Description

Application Scenarios

In a large chemical plant, the continuous operation of a 6.6kV medium-voltage feeder supplying a critical production line is paramount. A phase-to-phase fault caused by insulation degradation in a motor cable could cascade into a plant-wide outage, costing millions in lost production. The ABB REF615 Feeder Protection Relay is installed as the main protection unit on this feeder. It continuously monitors three-phase currents, voltages, and calculates derived values. Within 20-30 milliseconds of the fault inception, its advanced differential or overcurrent protection function detects the abnormal condition, precisely determines it is within its designated protection zone, and issues a trip command to the circuit breaker. Simultaneously, it records detailed oscillography and event data. This immediate, selective isolation confines the fault to a single feeder, allowing the rest of the plant to continue operation and enabling maintenance crews to locate and repair the fault swiftly using the relay’s precise fault location data. The REF615 directly addresses the core pain points of selective coordination, fault analysis, and minimizing outage impact.

Parameter

Main Parameters	Value/Description
Product Model	ABB REF615 Feeder Protection Relay
Manufacturer	ABB (Asea Brown Boveri)
Product Category	Numerical Feeder Protection Relay / Intelligent Electronic Device (IED)
Primary Protection Functions	Directional/non-directional overcurrent (50/51, 67), Earth-fault (50N/51N, 67N), Thermal overload (49), Two-step phase undervoltage (27), Autorecloser (79) [Core fault detection and isolation logic]
Control & Monitoring	Circuit breaker control, 8 configurable programmable LEDs, 5 configurable pushbuttons, Measurement of I, V, P, Q, PF, energy, etc.
Communication Protocols	IEC 61850 (Edition 1 & 2), Modbus RTU, DNP3, IEC 60870-5-103 [Ensures interoperability with modern SCADA and substation systems]
HMI Interface	Large graphical LCD with local/remote control capability, multilingual menu
Inputs/Outputs	Up to 9 binary inputs, 6 programmable outputs (relay contacts), Analog inputs for 3I + 3U (1A/5A, 100-120V)
Operating Power Supply	24-48V DC / 48-110V DC / 110-250V DC / 110-240V AC
Operating Temperature	-25°C to +55°C (-13°F to 131°F) for reliable operation in harsh substation environments
Certifications	IEC 60255, IEEE C37.90, UL, CE, DNV GL for marine applications
Primary Applications	Utility and industrial MV feeders, Transformer in-feed protection, MV motor protection, Busbar section protection

Technical Principles and Innovative Values

The ABB REF615 is built on a powerful microprocessor platform, utilizing advanced algorithms to move beyond simple threshold-based protection towards adaptive, condition-aware system security.

Innovation Point 1: Adaptive Protection with Load Encroachment and Voltage Dependant Features. Unlike traditional overcurrent relays, the REF615 incorporates logic to distinguish between a genuine fault and a high-load condition. Its load encroachment function adapts the protection characteristic based on actual load current, preventing nuisance tripping during legitimate startup or overload scenarios. Similarly, its voltage-dependent overcurrent protection increases sensitivity during voltage dips (when fault currents may be lower), ensuring reliable operation under all system conditions. This intelligence enhances security (no false trips) while maintaining dependability (tripping when required).
Innovation Point 2: Integrated IEC 61850 Communication for Process Bus Readiness. The relay is natively equipped with IEC 61850, the global standard for substation communication. It supports both station-level (GOOSE for inter-relay tripping, MMS for SCADA) and, in capable versions, process-level (Sampled Values) communication. This allows the REF615 to participate in a fully digital substation, replacing hardwired tripping circuits with high-speed, reliable GOOSE messages and receiving digitized current/voltage data via fiber optics, drastically reducing wiring, testing time, and CT saturation issues.
Innovation Point 3: Advanced Condition Monitoring and Detailed Event Analysis. The ABB REF615 functions as a data hub. It continuously monitors and logs key parameters like circuit breaker wear (operation counts, tripping current), thermal capacity used on cables/transformers, and power quality data (THD). When an event occurs, it captures detailed oscillographic records (pre- and post-fault waveforms) and a time-synchronized sequence of events (SOE). This rich diagnostic data, accessible locally or remotely, transforms fault analysis from a guessing game into a precise forensic exercise, enabling root cause analysis and predictive maintenance.