FANOX SIA-C, Руководство пользователя

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5.12. Power supply
The SIA-C equipment is designed to be self-powered using the cell current. It can also be
powered by a 12V battery and, optionally (which can be selected for each model) by an
auxiliary power source (24 Vdc, 48 Vdc,110 Vac, 230 Vac or 85-265 Vac/dc).
5.12.1. Self Power: CT-5 A or CT-1 A, 0,2 x In rated in single phase
The SIA-C powers itself from the operating current through current transformers that are
connected to the line. Standard 5 A or 1 A secondary current transformers are used for this
purpose. Self power is achieved with very low levels of current: a minimum of 0.2 times the
rated single phase current, and this value is reduced to one half of the three-phase current. In
other words, the SIA-C equipment rated at 5 A current powers itself with 1 A of single phase
current and with 500 mA of three phase current, and the SIA-C rated at 1 A of current powers
itself with 200 mA of single phase current and with 100 mA of three phase current. It is
important to consider that, despite of the device starts up with those values and trip output is
activated in those values, to activate the other optional outputs (phase trip and neutral trip) it is
needed a minimum of 0.350 times the secondary rated single-phase current and a minimum of
0.170 times the secondary rated three-phase current. These CTs do not need a large number
of VAs, because SIA-C self-regulates the charge of its self-power over the CT. Therefore, for
low current levels, SIA-C is a charge which is continuously reduced when the current increases,
avoiding the CT saturation.
The equipment is maintenance free when this type of power supply is used, as it does not
require auxiliary power components (batteries). As a result, it is especially useful in any centres
where auxiliary power is not available or cannot be guaranteed, and the facilities require
protection with low levels of current.
There is a self-power transformer per each phase (3 self-power transformers), separating
current circuits completely. As a first idea, it could be possible using only two power supply
transformers but this possibility entails a disadvantage in case of single-phase faults; because
the transformer associated to the circuit which is not in fault at this moment, would cause a rise
of the level of self-power.
5.12.2. Battery power: 12V, with a KITCOM adaptor
The power comes from two AA batteries (IEC LR06) of 1.5 Volts placed at the bottom of the
device. The equipment has a small Dc/Dc power supply that raises the voltage till the required
12 volts to operate the equipment and that is plugged into the front RS232 communications port
(KITCOM).
The equipment has a micro-switch that feeds the power supply with a LED (ON) when the
voltage is adequate.
In addition to all the necessary to give the power supply, this device has two LED associated
with the Rx and Tx lines of communication, and they are used to verify that there is data traffic
between the PC and the SIA relay.
It is useful for cases like commissioning operations, discharges and repairs to the
transformation center.
Battery power guarantees the full operation of the equipment, including the trip. The possibility
of using external battery power, together with the possibility of activating the trip contact from
the test menu, allows the trip circuit to be tested before the transformation center is powered
up.
Using battery power does not block the RS232 communications port, as it can be used
simultaneously.