ADE7953 single phase connection for Dual live wire

Question

Hello 
 In Taiwan for single phase. we can connect L,N with ADE7953/ADE7854 as below. But in America, there are two phase (L1, L2, N) on single phase application. How to connect L1/L2/N to input VP/VN of ADE7953 for voltage and current measurement? Thank you.

BR 
 Patrick

dave.smith · Accepted Answer

there are a couple ways to do this 
 1. measure line to line voltage and current in each leg. after calibration power line 1 = voltage/2 * IA power line 2 = voltage/2 * IB

2. measure line to line voltage and use one ct to measure both line 1 and line 2 currents. The link below explains this method 
 https://www.analog.com/media/en/technical-documentation/application-notes/an564.pdf 
 
 3. If you need all voltages and currents use a 3 phase part only connecting 2 phases. 
 Dave)

dave.smith · Answer

Figure 1 and 2 are basically the same which are correct implementations just exchanging neutral for L2 . when usign figure 1 you have to assume Line and neutral may be swapped at installation the GND may be live even in figure 1. figure 2 gnd will be Live(L2 to earth) 
 3. What is the purpose of figure 3? Is this for protective impedance ? As far a voltage measurement it is similar to figure 1 and 2. 
 Dave

dave.smith · Answer

Per my understanding, if figure 1 and figure 2 maybe have Live to earth while Line and neutral swapped. The GND of ADE7953 is connected to neutral but nor connect to earth, right? Or have any standard connection compatible CNS & UL to suggest? Isolation may be required to meet UL and CNS safety requirements 
 
 Other questions: 
 1. The current of neutral must be measured by CT? Or just only measure L phase current is enough. If this is single phase not split with line and neutral only one CT is needed 
 2. If we not measure the current of neutral . Could IBP、IBN be used for leakage current measurement? You could try, phase b current will give you RMS of anything you put into the inputs. Size the ct and burden appropreately. How fast do you need to respond to the leakage that may be the issue. 
 3. If we would like IBP、IBN for leakage current measurement, have any sample code or scenario to implement this function? Thank you. This is just an RMS measurement or you may need to use waveform samples. I do not have code for this 
 Dave

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ADE7953 single phase connection for Dual live wire