ABB REF620E_F NBFNAAAANDA1BNN1XF Protective Relay Module

I. Overview

As an intelligent relay protection device specially designed for medium and low voltage transformers, ABB REF615C_E belongs to ABB's advanced power protection and control product family and is a key line of defense to ensure the safe operation of transformers.

II. Technical Parameters

(I) Electrical Parameters

• Rated Voltage: Adapts to a wide voltage range, supporting a rated operating voltage of 100-250V AC/DC. It can flexibly meet the power supply needs of different power systems, whether it is the common AC power supply in industrial fields or the DC power supply in some special scenarios, it can work stably, enhancing the versatility and adaptability of the equipment.

• Rated Current: The primary rated current can be configured according to actual needs, usually supporting current transformer inputs from 1A to 5A. It meets the current monitoring requirements of transformers with different capacities, ensuring accurate collection of current signals during normal operation and fault conditions of the transformer, providing reliable data for the realization of protection functions.

• Frequency Range: The operating frequency range is 45-65Hz, compatible with the power system frequency standards in most regions of the world. Whether it is a 50Hz power frequency grid or a 60Hz special grid environment, it can maintain stable performance, ensuring the accuracy of protection and measurement functions.

(II) Protection Function Parameters

• Differential Protection: Equipped with high-performance differential protection function. The differential current operating range can be flexibly set, and the minimum operating current is usually as low as 0.2 times the rated current, which can sensitively capture minor faults inside the transformer. It adopts advanced algorithms to effectively avoid misoperation caused by normal transient processes such as inrush current. The action time is fast, generally less than 50ms, which can respond quickly in the early stage of internal faults of the transformer, minimizing equipment damage.

• Overcurrent Protection: Configured with multi-stage overcurrent protection, including instantaneous overcurrent, time-limited instantaneous overcurrent, and overload protection. Instantaneous overcurrent protection can set a higher operating current to deal with severe short-circuit faults with a short action time; time-limited instantaneous overcurrent protection targets a certain range of fault currents and achieves protection selectivity by setting a reasonable delay; overload protection is used to monitor the overload state of the transformer. When the load exceeds the set value, it issues an alarm signal or trips with a delay to prevent the transformer from overheating and being damaged due to long-term overload.

• Other Protection Functions: It also has ground fault protection, overtemperature protection, gas protection interface, etc. Ground fault protection can sensitively detect ground faults in the transformer neutral grounding system, and the operating current and time can be flexibly adjusted; overtemperature protection starts protection when the temperature exceeds the set threshold by receiving signals from the transformer temperature sensor; the gas protection interface can be connected to the signal of the transformer's gas relay to realize monitoring and protection of the internal oil quality and gas state of the transformer.

(III) Communication and Measurement Parameters

• Communication Protocols: Fully supports a variety of mainstream communication protocols, such as IEC 61850, Modbus RTU/TCP, DNP3, etc., facilitating seamless connection with substation automation systems, SCADA systems, etc., realizing real-time data transmission and remote monitoring, and meeting the needs of automation and intelligence in modern power systems.

• Measurement Accuracy: The measurement function covers various parameters such as three-phase voltage, current, active power, reactive power, power factor, frequency, and electrical energy. The measurement accuracy is high, with voltage and current measurement accuracy up to class 0.2, and power measurement accuracy up to class 0.5, providing accurate data support for transformer operating status evaluation and energy efficiency analysis.

(IV) Physical and Environmental Parameters

• Dimensions: Adopting a compact design, it has a small size, usually about 145mm × 145mm × 210mm (length × width × height). It saves installation space, is convenient for installation and layout in switch cabinets, and is especially suitable for power distribution scenarios with limited space.

• Environmental Adaptability: The operating temperature range is -25℃ to +70℃, enabling stable operation in harsh temperature environments; it can work reliably in a relative humidity range of 5%-95% (no condensation) and has good moisture resistance; the protection level reaches IP40, which can effectively prevent the intrusion of dust and water splashes, protect internal circuit components, and extend the service life of the equipment.

III. Functional Characteristics

(I) Comprehensive Protection Functions

• Accurate Fault Identification: Built-in advanced signal processing and fault identification algorithms, it can conduct real-time analysis of current, voltage, temperature, and other signals during transformer operation, and accurately distinguish between internal faults, external faults, normal operating status, and various transient processes. For example, when the transformer is Airdrop，it can effectively identify the inrush current to avoid misoperation of differential protection; when internal faults such as winding short circuits and iron core faults occur, it can quickly and accurately judge and activate protection.

• Flexible Protection Configuration: It supports users to personalize protection parameters through special configuration software according to the actual situation of the transformer's capacity, wiring mode, operating environment, etc. The Drop out，action value, action time, etc. of each protection function can be flexibly adjusted, so that the protection scheme can perfectly match the operating characteristics of the transformer, improving the reliability and selectivity of protection.

(II) Efficient Measurement and Control

• Real-time Data Monitoring: Real-time monitoring of various operating parameters of the transformer, real-time display through a clear interface, and simultaneous storage and recording of data to form a complete operating log. Users can query the historical operating data and load curves of the transformer at any time, providing a basis for transformer status evaluation and maintenance plan formulation.

• Flexible Control Operations: It has local and remote control functions and can control auxiliary equipment such as the transformer's cooling system and tap changer. Through panel operations or upper computer commands, the start and stop of cooling fans and the adjustment of tap changer gears can be realized, ensuring that the transformer operates in the best state and improving operating efficiency.

(III) Intelligent Communication and Diagnosis

• Convenient Data Interaction: With rich communication interfaces and protocols, it realizes seamless communication with the upper control system, uploads real-time data such as transformer operating status and protection action information, and receives control commands from the upper system at the same time, realizing remote monitoring and management, and improving the automation level of the power system.

• Comprehensive Self-diagnosis Function: It has strong self-diagnosis capability and can real-time monitor the operating status of its own hardware and software. When memory faults, communication abnormalities, power faults, and other problems are detected, it can issue alarm signals in time and record fault information, facilitating maintenance personnel to quickly locate and troubleshoot faults, shortening fault handling time, and improving equipment availability.

IV. Application Scenarios

(I) Industrial Enterprises

(II) Commercial and Civil Buildings

(III) Public Utilities