Often Overlooked Problems When Applying Automatic Transfer Switches

Often Overlooked Problems When Applying Automatic Transfer Switches in Institutions David G. Loucks, P. E. Dave. GLoucks@eaton. com Eaton Corporation © 2005 Eaton Corporation. All rights reserved.

We Will Cover: 1. Changes Forcing Us To Rethink Our Designs 1. Utility 2. Our Facilities 2. Need To Improve System Reliability 1. Selectivity / Coordination 2. Withstand / Short-Time 3. X/R ratings 3. “Optional Systems” 1. Unique Add-On Solutions 2

Changes: Background Survey l l l 1. How to Insure You Have It 2. How to Improve What You Have Electrical Utility Grid reliability or lack thereof Increased dependency in hospital on computer based devices Aging infrastructure – capacity, reliability, maintenance cost, parts availability, safety l Arc flash l Saving money; Reducing energy consumptions 3

Changes: Background Survey l l l Utility Grid reliability or lack thereof Increased dependency in hospital on computer based devices Aging infrastructure – capacity, reliability, maintenance cost, parts availability, safety l Arc flash l Saving money; Reducing energy consumptions Important Topics, but won’t be covered today 4

Okay, So What Affects Electrical Grid Reliability? l l l Surge Protection and Grounding Harmonics, Power Factor Correction & Electromagnetic interference Back-up Power and Voltage Stabilization (Power Conditioning) Monitoring and Diagnostic Systems (Early Warning) Human Issues 5

During Today’s Webinar We Will Focus on This Issue l l l Surge Protection and Grounding Harmonics, Power Factor Correction & Electromagnetic interference Back-up Power and Voltage Stabilization (Power Conditioning) Monitoring and Diagnostic Systems (Early Warning) Human Issues 6

How To Recognize You Have a Voltage Stability Problem l Problems / Symptoms – what problems can occur n Computer reboots / lock-ups n Lights flickering n Loss of revenue n User inconvenience & rescheduling n Diagnostic equipment recalibration requirements n Lost or destroyed samples / data / research n (Medical) Increased patient suffering n Data integrity n HVAC / comfort n Safety (biohazard, falls) n Increased equipment repair costs 7

What Causes Voltage Instability? l l l l Miscoordination of protective equipment System overload (Hospital) Lack of isolation panels – wet areas, gases Utility outages / natural disaster (i. e. Northeast blackout; weather issues; lack of fuel) Human error Bad batteries / battery failure Poor maintenance 8

Since our discussion deals with generators and ATS, we will cover: l l l l Miscoordination of protective equipment System overload (Hospital) Lack of isolation panels – wet areas, gases Utility outages / natural disaster (i. e. Northeast blackout; weather issues; lack of fuel) Human error Bad batteries / battery failure Poor maintenance 9

TESTING STANDARDS l UL 1008 ATS Standard l UL 489 l UL 1087 MCS Standard l UL 1066 PCB Standard l UL 891 l UL 1558 LV Switchgear Standard l Q. A. CERTIFICATE MCCB Standard LV Switchboard Standard n 50 Operations Minimum n Internal Production Standard 10

Low Voltage Power Circuit Breakers l l l ANSI C 37. 13 IEEE Standard for Low-Voltage AC Power Circuit Breakers Used in Enclosures ANSI C 37. 16 Low-Voltage Power Circuit Breakers and AC Power Circuit Protectors Preferred Ratings, Related Requirements, and Application Recommendations ANSI C 37. 17 Trip Devices for AC and General Purpose DC Low-Voltage Power Circuit Breakers 11

Healthcare: JCAHO EC. 2. 10. 4. 1 …testing each generator 12 times a year with testing intervals not less than 20 days and not more than 40 days. These tests shall be conducted for at least 30 continuous minutes under a dynamic load that is at least 30% of the nameplate rating of the generator. If diesel-powered generators do not meet the minimum exhaust gas temperatures as determined during these tests, they shall be exercised for 30 continuous minutes at the intervals described above with available EPSS load, and exercised annually with supplemental loads of • • • 25 percent of nameplate rating for 30 minutes, followed by 50 percent of nameplate rating for 30 minutes, followed by 75 percent of nameplate rating for 60 minutes for a total of two continuous hours. 12

Other Applicable Standards l NFPA 99 n l NFPA 110 n l “Standards for Healthcare Facilities” “Standards for Emergency and Standard Power Systems” IEEE 1547 Utility Interconnect Standard (NEW) n n Only applies if 10 MW or smaller (if larger, custom utility review required) Only if “Make-Before-Break” closed transition for more than 1/10 second with utility 13

Transfer Switches for Emergency Systems l l NEC Article 700 Legally required to automatically provide alternate power, within 10 seconds of power interruption, to a number of prescribed functions essential for the safety of human life 14

Transfer Switches for Legally Required Standby Systems l l l NEC Articles 701 Intended to automatically supply power to selected loads (other than those classed as emergency systems) in the event of failure of the normal source Power available 60 seconds after outage 15

Transfer Switches for Optional Standby Systems l l NEC Articles 702 Intended to supply power, either automatically or non-automatically to selected loads other than those classed as emergency or legally required standby 16

