FANOX SIA-C User Manual

Also see for SIA-C: User manual

Contents

www.fanox.com Rev.26 105/1885.12. Power supplyThe SIA-C equipment is designed to be self-powered using the cell current. It can also bepowered by a 12V battery and, optionally (which can be selected for each model) by anauxiliary 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 phaseThe SIA-C powers itself from the operating current through current transformers that areconnected to the line. Standard 5 A or 1 A secondary current transformers are used for thispurpose. Self power is achieved with very low levels of current: a minimum of 0.2 times therated single phase current, and this value is reduced to one half of the three-phase current. Inother words, the SIA-C equipment rated at 5 A current powers itself with 1 A of single phasecurrent and with 500 mA of three phase current, and the SIA-C rated at 1 A of current powersitself with 200 mA of single phase current and with 100 mA of three phase current. It isimportant to consider that, despite of the device starts up with those values and trip output isactivated in those values, to activate the other optional outputs (phase trip and neutral trip) it isneeded a minimum of 0.350 times the secondary rated single-phase current and a minimum of0.170 times the secondary rated three-phase current. These CTs do not need a large numberof VAs, because SIA-C self-regulates the charge of its self-power over the CT. Therefore, forlow 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 notrequire auxiliary power components (batteries). As a result, it is especially useful in any centreswhere auxiliary power is not available or cannot be guaranteed, and the facilities requireprotection with low levels of current.There is a self-power transformer per each phase (3 self-power transformers), separatingcurrent circuits completely. As a first idea, it could be possible using only two power supplytransformers but this possibility entails a disadvantage in case of single-phase faults; becausethe transformer associated to the circuit which is not in fault at this moment, would cause a riseof the level of self-power.5.12.2. Battery power: 12V, with a KITCOM adaptorThe power comes from two AA batteries (IEC LR06) of 1.5 Volts placed at the bottom of thedevice. The equipment has a small Dc/Dc power supply that raises the voltage till the required12 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 thevoltage is adequate.In addition to all the necessary to give the power supply, this device has two LED associatedwith the Rx and Tx lines of communication, and they are used to verify that there is data trafficbetween the PC and the SIA relay.It is useful for cases like commissioning operations, discharges and repairs to thetransformation center.Battery power guarantees the full operation of the equipment, including the trip. The possibilityof using external battery power, together with the possibility of activating the trip contact fromthe test menu, allows the trip circuit to be tested before the transformation center is poweredup.Using battery power does not block the RS232 communications port, as it can be usedsimultaneously.