Based on the electrical differences between gas turbine generation and coal-fired power generation, this paper analyzed the protection effectiveness traditionally used in coal-fired unit for gas turbine generator in variable frequency starting process. Some special protection configurations were studied, such as overcurrent protection, stator ground fault protection, main transformer differential protection, generator low-frequency protection and stator low voltage protection, during the variable frequency starting progress of gas turbine generator. A typical protection configuration was proposed for gas turbine generator units (≥300 MW), according to the comparison of protection configuration between gas turbine generation and coal-fired generation under the mode of grid-connected operation.