AU2021221424A1 - Electrical Safety Hazard Identification And Warning System - Google Patents

Abstract

A ground probe electrical safety system comprising a primary device; a probe device; the primary device including a processor, a voltage differential sensor and an alarm communications; the probe device comprising an electrically conductive probe housed within an insulating sheath structure; a distal portion of the probe extending from the insulating sheath structure for embedding in the ground; the electrically conductive probe electrically connected by electrically conductive, flexible cable to the voltage differential sensor of the primary device; in use the distal portion of the probe embedded in the ground conducting a voltage signal via the electrically conductive, flexible cable to the voltage differential sensor of the primary device; the primary device communicating an alarm condition if the voltage signal has a magnitude greater than a predetermined value compared with a ground reference. 1/3 (I) LU - = u U <J< -F LU 0 ~LU 00U 0 LU o- LU) U*) c-)< C) LU< 0 zz LUU LU L -J-J LU L V) + LL cuj u j ; w U - < a- _j LUV) co 0 zz LUU LU --o 00 o 0j a.

Description

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ELECTRICAL SAFETY HAZARD IDENTIFICATION AND WARNING SYSTEM TECHNICAL FIELD

[0001] The present invention relates to an electrical safety hazard identification system and more particularly but not exclusively to such a system which identifies hazardous voltage potentials in installations in the ground and even more particularly although not exclusively to such a system which identifies hazardous voltage gradients or touch potentials in plumbing installations located in the ground. In particular instances the system can also provide a warning when electrical safety hazards of prescribed types are identified.

BACKGROUND

[0002] Touch potentials can exist in or near the ground surface between points spaced apart in or near the ground surface. For example voltage gradients are known associated with powerline installations which can, for example, be hazardous to animals walking on the ground surface experiencing such voltage gradients where they may touch simultaneously two locations spaced apart from each other between which a voltage gradient exists.

[0003] Voltage gradients in the ground can also occur as a result of fault conditions in electrical infrastructure located near or mounted upon or indeed connected to or located in the ground in question.

[0004] Voltage gradients can be a particular problem where plumbing installations are concerned-for example in situations where electrically conductive pipework is buried in the ground or supported on the ground.

[0005] It is not unknown, for example, that parts of the electrical supply system are electrically connected to the conductive pipework-for example where the conductive pipework, because it is at least partially buried in the ground, is used as a ground reference point for the electrical supply system.

[0006] In instances where plumbing installations are disturbed-for example by cutting electrically conductive pipework so as to separate one portion of the pipework from another the action of disturbing the plumbing installation may give rise to increased and in some cases hazardous touch potentials between different locations in the plumbing installation.

[0007] It has been known for plumbers to enlist the aid of qualified electricians who are qualified to use voltmeters and like electrical testing equipment to explore for potentially hazardous touch potentials in a work area. However this approach delays commencement of work and as to costs of carrying out the work for the plumber.

[0008] Problems arising from these observations include:

(1) identification of the existence of hazardous voltage gradients or touch potentials;

(2) warning given that hazardous voltage gradients or touch potentials exist in or near where someone is working;

(3) needing a qualified electrician to explore for hazardous touch potentials preparatory to commencing work.

[0009] It is an object of the present invention to provide a system and components therefor which seek to address or ameliorate one or more of the above-mentioned problems.

NOTES

[0010] The term "comprising" (and grammatical variations thereof) is used in this specification in the inclusive sense of "having" or "including", and not in the exclusive sense of "consisting only of'.

[0011] The above discussion of the prior art in the Background of the invention, is not an admission that any information discussed therein is citable prior art or part of the common general knowledge of persons skilled in the art in any country.

SUMMARY OF INVENTION

[0012] According to one broad form of the invention, there is provided a ground probe electrical safety system that comprises:

a primary device; a probe device; the primary device including a processor, a voltage differential sensor and an alarm communications; the probe device comprising an electrically conductive probe housed within an insulating sheath structure; a distal portion of the probe extending from the insulating sheath structure for embedding in the ground; the electrically conductive probe electrically connected by electrically conductive, flexible cable to the voltage differential sensor of the primary device; in use the distal portion of the probe embedded in the ground conducting a voltage signal via the electrically conductive, flexible cable to the voltage differential sensor of the primary device; the primary device communicating an alarm condition if the voltage signal has a magnitude greater than a predetermined value compared with a ground reference.

