Electrically isolated pump-off controller

• US 6,315,523 B1
• Filed: 02/18/2000
• Issued: 11/13/2001
• Est. Priority Date: 02/18/2000
• Status: Expired due to Term

• Current Assignee: D-Jax Corporation
• Original Assignee: D-Jax Corporation
• Inventors: Mills, Manuel D.
• Primary Examiner(s): TYLER, CHERYL JACKSON
• Application Number:
  US09/507,772
• Time in Patent Office: 634 Days
• Field of Search: 417/45, 417/44.1, 417/53, 318/430, 307/31, 307/32, 307/150
• US Class Current: 417/45
• CPC Class Codes: F04B 47/02 the driving mechanisms being situated at ground level F04B47/12 takes precedence
• CPC Class Codes: F04B 49/065 and making use of computers

Abstract

Electrical isolation method and assembly that protects a pump-off controller 31 as used for controlling the pumping of a subterranean well, from lightning and transient electrical power surges by electrically isolating the pump-off controller 31, the isolation assembly including fiber optic cables 17, 18, signal converters to convert electrical signals to optical signals 25, 33, signal converters to convert optical signals to electrical signals 32, 19 and a solar panel 35 to power the pump-off controller 31. Components of the fiber optic and control assembly may also be electrically protected from lightning and electrical power transients by including an isolation transformer 53, components to drive the isolation transformer 53, metal oxide varisters, fuses and other protection devices. Signals from the pump-off controller 31 may be used to stop/start a prime mover 45 for a pumping unit 46, or regulate the speed of the prime mover 45.

Claims

1. A pump-off control assembly for controlling a prime mover powering a pumping

unit of a pumping system for lifting fluids from a well, comprising:

a power source to power the prime mover;

a controller to control the power to the prime mover;

at least one sensor mounted on the pumping system for sensing operating characteristics of the pumping system and for transmitting an electrical first signal from the at least one sensor to a first signal converter;

the first signal converter converting the electrical first signal to an optical second signal;

a first fiber optic cable transmitting the optical second signal to a second signal converter;

the second signal converter converting the optical second signal into an electrical third signal;

a pump-off controller processing the electrical third signal and for outputting an electrical fourth signal to a third signal converter;

the third signal converter converting the electrical fourth signal to an optical fifth signal;

one of the first fiber optic cable and a second fiber optic cable transmitting the optical fifth signal to a fourth signal converter;

the fourth signal converter converting the optical fifth signal to an electrical sixth signal and transmitting the electrical sixth signal to an amplifier; and

the amplifier amplifying the electrical sixth signal and generating an electrical seventh signal to regulate the controller.

2. The pump-off control assembly as defined in claim 1, further comprising:

the power source is a high voltage AC power source;

the controller includes a motor contactor to normally transmit the high voltage AC power to the prime mover, the contactor selectively operable to interrupt the high voltage AC power to the prime mover; and

a motor relay receiving the electrical seventh signal and transmitting an electrical eighth signal to the motor contactor to selectively operate the motor contactor.

3. The pump-off control assembly as defined in claim 2, further comprising:

at least one transformer for transforming a portion of the high voltage AC power to a low voltage AC power, the low voltage AC power powering at least the amplifier.

4. The pump-off control assembly as defined in claim 3, further comprising:

a first bridge rectifier rectifying a portion of the low voltage AC power to provide a first substantially DC current to drive an oscillator;

the oscillator powered by the first substantially DC current, the oscillator to provide a substantially AC current to drive an electrical isolation transformer;

the electrical isolation transformer to electrically isolate the oscillator from the at least one sensor; and

a second bridge rectifier receiving power from the electrical isolation transformer to provide a second substantially DC current to the at least one sensor.

5. The pump-off control assembly as defined in claim 4, further comprising;

at least one first voltage regulator to maintain substantially constant voltage in the oscillator; and

at least one second voltage regulator to maintain substantially constant voltage in the electrical isolation transformer.

6. The pump-off control assembly as defined in claim 3, further comprising;

a motor control panel for housing the at least one transformer, the motor contactor, the first signal converter, the fourth signal converter and the motor relay.

