Description
The ABB RXDSC 4 (incorporating part number 1MRK000344-A) is a numerical protection relay designed for industrial and utility electrical power systems. It provides reliable overcurrent and earth-fault protection functions to safeguard distribution networks, transformers, and electrical feeders against abnormal operating conditions.
| Parameter | Specification |
| Brand | ABB |
| Model | RXDSC 4 |
| Part Number | 1MRK000344-A |
| Series | RXD Modular Protection and Control Series |
| Product Name | Numerical Overcurrent & Earth-Fault Relay |
| Place of Origin | Sweden / Switzerland / Global Manufacturing |
| Product Status | Mature / Legacy Industrial Support |
| Dimensions | Standard COMBIFLEX modular terminal/case mounting format |
| Weight | Approx. 2.5 kg |
| Country of Origin | Sweden |
| Power Consumption | Low-voltage industrial DC auxiliary power supply |
First-Run Inspection Checklist
- ☑ Physical Integrity Check
Inspect the outer relay housing, plug-in connection pins, front-panel indicators, and terminal blocks for any physical transport damage, cracks, or loose components.
- ☑ Auxiliary Power & Grounding Verification
Verify that the incoming auxiliary control voltage matches the relay nameplate rating using a calibrated multimeter prior to energization. Ensure the module enclosure is securely connected to the system protective earth.
- ☑ Hardware & Setting Configuration
Confirm that the internal relay settings, CT/VT ratio configurations, and protection parameters match the electrical network coordination study and plant documentation before commissioning.
Routine Maintenance & Servicing
- 🛠 Environmental Monitoring
Regularly check switchgear compartment climate controls to maintain ambient operating temperatures within recommended industrial limits and prevent excessive dust or moisture accumulation.
- 🔌 Terminal & Wiring Inspection
Perform periodic visual checks on current transformer secondary wiring blocks and control terminal screws to ensure firm mechanical connection and absence of vibration-induced loosening.
Troubleshooting & Common Issues
- ⚠️ Auxiliary Power Failure or Blank Display
If the unit fails to power up or indicators remain inactive, check incoming auxiliary supply fuses, measure terminal voltage levels, and inspect internal power supply module connections.
- ⚠️ Spurious Overcurrent Tripping
If unexpected protection trips occur, review event logs or fault indicators, and check load current measurements against configured pickup thresholds.
Safety Precautions
- 🔐 Electrostatic Discharge (ESD) Protection
Always wear a grounded ESD wrist strap and follow standard antistatic protocols when handling internal modules or conducting maintenance to protect sensitive static-sensitive integrated circuits.
- ⚠️ Current Transformer (CT) Safety
Never open-circuit secondary terminals of live current transformers while the primary network circuit is energized. Always short-circuit CT secondary windings before disconnecting input wiring to prevent dangerous high-voltage induction.
Frequently Asked Questions (Q&A)
- ❓ Q1: What is the primary function of the ABB RXDSC 4 relay?
A: The RXDSC 4 functions as a numerical protection relay engineered to provide selective overcurrent and earth-fault protection for electrical distribution systems and apparatus.
- ❓ Q2: What precautions should be observed when servicing COMBIFLEX-based modular relays?
A: Ensure that control power and CT circuits are safely isolated, use proper insertion/extraction tools if applicable, and verify that module identification and part numbers match replacement requirements precisely.
