36C24618R0669-0003013.docx

VA McGuire

Appendix A

SEQUENCE OF OPERATION

Table of Contents

General

This system is comprised of (21) incoming main utility and emergency paralleling switchgear and (1) medium voltage chiller plant paralleling switchgear both controlled by the paralleling switchgear redundant Rx3i PLCs (one located in each lineup). The switchgears are:

1. GPS-1 – Incoming Main Utility & Emergency Paralleling Switchgear

2. GPS-2 – Chiller Plant Paralleling Switchgear

The GPS-1 Switchgear has (2) utility incoming sources (Utility 2 is future) and is segregated into (3) buses: Bus A includes the utility main and normal distribution, Bus B includes the emergency distribution and Bus C includes the generator paralleling source. GPS-1 switchgear also includes a ring bus connected via tie circuit breakers 52TA1 and 52TA2. The GPS-2 switchgear includes an incoming main circuit breaker, normally energized by the utility source but can be energized by the GPS-1 generators during extended outage mode. Both the GPS-1 and GPS-2 switchgears include both open and closed transition transfer operations with either Utility Source 1 or Utility Source 2.

GPS-1 System One-Line

Normal Breaker Status is as follows:

Controls

The system control is provided by redundant synchronized GE Rx3i PLCs. The primary PLC is provided in the Master Control Section located in switchgear GPS-1 and the secondary PLC is located in the GPS-2 (Chiller Plant) Switchgear. The system control is also equipped with redundant I/O.

NOTE: The existing PLC in the Chiller Plant Switchgear (GPS-2) will be re-programmed to provide redundancy with the new PLC and redundant I/O (in a standalone cabinet) will be added to the GPS-2 switchgear. Additionally, the existing Chiller Plant switchgear will be modified to allow momentary closed transition transfer (<100ms) in lieu of closed trasition sofltoad.

Each generator is provided with a dedicated PLC, GE Versamax, that controls the start/stop operation of the generator.

Master Control Section (GPS-1)

This section contains one the two redundant Master PLCs and a 24” Operator Interface Panel (OIP). It also contains the Master Control Stations (hard-wired). The OIT will provide visual information and control for both the GPS-1 and GPS-2 switchgear lineups.

Master Control Section (GPS-2)

This section contains one of the two redundant Master PLCs and will be re-programmed to provide redundancy with the new Master PLC located in GPS-1. The existing 24” OIT will be modified to match the new OIT in the GPS-1 switchgear, which will provide visual information and control for both the GPS-1 and GPS-2 switchgear lineups Control Power

125VDC 48VDC control power will be provided by a new 125VDC 48VDC Station Battery.

Control Switches Plant Selector Switch

One plant selector switch (PSS1) is mounted on the Master Control Section. This switch selects the connections for the Synchroscope and sync check relay and is used to verify synchronism prior to a manual (or manually initiated) paralleling operation.

Plant Selector Switch 1

Master Control Station

The master control station is located on the master control door.

Priority Load Shed Bypass/Reset (1 provided for each priority block)

Generator Controls

The Generator Control Station is located on the Generator door.

Engine Control (4-position Control Switch) Lockout / Reset

Off / Cooldown

Synchronizing Mode Switch (4-position Switch)

Circuit Breaker Control Switches

The trip function on Circuit Breaker Control Switches is available at all times. Anytime a breaker is manually tripped, a device 86 lockout relay will be activated to prevent the PLC from re-closing the manually opened breaker. The device 86 status will be wired into the PLC so that the OIT can display the condition.

The manual close function of PLC controlled breakers is only enabled when the system is in Manual Mode or all PLC control has failed. Circuit breakers that are part of a transfer pair or tie breaker scheme will have interlocks in place to prevent the paralleling of sources by control switches.

Normal Mode

Whenever the Master local control switch is in the automatic position and each individual engine generator control switch is placed in their automatic position, the engine generator system is on standby in readiness for automatic starting and synchronization in the event of a power failure signal.

Emergency Mode

Loss of Preferred Single Utility (52U1)

Any time a Single Utility outage is sensed, the system will transfer the building load to the alternate utility source and the system will annunciate this condition as Emergency mode.

Switch Position: (note - switches not shown may be placed in any position)

With the switches in the above position, the system is in automatic mode and will operate per the following sequence:

A loss of utility source is detected on the line side of the Utility 1 Main Circuit Breaker (52U1), as sensed by its respective SEL-751A multifunction protective relay [using devices 27/47/59/81], will initiate a transfer to the Utility 2 Source.

