SIA-B Standard CT’s

Reliable Technology in Protection Solutions


Advanced OC&EF Self-Powered Protection Relay

SIA B is Overcurrent Protection Relay with Self-powered and dual powered (Self-powering + Auxiliary power) options.

Impeccably suited for protection and distribution systems, with minimal space requirement, SIA-B compact relay provides a comprehensive range of functions in an amazingly compact and space-saving housing.

The real advantage is that the installation and subsequent maintenance of external batteries is eliminated. The innovative relay is Self-powered using the operating current through three /1 (<2VA) standard current transformers fitted on the lines. These transformers are also used to obtain current measurements. Besides, SIA-B Relay can be used with auxiliary power supply (24-230 Vac/dc). The operating costs of the centre are reduced.

SIA-B Standard CT’s Protection Relay offering a high performance previously available only in relays with Vaux:

  • Remote communications for SCADA (Modbus or DNP3.0 protocols).
  • Up to 10 COMTRADE records.
  • Advanced functions.
  • Completely configurable I/O thanks to advanced logic.

Ultra-fast SOTF
Very low start-up levels and minimum consumption <2 VA
Compact design

Data Sheet

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  • Dual & Self powered OC&EF protection relay (with universal auxiliary voltage) using the operating current through /1 standard CTs.
  • With LOAD DATA PROFILING (current demand).
  • Stores up to 1024 events and DFR (20 fault reports in data format and 10 reports in COMTRADE format) in non-volatile RAM memory.
  • Configurable inputs, outputs and leds thanks to Programmable Logic Control (PGC).
  • Test menu allows the trip circuit to be tested before the transformation center is powered up.
  • With LEDs maintaining their position even though the relay loses the supply.
  • Self diagnosis of the status (WATCHDOG) through leds and physical outputs.
  • Internal Commissioning battery. (Lithium battery: 20 years lifetime).
  • High electomagnetic compatibility.
  • Low power consumption.
  • In Self powered mode, SIA-B starts-up from 75 mA (in secondary) in three phase system/160 mA (in secondary) in single phase system.
  • Micro USB front port connection (ModBus RTU protocol) for local communication. Remote communication through rear RS485 (ModBus RTU or DNP 3.0 selectable by general setting).

50 Instantaneous phase overcurrent

51 Inverse time overcurrent

49T External trip

51G Inverse time measured neutral overcurrent

50G Instantaneous measured neutral overcurrent

46 Phase balance current protection

49 Thermal overload

SHB Second Harmonic Blocking

CLP Cold Load Pickup

52 Breaker wear monitoring

50BF Circuit Breaker Failure

68 Zone selection interlocking

PGC Programmable logic control

TB Trip Block for switch disconnector

Communication Software for SIA & SIL protection relays

The SICom PC software has been designed and programmed to gain access to all of Fanox relays information, to modify the settings and configuration, check states and measurements and to analyse and save events and fault reports using a graphic-friendly user interface.

SICom software works with the Windows® Windows 7, Windows 8, Windows 8.1 and Windows 10 operating system.

  • General data reading: Complete model, Version, Serial number, etc.
  • States reading
  • Measurements reading
  • Reading and changing settings
  • Reading and changing configuration
  • Reading and deleting events
  • Reading and deleting fault reports
  • Reading and deleting demand current (load data profiling)
  • Reading and saving oscillographic records in Comtrade format
  • Changing the user passwords
  • Saving and Loading settings files
  • Saving and Loading configuration files
  • Saving events and fault reports
  • Saving demand current (load data profiling)
  • Date-time synchronization
  • Configuring the communication parameters
  • Reading and changing counters
  • Commands for opening and closing the circuit breaker and block/unblock the recloser
  • Configuration of the inputs
  • Configuration of the outputs
  • Configuration of the causes that start a Fault Report

The update of the software does not require any user´s action, this is, if the computer is connected to Internet, SICom updates itself when it is started.
It will allow you to prepare all the settings and relay configurations without having the relay connected to the PC (offline mode), reducing engineering and commissioning time.
SICom program uses Modbus protocol, so only the ports with this protocol can be used to establish the communication.

Striker – PRT

  • This is a single effect solenoid. The striker is spring operated.
  • The striker is activated by low-power polarised electrical signal supplied by the relay in case of a fault.
  • The striker is reset to its starting position manually.

