Topic:"System Reliability" in M03347

5.3 Province's Wind Integration Study The 2008, Hatch Ltd. Wind Integration Study identified and assessed the effects of integrating large scale wind power generation into Nova Scotia's electric power system. This study confirmed that "mor...

AI summary The 2008 Hatch Ltd. Wind Integration Study highlighted the need for detailed impact studies on transmission upgrades and operational demands from wind power integration. NSPI now monitors variable energy sources like wind to improve forecasting and ensure system stability and availability.

6.1 Operating Reserve Criteria As a member of the Maritimes Area of the Northeast Power Coordinating Council (NPCC), NSPI meets the operating reserve requirements as outlined in NPCC Document A-6, Operating Reserve Criteria . This criteria...

AI summary NSPI adheres to NPCC's operating reserve criteria, sharing ten-minute reserves with NBSO via a load-ratio share and maintaining 171 MW of ten-minute reserves. It anticipates increased regulating reserves due to wind generation and conducts biannual 18-month resource adequacy assessments. The Interconnection Agreement outlines shared reserve responsibilities.

6.2 Planning Reserve Criteria NSPI is required to comply with the NPCC reliability criteria. These criteria are outlined in NPCC Reliability Reference Directory #1 – Design and Operation of the Bulk Power System 5 and states that: The prob...

AI summary NSPI must meet NPCC reliability criteria by maintaining a 20% planning reserve margin and ensuring a loss of load expectation (LOLE) of no more than 0.1 day/year. The New Brunswick System Operator (NBSO) confirms this margin, along with 50 MW interconnection assistance, satisfies NPCC standards through annual and triennial reviews.

7.1 System Description The existing transmission system has over 5,200 kilometres of transmission lines at voltages at the 69 kV, 138 kV, 230 kV and 345 kV levels. - The 345 kV transmission system is approximately 468 kilometres in length...

AI summary The document details Nova Scotia's transmission system, including 5,200 km of lines at various voltage levels (69 kV to 345 kV), their construction materials, and interconnections with New Brunswick, Quebec, and Maine via the NPCC power system.

7.2 Transmission Design Criteria NSPI, consistent with good utility practice, utilizes a set of deterministic criteria for its interconnected transmission system that combines protection performance specifications with system dynamics and...

AI summary NSPI employs deterministic criteria for transmission system design, ensuring reliability through single contingency standards and Special Protection Systems (SPS). It adheres to NPCC guidelines for interconnected systems and leverages SPS within SCADA to manage stability and prevent overloads.

7.3 Transmission Life Extension NSPI has in place a comprehensive maintenance program on the transmission system aimed at maintaining reliability and extending the useful life of transmission plant. The program is centered on detailed tran...

AI summary NSPI has implemented a comprehensive maintenance program for its transmission system, focusing on inspections and prioritizing the replacement of components such as poles, crossarms, guywires, and hardware to maintain reliability and extend the useful life of the transmission plant.

The transmission plan presented in this document provides a summary of the planned reinforcement of the NSPI power system. The proposed investments are required to maintain system reliability and security and comply with System Design Crit...

AI summary This document outlines NSPI's transmission plan, which includes upgrades to maintain system reliability and comply with design criteria. Projects are subject to further studies and approval by the UARB. A Technical Planning Committee was established in 2008 to assess resource adequacy and transmission reliability, including inter-tie upgrades between Nova Scotia and New Brunswick.

7.5 NSPI/NB Interconnection Overview The power systems of Nova Scotia and New Brunswick are interconnected via three overhead transmission lines; one 345kV line from Onslow, Nova Scotia to Memramcook, New Brunswick, and two 138kV lines fro...

AI summary Nova Scotia and New Brunswick's power systems are interconnected via three transmission lines, with the 345kV line carrying 80% of total power. The interconnection ensures system reliability, with import/export limits set at 350MW export and 300MW import to manage single contingency losses. Flow on 138kV lines is influenced by regional loads.

Export Import Number of thermal units armed for NS system load level (Import less than generation rejection (maximum two) 22% of total system load) Reactive Power Support level in the Halifax Regional Municipality Percentage of dispatchabl...

AI summary The document discusses the potential risks to the NSPI system if it becomes separated from New Brunswick during export, leading to increased system frequency. To mitigate this, NSPI employs fast-acting Special Protection Systems to reject generation and stabilize the system.

1. 2010 - Work will begin on the construction of additional transmission to the Western Valley area. This will include the construction of a 138 kV circuit between Canaan Road and Tremont, a 138 kV termination at Canaan Road and the additi...

AI summary The 2010 document outlines transmission infrastructure upgrades, including new 138 kV circuits, transformer installations, and reliability improvements. Projects aim to prevent outages, replace aging equipment, and integrate renewable energy sources like wind farms. Key initiatives include insulator replacement, switchgear upgrades, and grid expansions to enhance system reliability and accommodate renewable generation.

SYSTEM DESIGN CRITERIA Nova Scotia Power's interconnected system is divided into several classifications, each of which is governed by different design criteria. These classifications are as follows: - 1. Primary Transmission - 2. Secondar...

AI summary Nova Scotia Power's system is categorized into five classifications (Primary Transmission, Secondary Transmission, etc.), each governed by specific design criteria combining protection performance, system dynamics, and steady-state requirements. Protection design assumes a single coincident protection element failure.

