ABB RED650 Applications Manual page 148

Section 7
Impedance protection
142
Index PHS designates correspondence to FDPSPDIS or FRPSPDIS
function and index PSD the correspondence to ZMRPSB function.
tan
³
ArgLd arc tan
PHS
EQUATION1353 V2 EN-US
Consider equation 93,
j
= =
ArgLd 25
PSD max
EQUATION1354 V1 EN-US
then it is necessary to set the load argument in FDPSPDIS or FRPSPDIS function
to not less than equation 94.
é
tan
³
ArgLd arc tan
ê
PHS
ë
EQUATION1355 V1 EN-US
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, require 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 the Power swing detection
function (ZMRPSB) during the power swing, even after the transient impedance
leaves ZMRPSB operating characteristic and is expected to return within a certain
time due to continuous swinging. Consider the minimum possible speed of power
swinging in a particular system.
The tR1 inhibit timer delays the influence of the detected residual current on the
inhibit criteria for ZMRPSB. It prevents operation of the function for short
transients in the residual current measured by the IED.
The tR2 inhibit timer disables the output START signal from ZMRPSB function, if
the measured impedance remains within ZMRPSB operating area for a time longer
than the set tR2 value. This time delay was usually set to approximately two
seconds in older power-swing devices.
( )
ArgLd
PSD
kLdRFw
°
( )
ù é
ArgLd
=
PSD
arc tan
ú ê
kLdRFw
û ë
1MRK 505 393-UEN B
( )
ù
°
tan 25
= °
37.5
ú
0.61
û
Line differential protection RED650 2.2 IEC
Application manual
(Equation 92)
(Equation 93)
(Equation 94)