Acoustic impact detection and monitoring system

• US 7,607,351 B2
• Filed: 06/26/2007
• Issued: 10/27/2009
• Est. Priority Date: 06/26/2007
• Status: Active Grant

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Chassaing, Charles E, Allison, Peter S., Lethcoe, Bryan
• Primary Examiner(s): Kwok; Helen C.
• Application Number:
  US11/819,214
• Publication Number:
  US 20090000381A1
• Time in Patent Office: 854 Days
• Field of Search: 735/92, 735/94, 73/405.A, 735/79, 735/96, 702 35- 36, 702 50- 54
• US Class Current: 73/592
• CPC Class Codes: F16L 2201/30 Detecting leaks
• CPC Class Codes: F16L 55/00 Devices or appurtenances for use in, or in connection with, pipes or pipe systems the preceding groups and groups F16L57/00, F16L59/00 take precedence; repairing or joining pipes on or under water F16L1/26; nozzles B05B; cleaning of pipes B08B9/02; arrangements of draining devices for water main or service pipe systems E03B7/08; devices for preventing bursting of water pipes by freezing E03B7/10; draining devices for hydrants E03B9/14; for domestic plumbing installations E03C1/00; steam traps for draining of liquids from enclosures containing gases or vapours F16T; arrangements for sealing leaky tubes or conduits of heat-exchangers F28F11/00
• CPC Class Codes: G01H 3/12 by electric means G01H3/14 takes precedence
• CPC Class Codes: G07C 3/08 Registering or indicating the production of the machine either with or without registering working or idle time

Abstract

A system is disclosed for detecting and locating harmful impacts to pipelines using sensors placed along the pipeline. The exact spacing of sensors is site specific and is set with the goal of maximizing sensor spacing without reducing system performance and reliability. At each sensor location, preferably there are four basic components, i.e., a hydrophone, solar power components, and data processing and communications equipment. Each hydrophone directly measures the acoustic noise fluctuation in a pipe section, which propagates at long distances in the pipeline at the specific speed of sound for the particular type of pipe. If specific signal parameters exceed a programmed threshold, a detection message is generated and transmitted via a communications link to a central monitoring and diagnostic center.

Claims

1. A system for detecting and locating impacts to a pipeline, the system comprising:

a plurality of sensors attached to the pipeline along a length of the pipeline,

a plurality of sensor stations positioned along the length of the pipeline, each sensor station corresponding to one of the plurality of sensors,

a monitoring station remote from the plurality of sensors and sensor stations, and

a bidirectional communications link between the remote monitoring station and each of the sensor stations,

each of the sensor stations performing data acquisition and signal processing functions for collecting data from the corresponding sensor and processing the data to autonomously determine whether the pipeline has been impacted and the time at which the impact occurred,

each of the sensor stations being programmed to autonomously vary its detection threshold for determining that the pipeline has been impacted.

2. The system of claim 1, wherein each of the sensors is a hydrophone that measures acoustic signals indicative of pressure fluctuations in the pipeline.

3. The system of claim 1, wherein each of the sensors is positioned along the length of the pipeline so as to maximize sensor spacing without reducing the performance capability and reliability of the monitoring system.

4. The system of claim 3, wherein the sensors are hydrophones placed about 15 km apart along the length of the pipeline.

5. The system of claim 1, wherein each of the sensor stations includes a data acquisition module for receiving data from the corresponding sensor, a data processing module for processing the data received from the corresponding sensor to determine whether an impact has occurred on the pipeline, and a communications module for communicating the impact determination to a remote monitoring center.

6. The system of claim 5, wherein the data processing module performs real time frequency discrimination to eliminate impact false alarms from non-threat acoustic sources.

7. The system of claim 5, wherein the data processing module uses a data processing technique to extract noise generated by a pipeline impact from global ambient noise in the pipeline.

8. The system of claim 7, wherein the data processing technique is a signal treatment technique that includes at least one of minimum and maximum duration constraints, frequency sensitive thresholding, and sensor sensitivity and signal gain adjustment.

9. The system of claim 5, wherein the signal processing module determines if a root mean square(“

RMS”

) amplitude of a processed data signal exceeds an autonomously determined threshold by a statistically significant amount, and, if so, wherein the communications module generates an impact detection message and transmits the message via the communications link to the remote monitoring station.

10. The system of claim 5, wherein a degree of confidence associated with a hypothesis that measured acoustic signals exceeds a predetermined threshold is specified in advance by a program setting.

