Research Project Summary Information
NYPH CHP Clip Implementation(ST10466-1)
New York Presbyterian Hospital
The NYPH is currently installing a 7.5 MW Solar gas turbine outfitted with a heat recovery steam generator (HRSG) to produce both electricity and steam for on-site use. The hospital is located in a critical load pocket and Consolidated Edison is not planning to upgrade the substation in this area until after 2014. Synchronous operation of the gas turbine is necessary in order for the hospital to maintain high reliability and avoid using its “dirtier” diesel generators for backup power. The facility is expected to commence the final installation/commissioning phase in the Spring 2008.
The Commutating Current Limiter (CCL) is integrated into the associated switchgear of its application. Typical cogeneration systems require switchgear (motor starters, protection, etc.); and the CCL device integrates well into this hardware, with no additional subsystems, keeping costs much lower. Upon initiation of the CHP portion of this project, Con Edison gave approval of the CLiP device to satisfy its concerns about fault current contributions to its grid from installed generators. The CLiP was also approved for use on a generator installation connected to an LIC network. With proper specifications, testing and installation carried through by the implementers, utilities will approve the generator connections and the associated fault current concerns with this CLiP device integrated. This project has the potential to alleviate the backlog of other synchronous parallel generation desires within constrained Con Edison territories.
The CCL device was tested for fault current sensing and firing logic prior to its installation in the motor control center of the synchronous generator, which it was protecting. Upgrading a Con Edison substation to support the intended project of installing 7.5 MW of power to the NYPH, would have resulted in costs between $380 - $1,000 per kW, depending on configuration of the substation vault and supporting equipment. The CCL CLiP device, installed within the NYPH facilities switchgear, allowed the customer to meet the synchronous parallel cogeneration requirements that can satisfy a fault current that might be caused by the cogeneration tripping off line. Compared to the $380 - $1,000 per kW cost of a substation upgrade, the CCL device was implemented at a cost of $29 per kW. The CCL provides a viable alternative to future customers of Con Edison and other utilities that desire their own synchronous parallel cogeneration systems.
The NYPH CHP project was able to proceed on schedule, startup, and operate in a synchronous parallel mode with the grid, using the Commutating Current Limiters (CCL) installed to satisfy the fault current mitigation requirement imposed by Con Ed within its constrained service territory. The project demonstrated that the CCL technology can be acceptable to the Con Ed utility as an alternative to substation upgrades for fault mitigation, and can additionally provide a cost effective method to implement and promote more synchronous parallel cogeneration installations on the Con Ed networks. The cost per kW of the CCL device equates to $29/installed kW, representing a very cost effective alternative to the typical approach of a utility sub-station upgrade of distribution switchgear. Shortly after installation and startup of the cogeneration system, Con Edison experienced a severe fault on their system, and the fault current introduced into the switchgear of the cogeneration unit, was high enough to trip a substation breaker and the CCL CLiP device. The CLiP responded appropriately, with all three phases of the supply triggering, and the fault discharging through the associated fuse. No equipment was impacted during this incident, and the CLiP isolated the fault in its intended manner. For the replacement cost ($30,000 total) of the three fuses affected, done by internal NYPH staff, the system was restored to original operating conditions.
New York Presbyterian Hospital
523 East 70th St., Annex 108
New York, NY 10021
Electric Power Delivery
NYSERDA Contact Information
R&D -Transport & Power Systems