The GEC Alsthom MVAP22D1AA0001B is a specialized auxiliary voltage relay from the Midos range, specifically designed for use in automatic reclosing and check-synchronizing schemes. This relay is a critical component in power distribution and transmission networks, where it is used to monitor busbar and line voltages to ensure that a circuit breaker only recloses under safe, synchronized conditions. It provides the “Dead Line/Live Bus” or “Dead Bus/Live Line” logic required for automated grid restoration after a transient fault.

Product Technical Description

The MVAP22 is a dual-element voltage sensing relay. It features two independent measuring elements that can be configured to detect various voltage states (Under/Overvoltage). The “D1AA” configuration denotes a specific hardware build that includes stabilized internal power circuits and high-speed electromagnetic output elements. The relay monitors the magnitude and phase relationship of two separate AC voltage inputs (typically from a Line VT and a Bus VT). It is housed in a standard Midos size 4 draw-out case, allowing for easy testing and rapid replacement without disturbing the panel’s permanent wiring.

 

Product Datasheet & Parameters

• Model Number: MVAP22D1AA0001B
• Series: MVAP (Midos Voltage Auxiliary)
• Relay Type: Dual-Element Voltage Check / Autoreclose Logic
• Rated Voltage (Un): 110V AC (Standard VT secondary)
• Frequency: 50Hz / 60Hz (Universal)
• Auxiliary Supply (Vx): 24V – 125V DC (Wide-range)
• Setting Range: 10V to 120V (Adjustable for Dead/Live thresholds)
• Contacts: 4 Normally Open (NO) / 4 Normally Closed (NC) or mixed (Model dependent)
• Enclosure: Midos Size 4 draw-out vertical case
• Operating Time: Typically <30ms for high-speed logic execution

 

Country of Origin

This protection relay was manufactured by GEC Alsthom (later Alstom/Areva) in the United Kingdom (Stafford, UK).

 

Application Fields

• Autoreclose Schemes: Providing the “Voltage Check” permissive signal for 110kV/220kV breakers.
• Check Synchronizing: Ensuring two parts of a grid are within voltage limits before closing a tie-breaker.
• Substation Automation: Logic interface for “Dead Line” charging and “Live Bus” synchronization.
• Industrial Microgrids: Managing the reconnection of local generation to the main utility grid.
• Feeder Automation: Automating the restoration of power in rural distribution networks after lightning strikes.

 

Product Usage Instructions

Install the MVAP22 in a vertical position within the protection cubicle to ensure proper mechanical operation of the internal elements. Connect the Line VT to one element and the Bus VT to the second. Use the front-panel potentiometers to set the “Live” threshold (typically 80% of Un) and the “Dead” threshold (typically 20% of Un). During commissioning, use a dual-channel voltage injection set to verify the logic: the relay should only provide a “Close” command when the programmed conditions (e.g., Dead Line AND Live Bus) are met. The draw-out module features integrated CT shorting links, although voltage circuits should always be isolated before removal to prevent unintended logic trips.

 

Common Questions & Answers (Q&A)

Q: Can this relay perform full synchronization (matching frequency and phase)? A: No. The MVAP22 is a voltage check relay. It verifies that the voltages are present or absent as required. For full frequency and phase angle matching, a synchronizing relay like the SKD or MiCOM P40 series is required.

Q: What is the purpose of the dual elements in the MVAP22? A: The two elements allow the relay to simultaneously monitor two different voltage sources (e.g., the Line and the Bus) to determine if it is safe to close the breaker.

Q: Does the relay indicate which element has operated? A: Yes, the front panel typically features two mechanical flags or LED indicators that show the status of Element 1 and Element 2 independently.

Q: Is the auxiliary DC supply necessary for operation? A: Yes. Unlike some electromechanical relays, the MVAP series requires a stable auxiliary DC supply to power its internal logic and output relays.

 

Similar Model Recommendations

1. GEC Alsthom MVAP01 (Single-element version)
2. GEC Alsthom MVAP21 (Variation in contact arrangement)
3. Alstom MiCOM P921/P922 (Modern digital voltage relays)
4. GEC Alsthom SKD series (Check synchronizing)
5. GEC Alsthom VATT series (Voltage/Frequency)