Miscoordination l Selective Coordination n l l Upstream and downstream breakers • Phase • Ground ATS withstand n Magnitude n Duration n Asymmetry (X/R) ATS short-time rating 17

Healthcare Ground Fault Protection -- NEC 517. 17 l l … an additional step of ground-fault protection shall be provided in the next level of feeder disconnecting means downstream toward the load. The additional levels of ground-fault protection shall not be installed as follows: n n (1) On the load side of an essential electrical system transfer switch (2) Between the on-site generating unit(s) described in 517. 35(B) and the essential electrical system transfer switch(es) 18

Healthcare Ground Fault Protection – UL 1008 Article 20 Exception No. 3: Ground-fault protection need not be provided on that side of a transfer switch intended for connection to the alternate source, provided that the transfer switch is marked in accordance with 41. 50. 19

2002 NEC 517. 17 Ground-Fault Protection B) Selectivity. Ground-fault protection for operation of the service and feeder disconnecting means shall be fully selective such that the feeder device and not the service device shall open on ground faults on the load side of the feeder device. A sixcycle minimum separation between the service and feeder ground-fault tripping bands shall be provided. 20

UL 1008 - ATS Withstand Fault Closing Ratings l l Transfer switch must withstand the designated level of short-circuit current until the overcurrent protective devices open (unless integral to the design) Test current specified in terms of the required symmetrical amperes and the power factor of the test current Test current maintained for at least three cycles (50 ms) Same sample used for the closing test 21

Definitions Interrupting capacity The Maximum Short Circuit Current that the Device Can Safely Interrupt Short-time current rating Defines the Ability of the Device to Remain Closed for a Time Interval Under High Fault Current Conditions 22

NEC 517. 17 Says Your Upstream Device Must Remain Closed For… B) Selectivity. Ground-fault protection for operation of the service and feeder disconnecting means shall be fully selective such that the feeder device and not the service device shall open on ground faults on the load side of the feeder device. A six-cycle minimum separation between the service and feeder ground-fault tripping bands shall be provided. 23

How Long Does UL 1008 Say ATS Must Withstand Fault? UL 1008 34 Withstand 34. 1 When tested under the conditions described in 34. 2 – 34. 15, a transfer switch shall withstand the designated levels of current until the overcurrent protective devices open or for a time as designated in 34. 3. At the conclusion of the test…. 34. 5 The test current is to be maintained for at least 3 cycles (50 ms). See 41. 20. 24

To Achieve Selectivity, You Need To Delay Upstream Device l l l A six-cycle separation between service and feeder means that at any current level, the downstream device must clear the fault 6 -cycles (0. 1 sec) faster than the upstream device. If the fault current is high, the downstream device might be clearing it in 0. 02 seconds (~1 cycle) That means the upstream must delay tripping for 6+1 = 7 cycles = 0. 12 seconds 25

Can an ATS Withstand a Fault for 0. 12 seconds? l Not if the switch is only UL 1008 rated for 3 -cycles. l “Houston, we have a problem…” 26

Fast Forward to 2002: New UL 1008 41. 20. 1 Short-Time 3 Cycle ATS 41. 20 A transfer switch tested for three cycles shall be marked, When protected by a circuit breaker without an adjustable short-time response only or by fuses this transfer switch is rated for use on a circuit capable of delivering not more than ____ rms symmetrical amperes, ____ volts maximum. ² The value of amperes shall correspond to the symmetrical values given in 41. 23. See 34. 5 and 34. 6. Revised 41. 20 effective September 18, 1997 Short-Time Rated ATS 41. 20. 1 A transfer switch determined to comply with the Short-Time Current Rating Test, Section 36 A, shall be marked, ²This transfer switch is intended for use with an upstream circuit breaker having a short-time rating not exceeding _______ volts at ______ amperes, for _______ cycles (seconds). ² The values of amperes, and cycles (seconds) shall be as specified by the manufacturer. 41. 20. 1 added January 9, 2002 27

Choose Carefully l l Make sure your ATS can survive 6 -cycles of fault current UL 1008 ATS Standard n n All are tested to 3 -cycles at their withstand current UL 1008 28. 1 -28. 6 says that ATS tested to 6 times rated current for 10 cycles If your calculated fault current is greater than 6 x ATS rating, you need an ATS with a short-time rating May also need to review your distribution equipment • UL 891 Switchboards/UL 489 Devices (3 -cycle rated) • UL 1558 Switchgear/UL 1066 Devices (30 -cycle rated) 28

Power Factor 29

X/R Ratio 30

X/R Ratio - ANSI Test X/R = 0, PF = 1. 0 (symmetry) X/R = 6. 6, PF = 0. 15 (asymmetry) Current in Per Unit 20 15 10 5 0 0 1 2 3 4 -5 -10 Time in Cycles 31

X/R Ratio - Application Data UL 1008 takes these values into consideration, so ATS is okay …but when specifying generator breaker make sure you are aware of these derating factors 32

X/R Ratio - Application Data Peak Multiplication Factor Calculations Z X R X/R = tan-1(X/R) R/Z = cos = PF = cos-1(PF) X/R = tan(cos-1(PF)) PF = cos(tan-1(X/R)) 33

LVPCB Application – Large Source KVA G At 2500 KVA I (sc) = 64, 300 A Utility 4000 A PCB 1600 A ATS 800 A PCB 600 A MCB 34

