High Voltage Safety Course Handout CD 1

WELCOME TO IMTC HIGH VOLTAGE SAFETY PROGRAM Please Fill in The Registration Forms SAFETY HAS PRIORITY OVER SERVICE CONTINUITY AND ECONOMICS

IEEE - IEC PROVE DEAD THE PLACE OF WORK

High Voltage System Safety Requirement High Voltage system training is now part of STCW code 2010 ( Manila Amendment ) as mentioned on section B- III /2 The convention is in force till - 2013 The convention covers the responsibility for operating and maintaining the High Voltage ( above 1000 volts) electrical power plants on board ships and process plate forms

MODULE STRUCTURE
THE ROUTINE / TIMINGS
PRE & POST COURSE ASSESSMENT
LAYOUT AND GENERAL SAFETY IN THE PREMISES AND THE high voltage ELECTRICAL LAB
DURATION OF THE COURSE
ATTENDANCE
BRIEF ABOUT IMTC
IMTC COMPLIMANTRY BUS

SAFETY IS MORE ABOUT ATTITUDE THAN APPTITUDE GENERAL ACTIVITIES ONBOARD • • • • •

Inspection Operation Maintenance Repair Replacement

BEFORE CARRYING OUT ANY ONE OF THE ABOVEACTIVITIES MAKE SURE: 1. 2. 3. 4. 5.

What is to be done. If required make notes Where. Location. Environment. Elements How. Procedures. Caution. Warning. Risk assessment (Permits) When. Precedent Why.

MODULE : 1

SCOPE:The program is intended for:• Electrical Personnel maintaining, operating and repairing Electrical apparatus • Non Electrical Personnel operating electrical equipment • Engineers • Watch keepers • Those responsible for safe control and management of high voltage power systems in a marine environment

This training includes: • The functional operational and safety requirement for a Marine High Voltage system • Maintain and repair of High Voltage switch gear • Taking appropriate action when dealing with faults in a High Voltage system • Switching strategies for isolating components of High Voltage system • Using suitable apparatus for isolation and testing of High Voltage equipment • Switching and isolation procedures on a Marine High Voltage system • Understanding safety documents for High Voltage systems • Testing of Insulation Resistance (IR) and Polarization Index (P/I) on High Voltage equipment

COURSE OBJECTIVES ON COMPLETION OF THE COURSE THE PARTICIPANTS WILL HAVE SUFFICIENT KNOWLEDGE AND ENABLE THEM TO UNDERSTAND :


Voltage, Voltage levels and High Voltage




Advantages of high voltage




Risks and hazards associated with High Voltage




Familiarize with High Voltage Switch Gear




High Voltage safety, precaution and procedures during maintenance and operations




Understand and demonstrate the functional, operational and safety requirements for a Marine High Voltage system




Assist suitably qualified personnel to carry out the inspection, operation, maintenance and limited repairs on High Voltage apparatus




Safely take necessary remedial action during system faults




Devise a switching strategy for isolating HV system / Apparatus in accordance with specified safety procedures documented and a thorough risk assessment




Select suitable apparatus for isolation and testing HV equipment




Perform 5k V insulation resistance (IR) and Polarization Index ( P I ) on High Voltage equipment




High voltage switch gear construction, operation and safety features




Protection systems and applications




Work permits and company specific High Voltage Safety related documents




Trapped key system for sequential isolation and procedures to “PROVE DEAD” the place of work




Table top Exercises

General Personal safety includes 1 Follow Safety policies: Every company has its own safety policy as per the rules of SOLAS (ISM code). Understand and follow these points but also put them in practice

2 Situational Awareness: Know your surroundings and working environment and the risk involved and tackle the problems

3 Knowhow and Training: Correct operating knowledge of different equipment tools and systems on board, including safety procedures and emergency plans through proper training

4 Use of PPE: Every person on board ships must know what PPE is to be used and when and donning and checking. Maintain your PPE so as it is fit for use all the time as and when required

