ABB REL650 Applications Manual page 171

1MRK 506 334-UUS A
Application manual
tP2 = 10 ms
Consider RLdInFw = 75.0Ω.
Do not forget to adjust the setting of load encroachment resistance
RLdFwd in Phase selection with load encroachment (FDPSPDIS, 21) to
the value equal to or less than the calculated value RLdInFw. It is at the
same time necessary to adjust the load angle in FDPSPDIS (21) to follow
the condition presented in equation 91.
Index PHS designates correspondence to FDPSPDIS (21) function and
index PSD the correspondence to ZMRPSB (68) function.
é
tan(
³
arctan
LdAngle
ê
PHS
ë
EQUATION1737-ANSI V1 EN
Consider equation 92,
= °
j 25
=
LdAngle
max
PSD
EQUATION1739-ANSI V1 EN
then it is necessary to set the load angle in FDPSPDIS (21) function to not less than
equation 93.
é
tan(LdAngle
³
LdAngle arctan
ê
PHS
ë
EQUATION1738-ANSI V1 EN
It is recommended to set the corresponding resistive reach parameters in reverse direction
(RLdOutRv and kLdRRv) to the same values as in forward direction, unless the system
operating conditions, which dictate motoring and generating types of oscillations,
requires different values. This decision must be made on basis of possible system
contingency studies especially in cases, when the direction of transmitted power may
change fast in short periods of time. It is recommended to use different setting groups for
operating conditions, which are changing only between different periods of year (summer,
winter).
System studies should determine the settings for the hold timer tH. The purpose of this
timer is, to secure continuous output signal from Power swing detection function
ù
LdAngle )
PSD
ú
û
KLdRFw
ù
)
=
PSD arctan
ú
û
kLdRFw
Section 6
Impedance protection
°
é ù
tan(25 )
= °
37.5
ê ú
ë û
0.61
(Equation 91)
(Equation 92)
(Equation 93)
165