Stakeholders will have 15 days to comment on ISO-NE’s reorganized transmission planning guide, which will reduce the existing guide’s more than two dozen sections to four. It will be organized like a transmission needs assessment or solutions study report: Introduction; Modeling Assumptions; Reliability Criteria and Guidelines; and Analysis Methodology.

Lead engineer for system planning Steve Judd, who presented the new guide to the ISO-NE Planning Advisory Committee on Wednesday, said the need for the reorganization became apparent when staff found it difficult to identify the proper section for adding a new probabilistic methodology for creating base case dispatches.

Since the guide’s creation in 2013, Judd said, new information was added as additional sections at the end of the document. As a result, the current guide’s 26 sections are “in no cohesive order,” he said.

The new methodology (section 2.2.2 of the revised guide) aims to develop a “same-probability” curve to describe the combined likelihood of certain levels of load and generation unavailability.

Planners will use the curve to determine the representative amount of generation in megawatts to be modeled as out of service in the transmission needs assessment for the study area. Instead of modeling a particular number of generators out of service, the new concept models a representative quantity of generation as being unavailable.

Planners based the load level probability on the most recent capacity, energy, loads and transmission (CELT) forecast and 17 summer weeks of distribution curves.

The 15-day comment period will be triggered when the guide is posted, Judd said.

Stakeholders Seek Briefing on SOARES

Analysts conducting ISO-NE’s 2017 System Operational Analysis and Renewable Energy Integration Study (SOARES) will brief PAC stakeholders at a future meeting, Director of Regional Planning and Coordination Michael Henderson said.

Stakeholders requested the briefing by professor Amro M. Farid and his team at the Thayer School of Engineering at Dartmouth after Henderson reviewed the SOARES scope of work Wednesday.

ISO-NE spokeswoman Marcia Blomberg called SOARES “a key element” of Phase II of the 2016 New England Power Pool Scenario Analysis/Economic Study, which is focused on regulation, ramping and reserves. The study will address the reduction in traditional thermal generation that provide inertia and other reliability services.

No date has been set for the briefing. The SOARES project is expected to be completed by the end of the year.

Eversource Spending $22.7M to Replace 3 Transformers

Eversource Energy presented its plans to replace three aging transformers at a cost of a cost of about $22.7 million.

Eversource Director of Transmission System Solutions Bob Andrew said the three are among eight General Electric transformers aged 30 to 45 years in its system, half of which have shown significant deterioration. One, at Scobie Pond, N.H., was replaced after it failed in March following a short-lived refurbishment. Two new units will replace transformers at Littleton and Deerfield, N.H. In addition, a new spare transformer will be purchased to replace one that took the place of a fourth aging unit.

Cost allocation for the new transformers will be subject to review by the RTO’s Reliability Committee, Andrew said.

The four transformers’ internal insulation had deteriorated, resulting in the formation of methane and ethane in the transformers’ oil. Eversource will monitor the remaining four GE units for future trouble.

Andrew said the RTO has discussed the issue with GE. “The response was typical of the [original equipment manufacturer] with 30-year-old equipment: ‘Of course, you should buy one of our new transformers and replace it.’”

— Rich Heidorn Jr. and Michael Kuser