As the third installment in ABB's Relay Protection Series Collection, this edition focuses on the eight core product series most frequently used in daily operations: SPAJ140,601,611,615,620, REX640,650, and 670. For each series, we provide comprehensive coverage of its sub-models and functional positioning, offering a thorough overview—from product family, core features, and applicable scenarios to selection guidelines. We have also introduced three practical modules: common selection pitfalls, migration between legacy and new models, and a rapid decision tree, effectively addressing selection challenges. Engineers can now directly apply these insights to their work!
I. Overview of ABB Relay Protection Product Family
ABB relay protection is primarily divided into two major categories:
o• Classic cost-effective series: SPAJ series, designed primarily for replacement in existing markets and simple power distribution scenarios, with over one million units already in market circulation.
o• Next-generation Relion intelligent protection series: covering all application scenarios—from medium-and low-voltage power distribution and smart substations to high-voltage transmission and main equipment protection—while supporting IEC61850 intelligent communication; it has become the unequivocal mainstream choice for new projects built since 2015.
All products are categorized into large-scale product series; each series then gives rise to specialized variants tailored to different protection requirements—via distinct hardware configurations or software packages—thereby forming a comprehensive product portfolio. The following section provides an in-depth analysis of each series individually.
II. Detailed Selection Guidance for the 8 Core Product Series
1. SPAJ140 Series – Classic Cost-Effective Overcurrent Protection
o• Overall product positioning: ABB's time-tested and classic overcurrent and ground fault protection relays have remained stable for over 30 years, making them the preferred cost-effective solution for non-intelligent substations.
o• Core sub-models:
o• SPAJ140C: General-purpose overcurrent and ground protection; possesses the largest market share.
o• SPAJ140D: Enhanced model with automatic retriggering function
o• Core features: phase-to-phase overcurrent protection, zero-sequence overcurrent protection, inverse-time protection, reclosing function, and basic Modbus communication
o• Hardware features: compact design, simplified wiring, wide operating voltage range (AC 80–265 V / DC 18–80 V), exceptional stability, and outstanding cost-performance ratio
o• Applicable scenarios: 10 kV/35 kV conventional feeder protection, upgrading and retrofitting of legacy substations, simplified power distribution systems for industrial and mining enterprises, and cost-constrained non-intelligent power distribution projects.
o• Selection Recommendation: If only basic overcurrent and grounding protection is required, and there are no needs for intelligent communication, this model should be prioritized—it offers the optimal cost ratio and well-established operation and maintenance capabilities.
o• ⚠ Important Notice: The SPAJ140 has entered the end stage of its product lifecycle, and ABB has officially ceased production. Currently, the available market consists primarily of existing stock and second-hand equipment; therefore, its use in new projects is not recommended.
2. 601 Series: Entry-level Compact Feeder Protection
o• Overall Series Positioning: The Relion series offers entry-level basic feeder protection and minimalist distribution protection, specifically designed for compact space scenarios.
o• Core sub-models:
o• REF601: Feeder protection with circuit breaker control
o• REJ601: Pure overcurrent protection without circuit breaker control
o• REJ603: Self-powered feeder protection (no external auxiliary power required; power is derived from the CT)
o• Core Features: Basic overcurrent / ground fault protection, electrical parameter measurement, 4 configurable binary inputs, 6 output interfaces, and basic protocol communication
o• Hardware features: ultra-compact design (160×96×151.5 mm), suitable for compact installation spaces such as ring main units and box-type transformers
o•applicable scene:
o• REF601/REJ601: Small compact substations, ring main units, simple industrial power distribution systems, and rural low-voltage power distribution networks
o• REJ603: Distribution in remote areas without auxiliary power supply, outdoor ring main units, and unattended stations
o• Selection Recommendation: For new basic power distribution projects, where no complex logic is required and compactness and low cost are prioritized, REF601 is the preferred choice; if no auxiliary power supply is available, REJ603 must be selected.
3. 611 Series – High Value Basic Intelligent Protection (Official replacement for 610)
o• Overall positioning of the series: The Relion series offers fundamental intelligent protection and serves as the official direct successor to the 610 series. Positioned between the 601 and 615 series, it emphasizes intelligent features and cost-effectiveness.
o• Core sub-models and their corresponding protected objects:
o• REF611: Basic feeder protection
o• REM611: Basic Motor Protection
o• Core Features: Basic overcurrent/grounding protection, electrical parameter measurement, basic measurement and control, and support for basic communication according to IEC61850 Ed2
o• Key differences from 615: does not support GOOSE/SV sampling value communication, does not support PRP/HSR redundant networks, has fewer I/O points, and offers shorter fault recording duration (maximum 100 s)
o• Hardware features: Same chassis size as the 615, compatible terminal blocks, and supports direct upgrade to the 615 in the future.
o• Applicable scenarios: cost-sensitive projects requiring basic IEC61850 communication, rural smart grids, small-scale industrial power distribution, and non-critical load protection.
