Since PowerFactory 2026, a check was introduced to make sure that the correct number of signals is being sent and received by either block taking part in this exchange. The number output signals sent by the sending block must match the number of input signals received by the receiving block. Otherwise, PowerFactory will report an error.

Replacing the old relays with the new ones from the DIgSILENT Library will fix the issue, otherwise the user must manually correct the signals.

To fix this, the user must locate the block in question, which will be conveniently reported in the output window, identify which blocks have a mismatch in the signal number and correct this in the Type Diagram (white background). Once done, one must re-build the diagram by pressing the re-build button or press the Slot Update button within the Relay Type.