IMM 8001/8002 – Digital Motor Protection Relay
ICE / CEE
____________________________________________________________________________________________
IMU307-1 GB Ind. B
69
TESTS : Verification of the protection AGAINST SHORT-CIRCUITS [50]
CONNECTION, COEFFICIENT OF CORRECTION
Protection verification
Current injection
Coefficient
M
to be applied
Terminals
In =
1A
In =
5A
- single-phase
1.732
2-4 or 10-12
3-5 or 11-13
- balanced three-phase
1
2-4 phase 1
3-5 phase 1
10-12 phase 3
11-13 phase 3
Caution – the adjustment of coefficient K must be taken into account in the current to be injected :
K = In machine/IN
CT
Sequence of operations to be performed
Results to be obtained
The operating level is fixed and equal to
1.4 Ist>
(1.4 times the programmed
starting current: see function [48]).
There is no time-delay. The protection response time is about 70 ms.
Check of overcurrent unit
Check of fixed operating level I>>
Put into service the protection, and route it to a chosen unit.
Note the values of the operating level which is fixed and equal to
1.4 Ist>
Connect the current generator according to the desired connection,
deduce
M
Gradually increase the current up to the operating level by taking
M
into
account
I = 1.4 Ist> x
M
Check of response time
Preset the current to 1.5 times Ist>
I = 1.5 Ist> x
M
Cut off the current.
Inject the current.
Note : When function [50] is disabled (use of a fuse contactor), the response
time for function [48] and function [51N] cannot be less than 250 ms to
ensure fuse protection selectivity.
On reaching the operating level :
the selected relay must be energised,
the Start Function and Internal Trip indicator
LEDs must illuminate,
the fault message and related informations must
be displayed.
The response time found shall be less than 100
ms.