4. 615 Series All-in-One Core Protection (Best-Selling Model)
o• Overall Series Positioning: The best-selling model in the Relion series—a versatile standard configuration for medium-voltage intelligent substations, covering 90% of medium-voltage application scenarios; it is the preferred choice for newly built intelligent substations.
o• Complete list of sub-models and their corresponding protected objects:
o• REF615: Dedicated feeder protection (supports arc flash protection, fault location, and DG grid integration)
o• RET615: Protection for small and medium-sized transformers (differential, non-electrical, and integrated backup protection)
o• REG615: Protection for small and medium-sized generators (comprehensive protection against loss of excitation, loss of synchronization, and islanding)
o• RED615: Medium-voltage line differential protection
o• REB615: Medium-voltage busbar protection
o• REU615: Voltage Transformer Protection
o• REV615: Capacitor Protection
o• Key advantages: full-featured configuration, IEC61850 Ed2 compliance, GOOSE/SV communication, PRP/HSR redundant network, and compatibility with multiple protocols including Modbus, DNP3, and IEC60870-5-103
o• Applicable scenarios: 10 kV–35 kV smart substations, industrial high-voltage distribution systems, wind power / photovoltaic step-up substations, and primary transformer / generator unit foundation protection
o• Selection Recommendation: For new smart substations, this model is the preferred choice in 90% of medium-voltage scenarios—offering single-unit compatibility, exceptional versatility, and streamlined operation and maintenance.
o• ⚠ Important Notice: The 615 series is available in multiple hardware versions (Version A, Version B, and Version C). Software for different versions is not compatible; please verify the hardware version when making a purchase.
5. 620 Series High-Performance Feeder / Transformer Protection
o• Overall product positioning: High-performance protection solutions for high-voltage medium-voltage power distribution; the 615 series features an upgraded functional configuration, designed for complex network environments and high-demand application scenarios.
o• Core sub-models:
o• REF620: Complex feeder protection, compatible with ring networks, multi-power grid integration, and long-distance fault recording
o• RET620: Protection solution for medium-and large-sized transformers, featuring integrated differential, backup, and measurement/control functions, with refined protection logic.
o• Key advantages: high I/O capacity, advanced algorithms, extended recording duration (up to 1,000 s), programmable complex logic, and support for high-penetration distributed power supply scenarios
o• Applicable scenarios: large-scale distribution substations, industrial parks, centralized new energy step-up substations, and complex distribution networks
o• Selection recommendation: For distribution networks with complex topologies and highly refined protection requirements, where the 615 functionality is insufficient, directly upgrade to the 620 model.
6. REX640 – High-end all-in-one protection
Note: The model "REF640" does not exist; the correct official model number is "REX640".
o• Product Positioning: The Relion series—high-end modular all-in-one protection devices—provides dedicated protection for primary equipment, enabling one unit to protect multiple units.
o• Key Features: A single hardware model; all functionalities are achieved by selecting different software packages; flexible full-lifecycle upgrades; and the ability to extend functionality without replacing the hardware.
o• Primary software packages and their corresponding protected objects:
o• Feeder protection package: high-voltage feeders and incoming line protection
o• Transformer protection package: protection for large three-winding transformers and autotransformers
o• Generator Protection Package: Protection for medium-and large-sized generator sets
o• Busbar Protection Package: Medium-and High-Voltage Busbar Protection
o• Motor Protection Kit: High-Voltage Motor Protection
o• Capacitor protection kit: parallel capacitor bank protection
o• Key advantages: integrated design, high reliability, compatibility with high voltage levels, and protection for complex main equipment
o• Applicable scenarios: 110 kV and below substations, protection of large main transformers, large and medium-sized generator sets, and high-end industrial power distribution systems
o• Selection Recommendations: One-stop comprehensive equipment selection for protection of large main transformers, critical units, and high-voltage-rated main equipment.
7. 650 Series High-Voltage Transmission / Main Equipment Protection
o• Overall product positioning: specialized protection for high-voltage transmission lines and primary equipment, and core devices for hub substations
o• Core sub-models:
o• REF650: Distance Protection for High-Voltage Transmission Lines and Regional Stability Control
o• RET650: Protection for large 110 kV–220 kV transformers
o• REG650: Protection for large generators
o• Core functions: high-voltage line distance protection, zero-sequence protection, overcurrent protection, regional stability control logic, and synchronous sampling
o• Applicable scenarios: 110 kV–500 kV high-voltage transmission lines, regional power grid stability control, and protection of main equipment in hub substations
o• Selection Recommendation: Integrated main and backup protection for high-voltage transmission lines and grid stability control—dedicated equipment selection
8. 670 Series Ultra-High Voltage Line / Main Equipment Protection
o• Overall product positioning: dedicated protection for ultra-high voltage (UHV) and extra-high voltage (UHV+) transmission lines and their primary equipment, as well as core protection for power grid trunk lines.
o• Core sub-models:
o• RED670: Ultra-high voltage line fiber optic differential primary protection
o• RET670: Protection for ultra-large 220 kV–500 kV transformers
o• REG670: Protection for million-kilowatt class generator sets
o• Core functions: current differential protection, weak power supply-side adaptation, channel monitoring, fault recording, and high-speed operation (operation time <10 ms)
o• Applicable scenarios: 220 kV and above ultra-high voltage interconnection lines, critical long-distance transmission lines, core grid trunk lines, and main equipment of large power plants
o• Selection recommendation: Primary protection for ultra-high voltage / extra-high voltage lines; dedicated differential protection devices are preferred.
