7.9 Automatic Control System
7.9.1 The control mode of a hydropower station should be designed as unattended（or attended with a few guards）.
7.9.2 The control of hydraulic turbine-generator unit and auxiliary equipment shall be designed according to the stipulations for unit automation and shall be able to realize the following functions:
1 The startup or shutdown of the hydraulic turbine-generator unit can be accomplished by a single command.
2 The active power and reactive power of the hydraulic turbine-generator unit can be automatically regulated.
3 The auxiliary equipment of units，cooling water supply and drainage system，and compressed air system can be controlled automatically or manually on site.
7.9.3 The control of hydraulically or electrically operated inlet valves or quick shutoff gates of hydraulic turbines shall be included in the automatic operation of the units and on-site operation thereof shall be enabled.During an emergency of unit，the inlet valves or quick shutoff gates shall be closed automatically.
7.9.4 A computer-based monitoring and control system should be adopted for the automatic control of the hydropower station.
7.9.5 The static thyristor excitation system should be adopted for generators，while brushless excitation system may also be used for small capacity generators.(https://www.daowen.com)
7.9.6 The automatic excitation controller of generator shall meet the following requirements:
1 If a fault occurs to the power system that results in a sudden decrease of output voltage of the generator，forced excitation shall take place.
2 For over-voltage caused by the increase in rotational speed of the hydraulic generator，forced decrease in excitation shall take place.
7.9.7 Automatic de-excitation devices shall be installed for the excitation systems of generators.
7.9.8 If there is a central control room，the equipment to be controlled shall include inlet valves or quick shutoff gates，hydraulic turbine-generator units，transformers，10kV and above lines，circuit breakers on the high voltage side of plant transformers in nearby areas and the dam site，and direct current systems.
7.9.9 The central alarm signal should be operated by the computerized system.
7.9.10 Manual and automatic quasi-synchronization devices with asynchronous blocking shall be installed in the hydropower station.
7.9.11 The circuit breakers at the outlet of generator，at the high voltage side of the generator-transformer unit connection，on the line with power source on the opposite side and at bus sections.shall be capable of synchronous operation.
