Omicron CMA 156 6-Phase Current Amplifier Relay TestSet

The Omicron CMA 156 is a 6-phase current amplifier that extends the capabilities of OMICRON CMC test sets and integrates with digital real-time power system network simulators. The unit delivers six independent current channels organized into two galvanically isolated groups (A and B), enabling flexible output configurations for multi-phase relay testing, overcurrent protection relays, differential relays, and distance relays. Outputs support parallel and series connection topologies to achieve higher current or power delivery. The CMA 156 provides real-time monitoring of current output parameters with a flexible control interface for rapid configuration of current levels, phase shifts, and test parameters. Its compact, portable design suits field deployment.

– Technical Specifications

Current Amplifiers
• 6-phase AC (L-N): 6 × 0 to 25 A
• 3-phase AC (L-N): 3 × 0 to 50 A (Group A II B)
• 1-phase AC (L-N): 1 × 0 to 150 A (Group A II B)
• DC (L-N): 2 × 0 to ±25 A / 1 × 0 to ±50 A

Power Output
• 6-phase AC (L-N): 6 × 70 VA at 7.5 A
• 3-phase AC (L-N): 3 × 140 VA at 15 A (Group A II B)
• 1-phase AC (3L-N): 1 × 420 VA at 22.5 A; 1 × 420 VA at 45 A (Group A II B)
• 1-phase AC (L-L): 1 × 280 VA at 7.5 A
• DC (L-N): 2 × 140 W at ±10.5 A; 1 × 280 W at ±21 A (Group A II B)

Amplifier Performance
• Input Impedance: > 40 kΩ
• Galvanic Isolation (Input/Output): 1.5 kVDC
• Accuracy Error: < 0.03% typical, < 0.1% guaranteed
• THD+N: < 0.1% typical, 8 kHz
• Phase Lag: 1.07° / 1.28° at 50/60 Hz (typ.)
• Input Voltage: 0 to 5 Vrms
• Amplification: 5 A / V
• Max. Compliance Voltage (L-N)/(L-L): 15 Vpk / 60 Vpk

– Key Features

• Fully overload and short-circuit protected on all current and voltage outputs
• Protected against external high-voltage transient signals and overtemperature conditions
• Hardware self-diagnostics executed at each startup
• Configurable outputs supporting parallel and series connection topologies
• Parallel connection of all six phases yields up to 420 VA and 150 A; four CMA 156 units can generate 3 × 200 A

– Typical Applications

• Multi-phase relay testing and validation
• Overcurrent relay characterization
• Differential relay commissioning
• Distance relay performance assessment
• Field-based protection system testing

– Compatibility & Integration

Connects to OMICRON CMC test sets via control cable interface.