METHOD TO PROTECT GAS-TURBINE PLANT FROM OVERSPEEDING OF POWER TURBINE Russian patent published in 2008 - IPC F02C9/46 

FIELD: mechanical engineering; gas-turbine plants.

SUBSTANCE: invention relates to control systems of gas-turbine plants, namely, to protection systems of gas-turbine plants used for mechanical drive and drive of electric generator to protect them against dangerous overspeeding of free power turbine. According to proposed method of protection of gas-turbine plant from overspeeding of power turbine at abrupt drop of load including measurement of speed of power turbine, determining its first time derivative and gas generator speed reduced to air temperature at plant input, forming of limiting values and comparing them with , , , respectively, at and bypassing of gas into atmosphere after gas generator turbine is provided. At fulfilling of condition and , bypassing of gas after gas generator turbine into atmosphere is provided bypassing power turbine by means of gas bypass valves. Thanks to it reduction of energy supply to power turbine and counteraction of overspeeding is provided. Moreover, value is found from formula where is setting value of power turbine speed and where is static error of power turbine speed control of gas-turbine plant. Value is obtained experimentally at changing over of gas-turbine plant loads comparable with power in supply networks at operation in parallel with "infinite" power network. Setting value of speed of gas-turbine plant is required to maintain said power. Constant providing required reserve for preventing false operation should be 5-7 times greater than static error of speed of power turbine of gas-turbine plant being approximately 60-100 rpm.

EFFECT: improved reliability, increased service life and safety of gas-turbine plant.

1 dwg