[0013] Preferably, the ground reference comprises a separate probe embedded in the ground at a predetermined distance from a point of embedment of the probe device; the separate probe electrically connected to the voltage differential sensor.

[0014] Preferably, the predetermined distance is at least 2 m.

[0015] Preferably, the probe device and the separate probe are releasably, electrically connected to an input circuit of the primary device which then communicates the voltage signal to the processor.

[0016] Preferably, the input circuit includes an electrical filter.

[0017] Preferably, the input circuit includes a rectifier.

[0018] Preferably, the primary device includes a selector for selecting between a first predetermined pre-set voltage value and a second predetermined pre-set voltage value.

[0019] Preferably, the first predetermined pre-set voltage value is 6 V.

[0020] Preferably, the second predetermined pre-set voltage value is 3 V.

[0021] According to another broad form of the invention, there is provided a ground voltage probe in combination with a voltage differential sensor and alarm unit; the voltage differential sensor and alarm unit that comprises: an input circuit in communication with a processor; the input circuit connecting a voltage magnitude signal to the processor; the processor outputting an alarm signal if the voltage magnitude signal is greater than a predetermined magnitude.

[0022] Preferably, the ground voltage probe comprises an electrically conductive probe housed within an insulating sheath structure; a distal portion of the probe extending from the insulating sheath structure for embedding in the ground; the electrically conductive probe electrically connected by electrically conductive, flexible cable to the voltage differential sensor.

[0023] According to another broad form of the invention, there is provided a method of comparing magnitude of a voltage signal against a reference value; the voltage signal comprising the difference between a first earth point and a second earth point.

[0024] According to another broad form of the invention, there is provided a method of comparing magnitude of a voltage signal against a reference value; the voltage signal comprising the difference between a first earth point and a pipe portion; the pipe portion located in or connected to the ground.

[0025] According to another broad form of the invention, there is provided a method of comparing magnitude of a voltage signal against a reference value; the voltage signal comprising the difference between a first pipe portion and a second pipe portion; the first pipe portion and the second pipe portion separately located in or connected to the ground.

[0026] According to another broad form of the invention, there is provided a probe device comprising an electrically conductive probe housed within an insulating sheath structure; a distal portion of the probe extending from the insulating sheath structure for embedding in the ground; the electrically conductive probe electrically connectable by electrically conductive, flexible cable to a voltage differential sensor of a primary device; in use the distal portion of the probe embedded in the ground conducting a voltage signal via the electrically conductive, flexible cable to the voltage differential sensor of the primary device; the primary device communicating an alarm condition if the voltage signal has a magnitude greater than a predetermined value compared with a ground reference.

[0027] Preferably, a crossbar is located relatively low down on a probe portion which may assist a user in exerting downward pressure on the ground probe so as to drive the far end of the probe portion into the ground.

[0028] Preferably, the system incorporates a lead off sensor whereby an alarm condition is signalled in the event that all leads do not remain connected during use of the system.

BRIEF DESCRIPTION OF DRAWINGS

[0029] Embodiments of the present invention will be described with reference to the accompanying drawings wherein:

[0030] Figure 1 is a block diagram of a voltage differential sensor and alarm unit according to a first embodiment and having a primary device with a probe device in flexible electrical communication therewith;

[0031] Figure 2 illustrates a first mode of connection of probe devices to the primary device.

[0032] Figure 3 illustrates a second mode of connection of a probe device to the primary device.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0033] With reference to figure 1 there is illustrated in block diagram form a voltage differential sensor and alarm unit 12 in accordance with a first embodiment of the present invention. In this instance the voltage differential sensor and alarm unit 12 is in flexible electrical communication with a probe 13. Together, in operation, they form a system 10 for electrical safety hazard identification and warning.

[0034] In this instance the probe 13 is in the form of a ground probe 13A in flexible electrical communication with primary unit 12 A of the voltage differential sensor and alarm unit according to a second mode of operation of the voltage differential sensor and alarm unit 12.

[0035] The primary device 12 A includes an input circuit 15 in electrical communication with a processor 16 by which a voltage signal 17 is passed to the processor 16.

