A METHOD AND DEVICE TO CAPTURE AND PROCESS ELECTRIC SIGNALS

Abstract: The present invention relates to a method and a device for capturing and processing electric signals with the aid of, i.a. an electric battery in order to create an impression of the risk of electric flash-over from high-tension alternating current lines to a human being (an individual). The method and device according to the invention are distinguished in that disengaged from direct electrical connections with the surroundings a measure of electric field strength in a point is measured with the aid of at least one sensing unit. This is equipped with two electric conductors with differently sized areas in relation to each other, which from the electrical point of view are isolated from each other, the said sensing unit with its smaller area always being located closer to the origin of the said field strength than its larger area. The alternating voltage generated across the said two electric conductors with different areas is then signal-processed and presented as a measure of the said risk of electric flash-over.

Description: A METHOD AND DEVICE TO CAPTURE AND PROCESS ELECTRIC SIGNALS The present invention relates to a method of capturing and processing electric signals in order to provide a relevant impression of any possible risk of electric flash-over from, primarily, high voltage alternating current lines to, primarily, a human being and a device for carrying out the method. The ability to sense witii the aid of different kinds of meters the field strength of electrical alternating currents for the primary purpose of demonstrating electrical risks to human beings is known in the art through for example Swedish patent No. 411 080. Detection from vehicles or other objects of proximity to electric power lines in order to reduce the risk of injury in the form of electric shocks transmitted to individuals driving said vehicles or located in the vicinity of said vehicles is also known in the art through i.a. European patents No. 0 134 943, No. 0 266 883 and No. 0 324 217. Most of the known field-strength meters of the aforesaid known type are by virtue of their functional designs and constructive elaboration bulky in size and weight and consequently are highly unsuitable for use as a personal protection intended for personal use, which presupposes - for more general acceptance and use - simple and rapid application relative to the individual concerned, compact dimensions and low weight etc. A further disadvantage inherent in several of the known field- strength metres is that the constructive elaboration assumes sensing of electric current in one form or another. Such field-strength meters also suffer additionally from the disadvantage ύiat if the alternating current conductors or lines that generate the electric fields which are potentially dangerous for an individual has a high capacitance in relation to the known field-strength meters, the latter will not always function in the intended manner. Moreover certain known field strength meters require some form of external grounding in order to be able to provide correct values for the field strength in a given point and are also extremely sensitive to the direction of the electric field, so that if, for example, the active plates of a known field- strength meter are inadvertently placed incorrectly in relation to the direction of the electric field, misleading measurement values are generated. The function of the field-strength meter according to Swedish patent No. 411 080 imposes a requirement for two identically equally large electrodes - to be able to generate equal charges with different signs - and also requires a handle that is isolated from the Z operator. This handle must additionally be provided with swing axles and be weight-arranged to permit rotary switching in order to attain a correct setting in relation to the direction of die electric field which is to be measured. Finally this known field-strength meter also assumes that an electrostatic screen protects the included electronics. The known system for measurement of electric fields according to WO 97/09627 describes how unwanted low-frequency electric fields generated by electronic apparatus can be measured, but this system is not adapted to be able to serve as personal protection or to be able to act in environments where high-tension alternating current lines or conductors are present. The object of the present invention is to eliminate or reduce the disadvantages described above and other disadvantages associated with the known solutions and has been elaborated according to the method mentioned in the descriptive preamble so that disengaged from direct electrical connections with the surroimdings, a measurement of electric field strength is sensed in a point by means of at least one sensing unit which is equipped with two electric conductors with differendy sized areas in relation to each other which electric conductors from the electrical point of view are isolated from each otiier, die said sensing unit with its smaller area tiien always being located closer to die origin of die said field strength than its larger area, and