Accura 2300/2350 User Guide
Chapter 5 Measurement Description
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2011 Rootech Inc. All Rights Reserved
Page 193
3-Phase 3-Wire
Voltage connection
The use of 2PT or 3PT for 3-phase 3-wire voltage wiring is the same for Accura 2300, only the installation cost
is different.
3-phase current can be measured by setting two or three single-phase modules to operate as a three-phase
group device. The advantage obtained by using three modules compared to using two modules is that the
leakage current can be detected by calculated residual current which is the sum of three-phase currents.
Careful attention should be paid to small leak current judgments due to accuracy errors of CTs for each phase.
Fig 5.2 2PT 3CT Wiring, 3P3W Connection
Voltage measurement
Vector Diagram
Item
Description
V
1
V
2
V
3
V
r
= V
1
+
V
2
+V
3
V
N
V
n
= V
r
/ 3
Line-to-neutral voltage
sensing
▶
Line-to-neutral voltage[V
1
, V
2
, V
3
] sensing based
on N-terminal voltage
Residual voltage
calculation
▶
From the line-to-neutral voltage sensed
Vr = V
1
+ V
2
+ V
3
Virtual neutral voltage
calculation
▶
Calculation of virtual neutral voltage by dividing
3.
Vn = Vr/3
▶
Virtual neutral point is the center of gravity of a
triangle composed of V
1
, V
2
, V
3
Summary of Contents for Accura 2300 Front
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