contents fefe f vd
Post on 07-Aug-2018
220 Views
Preview:
TRANSCRIPT
-
8/20/2019 Contents Fefe f Vd
1/13
Contents
[hide]
1- Use of
formulae
2- Simplified
table
3- Examples
Use of formulae
Figure G27 below gives formulae commonl used to calculate voltage drop in a given circuit per
!ilometre of length "copper cable with #$%E insulation&'
(f)
(*) +he full load current in amps
$) $ength of the cable in !ilometres
,) ,esistance of the cable conductor in .!m
for copper
for aluminium
/ote) , is negligible above a c's'a' of 0 mm2
#) inductive reactance of a conductor in .!m
/ote) # is negligible for conductors of c's'a' less than 0 mm2' (n the absence of an other
information ta!e # as being eual to '4 .!m'
) phase angle between voltage and current in the circuit considered generall)ϕ
(ncandescent lighting) cos5 6 1
http://www.electrical-installation.org/enwiki/Calculation_of_voltage_drop_in_steady_load_conditionshttp://www.electrical-installation.org/enwiki/Calculation_of_voltage_drop_in_steady_load_conditions#Use_of_formulaehttp://www.electrical-installation.org/enwiki/Calculation_of_voltage_drop_in_steady_load_conditions#Use_of_formulaehttp://www.electrical-installation.org/enwiki/Calculation_of_voltage_drop_in_steady_load_conditions#Simplified_tablehttp://www.electrical-installation.org/enwiki/Calculation_of_voltage_drop_in_steady_load_conditions#Simplified_tablehttp://www.electrical-installation.org/enwiki/Calculation_of_voltage_drop_in_steady_load_conditions#Exampleshttp://www.electrical-installation.org/enwiki/Calculation_of_voltage_drop_in_steady_load_conditions#Use_of_formulaehttp://www.electrical-installation.org/enwiki/Calculation_of_voltage_drop_in_steady_load_conditions#Use_of_formulaehttp://www.electrical-installation.org/enwiki/Calculation_of_voltage_drop_in_steady_load_conditions#Simplified_tablehttp://www.electrical-installation.org/enwiki/Calculation_of_voltage_drop_in_steady_load_conditions#Simplified_tablehttp://www.electrical-installation.org/enwiki/Calculation_of_voltage_drop_in_steady_load_conditions#Exampleshttp://www.electrical-installation.org/enwiki/Calculation_of_voltage_drop_in_steady_load_conditions
-
8/20/2019 Contents Fefe f Vd
2/13
$ed lighting) cos 7 '8ϕ
9luorescent with electronic ballast) cos 7 '8ϕ
:otor power)
;t start-up) cos5 6 '30
(n normal service) cos5 6 '4
Un) phase-to-phase voltage
-
8/20/2019 Contents Fefe f Vd
3/13
=alculations ma be avoided b using Figure G2 which gives with an adeuate approximation
the phase-to-phase voltage drop per !m of cable per ampere in terms of)
>inds of circuit use) motor circuits with cos5close to '4 or lighting with a cos5close to 1'
+pe of circuit? single-phase or 3-phase
x (* x $
> is given b the table
(* is the full-load current in amps
$ is the length of cable in !m'
+he column motor power @cos5 6 '30A of Figure G2 ma be used to compute the voltage drop
occurring during the start-up period of a motor "see example no' 1 after the Figure G2&'
c!s!a! in mm2 Single"p#ase circuit $alanced t#ree"p#ase circuit
otor po&er 'ig#ting otor po&er
ormal service Start"up ormal service Start"up
Cu * cos + , -! cos + , -!./ cos + , 0 cos + , -! cos + , -!./
1'0 2B 1'C 3 2 8'B
2'0 1B'B C'B 14 12 0'D
B 8'1 B'1 11'2 4 3'C
C 1 C'1 2'8 D'0 0'3 2'0
1 1C 3'D 1'D B'0 3'2 1'0
-
8/20/2019 Contents Fefe f Vd
4/13
1C 20 2'3C 1'10 2'4 2'0 1
20 30 1'0 'D0 1'4 1'3 'C0
30 0 1'10 'C 1'28 1 '02
0 D '4C 'BD '80 'D0 'B1
D 12 'CB '3D 'CB '0C '32
80 10 'B4 '3 'BD 'B2 '2C
12 140 '38 '2C '3D '3B '23
10 2B '33 '2B '3 '28 '21
140 3 '28 '22 '2B '20 '18
2B B '2B '2 '18 '21 '1D
3 0 '21 '18 '10 '14 '1C
Fig. G28: Phase-to-phase voltage drop ΔU for a circuit, in volts per ampere per km
