GB2546142A

GB2546142A - Electric field detector

Info

Publication number: GB2546142A
Application number: GB1618805.4A
Authority: GB
Inventors: Francis Penney Richard
Original assignee: HAMPSHIRE BALLOONS Ltd
Current assignee: HAMPSHIRE BALLOONS Ltd
Priority date: 2015-11-10
Filing date: 2016-11-08
Publication date: 2017-07-12
Also published as: GB201519797D0

Abstract

An electric field detector for a hot air balloon, comprises a pair of sensors 10A, 10B each adapted to sense an electric field that is generated by electrical transmission lines, measurement means 20 to measure the potential difference between said sensors and generate a signal representative of the distance from the detector to transmission lines, and means to display 30 the signal to give an indication to a user of the distance from the detector to a transmission line, such as an audible and/or visual display(s). The display means may also provide an indication of the direction of the mains power line from the detector. The sensors may be secured to the basket of the balloon, and may be in the form of sensor plates, or a pair of spaced apart wires or antennae cables, which may be configured as loops. The measurement means 20 may have a filter, amplifier and signal conditioner. The filter centres on the mains frequency of the transmission lines e.g. 50Hz. The signal conditioner reduces the occurrence of false warnings by eliminating the effect of broadband noise from the balloons burners.

Description

Title: Electric Field Detector The present invention relates to an electric field detector.

Many people enjoy hot air ballooning. One hazard when ballooning is the presence of electricity power lines supported on pylons which if hit, can result in electrocution of the occupants of the balloon.

The invention seeks to provide a solution to this problem.

According to the present invention there is provided an electric field detector comprising: a) at least of sensors each adapted to sense the electric field in free space that is generated by mains power lines, b) measurement means to measure the potential difference between the two sensors and to generate a signal representative of the distance from the detector to a power line, and c) a display to receive the signal to give an indication of the distance from the detector to a power line.

Preferably the display means gives audible and/or visual display/s. The display means may give three indications of the distance from the detector to a power line. The display means may provide an indication of the direction of the power line from the detector.

In one embodiment the sensors are sensor plates.

In another embodiment the sensors are a pair of wires. The wires are adapted to form loops spaced apart.

Preferably the sensor plates are adapted to be secured to a balloon basket.

Preferably the measurement means includes a filter centred on mains frequency, e.g. 50Hz. The measurement means may also include an amplifier. The measurement means may further include a signal conditioner.

An embodiment of the invention will now be described with reference to the accompanying drawings in which:

Figure 1 shows a schematic circuit diagram,

Figure 2 shows a view of a display means, and

Figure 3 shows a perspective view of a balloon basket and a view of an alternative display means.

Referring to the drawings there is shown an electric field detector 1. A pair of sensor plates ΙΟΑ,ΙΟΒ are provided, each adapted to sense the electric field in free space that is generated by mains power lines. The sensor plates ΙΟΑ,ΙΟΒ are adapted to be secured to a balloon basket. A measurement means 20 is provided to measure the potential difference between the two plates in an electrostatic field provided by a power line and to generate a signal representative of the distance from the detector to a power line. The measurement means also has signal conditioner 21, filter 22, and amplifier 23. The filter 22 is centred on mains frequency, e.g. 50Hz and may include analogue and digital devices.

The flames of balloon burners are high temperature and generate large quantities of charged particles. This is seen by the electric field detector as broadband noise affecting all frequencies including mains (eg 50Hz). This may causes false warnings to be shown on the display which are unwanted and might lead to a pilot disabling or ignoring the detector. The signal conditioner is designed to eliminate the affect of this broadband noise.

The signal conditioner may operate as follows. For each measurement, the signal data representing the detected electric field is sampled using an analogue to digital converter for a period of 200ms. Then, a software algorithm evaluates the Auto-Correlation Function (ACF) of the sampled data over a range of time-shifts (denoted by Greek letter tau) corresponding to mains frequencies. The peak value of ACFs performed over the range of tau is divided by the ACF with tau = 0 to calculate a normalized quotient representing the "mains-ness" of the sampled data. If below a certain threshold, the data is reckoned to be due to burner noise and treated appropriately. A display 30 is provided to receive the signal to give an indication of the distance from the detector to a power line. Display 30 has three circles of LEDs 31 A,31 B,31C, a standby button 32 to turn the detector on and off, up and down volume control buttons 33A,33B to operate a audible signal from a speaker 34. Display unit 20 houses the measurement means 20.