5 Help Yourself First: When you and your colleagues are trapped in dangerous situation, help your self first to get out of the situation and then help others

6 Know Your Ship Inside - Out: On joining a ship be familiar and know every nook and corner of the ship including location of fire fighting appliances, life saving appliances, alarms , escape routes, life boats and every thing needed in an emergency

7 Know Your Emergency Duties: Every crew member should know his emergency duties

8 Avoid Panic Attacks: It is human to get tensed or nervous in case of an accident. Try to control emotions to maintain mental peace and to act in a quick and smart manner under the pressure of an emergency situation

High Voltage Safety

Isolation and access for Maintenance

DIE Disconnect – Isolate – Earth PROCEDURES • No Electrical conductors should be regarded as being safe unless it has been isolated earthed, secured and proved dead • Precautions should be taken to ensure that isolated equipment can not be re energized. Lock out …. Tag out. Put up Warning and Caution notices • Voltage indicators should always to be tested before and after use • When not attended the barriers should be placed around live conductors • If isolation is done by other than competent person then it should be demonstrated to the competent person

Electricity can kill • More than 3000 non fatal electric shock accidents are reported every year in USA,1000 in UK • About 1000 people die every year from electrocution and surprisingly voltage was < 600 volts • Be careful about Ice berg syndrome in case of Electrical injuries / burns

SAFETY PRECAUTIONS

INTRODUCTIONThe management of Marine High Voltage Power Plant • High voltage safety rules and procedures • Electrical hazardous and precautions a) Electric shock (touch potential) b) Arcs/sparks and blast c) Earthing d) Operation and safety features • Legislative background 1. International Health and safety legislation 2. Flag state health and safety legislation 3. ESR (Electrical Safety Rules). Company specific 4. Code of Safe Working Practices (CSWP) 5. Health and Safety Executive (HSE)

MODULE :- 2 Brief revision of Power system on board

ELECTRICAL POWER SYSTEM
The generator ( Alternator ) - Source of power. (Converts mechanical energy into Electrical energy by Electro Magnetic Induction)
Brief on power and power factor
Advantages of high voltage over low voltage

AC / DC

SERIES OR PARALLEL

POWER AND POWER FACTOR ACTIVE POWER = V x I x Cos. phai = KW REACTIVE POWER = V x I x sine phai = KVAR APPARENT POWER = V x I = KVA POWER FACTOR = KW / KVA

• Impedance ( Z ) of the load decides the Power demand • Resistive component of the impedance decides Active power. kW ( Governor )? • Inductive component of the impedance decides the Reactive power. kVAR (AVR )?

INTRODUCTION The Management of Health and Safety at Work, regulation : Risk Assessment. Every employer (Senior personnel, Manager, Superintendent) shall make a suitable and sufficient assessment of :1. Risk to the health and safety of his employees (subordinates) to which they are exposed whilst they are at work: and 2. In making or reviewing the assessment the employer shall take particular account of ; a) The experience, lack of awareness of risk and immaturity of New joiners, Trainees and Apprentices b) The fitting – out and lay out of the work place c) The nature, degree and duration of exposure to physical biological, chemical agents and radiation ( very high Voltage) d) The form, range and the use of the work equipment and the way it is handled

Contd. e) f)

The organization of process and activities The extent of health and safety training provided to young and new employees (Operators, Maintainers and Trainees)

Capabilities of training:1. 2. a)

Every employer (Senior authorized/ Authorized person ) shall, in entrusting tasks to his employee ( Competent person) take into account their capabilities as regards health and safety Every employer shall ensure that his employees are provided with adequate health and safety training:On their being recruited into the undertaking and on their being exposed to new or increased risk because of :(Transfer, introduction of new work equipment, introduction of new technology and introduction of new system of work, modification etc.)