1amples
1ample 0 "see Fig! G23&
; three-phase 30 mm2 copper cable 0 metres long supplies a B < motor ta!ing)
-
8/20/2019 Contents Fefe f Vd
5/13
1 ; at a cos 5 6 '4 on normal permanent load
0 ; "0 (n& at a cos 5 6 '30 during start-up
+he voltage drop at the origin of the motor cable in normal circumstances "i'e' with the distribution
board of Figure G23 distributing a total of 1 ;& is 1 < phase-to-phase'
hat is the voltage drop at the motor terminals)
(n normal serviceF
Guring start-upF
Solution)
-
8/20/2019 Contents Fefe f Vd
6/13
General rules of electrical installation
design
Connection to the MV utility distribution
network
Connection to the LV utility distribution
network
MV and LV architecture selection guide for
buildings
LV Distribution
Protection against electric shocks and
electric fires
Sizing and protection of conductors
Conductor sizing and protection
Conductor sizing:
methodology and definition
Oercurrent !rotection
!rinci!les
Practical alues for a
!rotectie scheme
Location of !rotectie deices
Conductors in !arallel
Practical method for determining the
smallest allowable cross-sectional area of
circuit conductors
General method for cable
sizing
"ecommended sim!lified
a!!roach for cable sizing
#izing of busbar trunking
systems $busways%
Determination of voltage drop
Ma&imum oltage dro! limit
Calculation of voltage drop
in steady load conditions
Short-circuit current
#hort'circuit current at the
secondary terminals of a MV(LVdistribution transformer
http://www.electrical-installation.org/enwiki/General_rules_of_electrical_installation_designhttp://www.electrical-installation.org/enwiki/General_rules_of_electrical_installation_designhttp://www.electrical-installation.org/enwiki/Connection_to_the_MV_utility_distribution_networkhttp://www.electrical-installation.org/enwiki/Connection_to_the_MV_utility_distribution_networkhttp://www.electrical-installation.org/enwiki/Connection_to_the_LV_utility_distribution_networkhttp://www.electrical-installation.org/enwiki/Connection_to_the_LV_utility_distribution_networkhttp://www.electrical-installation.org/enwiki/MV_and_LV_architecture_selection_guide_for_buildingshttp://www.electrical-installation.org/enwiki/MV_and_LV_architecture_selection_guide_for_buildingshttp://www.electrical-installation.org/enwiki/LV_Distributionhttp://www.electrical-installation.org/enwiki/Protection_against_electric_shocks_and_electric_fireshttp://www.electrical-installation.org/enwiki/Protection_against_electric_shocks_and_electric_fireshttp://www.electrical-installation.org/enwiki/Sizing_and_protection_of_conductorshttp://www.electrical-installation.org/enwiki/Conductor_sizing_and_protectionhttp://www.electrical-installation.org/enwiki/Conductor_sizing:_methodology_and_definitionhttp://www.electrical-installation.org/enwiki/Conductor_sizing:_methodology_and_definitionhttp://www.electrical-installation.org/enwiki/Overcurrent_protection_principleshttp://www.electrical-installation.org/enwiki/Overcurrent_protection_principleshttp://www.electrical-installation.org/enwiki/Practical_values_for_a_protective_schemehttp://www.electrical-installation.org/enwiki/Practical_values_for_a_protective_schemehttp://www.electrical-installation.org/enwiki/Location_of_protective_deviceshttp://www.electrical-installation.org/enwiki/Conductors_in_parallelhttp://www.electrical-installation.org/enwiki/Practical_method_for_determining_the_smallest_allowable_cross-sectional_area_of_circuit_conductorshttp://www.electrical-installation.org/enwiki/Practical_method_for_determining_the_smallest_allowable_cross-sectional_area_of_circuit_conductorshttp://www.electrical-installation.org/enwiki/Practical_method_for_determining_the_smallest_allowable_cross-sectional_area_of_circuit_conductorshttp://www.electrical-installation.org/enwiki/General_method_for_cable_sizinghttp://www.electrical-installation.org/enwiki/General_method_for_cable_sizinghttp://www.electrical-installation.org/enwiki/Recommended_simplified_approach_for_cable_sizinghttp://www.electrical-installation.org/enwiki/Recommended_simplified_approach_for_cable_sizinghttp://www.electrical-installation.org/enwiki/Sizing_of_busbar_trunking_systems_(busways)http://www.electrical-installation.org/enwiki/Sizing_of_busbar_trunking_systems_(busways)http://www.electrical-installation.org/enwiki/Determination_of_voltage_drophttp://www.electrical-installation.org/enwiki/Maximum_voltage_drop_limithttp://www.electrical-installation.org/enwiki/Short-circuit_currenthttp://www.electrical-installation.org/enwiki/Short-circuit_current_at_the_secondary_terminals_of_a_MV/LV_distribution_transformerhttp://www.electrical-installation.org/enwiki/Short-circuit_current_at_the_secondary_terminals_of_a_MV/LV_distribution_transformerhttp://www.electrical-installation.org/enwiki/Short-circuit_current_at_the_secondary_terminals_of_a_MV/LV_distribution_transformerhttp://www.electrical-installation.org/enwiki/General_rules_of_electrical_installation_designhttp://www.electrical-installation.org/enwiki/General_rules_of_electrical_installation_designhttp://www.electrical-installation.org/enwiki/Connection_to_the_MV_utility_distribution_networkhttp://www.electrical-installation.org/enwiki/Connection_to_the_MV_utility_distribution_networkhttp://www.electrical-installation.org/enwiki/Connection_to_the_LV_utility_distribution_networkhttp://www.electrical-installation.org/enwiki/Connection_to_the_LV_utility_distribution_networkhttp://www.electrical-installation.org/enwiki/MV_and_LV_architecture_selection_guide_for_buildingshttp://www.electrical-installation.org/enwiki/MV_and_LV_architecture_selection_guide_for_buildingshttp://www.electrical-installation.org/enwiki/LV_Distributionhttp://www.electrical-installation.org/enwiki/Protection_against_electric_shocks_and_electric_fireshttp://www.electrical-installation.org/enwiki/Protection_against_electric_shocks_and_electric_fireshttp://www.electrical-installation.org/enwiki/Sizing_and_protection_of_conductorshttp://www.electrical-installation.org/enwiki/Conductor_sizing_and_protectionhttp://www.electrical-installation.org/enwiki/Conductor_sizing:_methodology_and_definitionhttp://www.electrical-installation.org/enwiki/Conductor_sizing:_methodology_and_definitionhttp://www.electrical-installation.org/enwiki/Overcurrent_protection_principleshttp://www.electrical-installation.org/enwiki/Overcurrent_protection_principleshttp://www.electrical-installation.org/enwiki/Practical_values_for_a_protective_schemehttp://www.electrical-installation.org/enwiki/Practical_values_for_a_protective_schemehttp://www.electrical-installation.org/enwiki/Location_of_protective_deviceshttp://www.electrical-installation.org/enwiki/Conductors_in_parallelhttp://www.electrical-installation.org/enwiki/Practical_method_for_determining_the_smallest_allowable_cross-sectional_area_of_circuit_conductorshttp://www.electrical-installation.org/enwiki/Practical_method_for_determining_the_smallest_allowable_cross-sectional_area_of_circuit_conductorshttp://www.electrical-installation.org/enwiki/Practical_method_for_determining_the_smallest_allowable_cross-sectional_area_of_circuit_conductorshttp://www.electrical-installation.org/enwiki/General_method_for_cable_sizinghttp://www.electrical-installation.org/enwiki/General_method_for_cable_sizinghttp://www.electrical-installation.org/enwiki/Recommended_simplified_approach_for_cable_sizinghttp://www.electrical-installation.org/enwiki/Recommended_simplified_approach_for_cable_sizinghttp://www.electrical-installation.org/enwiki/Sizing_of_busbar_trunking_systems_(busways)http://www.electrical-installation.org/enwiki/Sizing_of_busbar_trunking_systems_(busways)http://www.electrical-installation.org/enwiki/Determination_of_voltage_drophttp://www.electrical-installation.org/enwiki/Maximum_voltage_drop_limithttp://www.electrical-installation.org/enwiki/Short-circuit_currenthttp://www.electrical-installation.org/enwiki/Short-circuit_current_at_the_secondary_terminals_of_a_MV/LV_distribution_transformerhttp://www.electrical-installation.org/enwiki/Short-circuit_current_at_the_secondary_terminals_of_a_MV/LV_distribution_transformerhttp://www.electrical-installation.org/enwiki/Short-circuit_current_at_the_secondary_terminals_of_a_MV/LV_distribution_transformer
-
8/20/2019 Contents Fefe f Vd
7/13
)'!hase short'circuit current
$*sc% at any !oint within a LV
installation
*sc at the receiing end of a
feeder as a function of the *sc at its
sending end
#hort'circuit current su!!lied
by a generator or an inerter
Particular cases of short-circuit
current
Calculation of minimum leels
of short'circuit current
Verification of the withstand
ca!abilities of cables under short'circuit
conditions
Protective earthing conductor (PE)
Connection and choice for
!rotectie earthing conductor
#izing of !rotectie earthing
conductor
Protectie conductor between
MV(LV transformer and the main
general distribution board $MGD+%
,-ui!otential conductor
he neutral conductor
#izing the neutral conductor
Protection of the neutral
conductor
+reaking of the neutral
conductor
*solation of the neutral
conductor
!or"ed e#ample of cable calculation
LV switchgear: functions and selection
Oeroltage !rotection
,nergy ,fficiency in electrical distribution
Power .actor Correction
Power harmonics management
http://www.electrical-installation.org/enwiki/3-phase_short-circuit_current_(Isc)_at_any_point_within_a_LV_installationhttp://www.electrical-installation.org/enwiki/3-phase_short-circuit_current_(Isc)_at_any_point_within_a_LV_installationhttp://www.electrical-installation.org/enwiki/3-phase_short-circuit_current_(Isc)_at_any_point_within_a_LV_installationhttp://www.electrical-installation.org/enwiki/Isc_at_the_receiving_end_of_a_feeder_as_a_function_of_the_Isc_at_its_sending_endhttp://www.electrical-installation.org/enwiki/Isc_at_the_receiving_end_of_a_feeder_as_a_function_of_the_Isc_at_its_sending_endhttp://www.electrical-installation.org/enwiki/Isc_at_the_receiving_end_of_a_feeder_as_a_function_of_the_Isc_at_its_sending_endhttp://www.electrical-installation.org/enwiki/Short-circuit_current_supplied_by_a_generator_or_an_inverterhttp://www.electrical-installation.org/enwiki/Short-circuit_current_supplied_by_a_generator_or_an_inverterhttp://www.electrical-installation.org/enwiki/Particular_cases_of_short-circuit_currenthttp://www.electrical-installation.org/enwiki/Particular_cases_of_short-circuit_currenthttp://www.electrical-installation.org/enwiki/Calculation_of_minimum_levels_of_short-circuit_currenthttp://www.electrical-installation.org/enwiki/Calculation_of_minimum_levels_of_short-circuit_currenthttp://www.electrical-installation.org/enwiki/Verification_of_the_withstand_capabilities_of_cables_under_short-circuit_conditionshttp://www.electrical-installation.org/enwiki/Verification_of_the_withstand_capabilities_of_cables_under_short-circuit_conditionshttp://www.electrical-installation.org/enwiki/Verification_of_the_withstand_capabilities_of_cables_under_short-circuit_conditionshttp://www.electrical-installation.org/enwiki/Protective_earthing_conductor_(PE)http://www.electrical-installation.org/enwiki/Connection_and_choice_for_protective_earthing_conductorhttp://www.electrical-installation.org/enwiki/Connection_and_choice_for_protective_earthing_conductorhttp://www.electrical-installation.org/enwiki/Sizing_of_protective_earthing_conductorhttp://www.electrical-installation.org/enwiki/Sizing_of_protective_earthing_conductorhttp://www.electrical-installation.org/enwiki/Protective_conductor_between_MV/LV_transformer_and_the_main_general_distribution_board_(MGDB)http://www.electrical-installation.org/enwiki/Protective_conductor_between_MV/LV_transformer_and_the_main_general_distribution_board_(MGDB)http://www.electrical-installation.org/enwiki/Protective_conductor_between_MV/LV_transformer_and_the_main_general_distribution_board_(MGDB)http://www.electrical-installation.org/enwiki/Equipotential_conductorhttp://www.electrical-installation.org/enwiki/The_neutral_conductorhttp://www.electrical-installation.org/enwiki/Sizing_the_neutral_conductorhttp://www.electrical-installation.org/enwiki/Protection_of_the_neutral_conductorhttp://www.electrical-installation.org/enwiki/Protection_of_the_neutral_conductorhttp://www.electrical-installation.org/enwiki/Breaking_of_the_neutral_conductorhttp://www.electrical-installation.org/enwiki/Breaking_of_the_neutral_conductorhttp://www.electrical-installation.org/enwiki/Isolation_of_the_neutral_conductorhttp://www.electrical-installation.org/enwiki/Isolation_of_the_neutral_conductorhttp://www.electrical-installation.org/enwiki/Worked_example_of_cable_calculationhttp://www.electrical-installation.org/enwiki/LV_switchgear:_functions_and_selectionhttp://www.electrical-installation.org/enwiki/Overvoltage_protectionhttp://www.electrical-installation.org/enwiki/Energy_Efficiency_in_electrical_distributionhttp://www.electrical-installation.org/enwiki/Power_Factor_Correctionhttp://www.electrical-installation.org/enwiki/Power_harmonics_managementhttp://www.electrical-installation.org/enwiki/3-phase_short-circuit_current_(Isc)_at_any_point_within_a_LV_installationhttp://www.electrical-installation.org/enwiki/3-phase_short-circuit_current_(Isc)_at_any_point_within_a_LV_installationhttp://www.electrical-installation.org/enwiki/3-phase_short-circuit_current_(Isc)_at_any_point_within_a_LV_installationhttp://www.electrical-installation.org/enwiki/Isc_at_the_receiving_end_of_a_feeder_as_a_function_of_the_Isc_at_its_sending_endhttp://www.electrical-installation.org/enwiki/Isc_at_the_receiving_end_of_a_feeder_as_a_function_of_the_Isc_at_its_sending_endhttp://www.electrical-installation.org/enwiki/Isc_at_the_receiving_end_of_a_feeder_as_a_function_of_the_Isc_at_its_sending_endhttp://www.electrical-installation.org/enwiki/Short-circuit_current_supplied_by_a_generator_or_an_inverterhttp://www.electrical-installation.org/enwiki/Short-circuit_current_supplied_by_a_generator_or_an_inverterhttp://www.electrical-installation.org/enwiki/Particular_cases_of_short-circuit_currenthttp://www.electrical-installation.org/enwiki/Particular_cases_of_short-circuit_currenthttp://www.electrical-installation.org/enwiki/Calculation_of_minimum_levels_of_short-circuit_currenthttp://www.electrical-installation.org/enwiki/Calculation_of_minimum_levels_of_short-circuit_currenthttp://www.electrical-installation.org/enwiki/Verification_of_the_withstand_capabilities_of_cables_under_short-circuit_conditionshttp://www.electrical-installation.org/enwiki/Verification_of_the_withstand_capabilities_of_cables_under_short-circuit_conditionshttp://www.electrical-installation.org/enwiki/Verification_of_the_withstand_capabilities_of_cables_under_short-circuit_conditionshttp://www.electrical-installation.org/enwiki/Protective_earthing_conductor_(PE)http://www.electrical-installation.org/enwiki/Connection_and_choice_for_protective_earthing_conductorhttp://www.electrical-installation.org/enwiki/Connection_and_choice_for_protective_earthing_conductorhttp://www.electrical-installation.org/enwiki/Sizing_of_protective_earthing_conductorhttp://www.electrical-installation.org/enwiki/Sizing_of_protective_earthing_conductorhttp://www.electrical-installation.org/enwiki/Protective_conductor_between_MV/LV_transformer_and_the_main_general_distribution_board_(MGDB)http://www.electrical-installation.org/enwiki/Protective_conductor_between_MV/LV_transformer_and_the_main_general_distribution_board_(MGDB)http://www.electrical-installation.org/enwiki/Protective_conductor_between_MV/LV_transformer_and_the_main_general_distribution_board_(MGDB)http://www.electrical-installation.org/enwiki/Equipotential_conductorhttp://www.electrical-installation.org/enwiki/The_neutral_conductorhttp://www.electrical-installation.org/enwiki/Sizing_the_neutral_conductorhttp://www.electrical-installation.org/enwiki/Protection_of_the_neutral_conductorhttp://www.electrical-installation.org/enwiki/Protection_of_the_neutral_conductorhttp://www.electrical-installation.org/enwiki/Breaking_of_the_neutral_conductorhttp://www.electrical-installation.org/enwiki/Breaking_of_the_neutral_conductorhttp://www.electrical-installation.org/enwiki/Isolation_of_the_neutral_conductorhttp://www.electrical-installation.org/enwiki/Isolation_of_the_neutral_conductorhttp://www.electrical-installation.org/enwiki/Worked_example_of_cable_calculationhttp://www.electrical-installation.org/enwiki/LV_switchgear:_functions_and_selectionhttp://www.electrical-installation.org/enwiki/Overvoltage_protectionhttp://www.electrical-installation.org/enwiki/Energy_Efficiency_in_electrical_distributionhttp://www.electrical-installation.org/enwiki/Power_Factor_Correctionhttp://www.electrical-installation.org/enwiki/Power_harmonics_management
-
8/20/2019 Contents Fefe f Vd
8/13
Characteristics of !articular sources and
loads
PhotoVoltaic $PV% installation
"esidential and other s!ecial locations
,lectroMagnetic Com!atibility $,MC%
Contents
[hide]
1 - Use of
formulae
2 - Simplified
table
3 - Examples
Use of formulae
Figure G27 below gives formulae commonl used to calculate voltage drop in a given circuit per
!ilometre of length "copper cable with #$%E insulation&'
(f)
(*) +he full load current in amps
$) $ength of the cable in !ilometres
,) ,esistance of the cable conductor in .!m
for copper
for aluminium
/ote) , is negligible above a c's'a' of 0 mm2
http://www.electrical-installation.org/enwiki/Characteristics_of_particular_sources_and_loadshttp://www.electrical-installation.org/enwiki/Characteristics_of_particular_sources_and_loadshttp://www.electrical-installation.org/enwiki/PhotoVoltaic_(PV)_installationhttp://www.electrical-installation.org/enwiki/Residential_and_other_special_locationshttp://www.electrical-installation.org/enwiki/ElectroMagnetic_Compatibility_(EMC)http://www.electrical-installation.org/enwiki/Calculation_of_voltage_drop_in_steady_load_conditionshttp://www.electrical-installation.org/enwiki/Calculation_of_voltage_drop_in_steady_load_conditions#Use_of_formulaehttp://www.electrical-installation.org/enwiki/Calculation_of_voltage_drop_in_steady_load_conditions#Use_of_formulaehttp://www.electrical-installation.org/enwiki/Calculation_of_voltage_drop_in_steady_load_conditions#Simplified_tablehttp://www.electrical-installation.org/enwiki/Calculation_of_voltage_drop_in_steady_load_conditions#Simplified_tablehttp://www.electrical-installation.org/enwiki/Calculation_of_voltage_drop_in_steady_load_conditions#Exampleshttp://www.electrical-installation.org/enwiki/Characteristics_of_particular_sources_and_loadshttp://www.electrical-installation.org/enwiki/Characteristics_of_particular_sources_and_loadshttp://www.electrical-installation.org/enwiki/PhotoVoltaic_(PV)_installationhttp://www.electrical-installation.org/enwiki/Residential_and_other_special_locationshttp://www.electrical-installation.org/enwiki/ElectroMagnetic_Compatibility_(EMC)http://www.electrical-installation.org/enwiki/Calculation_of_voltage_drop_in_steady_load_conditionshttp://www.electrical-installation.org/enwiki/Calculation_of_voltage_drop_in_steady_load_conditions#Use_of_formulaehttp://www.electrical-installation.org/enwiki/Calculation_of_voltage_drop_in_steady_load_conditions#Use_of_formulaehttp://www.electrical-installation.org/enwiki/Calculation_of_voltage_drop_in_steady_load_conditions#Simplified_tablehttp://www.electrical-installation.org/enwiki/Calculation_of_voltage_drop_in_steady_load_conditions#Simplified_tablehttp://www.electrical-installation.org/enwiki/Calculation_of_voltage_drop_in_steady_load_conditions#Examples
-
8/20/2019 Contents Fefe f Vd
9/13
#) inductive reactance of a conductor in .!m
/ote) # is negligible for conductors of c's'a' less than 0 mm2' (n the absence of an other
information ta!e # as being eual to '4 .!m'
) phase angle between voltage and current in the circuit considered generall)ϕ
(ncandescent lighting) cos5 6 1
$ed lighting) cos 7 '8ϕ
9luorescent with electronic ballast) cos 7 '8ϕ
:otor power)
;t start-up) cos5 6 '30
(n normal service) cos5 6 '4
Un) phase-to-phase voltage
-
8/20/2019 Contents Fefe f Vd
10/13
*alanced 3-phase) 3 phases "with or without neutral&
Fig. G27: Voltage-drop formulae
Simplified table
=alculations ma be avoided b using Figure G2 which gives with an adeuate approximation
the phase-to-phase voltage drop per !m of cable per ampere in terms of)
>inds of circuit use) motor circuits with cos5close to '4 or lighting with a cos5close to 1'
+pe of circuit? single-phase or 3-phase
x (* x $
> is given b the table
(* is the full-load current in amps
$ is the length of cable in !m'
+he column motor power @cos5 6 '30A of Figure G2 ma be used to compute the voltage drop
occurring during the start-up period of a motor "see example no' 1 after the Figure G2&'
c!s!a! in mm2 Single"p#ase circuit $alanced t#ree"p#ase circuit
otor po&er 'ig#ting otor po&er
ormal service Start"up ormal service Start"up
Cu * cos + , -! cos + , -!./ cos + , 0 cos + , -! cos + , -!./
1'0 2B 1'C 3 2 8'B
-
8/20/2019 Contents Fefe f Vd
11/13
2'0 1B'B C'B 14 12 0'D
B 8'1 B'1 11'2 4 3'C
C 1 C'1 2'8 D'0 0'3 2'0
1 1C 3'D 1'D B'0 3'2 1'0
1C 20 2'3C 1'10 2'4 2'0 1
20 30 1'0 'D0 1'4 1'3 'C0
30 0 1'10 'C 1'28 1 '02
0 D '4C 'BD '80 'D0 'B1
D 12 'CB '3D 'CB '0C '32
80 10 'B4 '3 'BD 'B2 '2C
12 140 '38 '2C '3D '3B '23
10 2B '33 '2B '3 '28 '21
140 3 '28 '22 '2B '20 '18
2B B '2B '2 '18 '21 '1D
3 0 '21 '18 '10 '14 '1C
-
8/20/2019 Contents Fefe f Vd
12/13
Fig. G29: Example 1
1ample 2 "see Fig! G.-&
; 3-phase B-wire copper line of D mm2 c's'a' and a length of 0 m passes a current of 10 ;' +he
line supplies among other loads 3 single-phase lighting circuits each of 2'0 mm2 c's'a' copper 2 m
long and each passing 2 ;'
(t is assumed that the currents in the D mm2 line are balanced and that the three lighting circuits are
all connected to it at the same point'
hat is the voltage drop at the end of the lighting circuitsF
Solution)
-
8/20/2019 Contents Fefe f Vd
13/13
Figure G2 shows '00
top related