~dawg/database/dawg-98.html#top |archive-date=2008-01-08 |url-status=dead }}</ref> 
[[File:Ice Storm 98 trees line Noaa6198.jpg|thumb|left|Damage to trees and a power distribution line]] 
Through successive waves of freezing precipitation, more than {{convert|75|mm|in|abbr=off}} of radial ice accumulated on the electrical conductors and the pylons themselves. This ice coating adds an additional weight of 15 to 20 kilograms per metre of conductor (10 to 20&nbsp;lb/ft). Even though the electrical wires can withstand this extra weight, when combined with the effects of wind and precipitation, these conductors may break and fall.<ref name="PowerDamage"/> The pylons, designed to withstand only {{convert|45|mm|in|abbr=off}} of ice accretion, buckled and collapsed into twisted heaps of mangled steel.<ref name="Verglas"/> Cascading failures occurred on several transmission lines, where the collapse of one or more towers left a row of fallen pylons.<ref name="DAWG"/><ref>{{cite journal|last=Tucker|first=Kyle|author2=Asim Haldar|date=2007-10-04|title=Numerical Model Validation and Sensitivity Study of a Transmission-Line Insulator Failure Using Full-Scale Test Data|journal=IEEE Transactions on Power Delivery|volume=22|issue=4|page=2439|doi=10.1109/TPWRD.2007.899781|s2cid=36367198}}</ref>

Of all the pylons damaged, some 150 were pylons supporting 735 kV lines,<ref name="HB"/> and 200 towers carrying 315 kV, 230 kV, or 120 kV power lines collapsed as well.{{Ref label|note01|B|a}}<ref name="DAWG"/> In a region bounded by [[Montreal]] between [[Saint-Hyacinthe, Quebec|Saint-Hyacinthe]], [[Saint-Jean-sur-Richelieu]] and [[Granby, Quebec|Granby]], dubbed the "triangle of darkness", half of the overhead power grid was out of service.<ref name="MURE">{{cite web|title=Failure of Public Utilities: Risk Management and Insurance: Pages 5–7 |url=http://www.munichre.com/publications/302-03810_en.pdf |year=2003 |access-date=2008-01-10 |publisher=[[Munich Re]] }}{{dead link|date=April 2017 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> Quebec ordered myriad conductors, crossarms, and wire connections to repair the ones disabled by the storm in the electrical transmission and [[electric power distribution]] system.<ref name="HB"/> In all of Quebec, 24,000 poles, 4,000 transformers, and 1,000 electrical pylons were damaged or destroyed,{{Ref label|note01|B|b}} more than {{convert|3000|km|mi|-3|abbr=on}} of downed electrical wires; this cost a total of C$800 million to repair.<ref name="McCready"/><ref name="PowerDamage">{{cite web|title=Ice Storm Damage: Powerlines|url=http://snrs.unl.edu/amet451/bartlett/icedamage.htm |access-date=2008-01-12 |url-status=dead |archive-url=https://web.archive.org/web/20071116172408/http://snrs.unl.edu/amet451/bartlett/icedamage.htm |archive-date=2007-11-16 }}</ref>

;Power outage
With over 100 transmission lines paralyzed by the ice, Quebec fell into a massive power outage in the cold Canadian winter. Even though power restoration initiated after the first blackouts, large numbers of Quebecers were in the dark.<ref name="DAWG"/> At the height of the blackout, some 1.4–1.5 million homes and customers, housing three<ref>Statistics Canada, The St. Lawrence River Valley 1998 Ice Storm: Maps and Facts (Ottawa, 1998); and [[Ontario Hydro]], The State of the Power Transmission Network, 1998.</ref> to more than four million people,<ref name="MURE"/> were in the dark.<ref name="Chill">{{cite web|title=Chilling memories of 1998 ice storm that battered Quebec, Ontario, Maritimes|url=http://www.macleans.ca/canada/wire/article.jsp?content=n010322A|publisher=[[The Canadian Press]]|access-date=2008-01-20|date=2008-01-03|first=Sidhartha|last=Banerjee|archive-url=https://web.archive.org/web/20110518174606/http://www.macleans.ca/canada/wire/article.jsp?content=n010322A|archive-date=2011-05-18|url-status=dead}}</ref><ref>{{cite web|title=Recollections of 1998's Great Ice Storm still bring shivers|url=https://nationalpost.com/news/canada/story.html?id=216041|publisher=[[National Post]] and CanWest News Service|access-date=2008-01-21|date=2008-01-04|first=Meagan|last=Fitzpatrick|url-status=dead|archive-url=https://archive.today/20080106181115/http://www.nationalpost.com/news/canada/story.html?id=216041|archive-date=2008-01-06}}</ref> Private companies and other utilities from other parts of Canada and the United States were sent in to help Hydro-Québec undertake this massive restoration task, but these efforts were complicated by the widespread damage of the power grid.<ref>[[Swiss Reinsurance Company]] Canada, Inside an Ice Storm (Toronto, 1998).</ref> Blackouts in some areas lasted for 33 days, and 90% of those affected by the blackout had no power for more than seven days.<ref name="HB"/><ref name="McCready"/> Although power was fully restored to all locations in Quebec by February 8, 1998, it wasn't until mid-March that the power facilities were back in service.<ref name="DAWG"/> By then, much social and economic damage had occurred, such as ruined food and deaths resulting from lack of electric heating.<ref name="HB"/>

