What is the difference between phase and line voltage?

Line voltage (line-to-line voltage) in a polyphase system is the voltage between two given phases.

On the other hand, Phase voltage is the voltage between the given phase and neutral. Note that neutral is available in star connection but not delta connection.

Line voltage (line-to-line voltage) in a polyphase system is the voltage between two given phases.

On the other hand, Phase voltage is the voltage between the given phase and neutral. Note that neutral is available in star connection but not delta connection.

Phase Voltage: It is the phasor potential of a phase wire with respect to neutral wire.
Line Voltage: It is phasor potential of a phase wire with respect to another phase wire.