Isolated power grid stability control system

The invention discloses an isolated power grid stability control system based on a power grid with a small capacity which breaks away from a large power grid. The isolated power grid stability control system is an important quality indicator and reflects a balance state between supply and demand of active power of a power system. Stable frequency is an important aspect of the power system stability. Normal frequency deviation of the power system is allowed to +/- o.2 Hz. Therefore, at the instant that generating capacity is insufficient and an isolated power grid appears, part load is removed timely according to a decreased amplitude value of the isolated power grid frequency. A turbo generator control system and a load monitoring grading system are designed entirely to enable turbo generator units to keep coordinate control, and safe and stable operation of a power supply and distribution system of a power grid is guaranteed. According to the actual use of load, a turbo generator governing valve works through a digital electro-hydraulic control system (DEH) interface, balance between power generation and power consumption is achieved, quickness of primary and secondary frequency modulation of a generator is ensured, and stability of the system frequency is guaranteed.