GE 745 Instruction Manual page 243

CHAPTER 7: COMMISSIONING
7.2 Preliminary Work
7.2.1 Description
CAUTION
745 TRANSFORMER PROTECTION SYSTEM – INSTRUCTION MANUAL
 Review appropriate sections of this manual to familiarize yourself with
the relay. Confidence in the commissioning process comes with
knowledge of the relay features and methods of applying settings.
 Verify the installation to ensure correct connections of all inputs and
outputs.
 Review the relay settings and/or determine features and settings
required for your installation. In large utilities a central group is often
responsible for determining which relay features will be enabled and
which settings are appropriate. In a small utility or industrial user, the
on-site technical person is responsible both for the settings and also for
the complete testing of the relay.
 Set the relay according to requirements.
Ensure that the correct relay model has been installed. A summary table
is available in this manual for users to record all the relay settings.
 When the testing is completed, verify the applied relay settings, and
verify that all desired elements have been enabled, using the EnerVista
745 Setup software or the relay front panel.
 Verify that the relay rated AC current matches the CT secondary value.
 Verify that the relay rated AC voltage matches the VT secondary value.
 Verify that the relay rated frequency setting matches the power system
frequency.
 Open all blocking switches so as not to issue an inadvertent trip signal to
line breakers.
 Verify that the auxiliary supply matches relay nameplate. Turn the
auxiliary supply on.
 Verify that all grounding connections are correctly made.
To facilitate testing it is recommended that all functions be initially set to Disabled. Every
feature which will be used in the application should be set per desired settings, enabled for
the specific commissioning test for the feature, then returned to Disabled at completion of
its test. Each feature can then be tested without complications caused by operations of
other features. At the completion of all commissioning tests all required features are then
Enabled.
It is necessary to keep track of modifications/changes made to settings during the
course of these commissioning steps and ensure that all settings are returned to the
'in-service' values at the end of the tests, prior to placing the relay into service.
PRELIMINARY WORK
7–5