ABB REF620 (Relion 620 series) feeder protection and measurement device

ABB REF620 (Relion 620 series) feeder protection and measurement device

Product positioning: Why REF620 is suitable for feeder protection and renovation projects

ABB REF620 is a feeder protection and control IED in the Relion 620 series, designed for the protection, control, measurement, and monitoring of utility and industrial distribution systems. It is suitable for radial, ring network, and mesh distribution networks, and can be configured with various switchgear configurations such as single bus or double bus, single circuit breaker or double circuit breaker. For existing renovation projects, the value of REF620 lies not only in its "multiple protection functions", but also in its extractable unit design, expandable functionality, support for IEC 61850, and two default configurations of traditional CT/VT and sensor input, making it easy to choose between different cabinet types and measurement schemes.

REF620 provides two default configurations: Configuration A uses traditional current and voltage transformer inputs; Configuration B uses current and voltage sensor inputs. The default configuration can be used as the starting point of the project, but it cannot be directly applied as the end user. On site application configuration, signal matrix configuration, and parameter tuning still need to be done through PCM600. For replacing or adding feeder protection devices, the first step is to verify whether the existing cabinet is a CT/VT or sensor solution, and then determine the hardware variants, I/O quantities, and communication modules of REF620 to avoid discovering a mismatch in wiring methods only after arrival.

Protection function and setting points: from overcurrent to ground fault

The protection functions of REF620 cover a wide range, including three-stage non directional overcurrent, directional overcurrent, non directional grounding fault, directional grounding fault, negative sequence overcurrent, phase failure protection, residual voltage protection, three-phase undervoltage/overvoltage, positive sequence undervoltage, negative sequence overvoltage, frequency protection, thermal overload, circuit breaker failure, surge detection, main tripping, etc. commonly used on site. For networks where the neutral point is not grounded, grounded through resistance, or grounded through impedance, admittance type, harmonic type, wattmeter type grounding fault protection, as well as transient/intermittent grounding fault protection, can also be selected.

Don't just look at the parameters of a single machine during calibration. Overcurrent protection should be combined with the rated current of the feeder, CT ratio, cable current carrying capacity, and the coordination of upper and lower level protection; Grounding fault protection should be combined with neutral point grounding method, zero sequence CT transformation ratio, and on-site capacitive current. Directional overcurrent and directional grounding faults require confirmation of the polarity, wiring group, and directional mode of the voltage transformer. For overhead lines that require reclosing, the coordination between automatic reclosing and overcurrent/ground fault protection should be checked to avoid reclosing with permanent faults. REF620 supports multi instance protection function. When configuring the project, the purpose of each instance should be clearly defined in PCM600 to avoid duplicate or missing configurations.

Control, Interlocking, and HMI: On site operations cannot rely solely on indicator lights

REF620 supports circuit breaker control, isolation switch control, and grounding switch control, and provides corresponding position indications. Each controllable device typically requires two binary inputs and two binary outputs, depending on the selected hardware configuration. If there is insufficient I/O, remote I/O expansion can be achieved through RIO600, but non fast signals should be allocated to external I/O while retaining fast tripping and critical interlock signals of the main body.

The local HMI includes an LCD, 11 programmable LEDs, and 16 configurable manual buttons, supporting local/remote switching. During on-site debugging, it should be confirmed that the indication of the opening and closing position of the circuit breaker is consistent with the actual state; The position signals of the isolation switch and grounding switch are correct; Interlocking logic is implemented through signal matrix or application configuration; The LED and button functions are consistent with the single line diagram. For renovation projects, it is not enough to only check the protection settings, but also the control circuit, auxiliary contacts, trip circuit, and signal circuit. Otherwise, there may be problems such as "protection action but circuit breaker not tripped" or "background display inconsistent with actual position".

Measurement, power quality and recording functions: data foundation for troubleshooting

REF620 can measure three-phase current, zero sequence current, three-phase voltage, zero sequence voltage, and calculate sequence components, frequency, active/reactive power, power factor, electrical energy, and current/power demand. In terms of power quality, it supports monitoring of total current demand distortion, total voltage harmonic distortion, voltage variation, and voltage imbalance. For fault analysis, the device provides disturbance records, fault records, event records, and load curves. Disturbance records can be configured with up to 12 analog channels and 64 binary channels; Event records can store 1024 time stamped events; The fault record can save 128 latest fault events.