ABB RELION ® 650 series RET650 transformer protection device

ABB RELION ®  650 series RET650 transformer protection device

Device application and core functions

General application scenarios

Suitable for two winding/three winding transformers, autotransformers, generator transformer groups, and parallel reactors, providing fast selective protection, monitoring, and control, supporting a wide frequency range (adapted to system disturbances and unit start stop).

Core features:

Differential protection with built-in transformer ratio matching and vector group compensation, without the need for intermediate CT;

2nd/5th harmonic braking suppresses excitation inrush current and overexcitation;

Supports IEC 61850-9-2LE process bus and can connect to 4 merging units (MU);

Pre configuration package (A01: single circuit breaker two winding transformer; A05: Single circuit breaker three winding transformer.

Main protection functions

Differential protection:

T2WPDIF (two windings)/T3WPDIF (three windings): Based on the theory of symmetrical components, it can detect internal inter turn faults with high sensitivity, support stable fault crossing and surge current braking.

REFPDIF (low impedance limited ground fault): Quickly detect winding ground faults, including directional zero sequence current criteria.

Backup protection:

Current protection: instantaneous phase overcurrent (PHPIOC), four step directional phase overcurrent (OC4PTOC), etc;

Voltage protection: Two step undervoltage (UV2PTUV), overvoltage (OV2PTOV), residual overvoltage (ROV2PTOV);

Frequency protection: Underfrequency (SAPTUF), Overfrequency (SAPTOF), Frequency Change Rate (SAPFRC).

Configuration and Analog Input

device configuration

The basic configuration includes one binary input module and one output module, supporting custom logic (such as automatic opening/closing logic) through PCM600 tool.

A01 configuration: Two winding transformer, including differential protection, overcurrent protection, voltage monitoring, etc., suitable for 12 analog inputs (7I+5U).

A05 configuration: Three winding transformer with extended winding related protection functions, supporting multiple circuit breaker scenarios.

Analog input settings

Current channel: CT transformation ratio (CTprim/CTzc) and star point direction (CTStarPoint: ToObject/FromObject) need to be set, examples include star/triangle CT connection methods and parameter calculations.

Voltage channel: Set the VT ratio (VTprim/VTsec), support star/open delta VT connections, and provide different wiring schemes for high/low impedance grounding systems.

Key parameters: The reference current (IBase) should match the CT rated current, and the minimum operating value should not be less than 4% of the rated value of the IED input (40mA for 1A input and 200mA for 5A input).

Local HMI and Operations

Hardware composition

320 × 240 pixel LCD display screen, 15 programmable tri color LEDs (red/yellow/green), navigation keyboard (including function keys, directional keys, confirm/cancel keys).

LED indication: Ready (running status), Start (protection start), Trip (trip), supports multi page display and priority control.

functional operation

Menu navigation: Access settings, events, measurements, and other functions through the Main menu, supporting parameter modification (numerical/string/enumeration types).

Communication port: Front end RJ-45 port (default IP: 10.1.150.3), only used for temporary debugging, not connected to LAN.

Detailed explanation of core protection functions

Differential protection (T2WPDIF/T3WPDIF)

Principle: Compare the current flowing into/out of the transformer, compensate for the ratio and phase difference, and distinguish internal/external faults through braking characteristics (proportional braking, second harmonic braking).

Key settings:

Minimum operating current (IdMin): default 0.3 times rated current;

Braking characteristics: Three slope sections (Section 1/2/3), suitable for different fault current ranges;

Zero sequence current compensation (ZSCurrSubtrWx): eliminates the influence of zero sequence current caused by external grounding faults.

Low impedance limited ground fault (REFPDIF)

Applied to windings directly grounded or grounded through a zig zag transformer, detecting the difference between neutral wire and phase current, the action value (IdMin) is usually set to 30% of the rated current of the winding.

Overexcitation protection (OEXPVPH)

Based on V/Hz ratio monitoring of iron core overexcitation, it supports custom inverse time characteristics and is suitable for scenarios such as generator step-up transformers. The action time is related to the overexcitation multiple (such as an action time of about 100 seconds at 1.2 times).

Control and Communication

device control

Support the control of circuit breakers (SXCBR) and isolating switches (SCSWI), including a "select execute" mechanism to ensure operational safety.

Automatic voltage control (TR1ATCC/TR8ATCC): regulates voltage through on load tap changers, supports single/parallel transformer control, including line voltage drop compensation and circulating current suppression.

communication protocol

Supports IEC 61850-8-1 (GOOSE for horizontal communication), DNP3.0, IEC 60870-5-103, etc., and is compatible with station level automation systems.