ALSTOM 029.147.908 Transformer Protection Relay

The ALSTOM 029.147.908 is a dedicated numerical protection relay for two‑winding power transformers. It combines high‑speed differential protection with comprehensive backup overcurrent and earth fault functions, ensuring fast and selective fault clearance for transformers in utility and industrial applications.

Key Features

• Percentage differential protection (87T) with harmonic restraint for inrush detection

• Restricted earth fault protection (64REF) for sensitive winding fault detection

• Overcurrent, earth fault, and negative sequence overcurrent (50/51/51N/46)

• Overfluxing protection (24) and thermal overload (49)

• Automatic CT ratio and vector group matching

• Five sets of protection settings for different transformer configurations

• Event and fault records with 1 ms time stamping

Technical Specifications

• Rated currents: 1 A or 5 A for both HV and LV sides

• Differential current accuracy: ±2% or 20 mA (whichever greater)

• Harmonic restraint: 2nd and 5th harmonics with adjustable thresholds

• Binary inputs: 12 (24‑220 V DC)

• Output relays: 8 (trip, alarm, control)

• Communication protocols: IEC 61850, Modbus, DNP3, IEC 60870‑5‑103

• Power supply: 24‑250 V DC / 100‑240 V AC

• Operating temperature: -25°C to +70°C

Applications

The 029.147.908 is suitable for protection of distribution and power transformers up to 100 MVA. It can be applied in utility substations, industrial power systems, and renewable energy plants where transformer protection is critical. The relay also provides monitoring of transformer condition through harmonic analysis and tap position input.

User Interface and Configuration

The relay features a large graphical display showing single‑line diagrams, phasors, and harmonic content. Setting groups can be switched remotely or locally to adapt to different operating conditions. The embedded web server and IEC 61850 interface enable easy integration with station HMI and SCADA.

With its robust design and proven algorithms, the ALSTOM 029.147.908 ensures reliable transformer protection, minimizing damage and outage time.