Fanox SIA-B Specific CTs – Dual & Self-Powered Overcurrent Protection Relay

Fanox SIA-B Specific CTs — Dual & Self-Powered MV Protection Relay

The SIA-B Specific CTs variant is designed for installations with specific (non-standard) current transformers, offering a higher saturation level and broader measurement range versus standard CTs. It self-starts from 0.4 × the minimum CT primary current (three-phase), making it suitable for low-load or rural MV feeders.

Key Features

• Self-powered via three specific CTs (higher saturation level vs standard CTs)
• Start-up at 0.4 × Is min (3-phase)
• Auxiliary supply: 24–230 V AC/DC; USB cable / power bank support
• Optional internal battery for commissioning without energised line
• 0.5 W consumption (ultra-low for extended battery backup)
• 100 event records, 4 fault reports; 20×2 LCD + 7/8 keys HMI
• Trip output: 24 Vdc – 135 mJ for striker actuation
• Compact vertical (120.65×167.80 mm) or horizontal (185.80×102.7 mm) form factor
• KEMA certified; RS485 Modbus RTU communication

ANSI Protection Functions

50 (instantaneous overcurrent), 51 (inverse-time overcurrent), 50N/51N (calculated neutral), SHB (second harmonic blocking), 49 (thermal overload), 49T (external trip), TB (trip block), PGC (programmable logic).