Backup Power Automatic Transfer NIPSCO Energy … · Backup Power Automatic Transfer NIPSCO Energy ... the desired phase angle different and ... the load to/from the power sources

© 2007 Eaton Corporation. All rights reserved.

Backup Power Applications/Considerations

Backup Power Types

Automatic Transfer Switch Basics

Backup Power Automatic Transfer

NIPSCO Energy Symposium symposium

Presenters McGill Power - Jeremy Irmeger

Eaton - Barry Graves

Objective & Agenda

Objective

• Understanding the basics of how to

identify and properly apply UPS’s

Uninterruptible Power Supplies) and

ATS’ (Automatic Transfer Switches) for

accommoding for seamless systems .

Agenda

• What is a UPS

• UPS Types

• What is a Automatic Transfer Switch

• Transfer Switch Types

• Transfer Switch Application Categories

• Transition Types

• Basic Components of a Transfer Switch

• Application Considerations

• Questions

Bypass Isolation Magnum Front Access

Interruption Sag Swell

Undervoltage Line Noise

Switching Transients Frequency Variation Harmonic Distortion

Overvoltage

The 9 Common Power Problems

3 (+1) Basic Types of UPS

(

Standby

• “Off Line”

Line

Interactive

On Line

• “Double

Conversion”

Powerware Series 3 The Series 3 (Stand-By) UPS delivers

power protection from 3 of the most

common power problems that threaten

your equipment and data

Powerware Series 5 The Series 5 (Line-Interactive) UPS

delivers power protection from 5 of the

most common power problems that

threaten your equipment and data

Powerware Series 9 The Series 9 (On-Line) UPS delivers

power protection from all 9 of the most

common power problems that

threaten your equipment and data

Interruption

Sag

Swell

Under-

voltage

Over-

voltage

Switching

transients

Frequency

variation

Harmonic

distortion

Line

noise

Normal Operation

Power Failure Event

Buck/Boost

Ferroresonant

• “+1”

Powerware Series Ferro The Series Ferro UPS delivers

galvanic isolated power protection from

8 of the most common power problems

that threaten equipment and data

System Input

UPS Power

Module

Battery Cabinet

What is a UPS System?

System Output

To PDU N.O.

AC AC

DC

Maintenance Bypass Panel

1. Double Conversion

2. Online System

How Much Downtime is Acceptable?

Power Availability Equivalent Power Disruptions (yr)

99.9%

99.99%

99.999%

99.9999999%

8.8 hours

0.88 hours

5.3 minutes

< 3 seconds

ISPs,

e-Business,

Communications,

Electronics mfg.

N+ Redundancy

Food Processing

Server Operating Systems

Generators and Some UPS

Hospitals, Airports

Generator Only

Residential Homes

Typical Grid Power

Automatic Transfer Switch

UTILITY LOAD GENERATOR

A device which transfers electrical loads between two

sources of power by using either manual or automatic

controls.

UTILITY UTILITY

Bypass Isolation Transfer Switch

• An automatic transfer switch with an additional bypass isolation switch

• Provides ability to perform maintenance of the main transfer switch power device, without interruption of power to the load

• Applied in high reliability applications:

• Provides emergency power to life safety and other critical loads

Transfer Switch Types

• There are only two ways to transfer power:

• Automatic

• If loads are very critical, an automatic transfer switch would

probably be used insure the fastest possible transfer.

• Non-Automatic (manual, or electrically operated)

• If loads are not quite as critical, but still cannot go for any

extended period of time without power, a Non-Automatic or manual transfer switch could be used.

Non-automatic vs Manual Transfer

• Electrically operated non-automatic transfer

switches. The switch electrically transfers power when a

pushbutton, usually mounted on the switch’s enclosure, is pushed.

If necessary, the switch can also be manually operated.

• Manually initiated, Electrically operated

• Manually operated transfer switches provide all the

mechanics to effect the transfer from source to source. The actual

transfer of power, however, is by true hand operation of the

transfer switch.

• Manually initiated, Manually operated

National Electric Code

Application

Category

NFPA 70

• NFPA 70 - National Electric

Code

• Article 700 - Emergency

Systems

• Article 701 - Legally

Required Standby Systems

• Article 702 - Optional

Standby Systems

• Article 708 - COPS

• Article 517 - Health Care

Facilities

• NFPA 99 - Health Care Facilities

• NFPA 110 - Emergency &

Standby Systems

• NFPA 20 - Fire Pumps

• NFPA 70E – Workplace Safety

Application examples

include emergency

call centers

ATS labeled for use

on emergency

systems.

No requirement for

transfer time.

Transfer equipment

separate from other

emergency, legally

required, or optional

loads.

Must include

provisions for roll-up

generator if using

one generator.

Article 708 COPS

Application examples

include any system

where a power

interruption would

create life safety or

health hazards.

Must automatically

transfer in 10

seconds

Shall be listed for

emergency use (UL

1008 only).

Shall supply only

emergency loads.

Article 700 Emergency Systems

Application examples

include any system

where a power

interruption would

create hazards or

hamper rescue or fire

fighting operations.

Must automatically

transfer in 60

seconds

Shall be listed for

emergency use (UL

1008 only).

Article 701 Legally Required

Application examples

include any system

where a power

interruption would

cause discomfort or

disrupt a process.

Automatic/manual

transfer. No transfer

time requirement.

Allows for option as

such as:

• Go to neutral

position

• Auto/Manual

Selector switch

Article 702 Optional Systems

© 2007 Eaton Corporation. All rights reserved.

Transfer Switch Transition Types

Open Transition

• Also called a “break-before-make” switch. One set of contacts opens

before the other set closes

• There is a definite break in power as the load is taken off one source

and connected to another.

