ABB REL670 distance protection and troubleshooting

Troubleshooting for large deviations in fault location. LMBRFLO calculates fault distance based on impedance measurement, which requires parameters such as positive/zero sequence impedance of the line, line length, impedance of both sides of the power supply, and zero sequence mutual inductance. If the distance measurement deviation is large, it is necessary to check whether the line parameters are consistent with the actual measurement, whether the CT/VT ratio is correct, and whether the fault type and fault phase are identified correctly. For double circuit lines, setting the zero sequence mutual inductance Z0M incorrectly will significantly affect the distance measurement results. The fault location results should be compared with the voltage and current waveforms in the waveform recording and the inspection results of the fault point, rather than just looking at the single distance measurement values.

Communication, event recording, and hardware replacement

REL670 supports communication such as IEC 61850-8-1, GOOSE, DNP3, IEC 60870-5-103, LON, SPA, etc. The troubleshooting related to distance protection and communication includes: GOOSE disconnection causing the signal to not be received, inconsistent event times at the station control layer, failed upload of disturbed files, and abnormal switching of redundant channels.

GOOSE has broken its chain. First check the fiber optic cables, switch ports, OEM module indicator lights, and then check the GOOSE dataset APPID、 Subscription relationship and network configuration. If GOOSE is disconnected but the protection can still operate, it indicates that the distance protection itself is normal, and the problem lies in the communication configuration or switch.

Events and recording. The disturbance report of REL670 includes event list, indication, event record, trip value record, disturbance record, and fault location. When troubleshooting, the event record should be read first to confirm the timing of protection activation, direction judgment, trip exit, and reclosing commands; Let's take a closer look at the analog and switch values in the disturbance recording. If the event time is inconsistent with the station control layer, the time synchronization source and SynchAccLevel settings should be checked.

Hardware replacement. After replacing modules such as TRM, ADM, NUM, PSM, BIM, BOM, IOM, SLM, OEM, LDCM, etc., it is necessary to verify whether the configuration and parameters have been re downloaded, check SMAI channel mapping, CT/VT ratio, binary input-output mapping, and communication configuration. After replacing the motherboard or NUM, the firmware version, configuration file, and cycle time should be rechecked. For distance protection, a second injection test must be conducted after replacing the TRM or ADM to verify the direction and action boundary of each distance component.

On site troubleshooting checklist: from "phenomenon" to "root cause"

Phenomenon 1: The positive direction fault does not jump. Check CTStarPoint, VT voltage, ZDRDIR direction, STCND/DIRCND connection, distance range switching, minimum operating current RFPE/RFPP。

Phenomenon 2: Wrong tripping due to reverse direction fault. Check CT polarity CTStarPoint、 Direction setting, parallel line zero sequence mutual inductance compensation, power swing locking.

Phenomenon 3: Out of zone faults exceeding the level. Check time difference, load intrusion RFPE/RFPP、 Communication enabled/locked logic, whether ZMRPSB is erroneously locked.

Phenomenon 4: Single phase fault and three-phase tripping. Check FDPSPDIS phase selection, SMPPTRC program, single-phase reclosing mode, and three-phase trip input.

Phenomenon 5: Failed reclosing. Check CBREADY, CBPOS, INHIBIT, SYNC, tSync, reclosing frequency and method.

Phenomenon 6: There is a large deviation in fault distance measurement. Check the line parameters, CT/VT ratio, zero sequence mutual inductance, fault type identification, and impedance of both sides of the power supply.

Phenomenon 7: Communication abnormalities. Check the number and time synchronization of fiber optic/electrical ports, OEM/SLM modules, GOOSE dataset, IEC 61850 clients.