ABB RELION ® 615 series REU615 voltage protection and control relay

ABB RELION ®  615 series REU615 voltage protection and control relay

Product overview

REU615 is ABB RELION ®  There are two standard configurations (A and B) for voltage protection and control relays in the 615 series. Configuration A is applicable to voltage and frequency based protection schemes in power systems and distribution systems, including networks with distributed generation; Configuration B is specifically designed for automatic voltage regulation of power transformers equipped with on load tap changers. Both configurations have additional functions such as circuit breaker control, measurement, and monitoring, and adopt a compact withdrawable unit design, fully utilizing the potential of IEC 61850 standard in communication and interoperability between substation automation equipment.

Core functions and features

Protection function

Voltage protection: including three-phase overvoltage protection (3U>), three-phase undervoltage protection (3U<), residual overvoltage protection (Uo>), positive sequence undervoltage protection (U1<), negative sequence overvoltage protection (U2>), etc., which can cope with different voltage abnormal situations.

Frequency protection: It has over/under frequency (f>/f<) and frequency change rate (df/dt) protection functions to prevent damage to network components caused by abnormal system frequency.

Overcurrent protection: Configuration B includes three-phase non directional overcurrent protection (low, high, instantaneous stages) for detecting overcurrent and short circuit faults.

Thermal overload protection: Configure B's three-phase thermal overload protection (with two time constants) to monitor the thermal stress of the transformer winding and prevent premature aging of the winding insulation.

Other protections include arc protection (optional configuration A), multi-purpose protection, and other functions.

Control function: Supports circuit breaker control, isolation switch control, grounding switch control, on load tap changer control, etc., which can achieve effective control and interlocking of primary equipment.

Measurement function: It can measure various electrical parameters such as three-phase current, voltage, residual current, residual voltage, sequence current, sequence voltage, power, energy, frequency, etc. It can also perform RTD/mA measurement (configuration B is optional).

Data recording and event recording

Disturbance recorder: capable of recording analog and digital channel data, with sampling frequency varying depending on the rated frequency, adjustable recording length, and diverse triggering methods.

Fault record: Record fault related data for easy fault analysis and diagnosis.

Load curve recording: The load history of the corresponding feeder can be observed.

Communication function: Supports multiple communication protocols, including IEC 61850 (supporting Edition 2), IEC 61850-9-2 LE (process bus) IEC 60870-5-103、Modbus ®、 DNP3, etc., have Ethernet redundancy (HSR, PRP), self-healing Ethernet ring and other functions, which can achieve secure communication.

Human Computer Interaction: Equipped with Local HMI (LHMI) and Web HMI (WHMI), LHMI includes a display screen, LED indicator lights, and keyboard for easy local settings, monitoring, and control; WHMI can securely access relays through a web browser.

Authorization and Audit Tracking: Four predefined user categories (VIEWER, OPEROTOR, ENGINEER, and ADMINIST) are defined, each with different permissions; Equipped with audit tracking function to record critical systems and security related events.

Standard configuration

Configuration A

Application scenario: It is applicable to voltage protection and synchronization check in the medium voltage network. It can handle the fault caused by abnormal voltage in the power system, and can handle the synchronization and power on check of two galvanically interconnected networks.

Main functions: including voltage protection (overvoltage, undervoltage, residual voltage, sequence voltage, etc.), frequency protection, load shedding and recovery, arc protection (optional), synchronous inspection, as well as control functions such as circuit breakers, isolation switches, grounding switches, etc.

Configuration B

Application scenario: Used for automatic voltage regulation of power transformers equipped with on load tap changers, including three-phase non directional overcurrent protection, three-phase undervoltage and overvoltage protection, etc.

Main functions: In addition to voltage protection, overcurrent protection, thermal overload protection, etc., it also has functions such as on load tap changer control and voltage regulation, tap changer position indication, etc. The optional RTD/mA input module is used for temperature measurement, etc.

Technical parameters and requirements

1、 Requirements for measuring transformers

（1） Current Transformer (CT)

Requirements for CT for overcurrent protection

Accuracy level and accuracy limit coefficient: The accuracy level of current transformers used for protection is usually represented by "P" (meaning protection), followed by the number indicating the maximum allowable composite error at the rated accuracy limit current. For example, 5P10 represents an accuracy level of 5P and an accuracy limit coefficient of 10. Both 5P and 10P levels are suitable for non directional overcurrent protection, with 5P level having higher accuracy.

Actual accuracy limit coefficient calculation: The actual accuracy limit coefficient (F a) is related to the rated accuracy limit coefficient (F n), CT rated load (S n), CT internal secondary load (S in), and actual external load (S). The calculation formula is:

F a ≈ F n × ∣ S n+S ∣∣ S in+S n ∣ CT selection principle: For non directional overcurrent protection, it is recommended to choose a CT with an actual accuracy limit factor of at least 20. The rated primary current (I 1n) of the CT should meet the requirement of I 1n>I kmax/100 (I kmax is the maximum fault current) to avoid exceeding the thermal and dynamic intensity of the input current measurement of the protective relay.

Suggestion for starting current setting: If I kmin is the lowest current that should be activated during the highest set overcurrent stage, the starting current should be set to:

The current starting value, with a coefficient of 0.7, takes into account protection relay error, CT error, and short-circuit calculation deviation.

2、 Input parameters

（1） Incentive input

Phase current (configuration B)

Terminals: X120:7-8 (IL1), X120:9-10 (IL2), X120:11-12 (IL3)

Can be used for single-phase or two-phase applications, where some excitation inputs can be left vacant, but at least X120:7-8 needs to be connected

Residual current (configuration B)

Terminal: X120:13-14 (Io)

Phase voltage (configuration B)

Terminals: X120:1-2 (U1), X120:3-4 (U2), X120:5-6 (U3)

Phase voltage (configuration A)

Terminals: X130:11-12 (U1), X130:13-14 (U2), X130:15-16 (U3)

SECRSYN1 reference voltage (configuration A)

Terminal: X130:9-10 (U12B)

Residual voltage (configuration A)

Terminal: X130:17-18 (Uo)

（2） RTD/mA input (configuration B optional)

Terminals and corresponding functions:

X130:1-2：mA1（AI1）

X130:3-4：mA2（AI2）

X130:5-6：RTD1（AI3）

X130:7-8：RTD2（AI4）

X130:9-10：RTD3（AI5）

X130:11: RTD channels 1-3 common ground

X130:12: RTD channels 4-6 common ground

X130:13-14：RTD4（AI6）

X130:15-16：RTD5（AI7）

X130:17-18：RTD6（AI8）