• THE TRAINING REFERED ABOVE SHALL :a) Be repeated periodically where applicable b) Be adapted to take account of any new or changed risk to the health and safety of the employees concerned c) Take place during working hours

General Safety Principles and Prevention 1. 2. 3. 4. 5. 6.

7. 8.

Avoiding risk Evaluate the risk which can not be avoided Combating the risk at source Adapting to technical progress Replacing dangerous by non dangerous or by less dangerous Developing a coherent overall prevention policy which covers technology, organization of work , working conditions, social relationships and influence of factors relating to the working environment Giving collective protection measure priority over individual protective measures Giving appropriate instructions to employees (subordinates)

Management of high voltage on board ships / platforms • Arrangement of high voltage switch rooms Switch rooms Equipment Switch Boards Transformers Protection Relays • Tripping and auxiliary supplies (110 / 220 dc source) • Earthing • Key safe / trapped key system • Fault levels • Application of protection system • Prove dead the place of work. Switching schedule • Documentation

ENERGY TRANSMISSION Energy can be transmitted by various means:
Mechanically
Hydraulically


Electrically
By Radiation and other means Electricity is the most common “energy transmission” mean ADVANTAGES OF ELECTRICAL MEANS:
Most efficient
Pollution free
Flexible
Instant availability over any distance
Comparatively less maintenance
Low weight to high power ratio for a given capacity

VOLTAGE AND VOLTAGE LEVELS VOLTAGE & LEVELS





Low Voltage : Medium Voltage : High Voltage : Extra High Voltage

Up to 1000 volts 1000 to 6600 volts 6600 to 11000 volts Above 11000 volts


NOTE : ON BOARD ANY VOLTAGE ABOVE 1000 VOLTS IS BE TREATED AS HIGH VOLTAGE • Above voltage figures are in RMS • The peak value of the voltages would be above figures divided by 0.707

• Illustration: • 1000 volts RMS = 1414 volts peak & • 6600 volts RMS = 9335 volts peak • 9000 volts RMS = ? volts peak

MODULE :- 3 SAFETY BOOK / MANUAL

AN OVERVIEW

THE SAFETY MANUAL / BOOK & IT’S PURPOSE Safety has priority over service continuity, equipment damage or economics (IEEE )
Provide safety principles to be used for protecting individuals from potential injuries and even death caused by electrical hazards.
The basic safety program is for supervisors, managers, electricians, engineers and the designers / specifiers of equipment used in electrical systems
The purpose of the safety book is to increase the safety awareness issues faced by the individuals who work on or near electrical equipment as well the system operators and equipment designers / specifiers Safety guide lines are recommended by various international and national safety organizations like: OSHA

: Occupational Safety and Health Administration(USA)

IEC

: International Electro technical Commission (UNO)

ANSI

: American National Standards Institute (USA)

EAW

: Electricity At Work (United Kingdom ) (Regulation 1989)

ELECTRICAL SAFETY RULES – AN OVERVIEW Rules, scope, responsibilities, authorities, familiarization, objections

See: 1) ESR 1(company specific) 2) Code of safe working practice for merchant Seamen

Integrity

Modifications, adjustments, approvals, records, maintenance

See: 1) ESR 1(company specific)

3

Access

Rooms, locks, duties

See: 1) ESR 1 (Company specific rules)

4

Work

Electrical distribution, operating positions, permits, planning, risk assessment, preparation, completion, testing

See: 1) ESR 1( company specific) 2) Safety Management System (SMS) 3) Hazardous Area Guide

5

Competence

Competence assessment training

See: 1) ESR 1 2) ESR 3

1

Responsibilities Authorization

2

and

HIGH VOLTAGE SAFETY RULES OBJECTIVES- Govern all works undertaken on high voltage system include; • Duties • Variations / amendments • Issue • Approval / sanctions DEFNITIONS• Approved- Of type and method sanctioned in writing • Live /dead – Electrically charged • Isolated – Disconnected from all sources of power • High voltage – Any voltage in access of 1000 volts

