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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