Note: A trip or lockout of the utility main circuit breaker (52U1) will prevent a subsequent source breaker from closing onto Bus A via tie circuit breakers A1/A2, utility main circuit breakers (52U1 or 52U2) or bus tie circuit breaker 52T if not already closed (ex. If the utility breaker trips, the alternate utility main circuit breaker or a tie circuit breaker will not be closed to feed load; however, Bus B will allowed to be energized per paragraph 3.5). This is to prevent closing into an existing fault.

· Upon loss of Utility Service, the controller will initiate a “Time Delay on Normal Fail” time delay (adjustable 0-120 seconds; factory default 2 sec).

· Upon expiration of the time delay, , the Utility 1 Main Circuit Breaker 52U1 will be opened.

· The delayed transition time delay shall begin and upon expiration, Tthe Utility 2 Main Circuit Breaker 52U2 will be closed.

Possible Failure Scenarios

· Utility 1 Main Circuit Breaker 52U1 Fail To Open: The condition will be annunciated. The 52U2, 52T, 52A1 and 52A2 circuit breakers will be inhibited from closing. Once confirmation is received that the breaker is open, any sequence requiring closure of these circuit breakers will continue. The condition can be reset at any time.

· Utility 2 Main Circuit Breaker 52U2 Fail To Close: The condition will be annunciated. The system will initiate transfer to the generator source per paragraph 3.5. The condition can be reset at any time.

Return from Loss of Preferred Single Utility (52U1) or Transfer to Utility Source 1

A “Utility Restore” time delay (adjustable 0-60 minutes; factory default 30 min) will initiate. Upon expiration of the time delay, the following sequences will occur:

NOTE: The operator can initiate the following sequences by placing the preferred utility source in the ‘52U1’ position initiating the transfer.

Closed Transition Mode

· The generators will be signaled to start.

· The first generator set to achieve 90% of nominal voltage and a frequency above 59Hz shall be connected to the bus (via generator paralleling circuit breaker 52Gx).

· As each subsequent generator achieves synchronism, it will be connected to the bus via its generator paralleling circuit breaker (52Gx).

· Once the required number of generators are connected to Bus C (adjustable 1-64, factory set at 2), the generators will be synchronized to the Utility 2 Source at the line side of the Utility 2 Main Circuit Breaker 52U2.

· Upon achieving synchronization, the Tie Circuit Breakers 52TB2 will be closed, if open.

· Tie Circuit Breaker 52T will be closed and Utility 2 Main Circuit Breaker 52U2 will be opened.

NOTE: The closed transition time will not exceed 100ms.

· The generators will be synchronized to the Utility 1 Source at the line side of the Utility 1 Main Circuit Breaker 52U1.

· Upon achieving synchronization, the Utility 1 Main Circuit Breaker 52U1 will be closed and the Tie Circuit Breaker 52T will be opened.

NOTE: The closed transition time will not exceed 100ms.

· The Tie Circuit Breaker 52TB2 will be opened.

· Generator Circuit Breakers 52G1-52G64 will be opened and the generators will run through cooldown and shutdown.

Possible Failure Scenarios

· Fail to Synchronize To Utility: The condition will be annunciated and the system will continue in attempts to synchronize until the sequence is aborted by the operator or one of the sources in the transfer scheme loses availability. NOTE: The operation may also be bypassed by placing the transition mode selector switch to the ‘Open’ position, allowing an open transition transfer return to utility operation or by placing the preferred source selector switch in the alternate position and initiating a transfer to the alternate utility source.

· Required Number of Generators Fail To Connect: The condition will be annunciated. The sequence will be aborted and the system will remain on the Utility 2 Source. The condition can be reset at any time. NOTE: The operator can initiate an open transition transfer to the Utility 2 Source by placing the transition mode selector switch in the ‘Open’ position and initiating the transfer.

· Tie Circuit Breaker 52T2 Fail To Close: The condition will be annunciated. The sequence will be aborted and the system will remain on the Utility 2 Source. The condition can be reset at any time.

· Tie Circuit Breaker 52T Fail To Close: The condition will be annunciated. The sequence will be aborted and the system will remain on the Utility 2 Source. The condition can be reset at any time.

· Utility 2 Main Circuit Breaker 52U2 Fail To Open: The condition will be annunciated. The sequence will be aborted and the system will remain on the Utility 2 Source. The condition can be reset at any time.

· Utility 1 Main Circuit Breaker 52U1 Fail To Close: The condition will be annunciated. The sequence will be aborted and the system will remain on the generator source. NOTE: The operator can initiate a transfer to the Utility 2 Source by placing the preferred source selector switch in the ‘52U2’ position and initiating the transfer.

