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（ABB技术应用白皮书4） circuit-breakers inside LV switchboards 2008.pdfOTCinterface
2 Advices to improve the current carrying capacity
Advicestoimprovethec
DB11T 1826-2021 森林消防综合应急救援队伍训练规范sideswitchboards
n its turn,the enclosure exchanges heat towards the external environment. Also this heat exchange occurs by conduction (through the cables connected to the
assembly),convection andradiation,asshownin Figure 7. In enclosures with a degree of protection not very high or with ventilation openings, part of the heat s exchanged througha realaircirculationbetweenthe assemblyandtheexternalenvironment. Fiaure7
2.1 Power loss inside switchboards
2.1.1 Internal structure
As an example to illustratethe influence of this pheno menon, Table 4 shows thepercentage value representing the part of losses developing inside the enclosure related to the power loss inside the conductor bars.
romthesedata.itresultsthattheincreaseoftherated currentand consequentlythenumberofbusbarsin Darallelperphaseandthematerialusedfortheseparation of the conductorbars may considerably affect heating.
Advicestoimprovethe
currents shall result into nullinduction; on the contrary. if each conductor is enclosed by a single ring (Figure 8a), the total induction is not null, with the consequent circulation of induced current,powerloss andtherefore heatgeneration
sideswitchboards
Technical Application Papers
ying capacity of the circuit
sideswitchboards
side switchboards
eakersinsideswitchboards
Pc = Pnc × (Ib / Incr)2
Pse = Pnse (Ib/lnsB)2 × 3 × LsB
efore, with reference to the typology, the length "L" and the load current of the busbars installed inside nboard, the contribution in terms of power loss of the single length and the total power loss are reporte 11below:
Cables As regards cables, taking reference to Table 8 above, the same method used for the busbars can be applied and therelevantresultsarereported inTable12
side switchboards
Then, the total power dissipated inside the switchboard is given by the sum of the three conti termined above, therefore:
2.1.4 Paths of the current
side switchboards
Technical Application Papers
2.2Dissipationof the heat generated
2.2.1 Switchboard ventilation
Kersinsideswitchboards
2.2.2 Side surfaces and positioning 0
switchboards
covered. The values of the parameter "b" related to the different surface tvpes are shown in Table 13.
2.2.3 Forms of internal separation of
switchboards
Table 14: For enclosures without ventilation openings and effecti oolingsurface>1.25m
r enclosures without ventilation openings and effective ooling surface>1.25m
15: For enclosures with ventilation openings and effective
Fromthetablesabove,itresultshowhorizontalpartitions can cause air temperature rises up to30% (3partitions without ventilation openings),
2.2.4 Switchboardprotection degree
2.3 Dissipation of the heat generated in the
sideswitchboards
blems linked to conved
breakersinsideLVswitd
Technical Application Papers
side switchboards
tofacilitatetheconnectionbetweentheverticalterminals andtheverticalconnectionbusbars,itispossibletouse bars suitablybent as shown inFigure 16.
too much the air flow and prevent it from reaching the upper terminals causing the loss of the benefits of cooling oyconvection
side switchboards
Technical Application Papers
side switchboards
2.3.2 Problems linked to conduction
side switchboards
insideswitchboards
FcErotflateteminals for
T4250 Fixed
insideswitchboards
T5400 Fixed
insideswitchboards
T6630 Fixed
T6630 Withdrawable
sideswitchboards
T6800 Withdrawable
nsideswitchboards
nsideswitchboards
NB/T 10393-2020 海上风电场工程施工安全技术规范7V1000 Withdrawable
nsideswitchboards
sideswitchboards
T7V1250 Withdrawable
nsideswitchboards
FZ/T 51008-2014 再生聚酯(PET)瓶片T7 S.H.L. 1600
sideswitchboards
10°℃ 20°℃ 30°℃ 40°℃ 50°℃ 60°℃C 70°C In [A] MIN MAX MIN MAX MIN MAX MIN MAX MIN MAX MIN MAX MIN MAX 20 19 27 18 24 16 23 14 20 12 17 10 15 8 13 32 26 43 24 39 22 36 19 32 16 27 14 24 11 21 50 37 62 35 58 33 54 30 50 27 46 25 42 22 39 80 59 98 55 92 52 86 48 80 44 74 40 66 32 58 100 83 118 80 113 74 106 70 100 66 95 59 85 49 75 125 103 145 100 140 94 134 88 125 80 115 73 105 63 95 160 130 185 124 176 118 168 112 160 106 150 100 104 90 130 200 162 230 155 220 147 210 140 200 133 190 122 175 107 160 250 200 285 193 275 183 262 175 250 168 240 160 230 150 220