an alternating voltage generated across the said two electric conductors with different areas is signal- processed and presented as a measure of die said risk of electric flash-over. The device according to the present invention has also, for the purpose of solving tiiese tasks, been designed with at least one sensing unit, which is fitted with two electric conductors with differendy sized areas in relation to each other. These electric conductors are from die electrical point of view insulated from each other by means of an isolating layer, the said sensing unit with its smaller area tiien being located closer to die origin of the said field strength than its larger area, and an alternating voltage generated across the said two electric conductors is signal-processed with the aid of adapted electronic circuits and then presented as a measurement of the said risk of electric flash-over. Further details of the invention will be evident from the subsequent Claims and from the description below of one embodiment of die invention chosen by way of example. The invention is described in greater detail hereinafter with reference to the accompanying drawings, of which Fig. 1 shows a perspective view of one embodiment of a reception unit chosen by way of example, Fig. 2 shows an equivalent circuit, from an electrical point of view, for the reception unit according to Fig. 1, Fig. 3 shows a block diagram chosen by way of example of an exemplified measuring and indicator unit to which the reception unit according to Fig. 1 is connected in accordance witii the present invention, and Fig. 4-10 show wiring diagrams chosen by way of example of different electric connections included in die said measuring and indicator unit according to the present invention, die details of which will be dealt with more closely in connection witii the description of tiieir main tasks. The reception unit shown in Fig. 1 includes as fundamental details a first electrically conductive surface lc - for example a thin, flexible copper strip - with a certain surface or area, a second electrically conductive area 2c with a certain larger surface or area in relation to die first electrically conductive area - for example approximately twice as large and consisting of a thin, flexible copper strip - and an appropriately flexible electric isolator 3c located between these two electrically conductive surfaces lc and 2c, which electric isolator consequendy from the electrical point of view isolate and separate - for example by 6-10 mm but the more the better - the said electrically conductive, differendy sized surfaces lc and 2c. The latter two surfaces lc and 2c are so located that the surface lc, which is smaller in size, always faces towards and the surface 2c which is larger in size always faces away from a preferably high-tension alternating current source, die potential risk of which for generating electrical flash-over in a point to an individual or possibly to an object it is intended to be determined and evaluated with the aid of the present invention. Potential field directions are indicated with unbroken arrows in Fig. 1. The first electrically conductive surface lc, the second electrically conductive surface 2 c and the insulating layer 3 c may per se consist of flexible straps which can be shaped into an essentially ring-shaped - or shaped into part of a ring - openable and closable unit so as to be able to be applied advantageously around protruding parts of an individual such as ankles or wrists, for example in a corresponding way to that in which a watch strap can be applied around a wrist with the aid of buckles, Velcro strips, adjustable links etc. Shown in Fig. 1, however, as a further example, is a third embodiment, in which the reception unit consists of a plurahty of essentially identical parts, which are articulated jointed in relation to each other, appropriately via the end edges of the isolating layers 3a, 3b, 3c, 3d, and which from an electrical point of view are each per se connected in series, with the electric conductors with a small area la, lb, lc, Id, le connected in series each per se via, appropriately, articulated jointed links 5a-5d, and with die electric conductors with a large area 2a, 2b, 2c, 2d, 2e being connected in series each per se via appropriately articulated jointed links 6a, 6b, 6c, 6d. In addition preferably the outer isolating layers 3a and 3f are mechanically connected togedier by means of mutually overlapping adjustment straps 4a, 4b, which in die present case are fitted with, for example, Velcro straps with which they can be mechanically connected together in relation to one another, whereby - as is evident from Fig. 1 - die aperture of the reception unit can be adjusted for different sizes of, for example, the ankles or wrists or otiier protruding parts which are to be furnished witii the reception unit or units in accordance with the present invention. Illustrated by Fig. 2 is die electrical equivalence circuit for the reception unit according to Fig. 1. This equivalent electric circuit includes a capacitance 7 with a relatively low value, which comprises the capacitance of the electric conductor 