What is “Under excited” in electrical system?

“Under excited” refers to a condition in an electrical system where the magnetic field produced by the excitation current is less than the normal or rated level.
For example, in a generator, under excitation means that the output voltage might be lower than expected. It can also occur in transformers, where it can affect the voltage transformation ratio and power transfer efficiency.
In practical applications, under excitation can lead to issues such as reduced power quality, increased losses in the system, and potential instability in the electrical network.