Method for determining regulation range of pumping power of three-machine pumped storage unit

1 . A method for regulating pumping power of a three-machine pumped storage unit, the three-machine pumped storage unit comprising a generator, a water pump, and a hydraulic turbine, a main shaft of the generator having one end connected to the water pump and other end connected to the hydraulic turbine, the method comprising:

determining an allowable regulation range of the pumping power of the three-machine pumped storage unit, wherein,

obtaining a first parameter set of pumping measurement parameters for characterizing the three-machine pumped storage unit, wherein the first parameter set comprises a gravitational acceleration, a water head, an inflow, power absorbed by a power grid, and a design efficiency of a pumped storage power station;

determining a pumping process efficiency based on the gravitational acceleration, the water head, the inflow, and the power absorbed by the power grid, wherein the pumping process efficiency is obtained when the generator, the water pump, and the hydraulic turbine in the three-machine pumped storage unit operate simultaneously;

determining a first relational expression based on the pumping process efficiency and the design efficiency of the pumped storage power station, wherein the first relational expression reflects a relationship between the pumping process efficiency and the design efficiency of the pumped storage power station;

establishing a second relational expression based on the first relational expression, wherein the second relational expression characterizes power of the hydraulic turbine;

determining a third relational expression based on the power absorbed by the power grid and the second relational expression, wherein the third relational expression reflects a first regulation range of the power absorbed by the power grid during pumping by the three-machine pumped storage unit; and

determining a fourth relational expression based on the third relational expression, wherein the fourth relational expression reflects the allowable regulation range of the pumping power of the three-machine pumped storage unit;

wherein, the first relational expression is

g H ( P p η p /gH−P t ( gHη t ))/ P p −P t )≥η power station ;

where g H (P p η p /gH−P t (gHη t ))/P p −P t ) represents the pumping process efficiency, η power station represents the design efficiency of the pumped storage power station, g represents the gravitational acceleration; H represents the water head; P p represents of a power of the water pump, η p represents weighted average efficiency of the water pump, η t represents weighted average efficiency of the hydraulic turbine;

the second relationship is P t ≤(P p η p −AP p )/(1/η t −η power station );

the third relational expression is

P m ≥P p −( P p η p −η power station P p )/(1/η t −η power station );

P m represents the first regulation range of the power absorbed by the power grid during pumping by the three-machine pumped storage unit;

the fourth relational expression is

P p −( P p η p −η power station P p )/(1/η t −η power station )≤ P m ≤P p ;

during pumping operation, operating the water pump and the hydraulic turbine simultaneously,

opening ball valves at an upstream part of the water pump,

opening ball valves of the hydraulic turbine are opened to a certain degree according to a power requirement, and

regulating the pumping power of the three-machine pumped storage unit within the allowable regulation range.

2 . The method according to claim 1 , wherein obtaining power absorbed by a power grid in the first parameter set comprises:

obtaining power of the water pump and the power of the hydraulic turbine; and

calculating the power absorbed by the power grid based on the power of the water pump and the power of the hydraulic turbine.

3 . The method according to claim 2 , wherein obtaining an inflow in the first parameter set comprises:

obtaining a weighted average efficiency of the water pump and a weighted average efficiency of the hydraulic turbine;

calculating a flow of the water pump based on the power of the water pump, the weighted average efficiency of the water pump, the gravitational acceleration, and the water head;

calculating a flow of the hydraulic turbine based on the power of the hydraulic turbine, the weighted average efficiency of the hydraulic turbine, the gravitational acceleration, and the water head, and calculating the inflow based on the flow of the water pump and the flow of the hydraulic turbine.

4 . The method according to claim 3 , wherein determining a first relational expression based on the pumping process efficiency and the design efficiency of the pumped storage power station comprises:

determining the first relational expression based on the gravitational acceleration, the water head, the power of the water pump, the weighted average efficiency of the water pump, the power of the hydraulic turbine, the weighted average efficiency of the hydraulic turbine, and the design efficiency of the pumped storage power station.