In use when the detector is near a power line, one of the circles of LEDs 31A,31B,31C lights up. Circle 31A may light up when the distance from a power line represents a real hazard (e.g. 50 metres), circle 3 IB may light up when the distance from a power line represents a medium hazard (e.g. 100 metres), and circle 31C may light up when the distance from a power line represents a low hazard (e.g. 200 metres). The detector may also give out one of three different audible alarms through speaker 34 at the same time circle 31A,31B, or 31C is lit up. The audible alarms may be adjusted in volume using buttons 33A,33B.

Referring now to Figure 3, there is shown a balloon basket X with burner support poles Yl, Y2,Y3,Y4. A display unit 30 is mounted on one burner pole Y4 using strap 30A. Display 30 houses a measurement means 20 similar to that of Figure 1. Instead of plates ΙΟΑ,ΙΟΒ shown in Figure 1, a pair of antennae cables 10C,10D are used which are secured around the upper perimeter and lower perimeter of basket X into a pair of spaced loops using cable ties. Cables 10C,10D plug into display unit 30.

Display 30 is provided to receive the signal to give an indication of the distance from the detector to a power line. Display 30 has four line displays of LEDs 31, 31A (four rows of LEDs), 3 IB (three rows of LEDs), and 31C (two rows of LEDs). A standby button 32 is provided to turn the detector on and off as indicated by LED display 31, up and down volume control buttons 33A,33B to operate an audible signal from a speaker 34. Up and down control buttons also operate the sensitivity of the detector 1.

Display operates in the same way as that of Figure 2, except that display 31A lights up when the distance from a power line represents an extreme danger, display 3IB lights up when the distance from a power line represents an advanced warning, and display 31C lights up to advise “be alert”. The detector may also give out one of three different audible alarms through speaker 34 at the same time display 31 A,3 IB, or 31C is lit up. The audible alarms may be adjusted in volume using buttons 33A,33B.

The display means may provide an indication of the direction of the power line from the detector.

The invention may take a form different to that specifically described above. For example a metallic loop forming part the balloon frame could be used as part of one sensor of at least two sensors. The frame metallic loop may be connected for example to cable IOC, and cable 10D could form the other loop. More than a pair of sensors may be provided.

Further modifications will be apparent to those skilled in the art without departing from the scope of the present invention.

Claims

1. An electric field detector comprising: a) at least sensors each adapted to sense the electric field in free space that is generated by mains power lines, b) measurement means to measure the potential difference between the two sensors and to generate a signal representative of the distance from the detector to a power line, and c) a display to receive the signal to give an indication of the distance from the detector to a power line.

2. An electric field detector according to claim 1, wherein the display means gives audible and/or visual display/s.

3. An electric field detector according to claim 1 or 2, wherein the display means may give three indications of the distance from the detector to a power line.

4. An electric field detector according to claim 1,2 or 3, wherein the display means may provide an indication of the direction of the power line from the detector.

5. An electric field detector according to any preceding claim, wherein the sensors are sensor plates.

6. An electric field detector according to any of claims 1 to 4, wherein the sensors are a pair of wires or antennae cables.

7. An electric field detector according to claim 6, wherein the wires or cables are adapted to form loops spaced apart.

8. An electric field detector according to any preceding claim, wherein the sensors are adapted to be secured to a balloon basket.

9. An electric field detector according to any preceding claim, wherein the measurement means includes a filter centred on mains frequency, e.g. 50Hz.

10. An electric field detector according to any preceding claim, wherein the measurement means includes an amplifier.

11. An electric field detector according to any preceding claim, wherein the measurement means includes a signal conditioner.

12 An electric field detector according to claim 11, wherein the signal conditioner distinguishes between mains and broadband signals generated by a balloon burner.

13. An electric field detector substantially as hereinbefore described with reference to and as shown in the accompanying drawings.