Typical Distribution System -- Possible Fault Locations -Gen 1 Utility > 1000 A > 150 VLN CB 1 CB 2 F 1 S 2 control logic F 2 F 3 35

Fault Cleared by Upstream Device Gen 1 Utility Event Breaker Type Contactor Type Comparison Between Designs > 1000 A > 150 VLN CB 1 CB 2 F 1 S 2 control logic 36

Fault Cleared by Upstream Device Gen 1 Utility Event Breaker Type Contactor Type Comparison Between Designs (F 1) Fault on load side of CB 1 (line side of ATS) > 1000 A > 150 VLN CB 1 CB 2 F 1 S 2 control logic 37

Fault Cleared by Upstream Device Gen 1 Utility > 1000 A > 150 VLN CB 1 Event Breaker Type Contactor Type (F 1) Fault on load side of CB 1 (line side of ATS) Fault drops S 1 voltage to low value Comparison Between Designs Same CB 2 F 1 S 2 control logic 38

Fault Cleared by Upstream Device Gen 1 Utility > 1000 A > 150 VLN Trips! CB 1 CB 2 Comparison Between Designs Event Breaker Type Contactor Type (F 1) Fault on load side of CB 1 (line side of ATS) Fault drops S 1 voltage to low value Same CB 1 opens S 1 voltage drops to zero Same F 1 S 2 control logic 39

Fault Cleared by Upstream Device Gen 1 Utility > 1000 A > 150 VLN CB 1 S 1 Event Breaker Type Contactor Type (F 1) Fault on load side of CB 1 (line side of ATS) Fault drops S 1 voltage to low value Same CB 1 opens S 1 voltage drops to zero Same CB 2 ATS calls for Gen 1 start F 1 Comparison Between Designs - - Same S 2 control logic 40

Fault Cleared by Upstream Device Gen 1 Utility > 1000 A > 150 VLN CB 1 S 1 Event Breaker Type Contactor Type (F 1) Fault on load side of CB 1 (line side of ATS) Fault drops S 1 voltage to low value Same CB 1 opens S 1 voltage drops to zero Same CB 2 ATS calls for Gen 1 start F 1 S 2 control logic Comparison Between Designs ATS transfers to S 2 Voltage appears on S 2 Same System Functioning Normally 41

Fault Moved to Load Side of ATS Gen 1 Utility > 1000 A > 150 VLN CB 1 CB 2 S 1 S 2 control logic F 2 42

Fault Moved to Load Side of ATS Gen 1 Utility Event Breaker Type Contactor Type Comparison Between Designs > 1000 A > 150 VLN CB 1 CB 2 S 1 S 2 control logic F 2 43

Fault Moved to Load Side of ATS Gen 1 Utility > 1000 A > 150 VLN CB 1 Event Breaker Type Contactor Type (F 2) Fault on load side ATS) Fault drops S 1 voltage to low value Comparison Between Designs Same CB 2 S 1 S 2 control logic F 2 44

Fault Moved to Load Side of ATS Gen 1 Utility > 1000 A > 150 VLN Trips! CB 1 CB 2 S 1 Comparison Between Designs Event Breaker Type Contactor Type (F 2) Fault on load side ATS) Fault drops S 1 voltage to low value Same CB 1 opens S 1 voltage drops to zero Same S 2 control logic F 2 45

Fault Moved to Load Side of ATS Gen 1 Utility > 1000 A > 150 VLN CB 1 Event Breaker Type Contactor Type (F 2) Fault on load side ATS) Fault drops S 1 voltage to low value Same CB 1 opens S 1 voltage drops to zero Same CB 2 ATS calls for Gen 1 start S 1 Comparison Between Designs - - Integrated selfprotects S 2 control logic F 2 46

Fault Moved to Load Side of ATS Gen 1 Utility > 1000 A > 150 VLN CB 1 Event Breaker Type Contactor Type (F 2) Fault on load side ATS) Fault drops S 1 voltage to low value Same CB 1 opens S 1 voltage drops to zero Same CB 2 ATS calls for Gen 1 start S 1 S 2 Comparison Between Designs ATS transfers to S 2 Voltage appears on S 2 Integrated selfprotects control logic F 2 47

Fault Moved to Load Side of ATS Gen 1 Utility > 1000 A > 150 VLN Trips! CB 1 Event Breaker Type Contactor Type (F 2) Fault on load side ATS) Fault drops S 1 voltage to low value Same CB 1 opens S 1 voltage drops to zero Same CB 2 ATS calls for Gen 1 start S 1 S 2 control logic Comparison Between Designs - - Integrated selfprotects ATS transfers to S 2 Voltage appears on S 2 Integrated selfprotects CB 2 opens Closing into fault trips CB 2 Integrated selfprotects F 2 48

Fault Moved to Load Side of ATS Gen 1 Utility > 1000 A > 150 VLN CB 1 Event Breaker Type Contactor Type (F 2) Fault on load side ATS) Fault drops S 1 voltage to low value Same CB 1 opens S 1 voltage drops to zero Same CB 2 ATS calls for Gen 1 start S 1 S 2 control logic F 2 Comparison Between Designs - - Integrated selfprotects ATS transfers to S 2 Voltage appears on S 2 Integrated selfprotects CB 2 opens Closing into fault trips CB 2 Integrated selfprotects No power to load Both sources tripped Same System Functioning Normally, but after F 2 fixed, CB 1 and CB 2 must be reset and reclosed 49

