Important Notes For This Procedure; Annunciations And Setting Examples; Verify Actual Programming Of Trip Relays And Signal Relays; Control Of Protective Elements By Discrete Inputs During Testing - Siemens 7UT51 Instruction Manual

16
Bench Testing
16.2

Important Notes for This Procedure

Note: Do not exceed the current limitations of the
7UT51
• Ensure that output contacts do not break currents
greater than their rating.
• Ensure that any control power or test value
applied to the relay does not exceed the
corresponding input's limit.
• Exceeding the contact or voltage limits may
damage the relay.
The current limitations (rms) of the CT inputs
associated with the transformer winding (or protected
object) and neutral CTs are:
7UT51
CONTINUOUS
RATED
CURRENT
RATING
CURRENT
I ≤ 20 AMPS
5 AMPS
I ≤ 4 AMPS
1 AMP
Table 16.1 Currents Limitations
Note: The rated current is on the nameplate.
Be especially mindful of the current limitations when
testing the high-set differential element, the upper
slope of the differential characteristic, the required
restraint current to activate the
through-fault-CT-saturation restraint, the high-set
element of the overcurrent backup protection, and the
thermal overload elements.
The current limitations for the CT input associated with
the highly sensitive tank leakage protection, terminals
[1D1-1D2] are:
Continuous Current Rating: I ≤ 15 AMPS
•
10 Second Current Rating: 15 AMPS < I ≤
•
100 AMPS
160
10 SECOND
CURRENT
RATING
20AMPS < I ≤ 100 AMPS
4 AMPS < I ≤ 20 AMPS
16.2.1 Annunciations and Setting
Examples
Event annunciations and setting options for the
addresses mentioned are as they appear in the
WinDIGSI software or the relay front panel. The titles
can vary between the software and the front panel of
the 7UT51.
After each test reset all targets and annunciations as
described in Section 16.10 on page 177.
16.2.2 Verify Actual Programming
of Trip Relays and Signal
Relays
For each test, the user should always verify the
operation of the relays and targets based on the
settings for the particular 7UT51 being tested.
Verification of the programming of trip relays and
signals relays is especially important during
installation testing. The user may have to add tests to
the procedure to verify each output relay is operating
as intended.
16.2.3 Control of Protective
Elements by Discrete
Inputs during Testing
The operational status of most of the protective
elements can be controlled by discrete inputs. Before
testing any element, determine if any such control is
intended, and apply (or remove) the necessary input
to allow testing.
16.3 Testing Transformer
Differential Protection
Note: Do not exceed relay's current, voltage, and
frequency capabilities when performing tests.
Testing a numerical relay with a test set is a quick
method of determining if a relay is correctly connected
and functioning as intended. The relay is tested by
applying currents to its inputs that simulate field
conditions, including the configuration (polarity and
wiring) of the CTs.
7UT51 v3
PRIM-2330C