7. The pump-off control assembly as defined in claim 3, wherein the at least one transformer comprises:

a high voltage AC transformer to transform a high voltage to a medium voltage to provide an intermediate voltage source; and

a medium voltage AC transformer to transform a medium voltage to a low voltage to provide the low voltage AC power.

8. The pump-off control assembly as defined in claim 3, further comprising:

at least one circuit overload protector electrically between the high voltage AC power source and a high voltage side of the at least one transformer to provide lightning and transient voltage and current protection to the at least one transformer.

9. The pump-off control assembly as defined in claim 3, further comprising:

at least one circuit overload protector electrically between the lower voltage side of the at least one transformer and the first bridge rectifier to provide lightning and transient voltage and current protection to the at least one transformer and the first bridge rectifier.

10. The pump-off control assembly as defined in claim 1, further comprising:

a motor control panel for housing the first signal converter and the fourth signal converter; and

a pump-off control panel for housing the pump-off controller, the pump-off control panel being electrically isolated from the motor control panel.

11. The pump-off control assembly as defined in claim 1, further comprising:

at least one circuit overload protector electrically between the at least one sensor and the first signal converter to provide lightning and transient voltage and current protection to the first signal converter and the at least one sensor.

12. The pump-off control assembly as defined in claim 1, further comprising:

a solar panel to power the pump-off controller.

13. The pump-off control assembly as defined in claim 12, further including:

a battery to provide backup power to the pump-off controller, the battery being recharged by the solar panel.

14. A method of controlling a prime mover which powers a pumping unit of a pumping system for pumping fluid from a well, the method comprising:

providing a power source to power the prime mover;

controlling the power to the prime mover with a controller;

sensing operating characteristics of the pumping system with at least one sensor;

transmitting an electrical first signal from the at least one sensor to a first signal converter;

converting the electrical first signal to an optical second signal;

transmitting the optical second signal to a second signal converter through a first fiber optic cable;

converting the optical second signal to an electrical third signal;

processing the electrical third signal and outputting an electrical fourth signal to a third signal converter;

converting the electrical fourth signal to an optical fifth signal;

transmitting the optical fifth signal through one of the first fiber optic cable and a second fiber optic cable;

converting the optical fifth signal to an electrical sixth signal;

amplifying the electrical sixth signal to generate an amplified electrical seventh signal; and

transmitting the amplified electrical seventh signal to regulate the controller.

15. The method of controlling the prime mover as defined in claim 14, further comprising:

providing a high voltage AC power source;

normally transmitting the high voltage AC power to the prime mover through a selectively operable motor contactor to control the power to the prime mover;

controlling a motor relay in response to the electrical seventh signal; and

transmitting an electrical eighth signal from the motor relay to selectively operate the selectively operable motor contactor.

16. The method of controlling the prime mover as defined in claim 15, further comprising:

transforming a portion of the high voltage AC power to a low voltage AC power with at least one transformer.

17. The method of controlling the prime mover as defined in claim 16, further comprising:

rectifying a portion of the low voltage AC power to provide a first substantially DC current to drive an oscillator;

generating a second substantially AC current with the oscillator to drive an electrical isolation transformer; and

rectifying the second substantially AC current to provide substantially DC current to the at least one sensor.

18. The method of controlling the prime mover as defined in claim 17, further comprising:

regulating voltage to the oscillator; and

regulating voltage to the electrical isolation transformer.

19. The method of controlling the prime mover as defined in claim 14, further comprising:

transforming the high voltage AC power to a medium AC voltage source; and

transforming the medium AC voltage source to the low AC voltage source.

20. The method of controlling the prime mover as defined in claim 14, further comprising:

providing lightning and transient voltage and current protection electrically between the high voltage AC power source and a high voltage side of at least one transformer.

21. The method of controlling the prime mover as defined in claim 14, further comprising:

powering a pump-off controller for processing the third electrical signal with a solar panel.

22. The method of controlling the prime mover as defined in claim 16, further comprising:

powering a pump-off controller for processing the third electrical signal with the low voltage AC power.