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  • ABB Group January 4, 2015 | Slide 1

    MV Metal-Clad SwitchgearThe safest, most reliable Switchgear in the market today

    February 2008

  • ABB Group January 4, 2015 | Slide 2

    Arc-Resistant Standards

    Introduction Todays Topics

    What is Arc Flash and the risks it represents

    Arc-Resistant Switchgear Standards

    ABB Switchgear Offering

    Characteristics of SafeGear Arc-Resistant Switchgear

    Other Safety Features available in Switchgear today

  • ABB Group January 4, 2015 | Slide 3

    What is an Arc Flash?

    The result of a rapid release

    of energy due to an arcing fault

    between phases, neutral or a

    ground.

    An arc arises when at least part of the current passes through a

    dielectric, usually air

    Maximum peak power up to 40 MW

    Arc temperature up to five times the surface temperature of the sun

    (20,000C)

    Light intensity more than 2000 times

    that of normal office light

    Volumetric expansion approximately

    40,000+ - 1

    Temperature of

    the sun surface is

    about 5000C.

  • ABB Group January 4, 2015 | Slide 4

    Arcing Incidents Do Happen

    Fault characteristics

    An arc arises when at least part of the current

    passes through a dielectric, usually air

    Maximum peak power up to 40 MW

    Arc temperature up to five times the surface

    temperature of the sun (20 000C)

    Light intensity more than 2000 times that of

    normal office light

  • ABB Group January 4, 2015 | Slide 5

    Arc Flash Danger Statistics

    Currently, OSHA lumps Arc Flash incidents in with electrical incidents.

    A recent survey showed that 5-10 people per day go to burn centers due to arc flash incidents that does not include those going to local and regional hospitals

    That is 2000-3500 people a year in the US!

    With the high mortality rate of burn injuries, this can translate to hundreds of deaths a year

    IEEE did a study with a large utility and over the last 53 years, they have had 1 arc flash incident every 18 months.

  • ABB Group January 4, 2015 | Slide 6

    Arcing Incidents Do Happen

    Security Video of Arc flash incidentDistributed by NFPA

  • ABB Group January 4, 2015 | Slide 7

    Arc-Resistant Switchgear

    Causes of internal arc faults

    Improper maintenance, mechanical, and interlock

    failures

    Failure to follow procedures

    Gradual component or insulation breakdown

    Foreign objects, rodents, snakes, etc.

    Effects of an internal arc fault

    Pressure increase in an enclosed compartment

    Function of arc voltage, current, number, and duration of arcs, volume

    Rapid onset (10-15 ms) results in explosive forces

    Thermal effects, hot gases

    Catastrophic to nearby personnel and equipment

  • ABB Group January 4, 2015 | Slide 8

    Evolution of Arc-Resistant Standards

    Interest in Europe uninsulated bus was common

    Annex AA to IEC 298 was approved in 1981

    EEMAC G14-1 was published in 1987 in Canada

    Type A arc-resistant construction at the front only

    Type B arc-resistant construction at the front, back, and sides

    Type C arc-resistant construction at the front, back, and sides, and between compartments

    IEEE C37.20.7-2007 includes

    Type 1 similar to EEMAC Type A above

    Type 2 similar to EEMAC Type B above

    Annex A addresses suffixes B and C

    Type 1C Type 1, but also with arc-resistance designs or features between adjacent compartments

    Type 2B Type 2 with LV instrument compartment door open relay and maintenance personnel survive

    Type 2C Type 2 with arc-resistance features between adjacent compartments switchgear survives with minimum damage

    Type 2BC The ultimate in protection combines types 2B and 2C

  • ABB Group January 4, 2015 | Slide 9

    Industry Recognized Arc-Resistant Standards

    OSHA 29 Code of Federal Regulations (CFR) Part 1910, Subpart S

    NFPA 70E-2004, Standard for Electrical Safety in the Workplace

    IEEE 1584-2002, Guide for Arc Flash Hazard Analysis

    IEEE C37.20.7-2007, IEEE Guide for Testing Medium-Voltage Metal-Enclosed

    Switchgear for Internal Arcing Faults

  • ABB Group January 4, 2015 | Slide 10

    Arc-Resistant Standards

    Current Requirements and How They Apply

    OSHA 29 Code of Federal Regulations (CFR) Part 1910, Subpart S

    Safe practices to prevent electrical shock or burns must be

    implemented

    Mandates that exposed workers must be qualified

    Requires provisions for the appropriate personnel protective

    equipment (PPE)