After the power outage was over, Hydro-Québec made numerous upgrades to its system in order to improve the power grid. Examples include the strengthening of electrical pylons and power poles, and increasing the power supply. This was done to enable the utility to restore power more rapidly in the case of a massive ice striking Quebec again. Hydro-Québec has stated that it is better-prepared to handle an ice storm with the same magnitude as the one of 1998.<ref name="McCready"/>

=== 2004 hydro tower bombing ===
In 2004, shortly before [[U.S. President]] [[George W. Bush]]'s visit to Canada, a tower along the Quebec – New England Transmission HVDC circuit in the Eastern Townships near the [[Canada–United States border|Canada–US border]] was damaged by explosive charges detonated at its base. The [[Canadian Broadcasting Corporation|CBC]] reported that a message, purportedly from the [[Résistance internationaliste]] and issued to the ''[[La Presse (Canadian newspaper)|La Presse]]'' and ''[[Le Journal de Montréal]]'' newspapers and the [[CKAC]] [[radio station]], stated that the attack had been carried out to "denounce the 'pillaging' of Quebec's resources by the United States."<ref>Canadian Broadcasting Corporation [http://www.cbc.ca/montreal/story/qc-hydro20041206.html],''Group claims responsibility for hydro tower bomb'', 6 December 2004</ref><ref>[https://web.archive.org/web/20050929091625/http://www.greenanarchy.org/index.php?action=viewactiondetail&actionId=61 Earth Liberation: "Bomb Attack On a Hydro-Quebec Tower", December 6, 2004 (from Google cache).]</ref>

==Criticism==
{{See also|James Bay Cree hydroelectric conflict}}
The performance of Hydro-Québec TransÉnergie's power grid during the 1998&nbsp;ice storm raised questions about the fundamental concept, vulnerability, and reliability of the grid.<ref name="HB"/> Critics noted that the power generation facilities were located approximately {{convert|1000|km|mi|abbr=on|-2}} away from population centres and that there was a lack of local power stations around Montreal, which is served by only six 735&nbsp;kV feeder lines;<ref>Report on the State of the Power System, submitted to the ministre d'etat des ressources naturelles du Quebec, 21 January 1998.</ref> five of these lines form a loop called the "ring of power" around the city. When the ring failed on January 7, 1998, roughly 60% of Greater Montreal's power supply was offline.<ref name="MURE"/> Hydro-Québec's large above-ground transmission and distribution system was considered to be exposed to natural disasters, although the cost of undergrounding the grid was prohibitive.<ref name="HB"/>

The technology utilized on Hydro-Québec TransÉnergie grid also came under fire from critics. It is claimed that this technology, used to improve performance, safety, and reliability, made people in Quebec over-dependent on the power grid for their energy needs, since electricity, especially hydroelectric power, makes up over 40% of Quebec's energy supply.<ref name="MURE"/> This dependence, evidenced by the fact Ontario farmers had more backup generators than farmers in Quebec, can increase the severity of the consequences when the grid fails, as it did in January 1998.<ref name="HB"/>

==Notes==
:'''A.''' {{note label|note01|A|^}} Two figures are given for the length of the 735&nbsp;kV system: {{convert|11422|and|11527|km|mi|abbr=on|0}}.
:'''B.''' ^ {{note label|note01|B|a}}{{note label|note01|B|b}} Estimates on the total number of poles and pylons damaged / destroyed by the ice storm vary.

==References==
{{Portal|Renewable energy|Energy}}
;General
* {{Cite book|title=America's Electric Utilities: Past, Present and Future|edition=5|first=Leonard S.|last=Hyman|isbn=978-0-910325-25-7|year=1988|publisher=Public Utilities Reports}}
;Specific
{{Reflist}}

==External links==
{{Commons category|Hydro-Québec TransÉnergie}}
* [http://www.hydroquebec.com/transenergie/en/reseau-bref.html Transmission System Overview]
* [http://www.hydroquebec.com/learning/transport/types-pylones.html Types of pylons]
* [http://www.hydroquebec.com/transenergie/en/pdf/carte_reseau-2014.pdf Grid map 2014, 1.3 MB]. {{cite web |url= http://www.bape.gouv.qc.ca/sections/mandats/La%20Romaine_raccordement/documents/DA5.pdf |title= Map of electric transmission facilities in Quebec |access-date= 2010-08-14 |archive-url= https://web.archive.org/web/20120308102003/http://www.bape.gouv.qc.ca/sections/mandats/La%20Romaine_raccordement/documents/DA5.pdf |archive-date= 2012-03-08 |url-status= dead }}&nbsp;{{small|(16.0&nbsp;MB)}}
* [http://archives.cbc.ca/IDD-1-70-258/disasters_tragedies/ice_storm/ CBC TV archives of the 1998 Ice Storm]
* [https://web.archive.org/web/20110610185717/http://massroads.com/gallery.php?go=go&word=450kv Pictures of the Quebec–New England line in Massachusetts and New Hampshire]
* [https://web.archive.org/web/20081005220451/http://gazdemo.ygingras.net/wiki/Pylons Pictures of Quebec's pylons]

{{Good article}}

{{North American Electric Reliability Corporation}}

{{DEFAULTSORT:Hydro-Quebec's Electricity Transmission System}}
[[Category:Electric power transmission systems in Canada]]
[[Category:Hydro-Québec]]
[[Category:Electric grid interconnections in North America]]
[[Category:Energy in Quebec]]
[[Category:Electric power infrastructure in Canada]]
[[Category:Buildings and structures in Quebec]]
[[Category:Wide area synchronous grids]]