ABB A43 User Manual page 59

Technical Description
The formula to use for this calculation is:
Formula
Max pulse frequency = 1000*3600 / U / I /n / (Ppause + Plength)
where U and I is the estimated maximum element voltage (in volts) and current
(in amperes), n the number of elements (1 - 3). Plength and Ppause are the pulse
length and the required pulse pause (in seconds). A reasonable minimum pulse
length and pulse pause is 30 ms which conforms to the S0 and IEC standard.
Note –
CT and VT for the external transformers are programmed into the meter.
In a direct connected 3-element meter with estimated maximum voltage and cur-
Example 1
rent of 250 V and 65 A and pulse length 100 ms and required pulse pause 30 ms,
the maximum allowed pulse frequency will be:
1000 * 3600 / 250 / 65 / 3 / (0.030 + 0.100)) = 568 impulses / kWh (kvarh)
In a transformer connected 3-element meter with estimated maximum voltage and
Example 2
current of 63 * 100 V = 6300 V (VT ratio 100) and 6 * 50 A = 300 A (CT ratio
50) and pulse width 100 ms and required pulse pause 30 ms the maximum allowed
pulse frequency will be:
1000 * 3600 / 6300 / 300 / 3 / (0.030 + 0.100) = 6.16 impulses / kWh (kvarh)
2CMC48001M0201
Revision: C
U and I have to be the primary values in a transformer connected meter if the
59 A43/A44
User Manual