Alternate Design: Communications with Upstream Overcurrent Device Gen 1 Utility > 1000 A > 150 VLN CB 1 Phase trip unit S 1 CB 2 S 2 control logic L. O. F 2 50

Alternate Design: Communications with Upstream Overcurrent Device Gen 1 Utility Event Breaker Type (with integrated OC protection) Contactor Type Comparison Between Designs > 1000 A > 150 VLN CB 1 Phase trip unit S 1 CB 2 S 2 control logic L. O. F 2 51

Alternate Design: Communications with Upstream Overcurrent Device Gen 1 Utility Event Breaker Type Contactor Type Comparison Between Designs Fault drops S 1 voltage to low value Same (with integrated OC protection) > 1000 A > 150 VLN CB 1 (F 2) Fault on load side ATS) Phase trip unit S 1 Fault drops S 1 voltage to low value CB 2 S 2 control logic L. O. F 2 52

Alternate Design: Communications with Upstream Overcurrent Device Gen 1 Utility Event Breaker Type Contactor Type Comparison Between Designs (with integrated OC protection) > 1000 A > 150 VLN Trips! Phase CB 1 trip unit S 1 CB 2 (F 2) Fault on load side ATS) Fault drops S 1 voltage to low value Same CB 1 opens S 1 voltage drops to zero Same S 2 control logic L. O. F 2 53

Alternate Design: Communications with Upstream Overcurrent Device Gen 1 Utility Event Breaker Type Contactor Type Comparison Between Designs (with integrated OC protection) > 1000 A > 150 VLN CB 1 Phase trip unit S 1 CB 2 (F 2) Fault on load side ATS) Fault drops S 1 voltage to low value Same CB 1 opens S 1 voltage drops to zero Same ATS detects phase fault and locks out Locked out (but ready) - Same S 2 control logic L. O. F 2 54

Alternate Design: Communications with Upstream Overcurrent Device Gen 1 Utility Event Breaker Type Contactor Type Comparison Between Designs (with integrated OC protection) > 1000 A > 150 VLN CB 1 Phase trip unit S 1 CB 2 S 2 control logic L. O. (F 2) Fault on load side ATS) Fault drops S 1 voltage to low value Same CB 1 opens S 1 voltage drops to zero Same ATS detects phase fault and locks out Locked out (but ready) - Same System Functioning Normally, Integrated OC ATS will not try to close into downstream fault F 2 55

Fault Moved to Load Side of Downstream Feeder Breaker Gen 1 Utility > 1000 A > 150 VLN CB 1 CB 2 S 1 S 2 control logic CB 3 CB 4 CB 5 F 3 56

Fault Moved to Load Side of Downstream Feeder Breaker Gen 1 Utility > 1000 A > 150 VLN CB 1 Event Breaker Type Contactor Type (F 3) Fault on load side of CB 3 S 1 voltage drops (related to distance to F 3 fault) Comparison Between Designs Same CB 2 S 1 S 2 control logic CB 3 CB 4 CB 5 F 3 57

Fault Moved to Load Side of Downstream Feeder Breaker Gen 1 Utility > 1000 A > 150 VLN CB 1 CB 2 S 1 Comparison Between Designs Event Breaker Type Contactor Type (F 3) Fault on load side of CB 3 S 1 voltage drops (related to distance to F 3 fault) Same CB 5 opens CB 3, CB 4 loads continue with power Same S 2 control logic CB 3 CB 4 Trips! CB 5 F 3 58

Fault Moved to Load Side of Downstream Feeder Breaker Gen 1 Utility > 1000 A > 150 VLN CB 1 Event Breaker Type Contactor Type (F 3) Fault on load side of CB 3 S 1 voltage drops (related to distance to F 3 fault) Same CB 5 opens CB 3, CB 4 loads continue with power Same CB 2 Power is maintained to CB 3 and CB 4 S 1 Comparison Between Designs - - Same S 2 control logic CB 3 CB 4 CB 5 System Functioning Normally, only loads connected to CB 5 are affected F 3 59

ATS Response to Various Faults Location of Disturbance Type of Disturbance CB 1 Response CB 3 Response Instantaneous Trip Molded Case Switch ATS Response Magnum ATS Response Contactor Type ATS Response F 1 Overload Trip Nothing Start Gen, Transfer Start Gen, Transfer Short Circuit Trip Nothing Start Gen, Transfer Start Gen, Transfer GF Trip Nothing Start Gen, Transfer Start Gen, Transfer Overload Nothing Trip No Transfer Short Circuit (low magnitude) Nothing Trip No Transfer Short Circuit (high magnitude) Trip/ Nothing 1 Trip Start Gen, Transfer or No Transfer 2 GF (low magnitude) Nothing/ Trip 3 Nothing/ Trip 4 Start Gen, Transfer or No Transfer 5 GF (high magnitude) Trip/ Nothing 6 Trip Start Gen, Transfer or No Transfer 7 F 2 F 3 60