[0036] The processor 16 includes what logic for determination of the magnitude of the voltage signal 17. The processor 16 further includes logic for comparing the magnitude of the voltage signal 17 against a reference value t 18 stored in memory 19.

[0037] In the event that the voltage signal 17 exceeds the reference value 18 then the microprocessor 16 communicates with an alarm communications system 21 which, in this instance, comprises local audible and visual alarms 21A and external communications module 20 1B in assistance in the form of a Bluetooth communications device whereby an alarm signal can be sent to a portable digital device such as a smart phone 22.

[0038] In preferred forms the reference value 18 is 6 V. Preferably the reference value 18 lies in the range 10 V to 2 V in magnitude. In a preferred form the reference value 18 is set to a pre-set value. In a particular preferred form the pre-set value is 6 V. In a further particular preferred form a second pre-set value 18B is stored in memory 19 as a 'high sensitivity' value. In preferred forms the high sensitivity pre-set value is 3 V.

[0039] In particular preferred forms a user may select via selector 31 on the primary device 12A between the first pre-set and second pre-set value.

[0040] With reference to figure 3 there is illustrated a ground probe 13A in accordance with a preferred embodiment. In a preferred form the ground probe 13A includes a rod-like probe portion 23 extending from an electrically insulated housing 24. In a particular preferred form a crossbar 25 is located relatively low down on the probe portion 23 which may assist a user in exerting downward pressure on the ground probe 13A so as to drive the far end 26 of the probe portion 23 into the ground 27.

[0041] The probe portion 23 is made from an electrically conductive material such as copper or aluminium. In an alternative form the probe portion 23 may be made from steel. It is in electrical communication via a flexible electrically conductive insulated wire 28 to input circuit 15 so as to provide voltage signal 17 to primary device 12A.

[0042] Also connected to input circuit 15 is ground wire 30 is illustrated in figure 3. A far end of the ground wire 30 is connected to the earth so as to provide a reference. Preferably the point of connection 30A to ground is at a distance of at least a few metres from where ground probe 13A is to be projected into ground 27. Preferably the distance is in the range 2 to 5 m. Preferably the minimum distance is 2 m. In a preferred form the distance is at least 10 m (for sizing of the electrical components in the voltage differential sensor and alarming unit 12 the earth resistance between where ground probe 13A is projected into ground 27 and the point of connection 13A of the ground wire 30 is modelled at 15 Ohms).

[0043] In particular preferred forms the primary device 12A may communicate with an application running on a portable digital device such as mobile phone 32 so as to communicate alarm conditions detected when the pre-set reference value is exceeded as calculated by processor 16 with reference to voltage signal 17 received from ground probe 13A.

[0044] Input circuit 15 includes a filter circuit 15A. In preferred forms it includes a rectifier B whereby the voltage differential sensor and alarm unit 12 may be used to detect both DC and AC ground currents and corresponding DC or AC touch potentials.

[0045] With reference to figure 2 there is illustrated in block diagram form a second mode of connection of probe devices to the primary device.

[0046] In this instance a first pipe portion 33 is electrically connected to input circuit 15 via a first probe 34.

[0047] A second pipe portion 35 is electrically connected to input circuit 15 via a second probe 36. In this instance the first pipe portion 33 and the second pipe portion 35 comprise separate pipe portions both in ground 27.

[0048] A separate ground probe 30 embedded in the ground 27 separated from pipe portions 33, 35 also connects to input circuit 15 as illustrated. In this instance the arrangement permits sensing of a first voltage differential VI and a second voltage differential V2.

Lead off sensing

[0049] With reference to figure 1 the primary device 12A may include a lead off sensing capability whereby in the event, in use, a user does not connect all three leads to the input circuit (or a lead disconnects during use) the input lines to processor 16 may be sensed via signal input 41 to differential sensor 42 whereby to cause processor 16 to generate a lead off alarm condition.

[0050] In one embodiment the differential sensor 42 may be implemented in hardware as a comparator or operational amplifier configured to operate as a comparator. In an alternative form the differential sensor 42 may be implemented in software as program code stored in memory 19 and executable by processor 16.