· Tie Circuit Breaker 52T Fail to Open: The condition will be annunciated. The Tie Circuit Breaker 52TB2 will be opened and the sequence will continue. If a subsequent failure occurs at the Tie Circuit Breaker 52TB2, Tie Circuit Breaker 52TB1 will be opened and the sequence will continuethe Utility 1 Main Circuit Breaker 52U1 will be tripped open and the system will remain connected to the generator source. The condition can be reset at any time.

Open Transition Mode

· The Utility 2 Main Circuit Breaker 52U2 will be opened.

· The delayed transition time delay will begin.

· Upon expiration of the time delay, the Utility 1 Main Circuit Breaker 52U1 will be closed.

Possible Failure Scenarios

· Utility 2 Main Circuit Breaker Fail To Open: The condition will be annunciated. The sequence will be aborted and the system will remain connected to the Utility 2 Source. The condition can be reset at any time.

· Utility 1 Main Circuit Breaker Fail To Close: The condition will be annunciated. The Utility 2 Main Circuit Breaker 52U2 will be closed and the system will be re-energized with the Utility 2 Source. If a subsequent failure occurs at the Utility Main Circuit Breaker 52U2, the system will enter emergency mode per paragraph 3.5. The condition can be reset at any time.

Loss of Preferred Single Utility (52U2)

Any time a Single Utility outage is sensed, the system will transfer the building load to the alternate utility source and the system will annunciate this condition as Emergency mode.

Switch Position: (note - switches not shown may be placed in any position)

With the switches in the above position, the system is in automatic mode and will operate per the following sequence:

A loss of utility source is detected on the line side of the Utility 2 Main Circuit Breaker (52U2), as sensed by its respective SEL-751A multifunction protective relay [using devices 27/47/59/81], will initiate a transfer to the Utility 1 Source.

Note: A trip or lockout of the utility main circuit breaker (52U2) will prevent a subsequent source breaker from closing onto Bus A via tie circuit breakers A1/A2, utility main circuit breakers (52U1 or 52U2) or bus tie circuit breaker 52T if not already closed (ex. If the utility breaker trips, the alternate utility main circuit breaker or a tie circuit breaker will not be closed to feed load; however, Bus B will allowed to be energized per paragraph 3.5). This is to prevent closing into an existing fault.

· Upon loss of Utility Service, the controller will initiate a “Time Delay on Normal Fail” time delay (adjustable 0-120 seconds; factory default 2 sec).

· Upon expiration of the time delay, the Utility 2 Main Circuit Breaker 52U2 will be opened.

· The delayed transition time delay shall begin and upon expiration, Tthe Utility 1 Main Circuit Breaker 52U1 will be closed.

Possible Failure Scenarios

· Utility 2 Main Circuit Breaker 52U2 Fail To Open: The condition will be annunciated. The 52U1, 52T, 52A1 and 52A2 circuit breakers will be inhibited from closing. Once confirmation is received that the breaker is open, any sequence requiring closure of these circuit breakers will continue. The condition can be reset at any time.

· Utility 1 Main Circuit Breaker 52U1 Fail To Close: The condition will be annunciated. The system will initiate transfer to the generator source per paragraph 3.5. The condition can be reset at any time.

Return from Loss of Preferred Single Utility (52U2) or Transfer to Utility Source 2

A “Utility Restore” time delay (adjustable 0-60 minutes; factory default 30 min) will initiate. Upon expiration of the time delay, the following sequences will occur:

NOTE: The operator can initiate the following sequences by placing the preferred utility source in the ‘52U2’ position initiating the transfer.

Closed Transition Mode

· The generators will be signaled to start.

· The first generator set to achieve 90% of nominal voltage and a frequency above 59Hz shall be connected to the bus (via generator paralleling circuit breaker 52Gx).

· As each subsequent generator achieves synchronism, it will be connected to the bus via its generator paralleling circuit breaker (52Gx).

· Once the required number of generators are connected to Bus C (adjustable 1-64, factory set at 2), the generators will be synchronized to the Utility 1 Source at the line side of the Utility 1 Main Circuit Breaker 52U1.

· Upon achieving synchronization, the Tie Circuit Breakers 52TB2 will be closed, if open.

· Tie Circuit Breaker 52T will be closed and Utility 1 Main Circuit Breaker 52U1 will be opened.

NOTE: The closed transition time will not exceed 100ms.

· The generators will be synchronized to the Utility 2 Source at the line side of the Utility 2 Main Circuit Breaker 52U2.

· Upon achieving synchronization, the Utility 2 Main Circuit Breaker 52U2 will be closed and the Tie Circuit Breaker 52T will be opened.

NOTE: The closed transition time will not exceed 100ms.

· The Tie Circuit Breaker 52TB2 will be opened.

· Generator Circuit Breakers 52G1-52G64 will be opened and the generators will run through cooldown and shutdown.

Possible Failure Scenarios

· Fail to Synchronize To Utility: The condition will be annunciated and the system will continue in attempts to synchronize until the sequence is aborted by the operator or one of the sources in the transfer scheme loses availability. NOTE: The operation may also be bypassed by placing the transition mode selector switch to the ‘Open’ position, allowing an open transition transfer return to utility operation or by placing the preferred source selector switch in the alternate position and initiating a transfer to the alternate utility source.

· Required Number of Generators Fail To Connect: The condition will be annunciated. The sequence will be aborted and the system will remain on the Utility 1 Source. The condition can be reset at any time. NOTE: The operator can initiate an open transition transfer to the Utility 1 Source by placing the transition mode selector switch in the ‘Open’ position and initiating the transfer.

· Tie Circuit Breaker 52TB2 Fail To Close: The condition will be annunciated. The sequence will be aborted and the system will remain on the Utility 1 Source. The condition can be reset at any time.

· Tie Circuit Breaker 52T Fail To Close: The condition will be annunciated. The sequence will be aborted and the system will remain on the Utility 1 Source. The condition can be reset at any time.

· Utility 1 Main Circuit Breaker 52U1 Fail To Open: The condition will be annunciated. The sequence will be aborted and the system will remain on the Utility 1 Source. The condition can be reset at any time.

· Utility 2 Main Circuit Breaker 52U2 Fail To Close: The condition will be annunciated. The sequence will be aborted and the system will remain on the generator source. NOTE: The operator can initiate a transfer to the Utility 1 Source by placing the preferred source selector switch in the ‘52U1’ position and initiating the transfer.

· Tie Circuit Breaker 52T Fail to Open: The condition will be annunciated. The Tie Circuit Breaker 52TB2 will be opened and the sequence will continue. If a subsequent failure occurs at the Tie Circuit Breaker 52TB2, Tie Circuit Breaker 52TB1 will be opened and the sequence will continuethe Utility 2 Main Circuit Breaker 52U2 will be tripped open and the system will remain connected to the generator source. The condition can be reset at any time.

Open Transition Mode

· The Utility 1 Main Circuit Breaker 52U1 will be opened.

· The delayed transition time delay will begin.

· Upon expiration of the time delay, the Utility 2 Main Circuit Breaker 52U2 will be closed.

Possible Failure Scenarios

· Utility 1 Main Circuit Breaker 52U1 Fail To Open: The condition will be annunciated. The sequence will be aborted and the system will remain connected to the Utility 1 Source. The condition can be reset at any time.

· Utility 2 Main Circuit Breaker 52U2 Fail To Close: The condition will be annunciated. The Utility 1 Main Circuit Breaker 52U1 will be closed and the system will be re-energized with the Utility 1 Source. If a subsequent failure occurs at the Utility Main Circuit Breaker 52U1, the system will enter emergency mode per paragraph 3.5. The condition can be reset at any time.

Loss of Dual Utility at Switchgear GPS-1 (Sensed by SEL-751A)

Any time a Dual Utility outage is sensed and/or Generators are called to start in anticipation of feeding building load, the system will annunciate this condition as Emergency mode.

In Emergency Mode, all generator(s) automatically start and come up to speed. The first generator set to achieve 90% of nominal voltage and a frequency above 59Hz shall be connected to the bus. Electronic interlocks permit the connection of only one engine generator to the dead generator bus in the event of simultaneous generator relay operation. After the bus is energized by the first generator, the generator synchronizers will automatically adjust the frequency of the next on-coming generator to synchronize with the bus. When synchronism is achieved, the on-coming generator is paralleled to the bus. The generators connected to the bus will all share load and VARs proportionally.

Switch Position: (note - switches not shown may be placed in any position)

With the switches in the above position, the system is in automatic mode and will operate per the following sequence:

A dual loss of utility source is detected on the line side of the Utility 1 Main Circuit Breaker (52U1) and Utility 2 Main Circuit Breaker (52U2), as sensed by their respective SEL-751A multifunction protective relay [using devices 27/47/59/81], will initiate a transfer to the generator source.