1 with a small area in relation to the ambient air surrounding the electric conductor 1 with the small area. It is further assumed in this exemplified case that an individual is carrying die reception unit according to Fig. 1 around his one wrist witii the electric conductor 2 witii the large area facing towards he wrist. The capacitance existing between the body of the individual in question and the electric conductor 2 with a large area is designated 8 in Fig. 2 and has a capacitance that is appreciably larger than the capacitance of the electric conductor 1 with a small area in relation to the ambient air. Certain variations may occur from individual to individual and also depend on the capacitance of the individual in question or his capaάtive connection to ground or earth - wet ground etc - but practical tests demonstrate tiiat this parameter has little influence on the result of die measurement. The reference of die reception unit is designated 9b in Fig. 3 and is chosen to comprise the actual potential of the electric conductor 2 with large area and a signal is designated 9a with a varying voltage in relation essentially to the electric field strength in question in the point of measurement for the electric conductor 1 with small area. The reference 9b and the varying voltage 9a are signal-processed after having been captured and are fed for this purpose according to Fig. 3 at 9 - which may per se by way of example consist of two connection pins (not shown in the drawings) to die electric conductor 1 with small area of the reception unit and electric conductor 2 with large area to a protection 10. This protection 10 is utilised in principle for die reason that the signal 9a entering on the electric conductor 1 with small area can contain severe disturbances of different kinds, from which disturbances the subsequent signal-processing electronics must be protected. A general feature of die protection 10 - as is illustrated more closely by die left hand part of Fig. 4 - is that die signal 9a is conducted tiirough an inductance 10a of, for example, 4.7 μH, connected in series witii a resistance 10b of, for example, 1 mΩ, overtones to the said signal 9b tiien being disconnected via a zener diode 10c of, for example, type BZW060, whereby any transients across the zener diode 10c are connected to the ground of the circuit. The protection 10 also includes - as is particularly evident from Fig. 4 - a circuit which acts in principle as a low-pass filter and which can include a resistance lOd of, for example, 1 mΩ, a capacitor lOe of, for example, 1 nF connected to the ground of the circuit and a capacitor of, for example, 1 nF conducting the signal on to a further circuit which acts in principle as a high-pass filter and which may include a resistance llg of, for example, 10 mΩ connected to the ground of the circuit, a capacitor llh of, for example, 1 nF passing the signal on to a point of connection between the positive input to an operation amplifier 13 of, for example, type LMC6482 and a resistance Hi of, for example, 10 mΩ, to the other end of which a second reference voltage 12, as indicated more closely hereinbelow, is connected. The said second reference voltage 12 is connected via a resistance 14a of, for example, 10 kΩ connected partly to the negative input of the operation amplifier 13 and partiy to one stationary end of an adjustable resistance 15a of 100 kΩ, the other stationary end and variable part of which variable resistance are interconnected and connected to the output 13a of the operation amplifier 13. Connected after the protection 10 is a sharp band pass-filter 16 - see especially Fig. 3 and Fig. 5. - for a mains frequency of, for example, 50 Hz, to which output 13a of die operation amplifier 13 is connected, see especially Fig. 5. The said band-pass filter 16 includes a resistance 16a of, for example, 47 kΩ connected in series with the output 13 a of the operation amplifier 13, die other end of its resistance 16a is connected together with a jimction point between a capacitor 16b of, for example, 10 nF, the other end of which is connected to d e ground of die circuit and a capacitor 16c of, for example, 10 nF, the other end of which is connected to a junction point between a resistance 16d of, for example, 56 kΩ and a capacitor 16e of, for example, 10 nF. The other end of die capacitor 16e is connected to die positive input of an operation amplifier 16g of, for example, type LMC6482, to which the second reference voltage 12 is also connected via a resistance 16f of, for example, 1,8 kΩ. The other end of the resistance 16d is connected to the negative input of the operation amplifier 16g and to its output 16h. The signal is thus processed after having been captured in the reception unit according to Fig. 1 in order to sort away unimportant and/or irrelevant information through the above mentioned protection 10 and band-pass filter 16. For one thing, high frequencies are damped out and for another thing direct voltage is filtered off, whereby the influence from high-frequency radiation sources is eliminated, for example from radio and telephone traffic, light arcs, corona discharges etc. Connected