Topic:"System Reliability" in M12841

4.1 Adverse System Impacts The Generating Facility must not adversely affect the Distribution System or service to any other connected customers or facilities.

AI summary The Generating Facility is required to avoid causing adverse effects on the Distribution System or service quality for connected customers and facilities, ensuring operational integrity and reliability.

4.7 Off-Nominal Frequency Operation The transmission system in Nova Scotia is synchronously connected to the North American grid via three transmission ties to New Brunswick and the HVDC link to Newfoundland. As a result, frequency rarely...

AI summary Nova Scotia's transmission system is connected to the North American grid, resulting in minimal frequency variation. However, during periods of grid separation, frequency may fluctuate between 59.5 and 60.5 Hz. Compliance with multiple standards ensures proper generator settings for frequency tripping.

4.10 Thermal Limits and Overcurrent Protection Thermal limits of NSPI equipment shall not be exceeded as a result of the addition of the generating facility. Protection shall be provided to detect and cease energization for all phase-to-ph...

AI summary Section 4.10 mandates that NSPI equipment thermal limits must not be exceeded by new generating facilities. It requires fault detection and de-energization mechanisms for phase-to-phase and phase-to-ground faults on the NSPI Distribution System to ensure reliability and safety.

4.12 Automatic Start/Restart of Generation Facilities Individual generators are permitted to automatically start or restart after tripping from the Distribution System. This automatic restart may occur only after the Distribution System vo...

AI summary Generators may automatically restart after tripping from the distribution system only if voltages are restored, frequency stabilizes at 60 Hz, and a 5-minute delay has passed. This ensures system stability and safety during restart procedures.

4.14.1 Voltage Flicker The Interconnection Customer is to ensure that the operation of the Generating Facility does not cause voltage variations on the Distribution System that result in objectionable lamp flicker to other connected custom...

AI summary The Interconnection Customer must ensure the Generating Facility does not cause voltage variations leading to lamp flicker on NSPI's Distribution System. Limits for short-term (Pst ≤ 0.35) and long-term (Plt ≤ 0.25) flicker severity are defined per IEEE 1547-2018, measured at the POI. Compliance applies to all operational periods.

4.16 Voltage Regeneration Sustained voltage regeneration from the Interconnection Customer's Interconnection Facilities following the loss of a supply phase on the Distribution System is not permitted. Regenerated voltages may not be well...

AI summary Sustained voltage regeneration after a supply phase loss on the Distribution System is prohibited due to potential voltage instability and inadequate short-circuit protection. Interconnection Customers must assess their site's regeneration capability and design mitigations. Generator step-up transformers can regenerate voltage, but only some configurations maintain nominal levels, requiring interconnection protection to detect phase loss.

5.2 Short Circuit Limitations The design fault level of the 12.47 kV Distribution System is 9000 Amps, 194 MVA, although actual fault levels will vary from substation to substation and will decrease with distance from the substation. Short...

AI summary The 12.47 kV Distribution System has a design fault level of 9000 Amps (194 MVA), with actual levels varying by substation. Short circuits are managed via reclosers/circuit breakers that automatically reclose up to three times to restore service if faults persist.

5.6 Voltage Unbalance The voltage profile for distribution circuit between and the POI is shown in Figure 6 under peak load conditions with generators online. Figure 6: Voltage Profile at POI with Voltage Control Settings The average volta...

AI summary The voltage unbalance at the Point of Interconnection (POI) for solar generators connected to the 12.47 kV system averages 3.1%, exceeding acceptable limits. Rephasing loads downstream of the POI is proposed to resolve line-to-line voltage deviations. NSPI acknowledges typical voltage unbalance below 3% but cannot guarantee compliance under all conditions, placing responsibility on the Interconnection Customer.

5.7 Voltage Regulation and Voltage Dip As per section 6.17 of the DSIR, all inverter based Generating Facilities shall be CSA certified and meet the functional requirements of CSA C22.3 No. 9:20 "Interconnection of distributed energy resou...

AI summary The document discusses voltage regulation requirements for inverter-based generating facilities under DSIR, highlighting that the Brooklyn Solar farm's addition may cause voltage fluctuations exceeding allowable limits (2.5%) during peak load conditions, as shown by CYMDIST load flow analysis (3.86% change under heavy load).

6.4 Operational Control of Electrical Lines and Equipment NSPI shall have operational control over any Interconnection Facilities it deems necessary to ensure reliability or serviceability of the Distribution System. Operational Control of...

AI summary NSPI retains operational control over interconnection facilities to ensure distribution system reliability. Operational control of customer equipment is defined in the SSGIA, with the responsible party accountable for safe electrical line and equipment operation.

Commercial Information Items 1, 2, 3 and 4: Partial confidentiality was applied to costs associated with materials, contracts, freight, consulting, licensing and software details provided in the capital work orders. To protect value for cu...

AI summary NS Power argues that partial confidentiality for capital work order details (materials, contracts, software) is necessary to protect customer interests by preventing competitive disadvantage, ensuring fair pricing, and maintaining system security. Disclosure risks higher costs, reduced competition, and potential threats to grid reliability.