ABB RET670 - Page 370

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 or
FRPSPDIS, 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) or FRPSPDIS (21) to follow the condition presented in
equation
309.
Index PHS designates correspondence to FDPSPDIS (21) or
FRPSPDIS (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 309)
Consider equation 310,
max
25
PSD
LdAngle j = = °
EQUATION1739-ANSI V1 EN (Equation 310)
then it is necessary to set the load angle in FDPSPDIS (21) or FRPSPDIS (21) function
to not less than equation 311.
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 311)
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).
Section 3 1MRK504116-UUS C
IED application
364
Application manual