Steam turbine generator unit system capable of efficiently operating in wide load interval

The utility model discloses a steam turbine generator unit system capable of efficiently operating in a wide load interval, and solves the problems of high power generation heat consumption rate and poor safety when a traditional steam turbine generator unit operates in a low load. When the overall power generation load of the steam turbine generator unit is smaller than or equal to the rated power generation load of the main unit, a steam admission regulating valve on an auxiliary steam guide pipe of a medium-low pressure cylinder is closed, a circuit breaker is disconnected, the low pressure cylinder of the auxiliary unit stops steam admission and power generation, and the auxiliary unit is converted into a standby or shutdown state; due to quitting of the auxiliary unit, all exhaust steam of the turbine intermediate-pressure cylinder flows through the turbine main low-pressure cylinder to be exhausted, so that the volume flow of the exhaust end of the turbine main low-pressure cylinder can be recovered to