Notes 1. 2. 3. 4. 5. 6. 7. If the CB 1 breaker does not have short-time delay, and the fault magnitude is within its instantaneous range, CB 1 will trip. If CB 1 trips, ATS will interpret that as loss of Source 1, start generator and attempt to transfer. If fault remains, generator will close into fault and trip generator breaker (CB 2). If only breaker upstream of GF is utility main (CB 1), it will trip. If CB 3 has GF protection, and that GF protection is selectively coordinated with CB 1 (as it should be), CB 3 will trip and isolate the GF, CB 1 will not trip and the generator will not start and transfer. If CB 1 trips due to GF, the generator will start and transfer. Since the generator breaker does not require GF protection and since the GF is a “low magnitude” (i. e. below phase trip), generator will source power without tripping. If CB 1 does not have a time delay for ground fault trip, it may trip on a high magnitude GF. If CB 1 trips, the generator starts and transfers. 61

UL 1008 20. 1 GF Protection Utility Gen 1 B 1 S 1 B 2 S 2 control logic 62

GF Protection Gen 1 Utility > 1000 A > 150 VLN CB 1 S 1 CB 2 S 2 control logic 63

GF Protection Gen 1 Utility > 1000 A > 150 VLN GF required CB 1 S 1 CB 2 No GF required S 2 control logic 64

GF Protection Gen 1 Utility > 1000 A > 150 VLN 1. GF required CB 1 S 1 CB 2 Ground fault on system No GF required S 2 control logic 65

GF Protection Gen 1 Utility > 1000 A > 150 VLN Trip! CB 1 S 1 CB 2 No GF required 1. Ground fault on systems 2. B 1 trips on GF, ATS loses S 1, Gen 1 starts S 2 control logic 66

GF Protection Gen 1 Utility > 1000 A > 150 VLN Trip! CB 1 S 1 CB 2 S 2 control logic No GF required 1. Ground fault on systems 2. B 1 trips on GF, ATS loses S 1, Gen 1 starts 3. Transfers load to Gen 1. Depending on type of ground, 1 of 2 things happens: 67

GF Protection Gen 1 Utility > 1000 A > 150 VLN Trip! CB 1 S 1 1. Ground fault on systems 2. B 1 trips on GF, ATS loses S 1, Gen 1 starts 3. Transfers load to Gen 1. Depending on type of ground, 1 of 2 things happens: CB 2 S 2 control logic • GF current below phase trip: S 2 remains closed 68

GF Protection Gen 1 Utility > 1000 A > 150 VLN Trip! CB 1 S 1 1. Ground fault on systems 2. B 1 trips on GF, ATS loses S 1, Gen 1 starts 3. Transfers load to Gen 1. Depending on type of ground, 1 of 2 things happens: CB 2 S 2 control logic • GF current above phase trip: S 2 Trips! – No power to load 69

GF Protection Gen 1 Utility What if the process were 1. Ground fault on systems repeated, except had 2. B 1 that trips on GF, we ATS loses S 1, Gen 1 starts a phase to phase fault 3. Transfers load to Genthis 1. Depending on type of ground, 1 of 2 things happens: time? > 1000 A > 150 VLN Trip! B 1 S 1 B 2 S 2 control logic • GF current above phase trip: S 2 Trips! – No power to load 70

Phase Protection Gen 1 Utility What if the process were 1. Ground fault on systems repeated, except had 2. B 1 that trips on GF, we ATS loses S 1, Gen 1 starts a phase to phase fault 3. Transfers load to Genthis 1. Depending on type of ground, 1 of 2 things happens: time? > 1000 A > 150 VLN Trip! B 1 S 1 B 2 S 2 control logic • GF current above phase trip: S 2 Trips! – No power to load 71

Phase Protection Gen 1 Utility > 1000 A > 150 VLN 1. Phase and GF Phase CB 2 only CB 1 S 1 Phase fault on system S 2 control logic 72

Phase Protection Gen 1 Utility > 1000 A > 150 VLN Trip! Phase CB 2 only CB 1 S 1 1. Phase fault on system 2. B 1 trips on phase overcurrent, ATS loses S 1, Gen 1 starts S 2 control logic 73

Phase Protection Gen 1 Utility > 1000 A > 150 VLN Trip! Phase and GF Phase fault on system 2. B 1 trips on phase overcurrent, ATS loses S 1, Gen 1 starts 3. Transfers load to Gen 1. Phase CB 2 only CB 1 S 1 1. S 2 control logic 74

Phase Protection Gen 1 Utility > 1000 A > 150 VLN Trip! Phase and GF Phase fault on system 2. B 1 trips on phase overcurrent, ATS loses S 1, Gen 1 starts 3. Transfers load to Gen 1. 4. S 2 Trips! – No power to load Phase CB 2 only CB 1 S 1 1. S 2 control logic 75

Phase Protection Gen 1 Utility > 1000 A > 150 VLN Trip! Phase and GF Phase fault on system 2. B 1 trips on phase overcurrent, ATS loses S 1, Gen 1 starts 3. Transfers load to Gen 1. 4. S 2 Trips! – No power to load 5. Both B 1 and B 2 are tripped and locked out, requiring manual reset. Facility in dark. Phase CB 2 only CB 1 S 1 1. S 2 control logic 76

