Bench Testing; Required Test Equipment - Siemens 7UT51 Instruction Manual

7UT51 v3
16

Bench Testing

Hazardous voltage or current.
Can cause death, serious personal
injury, or property damage.
Only qualified personnel should test or
commission a relay. Read and understand
this manual and the manuals for any test
equipment before proceeding.
Before performing work on current
transformer wiring, always short-circuit
the secondary of the current transformers.
This chapter describes procedures for bench testing a
7UT51 relay, such as for acceptance tests or testing of
applied settings. A 7UT51 has many protective
elements and control features that can be used in a
variety of ways. Testing all of the elements and control
features, in the many different ways they can be used,
is not recommended. Such testing would be time
consuming. This chapter provides typical tests for
protective functions likely to be used. Testing of all
applied "in-service" settings and all required protective
functions is recommended.
Sample typical applications are used to illustrate how
to calculate test values. Actual test values for a
specific application must be calculated from that
application's data.
The procedures take into account that the protection
settings may vary, but they assume that the relay's
contact inputs, contact outputs, and LEDs are
configured with their default values (unless otherwise
specified). If they have been configured differently, the
user must determine the expected behavior of the
relay and compare it to the observed results of the
procedure.
PRIM-2330C
16.1 Required Test
Equipment
This procedure requires the following test equipment:
• Power source matching the rating of the 7UT51
• Two variable current sources with the following
capabilities:
- Accuracy of +/- 2% or better over the entire
output range
- One source that can provide 20 amps (if
7UT51 rated for 5 amps)
- One source that can provide 120 Hz, 180 Hz,
240 Hz, and 300 Hz current
- Both sources can be individually or
simultaneously turned on and off
• A timer that can be started when either a current
source is turned On or Off, and stopped by either
the opening or closing of a dry contact. The
accuracy should be +/- 2% or better. A timer
built-in to a test-set with one (or both) of the
current sources is preferred.
• An ohmmeter, or other sensor for detecting a
transition of a dry contact
• An on/off switch to apply DC voltage to discrete
inputs of the 7UT51
• Calculator with the capability of performing sine,
cosine, and natural log functions.
The following is not required, but highly
recommended:
• A timer with +/- 2% accuracy or better, that can be
started by the opening or closing of a dry contact,
and stopped by the opening or closing of a dry
contact.
• Computer with WinDIGSI software and cable
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Bench Testing
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