Milestone-Nomination:Eel River Back-to-Back High Voltage Direct Current Converter Station, 1972
Docket Number: 2009-07 Proposal Link: http://www.ieeeghn.org/wiki/index.php/Milestone-Proposal:Eel_River_Back-to-Back_High_Voltage_Direct_Current_Converter_Station,_1972
In the space below the line, please enter your proposed citation in English, with title and text. Text absolutely limited to 70 words; 60 is preferable for aesthetic reasons. NOTE: The IEEE History Committee shall have final determination on the wording of the citation
Eel River High Voltage Direct Current Converter Station, 1972
Operating since 1972, Eel River, New Brunswick is home to the world's first commercial solid state High Voltage Direct Current converter station. This 320 MW interconnection facility, built by Canadian General Electric and NB Power, incorporates high current silicon solid state thyristors to convert alternating current from Hydro Quebec to direct current and back to alternating, allowing asynchronous, stable power transfers to serve NB Power's customers.
The plaque may be viewed in the main lobby of the Eel River Dalhousie Generating Station, where it would be visible to employees and visitors for viewing. The original buildings are in existence, inside a High Voltage Transmission Terminal yard. The Eel River HVDC facility is a secured operational facility unavailable to the public. Dalhousie Generating Station, which is located nearby and has an office area and a large vestibule, accessible to the public.
In the space below the line, please describe the historic significance of this work: its importance to the evolution of electrical and computer engineering and science and its importance to regional/national/international development.
This converter station was historically significant because it was the first that was designed and built from solid state high voltage, high current thyristors. Previously the medium was a plasma in a glass envelope using mercury vapour. These had more losses and were prone to re-strikes during transient fault events. The mercury is considered a dangerous pollutant. Nelson River HVDC had used thyristors in a portion of the bridge to mitigate re-strikes but these were retrofits. The knowledge gained there served as a proving ground to give confidence for a full scale project at Eel River.
With this project, the march of solid state systems to higher current and voltage ratings was advanced another major step. In fact, the Eel River Station performance was such that the station ran at 10 % overload for the first 15 years without difficulty. The project allowed surplus Hydro Quebec energy to flow into New Brunswick which is synchronized with the Eastern Interconnection, without the risk of loss of transmission if disturbances happened in either New Brunswick or Hydro Quebec. Indeed Eel River served to govern and stabilize both systems with its External Control System, a benefit to either system in case of disturbances. This economically advantageous energy imported to the benefit of New Brunswick customers, allowed more expensive NB Power generation to be exported to New England where energy costs were higher, an economic advantage to the parties on both side of the US border.
What features or characteristics set this work apart from similar achievements?
As mentioned earlier, at Nelson River solid state devices were retrofitted to a portion of the converter bridges to prevent re-strikes and enhance transient performance of the station.
The electronic external control system enhancing governing and stability as a response to weighted system frequency and weighted system acceleration was a new feature which allowed both Hydro Quebec and NB Power to use the other system as a crutch during power system disturbances in either system. This feature has had a major beneficial impact on dynamic system performance. This is where a difference in frequency modulates the power transfer in a manner to assist the deficient system being governed back to safety. In the event of a difference in acceleration, the system slowing down is assisted by the other system while mitigating any power swings as quickly as possible to regain stability.
The triggering for the thyristors was achieved by using fibre optics to communicate the isolated trigger pulse to the thyristors at various voltage levels. This was an early application of another new technology, now ubiquitous.