• • • • • • • • • • • • •

High voltage apparatus Electrical engineer Senior authorized person Authorized person Competent person Permit to work Sanction to test Limitation of access Caution/Danger notice Circuit main Earth Additional Earth/Earthed Key safe Safety lock

ARRANGEMENTS FOR SAFE WORKING
Personal protective equipment (PPE)
Guarding (when working in the proximity of live electrical equipment)
Use of safety locks, key exchange and lock out boxes
Risk assessment “ Matrix” HSE.( HEALTH AND SAFETY EXECUTIVE)
Documentation ( permits should be ” in writing “ and not verbal, on telephones or walkie talkies)

EMERGENCY CONDITIONS’ When does an emergency condition arise? How would you define an emergency condition? Fire, flood, gas leak, trapped person, etc. • First preference should be the safety of personnel • Immediate steps to be taken to remove the danger and inform the people/person • Do not enter an area which is prohibited to you • Switch off the power supply.

This may not be possible in certain circumstances NOTE; THINK AND BE AWARE OF THE EFFECTS CAUSED BY ANY ACTION TAKEN

MODULE - 4 •

Advantages of High voltage system

•

Risks and hazards associated with high voltage

ADVANTAGES OF HIGH VOLTAGE (3.3/ 4.4 / 6.6 / 11K.v. etc. • TRANSMISSION OF POWER TO LONG DISTANCES • FOR A GIVEN ENERGY LEVEL THE ARC INTENSITY IS LOW (The current is low hence I x I x t is low) • LOW WEIGHT / POWER RATIO. ( COMPACT SYSTEM ) • LOW / NO MAINTENANCE ON METAL ENCLOSED SWITCH GEAR

RISKS / HAZARDS ASSOCIATED WITH HIGH VOLTAGE

Note :- PROPERLY USED ELECTRICITY IS NOT DANGEROUS • FOLLOW THE RULES AND REGULATIONS FOR SAFE WORKING (WARNING AND CAUTION) • OUT OF CONTROL ELECTRICITY CAN CAUSE HARM TO HUMANS, THE EQUIPMENT AND THE ENVIORNMENT • HEATING EFFECTS ( ARCS AND SPARKS )CAN ALSO CAUSE FIRES AND BURNS EVEN WITHOUT CONTACT

RISKS / HAZARDS ASSOCIATED WITH HIGH VOLTAGE Hazards can include : a) Poor work conditions, equipment and practices b) Careless and inadvertent actions on the part of the individuals Common electrical hazards that can cause injury and even death


Electric shock with touch potential (current is the boss)




Arc-flash burns ( from contact, short circuits ) and radiant's (Tissue damage ).Temperatures reaching up to 37,000*C




Arc blast impact from expanding air and vaporized material (vaporized copper expands 67,000 times in volume )




Obnoxious / toxic gases




Formation of HCl from burning PVC insulation on the cables

A high voltage electric shock will almost certainly lead to severe injury or fatality Factors that could increase the risk of receiving an electric shock; • • • • • •

High Voltage work carried out close to a person who is not familiar with High Voltage hazards High Voltage insulation testing Equipment using water as part of High Voltage plant Using test instruments when taking High Voltage measurements High Voltage equipment stores energy even after disconnection If the High Voltage circuit main earth is removed while carrying out any maintenance

Ensure that necessary precautions / safety standards are being followed up during operations & maintenance. 1)Ensure proper electrical connection before charging any switchgear 2)Ensure that we are not leaving any tool within panel, electrical equipment 3) HT breakers – Do not charge without wearing 33KV hand gloves & without closing breaker panel 4) Do not touch pf capacitor terminals without discharging them 5) Ensure all electrical safety standards while

handing any electrical equipment

ELECTRIC SHOCK WITH “TOUCH POTENTIAL” • Muscles in human body are controlled electrically • Brain controls the muscles @ 10 pulses / second

