Hioki 3196 - Page 206

12.4 Formulae
200
RMS voltage U (V rms)
Single-phase 2-wire
1P2W
Single-phase 3-wire
1P3W
Three-phase 3-wire
3P3W2M
Three-phase 3-wire
3P3W3M
Three-phase 4-wire
3P4W
U1
U4
U1
U2
U4
line-to-line voltage Line-to-line voltage Phase-to-neutral
voltage
U1
U2
U3
U4 U4 U4
Phase-to-neutral
voltage
Phase-to-neutral
voltage
Line-to-line voltage
U4 U4
Line-to-line voltage Line-to-line voltage Phase-to-neutral
voltage
Phase-to-neutral
voltage
Phase-to-neutral
voltage
Line-to-line voltage
• RMS voltage is calculated about once every10 cycles at 50 Hz or every 12 cycles at 60 Hz with a single
wave (256 points).
• Make the neutral point the center and calculate the phase-to-neutral voltage for three-phase 3-wire con-
nections. The RMS voltage for CH4 can be calculated regardless of the connection method.
• Use the line-to-line voltage calculated for three-phase 3-wire and three-phase 4-wire connections to cal-
culate Δ V10.(See the formula forΔ V10.)
c: measured channel M: number of samples s: number of sampling points
U
c
1
M
-----
Ucs
()
2
S0=
M1–
∑
=
U12
1
M
-----
U
1s()
2
S0=
M1–
∑
=
U32
1
M
-----
U
2s()
2
S0=
M1–
∑
=
U12
1
M
-----
U
1s()
2
S0=
M1–
∑
=
U23
1
M
-----
U
2s()
2
S0=
M1–
∑
=
U31
1
M
-----
U
3s()
2
S0=
M1–
∑
=
U
1
1
M
-----
U1s U3s–
3
----------------------
⎝⎠
⎜⎟
⎛⎞
2
S0=
M1–
∑
=
U
2
1
M
-----
U2s U1s–
3
----------------------
⎝⎠
⎜⎟
⎛⎞
2
S0=
M1–
∑
=
U3
1
M
-----
U3s U2s–
3
----------------------
⎝⎠
⎜⎟
⎛⎞
2
S0=
M1–
∑
=
U
12
1
M
-----
U
1s U2s–()
2
S0=
M1–
∑
=
U
23
1
M
-----
U
2s U3s–()
2
S0=
M1–
∑
=
U
31
1
M
-----
U3s
U1s–()
2
S0=
M1–
∑
=
U
ave
1
2
---
U1 U2+()=
Uave
1
2
---
U12 U32+()=
U
ave
1
3
---
U12 U23 U31++()=
U
ave
1
3
---
U1 U2 U3++()=
U
ave
1
3
---
U1 U2 U3++()=
U
ave
1
3
---
U12 U23 U31++()=