12.4.11.1
Verifying the settings
GUID-708C4033-3111-481F-9868-FF207C18C9F9 v1
The test of the out-of-step protection function is made to verify that the trip is issued if the
following events happen.
•
the impedance, seen by the function, enters the lens characteristic from one side and
leaves it from the opposite side
•
the trip is issued according to the settings
TripAngle and tBreaker
The tripping zone needs to be detected and confirmed. The test may be performed by taking
into account the following key points that are shown in Figure
•
the point RE (RE = Receiving End)
•
the intersection between the line segment SE-RE and the X-line, which is defined through
the setting
ReachZ1
•
the point SE (SE = Sending End)
I = I(50 Hz) + I(49.5 Hz)
IEC10000141 V2 EN-US
Figure 50: Trajectory of the impedance Z(R, X) for the injected current with two
components: a 50 Hz component and a 49.5 Hz current component
The test of the out-of-step protection function requires the injection of the analog quantities
for a quite long time. The rating of the analogue channels is considered in order to avoid any
hardware damage. The test current is lower than the continuous permissive overload current
I
ovrl
of the protection current channels of the transformer module.
If the rated secondary current I
rs
of the analog channel is 1 A, then the maximum current test I
ts
is
I
I
I
A
ts
ovrl
rs
≤
= ×
=
4
4
EQUATION14041 V1 EN-US
(Equation 1)
If the CT of the generator has ratio 9000/1 A, then in primary values
I
I
I
I
I
A
t
ovrl p
ovrl
rp
rs
≤
=
×
= ×
=
,
4
9000
1
36000
EQUATION14042 V1 EN-US
(Equation 2)
Reference is made to the numerical values of the example, explained in the “Setting guidelines”
of the
Application Manual. A test current equal to 2.5 time the base current of the generator is
chosen; this choice is related to the selected test voltage that is applied while testing the point
SE and RE.
Section 12
1MRK 502 067-UEN B
Testing functionality by secondary injection
132
Commissioning manual
