siemens
Siemens SIPROTEC 7SJ85 Motor Protection Relay
Model: 7SJ8511-5EB90-2FG0
4-hour response · Pricing in SAR · Delivery across all KSA regions
7SJ8511-5EB90-2FG0 — Siemens SIPROTEC 7SJ85 Motor Protection Relay
The Siemens SIPROTEC 7SJ85 is the comprehensive numerical motor protection relay for medium-voltage motors in Saudi Arabia's most demanding industrial environments — oil & gas processing, petrochemical plants, desalination facilities, and heavy industrial installations where motor failure causes significant production loss. The 7SJ85 consolidates in a single IED the full spectrum of motor protection functions that older installations required multiple discrete relays for: overcurrent (50/51), earth-fault (50N/51N), negative phase sequence (46), thermal overload model (49), locked rotor (48/14), undercurrent (37), broken conductor (46BC), and circuit breaker failure (50BF). This functional consolidation replaces a panel of six or more discrete relays with a single 4U 19-inch rack device, eliminating inter-relay wiring complexity and dramatically reducing commissioning time.
The 7SJ85's dual thermal image algorithm tracks stator and rotor thermal states simultaneously per IEC 60255-8 — the rotor typically reaches its thermal limit before the stator during locked rotor conditions, and the separate rotor image ensures the relay trips before rotor conductor damage occurs. Motor start supervision measures starting current magnitude and duration against the motor's speed-current envelope, detecting failed starts and generating detailed fault records for maintenance diagnosis. IEC 61850 Edition 2 GOOSE messaging sends trip signals to remote circuit breakers in under 5 ms, satisfying MV switchgear fast intertripping requirements. All 7SJ85 configuration uses DIGSI 5 software within the TIA Portal ecosystem.
In Saudi Arabia, the SIPROTEC 7SJ85 is the standard motor protection IED for ARAMCO's MV motor applications in the Eastern Province, SABIC's large MV process pump and compressor motors at Jubail Industrial City, SWCC's 6.6 kV and 11 kV desalination pump drives, and Ma'aden mining facility MV motors across the Kingdom.
Razz Middle East supplies SIPROTEC 7SJ85 relays with full DIGSI 5 engineering, factory acceptance testing, site commissioning, and secondary injection test support across Saudi Arabia.
Technical Specifications
Full specifications for the 7SJ8511-5EB90-2FG0
- Protection Functions
- 50/51 OC, 50N/51N EF, 46 NPS, 49 Thermal, 48/14 Locked Rotor, 37 Undercurrent, 46BC Broken Conductor, 50BF CB Fail
- Current Inputs
- 4 × CT
- Voltage Inputs
- 3 × VT (optional)
- Communication
- IEC 61850 Ed2, PROFINET, Modbus RTU
- GOOSE Trip
- <5 ms
- Software
- DIGSI 5
- Mounting
- 19" rack 4U
- Standard
- IEC 60255
Key Features & Benefits
- Dual thermal image algorithm tracks stator and rotor thermal state independently per IEC 60255-8 — the rotor image trips before rotor conductor damage during locked-rotor conditions, the most destructive failure mode for large MV motors.
- Motor start supervision measures starting current magnitude and duration against the motor's speed-current envelope, detecting failed starts and generating detailed fault records that maintenance teams use to diagnose causes.
- IEC 61850 Edition 2 GOOSE messaging sends trip signals to remote circuit breakers in under 5 ms, satisfying MV switchgear intertripping speed requirements without dedicated pilot wire cabling.
- DIGSI 5 configuration within TIA Portal ecosystem eliminates a separate relay engineering tool — Saudi automation engineers familiar with TIA Portal configure, test, and commission the 7SJ85 from the same platform.
- Broken conductor protection (46BC) detects an open phase caused by fuse failure or cable break before negative sequence current causes rotor heating damage — a protection function absent from most discrete relay schemes.
- Power quality measurement (V, I, P, Q, PF, energy kWh) provided without additional hardware, supporting ARAMCO and SABIC energy management reporting requirements from the protection relay itself.
- Secondary injection test mode allows functional testing of all protection functions during commissioning without running the motor, satisfying ARAMCO and SABIC relay testing procedure requirements.
Industrial Applications in Saudi Arabia
- MV motor protection at ARAMCO crude oil pump stations, gas compressor installations, and water injection pump facilities in the Eastern Province, protecting expensive 6.6 kV and 11 kV motors.
- SABIC petrochemical plant MV process pump and compressor motor protection at Jubail Industrial City, where IEC 61850 GOOSE enables fast bus-section interlocking in the event of a motor terminal fault.
- SWCC desalination plant 6.6 kV high-pressure pump motor protection, where the dual thermal image protects against stator and rotor damage during repeated stopping and starting cycles.
- Ma'aden mining facility MV ventilation fan and conveyor drive motor protection, where undercurrent detection identifies belt breakage before the motor trips on thermal overload.
- Large HVAC centrifugal chiller drive protection at district cooling plants, where the locked rotor function provides fast tripping preventing compressor winding damage during starting failures.
- Power plant auxiliary motor protection for feedwater pumps and forced draft fans, where 7SJ85 GOOSE intertripping with turbine protection enables fast plant trip sequences.
- Cement plant kiln drive and raw mill motor protection, where the thermal model is specifically calibrated for the extended start characteristic of ball mill and kiln motors.
Industrial Supplier in Saudi Arabia
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Frequently Asked Questions — 7SJ8511-5EB90-2FG0
Common questions from buyers in Saudi Arabia and the GCC