Specific features of the control systems of new-modification 310–330-MW steam turbines manufactured by PAO turboatom

Abstract

Principal engineering solutions taken by PAO Turboatom when developing the control systems of the 310–325-MW turbines for thermal power stations are set forth. A schematic diagram of the control system is presented and the designs of the retrofitted basic mechanisms, viz., high-pressure steam-distribution unit and the cutoff valve, are described. It is noted that the accepted principles of designing the control systems allow retaining the following advantages of the latter: use of the condensate as a cheap nonflammable working fluid, valveless switches to control the locking servomotors, a mechanical ring-type turbine trip mechanism (TTM) in combination with an actuator fitted with two double-seated actuator valves to control the pressure in the pulse security lines, and a rotary valve to block the triggering of the actuator valves during successive testing of the TTM rings by filling the oil during the operation of the turbine and the subsequent raising of the above valves. The control systems of the new-modification turbines are based on microprocessor hardware using electromechanical converters to drive every cutoff valve as a universal solution that is not oriented towards a particular manufacturer of the control system electronics. Application of a mechanical turbine trip mechanism is acknowledged as indispensable for unconditional guarantee of the safe operation of the turbines irrespective of the presence of the electronic turbine trip mechanism.