Line break detection system

• US 9,983,250 B2
• Filed: 04/01/2014
• Issued: 05/29/2018
• Est. Priority Date: 10/31/2013
• Status: Expired due to Fees

• Current Assignee: Nexans Incorporated (Nokia Corporation)
• Original Assignee: Nexans Incorporated (Nokia Corporation)
• Inventors: Barber, Kenneth Willis, Lee, Michael, Fouche, Gilles
• Primary Examiner(s): Tan, Richard
• Application Number:
  US14/242,271
• Publication Number:
  US 20150115742A1
• Time in Patent Office: 1,519 Days
• Field of Search: 324500, 324509, 324512, 324527, 324528, 324533, 324534, 307125
• CPC Class Codes: G01R 31/52 Testing for short-circuits, leakage current or ground faults
• CPC Class Codes: G01R 31/54 Testing for continuity
• CPC Class Codes: G01R 31/58 Testing of lines, cables or conductors testing of electric windings G01R31/72
• CPC Class Codes: H02H 1/003 Fault detection by injection of an auxiliary voltage same for detection of earth fault currents H02H3/17; for monitoring earth connection H02H5/105

Abstract

A line break detection system for detecting a break in a conductor (1.004), the system including a first return signal generator (1.020) proximate a first end of a segment of the conductor, the first return signal generator being adapted to apply a first return signal to the conductor, the system including a first return signal detector (1.016) proximate a second end of the segment of the line, the second end being upstream of the first end, the first detector being adapted to receive the first return signal from the line, wherein the first return signal generator ceases to generate the first return signal if the line is broken.

Claims

1. A method of detecting a break or short circuit on a section of a power supply line, said method comprising steps of:

injecting a return signal at a downstream end of the section of the power supply line with a power supply line fault detection return signal generator (return signal generator) including a power supply, power for the return signal generator being derived from a medium voltage line via a coupling capacitor and a choke coil through which a main frequency power is delivered to the power supply, a bitstream generator generates the return signal generator'"'"'s characteristic bitstream and applies it to a modulator,

a line driver receiving a modulated signal and applies it to the coupling capacitor, said coupling capacitor connects an output of the line driver to the medium voltage line; and

detecting the return signal at an upstream end of the section of the power supply line with a power supply line fault detection return signal detector (return signal detector), said return signal detector including a transformer supplying power to the return signal detector and a relay that is coupled to a return signal detector controller, the return signal detector using a capacitor to capture the return signal on the power supply line and an amplifier to provide an amplified return signal to a demodulator which in turn delivers a demodulated return signal to signal processing means.

2. The method of detecting the break or short circuit as claimed in claim 1, including a step of removing power from the section of the power supply line in an event of failure to detect the return signal at the upstream end of the section.

3. The method of detecting the break or short circuit as claimed in claim 1, wherein said return signal generator:

generates the return signal; and

applies the return signal to the power supply line.

4. The method of detecting the break or short circuit as claimed in claim 1, wherein said return signal detector:

receives the return signal from the power supply line;

analyses the return signal; and

produces a power line control signal in response to a presence or an absence of the return signal.

5. The method of detecting the break or short circuit as claimed in claim 4, wherein said return signal detector further includes a power interruption breaker switch to remove power from the power supply line in response to the detection of an absence of a return signal.

6. The method of detecting the break or short circuit as claimed in claim 3, further implements a return signal repeater including a return signal detection means that has

a return signal detection coupling capacitor,

an amplifier,

a demodulator, and a controller,

adapted to detect return signals from the return signal generator, and

a return signal regeneration means that has

a modulator,

a line driver and a return signal regeneration coupling capacitor.

7. The method of detecting the break or short circuit as claimed in claim 3, further comprising a return signal concentrator comprising:

return signal detection means adapted to detect and distinguish two or more return signals from two or more return signal generators; and

a return signal regeneration means adapted to produce a concentrated return signal.

8. The method of detecting the break or short circuit as claimed in claim 7, wherein

the concentrated return signal is adapted to indicate a presence or an absence of each of the two or more return signals from the two or more return signal generators.

9. The method of detecting the break or short circuit as claimed in claim 4, said method employing either at least one return signal generator or a plurality of return signal generators wherein said at least one of the return signal generators;

generates the return signal and applies the return signal to the power supply line, where each return signal generator is adapted to generate a characteristic return signal which is applied to the power supply line, and

said method employing either at least one return signal detector or a plurality of return signal detectors, wherein the return signal detector connected to the power supply line upstream of the at least one or each return signal generator detects the return signal to confirm continuity of the power supply line, and, in the absence of the return signal, generates a fault signal.

10. The method of detecting the break or short circuit as claimed in claim 9, further comprising a first breaker switch, the return signal detector being adapted to operate the first breaker switch to isolate the power supply line from a source of electrical power when the return signal detector detects the absence of the return signal.

11. The method of detecting the break or short circuit as claimed in claim 9, wherein the return signal detector is adapted to associate each characteristic return signal with a corresponding one of said return signal generators.

12. The method of detecting the break or short circuit as claimed in claim 9, further comprising a return signal concentrator, adapted to receive return signals from two or more downstream return signal generators, and to generate a concentrated return signal for transmission to the return signal detector.

13. The method of detecting the break or short circuit as claimed in claim 9, further comprising a branch line including a branch line return signal generator located at a distance from a junction of a second branch line, the branch line return signal generator generating a characteristic return signal associated with the branch line return signal generator, the system including a branch line return signal detector located on the branch line near the junction of the second branch line, the branch line return signal detector being adapted to detect the characteristic return signal from the branch line return signal generator.

14. The method of detecting the break or short circuit as claimed in claim 13, further comprising a breaker switch adapted to disconnect the branch line from a source of electrical power in response to a control output from the branch line return signal detector.

15. The method of detecting the break or short circuit as claimed in claim 9, wherein the at least one of or each return signal generator or a signal concentrator includes a back-up power supply to enable the return signal generator to continue to transmit a characteristic return signal in an event of loss of power from the power supply line.

16. The method of detecting the break or short circuit as claimed in claim 14, wherein the return signal detector is adapted to receive return signals after the breaker switch has opened, and, in an event of reception of the return signal which had been temporarily interrupted, to close the breaker switch.

17. The method of detecting the break or short circuit as claimed in claim 4, wherein said method includes a monitoring system monitoring a segment of the power supply line,

wherein the return signal generator generates the return signal and transmits the return signal to the return signal detector, to indicate a presence or an absence of a supply voltage at the downstream end of the section of the power supply line.

18. The method of detecting the break or short circuit as claimed in claim 17, wherein the return signal generator transmits the return signal wirelessly.

19. The method of detecting the break or short circuit as claimed in claim 18, wherein the return signal generator transmits the return signal to the return signal detector in the absence of the supply voltage at the downstream end of the segment of the power supply line.

20. The method of detecting the break or short circuit as claimed in claim 1, wherein the return signal generator has

a line voltage detector;

a signal generator controlled by the line voltage detector to generate the return signal; and

a wireless transmitter connected to the signal generator to transmit the return signal.