Note: A trip or lockout of the utility main circuit breaker (52U1 or 52U2) will prevent a subsequent source breaker from closing onto Bus A via tie circuit breakers A1/A2, utility main circuit breakers (52U1 or 52U2) or bus tie circuit breaker 52T if not already closed (ex. If the utility breaker trips, the alternate utility main circuit breaker or a tie circuit breaker will not be closed to feed load; however, Bus B will allowed to be energized). This is to prevent closing into an existing fault.

· Upon loss of Utility Service, the controller will initiate a “Time Delay on Normal Fail” time delay (adjustable 0-120 seconds; factory default 2 sec).

· Upon expiration of the time delay, the controller will issue a start signal to the generators, the utility main circuit breakers (52U1 and 52U2) will be opened and all Bus A distribution breakers (52A1 – 52A3) will be opened.

· If the generator system was undergoing to load bank test, the load bank breaker (52LB) will be signaled to open and a load dump signal will be issued to the load bank.

· The first generator set to achieve 90% of nominal voltage and a frequency above 59Hz shall be connected to the bus (via generator paralleling circuit breaker 52Gx). Upon connection of the first generator to the bus, the tie circuit breaker (52TB2) will be closed, if open, and priority 1 & 2 ATSs will be connected to the emergency source.

· As each subsequent generator achieves synchronism, it will be connected to the bus via its generator paralleling circuit breaker (52Gx) allowing the next priority to connect to the bus (i.e. 52B3 to allow priority 3 ATSs to connect to the emergency source).

· If bus optimization is set to ‘On’, all loads not currently connected will be connected if capacity allows via paragraph 6.2.

· Once all ATSs have been connected to the emergency source, the system will attempt to “bus optimize” the GPS-1 Bus A.

· If remaining capacity allows, the 52T circuit breaker will be closed and the Bus A distribution circuit breakers (52A1-A3) will be closed per their priority and step timer. NOTE: If the Bus A is connected to the generatoremergency source, the ATSs will be signaled to remain on the emergency source via ASCO feature 17.

· If a failure occurs at the Chiller Plant (GPS-2) and the chiller plant generators are unable to connect to the GPS-2 bus, the chiller plant will also be “bus optimized” per paragraph 6.2. Otherwise, the chiller plant will be inhibited from closing its utility main circuit breaker unless extended outage mode is initiated.

Possible Failure Scenarios

· Utility Main Circuit Breaker (52U1 or 52U2) Fail to Open: The condition will be annunciated. The 52T , 52A1 and 52A2 tie circuit breakers will be inhibited from closing. Once confirmation is received that the breaker is open, any sequence requiring closure of thisese tie circuit breakers will continue. The condition can be reset at any time.

· Tie Circuit Breaker (52TB2) Fail To Close (If Open): The condition will be annunciated. The system will attempt to energize Bus B by closing tie breakers 52TA1, 52TA2 and 52T. The sequence will continueBus B will remain de-energized until the Tie Circuit Breaker 52T2 can be closed. The condition can be reset at any time.

· Load bank breaker (52B1) Fail to Open: The condition will be annunciated. A load dump signal will be sent to the load bank and the sequence will continue.

· Generator Fail To Connect: The condition will be annunciated. The sequence will continue. The condition can be reset at any time.

· Distribution Circuit Breaker Fail To Close (52A1-A3, 52B1-B3): The condition will be annunciated. The sequence will continue. The condition can be reset at any time.

· Distribution Circuit Breaker Fail To Open (52A1-A3): The condition will be annunciated. The system will inhibit closure of the Tie Circuit Breaker 52T. unless a subsequent fail to close condition occurs at the Tie Circuit Breaker 52TB2. The sequence will continue. The condition can be reset at any time.

Return from Loss of Dual Utility at GPS-1 Switchgear with ‘52U1’ Selected as the Preferred Utility Source (Sensed by SEL-751A)

A “Utility Restore” time delay (adjustable 0-60 minutes; factory default 30 min) will initiate. Upon expiration of the time delay, the following sequences will occur:

Closed Transition Mode (Connected via 52T)

· The generators will be synchronized to the Utility Source at the line side of the Utility 1 Main Circuit Breaker 52U1.

· Upon achieving synchronization, the Utility 1 Main Circuit Breaker 52U1 will be closed and the Tie Circuit Breaker 52T will be opened.

NOTE: The closed transition time will not exceed 100ms.

· The Bus A Distribution Circuit Breakers 52A1-52A3 will be closed (if not already closed)

· The ATSs will be released to connect to the normal source (via ASCO feature 17).

· Once all ATSs have connected to the normal source, Distribution Circuit Breakers 52B31-52B63 and Tie Circuit Breaker 52TB2 will be opened.

