Component Snapshot At-a-Glance

• Model: MVAJ13D1GB0780A
• Manufacturer: GEC ALSTHOM (later AREVA, GE Vernova Grid)
• Alt P/N: MVAJ13B1GB0780A (High-burden coil variant, incompatible coil impedance); MVAJ23 series (larger multi-contact frame, cannot direct swap)
• Product Series: MVAJ13 compact hinged armature tripping relay, Midos standard draw-out rack form factor
• Hardware Type: Draw-out plug-in electromechanical auxiliary trip relay, transparent front protective cover, compact small footprint cabinet unit
• Key Feature: D-series low-burden DC coil, ultra-fast <15ms operate speed, multi-pole volt-free changeover contacts, Midos rack CT short-circuit safety terminals, no mechanical latching flag (self-reset design)
• Primary Field Use: Interface numerical protection relays (MCGG52 series) to medium voltage breaker trip coils; implement multi-circuit alarm signaling, intertrip logic and fault indication in power plant, refinery substation protection panels.

Hard-Numbers: Technical Specifications

• Protocol Support: Pure electromechanical device, no digital communication; dry volt-free contact outputs only
• Coil Nominal Rating: 110/125 VDC low-burden DC control supply (D suffix defines low-wattage coil winding)
• Operating Speed: Total operate time ≤15ms at rated DC voltage
• Reset Type: Electrical self-reset (no hand-reset mechanical trip flag; contacts revert automatically once coil de-energized)
• Contact Configuration: 3 sets of complete changeover (C/O) silver alloy contact stacks
• Contact Ratings (Resistive & Inductive):
  • Continuous carry: 5A @250VAC / 300VDC
  • 3-second fault make/carry: 30A peak, 7500VA AC / 7500W DC
  • Breaking capacity: 5A AC / 50W inductive DC (magnetic blowout arc suppression built-in)
• Coil Burden: Low-burden design, minimal DC battery draw; stable operation down to 50% nominal control voltage
• Operating Temperature: -10°C ~ +55°C cabinet operational; -40°C ~ +85°C storage
• Dielectric Isolation: 2000Vrms withstand between coil circuit and contact terminal wiring
• Mounting: Standard Midos draw-out rack, rear screw terminal wiring; integrated CT short-circuit jumpers on rack base for safe relay removal
• IP Rating: IP40 front cabinet dust protection
• Physical Weight: ~0.35kg compact unit
• Certifications: IEC 60255 power protection relay standard, CE Class B EMC for substation high-EMI environments

The Real-World Problem It Solves

High-burden MVAJ13B coils draw heavy DC current during simultaneous multi-feeder faults; station battery voltage collapses, protection trip commands fail to actuate breakers. MVAJ13D low-burden winding minimizes DC load, maintaining reliable pickup under severe bus fault voltage sag.Separate discrete auxiliary contact blocks waste limited rack space and add dozens of wiring splices; cabinet vibration creates intermittent open trip circuits during plant load transients.Large MVAJ23 high-contact count relays occupy double the rack slot width; compact MVAJ13D fits dense multi-relay protection panels without layout rework.Without built-in magnetic blowout contact arc suppression, inductive breaker trip coil back EMF welds standard small auxiliary relay contacts closed, creating permanent trip lockout failure.Self-reset design eliminates manual flag reset work for non-critical alarm/intertrip schemes, reducing operator outage recovery time.Where you’ll typically find it:

• Fossil power plant MV auxiliary feeder protection panels for overcurrent/earth fault alarm signalling
• Refinery petrochemical substation MCC medium voltage motor backup protection intertrip logic
• Urban distribution substation ring main unit remote SCADA fault indication circuits
• Small generator auxiliary protection panels for stator overload non-latching alarm outputs

This compact low-burden trip relay consolidates multi-circuit alarm and intertrip functions into a narrow draw-out unit, prevents DC battery voltage collapse during mass faults, and provides reliable inductive breaker coil switching with arc-resistant heavy-duty contacts.

Hardware Architecture & Under-the-Hood Logic

This hinged armature electromagnetic relay relies on lightweight low-impedance coil winding for fast, low-power operation, no mechanical latching mechanism.

1. 110/125VDC low-burden coil energizes internal lightweight magnetic armature when protection relay fault contact closes.
2. Armature pulls 3 independent C/O contact stacks simultaneously in ≤15ms, switching breaker trip coils and multi-channel fault alarm circuits.
3. Magnetic blowout metal plates integrated beside contact tips extinguish inductive DC arcs, preventing contact welding from trip coil back EMF.
4. Low-wattage coil winding draws minimal DC current, avoiding station battery voltage drop during concurrent multiple feeder fault trips.
5. Rear Midos rack terminal base includes factory CT short-circuit jumpers; safe relay withdrawal without dangerous open CT secondary kilovolt surge.
6. Silver alloy contact tips resist arc erosion from frequent fault cycling; self-reset design returns contacts to normal state immediately after coil de-energization.

Field Service Pitfalls: What Rookies Get Wrong

Substituting High-Burden MVAJ13B Variant For MVAJ13D Low-Burden Unit

New techs install MVAJ13B high-burden spare relays to cut inventory cost. During multi-feeder simultaneous faults, station DC battery voltage sags severely; high-burden coil fails to pick up, breakers do not trip, leading to transformer/motor winding catastrophic damage.Field Rule: Match full part suffix MVAJ13D1GB0780A low-burden coil for all multi-relay dense protection panels; segregate D low-burden / B high-burden MVAJ13 spares in labeled storage bins.

Forgetting CT Shorting Jumpers Before Withdrawing Draw-out Relay

Apprentices pull relay chassis without installing rack CT short links. Open CT secondary generates lethal kilovolt surge, damaging upstream MCGG52 protection relay sampling hardware and creating cabinet shock hazard.Quick Fix: Always fit factory CT short-circuit jumpers to rack terminal block before removing any Midos draw-out protection relay.

Over-Torquing Rear Terminal Wiring Screws

Crews over-tighten terminal lugs past factory torque spec, cracking relay rear PCB terminal tracks. Vibration induces intermittent open trip circuits that only fail during high plant load transients.Field Rule: Torque rear screw terminals to 0.7 N·m; retorque all MVAJ relay terminals during annual substation maintenance outage.

Deploying MVAJ13D Hand Reset MVAJ23 For Non-Latching Alarm Schemes

Technicians swap hand-latching MVAJ23 relays into alarm signal circuits. Latched mechanical flag blocks subsequent fault alarm signaling until manual reset, hiding sequential equipment faults from operators.Field Rule: Use self-reset MVAJ13D exclusively for non-latching alarm, indication and intertrip logic; reserve hand-reset MVAJ23 for critical breaker lockout schemes requiring manual reset after trip.

Commercial Availability & Pricing Note

Please note: The listed price is for reference only and is not binding. Final pricing and terms are subject to negotiation based on market stock, equipment condition (new/refurbished) and order quantity.