ABB REG670 Commissioning Manual page 202

Section 13
Testing functionality by secondary injection
196
IED with an initial value below negative sequence current start level. No
output signals should be activated.
Note: If it is difficult to obtain pure negative sequence current for the
secondary injection test, a current corresponding to the two phase short-
circuit condition can be used. A two phase short-circuit gives a negative
sequence current of a magnitude: magnitude = (1/√3) · fault current.
5. Increase the injected current and note the value at which the step 1 of the
function operates. Start signal ST1 must be activated when amplitude of the
negative sequence current lies slightly above the start level I2-1>.
Corresponding trip signals TR1 and TRIP is activated after the pre-set time
delay has expired.
Note: Block or disable operation of step 2 when testing step 1 if the injected
current activates the step 2.
6. Decrease the current slowly and note the reset value.
7. Connect a trip output contact to a timer.
8. Set the current to 200% of the start level of the step 1, switch on the current
and check the definite time delay for trip signals TR1 and TRIP. Once the
measured negative sequence current exceeds the set start level I2-1>, the
settable definite timer t1 starts to count and trip signals is released after the
set time delay has elapsed. The same test must be carried out to check the
accuracy of definite time delay for ALARM signal.
Note: The output ALARM is operated by START signal.
9. If inverse time is selected the trip signals TR1 and TRIP operates after a time
corresponding to the formula:
This means that if current jumps from 0 to 2 times start and negative
sequence capability value of generator K1 is set to 10 s and current start level
I2-1> is set to 10% of rated generator current, then TR1 and TRIP signals
operates at time equal to 250 sec ± tolerance.
10. Repeat the above-described tests for the step 2 of the function excluding the
inverse time testing.
11. Finally check that start and trip information is stored in the event menu.
Example
CTprim
The CT ratios CT sec
following secondary currents are applied:
Generator protection REG670 2.2 IEC and Injection equipment REX060, REX061, REX062
1


I 2 1
− >



 100

[ ]
t s
=

(
Multiple of Start



for all three phases is 1000 A, IBase is 1000 A, and the
1MRK 502 073-UEN A


2





K K
⋅
2

)



Commissioning manual