IEEE 765:2006 pdf free download

IEEE 765:2006 pdf free download.IEEE Standard for Preferred Power Supply (PPS) for Nuclear Power Generating Stations (NPGS).
3.1 acceptable: Demonstrated to be adequate by the safety analyses of the station.
3.2 alternate ac (AAC) source: An alternating current (ac) power source that is available to and located at or nearby a nuclear powcr generating station that mects the following requirements:
a) It may be connected to the PPS or the onsite emergency ac power system.
b) It has minimum potential for common-mode failure with PPS or ensue emergency ac power sources.
c) It is available in a timely manner after the onset of a station blackout.
d) It has sufficient capacity and reliability to operate all systems required for the following:
I) Coping with a station blackout
2) The time needed to bring the plant to and maintain it in a safe shutdown condition (non-design basis accident)
3.3 preferred power supply (PPS): The power supply from the transmission system to the Class IE distribution system that is preferred to furnish electric power under accident and post-accident conditions.
3.4 station blackout: The complete loss of alternating current (ac) electric power to the essential and nonessential switchgear buses in a nuclear power generating station (i.e., loss of the preferred power supply concurrent with turbine trip and unavailability of the onsite emergency ac power system). Station blackout does not include the loss of available ac power to buses fed by station batteries through inverters or by alternate ac sources.
4. General design criteria
4.1 General
The PPS shall consist of two or more circuits from the transmission system to the Class I E distribution system. Some examples of acceptable arrangements arc shown in Figure 2. Figure 3. and Figure 4.
4.2 Safety classification
The PPS is not a Class I E system. Thcrctbre. requirements that are associated with Class I E installations for redundancy, independence, separation. application of the singlc-fuilure criterion, seismic, and equipment qualification do not apply.
4.3 Function
The PPS provides electric power. as required. for the safe shutdown of the station and for the operation of safely systems. The PPS circuits may be used during all modes of operation to supply power to the Class lE and non-Class I E buses of the plant.