• 60 Hz. Power with 120 pulses / sec is eminently suited to kill • Earth Leakage Circuit Breakers (ELCB,s) should trip in 200 milliseconds or less with a fault current of 30 mA • At 200 mA it would take approx. 400 milliseconds for the heart to stop

EFFECTS OF ELECTRIC CURRENT ON HUMAN BODY(TOUCH POTENTIAL) The severity of an Electric shock, can have dramatic effects and, depends upon the following key factors:
Current intensity and type- ac/dc
Contact duration
Tension (Voltage)
Body resistance. (Approx. 1500 Ohms)


Current ”path ways” through the body
“FREQUENCY” (Hz) of the shock current
Psychological condition of the recipient
Sex, age and general health of the recipient
Environment
Attire etc. (PPE)

EFFECTS OFELECTRIC CURRENT ON HUMAN BODY 0.9 – 1.2 mA

Current just perceptible

1.2 – 1.6 mA

Tickling sensation in the hand as from ants

1.6 – 2.2 mA

Sensation that the hand has gone to sleep

2.2 – 2.8 mA

Same sensation perceptible in the wrist also

2.8 – 3.5 mA

Slight stiffening of the hand

3.4 – 4.5 mA

Considerable stiffening of the hand, the lower arm growing tired

4.0 – 5.0 mA

Feeling of cramps and slight trembling in the hands

4.5 – 5.0 mA

Cramp in the lower arm

5.0 – 7.0 mA

Slight cramp in the upper arm ( unpleasant )

6.0 mA

WOMEN CAN JUST BREAK THIS CONTACT (LET GO)

9.0 mA

MEN CAN JUST BREAK THIS CONTACT

15 – 20 mA

REALEASE IMPOSSIBLE CAN NOT BE TOLERATED

20 – 40 mA

Serious and very painful contractions of the muscles, breathing stops, but normally resumes if current is interrupted within

5 seconds

50 – 100 mA

VENTRICULAR- FIBRILLATION. HEART MUSCLES UNABLE TO RELAX thus pumping stops leading to death

AT HIGH VOLTAGES

The recipient can be thrown off and may survive but with severe burns

AT LOW VOLTAGE

Death can occur at relatively low currents, but

time is important

Importance of Earthing

A rough relationship between the shock current measured in milliamps and time measured in milliseconds, that can be tolerated by a normal healthy person CURRENT = 116 / root TIME Roughly, thus a 50 mA current for 4 seconds would not be very dangerous. Calculate the approx. current that would flow through a human body with 1500 Ohm,s resistance from a touch potential of 230 volts

MODULE – 5

High Voltage systems General Lay out of High Voltage Switch Board Comparison between 440volts and 6600 volts

TABLE OF COMPARISON BETWEEN 6.6 kV AND 440V 6.6 k V high voltage

440 volts

CURRENT(FOR A GIVEN CAPACITY)

LOW

HIGH

TYPE OF CIRCUIT BREAKER

VCB,SF6,OIL,Air Blast

ACB

ACB/VCB MAINTENANCE

VACUUM CHECKER/GAP

VISUAL CHECK

SAFETY DEVICE LOCATION

SEPARATE PROTECTION

INCLUDED INSIDE ACB

CONTROL CIRCUIT VOLTAGE

DC 110V

DC 24 V

BUS BAR

SMALL

LARGE

BUS BAR DISTANCE

WIDER

NARROW

MSB PROTECTION

SEGREGATED COMPARTMENTS

WITHOUT COMPARTMENTS

UNDER SHORT CIRCUIT

EXPLOSION

NO EXPLOSION

PROTECTION AGAINST SHORT CIRCUIT

PRESSURE RELIEF FLAPS AND REINFORCED DOORS

NO PRESSURE RELIEF FLAPS

CIRCUIT BREAKER CONNECTOR

WITH AUTOMATIC SAFETY SHUTTERS

NO SAFETY SHUTTERS

EARTHING DEVICE

WITH EARTHING SWITCH

NO EARTHING SWITCH

MSB DOORS

MECHANICAL INTERLOCK SYSTEM

NO NEED

Diesel Generator Panel

MODULE - 6 High voltage switch gear

STANDARDS AND GUIDE LINES RELATED TO SAFETY Key organizations , agencies and commissions throughout the world associated with the safety are:
IEEE

