Transmittal of generator prepurchase specifications, March 1998

NYC 9/11 Public Portal Document

PPS-Generators

After a stabilization period, (user adjustable, 0-03 minutes), the shed load^ shall be automatically readied to the emergency is in discrete load increments until the until the bus has been loaded to 95% of it capacity.

k. The plant operator can manually override the predetermined loading sequence by turning the bus load optimizer selector switch to the "off" position. Individual "off-auto-on" selectors are provided for each discrete load. By operating these switches, the plant operator may remove and/or add individual loads as required. A light shall indicate when a load has been signaled to connect to the bus. A sums light will light when bus has been loaded to 95 % capacity and shall be labeled "Bus Loaded to Capacity." Should the plant operator inadvertently overload the bus between 110% and 115% the bus capacity, the unsupported load block (a block of load for which no generator is connected to the bus) shall be reshed.

If at any time the bus is overloaded greater than 115 % of the bus capacity or the bus frequency drops to 58 Hz or less for more than two seconds, then all bus optimizing loads as well as the lowest priority supported load block connected to the bus are shed. A status light annunciating a "Bus Overload" shall be activated examined by the plant operator. After taking appropriate actions, the condition may be reset via the "Bus Overload Reset" pushbutton.

I. Load Priority Selection

Each load shall be assigned a block shedding priority. The total user assigned load for each priority block shall not exceed the capacity of one engine generator set.

Each discrete load shall have a user assigned load re-add step #(1,2,3... .30). If a block of lad has been shed, the individual loads will be added back onto the bus in ascending order of the load step re-add# until the engine generator sets have reached 95 % of capacity.

Each discrete load shall also have a user entered maximum load DW value assigned to it. This value shall be used to determine if particular load can be re-added to the bus without exceeding the available bus capacity.

OEM PPS-34 Generators 7 WTC March 20, 1998

NYC-WTC_000166909