Transmittal of generator prepurchase specifications, March 1998

NYC 9/11 Public Portal Document

PPS-Generators

The switchboard station battery shall be identical to the engine starting batteries as described herein. <

3) Control power distributed ftom within the system logic control umt shall require a discrete circuit isolated through a protective circuit breaker. Control power distribution circuit shall be defined, but not limited to a minimum of (30 circuits, each with its associated circuit breaker:

Generator and Total system PLC DC bus - DC to DC converter, etc.

Non PLC, System Logic Bus.

ATS/Customer Interface DC Bus for customer external connections (engine start signals, etc.)

d. Bus Underftequency Protection

The generator bus shall have a solid-state frequency monitor (Device 8IB) with integral time delay to initiateioad shedding upon a reduction of bus ftequency to 58 Hz or less for a period of two seconds or more. Upon sensing a bus underftequency, the system shall automatically shed the lowest priority load connected at the time of occurrence. This shed circuit shall override any manual load-add operation and shall lock out the manual load-add circuitry. It shall give visual and audible alarm annunciation of bus underftequency load shed.

e. Load Shed Bypass-Reset Pushbutton

Provide a pushbutton, load shed bypass-rest control switch. The switch shall provide for supervised operation over the load-shed, load-add circuits, controls shall be provided so that in the event a bus overload occurs resulting in a reduction in bus frequency, the lowest priority load will be shed automatically by an override circuit. One switch shall be provided for each priority block except first priority.

f. Main Bus Underfrequency Reset Pushbutton

Provide a bus underftequency reset pushbutton to rest bus underftequency load shed signal.

OEM PPS-32 Generators 7 WTC March 20, 1998

NYC-WTC_000166907