· The chiller plant return to normal inhibit is released.

· Generator Circuit Breakers 52G1-52G64 will be opened and the generators will run through cooldown and shutdown.

Possible Failure Scenarios

· Fail to Synchronize To Utility: The condition will be annunciated and the system will continue in attempts to synchronize until the sequence is aborted by the operator or one of the sources in the transfer scheme loses availability. NOTE: The operation may also be bypassed by placing the transition mode selector switch to the ‘Open’ position, allowing an open transition transfer return to utility operation or by placing the preferred source selector switch in the ‘52U2’ position and initiating a transfer to the Utility 2 source.

· Utility 1 Main Circuit Breaker 52U1 Fail To Close: The condition will be annunciated. The system will remain on the generator source. The condition can be reset at any time. NOTE: The operator can initiate a transfer to the Utility 2 Source (if available) by placing the Preferred Utility Source Selector Switch in the ‘52U2’ position and initiating the transfer.

· Tie Circuit Breaker 52T Fail To Open: The condition will be annunciated. The Utility 1 Main Circuit Breaker 52U1 will be opened and the system will remain on the generator sourceThe Tie Circuit Breaker 52T2 will be tripped open. If a subsequent failure occurs at Tie Circuit Breaker 52T2, the Utility 1 Main Circuit Breaker 52U1 will be tripped open and the system will remain connected to the generator source. The condition can be reset at any time.

· Distribution Circuit Breaker 52A1-A3 Fail To Close: The condition will be annunciated. The sequence will continue. The condition can be reset at any time.

· Distribution Circuit Breaker 52B31-52B63 Fail To Open: The condition will be annunciated. The sequence will continue. The condition can be reset at any time.

· Tie Circuit Breaker 52TB2 Fail To Open: The condition will be annunciated. The sequence will continue. The condition can be reset at any time.

Closed Transition Mode (Connected via 52TA1/A2)

· The generators will be synchronized to the Utility Source at the line side of the Utility 1 Main Circuit Breaker 52U1.

· Upon achieving synchronization, the Utility Main Circuit Breaker 52U1 will be closed and the Tie Circuit Breakers 52TA1 and 52TA2 will be opened.

NOTE: The closed transition time will not exceed 100ms.

· The Bus A Distribution Circuit Breakers 52A1-52A3 will be closed (if not already closed).

· The ATSs will be released to connect to the normal source (via ASCO feature 17).

· Once all ATSs have connected to the normal source, Distribution Circuit Breakers 52B1-52B3 and Tie Circuit Breaker 52T will be opened.

· The chiller plant return to normal inhibit is released.

· Generator Circuit Breakers 52G1-52G4 will be opened and the generators will run through cooldown and shutdown.

Possible Failure Scenarios

· Fail to Synchronize To Utility: The condition will be annunciated and the system will continue in attempts to synchronize until the sequence is aborted by the operator or one of the sources in the transfer scheme loses availability. NOTE: The operation may also be bypassed by placing the transition mode selector switch to the ‘Open’ position, allowing an open transition transfer return to utility operation or by placing the preferred source selector switch in the ‘52U2’ position and initiating a transfer to the Utility 2 source.

· Utility 1 Main Circuit Breaker 52U1 Fail To Close: The condition will be annunciated. The system will remain on the generator source. The condition can be reset at any time. NOTE: The operator can initiate a transfer to the Utility 2 Source (if available) by placing the Preferred Utility Source Selector Switch in the ‘52U2’ position and initiating the transfer.

· Tie Circuit Breaker 52TA1/52TA2 Fail To Open: The condition will be annunciated. If only a single Tie Circuit Breaker 52TA1 or 52TA2 fails to open, the sequence will continue. If both Tie Circuit Breakers 52TA1 and 52TA2 fail to open, the Utility Main Circuit Breaker 52U1 will be opened and the system will remain on the generator source. The condition can be reset at any time.

· Distribution Circuit Breaker 52A1-A3 Fail To Close: The condition will be annunciated. The sequence will continue. The condition can be reset at any time.

· Distribution Circuit Breaker 52B1-52B3 Fail To Open: The condition will be annunciated. The sequence will continue. The condition can be reset at any time.

Open Transition Mode (Connected via 52T)

· The Tie Circuit Breaker 52T will be opened.

· The Delayed transition time delay will begin (adjustable 0-30seconds, factory set at 5 seconds) and, upon expiration, the Utility 1 Main Circuit Breaker 52U1 will be closed.

· The Bus A Distribution Circuit Breakers 52A1-52A3 will be closed (if not already closed).

