Product Overview
ABB SPAD 346 C2 is a legacy SPACOM‑family stabilized differential protection relay dedicated for two‑winding power transformers and generator‑transformer sets. It provides main differential protection for internal winding short‑circuits, inter‑turn faults and earth faults, together with multi‑stage overcurrent and earth‑fault backup protection. Second‑harmonic restraint prevents false tripping during transformer magnetizing inrush; fifth‑harmonic restraint avoids mal‑operation under transformer over‑excitation conditionsABB Group. The built‑in disturbance recorder captures fault waveforms for post‑fault analysis. Continuous hardware‑software self‑supervision triggers IRF fault alarm upon internal relay failure. Widely used as spare‑part replacement for substation maintenance and retrofit of legacy SPACOM‑based protection installationsABB Group.
Series
SPAD 346 C series belongs to ABB SPACOM legacy protection relay portfolio. Variants C1, C2, C3 differ in hardware revision and auxiliary‑supply configuration. This combined‑function differential relay integrates differential module, over‑current module, earth‑fault module and I/O logic in one unit. The SPAD 346 C product line is superseded by modern ABB REX series protection relays for new‑build substation projectsABB Group.
Product Features
‑ Stabilized percentage‑biased differential protection for two‑winding transformers and generator‑transformer unitsABB Group ‑ Second‑harmonic restraint blocks unwanted tripping during transformer magnetizing inrush ‑ Fifth‑harmonic restraint provides stability against transformer over‑excitation conditionsABB Group ‑ Three‑stage phase overcurrent protection and two‑stage non‑directional earth‑fault backup protection ‑ Built‑in circuit‑breaker failure protection with adjustable operate delay timeABB Group ‑ Integrated disturbance recorder for analog current waveforms and binary event recording ‑ Wide‑range digital CT‑ratio correction, no need for intermediate interposing CTs ‑ Four heavy‑duty trip‑output relays for breaker tripping; five signal‑output relays for alarm indicationABB Group ‑ Five programmable binary control inputs for external interlock signals ‑ IRF self‑supervision alarm relay for hardware‑software fault monitoring ‑ RS‑488 serial communication interface for remote parameter setting and fault‑data retrieval ‑ Front‑panel display for phase‑current and phase‑angle checking, local status indication ‑ Panel‑mount metal housing for standard substation control‑cabinet installation ‑ Direct drop‑in replacement for original SPAD 346 C2 hardware
Product Parameters
‑ Rated Current Input: 1 A or 5 A CT secondary ‑ Rated Frequency: 50 Hz / 60 Hz (order‑code dependent) ‑ Auxiliary Supply: 80‑265 V AC/DC or 18‑80 V DC (variant‑dependent) ‑ Communication: RS‑488 serial interface ‑ Trip Output Contacts: 4 heavy‑duty trip relays ‑ Signal Output Contacts: 5 signal‑alarm relays ‑ Binary Inputs: 5 programmable external control inputs ‑ Fault Recorder: Built‑in disturbance‑recording function ‑ Self‑supervision: IRF fault‑alarm relay ‑ Operating Temperature: ‑5 °C ~ +55 °C ‑ Storage Temperature: ‑25 °C ~ +70 °C ‑ Relative Humidity: 5‑95 %, non‑condensing ‑ Front‑panel Protection Rating: IP42 ‑ Mounting: Cabinet panel‑mount ‑ Approvals: CE compliant
Product Specifications
‑ Form Factor: Panel‑mount metal‑cased combined‑function protection relay ‑ Protection Functions: Stabilized differential protection, 3‑stage phase overcurrent, 2‑stage earth‑fault, breaker‑failure protection, phase‑discontinuity supervisioneero ‑ Restraint Features: 2nd‑harmonic inrush restraint, 5th‑harmonic over‑excitation restraint ‑ Local Operation: Front‑panel status display, LED fault indicators ‑ Termination: Detachable screw‑type terminal blocks for CT and control‑circuit wiring ‑ Cooling: Natural convection ‑ Compatibility: Two‑winding power transformers, generator‑transformer units in medium‑voltage substations ‑ Weight: Approx 6 kg ‑ Maintenance: Direct swap‑out spare unit for substation‑site relay‑repair work
Function
SPAD 346 C2 samples current signals from HV‑side and LV‑side current transformers. It calculates differential and restraint currents, executes percentage‑biased differential protection logic. Second‑harmonic and fifth‑harmonic restraint algorithms block mal‑tripping caused by magnetizing inrush and transformer over‑excitation. When internal transformer faults are detected, the relay activates heavy‑duty trip relays to open the circuit breaker. Multi‑stage over‑current and earth‑fault modules provide backup protection. The disturbance recorder captures pre‑fault and fault‑period waveforms for post‑incident analysis. IRF relay reports internal hardware or software failures. Relay settings, fault records and real‑time measured values can be accessed via RS‑488 serial link for remote‑supervision systemsABB Group.
Purpose
Provide main differential and backup protection for two‑winding power transformers and generator‑transformer sets within distribution and power‑plant substations. Replace defective SPAD 346 C2 relays to restore transformer‑protection functions. Used for spare‑part stocking and maintenance of legacy SPACOM‑relay‑based substation installations.
Application Fields
Medium‑voltage distribution substations, power‑plant main‑transformer and auxiliary‑transformer protection, industrial‑plant power‑system substations, generator‑transformer unit protection, legacy ABB SPACOM‑protection‑system maintenance and retrofit projectsABB Group.
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