Transmittal of generator prepurchase specifications, March 1998

NYC 9/11 Public Portal Document

PPS-Generators

and load terminals and all auxiliary control contacts and circuitry only shall^ connected to permit automatic operations of the complete control system without actually connecting the generator to the main bus. In the disconnect position, main and auxiliary control contacts and circuitry shall be completely disconnected. The breaker drawout mechanism shall be mechanically interlocked with the breaker to permit drawout operation only when the breaker main contacts are open.

b. Generator Sensing Control

Control sensing panel shall be furnished to protect, monitor, and control the operation of each generator set.

Each generator sensing panel shall include the following components, devices, and indicators;

1) Reverse Power Proctective Relay (Device 32)

An adjusuble reverse power solid state relay shall be provided to detect a motorizing condition of the respective engine generator set. The trip setting shall be adjustable from 0 to 15 % of the forward power rating of the respective engine generator set. Response shall be independent of frequency over a range of 40 to 70 Hz. The relay shall include a test switch to enable the relay circuit to sense forward power for periodic testing and adjustment. The relay shall include a solid state linear time delay to insure compatibility with engine driven generator set characteristics. The time delay shall have a range of adjustability of 0.1 to 60 seconds and be factory set at 2.0 seconds. The relay shall respond to power, the inphase component of current, across a power factor range of 0.2 to unity, leading or lagging, with a repeatability within plus or minus 3.0%. Do not substitute relays with inverse time characteristics.

2) Generator Voltage Protective Relay (Device 27)

An undervoltage solid state relay shall be included to respond to the true r.m.s. value of the generator voltage. This relay shall have an adjustable pick up range of 75 % to 100% nominal and an adjustable dropout of 80% of pickup. Dropout shall have zero differential for time delay reset.

OEM PPS-37 Generators 7 WTC March 20, 1998

NYC-WTC_000166912