· The ATSs will be released to connect to the normal source (via ASCO feature 17).

· Once all ATSs have connected to the normal source, Distribution Circuit Breakers 52B32-52B63 and Tie Circuit Breaker 52TB2 will be opened.

· The chiller plant return to normal inhibit is released.

· Generator Circuit Breakers 52G1-52G64 will be opened and the generators will run through cooldown and shutdown.

Possible Failure Scenarios

· Utility 1 Main Circuit Breaker 52U1 Fail To Close: The condition will be annunciated. If the Utility 2 Source is available, the system will energize Bus A with the Utility 2 Source by closing the Utility 2 Main Circuit Breaker (52U2). If the Utility 2 Source is unavailable or a subsequent Fail To Close occurs at the Utility 2 Main Circuit Breaker (52U2), then the Bus A Distribution Circuit Breakers will be opened and the system will attempt to re-add the Bus A loads per paragraph 6.2. The condition can be reset at any time.

· Tie Circuit Breaker 52T Fail To Open: The condition will be annunciated. The Tie Circuit Breaker 52T2 will be tripped open and Tthe sequence will continue. If a subsequent failure occurs at 52T2, the system will remain connected to the generator source. The condition can be reset at any time.

· Distribution Circuit Breaker 52A1-A3 Fail To Close: The condition will be annunciated. The sequence will continue. The condition can be reset at any time.

· Distribution Circuit Breaker 52B31-52B63 Fail To Open: The condition will be annunciated. The sequence will continue. The condition can be reset at any time.

· Tie Circuit Breaker 52TB2 Fail To Open: The condition will be annunciated. The sequence will continue. The condition can be reset at any time.

Open Transition Mode (Connected via 52TA1/A2)

· The Tie Circuit Breakers 52TA1 and 52TA2 will be opened.

· The Delayed transition time delay will begin (adjustable 0-30seconds, factory set at 5 seconds) and, upon expiration, the Utility 1 Main Circuit Breaker 52U1 will be closed.

· The Bus A Distribution Circuit Breakers 52A1-52A3 will be closed (if not already closed).

· The ATSs will be released to connect to the normal source (via ASCO feature 17).

· Once all ATSs have connected to the normal source, Distribution Circuit Breakers 52B2-52B3 and Tie Circuit Breaker 52T will be opened.

· The chiller plant return to normal inhibit is released.

· Generator Circuit Breakers 52G1-52G4 will be opened and the generators will run through cooldown and shutdown.

Possible Failure Scenarios

· Utility 1 Main Circuit Breaker 52U1 Fail To Close: The condition will be annunciated. If the Utility 2 Source is available, the system will energize Bus A with the Utility 2 Source by closing the Utility 2 Main Circuit Breaker (52U2). If the Utility 2 Source is unavailable or a subsequent Fail To Close occurs at the Utility 2 Main Circuit Breaker (52U2), then the Bus A Distribution Circuit Breakers will be opened (if closed) and the system will attempt to re-add the Bus A loads per paragraph 6.2. The condition can be reset at any time.

· Tie Circuit Breaker 52T Fail To Open: The condition will be annunciated. The sequence will continue. The condition can be reset at any time.

· Distribution Circuit Breaker 52A1-A3 Fail To Close: The condition will be annunciated. The sequence will continue. The condition can be reset at any time.

· Distribution Circuit Breaker 52B1-52B3 Fail To Open: The condition will be annunciated. The sequence will continue. The condition can be reset at any time.

· Tie Circuit Breakers 52TA1 and 52TA2 Fail To Open: The condition will be annunciated. The sequence will remain on the generator source. The condition can be reset at any time.

Return from Loss of Dual Utility at GPS-1 Switchgear with ‘52U2’ Selected as the Preferred Utility Source (Sensed by SEL-751A)

A “Utility Restore” time delay (adjustable 0-60 minutes; factory default 30 min) will initiate. Upon expiration of the time delay, the following sequences will occur:

Closed Transition Mode (Connected via 52T)

· The generators will be synchronized to the Utility 2 Source at the line side of the Utility 2 Main Circuit Breaker 52U2.

· Upon achieving synchronization, the Utility 2 Main Circuit Breaker 52U2 will be closed and the Tie Circuit Breaker 52T will be opened.

NOTE: The closed transition time will not exceed 100ms.

· The Bus A Distribution Circuit Breakers 52A1-52A3 will be closed (if not already closed)

· The ATSs will be released to connect to the normal source (via ASCO feature 17).

· Once all ATSs have connected to the normal source, Distribution Circuit Breakers 52B31-52B63 and Tie Circuit Breaker 52TB2 will be opened.

