Capacitor Test Bed / CERN |
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Vdcpk | 5500V |
Vacpkpk | 4000V |
Vtotpk | 7500V |
Responsibles: |
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This composite voltage is meant to supply a load constituted by a set of capacitors.
The capacitance value changes depending upon the test to be effectuated, with a maximum rms current fixed in 80Arms.
Power converter architecture
The AC source:
The AC source is the most demanding in term of power. In-fact it has to provide all the kVAr needed by the tested capacitors.
The worst conditions are met when the testing of the fully sized element is required. To keep a limit, let’s consider the present capacitor value of 2mF; the following calculations give us the power needed:
Pac3ph | 500kVA |
Vacgrid | 400V |
Vpll | 400Vrms(line2line) |
Ip | 720Arms |
Vsll | 1850Vrms |
Is | 160Arms |
The DC source:
The simplest DC source is a 3 phase diode bridge. For easier realization (and to keep compatibility with other testing requirements), a 12 pulse diode bridge is foreseen.
Two 6 pulses diode rectifiers are then connected in series.
The following values have to be considered for bridge sizing:
Udc= | 100/2800V |
Vsll | 2000Vrms (line2line) |
Is | 10Arms |
As | 34kVA |
Vpll | 400Vrms |
Ip | 100Arms |
Ap | 68kVA |
Control overview simplified schematic