11. The system of claim 9, wherein the remote monitoring station processes detection messages from multiple sensor stations to validate and localize an impact event and generate an event alarm.

12. The system of claim 11, wherein accurate localization of an impact is detected by two sensors located on opposite sides of the impact, and wherein a strike location is computed according to the formula d=[D(c−

u)−

Δ

t(c^2−

u^2)]/2c, where “

d”

is a distance of impact from a sensor nearest to the impact, “

D”

is an overall distance between two sensors on opposite sides of the impact, “

c”

is the velocity of sound inside the pipeline, “

u”

is the bulk flow velocity of the fluid in the pipe, and “

Δ

t”

is a transit time difference for the impact shock to reach the sensors on opposite sides of the impact.

13. The system of claim 5, wherein each communications module includes a satellite modem for near real time communication with the remote monitoring center and to synchronize to Global Positioning System time.

14. The system of claim 1, further comprising at least one solar panel for providing power to the sensor station and the corresponding sensor.

15. The system of claim 1, wherein each sensor is a hydrophone installed on a fixture connected to the pipeline without tapping into the pipeline.

16. The system of claim 1, wherein the bidirectional communications link includes for each sensor station a satellite modem and antenna for communication with a low earth orbit satellite.

17. The system of claim 1, wherein the remote monitoring station performs both monitoring and diagnostic functions to continuously monitor the occurrence of pipeline impacts, identify threats to the pipeline and eliminate false alarms.

23. The system of claim 1, wherein each sensor station is programmed to vary its detection threshold in response to variations in the background noise level in the pipe.

18. A system for detecting and locating strikes to a pipeline, the system comprising:

a plurality of sensors attached to the pipeline along a length of the pipeline, each of the sensors measuring acoustic noise fluctuation in the pipeline,

a plurality of sensor stations positioned along the length of the pipeline, each sensor station being linked to a corresponding one of the plurality of sensors, each of the sensor stations collecting data from the corresponding sensor and processing the data collected from the corresponding sensor to autonomously determine whether the pipeline has been impacted and the time at which the impact occurred, each of the sensor stations being programmable to vary its detection threshold for determining that the pipeline has been impacted,

a monitoring and diagnostic center remote from the plurality of sensors and sensor stations, and

a bidirectional communications link between the remote monitoring and diagnostic center and each of the sensor stations,

the monitoring and diagnostic center monitoring communications from the plurality of sensor stations for detecting pipeline strikes and calculating a position of the detected pipeline strikes that are determined to present a threat to the pipeline.

19. The system of claim 18, wherein each of the sensors is a hydrophone positioned along the length of the pipeline so as to maximize sensor spacing without reducing system performance capability and reliability, and wherein the data processing performed by each sensor station uses a data processing technique to extract noise generated by a pipeline strike from ambient noise in the pipeline.

20. The system of claim 19, wherein the remote monitoring and diagnostic center uses strike data received from two sensors located on opposite sides of a strike to determine a location of the strike, the monitoring and diagnostic center using a time difference for the strike shock to reach the two sensors on opposite sides of the strike to determine the distance of the strike from the sensor nearest to the strike.

21. A system for detecting and locating impacts to a pipeline, the system comprising:

a plurality of hydrophones attached to the pipeline along a length of the pipeline, each of the hydrophones measuring acoustic noise fluctuation in the pipeline,

a plurality of sensor stations positioned along the length of the pipeline, each sensor station being linked to a corresponding one of the plurality of hydrophones, each of the sensor stations including a communications module and data acquisition and processing modules to autonomously determine whether the pipeline has been impacted and the time at which the impact occurred, each of the processing modules being programmed to autonomously vary its detection threshold for determining that the pipeline has been impacted,

a remote monitoring and diagnostic center for receiving communications from the plurality of sensor stations indicating that the pipeline has been impacted, and

a bidirectional communications link between the remote monitoring and diagnostic center and each of the sensor stations, the bidirectional communications link including a low earth orbit satellite link,

the remote monitoring and diagnostic center determining whether the communications from the plurality of sensor stations indicating pipeline impacts are false alarms, and if not, calculating a position of a detected pipeline impact.

22. The system of claim 21, wherein each processing module processes the data from one of the corresponding sensors using dedicated algorithms that compute a Fast Fourier Transform (“

FFT”

) of the data in real time and look for changes in energy in the current data versus the previous background.

24. The system of claim 21, wherein each of the processing modules is programmed to autonomously vary its detection threshold in response to variations in the background noise level in the pipe.