Description

Application Scenarios:

In a crucial 220/66 kV grid transmission substation, a 100 MVA power transformer is the vital link between the high-voltage grid and a major metropolitan area. A developing inter-turn fault inside the transformer creates a complex electrical signature that standard overcurrent relays may not detect until significant damage occurs. The ABB RET670 1MRK002816-AA acts as the transformer’s dedicated protection system. In this scenario, the relay’s sophisticated algorithms continuously analyze the high-resolution current signals from both the HV and LV windings, as well as the neutral. Its core transformer differential protection function precisely calculates the current imbalance, identifying the small but dangerous internal fault within milliseconds. Simultaneously, its restricted earth fault protection provides sensitive grounding protection. The RET670 1MRK002816-AA issues a trip command to the main circuit breakers, isolating the transformer before the fault escalates into a catastrophic failure. This action prevents a potential city-wide blackout, protects a multi-million dollar asset, and ensures grid stability, showcasing its role in preventing widespread, long-duration outages.

Parameter:

Main Parameters	Value/Description
Product Model/Order Code	RET670 1MRK002816-AA
Manufacturer	ABB / Hitachi Energy
Product Category	Numerical Transformer & Bay Control Relay (IED)
Primary Protection Functions	Transformer Differential, Restricted Earth Fault, Overcurrent, Overload, Overvoltage/Undervoltage, Breaker Failure, etc.
Control Functions	Bay control, sequence control, interlocking, synchrocheck.
Inputs / Outputs	Analog: Up to 12 CT/VT inputs. Digital: Multiple BI/BO. [Configurable]
Communication Protocols	IEC 61850 (MMS & GOOSE), IEC 60870-5-103/104, Modbus, DNP3. [Core for modern substations]
Operating Time (Differential)	< 25 ms (typically) for internal faults.
Power Supply	24-250 VDC / 110-240 VAC (Wide range).
HMI Interface	Large graphical LCD, keypad, LED indicators.
Standards Compliance	IEC 60255, IEC 61850, IEEE C37.90.
Primary Application	Protection, control, and monitoring of 2- or 3-winding power transformers.

Technical Principles and Innovative Values:

The RET670 1MRK002816-AA is a complete bay computer, integrating multiple disciplines into a single, powerful platform.

Innovation Point 1: Advanced, Adaptive Transformer Differential Protection: The relay employs a high-impedance, percentage-restrained differential algorithm. It is inherently stable during external faults, magnetizing inrush, and overexcitation conditions, preventing nuisance trips. It includes advanced harmonic restraint (2nd harmonic for inrush, 5th harmonic for overexcitation) and can be configured for various transformer vector groups, winding connections (Wye/Delta), and tap-changer positions, providing unmatched accuracy for internal fault detection.
Innovation Point 2: True IEC 61850 System Integration: The RET670 1MRK002816-AA is designed as a native IEC 61850 device. It supports both MMS for SCADA communication and, critically, high-speed GOOSE (Generic Object-Oriented Substation Event) messaging. This allows the relay to send trip commands and receive interlocking signals from other IEDs (like busbar or feeder relays) over the substation LAN in 2-4 ms, enabling complex, fast-acting protection schemes like busbar or breaker failure protection without hardwired connections.
Innovation Point 3: Integrated Condition Monitoring and Advanced Metering: Beyond protection, the RET670 1MRK002816-AA acts as a data hub. It provides high-accuracy energy metering (kWh, kVARh), detailed power quality monitoring (harmonics, flicker), and transformer condition monitoring. It can calculate transformer thermal capacity (based on measured current and ambient temperature), estimate oil/winding temperature, and issue alarms for incipient problems, enabling a shift from periodic to condition-based maintenance.