Visual Inspection; Maintenance Tests; Preparation; Recording - Hitachi Relion 670 Series Commissioning Manual

Section 13
Commissioning and maintenance of the fault clearing system
13.2.1

Visual inspection

Prior to testing, the protection IEDs should be inspected to detect any visible damage that may have
occurred (for example, dirt or moisture deposits, overheating).
Make sure that all IEDs are equipped with covers.
13.2.2

Maintenance tests

To be made after the first half year of service, then with the cycle as proposed above and after any
suspected maloperation or change of the IED setting.
Testing of protection IEDs shall preferably be made with the primary circuit de-energized. The IED
cannot protect the circuit during testing. Trained personnel may test one IED at a time on live circuits
where redundant protection is installed and de-energization of the primary circuit is not allowed.
Hitachi Power grids protection IEDs are preferably tested by aid of components from the
COMBITEST testing system described in information B03-9510 E. Main components are RTXP
8/18/24 test switch usually located to the left in each protection IED and RTXH 8/18/24 test handle,
which is inserted in test switch at secondary testing. All necessary operations such as opening of trip
circuits, short-circuiting of current circuits and opening of voltage circuits are automatically performed
in the right order to allow for simple and safe secondary testing even with the object in service.
13.2.2.1

Preparation

Before starting maintenance testing, the test engineers should scrutinize applicable circuit diagrams
and have the following documentation available:
• Test instructions for protection IEDs to be tested
• Test records from previous commissioning and maintenance tests
• List of valid settings
• Blank test records to fill in measured values
13.2.2.2

Recording

It is of utmost importance to carefully record the test results. Special test sheets covering the
frequency of test, date of test and achieved test values should be used. IED setting list and protocols
from previous tests should be available and all results should be compared for differences. At
component failures, spare equipment is used and set to the requested value. A note of the exchange
is made and the new measured values are recorded. Test records for several years of testing should
be stored in a common file for a station, or a part of a station, to give a simple overview of the period
of testing and achieved test values. These test records are valuable when analysis of service
disturbances shall be done.
13.2.2.3

Secondary injection

The periodic maintenance test is done by secondary injection from a portable test set. Each
protection shall be tested according to the secondary injection test information for the specific
protection IED. Only the setting values adopted shall be checked for each protection function. If the
discrepancy between obtained value and requested set value is too big the setting should be
adjusted, the new value recorded and a note should be made in the test record.
13.2.2.4

Alarm test

When inserting the test handle the alarm and event signalling is normally blocked. This is done in the
IED by setting the event reporting to Off during the test. This can be done when the test handle is
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