after the band-pass filter 16 is an amplifier 17 with its amplification factor setting engaged - see Fig. 3 and especially Fig. 6 for closer details. The amplifier 17 includes a resistance 17a of, for example, 10 kΩ, to one end of which output 16h from the band-pass filter 16 is connected and the other end of which is connected to the negative input of an operation amplifier 17d of type LMC6482, to which there are also connected two resistances 17b and 17c of, for example, 56kΩ and 12 kΩ, respectively, with which die other end of die latter one end of a toggle switch 17e, commercially designated, for example, SPDT and acting as a measuring range switch - which can, for example, change the measuring range by a factor of six - is connected in series, whereafter the other end of die resistance 17b and die otiier end of die toggle switch 17e are connected togetiier with output 17f of the operation amplifier 17d. The positive input of the operation amplified is also connected to the second reference voltage 12. A portable battery 21 - see especially Fig. 10 - of, for example type 3.6 V litiiium with a capacity of 2100 mAh supplies the device with the necessary feed energy via a toggle switch 2 Id, commercially designated, for example, SPDT, which toggle switch 2 Id in the activated state feeds a positive voltage from the battery 21a to an output 21e, across which two capacitors 21b and 12c are connected, each of die said capacitors 21b and 12c having a capacitance of 10 μF. This output 21e is in turn connected to several points in other Figures 7-8, all of which points are designated 21e in the respective Figures. Shown in Fig. 9 is a further part of a voltage feed where die second reference voltage 12 is supplied via a connection point which includes a resistance of, for example, 1 kΩ, connected together with a capacitor 21g of, for example, 10 μF, the other end of which is connected to the ground of die circuit. The other end of the resistance 2 If is connected to short-circuited inputs 6 and 7 of an LED drive circuit 18k of, for example, type LM3419 and in addition a resistance inputs 6 (RHI) and 7 (RFF) of the drive circuit 18k for the light emitting diodes. The output 17 - see especially Fig. 6 - is also connected to one end of a resistance 18b of, for example, 10 kΩ - see especially the left hand part of Fig. 7. The second reference voltage 12 is also connected to one side of a resistance 18a of, for example, 10 mΩ, the other end of which is connected to input 9 of the said operation amplifier, and the otiier end of die resistance 18b is connected to input 10 of die said operation amplifier 13, to which a resistance 18c of, for example, 10 kΩ is also connected. The input 11 of the operation amplifier 13 is connected to the ground of the circuit and connection 4 of die operation amplifier 13 is connected to output 21e - see especially Fig. 10. The output 8 of die operation amplifier 13 is connected to the plus side of a diode 18f of, for example, type IN4181, while the negative side of the diode 18f is connected via a resistance 18g of, for example, 10 kΩ to an output 18j, to which output 21e is also connected via a resistance 18h of 2.2 mΩ and to which output 18j there is also connected a capacitor 18i of, say, 10 μF, the other end of which is connected to the ground of die circuit. A resistance 18e of, for example, 10 mΩ is additionally connected between connection 9 of the operation amplifier and output 18j. The signal is tiius converted and measured by the converter 18, which decides which of the LED diodes 20a-20e shall be lit. The higher the input signal the larger the number of LED diodes that will be lit and die LED stack 20a-20e is driven by the LED driver 18k. As is furtiier evident from, especially, Fig. 8 die last mentioned output 18j is connected to connection 5 (SIG) of the LED driver 18k. The output 21e is also connected to inputs 9 (MODE) and 3 (V+) of the LED driver 18k. Connections 8 (ADJ), 4 (RLO) and 2 (v-) of the LED driver are all connected to the ground of the circuit. Connections 12, 14, 16, 18 and 1 of die LED driver are each connected to LED diodes 20a, 20b, 20c, 20d and 20e, respectively, each of which is of, for example, type LTL353CKH4 red 1000 mcd. Also connected to die diodes 20a, 20b, 20c and 20d via conductors 4, 3, 2, 1 according to die right hand part of Fig. 8 is an acoustic alarm 19, which includes a switch 19f of, for example, type BCD DRR4010. The latter is arranged, via a resistance 19d of, for example, 3.3 kΩ, to steer out a transistor 19a of, for example, type PNP BC327 to drive, via a resistance 19b of, for example, 47Ω, a buzzer 19b of, for example, type MEB-12C-5. The output 21e is also connected to the output of the switch 19f via a resistancel9e of, for example, 10 kΩ. The sound signal of the buzzer 19c can be set, for example, to sound when a certain LED diode (out of, for example, 4) is lit to indicate that a certain sensing level has been exceeded. The invention is obviously not restricted to the embodiment example described above but only by the accompanying patent Claims, die contents of which naturally are also embraced by and included in die description.

