ABB SPAJ115C SPACOM | Combined Restricted & Residual Earth Fault Protection Relay In Stock

Description

At-A-Glance Executive Brief

• Model: SPAJ115C (SPACOM series)
• Brand: ABB
• Part Type: Combined restricted earth-fault (REF) and residual earth-fault protection relay
• Lifecycle status: OEM obsolete, discontinued in 2009; stocked for power plant & substation brownfield protection panels
• System compatibility: SPACOM fiber optic serial bus, interfaces with DCS/SCADA supervisory systems
• Weight: 1.1 kg

Technical Introduction

Loss of SPAJ115C protection removes sensitive stator/winding earth fault detection, risking severe permanent damage to generators, large motors or transformers during internal earth faults. The SPAJ115C belongs to ABB SPACOM digital protection relay family. It integrates two independent earth fault protection stages: fast selective restricted earth-fault differential protection and backup residual earth-fault protection with definite-time or inverse-time characteristics. It measures differential zero-sequence current and residual zero-sequence current from CT inputs. It features a local numeric display for measured values, settings and fault records, continuous hardware and software self-monitoring, plus fully configurable trip and signalling relay outputs. The fiber optic serial bus enables bidirectional communication to substation supervisory systems for remote readout, fault event logging and setting access. Power utilities and generation plants hold spare relays to reduce forced outage risk while planning legacy SPACOM protection migration.

• Best Suited For
  • Generator, large HV motor and transformer restricted earth fault protection
  • Medium voltage substation brownfield SPACOM protection cubicles
  • Direct drop-in replacement for existing SPAJ115C SPACOM protection relays

Core Technical Specifications

Field Engineer’s Tech Notes

• CT polarity is critical for REF operation. Reversed CT polarities cause false tripping or failure to operate during real winding earth faults.
• Relay settings must be fully backed up before replacement. A new spare unit is blank and requires full parameter upload before commissioning.
• CT secondary circuits carry hazardous current. Execute lockout/tagout and confirm zero energy before disconnecting CT wiring.

Adaptive QA & Testing Protocol

Each SPAJ115C relay is bench tested using secondary injection test equipment. We inject zero-sequence current to verify pickup thresholds and operating times for both restricted earth-fault and residual earth-fault stages. All trip and signalling relay outputs are validated. Local display readout and fault event recording functions are checked. Fiber serial communication handshake is verified with SPACOM bus interface hardware. Self-supervision diagnostics are tested under simulated hardware fault conditions. Full test reports or bench test video clips are available upon request.

Buyer’s FAQ

Q: What is SPAJ115C used for? A: It is a combined restricted earth fault and residual earth fault protection relay, designed to protect generator, large motor and transformer windings against internal earth faults in power plants and substations.

Q: What warranty applies for refurbished and NSFP SPAJ115C? A: Refurbished and NSFP units carry a 12-month hardware warranty. Coverage excludes damage from CT open-circuit transients, incorrect wiring or improper protection setting configuration.

Q: What lead time should I expect? A: Stocked units ship 3–7 business days. If inventory is depleted, lead time increases while we source surplus SPACOM SPAJ115C relays.

Q: What is the modern ABB replacement for SPAJ115C? A: ABB Relion REX615 is the recommended retrofit replacement for SPAJ115C REF protection applications, supporting modern communication protocols such as IEC 61850.