Transmission & Distribution

A 138/13.8kV Class H substation with two substation transformers supplied by two overhead transmission lines O-1315 and W-2249.

Half the substation (the 138kV bay) shall be upgraded to 230kV.  Scope also includes the removal of all 138kV equipment and structures and the upgrading of the bay associated with Substation Transformer T1 to 230kV.

The new substation located on the Con-Ed Poletti site provides the interface point between the new Astoria II Power Plant and NYPA. A 345kV aerial transmission line feeds gas-insulated switchgear (GIS) arranged in a ring-bus configuration with four circuit breakers (with provisions to accept two additional feeders). The ring bus serves Con-Ed high pressure fluid filled feeders via overhead aerial cables and bus located in the adjacent switchyard. Two 150MVA shunt reactors were relocated from the decommissioned Poletti Generating Station and installed in the new switchyard.  In addition to installing all the GIS and switchyard power distribution equipment, E-J also installed all associated controls, instrumentation, and metering.

E-J’s scope also included a complete fit-out of all building services including lighting, power, mechanical, BMS, security, fire alarm and communications.  Due to environmental remediation of the soil, the project schedule was compressed to include peaking at 120 electricians with 2 shifts a day, 7 days a week.

This project is one of the largest transmission projects released by Pepco in 2013 and involved the work necessary to rebuild the existing Church – Townsend 138kV transmission line, Circuit 13833. The project consists of the replacement of the existing 138 kV transmission structures 1 through 15 and 230 through 308  between Townsend Substation (New Castle County, Delaware) and Church Substation (Queen Anne’s County, Maryland). The rebuilt line will be renumbered starting with structure 1 outside of Townsend Substation to structure 92 outside of Church Substation.  The new structures were offset from the existing transmission structures 65 ft. to minimize outage time. Structures 1 through 3 were rebuilt in-line as delta braced post structures. The remaining tangent structures were rebuilt as a single steel pole line with tangent structures having suspension insulators on steel davit arms. The existing structures along the existing line were removed after project completion. The line was rebuilt as a single circuit utilizing direct embedded weathering steel poles and self-supporting weathering steel poles on anchor bolt foundations.  The H-Frame structures were then removed and discarded per pre-set environmental guidelines.

Three (3) of the ninety-two (92) structures were single circuit tangent structures with 230 kV line braced post insulators in a delta configuration. Two (2) of the ninety-two (92) structures were single circuit 3-pole dead-end structures that utilized thru vangs to dead-end the conductor and OPGW shield wire. Eight (8) of the ninety-two (92) structures were single pole dead-end structures that utilized thru vangs to dead-end the conductor and OPGW shield wire (where specified). The dead-end structures were done using 230 kV suspension insulators. Seventy (70) of the ninety-two (92) structures were single circuit tangent structures with 230 kV suspension insulators on steel davit arms. Nine (9) of the ninety-two (92) structures were single circuit strain structures in a delta configuration on steel davit arms with 230 kV suspension insulators.  The conductor was 1590 45/7ACSR Lapwing.  The static wire was AFL fiber optical ground wire (OPGW) AC-85/638 0.638” diameter, specification DNO-7199.  The ADSS is 48 count fiber.

The work at the NYPA500 project included the erection, installation and testing of (2) 200MVA GSU, (1) 234MVA GSU and (2) auxiliary transformers, in addition to the installation and testing of (1) isolation transformer and (3) excitation transformers.

Dead end and PT structures along with associated 138kV switches were constructed to connect two of the three GSU transformers to the overhead transmission lines fed from the Astoria West substation. For design diversity, a pothead structure along with the associated switches was assembled to connect the third GSU to an underground 138kV feed which was also derived from the Astoria West ring bus.

The low side of these GSU transformers utilized a field welded 18kV Isophase bus to make the necessary connections to the combustion turbine and steam turbine generators as well as the auxiliary transformers. Power from the auxiliary transformers was delivered to the 4160V switchgear via a 5kV cable bus.

The Jamaica Bay Peaking Facility, located South of Jamaica Airport, serves the Long Island Power Autority grid as an additional energy source during high­ energy draw situations. Located on the same site, this plant runs in conjunction with the Bayswater Peaking facility constructed by E-J during the summer of 2002.

E-J also performed the installation of 15kV transmission yard equipment and interface to the Long Island Power Authority (LIPA) transmission lines. The design included bus duct from the station transformer into the transmission yard tower bus disconnect and the associated controls of the SCADA system.

The Grasslands Substation project called on E-J Electric to provide the complete “above grade” electrical package. The work within this scope included the rigging and placement of switchgear, a complete 3000A/4500A bus duct system, installation and termination of all control and power cables, placement and wiring of all control room equipment, (2) 500kVA station power transformers, complete fire alarm system, complete public address/paging system and completion of two 138kV/13.8kV transformer bays which included welding of cable bus, installation and adjustment of circuit switchers and circuit interrupters and all 125VDC control devices.

The station was completed on an aggressive schedule, made challenging by one of the areas most severe winters. This was the first time that Consolidated Edison Co. contracted this complete scope of work.

The project included 3,600 LF of 138kV transmission line from the Astoria Energy 500MW Power Plant to the Consolidated Edison Astoria East Substation.

The line consisted of 4 spans of double-circuit 1590 MCM ACSR overhead transmission line conductor on tubular steel towers and 1,700 LF of 12 – 2000 MCM solid die-electric cable (2 cables per phase) double-circuit encased 138kV underground transmission.

Both the overhead line and duct have provisions for a future circuit to be added.

A notable feature were the side by side 108′ tall transition towers where the overhead conductor was terminated and connected to the underground cable using 12 G&W oil-filled 138kV potheads.