Transmission & System Operator

New Brunswick's Electricity Act (the "Act") was proclaimed on October 1, 2013. Among other things, the Act establishes the amalgamation of the New Brunswick System Operator (NBSO) with New Brunswick Power Corporation ("NB Power").

Legislation continues the requirement for open and non–discriminatory transmission access in New Brunswick. The system operation functions previously performed by the NBSO are now performed by Transmission and System Operator ("T&SO") within a vertically integrated NB Power.

NBSO's role in the adoption, monitoring and enforcement of North American reliability standards has been transferred to the New Brunswick Energy and Utilities Board.

What is the System Operator (SO) Portion of the Transmission & System Operator Division?

As one of only 15 Reliability Coordinators in North America, the SO oversees the reliable operation of the Maritimes Area (New Brunswick, Nova Scotia, Prince Edward Island and Northern Maine). The New Brunswick transmission grid is the hub of the Maritimes Area and is also strongly interconnected to New England and Québec.

The Reliability Coordinator is the entity that is the highest level of authority responsible for the operation of the Bulk Power System, and has the wide area view of neighbouring utilities. Reliability Coordinators have authority, operating tools, processes and procedures in place to prevent or mitigate emergency operating situations in order to maintain system reliability and keep the lights on.

The primary responsibility of the SO is to ensure a well-planned, safe, adequate and reliable Bulk Power System. This is accomplished by:

  • administering the NB Power Open Access Transmission Tariff and the Electricity Business Rules
  • undertaking long (ten-year), medium (seasonal) and short term (daily) planning to ensure reliability at least cost
  • coordinating outages
  • managing load and generation connections to the grid
  • controlling generation in real time to keep the system balanced and stable
  • overseeing interconnection agreements with our neighbours
  • liaising with other system operators and stakeholders on emerging issues

The SO works at the heart of the Maritimes power system,; coordinating all users of a power system, it directs the generator to balance the supply and demand of electricity, then directs its flow across the high voltage (345 kV, 230 kV, 138 kV, and 69 kV) transmission lines.

What does Reliability mean for the SO?

Reliability of supply, also called power system reliability, refers to two distinct but inherently related aspects: security and adequacy.


Security is the ability of the power system to respond in real time to random situations (contingencies) such as outages of power plants, unpredictability of consumption and wind generation, sudden disturbances on the transmission network, etc.


Adequacy is the ability of the power system to meet the aggregate power and energy requirements of the consumption at any time. Adequacy is dependent upon investments in peak load and base load plants to meet future load growth and to supply sufficient reserve margin in the long term.

The SO must ensure that the power system is in a secure operating state. The system must always be postured to ensure that it can handle a single contingency, meaning the loss of a generator, loss of transmission line, transformer, etc.

Why is Reliability so important?

On August 14, 2003, the Northeastern power grid had the largest blackout ever. The outage occurred quickly and rippled across a large area. Cities affected included New York, Cleveland, Ohio, Detroit, Michigan, and Toronto and Ottawa. Complete cities were shut down; creating massive chaos and leaving over 50 million people without power; approximately 70,000 MW of load was lost, and the cost to North America was in the billions of dollars.

In response to this blackout, the North American Electric Reliability Corporation (NERC) committed to take immediate actions to strengthen the reliability for the North American Bulk Power System. This led to changes in the NERC policies - reliability requirements increased and entities could no longer delegate their responsibilities. New Brunswick's new Electricity Act empowers the New Brunswick Energy and Utilities Board to adopt, monitor, and enforce NERC standards for which NB Power must implement and maintain compliance with.

How does the SO continue to maintain system reliability?

The primary responsibility of the SO is to maintain system reliability by controlling/monitoring various elements on the power system. The SO assures compliance with NERC reliability standards by controlling energy flows, maintaining required reserves, frequency and area control errors. Some of the SO's functions include:

Maintaining Sufficient Operating reserve: Reserve is extra MW capacity available to the system in the event that it is needed to maintain the balance between power generated and load consumed. Standards define how much reserve must be carried.

There must be enough reserve to cover the largest resource contingency, normally the Point Lepreau Nuclear Generating Station at 660 MW. For example, if Lepreau trips at 660 MW, 660 MW of generation must be available (activated locally or through reserve sharing agreements) within 15 minutes to correct interconnection flows with New England. If the SO does not provide that reserve power within 15 minutes, a NERC Standard is violated and penalties may require the SO to carry even more reserve to ensure this does not happen again.

Balancing and Frequency Control: The SO is responsible to balance the ongoing changes in system load demand using supply of generation to the grid.

The frequency of the Eastern Interconnection is typically 60 Hz. If the total generation being generated is equal to the customer demand, the frequency will remain at 60 Hz. If the generation exceeds load demand, frequency will increase. Conversely, if generation is less than the customer demand, frequency will decline. If a generator trips offline in New Brunswick, New Brunswick is considered to be under generating. Other NB generators will react to try to restore frequency through governor action, and secondary the Automatic Generation Controller (AGC) will increase the power output of selected generators within New Brunswick in response to the Eastern Interconnection system frequency, and or tie line loading.

System Control: The SO is responsible for maintaining all 69 kV, 138 kV, 230 kV, 345 kV voltage levels within limits to protect power system equipment and maintain reliable operation of the power system.

The SO has control of various power transformers, capacitor banks (increase voltage), and reactors (lower voltage) throughout the province to assist in maintaining voltage. If there is an event on the power system and the voltage needs adjustment, the operator will take action by sending a control signal to a device in the field to correct the issue. If necessary, the SO has the authority to re-dispatch generation, make curtailments, tap transformers, change power flows, curtail industrial customers, and shed customer load.

The SO is also responsible for ensuring no transmission lines/transformers become overloaded above their operating limit. If a transmission device is overloaded, the SO must take action within 5-15 minutes to alleviate this overload. The SO must also ensure the problem will not impact any other neighboring power systems. If neighbours are impacted, the SO has 30 minutes to alleviate this Interconnection Reliability Operating Limit (IROL).

Restoration: The SO has action plans ready for large-scale power system failure scenarios and the plans of contingency to rebuild the system after such events. Each year, the SO performs two emergency restoration training drills to ensure that there are sufficient and adequate plans in place to properly restore the power system in event of a blackout.

Maintenance: The SO is directly involved in the switching, maintenance planning and repair of the New Brunswick transmission system to ensure that reliability is maintained.

Reliability Analysis: The SO is continuously performing reliability studies to ensure we are operating in a reliable manner and to ensure we meet all the expectations defined by all the NPCC and NERC standards.