DCGuard current U V W Fault Micro grid U V W Micro grid U V W AFE AFE INU U V W Battery 1200kWh G1 2000kW G2 2000kW G3 2000kW G4 2000kW LLL = = AFE AFE DC/DC U V W LCL ~ = U V W LCL ~ = DC Grid 1 VACON® NXP DCGuard™ DCGuard1 DC+ = L DC- =L DCGuard2 = DC+ L DC- L = LCL ~ = DC Grid 2 INU U V W Micro grid U V W Micro grid U V W = ~ Filter = ~ Filter = ~ = ~ U V W U V W LCL ~ = = ~ Filter = ~ Filter Main propulsion FWD 2000kW Shore supply 2000kW Hotel load 200kW Example of hybrid system where VACON® NXP DCGuard™ ensures the required system selectivity Main propulsion AFT 2000kW Hotel load 200kW Shore supply 2500kW DC- link voltage on feeding side. Negligible voltage dip on feeding side. DC current in connection cables. Proscuprercetinvte fault 3 Legend 4. Energy discharge time. 1. Normal situation(No fault) Current dI/dt=V/L 2 4 Current is within DCGuard nominal current capacity. V=Feeding DC voltage L=Inductance in the circuit DCGuard 2. Fault current rise time. Typical time:100-150µs* trip level Current dI/dt=V/L 5. Total fault clearance time. 1 dI V=Feeding DC voltage L=Inductance in the circuit Typical time:200-300µs* * System dependent dt Typical time:100-150µs* 3. Current cut off time. 5 DCGuard performs a current cut off by forcing all IGBTs open when current reaches the tripping limit of Time the DCGuard. Time:<5µs DKDD.PFP.906.A4.02 © Copyright Danfoss Drives | 2019.02
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