The hydraulic generator for micro hydropower is mostly used synchronous type with capacity if used for standalone usage; they have five frames, 26 siges, Rated frequencies are 50 Hz. The voltage rating is 400v for 3 phase, 230v for single phase (60Hz also can be supplied). According to the arrangement of main shafts, these units have vertical setting and horizontal setting. The double-supported construction is compact-designed. For 50kW below capacity, we prefer to recommend the Rare Earth Permanent Magnet Synchronous Generator for simple structure and stable performance.
For on grid usage, the asynchronous generator is good option because it could be direct grid connection without synchronizing process.
Excitation systems: Brush less excitation with AC exciter; excitation of double winding shunt reactors with SCR and excitation of double winding shunt reactors. Generators are manufactured according to China National standards and in conformity with IEC standards.
The big difference of hydraulic generator from other diesel generator is the tolerance of water turbine runway speed. When the water turbine generator suddenly shakes off the load in operation due to the unit failure, the generator output power is zero, at this time, if the turbine speed control mechanism fails or other reasons make the water guide mechanism cannot be closed, the turbine speed rises rapidly. When the input water flow energy is balanced with the mechanical friction loss energy generated when the rotational speed increases, the rotational speed reaches a certain stable maximum value, which is called the runaway speed of the hydraulic turbine. When the water turbine runaway speed happens, it would easily burnt out the generator. While in our micro hydro system, we equipped dummy load to balance the load changes even 100% drop. Our voltage and frequency regulator would keep the stable always whatever the load changes, take an example if the load drop 10% our dummy load would balance the related percentage load accordingly which would avoid the runaway speed burnt out the generator.