DNV Summarized

8/17/2019 DNV Summarized

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Section Keywords

Services

Essential Services

Important Services

Emergency services

Installation Short Circuit Proof Installation

IEC Zone

pen Dec!

"a#ardous $rea

Zone %Zone &

Zone '

Ca(le

conductor

core

wire

ca(le

Class ' Ca(le

Class ) ca(le

Emergency electric power supply

system


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Neutral Conductor

Voltage *evels

Safety Voltage

*ow voltage

"igh voltage

Switch(oard

+ain switch(oard

Switch(oard

Emergency switch(oard

Distri(ution (oard

$ssem(lies

Controlgear

Electrical components

Electrical e,uipment-

Semi.conductor assem(ly-

Switchgear

/rac!ing Inde0

1irst characteristic numeral

%

&

'

2

3)

4

Second characteristic numeral

%

&

'

2

Ingress

Protection of

Enclosures


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3

)

4

5

6


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DNV Electrical Installations

Definition

need to (e in continuous operation for maintaining the unit7s manoeuvra(ility in regard to propulsion and stee

e08 control9 monitoring and safety devices or systems for e,uipment for essential services

services that need not necessarily (e in continuous operation for maintaining for the unit7s manoeuvra(ility

(ut which are necessary for maintaining the unit7s functions8

e08 starting air and control air compressors

control9 monitoring and safety devices or systems for e,uipment to important services

services that are essential for safety in an emergency condition8

(are conductors mounted on isolating supports

dou(le insulated wires or conductors8

completely e0posed to the weather from a(ove or from at least one side8

source of ha#ard and or in which e0plosive gas and air mi0ture e0ists9 or may normally (e e0pected to (e pres

,uantities such as to re,uire special precautions for the construction and use of electrical e,uipment and ma

Control systems and au0iliary systems needed to (e in operation for the a(ove mentioned systems

or e,uipment are included in this term8

Zone '% dust8 Continuos ha#ardZone '& dust8 Intermittent ha#ard

Zone '' dust8 "a#ard under a(normal conditions

part of a construction or circuit designed for transmission of electric current

assem(ly consisting of a conductor and its own insulation

assem(ly consisting of one core where the insulation is at least flame retardant8

one or more cores

assem(ly protection

individual covering:s; :if any;common (raiding :if any;

protective covering:s; :if any;

inner and


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a conductor connected to the neutral point of a system

capa(le of contri(uting to the transmission of electric energy

rated voltage not e0ceeding )% V $C

ated voltages of more than )% V up to and inclusive & %%% V with rated fre,uencies of )% "# or 4% "#

direct.current systems where the ma0imum voltage does not e0ceed & )%% V

rated voltages of more than & !V and up to and inclusive &) !V

switch(oard directly supplied (y the main source of electrical power or power transformer

and intended to distri(ute electrical energy to the unit7s services8

not (eing directly supplied (y the main source of power will (e considered as main

switch(oards when this is found relevant from a system and operational point of view8

which in the event of failure of the main electrical power supply system9 is directly supplied (y the emergency

and

Protected against spraying water from a(ove up to 4%> from vertical


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Protected against splashing water

Protected against water =ets

Protected against heavy seas

Protected against the effects of immersion

Protected against su(mersion :water depth to (e given;


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?ey '%&38&%

Section

3%&

3%'

3%2

)%&

4%&

5%&

6%3

5%2

6%6


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6%@

6&&

@%&

@%'

@%2

&%%&

&%%'


9/15


10/15

?ated for ma08 temp

Important Service

System EarthingDisconnecting lin!s

3.wire system

$C Power

voltages up to and including )%% V $C

DC power-

"ull ?eturn Systems Shall (e used if-

')%V

A)%%VSteady state

/ransient state

$fter /ransient state

Emergency Distri(ution System

Voltage tolerance-

Voltage cyclic variation-

Voltage ripple

Environmental

Conditions

$m(ient temperature from 3) deg C to

2) deg C

/ype of Distri(ution

Systems

System Voltages and

1re,uency

Supply voltage

variations


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Voltage Drop $C Distri(ution

DC Distri(ution

Steady *oad Conditions

/ransient *oad Conditions

"armonic Distortion

Considerations when Designing

1i0ed Nominal

1re,uency


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E,uipment is not for use for emergency services

/emperature control is achieved (y at least two cooling units

/he e,uipment can (e started in a 3)BC am(ient temperature and !ept in operation until the lesser am(ient t

/he cooling e,uipment shall (e rated for a 3) deg C am(ient temperature

+alfunction of9 or loss of a cooling unit shall (e alarmed at a manned control station

if less than 3) deg C9 electrical ca(les for their entire length are ade,uately rated for the ma0imum am(ient t

E,uipment used for cooling and maintaining the lesser am(ient temperature is an important service9

$ny earthing impedances shall (e connected to the hull

$ny circulating currents in the earth connections do not interfere with control e,uipment circuits

If the system neutral is connected to earth9 suita(le disconnecting lin!s or terminals shall (e fitted9 for maint

In any four wire distri(ution system the system neutral shall (e connected to earth at all times without the us

three.phase three.wire with high.resistance earthed neutral

three.phase three.wire with low.resistance earthed neutral

three.phase three.wire with directly earthed neutral

three.phase three.wire with insulated neutral8

three.phase four.wire with neutral earthed9 (ut without hull return

single.phase two.wire with insulated neutral

single.phase two.wire with one phase earthed at the power source9 (ut without hull return8

two.wire insulated

two.wire with one pole earthed at the power source :without hull return;

single.wire with hull return

*imited and locally earthed systems

insulation level monitoring devices provided the circulation current does not e0ceed 2% m$ under the most un

intrinsically safe circuits8

DC power9 one of the (us(ars of the distri(ution (oard shall (e connected to the hull8

utgoing final su( circuits i8e8 all circuits fitted after the last protective device shall (e with insulated two.wire

Space "eaters in accommodation spaces9 soc!et outlets9 control9 instrumentation e,uipment

Phase voltage of a system with neutral earthed may (e used for this purpose8

control voltage to e0ternal e,uipment shall not e0ceed )%% V'8) of nominal $C system voltage

from &) to '% of nominal $C voltage8−

the voltage in a main distri(ution $C system shall not differ from nominal system voltage (y more than 2 w

/he voltage shall not differ from nominal system voltage (y more than 3 within ) s8

.&) to 2% of nominal DC system voltage

ma08 )

ma08 &%8


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/he re,uirement for ma0imum transient voltage is not applica(le to failure conditions8

Does not e0ceed 4 of system nominal voltage

Does not e0ceed &% of system nominal voltage

@) to &%) of rated fre,uency

@% to &&% of rated fre,uency

total voltage harmonic distortion shall not e0ceed 6

No single order harmonic shall e0ceed )8

additional heat losses in coils of switchgear and controlgear

resonance effects in the networ!

functioning of instruments and control systems su(=ected to the distortion

distortion of the accuracy of measuring instruments and protective gear :relays;

interference of electronic e,uipment of all !inds


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&%'

&%2

&%3

&%)

'%'

'%2

'%3


15/15

'%)

'%4

'%5

DNV Summarized

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