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.
tan( )
arctan
PSD
PHS
LdAngle
LdAngle
KLdRFw
³
é ù
ê ú
ë û
EQUATION1737-ANSI V1 EN (Equation 91)
Consider equation 92,
EQUATION1739-ANSI V1 EN (Equation 92)
then it is necessary to set the load angle in FDPSPDIS (21) function to not less than
equation 93.
PSD
PHS
tan(LdAngle )
tan(25 )
LdAngle arctan arctan 37.5
kLdRFw 0.61
°
³ = = °
é ù
é ù
ê ú
ê ú
ë û
ë û
EQUATION1738-ANSI V1 EN
(Equation 93)
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
1MRK 506 334-UUS A Section 6
Impedance protection
165
Application manual
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