Hardware Short Circuit Capacity
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CALCULATION OF CROSS SECTIONAL AREA OF HARDWARE WITH RESPECT TO SHORT CIRCUIT LEVEL ASSUMING ADIABATIC THERMODYNAMIC PROCESS Usama Ahmed Transmission Spec ialty Ref: [1] http://www.openelectrical.org/wiki/index.php?title=Adiabatic_Short_Circuit_Temperature_Rise Ref: [1] IEC 60364-5-54 and IEC 60949 I sc_1 50kA := Specified Short circuit Level I sc_2 50kA := Specified Short circuit Level t 1 1s := Specified Short circuit clearing time t 2 1s := Specified Short circuit clearing time ρ d 7.8 10 3 - g mm 3 := Density of Hardware Steel q c 3.8 10 3 - J mm 3 := Volumetric Heat Capcity of Hrdware Steel @ 20 deg C K β 202 := °C Reciprocal of Temperature Coefficent of Resistivity @ 0 deg C c p 0.460548 J g K := Specific Heat Capacity of Hardware Steel θ i 35 := °C Initial Temperature of Hardware Steel Δθ 365K := Permissible Temperature Rise θ f 400 := °C Final Temperature of Hardware Steel ρ 138 10 6 - ohm mm := Resistivity of Hardware Steel @ 20 deg C ρ r 96 10 6 - ohm mm := Resistivity of Hardware Steel Calulated Coefficent of Hardware Material Properties k 1 ρ d c p Δθ ρ r := Calulated Coefficent of Hardware Material Properties k 2 q c β 20 + ( ) ρ ln 1 θ f θ i - β θ i + + := S 1 I sc_1 t 1 k 1 := S 2 I sc_2 t 2 k 2 := S 1 427.833 mm 2 = Calculated Minimum Permissible Cross Sectional Area of Hardware S 2 662.35 mm 2 = Calculated Minimum Permissible Cross Sectional Area of Hardware J 1 I sc_1 S 1 := J 2 I sc_2 S 2 := J 1 116.868 amp mm 2 = J 2 75.489 amp mm 2 = Calulated Maximum Permissible Current Density of Hardware Calulated Maximum Permissible Current Density of Hardware
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Substation string hardware short circuit / power arc rating calculation assuming adiabatic thermodynamic heat flow
Transcript of Hardware Short Circuit Capacity
CALCULATION OF CROSS SECTIONAL AREA OF HARDWARE WITH RESPECT TO SHORT CIRCUIT LEVEL ASSUMINGADIABATIC THERMODYNAMIC PROCESSUsama AhmedTransmissi on SpecialtyRef: [1] http://www.openelectrical.org/wiki/index.php?title=Adiabatic_Short_Circuit_Temperature_RiseRef: [1] IEC 60364-5-54 and IEC 60949 Isc_150kA := Specified Short circuit Level Isc_250kA := Specified Short circuit Levelt11s := Specified Short circuit clearing time t21s := Specified Short circuit clearing timed7.8 103 -gmm3 := Density of Hardware Steel qc3.8 103 -Jmm3 := Volumetric Heat Capcity of Hrdware Steel @ 20 deg CK 202 := C Reciprocal of Temperature Coefficent of Resistivity @ 0 deg Ccp0.460548JgK := Specific Heat Capacity of Hardware Steeli35 := C Initial Temperature of Hardware Steel 365K := Permissible Temperature Risef400 := C Final Temperature of Hardware Steel 138 106 - ohm mm := Resistivity of Hardware Steel @ 20 deg Cr96 106 - ohm mm := Resistivity of Hardware SteelCalulated Coefficent of Hardware Material Propertiesk1dcp r:= Calulated Coefficent of Hardware Material Properties k2qc 20 + ( ) ln 1fi- i++ :=S1Isc_1t1k1:= S2Isc_2t2k2:=S1427.833 mm2 =Calculated Minimum Permissible Cross Sectional Areaof HardwareS2662.35 mm2 = Calculated Minimum Permissible Cross Sectional Areaof HardwareJ1Isc_1S1:=J2Isc_2S2:=J1116.868ampmm2 =J275.489ampmm2 =Calulated Maximum Permissible Current Densityof HardwareCalulated Maximum Permissible Current Densityof Hardware
