ABB Remote I/O RIO600 - Page 129

Y t Y t Y t
osum CPS osum osum_
( ) ( ) ( )
2 1 2
= +
GUID-1067FA7D-089C-434E-BC37-51C550F270A5 V1 EN (Equation 12)
Y t Y t Y t Y t
osum CPS osum osum osum_
( ) ( ) ( ) ( )
3 1 2 3
= + +
GUID-76F70A50-2558-496C-B22E-E7235F2373A1 V1 EN (Equation 13)
Y t Y t Y t Y t Y t
osum CPS osum osum osum osum_
( ) ( ) ( ) ( ) ( )
4 1 2 3 4
= + + +
GUID-116F1B28-3898-4607-B3E8-E571497296DB V1 EN (Equation 14)
Y t Y t Y t Y t Y t Y
osum CPS osum osum osum osum osu_
( ) ( ) ( ) ( ) ( )
5 1 2 3 4
= + + + +
mm
t( )
5
GUID-927F5A3C-42E6-4893-99D5-F56B2F58ACA4 V1 EN (Equation 15)
Re
OSCILLATING DISCRETE
DFT-PHASORS
Y
osum_CPS
(t
5
)
_
Y
osum
(t
1
)
Y
osum
(t
2
)
Y
osum
(t
3
)
Y
osum
(t
5
)
Y
osum
(t
4
)
STABLE CUMULATIVE DFT-PHASOR
CALCULATED WITH CPS-TECHNIQUE
Re
ImIm
Y
osum
(t
1
)
Y
osum
(t
2
)
Y
osum
(t
3
)
Y
osum
(t
4
)
Y
osum
(t
5
)
_
_
_
_
_
_
_
_
_
_
GUID-3D60125B-0954-4E47-8FBB-32FF6CDD23E9 V1 EN
Figure 70: Cumulative Phasor Summing (CPS) principle
The CPS technique provides a stable directional phasor quantity despite of individual
phasors varying in magnitude and phase angle in time due to non-stable fault type such
as an intermittent earth fault. This is also true for harmonic components included in the
sum admittance phasor. Harmonics have typically a highly fluctuating character.
Harmonic components provide a more distinctive directional determination in
compensated networks than the fundamental frequency components. With higher
frequencies the compensation coil appears as a very high impedance and the
harmonics are not affected by the compensation coil and degree of compensation.
When harmonics are present, they cause the sum admittance phasor to behave as in
case of an unearthed network, where directional phasors point in fully opposite
directions in the faulty and healthy feeders.
The direction of the MFAPSDE function is defined by setting Directional mode to
“Forward” or “Reverse”. The operation characteristic is defined by tilted operation
sector as illustrated in
Figure 71. The characteristic provides universal applicability,
that is, it is valid both in compensated and unearthed networks, also if the
compensation coil is temporarily switched off. The tilt of the operation sector is
1MRS757488 H Section 6
Commissioning
RIO600 121
Installation and Commissioning Manual