NYPA Redirects Power Between 2 Lines by Using Transmission Control Device

Michael Saltzman

September 1, 2004


MARCY—An advanced feature of a new transmission-control device recently completed at the New York Power Authority’s (NYPA) Frederick R. Clark Energy Center here got its first use this week, with power redirected from one transmission line to another in the same substation.

NYPA utilized the new feature shortly before noon on Monday (Aug. 30) on instructions of the New York Independent System Operator (NYISO), which determined that system conditions warranted the transfer capability of the convertible static compensator (CSC), as the device is known, in addition to other actions.

“The utilization of equipment installed for the second and final phase of the convertible static compensator reflects New York State’s recognition under Governor George E. Pataki of the benefits of new technologies to improve the versatility and strength of its electric power system,” NYPA President and CEO Eugene W. Zeltmann said. “The new equipment allowed us to redirect power between two circuits at Marcy, responding to system conditions.”

The CSC operated in a mode referred to as static series synchronous compensator, or SSSC, one of several configurations the equipment is designed for.

Last June, Governor Pataki announced the completion of the second phase of the CSC, which was already providing significant benefits stemming from work finished in mid-2001.  Equipment installed under the project’s first phase provided voltage support for increasing power flow on the statewide power grid by up to 114,000 kilowatts (kw). The second phase increased the total amount to up to nearly 200,000 kw.

The NYISO, which oversees the operation of the state’s power grid, directed NYPA to activate the Phase 2 equipment to assist in maintaining reliable power flows.

The ISO issued the directive to make certain that a circuit between Roseton in Orange County and East Fishkill in Dutchess County would continue to operate within safe operating limits in the unlikely event of problems elsewhere on the system. The ISO asked NYPA to use the Phase 2 equipment to redirect a portion of the power on the circuit, which is part of the Power Authority’s Marcy-South transmission line, from Marcy to East Fishkill, and move it to another 345-kilovolt line extending to New Scotland in Albany County.

The new equipment operated for about two hours, before system conditions allowed the CSC to be returned to an operational mode for voltage support.

The Governor’s announcement in June of the equipment’s completion coincided with an event led by Lt. Governor Mary O. Donohue celebrating the milestone.

The $54 million CSC is largely contained in a gymnasium-sized building at the Clark Energy Center. The operations of NYPA’s 17 generating facilities and its 1,400 circuit-miles of transmission lines are monitored, and information is exchanged with the NYISO, from the Authority’s Energy Control Center at Clark.

NYPA invested more than $41 million in the transmission-control device, with the remainder provided by various power industry organizations with an interest in advancing the technology and sharing what’s learned from NYPA’s experience. They included EPRI (Electric Power Research Institute), the industry’s science and technology development organization; Siemens Power Transmission and Distribution, the manufacturer of the CSC; and more than 30 other utilities and independent system operators in the U.S., Canada and New Zealand.

The CSC belongs to a family of so-called FACTS technology—an acronym for Flexible Alternating Current Transmission Systems—in which high-speed, solid-state electronics are used rather than conventional electromechanical devices to control transmission voltage and power flow.