The WARNING output of SMV receive should be connected in the SMV applications to perform the necessary actions in case the SMV angle information is out of the accuracy range. Depending on the protection function operation principle, inaccurate angle information is also seen in the related protection function operation inaccuracy.
Additionally, the ALARM output of SMV receive function should be connected to ensure fail-safe operation in all circumstances. The WARNING output is always internally active whenever the ALARM output is active.
WARNING and ALARM information is internally propagated for the measurement functions. Thus, measurement functions are able to update the measured value quality information accordingly without any additional connections.
The receiver activates the SMV receive WARNING and ALARM outputs if any of the quality bits, except for the derived bit, is activated. When the receiver is in the test mode, it accepts SMV frames with test bit without activating the SMV receive WARNING and ALARM outputs.
The SMV receive WARNING in the receiver is activated if the synchronization accuracy of the sender or the receiver is worse than 4 μs. The output is held on for 10 seconds after the synchronization accuracy returns within limits.
The SMV receive ALARM in the receiver is activated if the synchronization accuracy of the sender or the receiver is unknown, worse than 100 ms or two or more consecutive frames are lost. The output is held on for 10 seconds after the synchronization accuracy returns within limits.
The T_SYNC_OK output of the SMV receive function is set when both the sender and receiver have synchronized their clocks to within the accuracy requirements with an IEEE 1588 grandmaster clock.
The GLOB_SYNC_OK output of the SMV receive function is set when both the sender and receiver have synchronized their clocks with a global IEEE 1588 grandmaster clock, such as a GPS clock.
Quality of received SMV is available as outputs in SMV measurement function block and not propagated directly to protection function blocks along with the SMV measurement values. To handle situations where SMV is not available, its quality is not good or there is an issue with time synchronization, the WARNING, ALARM, T_SYNC_OK and GLOB_SYNC_OK outputs of SMV measurement function blocks must be connected to application, for example to block directional protection.
The amount of received SV streams is practically limited to the number of SVRECEIVE functions and the number of TxTR functions. In addition to these, the following restrictions apply:
- Maximum number of received sampled value streams is 30
- Maximum number of measurement channels in one received sampled value stream is 32
- Maximum number of received sampled value channels is 720 (30 streams with 24 channels each)
Note that all of these are not usable in the application simultaneously because of the limited number of SVRECEIVE functions
- Receiving streams according to IEC 61850-9-2LE and IEC 61869-9 at the same time is not supported.