ISO-NE will add five buses to the bulk power system list and remove seven others for various reasons, the Planning Advisory Committee learned on Thursday.

Dan Schwarting, lead engineer for transmission planning, presented the BPS list updates to the PAC and said reasons for the additions include planned transmission upgrades, changes to protection schemes, and a reduction in inertia in Nova Scotia and New Brunswick.

Two of the additional buses were previously identified as BPS in the proposed plan application (PPA) for the Southeast Massachusetts/Rhode Island (SEMA/RI) transmission upgrades, and all five were identified in the 2019 BPS assessment report.

Reasons for the seven bus removals include generation retirements, dynamic model changes and other system changes since 2016, Schwarting said.

Four buses were previously identified as new BPS in the PPA study but will not be added to the BPS list. All seven buses were identified in the 2019 BPS assessment report.

The Northeast Power Coordinating Council requires the identification of buses that are part of the BPS, with some NPCC criteria applying only to BPS buses or BPS elements, including Directory 1: Design and Operation of the BPS and Directory 4: System Protection Criteria.

BPS classifications are determined through a performance-based test, as described in NPCC Document A-10.

RSP Transmission Projects and Asset Conditions

New England saw cost increases of nearly $200 million on 11 transmission projects between June and October 2019, according to Brent Oberlin, the RTO’s director of transmission planning, who presented on Regional System Plan transmission projects and asset conditions.

Eight of the projects were in the Greater Boston area and had a combined cost increase of $157 million, which Eversource Energy attributed to “actual construction bids coming in higher than estimated costs, lengthy and extensive permitting, and restrictive permitting conditions,” Oberlin said.

The other three projects all were in the Seacoast New Hampshire Solution, in the Madbury-Portsmouth area, and experienced a combined cost increase of $40 million, which Eversource also attributed to actual construction bids coming in higher than estimated costs, lengthy and extensive permitting, and restrictive permitting conditions.

“This can’t keep happening; the estimates have to get more accurate,” said Dorothy Capra, director of regulatory services at the New England States Committee on Electricity. “You don’t want to keep upsetting state regulators.”

Eversource representatives at the meeting said they would be prepared to answer questions on the cost overruns in more detail at the PAC meeting in November.

There were no new projects since the June 2019 update, but three upgrades on the project list have been placed in-service, including two in Greater Boston and one in Greater Hartford and Central Connecticut, Oberlin said.

Eversource 1355 115-kV Line Rebuild

Eversource’s John Case presented the utility’s plans for an estimated $7.45 million line rebuild in Connecticut (+50% to -25%), with an estimated in-service date of May 2020.

Eversource proposes to rebuild the 115-kV 1355 transmission line from the Colony substation to Schwab Junction in Wallingford, Conn., replacing 14 aged and degraded structures with new steel structures.

The original 1927 steel lattice towers on the line have bent members, corrosion and tower legs located in standing water. The conductor and shield wire in this section are original to the line, thus 92 years old, and no longer standard Eversource transmission conductors, Case said.

The utility will reconfigure the circuit arrangement and right of way to reduce the structures and conductors required, eliminating seven structures and approximately three-quarters circuit-miles of conductor. The aged and degraded copperweld conductor and shield wires will be replaced with new standard conductors and optical ground wire.

Wood structures in this section date from 1966 and suffer from various degrees of woodpecker damage, rot, cracks and deteriorated steel mechanical connections.

Tx Owner Local System Plans

The PAC meeting was followed by a meeting of the Transmission Owner Planning Advisory Committee, a transmission owner-led forum. The TOs each provided brief introductions of their local system plans or those of their subsidiaries, including upcoming transmission projects within their areas.

Presenting plans were Avangrid, Emera Maine, Eversource, National Grid, New Hampshire Transmission and Vermont Electric Power Co.

– Michael Kuser