Main distributing valve of dual-working-condition speed regulator of large-scale water-pumping energy storage unit

The invention relates to a main distributing valve of a dual-working-condition speed regulator of a large-scale water-pumping energy storage unit. An upper end cover piston sleeve (3) is mounted in a central hole of an upper end cover (2); a main lining (6) is mounted in a central hole of a valve body (8); a lower end cover piston sleeve (12) is mounted in a central hole of a lower end cover (13); an upper end cover guide piston (4) is mounted in a central hole of the upper end cover piston sleeve (3); and a main piston (7) is mounted in a central hole of the main lining (6). The main distributing valve adopts the two-stage control theory, and is used for realizing different closing velocities in a first stage when the water-pumping energy storage unit is emergently shut down under different working conditions. The main distributing valve is simple in structure and is high in integration degree, so that design cost is greatly reduced; and the main distributing valve can achieve an effect that a single valve c