· The chiller plant return to normal inhibit is released.

· Generator Circuit Breakers 52G1-52G64 will be opened and the generators will run through cooldown and shutdown.

Possible Failure Scenarios

· Fail to Synchronize To Utility: The condition will be annunciated and the system will continue in attempts to synchronize until the sequence is aborted by the operator or one of the sources in the transfer scheme loses availability. NOTE: The operation may also be bypassed by placing the transition mode selector switch to the ‘Open’ position, allowing an open transition transfer return to utility operation or by placing the preferred source selector switch in the ‘52U1’ position and initiating a transfer to the Utility 1 source.

· Utility 2 Main Circuit Breaker 52U2 Fail To Close: The condition will be annunciated. The system will remain on the generator source. The condition can be reset at any time. NOTE: The operator can initiate a transfer to the Utility 1 Source (if available) by placing the Preferred Utility Source Selector Switch in the ‘52U1’ position and initiating the transfer.

· Tie Circuit Breaker 52T Fail To Open: The condition will be annunciated. The Utility 2 Main Circuit Breaker 52U2Tie Circuit Breaker 52T2 will be tripped opened and the sequence will continue. If a subsequent failure occurs at 52T2, the Utility 2 Main Circuit Breaker 52U2 will be tripped open and the system will remain on the generator source. The condition can be reset at any time.

· Distribution Circuit Breaker 52A1-A3 Fail To Close: The condition will be annunciated. The sequence will continue. The condition can be reset at any time.

· Distribution Circuit Breaker 52B31-52B63 Fail To Open: The condition will be annunciated. The sequence will continue. The condition can be reset at any time.

· Tie Circuit Breaker 52TB2 Fail To Open: The condition will be annunciated. The sequence will continue. The condition can be reset at any time.

Closed Transition Mode (Connected via 52TA1/A2)

· The generators will be synchronized to the Utility Source at the line side of the Utility 2 Main Circuit Breaker 52U2.

· Upon achieving synchronization, the Utility 2 Main Circuit Breaker 52U2 will be closed and the Tie Circuit Breakers 52TA1 and 52TA2 will be opened.

NOTE: The closed transition time will not exceed 100ms.

· The Bus A Distribution Circuit Breakers 52A1-52A3 will be closed (if not already closed).

· The ATSs will be released to connect to the normal source (via ASCO feature 17).

· Once all ATSs have connected to the normal source, Distribution Circuit Breakers 52B1-52B3 and Tie Circuit Breaker 52T will be opened.

· The chiller plant return to normal inhibit is released.

· Generator Circuit Breakers 52G1-52G4 will be opened and the generators will run through cooldown and shutdown.

Possible Failure Scenarios

· Fail to Synchronize To Utility: The condition will be annunciated and the system will continue in attempts to synchronize until the sequence is aborted by the operator or one of the sources in the transfer scheme loses availability. NOTE: The operation may also be bypassed by placing the transition mode selector switch to the ‘Open’ position, allowing an open transition transfer return to utility operation or by placing the preferred source selector switch in the ‘52U1’ position and initiating a transfer to the Utility 1 source.

· Utility 2 Main Circuit Breaker 52U2 Fail To Close: The condition will be annunciated. The system will remain on the generator source. The condition can be reset at any time. NOTE: The operator can initiate a transfer to the Utility 1 Source (if available) by placing the Preferred Utility Source Selector Switch in the ‘52U1’ position and initiating the transfer.

· Tie Circuit Breaker 52TA1/52TA2 Fail To Open: The condition will be annunciated. If only a single Tie Circuit Breaker 52TA1 or 52TA2 fails to open, the sequence will continue. If both Tie Circuit Breakers 52TA1 and 52TA2 fail to open, the Utility 2 Main Circuit Breaker 52U2 will be opened and the system will remain on the generator source. The condition can be reset at any time.

· Distribution Circuit Breaker 52A1-A3 Fail To Close: The condition will be annunciated. The sequence will continue. The condition can be reset at any time.

· Distribution Circuit Breaker 52B1-52B3 Fail To Open: The condition will be annunciated. The sequence will continue. The condition can be reset at any time.

Open Transition Mode (Connected via 52T)

· The Tie Circuit Breaker 52T will be opened.

· The Delayed transition time delay will begin (adjustable 0-30seconds, factory set at 5 seconds) and, upon expiration, the Utility 2 Main Circuit Breaker 52U2 will be closed.

· The Bus A Distribution Circuit Breakers 52A1-52A3 will be closed (if…