Secondary Injection; Primary Injection - Siemens 7SG164 Ohmega 400 Series Manual

Connect together all of the V.T terminals and measure the insulation resistance between these terminals and all
of the other relay terminals connected together and to earth.
Connect together the terminals of the DC auxiliary supply circuit and measure the insulation resistance between
these terminals and all of the other relay terminals connected together and to earth.
Connect together the terminals of the DC status input circuits and measure the insulation resistance between
these terminals and all of the other relay terminals connected together and to earth.
Connect together the terminals of the output relay circuits and measure the insulation resistance between these
terminals and all of the other relay terminals connected together and to earth.
Satisfactory values for the various readings depend upon the amount of wiring concerned. Where considerable
multi-core wiring is involved a reading of 2.5 to 3.0 Megaohms can be considered satisfactory. For short lengths
of wiring higher values can be expected. A value of 1.0 Megaohm or less should not be considered satisfactory
and should be investigated.
Remove temporary connections.

5.2 Secondary Injection

Select the required relay configuration and settings for the application.
Configure the status input and output relays to the requirements of the schematic diagrams. Also select the
scheme logic applicable to the protected circuit from the system configuration menu, as well as the relevant CT
and VT ratios.
The relay is equipped with comprehensive self testing routines which automatically check correct initialisation
and processing operation. The "Protection Healthy" LED is under software control and if, after application of the
correct DC supply, it gives a steady light this is an indication that the relay is functioning correctly. A flashing
LED, or no LED light indicates faulty equipment.
withdrawable modules, faulty relays must be returned to Siemens.
Using the automatic test equipment, inject 1 amp 3 phase into the current circuits of the relay and apply 63.5
volts 3 phase to the voltage circuits. Check that the fascia display indicates the correct corresponding primary
currents and voltages applicable to the relevant instrument transformer ratios selected. If the metering displays
on the fascia are correct all the relay operations under load and fault conditions will be correct.
If possible each status input should be energised in turn and checked for correct operation and fascia display.
Check the operation of each output relay by selecting it in the "Test Plant Control" setting.
Correct operation of all the above checks will ensure that the relay will perform correctly. If added confidence is
required, each element can be individually tested with the appropriate current and voltage from the test set, and
the settings verified.

5.3 Primary Injection

Current Transformer Connections
Check that the supply links and fuses are arranged as follows:-
•
Trip links removed
•
Voltage transformer links removed
•
Earth links inserted
•
Current transformer connected for normal operation
•
To test the current transformers for ratio, relative polarity and soundness of the secondary leads, connect
the circuit as shown in figure 1. Inject at least 50% of the rated primary current into the red-yellow phases -
record the ammeter readings in Table 1. Check that:-
•
Meters A, A1, A2 and relay meter readings Ia and Ib give the same reading (corrected if necessary, for
different C.T ratios).
•
Meters A3, A4 and relay meter readings Ia and Ix give negligible current readings
•
Repeat the above test, but with primary current injected into the yellow-blue phases. Record current
recordings in Table 1. Check that:-
•
Meters A, A2 and A3 and relay meter readings 1b and Ic give the same reading (corrected if necessary, for
different C.T. ratios).
•
Meters A1 and A4 and relay meter readings Ia and Ix give negligible current readings.
©2011 Siemens Protection Devices Limited
7SG164 Ohmega 400 Series Commissioning
As there are no user serviceable components in the
Chapter 9 Page 4 of 6