Load Shedding Control System for Pumps
A method for controlling a pumping system includes a pump, a pump motor, a generator that provides power to the pump motor and an engine that drives the generator. The method includes the steps of operating the pump at a first operational speed, detecting a transient high load event, reducing the speed of the pump to a second operational speed, detecting the end of the transient high load event, and increasing the speed of the pump to the first operational speed.
1 . A method for controlling a pumping system that includes a pump, a pump motor, a generator that provides power to the pump motor and an engine that drives the generator, the method comprising the steps of:
operating the pump at a first operational speed;
detecting a transient high load event;
reducing the speed of the pump to a second operational speed;
detecting the end of the transient high load event; and
increasing the speed of the pump to the first operational speed.
2 . The method of claim 1 , wherein the step of operating the pump at a first operational speed comprises rotating a progressing cavity pump at the first operational speed.
3 . The method of claim 1 , wherein the step of operating the pump at a first operational speed comprises raising and lowering a reciprocating pump at the first operational speed.
4 . The method of claim 1 , wherein the step of detecting a transient high load event further comprises measuring a change in the intake manifold pressure of the engine.
5 . The method of claim 4 , wherein the step of detecting a transient high load event further comprises detecting a load on the engine that exceeds about 70% of the capacity of the engine.
6 . The method of claim 1 , wherein the step of reducing the speed of the pump to a second operational speed comprises reducing the speed of the pump to a second operational speed that is about 60% of the first operational speed.
7 . The method of claim 1 , wherein the step of detecting the end of the transient high load event further comprises detecting a load on the engine that is less than about 70% of the capacity of the engine.
8 . The method of claim 1 , further comprising a step of operating the pump at the second operational speed during the transient high load event.
9 . A method for controlling a submersible progressing cavity pump, the method comprising the steps of:
connecting the submersible progressing cavity pump to a surface-mounted drive assembly with a rotatable polished rod, wherein the drive assembly includes a pump motor;
connecting the pump motor to a generator;
connecting the generator to an engine configured to drive the generator;
activating the engine, generator and pump motor to rotate the submersible progressing cavity pump at a first operational speed;
detecting a transient high load event;
reducing the rotational speed of the submersible progressing cavity pump to a second operational speed;
detecting the end of the transient high load event; and
increasing the rotational speed of the submersible progressing cavity pump to the first operational speed.
10 . The method of claim 9 , wherein the step of detecting a transient high load event further comprises measuring a change in the intake manifold pressure of the engine.
11 . The method of claim 10 , wherein the step of detecting a transient high load event further comprises detecting a load on the engine that exceeds about 70% of the capacity of the engine.
12 . The method of claim 9 , wherein the step of reducing the rotational speed of the progressing cavity pump to a second operational speed comprises reducing the rotational speed of the progressing cavity pump to a second operational speed that is about 60% of the first operational speed.
13 . The method of claim 9 , wherein the step of detecting the end of the transient high load event further comprises detecting a load on the engine that is less than about 70% of the capacity of the engine.
14 . The method of claim 9 , wherein the step of connecting the pump motor to a generator further comprises the connecting the pump motor to a hydraulic generator that provides a source of pressurized hydraulic fluid to the pump motor.
15 . A method for controlling a reciprocating pump, the method comprising the steps of:
connecting the reciprocating pump to a pump jack motor;
connecting the pump jack motor to a generator;
connecting the generator to an engine configured to drive the generator;
activating the engine, generator and pump jack motor to cause the reciprocating pump to reciprocate at a first operational speed;
detecting a transient high load event;
reducing the operational speed of the reciprocating pump to a second operational speed;
detecting the end of the transient high load event; and
increasing the operational speed of the reciprocating pump to the first operational speed.
16 . The method of claim 15 , wherein the step of detecting a transient high load event further comprises measuring a change in the intake manifold pressure of the engine.
17 . The method of claim 16 , wherein the step of detecting a transient high load event further comprises detecting a load on the engine that exceeds about 70% of the capacity of the engine.
18 . The method of claim 15 , wherein the step of reducing the speed of the pump to a second operational speed comprises reducing the speed of the pump to a second operational speed that is about 60% of the first operational speed.
19 . The method of claim 15 , wherein the step of detecting the end of the transient high load event further comprises detecting a load on the engine that is less than about 70% of the capacity of the engine.
20 . The method of claim 15 , further comprising a step of operating the pump at the second operational speed during the transient high load event.