National Grid proposes new 345-kV/115-kV station, six new transmission loops in New York

National Grid USA is seeking New York state regulatory approval to build and operate a new 345-kV/115-kV transmission station and six new transmission loops to connect three existing lines to that station in order to address low voltage conditions.

Niagara Mohawk Power d/b/a National Grid filed on July 30 its application with the state Public Service Commission (PSC) to amend the certificate of environmental compatibility and public need issued by the PSC in December 1975 to include the new project.  

“The project is one of the most critical of several planned reinforcements to address the present and long-range energy needs of the southwest region, which encompasses National Grid’s electric system in Chautauqua and Cattaraugus counties [in New York] and portions of Allegany and Erie counties,” National Grid said in its application.

Based on a 10-year study of the system, National Grid determined that low voltages exist for many different contingency conditions, that some of the low-voltage conditions could develop today and that the number and severity of low-voltage conditions would increase with any load growth in the area.

Voltages were found to be below the 90% low limit indicated in the company’s transmission planning criteria, which could result in damage to customer or utility-owned equipment.

National Grid also said that the project is needed to address voltages far below the acceptable levels indicated in the company’s planning criteria during contingency conditions, which have been further exacerbated by the closure of generation at NRG Energy‘s (NYSE:NRG) Dunkirk facility.

In November 1973, New York State Electric and Gas (NYSEG) and National Grid filed an application for the certificate authorizing the construction and operation of the New York state portion of a 345-kV electric transmission line from Homer City, Pa., to NYSEG’s Stolle Road substation in the town of Elma.

National Grid is now requesting that the PSC amend the certificate by authorizing the construction and operation of a new 345-kV/115-kV transmission station; two new 345-kV transmission loops, each about 250 feet long, to extend from the station to the National Grid-owned portion of the existing 345-kV Homer City-Stolle Road Line 37; and four new 115-kV loop connections, each about 650 feet long, to extend from the new station to two existing National Grid 115-kV transmission lines.

The station is proposed to be located on an 18.9-acre parcel located in the town of Humphrey in Cattaraugus County, near three existing transmission lines: the Homer City-Stolle Road Line 37; the Gardenville-Homer Hill Line 152; and the Arcade-Homer Hill Line 167, the company added.

The Homer City-Stolle Road Line 37 is a 200-mile, 345-kV line owned in part by NYSEG and National Grid and was placed into service in 1978. National Grid owns a 37.5-mile section.

National Grid’s 65.5-mile, 115-kV Gardenville-Homer Hill Line 152 was built in 1967, and subsequently split in 2009, resulting in the addition of the Arcade-Homer Hill Line 167, which is 32.7 miles long, the company added.

The project involves the rerouting of the Homer City-Stolle Road Line 37 into and out of the station by attaching to two 345-kV terminal structures. The two 115-kV lines, the Arcade-Homer Hill Line 167 and Gardenville-Homer Hill Line 152, will also be rerouted into the station, the company added. A total of six new transmission loops, two per line, will connect the existing transmission lines into the proposed station.

National Grid also said that the two transmission loops for the 345-kV line will be about 250 feet long and installed on two new 3-pole, 345-kV structures. The four transmission loops for the 115-kV lines will be installed on four new single-circuit structures and two individual double circuit structures.

The station, as proposed, will consist of a 345-kV section and a 115-kV section within a fenced-in area, about 4.4 acres, on a National Grid-owned parcel, the company said, adding that it compared three potential sites for the location of the station, considering various factors such as soils and number of residences.

The evaluation showed that the Five Mile Road site had advantages in scheduling, constructability, cost and accessibility.

Among other things, National Grid noted that the project is not expected to affect geologic features, minerals, cultural resources, wetlands or water quality.

National Grid is a subsidiary of National Grid plc. NYSEG is a subsidiary of Iberdrola USA, which is a subsidiary of Iberdrola S.A.

About Corina Rivera-Linares 3231 Articles
Corina Rivera-Linares, chief editor for TransmissionHub, has covered the U.S. power industry for the past 15 years. Before joining TransmissionHub, Corina covered renewable energy and environmental issues, as well as transmission, generation, regulation, legislation and ISO/RTO matters at SNL Financial. She has also covered such topics as health, politics, and education for weekly newspapers and national magazines. She can be reached at