Claims (17)

1. CLAIMS 1. A ground probe electrical safety system comprising a primary device; a probe device; the primary device including a processor, a voltage differential sensor and an alarm communications; the probe device comprising an electrically conductive probe housed within an insulating sheath structure; a distal portion of the probe extending from the insulating sheath structure for embedding in the ground; the electrically conductive probe electrically connected by electrically conductive, flexible cable to the voltage differential sensor of the primary device; in use the distal portion of the probe embedded in the ground conducting a voltage signal via the electrically conductive, flexible cable to the voltage differential sensor of the primary device; the primary device communicating an alarm condition if the voltage signal has a magnitude greater than a predetermined value compared with a ground reference.
2. 2. The ground probe electrical safety system of claim 1 wherein the ground reference comprises a separate probe embedded in the ground at a predetermined distance from a point of embedment of the probe device; the separate probe electrically connected to the voltage differential sensor.
3. 3. The system of claim 2 wherein the predetermined distance is at least 2 m.
4. 4. The system of any one of claims 1 to 3 wherein the probe device and the separate probe are releasably, electrically connected to an input circuit of the primary device which then communicates the voltage signal to the processor.
5. 5. The system of claim 4 wherein the input circuit includes an electrical filter.
6. 6. The system of claim 5 wherein the input circuit includes a rectifier.
7. 7. The system of any preceding claim wherein the primary device includes a selector for selecting between a first predetermined pre-set voltage value and a second predetermined pre set voltage value.
8. 8. The system of claim 7 wherein the first predetermined pre-set voltage value is 6 V.
9. 9. The system of claim 7 wherein the second predetermined pre-set voltage value is 3 V.
10. 10. A ground voltage probe in combination with a voltage differential sensor and alarm unit; the voltage differential sensor and alarm unit comprising: an input circuit in communication with a processor; the input circuit connecting a voltage magnitude signal to the processor; the processor outputting an alarm signal if the voltage magnitude signal is greater than a predetermined magnitude.
11. 11. The combination of claim 10 wherein the ground voltage probe comprises an electrically conductive probe housed within an insulating sheath structure; a distal portion of the probe extending from the insulating sheath structure for embedding in the ground; the electrically conductive probe electrically connected by electrically conductive, flexible cable to the voltage differential sensor.
12. 12. A method of comparing magnitude of a voltage signal against a reference value; the voltage signal comprising the difference between a first earth point and a second earth point.
13. 13. A method of comparing magnitude of a voltage signal against a reference value; the voltage signal comprising the difference between a first earth point and a pipe portion; the pipe portion located in or connected to the ground.
14. 14. A method of comparing magnitude of a voltage signal against a reference value; the voltage signal comprising the difference between a first pipe portion and a second pipe portion; the first pipe portion and the second pipe portion separately located in or connected to the ground.
15. 15. A probe device comprising an electrically conductive probe housed within an insulating sheath structure; a distal portion of the probe extending from the insulating sheath structure for embedding in the ground; the electrically conductive probe electrically connectable by electrically conductive, flexible cable to a voltage differential sensor of a primary device; in use the distal portion of the probe embedded in the ground conducting a voltage signal via the electrically conductive, flexible cable to the voltage differential sensor of the primary device; the primary device communicating an alarm condition if the voltage signal has a magnitude greater than a predetermined value compared with a ground reference.
16. 16. The probe device of claim 15 wherein a crossbar is located relatively low down on a probe portion which may assist a user in exerting downward pressure on the ground probe so as to drive the far end of the probe portion into the ground.
17. 17. The system of any one of claim 1 to 9 incorporating a lead off sensor whereby an alarm condition is signalled in the event that all leads do not remain connected during use of the system.

    LEAD OFF SENSE 12 PWR 41 SUP 42 15 INPUT CIRCUIT 17 12A 16

    ALARM LEVEL TEST MICROPROCESSOR SELF TEST 15A GENERATOR

    M 19 WITH VOLTAGE 31 PROTECTION AUDIBLE + REFERENCE VISUAL VALUE 18 DUAL 21A ALARMS CONNECTORS PRE-SET 1 18A PRE-SET 2 1/3

    18B 13A BLUE TOOTH INSULATED 13 COMS TO APP

    FOOT PEGS 21B STEEL SPIKE INSULATED

    GROUND PROBE TO INTERNET VIA PHONE APP TO RECORD AND LOG ALL ALARMS + TESTS + POSITION 32

    Fig. 1