SMV stream’s quality bits in sending direction - Arc protection - Bay control and measurement - Merging unit - Transformer protection - 2 winding - Feeder protection - Voltage regulation - Capacitor bank protection - Grid automation - Busbar differential protection (high impedance) - Line differential protection - Back-up protection - Motor protection - Busbar protection (voltage and frequency) - Interconnection protection - Generator protection - Power management/Load shedding - IEC 61850 Engineering Guide - REX615 Protection and control - PCL2 - IEC - ANSI - 20.04.2026

REX615 IEC 61850 Engineering Guide

Table 1. Explanation of quality bits in sending direction
Quality bit Description
smpSynch

Synchronization accuracy for all channels in the SMV frame.

0: less than 4 µs synchronization accuracy

1: within 4 µs synchronization accuracy

test bit The sender IED is in test mode.
invalid 01 & bad reference The sender time synchronization is uninitialized (accuracy unknown).
The sender has time accuracy less than 100 ms.
invalid 01 The channel is not available.
questionable 11 & inaccurate The accuracy of the measurement value is inaccurate or not supported.
derived The channel is derived from other channels, for example, calculated residual voltage.