DEFINITIONS - 1. Primary Transmission is defined as the 345 kV transmission system interconnecting Lakeside-Onslow-Hopewell-Woodbine, and Salisbury, New Brunswick, the 230 kV transmission system interconnecting Brushy Hill-Onslow-Lingan-an...

AI summary The document defines key transmission system components and operational conditions, including Primary and Secondary Transmission systems, Electrically Remote Transmission, Sub transmission, and Interconnected Transmission System. It outlines Normal system conditions, encompassing load ranges, facility availability, generation dispatch, voltage stability, and thermal ratings.

I. PRIMARY TRANSMISSION SYSTEM Prime clearance times are defined to be 4.5 cycles first zone and 6 cycles second zone with permissive signal for both three-phase and line-to-ground faults. Back-up clearance times are defined to be 15 to 18...

AI summary The text defines prime and back-up clearance times for the primary transmission system, specifying 4.5 cycles (first zone) and 6 cycles (second zone) for prime clearance, with permissive signals for three-phase and line-to-ground faults. Back-up clearance times are set at 15–18 cycles for both fault types.

The Design Criteria7 are: - 1. From normal system conditions, the Interconnected Transmission System dynamic response shall be stable and positively-damped following a permanent three-phase fault on any one system element except a generato...

AI summary The design criteria outline stability requirements for the Interconnected Transmission System following faults, emphasizing positive damping, prevention of cascade tripping, adherence to thermal ratings, and voltage control within specified limits. Fault clearance timelines and system element protections are also specified.

II. SECONDARY TRANSMISSION SYSTEM Prime time clearance is defined to be 6 to 9 cycles for both three-phase and line-to-ground faults. (No additional expenditure may be made to reduce clearing times from 9 to 6 cycles without authorization...

AI summary The Secondary Transmission System defines clearance times for fault protection: prime time clearance (6-9 cycles), local back-up clearance (<30 cycles, preferably 20), and remote back-up clearance (<30 cycles with reduced coordination margins). Authorization from System Design is required to reduce prime time clearance below 9 cycles.

The Design Criteria are : - 1. From normal system conditions, the Interconnected Transmission System dynamic response shall be stable and positively-damped following a permanent three-phase fault on any one system element except a generato...

AI summary The Design Criteria outline requirements for the Interconnected Transmission System's stability and response to faults, including preventing cascade tripping, maintaining thermal ratings, voltage limits, and ensuring fault clearance. Criteria address three-phase and line-to-ground faults, steady-state conditions, and voltage regulation post-contingency.

III. ELECTRICALLY REMOTE TRANSMISSION Prime time clearance is defined to be 9 cycles for both three-phase and line-to-ground faults. Note 1 and Note 2.

AI summary Prime time clearance is defined as 9 cycles for both three-phase and line-to-ground faults, with additional context provided in Note 1 and Note 2. This technical specification relates to fault response parameters in electrically remote transmission systems.

NOTES: - 1. No expenditure may be made to reduce clearing times to reference values without authorization from System Design. - 2. Permissive tripping between an electrically remote bus and a transmission bus (or between 2 electrically rem...

AI summary The notes outline system design criteria for power operations, including expenditure authorization requirements for reducing clearing times, permissive tripping exemptions, and acceptance of designed load loss scenarios during remote system element failures. These rules emphasize operational flexibility and reliability.

The Design Criteria are: - 1. Sub transmission system loading shall be within the thermally limited ratings. - 2. The sub transmission system voltages shall not be less than 97.5 percent or greater than 105 percent of nominal. - 3. As far...

AI summary The design criteria outline technical standards for sub-transmission systems, including thermal limits, voltage ranges (97.5%-105% nominal), fault management, and contingency planning. It emphasizes voltage stability post-fault, backup solutions for transformer outages, and limitations on voltage changes during system disruptions.

Design Criteria - 1. Capacity for any individual transformation point shall, under nominal system conditions, be sufficient to meet the daily load requirements after due consideration is given to the following: - a) Economic dispatch or ou...

AI summary The design criteria outline requirements for system capacity and reinforcement to ensure reliability under normal and contingency conditions. Capacity must meet daily load demands considering economic dispatch and transformer loading, while reinforcement is mandated to prevent thermal damage or load unmet during single contingencies, factoring interconnections, generation, and transformer capacities.

NOTES : - 1. Reinforcement may be the economic choice even if (a), (b) and (c) or (d) result in satisfaction of the load supply criteria because estimated out-of-merit costs may significantly exceed the costs of capital advancement. - 2. T...

AI summary The notes discuss scenarios where reinforcement may be economically preferable despite meeting load supply criteria, potential need for additional transmission transformation due to system contingencies, and the possibility that criteria application may not result in new installations. Key considerations include out-of-merit costs, system reliability risks, and capital advancement trade-offs.

a) To facilitate a large import or export via NB interconnect To enable import, a new 345 kV transmission circuit would be required between Onslow to the New Brunswick system. An existing 230 kV circuit would be uprated to 345 kV to provid...

AI summary The text outlines infrastructure upgrades required to enable large imports or exports via the NB interconnect, including new 345 kV transmission circuits, uprating existing lines, reactive compensation, and a ring bus. Joint planning studies with New Brunswick are needed to assess system upgrades for firm import/export capacity.