5 . The method according to claim 4 , wherein establishing a second relational expression based on the first relational expression comprises:

transforming the first relational expression to obtain the second relational expression, wherein the second relational expression is determined based on the power of the water pump, the weighted average efficiency of the water pump, the weighted average efficiency of the hydraulic turbine, and the design efficiency of the pumped storage power station.

6 . The method according to claim 5 , wherein determining a third relational expression based on the power absorbed by the power grid and the second relational expression comprises:

determining the third relational expression based on the power of the water pump, the weighted average efficiency of the water pump, the weighted average efficiency of the hydraulic turbine, and the design efficiency of the pumped storage power station.

7 . The method according to claim 6 , wherein determining a fourth relational expression based on the third relational expression comprises:

determining a fifth relational expression based on the power absorbed by the power grid, wherein the fifth relational expression reflects a second regulation range of the power absorbed by the power grid; and

determining the fourth relational expression based on the fifth relational expression and the third relational expression.

8 . An apparatus for regulating pumping power of a three-machine pumped storage unit, the three-machine pumped storage unit comprising a generator, a water pump, and a hydraulic turbine, a main shaft of the generator having one end connected to the water pump and the other end connected to the hydraulic turbine, the apparatus comprising:

a processor and a memory storing instructions that, when executed by the processor, cause the processor to perform the following steps;

determining an allowable regulation range of the pumping power of the three-machine pumped storage unit, wherein,

obtaining a first parameter set of pumping measurement parameters for characterizing the three-machine pumped storage unit, wherein the first parameter set comprises a gravitational acceleration, a water head, an inflow, power absorbed by a power grid, and a design efficiency of a pumped storage power station,

determining a pumping process efficiency based on the gravitational acceleration, the water head, the inflow, and the power absorbed by the power grid, wherein the pumping process efficiency is obtained when the generator, the water pump, and the hydraulic turbine in the three-machine pumped storage unit operate simultaneously,

determining a first relational expression based on the pumping process efficiency and the design efficiency of the pumped storage power station, wherein the first relational expression reflects a relationship between the pumping process efficiency and the design efficiency of the pumped storage power station;

establishing a second relational expression based on the first relational expression, wherein the second relational expression characterizes power of the hydraulic turbine;

determining a third relational expression based on the power absorbed by the power grid and the second relational expression, wherein the third relational expression reflects a first regulation range of the power absorbed by the power grid during pumping by the three-machine pumped storage unit; and

determining a fourth relational expression based on the third relational expression, wherein the fourth relational expression reflects the allowable regulation range of the pumping power of the three-machine pumped storage unit;

wherein, the first relational expression is

g H ( P p η p /gH−P t ( gHη t ))/ P p −P t )≥η power station ;

where g H (P p η p /gH−P t (gHη t ))/P p −P t ) represents the pumping process efficiency, η power station represents the design efficiency of the pumped storage power station, g represents the gravitational acceleration; H represents the water head; P p represents of a power of the water pump, η p represents weighted average efficiency of the water pump, η t represents weighted average efficiency of the hydraulic turbine;

the second relationship is P t ≤(P p η p −AP p )/(1/η t −η power station );

the third relational expression is

P m ≥P p −( P p η p −η power station P p )/(1/η t −η power station );

P m represents the first regulation range of the power absorbed by the power grid during pumping by the three-machine pumped storage unit;

the fourth relational expression is

P p −( P p η p −η power station P p )/(1/η t −η power station )≤ P m ≤P p ;

during pumping operation, operating the water pump and the hydraulic turbine simultaneously,

opening ball valves at an upstream part of the water pump,

opening ball valves of the hydraulic turbine are opened to a certain degree according to a power requirement, and

regulating the pumping power of the three-machine pumped storage unit within the allowable regulation range.