Auxiliary Battery Power Supply – KITCOM

  • The KitCom is an adapter to supply SIA relays through the front communication port, allowing the communication with the computer simultaneously.
  • This adapter is very useful in the commissioning processes of the transformation centres, allowing full verification of the centre, without any auxiliary power supply.
  • The equipment has a microswitch 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.
SIA RANGESIA-B Specific CT'sSIA-B Standard CT'sSIA-C Standard CT'sSIA-F
Auxiliary Supply24Vdc
24-230 Vac/dc24Vdc
48 Vdc
110-230 Vac/Vdc
24-220 Vcc / 48-230 Vac
Self Power Supply3.2 A for CT08-5 6.4 A for CT16-5 12.8 A for CT32-5 25.6 A for CT64-5 51.2 A for CT128/5 102.4 A for CT256/5 (x3)0,075 In (x3)0,1 In (x3)
External batteryUSB cable / Power bankUSB cable / Power bankKITCOMUSB cable / Power bank
Internal battery√ (*)√ (*)
Consumption0,5 W1,5 W0,5 W1,5 – 2,2 W
CTSpecific CTStandard CT/1A - 2VAStandard CT/1A - 2.5VA Standard CT/5A - 5VAStandard CT/1 - 0,5VA Standard CT/5A - 0.5VA
74TCS 1
Trip Block111
68 Zone Selection interbloking111
PGCProgrammable LogicV3V3V3V3
Sett. Group243/43
Inputs--- EXT.TRIP3 DI--- EXT.TRIP 2DI 2DI + EXT.TRIP--- 2DI
Outputs--- 2NC-NO3 NC-NO--- 2 NC-NO 3 NO1 NO + 1 NC-NO
Output for STRIKER24 Vdc – 135 mJ24 Vdc – 135 mJ24 Vdc – 135 mJ
LEDs2 LEDs 2 LEDs +1MAG.FLAG4 LEDs3 LEDs + 1 MAG.FLAGS 3 LEDs + 3 MAG.FLAGS3 LEDs configurable
HMI20X2 LCD + 7/8 keys20X2 LCD + 8 keys20X2 LCD + 7/8 keys20X2 LCD + 7 keys
Fault Report420204
Oscillography10 records x 50 cycles10 records x 50 cycles1 record x 22 cycles
Current demand
Local Port (frontal)USBMicro USBRS232USB
Remote Port (rear)RS485RS485RS485RS485
Communications ProtocolsModBus RTUModBus RTU ModBus RTU or DNP3.0ModBus RTU ModBus RTU or IEC60870-5-103ModBus RTU DNP3.0
Size of (HxW)Vertical: 120,65 x 167,80 mm
Horizontal: 185,80 x 102,7 mm
90 X 245 mmVertical Compact: 177 x 155 mm
Vertical Standard: 177 x 189 mm
Horizontal: 177,8 x 290,3 mm
167,80 x 120,65 mm

Product quality is something we take very seriously and reliable testing is a key point.

We have expanded our testing capabilities to cope with new developments of protection relays and higher demand for our devices.

The additional functions required by our customers imply longer and more complex testing procedures.

Save Money using ONE Self-powered Relay for TWO Applications

A relay with different settings for regular operation and maintenance tasks is a requirement that is gaining more and more important not only to speed up the process, but also to comply with newer and severer safety procedures.

So far, two relays, one for each application, are installed. Still, this solution is not practical considering the compact sizes of the RMUs and the importance of finding economical solutions for this purpose.

Fanox SIAB relay is provided with four separate settings groups that will allow the user to set different settings depending on the application. The relay is provided with configurable inputs that are activated without external supply. By activating the corresponding inputs the relay will change automatically to the desired group. Besides, if configurable LEDs are used to indicate the settings group that the relay is working with.

SIA-B relay becomes the best and more reliable solution to save money, to facilitate the settings process, and to offer the best protection even when auxiliary supply is not available.

Multiple options for powering and communication

Related Products

SIA-B Specific CT’s
Dual & Self-Powered Protection Relays

Specific CTs

Fanox SIA-B Specific CT’s is a powerfull solution for overcurrent protection. This relayis the perfect choice if you look for a competitive and complete solution composed by relay + CTs for overcurrent protection while having all functions required for a maximum safety.

Protection functions:

  • 50 + 50/51 + 50N + 50/51N.
  • 49 + 49T + TB as additional protection functions.

Dual & Self-powered Protection Relays

Standard /1 or /5 CTs

Fanox SIA-C possibility of working with both /1 and /5 standard CTs makes it our safest choice for Overcurrent and Earth Fault Protection. Different sizes and models besides being withdrawable and Self-Powered makes the installation and maintenance much easier and simple. It also allows you to adapt some monitoring and auto-recloser functions in order to have some extra control and wider protection.

Protection functions:

  • 50 + 50/51 + 50N/G + 50/51 N/G + 86 + PLC.
  • 49T + CLP + 68 + 50_2 + 50N/G_2 + 52 + 79 + 3 Settings Groups as additional protection functions.


FTB/FTP Advantages

FANOX FTB/FTP test block allows testing the protection, control, metering and/or communication device of a facility connected to field switchgear, easily and safely, isolating the circuits fully and eliminating all risks for the user.

  • Maximum safety for the user.
  • Internal automatic CT short circuiting.
  • Single hand fully isolated plug.
  • Locking system for safest operation.
  • Possibility of horizontal or vertical mounting, respectively.