Phase/Ground Discrimination l l l How would you design the system so you don’t close the generator into a bolted fault? … but allow the generator to close into a ground fault… How could this be done? 77

Phase and GF Discrimination 1. Gen 1 Utility Install Trip Units with separate phase and ground trip outputs. > 1000 A > 150 VLN Phase only Phase and GF CB 1 S 1 trip unit CB 2 trip unit S 2 control logic Lockout 78

Phase and GF Discrimination Gen 1 Utility > 1000 A > 150 VLN 1. Install Trip Units with separate phase and ground trip outputs. 2. Connect Phase trip to lockout input of ATS control. Phase only Phase and GF CB 1 S 1 trip unit CB 2 trip unit S 2 control logic Lockout 79

Phase and GF Discrimination Gen 1 Utility > 1000 A > 150 VLN 1. Install Trip Units with separate phase and ground trip outputs. 2. Connect Phase trip to lockout input of ATS control. Phase CB 1 S 1 trip unit Ground Phase CB 2 trip unit Ground S 2 control logic Lockout or 80

Phase and GF Discrimination Gen 1 Utility > 1000 A > 150 VLN 1. Install Trip Units with separate phase and ground trip outputs. 2. Connect Phase trip to lockout input of ATS control. 3. Phase CB 1 S 1 trip unit Ground B 1 trips on phase overcurrent Phase CB 2 trip unit Ground S 2 control logic Lockout or 81

Phase and GF Discrimination Gen 1 Utility > 1000 A > 150 VLN 1. Install Trip Units with separate phase and ground trip outputs. 2. Connect Phase trip to lockout input of ATS control. Phase CB 1 S 1 trip unit Ground Phase CB 2 trip unit Ground 3. B 1 trips on phase overcurrent 4. Gen 1 does not start. Does not close into fault. Saves wear and tear on generator and transfer switch. S 2 control logic Lockout or 82

Phase and GF Discrimination Gen 1 Utility > 1000 A > 150 VLN Phase S 1 CB 1 trip unit Ground control logic S 2 CB 2 1. Install Trip Units with separate phase and ground trip outputs. 2. Connect Phase trip to lockout input of ATS control. Phase trip unit Lockout Ground or 3. B 1 trips on phase overcurrent 4. Gen 1 does not start. Does not close into fault. Saves wear and tear on generator and transfer switch. Incorporating the overcurrent within the transfer switch achieves desired result of not closing into phase fault 83

(Major Hospital), North Central US 21 -SEP-02 …in the case of ------ Hospital's power failure, which lasted an hour, a power line wound up carrying more than its normal load for four days, which melted a fuse. That set off a chain of events that wound up overloading the hospital's emergency generators, causing them to fail, too. Mark Enger, the hospital's president, said the power failure could have been life -threatening. The power dropped but didn't go out entirely. It dropped enough, however, to trigger the hospital's three emergency generators. But because of the way the system is wired, the generators' cooling fans failed to work, the generators overheated and the hospital lost all power at about 11 a. m. Enger said there were eight surgeries going when the power failed. Four of the surgeons were able to finish their operations, while the other four finished quickly and re-scheduled the surgeries for the next day. Partial power was restored by noon, and full power was restored the next day, Enger said. (The local utility) is adamant that its maintenance practices are not posing widespread service problems. But one (utility) worker said the hospital's power failure is but a symptom of the electrical grid's ill health. (St. Paul MN, Pioneer Press 8 -6 -2003) 84

(Major) Hospital On April 16, 2002, (---) Hospital lost power for an afternoon, leaving various parts of the 33 -building campus dark for varying amounts of time. At (----) building, an emergency generator immediately turned on, emergency lights came on, and no essential services were disrupted, according to a (local newspaper) article. However, at (the --- main) Hospital, the backup electric system did not work, prompting Mayor Vincent A. Cianci Jr. , to tell the (local paper), “A hospital of this magnitude and this size should not have these problems. ” Surprisingly, power outages do happen with alarming frequency to big hospitals. In fact, they’ve happened at (this) Hospital campus before. In September 1999, a blackout plunged the entire campus into darkness. The backup systems failed once again and this time a patient died after his respirator failed. Then, in January 2000, another power failure forced the hospital to rely on backup generators for nearly two hours and shut down nonessential equipment and lights. A faulty ceramic insulator at a substation on the hospital campus caused the failure. Then a damaged coil prevented some of the backup power from flowing back into one of the hospital buildings. (EC&M Magazine 8 -1 -2002) 85

Would You Classify These Loads As Critical or Essential? l l l Kitchen and dietary department? Radiology and associated cooling? Computer network (hubs, routers, servers)? Computer room cooling for servers? Fan and exhaust loads for biohazard containment? Chillers, air handlers, BMS, dampers, AF drives for patient and occupant comfort? 86

Would You Classify These Loads As Critical or Essential? l l l Kitchen and dietary department? Radiology and associated cooling? Computer network (hubs, routers, servers)? Computer room cooling for servers? Fan and exhaust loads for biohazard containment? Chillers, air handlers, BMS, dampers, AF drives for patient and occupant comfort? Article 702 Optional Standby Loads ? Background Case Studies Techniques Coordination ATS Designs Withstand PF and X/R Tips / Summary 87

