Analysis of the Permissibility of Load Shedding Modes of Power Unit No. 9 of the Mosénergo CHPP-22

Following the creation of power systems that combined a large quantity of generating equipment, the requirements for maneuverability of steam-powered power units in many respects became less “rigid,” since discharges and load surges are received not by a single unit, but by all power plants operating in the power system, as well as due to the fact that the main tasks of frequency and power regulation were assigned to highly maneuverable hydro generators. Nevertheless, incidents related to the termination of power supply to both individual districts and entire power systems continue to occur. In order to prevent them, frequency and power control systems are being created in the power system, as well as system automation complexes, including frequency load shedding (FLS) units, which carry out auxiliary selection automation (ASA) for power plants or for a balanced area. The allocation of blocks to power own needs is carried out by resetting the load to 10 MW by covering the regulatory channel (RC) of the steam turbine at the command of the electronic turbine control system (ETCS) and acting on the disconnector on the outside of the main electrical circuit of the power unit in combination with the corresponding switching of the steam turbine generator to the transformer of their own needs. According to the technical conditions for delivery [2], the T-295/330-240 turbine provides stable operation at its own needs, amounting to 10% of the nominal. The one-time duration of the turbine operation when the load is discharged to its own needs is no more than 40 min, the total is no more than 200 h per year. The main quantitative limitations of such modes are obtained based on the calculated analysis of the cyclic strength of critical parts of a steam turbine.