    NFPA 70E-2004, Standard for Electrical Safety in the Workplace

    Details steps to comply with the OSHA requirements

    Worker training

    Appropriate, safe tools

    Safety program

    Arc flash hazard calculations

    PPE

    Equipment warning labels

  • ABB Group January 4, 2015 | Slide 11

    THE NEW NFPA 70E 2009, TABLE 130.7 (C) (9) Arc-Resistant SWITCHGEAR TYPE 1 OR 2

    Hazard/Risk Category for Arc-Resistant Switchgear

    Applies to clearing times of

  • ABB Group January 4, 2015 | Slide 12

    Arc Flash Introduction - Mitigation Techniques

    Redirecting energy away from workers

    Reducing the arcing current (En ~Ia)

    Not effective method as test data is required for current limiting devices (fuses)

    Increasing the working distance (E~1/D)

    Using remore racking device, remote operating devices incident energy might be reduced

    Reducing the clearing time (E~t)

    Zone selective interlocking

    slow (100ms) + breaker operate time)

    can not be used for retrofit installations

    Bus bar protection

    expensive to install due to number of CTs

    Light Detection

  • ABB Group January 4, 2015 | Slide 13

    ANSI C37.20.7 Accessibility Types

    1

    Front only

    1C

    Front plus between compartments within a section or between adjacent

    vertical sections (except main bus compartment)

    2

    Front, back, and sides

    2B

    Isolation of the Low Voltage Compartment with the instrument door open

    2C

    Front, back, and sides, plus between compartments within a section or

    between adjacent vertical sections (except main bus compartment)

    2BC

    Offers compartment to compartment and low voltage isolation. Offers the

    very best solution for personnel protection and system reliability.

    SafeGear meets IEEE C37.20.7-2007

    Type 2, 2B, 2C and 2BC!

  • ABB Group January 4, 2015 | Slide 14

    Arc Faults

    SafeGearConventional Switchgear

  • ABB Group January 4, 2015 | Slide 15

    Pressure Buildup

    0

    100

    200

    300

    400

    500

    600

    700

    800

    900

    1 3 5 7 9

    11

    13

    15

    17

    19

    21

    23

    25 time (ms)

    PS

    I

    enclosure

    rupture

    Pressure measurements

    vent flap

    opens

    Successful SafeGear test

    SafeGear

    conventional

  • ABB Group January 4, 2015 | Slide 16

    Introduction to ABB ANSI Switchgear

    5 to 15 kV metal clad switchgear

    Advance

    Traditional non-arc-resistant switchgear

    SafeGear

    Meets ANSI Standard C37.20.7-2007 for arc-resistance

    Four versions Types 2, 2B, 2C and 2BC available

    Vacuum circuit breakers

    AMVAC

    Magnetically actuated mechanism

    ADVAC

    Spring operated mechanism

  • ABB Group January 4, 2015 | Slide 17

    Ratings

    Nominal Voltage 4.16 7.2 13.8

    BIL (kV) 60 95 95

    Continuous Current (A) 1200 1200 1200

    Main Bus 2000 2000 2000

    3000 3000 3000

    Forced Air Cooled* 4000 4000 4000

    Short Circuit (kA) 20 20 20

    K Factor = 1.0 25 25 25

    31.5 31.5 31.5

    40 40 40

    50 50 50

    Ratings

    4000 A rating availab le for Advance only.

  • ABB Group January 4, 2015 | Slide 18

    ABB Metal-Clad Switchgear

    Features

    Galvanic construction

    Hem bending

    Modular design

    Bolted frame

    Instrument compartment

    Breaker compartment

    Bus and cable compartment

    Potential transformer compartment

    Arc-resistant switchgear

    SafeGear

    Power distribution center

    Plenum

    Circuit breaker technology

    ADVAC

    AMVAC magnetically actuated circuit breaker option

  • ABB Group January 4, 2015 | Slide 19

    Galvanic Construction

    Resistant to rust,

    corrosion and

    scratches

    No paint required

    Highly reflective

    (Side view with covers removed)

  • ABB Group January 4, 2015 | Slide 20

    Hem Bending

    No sharp edges for

    increased safety

    Improved rigidity

    Reduces arc propagation

    Forms a self-supporting

    structure

    Hem bending creates a rigid structure and sturdyconstruction in metal-clad switchgear (reinforced,

    arc-resistant door construction shown).

  • ABB Group January 4, 2015 | Slide 21

    Modular Design

    Bolted construction enables faster replacement and modification in the field

    Allows for easy replacements, repairs, and specialized configurations

    Maintains the smallest, compact product

  • ABB Group January 4, 2015 | Slide 22

    Instrument Compartment

    Total isolation from medium voltage components

    No instruments on breaker door

    Galvanic interiors provide supe

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