06 -AUG-03 A power failure forced ------ Medical Center to shut its emergency room and turn away visitors and some patients yesterday, as the hospital staff struggled with limited use of the airconditioning, computers and other equipment. Chris Olert, a spokesman for (local utility), said, "We know that it was a combined failure of some of our equipment and some of the hospital's equipment, but we don't know exactly what triggered it. “ He said a cable feeding electricity to the medical center was damaged and had to be bypassed. When the power failed, the hospital's backup generators automatically turned on, but they could not carry the entire load, so hospital officials shut down some functions to preserve electricity for the most crucial ones. "No critical services were affected, " said Lynn Odell, a hospital spokeswoman. But hospital employees interviewed outside the building and family members of some patients said things were seriously disrupted for a time. One worker told of a darkened pharmacy with dormant computers, where pharmacists using flashlights filled out paperwork by hand responded to orders by telephone rather than computer. Another spoke of a stiflingly hot surgery department where some medicines spoiled in a nonworking refrigerator. (New York Times 8 -6 -2003) 88

2004 – Hurricane Charley l Power could not be restored to a regional hospital in Charlotte County Florida for 4 days n n Hospital only had 28 hours of fuel Fastest way was add trailer supplemental power • Had to cut hole near inlet damper for cables 89

2004 – Hurricane Charley l Power could not be restored to a regional hospital in Charlotte County Florida for 4 days n n Hospital only had 28 hours of fuel Fastest way was add trailer supplemental power • Had to cut hole near inlet damper for cables 90

Backup-Power Challenges l l Background Backup power is required for Essential loads (Equipment Systems & Emergency Systems) but not for all electrical loads Recent prolonged outages (blackouts, hurricanes, floods) have raised the importance of backing up what used to be thought of as non-essential loads Why? Hospitals cannot perform normal activities when those “non-essential” loads are not operational Periodic connection of load bank may be necessary to achieve sufficient generator loading (meet NFPA 99 guidelines for exhaust gas temperature) Case Studies Techniques Coordination ATSATS Designs Withstand PF PF andand X/RX/R Tips / Summary 91

Spare Critical Power Generator Gen 1 Utility B 1 Gen 2 Roll Up Spare B 2 Normal Bus Critical Bus S 1 S 2 “Non-Essential” Loads ATS 1 S 2 ATS 2 Critical Loads 92

Spare Critical Power Generator Gen 1 Utility B 1 Gen 2 Roll Up Spare B 2 Normal Bus Critical Bus S 1 S 2 “Non-Essential” Loads ATS 1 S 2 ATS 2 Critical Loads 93

Spare Critical Power Generator Gen 1 Utility B 1 Gen 2 Roll Up Spare How do I connect the generator to the switchgear? Normal Bus B 2 Critical Bus S 1 S 2 “Non-Essential” Loads ATS 1 S 2 ATS 2 Critical Loads 94

It Takes A While…. To connect from here… … to here … you must first bend conduit, break walls, pull and terminate cables… 95

Generator Quick Connect Switchboard Characteristics l Engineered Assembly designed for safe & fast connection of a mobile generator l Based on Cutler-Hammer Pow-R-Line switchboard construction l Indoor or Outdoor Enclosure l Generator Service disconnect circuit breaker rated up to 4000 amps l Cam-type plugs commonly found on mobile generator cables l Standard mechanical lugs provided for an alternative method of connecting generator cables 96

Spare Critical Power Generator Gen 1 Utility B 1 Gen 2 Roll Up Spare B 2 Normal Bus Critical Bus S 1 S 2 “Non-Essential” Loads ATS 1 S 2 ATS 2 Critical Loads 97

Spare Critical Power Generator Gen 1 Utility Roll Up Spare Gen 2 Multiple Hubbell 400 A Plugs B 1 1. Install Quick Connect Panel Quick Connect (QC) Panel B 2 Normal Bus Critical Bus S 1 S 2 “Non-Essential” Loads ATS 1 S 2 ATS 2 Critical Loads 98

Spare Critical Power Generator Gen 1 Utility 1. Install Quick Connect Panel Gen 2 2. Bring generator to site Quick Connect (QC) Panel B 1 B 2 Normal Bus Critical Bus S 1 S 2 “Non-Essential” Loads ATS 1 S 2 ATS 2 Critical Loads 99

Spare Critical Power Generator Gen 1 Utility 1. Install Quick Connect Panel Gen 2 2. Bring generator to site 3. Connect plug-in cables to generator 4. Connect other end of cables to QC panel Quick Connect (QC) Panel B 1 B 2 Normal Bus Critical Bus S 1 S 2 “Non-Essential” Loads ATS 1 S 2 ATS 2 Critical Loads 100

Spare Critical Power Generator Gen 1 Utility 1. Install Quick Connect Panel Gen 2 2. Bring generator to site 3. Connect plug-in cables to generator 4. Connect other end of cables to QC panel Quick Connect (QC) Panel B 1 B 2 5. Start generator 6. Close QC panel tie breaker QC tie breaker Normal Bus Critical Bus S 1 S 2 “Non-Essential” Loads ATS 1 S 2 ATS 2 Critical Loads 101