Institute of Electrical and Electronics Engineers (USA)


NFPA

National Fire Protection Agency (USA)


OSHA

Occupational Safety & Health Organization (USA)


BIS

Bureau Of Indian Standards ( INDIA)


IEC

International Electro-technical Commission (Standards - UNO)


CENELEC European Committee For Electro-technical Standards (EU) IEEE 1584 guide for flash/ arc” hazard calculations”:

Incident energy < 1.5 calories / cm2 will cause a burn just curable The guide lines from NFPA- 70 provide guidance on appropriate level of Personal Protective Equipment (PPE) as follows

ARCS / SPARKS / BLASTS
Arcs can also take place due to breakdown of air gaps
Due to a high voltage across the gap a flash over between phases or phase to earth causing a very large fault currents. (CORONA)
Partial Discharge ( P D ). Premature failure of insulation
The arc temperature can be as high as 20,000* C. This may cause severe burns, loss / temporary loss of vision. The effects may be dramatic
A” blast” may follow the power arc and lead to vaporization of the material involved ( contacts

, bus bars and steel panels etc.)


In case of copper the metal expands 67,000 times in volume when vaporized, leading to an explosion
An explosion is a very fast expansion of surrounding air and objects can be knocked out from fixtures and fittings and hurled about with very high force
Since the fault energy is calculated as ( i2t,), limiting the current will limit the amount of the fault energy by use of proper/certified protective devices

TYPICAL INCIDENT ENERGY LEVELS AND RISK CATEGORIES
The table is based on the calculations to IEEE 1584 for a typical LNG carrier with two 2.5 MW turbine and two 1.25 MW Diesel generator sets connected to an insulated distribution system at 440 volts 60 hz.
The distances are measured to the arc source and the figures shown on the table refer to the open doors and covers
Table clearly shows that the arc flash energy is much higher close to the source of the power generation
Long length of cables, right capacity fuses / fast acting MCCBs help reduce the risk when working on panels and starters remote from the main switch board
PPE ( gloves, goggles / glasses and full sleeve boiler suits should be used for all the live work. Face shields with hood should be used where the incident energy is 5 cal/cm2 and above

TYPICAL INCIDENT ENERGY LEVELS AND RISK CATEGORIES Scenario

Fault current

Fault Clearing Time

Arc Safe Distance

Incidence Energy at 455 mm

Risk Category

Main Switchboard* One Turbine Generator connected

20 kA

0.5 sec

3375 mm

24 cal / cm2

4

Cargo switchboard.*Two Turbine and one Diesel Generator connected to Main Switch Board

5.8 kA

0.2 sec

850 mm

3.1 cal / cm2

1

Machinery Space vent fan starter. Two turbine Generators connected to Main Switch board

20 kA

0.2 SEC.

1811 mm

9.6 cal / cm2

3

Machinery space vent fan starter. One Diesel Generator connected to Main Switch board

10 kA

0.2 sec.

1186 mm

5.15 cal / cm2

2

63 kW motor ( supplied via 30m of 3 core 25mm2 )

8 kA

0.2 sec

457 mm

1.26 cal / cm2

0

STANDARDS NFPA 70 E (TABLE FROM NFPA 70) (PPE) Wearing PPE increases the level of incident energy that can be endured without injury PPE basically is to provide a barrier between the arc and the naked skin. Note: From a practical viewpoint , over reliance on PPE is counterproductive PPE is restricting and may not permit the wearer to work effectively

Risk Energy level Category Cal / cm2

PPE

0