AN-639What are the connections for 3-phase 4-wire wye service (with three voltage sensors)?RACFANTIALIASINGIABFILTERRIBANRBVRVAPCTPHASEACTSOURCEPHASEBRBPHASECRACFANTIALIASINGIBPRBFILTERIBNVRVBPCTLOADRACFRBRBVRVCPRANTIALIASINGICPFFILTERVICNNCFFigure 6. 4-Wire Wye Service Connections with Three Voltage Sensors
ActivePower=(VAP−VN)×(IAP−IAN)+(VBP−VN)×(IBP−IBN)+(VCP−VN)×(ICP−ICN)=(VA×IA)+(VB×IB)+(VC×IC
)To select this calculation mode in the ADE7754, the WATMOD register should be 00x00 and WATSEL = 0x00 according to the ADE7754 Data Sheet.
What are the connections for 3-phase 4-wire wye service (with two voltage sensors)?RACFANTIALIASINGIAPFILTERRIBANRBVRVAPCTCTPHASEASOURCEPHASEBRBPHASECANTIALIASINGIBPFILTERIBNCTRACFRLOADBRBVRVCPRANTIALIASINGICPFFILTERVICNNCFFigure 7. 4-Wire Wye Connections with Two Voltage Sensors
ActivePower=(VAP−VN)×((IAP−IAN)−(IBP−IBN))+(VCP−VN)×((ICP−ICN)−(IBP−IBN))=VA×(IA−IB)+VC×(IC−IB
)To select this calculation mode in the ADE7754, the WATMOD register should be 0x01 and WATTSEL = 0x07.
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AN-639What are the connections of the analog inputs in 3-phase 3-wire delta service?For 3-phase 3-wire systems, only two voltage inputs are connected to the ADE7754. One phase is used as a refer-ence (connected to VN of the ADE7754) and the other two phases are referred to this phase. In 3-phase 3-wire connection, you cannot get VAB and IC directly. For mea-suring IC, you need an additional CT. For VAB, the ADE7754 actually measures VBC and VAC. VAB can be calculated from these two values assuming a constant
What are the connections for 3-phase 4-wire delta service?RARBRFVRVAPCTCFANTIALIASINGFILTERIAPIANANTIALIASINGFILTERICPICNphase difference between the three phases (120Њ). To select this calculation mode in the ADE7754, the WATTMOD register should be 0x00 and WATTASEL = 0x3, 0x5, or 0x6.
RACFANTIALIASINGIAPFILTERRIBANRBVRVAPCTPHASEALOADSOURCEPHASECRFVNPHASEBCFCTRACFRBRBVRVBPANTIALIASINGIBPFILTERIBNFigure 8. 3-Wire Delta Connections
ActivePower=(VAP−VN)×(IAP−IAN)+(VBP−VN)×(IBP−IN)=(VA−VB)×IA+(VB−VC)×IB
REV. 0RFPHASEACTLOADSOURCEPHASECRACFPHASEBRFCTVRVCPRRFFVNCFANTIALIASINGIBPFILTERIBNFigure 9. 4-Wire Delta Connections
To select this calculation mode in the ADE7754, the WATTMOD register should be 0x02 and WATTSEL = 0x07.ActivePower=(VAP−VN)×((IAP−IAN)–(VBP−IBN))+(VCP−VN)×(ICP−IN)=VA×(IA–IB)+VC×IC
Is there a time delay between the zero crossing on analog inputs of the voltage channel and the falling of IRQ at 50 Hz?The zero-crossing detection has an inherent time delay from the low-pass fi lter. This time delay is approximately 0.6 ms as stated in the ADE7754 Data Sheet.
What is the error and dynamic range of the rms measurement (registers) in the ADE7754?The error on the rms measurement depends on the level and type of input (current or voltage). On the voltage side, we recommend synchronizing the Vrms reading with the zero crossing of this phase to reduce the ripple noise in the VRMS register. By doing that, you can get errors below 1% in the range of FS to FS/20 with offset correc-tion. On the current channel, the error can be below 1% in the range of FS to FS/100 with offset correction.
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