Tettex 2293 - Yndx Mode 2 X 16 A ¦ 50 V (D)

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Theory
3.2.4 YNdx Mode 2x 16A ¦ 50V (D)
This supply mode is selected, when two the corresponding phases of the high and low voltage
side of an YNdx (x = 1, 3, 5, 7, 9, 11) transformer have to be measured. This mode is on
applicable to YNd transformers. It is intended to ideally magnetize and saturate the core, to
achieve a faster current balancing in the delta winding. The three power supplies are split to the
HV and LV side. The measuring current must be selected as follows:
I1 ≤ 16.0A
I2 ≤ 16.0A
The measuring circuit for a simultaneous measurement of HV and LV on phase A of an YNd1
transformer is illustrated below. YNd measuring mode must be set to “without Rn (Ph-Ph)”:
2
1
I
2
1
I
1
I
2
I
U
1
U
1
U
2
U
2
N
A
B
C
b
a
c
8A / 50V
8A / 50V
16A / 50V
The measured resistances are calculated as follows:
1
1
I
U
RR
AAN

(without Rn)
2
2
)(||
I
U
RRRR
cbaab

The operating area for the power supplies is the same as in mode C.