Quick Connect Panel 102

Would You Classify These Loads As Critical or Essential? l l l Kitchen and dietary department? Radiology and associated cooling? Computer network (hubs, routers, servers)? Computer room cooling for servers? Fan and exhaust loads for biohazard containment? Chillers, air handlers, BMS, dampers, AF drives for patient and occupant comfort? Article 702 Optional Standby Loads ? l Also consider n Rural versus city center – historical reliability 103

Roll Up Backup to Non-Essential Loads Gen 1 Utility B 1 Gen 2 Roll Up Spare B 2 Normal Bus Critical Bus S 1 S 2 “Non-Essential” Loads ATS 1 S 2 ATS 2 Critical Loads 104

Roll Up Backup to Non-Essential Loads Gen 1 Utility B 1 Gen 2 Roll Up Spare B 2 Normal Bus Critical Bus S 1 S 2 “Non-Essential” Loads ATS 1 S 2 ATS 2 Critical Loads 105

Roll Up Backup to Non-Essential Loads Gen 1 Utility Gen 2 K Roll Up Spare K B 1 B 2 Normal Bus Critical Bus S 1 S 2 “Non-Essential” Loads ATS 1 S 2 ATS 2 Critical Loads 106

Roll Up Backup to Non-Essential Loads Gen 1 Utility Gen 2 K Roll Up Spare K B 1 B 2 Normal Bus Critical Bus S 1 S 2 “Non-Essential” Loads ATS 1 S 2 ATS 2 Critical Loads 107

Roll Up Backup to Non-Essential Loads Gen 1 Utility Gen 2 Roll Up Spare Quick Connect (QC) Panel K K B 1 B 2 Normal Bus Critical Bus S 1 S 2 “Non-Essential” Loads ATS 1 S 2 ATS 2 Critical Loads 108

Roll Up Backup to Non-Essential Loads Gen 1 Utility Gen 2 Roll Up Spare Quick Connect (QC) Panel K B 1 K B 2 Normal Bus Critical Bus S 1 S 2 “Non-Essential” Loads ATS 1 S 2 ATS 2 Critical Loads 109

Roll Up Backup to Non-Essential Loads Gen 1 Utility Gen 2 Roll Up Spare Quick Connect (QC) Panel K B 1 K B 2 Normal Bus Critical Bus S 1 S 2 “Non-Essential” Loads ATS 1 S 2 ATS 2 Critical Loads 110

What Other Generator Problems Might Occur? l JCAHO allows operating generators at less than 30% load, but they state that these generators must be “exercised annually with supplemental loads of: n n n 25 percent of nameplate rating for 30 minutes, followed by 50 percent of nameplate rating for 30 minutes, followed by 75 percent of nameplate rating for 60 minutes for a total of two continuous hours. ” 111

“Supplemental Load” l l l One method is to connect a “load bank” to generators too boost load Load banks can be permanently mounted, but most sites just rent them from their engine dealer when needed Of course, rental units have to be connected to the hospital generator system safely: n “How do I connect a temporary load bank to my generator bank (without propping open a door or window to bring in cables and letting rodents, wasps, snakes etc, in? )” 112

Supplemental Load Gen 1 Utility Gen 2 Quick Connect (QC) Panel B 1 B 2 QC tie breaker Normal Bus Critical Bus S 1 S 2 “Non-Essential” Loads ATS 1 S 2 ATS 2 Critical Loads 113

Supplemental Load and Additional Generation Gen 1 Utility Gen 2 Quick Connect (QC) Panel B 1 B 2 Quick Connect (QC) Panel QC tie breaker Normal Bus Critical Bus S 1 S 2 “Non-Essential” Loads ATS 1 S 2 ATS 2 Critical Loads 114

Presentation Complete l l Questions? At conclusion of Q/A, those interested in CEU credit, we will next present a two question test. n n n Correct answer is either A, B, C or D Submit these answers with your information requested in the reminder e-mail sent to each person If you are interested in CEUs but did not get the answer and instruction sheet, send an email to me: Dave. GLoucks@eaton. com 115

Question 1 l Bus within switchboards built to the UL 891 standard must be built to withstand a short circuit current for what duration and still survive with no damage? A. 1 cycle (0. 01667 seconds) B. 3 cycle (0. 05 seconds) C. 4 cycle (0. 0667 seconds) D. 30 cycle (0. 5 second) 116

Question 2: What must be the ATS short-time rating? A. 3 cycles (0. 05 s) B. 6 cycles (0. 1 s) C. 12 cycles (0. 2 s) D. 24 cycles (0. 4 s) 117

Fax, E-mail, Submit on Web or Mail Answers l Include the other data requested (address, SS#, etc. ) on answer form l FAX: 412 -893 -2137 l Email: Dave. GLoucks@eaton. com l Web: www. pps 2. com/r 1 l Mail: Eaton Corporation 1000 Cherrington Parkway Moon Township, PA 15108 Att: Dave Loucks (412 -893 -3300) 118

CEU Credits l l You can review your credits on-line and print a transcript from https: //www. acenet. edu/transcripts/ Results are posted no later than 6 weeks after submittal of forms 119

The End Copy of Powerpoint presentation, webinar replay and FAQ will be posted to: www. pps 2. com/r 1/i. htm Questions: Dave. GLoucks@eaton. com © 2005 Eaton Corporation. All rights reserved.