ABB REM54 motor terminal troubleshooting

ABB REM54 motor terminal troubleshooting

Introduction: REM54 is not a regular feeder protection, troubleshooting should first look at the overall integrity of the "machine terminal"

ABB REM 543 and REM 545 belong to the REM 54_ series of rotating machine terminals, aimed at small and medium-sized diesel, hydropower, steam turbine generators and generator transformer units. They are also used for starting and operating protection of large and medium voltage synchronous motors and asynchronous motors such as pumps, fans, mills, crushers, etc. Unlike feeder protection, REM54 integrates protection, control, measurement, status monitoring, PLC logic, and communication into one device. Analog inputs can be connected to conventional current/voltage transformers or ABB's Rogowski coils and voltage dividers. The device also has a virtual simulation channel, which calculates neutral current and residual voltage using phase current and phase voltage.

When there is a "motor start trip", "generator differential misoperation", "grounding protection not working", "reclosing/control command failure", or "communication interruption" on site, it is not enough to only check one set value. The troubleshooting of REM54 should follow the sequence of "first check the self-test and power supply, then verify the analog input and sensors, then check the protection function and differential/grounding logic, and finally check the control, communication, and whole machine replacement". Special attention should be paid to the fact that the components of REM54 are calibrated together with the entire machine, and the documentation clearly states that spare parts are not provided separately. In the event of a malfunction, the supplier should be consulted, and it is not possible to replace only one board like a regular plug-in.

First, check the self-test, power supply, and temperature: Ready light flashing and IRF code are first-hand information

REM54 has a relatively complete self checking system that monitors RAM, ROM, parameter storage, CPU watchdog, power supply, digital I/O module, HMI module, RTD/analog input module, internal communication bus, A/D converter, and analog multiplexer. When an internal fault is detected, the green Ready indicator light starts flashing, and the HMI displays a fault text. At the same time, the self-test output relay acts and locks the protection trip output. At this point, you should first read the IRF fault code in the main menu, record the fault type, and then decide whether to power off for inspection. Do not reset repeatedly directly, otherwise the fault information may be lost.

In terms of power supply, REM54 requires reliable auxiliary voltage. PS1/240V supports 110/120/220/240V AC or 110/125/220V DC; PS1/48V supports 24/48/60V DC. The power module has a low auxiliary voltage indication: when the power supply voltage is about 10% lower than the minimum rated DC input of the power module, the internal ACFail signal will activate. This signal can be connected to any signal output in the configuration. If there are "repeated device restarts", "Ready light abnormality", or "protection indefinite lockout" on site, the auxiliary power supply ripple, instantaneous interruption, and battery voltage should be checked. The document provides auxiliary DC interruption time: less than 50ms at 110V and less than 100ms at 200V should not be reset; If the actual interruption exceeds this range, the power circuit and backup power supply should be checked.

REM54 also has internal overheating monitoring, which sends an overheating signal when the temperature inside the casing rises to about+78 ° C (+75...+83 ° C). If the temperature inside the cabinet is high in summer and the device frequently reports overheating, the ventilation inside the cabinet, filter blockage, and installation spacing should be checked instead of adjusting the protection settings.

Analog input and sensor: the part most likely to be "wrongly connected" in REM54 troubleshooting

REM54 has two analog input schemes based on hardware versions: hardware number REM54x_xxxAAAA/CAAA/AAAB is configured as a matching transformer; REM54x_xxxAABA/CAAB/AABB is configured to match transformer and sensor inputs. The sensor input can be connected to Rogowski coils or voltage dividers, and connected through shielded dual BNC connectors. Unused sensor inputs must be short circuited with dedicated connectors, otherwise interference or measurement abnormalities may be introduced.

The conventional transformer scheme should verify the CT/VT ratio, polarity, star point grounding, and secondary load. The sensor scheme should verify the sensor direction, shielding layer grounding, connector fastening, and channel scaling factor. Each analog channel of REM54 can be individually set with a scaling factor, where 1.00 indicates that the rated value of the protected equipment is consistent with the rated value of the measuring equipment; If the CT/VT ratio or sensor ratio is not consistent with the device settings, there will be systematic deviations in overcurrent, differential, impedance, and power protection.