• This is the most common and least expensive

Normal

Emergency

Loads

TS N

TS E

Delayed Transition

• Break Both Sides – Delayed Transition

• One set of contacts opens before the other

• The other set of contacts delays in closing

• Load is disconnected from power during all transfers

Normal

Emergency

Loads

TS N

TS E

Delayed Transition

• Time delay neutral

• Requires a 3 position mechanism

• Timed delay in the neutral position, typically 0-120sec

• 3 sec is typically a good starting point

• Load Voltage Decay

• Senses back emf voltage

• Will pause in neutral position until regenerative voltages are at

10-30%

• On Eaton transfer switches option 32 cannot be

reprogrammed in the field. A new controller must be

purchased.

32a

32b

100 m/secs

overlap-time

Normal

Emergency

Loads

TS N

TS E

Closed Transition

Closed Transition

• Closed Transition is also called a “make-before-break” switch.

• There is no interruption in power to a critical load when using this

type of switch.

• Both power sources are connected to the load before the break

occurs.

• Parallels the loads for < 100ms

• The two power sources have to have the same voltage and

frequency and be synchronized for the switch to transfer.

• Permits the periodic testing of an emergency source, such as a

generator, without interrupting power to the loads

Consideration for selecting Transition Types

• When transferring two live sources, abnormal motor inrush current

can occur leading to possible damage of motor windings, insulation,

couplings and in some cases, the load itself.

• Inrush currents are caused by the motor’s residual voltage being out

of phase with the voltage source to which it’s being transferred.

• Methods of control are:

• Open Inphase transfer

• Motor load disconnect control circuit

• Delayed transition - Time Delay Neutral, Load Voltage Decay

• Closed transition – less than 100 ms paralleling of sources

Open In-phase Transfer

• Feature that allows a live transfer between two sources only when

the phase difference between the two is near to zero.

• This feature prevents in-rush currents from exceeding normal starting

currents in the case where motor loads are being transferred

• How it works:

• Monitor samples the relative phase angle between the two sources being

transferred

• When the two sources are within the desired phase angle different and

are approaching zero phase angle difference, the inphase monitor

signals the transfer switch to operate.

• The operating time of the transfer switch is key in utilizing an inphase

monitor (must transfer in less than ten cycles)

• In-phase monitor and VFD’s do not work well together, use TDN.

In-phase doesn’t give the VFD’s time to reset.

32f

Motor Load Disconnect Control Circuit

• Selected motor loads are de-energized

during transfer operation

• Controller signals contact to open

approx. 3 seconds prior to transfer,

thus de-energizing selected loads.

• Loads are turned onto the generator

after a designated time delay.

• Loads can be turned on at one time or

sequentially so as to not block load the

generator.

• Motor load disconnect works well

when the generator is sized at the min.

45

© 2007 Eaton Corporation. All rights reserved.

Automatic Transfer Switches - Main Components

Transfer Switch Main Components

An automatic transfer switch (ATS) is made up of several main

components

Controller –

• Continually monitors the condition of the power sources

• Initiates start command to backup generator,

• Initiates transfer and retransfer to good power source

Power switching device

• Power device rated to transfer the load to/from the power sources

Control Power Transformer panel

• Supplies operational power to the switching device/controller

Main Components - Controller

In an ATS, the controller is basically the “brains”

of the ATS, that contains all the logic/intelligence

to initiate the switching. The controller performs

following functions:

• Senses the source voltage and frequency

• Sends a start command to the back up

power if the main source is lost.

Commercial ATC-300+

Controller

Main Components – Switching Device

The switching device is the main power device that transfers the load

from one power source to another. The switching device includes the

main power device and the transfer mechanism. The ATS controller

tells the switching device when to make the transfer/retransfer to a

good source

Two basic types of switching devices:

• Contactor

• Specifically designed contactors to perform load transfer between

to AC sources. Transfer switches do not use motor starting/lighting

type contactors.

• Molded Case/Power Case Switch

• A molded case or power case circuit breaker without and /or with a

trip unit. Used when a circuit requires a compact, high capacity

disconnect device.

Main Components – Contactor Switching Device

Contactor based

• The contactor switching device includes the main power assembly and

the operating mechanism.

• The power assembly is composed of the individual power poles.

• The operating mechanism includes the solenoid and the mechanical

interlock.

Power Assembly

Operating Mechanism

3 Pole Contactor

Moving

Contact Source 1

Bus

Source 2

Bus

Load Bus

Single Power Pole

Main Components – Molded Case or Power Case Circuit Breaker Switching Device

Molded Case or Power Case Circuit Breaker Based

• The molded case/power case circuit breaker switching device is a circuit

breaker without and/or with the overcurrent trip. The switching device is

composed of two separate power devices. One device is for closing on source

1 and the other for closing on source 2. The operating mechanism includes

the motor operator.

Motor

Operating

Mechanism

3 Pole Molded Case Switch

Power Assembly 3 Pole Power Case Switch

Power Assembly

Source 1

Device

Source 2

Device

Motor

Operator in

Power Case

Switch

Main Components – Transformer Panel

Control Power

• Provided by small Control Power Transformers –CPT- connected to the

normal and the emergency source. The good source then provides the control power needed for the ATS to properly operate.

• Provided with a multi tap primary allowing the CPT to be used on different

voltage applications permitting a simple field change from one voltage to

another.

Basic Information for ATS Selection

When selecting a Transfer Switch, review the following:

– Types of load to be transferred

– Transition type

– Open In phase, Delayed, Closed Transition

– Application Type

– Life Safety, Emergency, Optional

– Switch Ratings

– Voltage rating, Phase, # poles

– Continuous Current rating/amps

– Overload and fault current withstand ratings

– Configuration Type

– Service Entrance

– Bypass Isolation

UPS and ATS Basics

Questions?