Claims: CLAIMS 1. A method for capturing and processing electric signals in order to provide a relevant impression of possible risks of electric flash-over from, primarily, high-tension alternating current lines to, primarily, a human being, characterized in that disengaged from direct electrical connections with die surroimdings a measure of electric field strength in a point is measured by means of at least one sensing unit which is equipped with two electric conductors witii differendy sized areas in relation to each other, which from the electrical point of view are isolated from each other, the said sensing unit with its smaller area then always being located closer to die origin of the said field strength than its larger area, and in that an alternating voltage generated across the said two electric conductors with different areas is signal- processed and presented as a measure of the said risk of electric flash-over. 2. A method as claimed in Claim 1, characterized in that two capacitances with two essentially different charging capacities in relation to each other are created by means of a first capacitive connection of the said conductor with a smaller area to the said one point in the surroundings and by means of a second capacitive connection of the said conductor with a larger area to an individual or possibly to an object which is in direct or indirect contact with the same, whereupon the first capacitive connection has a low capacitance and the second connection has a high capacitance, and in that variations in the charge of the said capacitances are compared and used as a measure of the said risk of electric flash-over. 3. A method as claimed in Claim 1 or Claim 2, characterized in that the said conductors are located largely concentrically at a mutual distance at least as a part of a ring. 4. A method as claimed in any one of Claims 1-3 , characterized in that two or more sensing units are utilised, which are located in different directions in relation to each other and whose electric conductors with different areas are each connected in series, whereby from the functional point of view two electric conductors with different areas and isolated from each otiier are retained. 5. Device for capturing and processing electric signals, with the aid of i.a. an electric battery and a signal processing unit and disengaged from direct electrical connections with the surroundings, in order to provide a relevant impression of any possible risk of electric flash-over from, primarily, high-tension alternating current lines or conductors to, primarily, an individual for carrying out die method according to Claim 1, characterized in that at least one sensing unit (1-3) which is equipped witii two electric conductors (lc, 2c; etc) witii differently sized areas in relation to each other, which from electrical point of view are isolated in relation to each other by means of an isolating layer (3c;), whereupon the said sensing unit witii its smaller area ( lc;) is located closer to die origin of the said field strength than its larger area, and in that alternating voltage generated across die said two electric conductors (lc, 2c; etc) is signal-processed with the aid of adapted electric circuits and subsequendy presented as a measure of die said risk of electric flash-over. 6. Device as claimed in Claim 5, characterized in that two or more sensing units (lc, 2c, 3c; lb, 2b, 3b; 1, 2a, 3a; etc) which are located in different directions in relation to one another and whose electric conductors with different areas are each per se connected in series, whereby from the functional point of view two electric conductors isolated from each other are retained. 7. Device as claimed in Claim 5 or Claim 6, characterized in that the said sensing unit (lc, 2c, 3c) and said sensing units ( la-3a; lb-3b; etc), respectively, are interconnectable into an essentially ring-shaped unit by means of detachable adjustment straps (4a, 4b) which, for example, are fitted with interacting means which lock the straps together upon contact. 8. Device as claimed in any one of the preceding Claims, characterized in that the signal processing of the signals captured by the said sensing unit(s) includes a protection ( 10) against electrical disturbances and, respectively, against such electric signals that lack interest in the context, an amplifier (17), preferably with a facility for selecting amplification factor, and a signal and, in appropriate cases, alarm reproducing device (18-20).

Inventors: ASSAI DANIEL, ASSAI, DANIEL
Applicants: ASSAI DANIEL, EP INTERNATIONAL AB, ASSAI, DANIEL
Application year: 1998
Main classification: G01R29
IPC codes: G01R29