The GEC Alsthom MFVU21D1CA0005B is a high-precision, microprocessor-based protection relay from the MFVU family, designed specifically for voltage and frequency monitoring. This relay plays a critical role in maintaining the stability of power systems by detecting abnormal frequency or voltage conditions that could lead to equipment damage or grid instability. It is an essential safeguard for power generators, industrial networks, and sensitive electrical loads.

 

Product Datasheet & Technical Specifications

The MFVU series combines digital accuracy with industrial-grade durability.

• Model Number: MFVU21D1CA0005B
• Relay Type: Under/Over Voltage and Under/Over Frequency Protection
• Measuring Elements: Dual-channel monitoring for comprehensive system oversight
• Frequency Range: Settings for 50Hz or 60Hz systems with high-resolution increments (typically 0.01Hz)
• Voltage Range: Wide adjustment range for both under-voltage and over-voltage thresholds
• Auxiliary Supply: 110V to 125V DC (standard for the “D” voltage code)
• Time Delay: Adjustable definite time delays to prevent nuisance tripping during transient fluctuations
• Case Type: Size 4 modular drawout case for easy maintenance

 

Country of Origin

This protection relay was manufactured in the United Kingdom (UK) at the Stafford site, upholding the engineering excellence associated with GEC Alsthom, Alstom, and AREVA.

 

Application Fields

The MFVU21D1CA0005B is widely used in power management and load shedding schemes:

• Load Shedding: Automatically disconnecting non-essential loads when the grid frequency drops below safe limits.
• Generator Protection: Safeguarding alternators against overspeed (over-frequency) or excitation failure.
• Islanded Operation: Managing the stability of microgrids or isolated industrial power systems.
• Inverter/Renewable Integration: Ensuring solar or wind farms stay within mandatory voltage and frequency windows for grid connection.
• Motor Protection: Preventing damage to large AC motors caused by sustained under-voltage conditions.

Product Instructions & Technical Notes

When commissioning the GEC Alsthom MFVU21D1CA0005B, verify that the auxiliary power supply matches the 110-125VDC rating to avoid damage to the internal power module. The relay utilizes digital logic for timing; therefore, ensure the “Time Delay” settings are coordinated with the upstream protection to avoid “race” conditions during system-wide disturbances. The drawout case allows for testing the relay without disturbing the panel wiring; however, always ensure the voltage transformer (VT) secondary fuses are intact before assuming a relay failure.

 

Q&A – Frequently Asked Questions

Q1: What does “21” in the MFVU21 model name signify? A: In the MFVU nomenclature, “21” typically indicates a dual-stage or dual-function measurement (e.g., combined voltage and frequency logic).

Q2: Can I use this relay for both 50Hz and 60Hz systems? A: Yes, the MFVU series is generally programmable or switchable between 50Hz and 60Hz, though you must verify the specific jumper or software settings upon installation.

Q3: How does the “Load Shedding” function work with this relay? A: The relay monitors the rate of frequency decay. If it falls below a set threshold, it triggers an output contact to trip a circuit breaker, reducing the total load on the generator to restore frequency balance.

Q4: Is this relay compatible with AREVA or Alstom systems? A: Yes, as GEC Alsthom evolved, the MFVU series was maintained across the Alstom and AREVA brands, ensuring complete hardware and software compatibility.

 

Similar Model Recommendations

1. GEC Alsthom MFVU11 (Single-stage version)
2. GEC Alsthom MAVW (Voltage and Frequency check relay)
3. Alstom MiCOM P12x (Modern digital overcurrent/voltage equivalent)
4. GEC Alsthom MVAA (Auxiliary trip relay)
5. GEC Alsthom VAVS (Voltage sensitive relay variant)