Steam turbine is composed of steam turbine body, speed control system, critical guard and oil system, its effect is --
(1) Steam turbine body: generally adopt island type (double layer placement), whole block type (single layer placement), by the boiler output of high temperature and high pressure steam blowing impeller rotation, the heat energy into mechanical energy.
(2) Speed regulation system: when the turbine unit is in grid-connected operation, the opening of the valve is adjusted according to the speed error, the steam inlet and enthalpy drop of the turbine are adjusted, and the active power of the generator is changed, so that the steam inlet automatically increases and decreases when the load changes, and the steam turbine runs stably at the rated speed (3000r/min).
(3) Critical protector: the critical protector is usually installed on the shaft segment of the turbine rotor located in the front bearing seat. When the turbine speed regulation system fails and the speed exceeds 3300r/min, the critical protector acts to close the main valve to avoid turbine damage.
(4) Oil system: the oil system is divided into lubricating oil system and regulating (maintenance) oil system two parts, is the supply of steam turbine and generator everywhere bearing lubricating oil and speed control system oil, its effect is as follows:
A. Each bearing of the unit is supplied with oil to lubricate and cool the bearing.
B. Supply sufficient pressure oil for the regulation system and maintenance device to ensure their normal operation.
C. Supply lubrication oil for each transmission mechanism.
