GC315xx and GC400xx Technical Manual 71
The P.0107 and P.0139 parameters are used for setting the current values of the CTs primary
and secondary.
Using the P.0124 parameter you can define whether the CTs on the three phases are
positioned on the generator (as shown in the drawing above) or on the load, so as to measure
also the power absorbed by the mains. This also has an effect on the operation sequence and
the display of symbols and currents and power/energy measures that appear on the menu
pages M.01, M.06, M.07, M.08 and M.09.
The device allows for acquiring a fourth measure of current, usable for example for a
differential protection. By default, the fourth measure is not used.
The board is configured for the connection of a current transformer (C.T.) for the measure of
the current: if it is required to use a toroid (instead of a C.T.) it is necessary to ask for the
special option in phase of order (E6202111000XX).
The parameters P.0108 and P.0140 define the currents of the CTs primary and secondary for
the auxiliary current.
The P.0130 parameter determines where the auxiliary current is measured:
0- On the generator
1- On the loads
2- On the mains.
The P.0131 parameter allows you to select if and how the auxiliary current is used:
0- Not used
1-General use.
2-Neutral on the generator
Settings 1 and 2 allow to establish a threshold (par. P.0367 and P.0368) and to determine
what action should be taken when the same is exceeded. The setting 2 allows the controller
to calculate the genset current differential protection (see 5.13.1.1). Settings 2 and 3 allow to
set a threshold (par. P.0377 and P.0378) on the differential current: when exceeding it, an
alarm is activated.
You can configure a digital input with the function DIF.2704 – “Disable the protections on the
4th current”: If the input is active, the thresholds, even if set, are ignored and no fault is
generated in case the thresholds are exceeded.
To use the current differential protection, the CT of the auxiliary current should measure the
current on the neutral of the generator and the P.0131 parameter should be set as “2 – Neutral
on the generator”.
That way, the device calculates the vector sum of all the four currents measured and therefore
detects and calculates any imbalance, allowing you to implement, by means of the parameters
P.0377 and P.0378 a threshold for the maximum current differential protection.
The triggering of the protection generates a lock.
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