RU210806U1 - Dual sensor for measuring electric field strength with multiple sensing elements - Google Patents

Abstract

The utility model relates to the field of measuring technology and can be used to measure the electric field strength in a wide spatial range with increased accuracy. is made in the form of a spherical segment with an angular size θ0, and the second pair is made in the form of a spherical layer with internal and external angular sizes, respectively, selected from the conditions θ01≥θ0 and θ02≤90°, and the sensing elements are in pairs and symmetrically located relative to the sensor surface on one coordinate axis passing through the center of the electrically conductive spherical body, while the sensitive elements and the sensor body are isolated from each other, the first sensitive elements of the corresponding pair of elements are made with the possibility of connection from the first inputs of the differential converters of the sensor output signals, and the second sensitive elements of the same pair are configured to be connected to the second inputs of the differential converters of the sensor output signals, and the outputs of the first and second differential converters of the sensor output signals, respectively, are connected to the first and second inputs of the first adder, the first input and the output of which is connected respectively to the first and second inputs of the second adder, and in the sensor the first pair of sensitive elements in the form of a spherical segment is made with angular dimensions θ0=47°, and the second pair of sensitive elements in the form of a spherical layer is made with angular dimensions at the top θ01≥ 47° and with angular dimensions at the base θ02≤90°, and the inputs of the second adder are respectively the outputs of the first and second double sensors, and its output is the output of the dual sensor. Using the proposed sensor with the optimal angular dimensions of the sensitive elements, it is possible to achieve a significant increase in the accuracy of measuring the intensity of inhomogeneous electric fields. The utility model relates to the field of measurement technology and can be used to measure the electric field strength in a wide spatial range with increased accuracy. 3 ill.

Description

The utility model relates to the field of measurement technology and can be used to measure the electric field strength in a wide spatial range with increased accuracy.

Known sensor for measuring the components of the electric field [Misakyan M., Kotter F.R., Kaler R.L. Miniature electric field sensor // Instruments for scientific research. – 1978. -№7.–S.52-55], containing a single-coordinate differential sensor with one pair of identical electrically conductive sensing elements in the form of hemispheres, diametrically located on the same coordinate axis, with the origin aligned with the center of the sensor housing, a differential converter of the output sensor signal, the first input of which is connected to the first sensitive element, and the second input - to the second sensitive element of the sensor, and its output is connected to the measuring device, while the sensor is oriented so that the electric field strength vector coincides with the direction of the coordinate axis of the sensor.

The advantage of the sensor is that it is double, since diametrically opposite pairs of electrically conductive sensitive elements are located along each coordinate axis of the sensor. And, the components of the electric field strength vector are judged by the magnitude of the charge difference between opposite pairs of sensitive elements. The use of a sensor in a differential connection leads to an increase in the accuracy of measurements, due to a decrease in common-mode components, i.e. external electrical interference.

The disadvantage of the sensor is that the sensor with measuring electrodes in the form of hemispheres, the angular size of which θ ₀ =90° in a non-uniform field has a negative error, the limit value of which reaches -35%. As a result, the value of the electric field strength will be underestimated.

It is also known a sensor implemented in a method for measuring the electric field strength [Patent RU No. 2388003, MKI G01 R 29/12, G01 R 29/08], containing an electrically conductive spherical housing with three pairs of electrically conductive sensitive elements, in pairs and symmetrically located relative to the surface of the sensor housing on its coordinate axes passing through the center of the spherical body, while the sensitive elements and the sensor body are isolated from each other.

The sensor of the second analogue is also made double and has the same advantages of a double sensor as the sensor of the first analogue.

The disadvantage of the second analogue is that its sensitive elements are made in the form of spherical segments with angular dimensions θ ₀ ≤45° and are part of a hemisphere having an angular dimension θ ₀ =90°. The limitation of the angular dimensions of spherical segments is caused by the exclusion of their overlapping. A sensor with sensitive elements in the form of spherical segments and angular dimensions θ ₀ ≤45° in an inhomogeneous field has a positive error, the limit value of which reaches +35%. As a result, the value of the electric field strength will be overestimated.

The closest is a sensor implemented in a device for measuring electric field strength with a dual sensor [Patent RU No. 207464 U1, MKI G01 R 29/12], containing a spherical sensor with two pairs of electrically conductive sensitive elements, the first pair of which is made in the form of spherical segments with angular dimensions θ ₀ ≤45°, and the second pair is made in the form of spherical segments with angular dimensions at the top θ ₀₁ ≥45° and at the base θ ₀₂ ≤90°. Both pairs of sensitive elements are located in pairs and symmetrically relative to the sensor surface on the same coordinate axes passing through the center of the electrically conductive spherical body, while the sensitive elements and the sensor body are isolated from each other, the first sensitive elements of the corresponding pair of elements are configured to be connected to the first inputs of differential transducers output signals of the sensor, and the second sensitive elements of the same pair are configured to be connected to the second inputs of the differential converters of the output signals of the sensor, the first input of the second adder is connected to the first input of the first adder and the output of the first differential converter, and the second input of the second adder is connected to the output of the first adder, the second input of which is connected to the output of the second differential converter, while the output of the second adder is connected to the measuring device.

In an inhomogeneous field, such a sensor has a positive error, the limiting value of which reaches +5%.

A common disadvantage of the known sensors is the low accuracy when measuring inhomogeneous electric fields in a wide spatial measurement range.

The objective of the utility model is to improve the accuracy of measuring the intensity of inhomogeneous electric fields in a wide spatial measurement range, i.e., to provide the possibility of measuring near field sources and conductive surfaces.

This task is achieved by the fact that in a known sensor for measuring the electric field strength, containing a spherical housing with two pairs of electrically conductive sensitive elements, the first pair of which is made in the form of a spherical segment with an angular size θ ₀ , and the second pair is made in the form of a spherical layer with an internal and external angular dimensions, respectively, selected from the conditions θ ₀₁ ≥θ ₀ and θ ₀₂ ≤90°, and the sensing elements are in pairs and symmetrically located relative to the sensor surface on the same coordinate axis passing through the center of the electrically conductive spherical housing, while the sensing elements and the sensor housing are isolated from each other, the first sensitive elements of the corresponding pair of elements are configured to be connected to the first inputs of the differential transducers of the output signals of the sensor, and the second sensitive elements of the same pair are configured to be connected to the second inputs of the differential transducers converters of the output signals of the sensor, and the outputs of the first and second differential converters of the output signals of the sensor, respectively, are connected to the first and second inputs of the first adder, the first input and output of which are connected, respectively, to the first and second inputs of the second adder, according to the claimed technical solution in the sensor, the first pair of sensitive elements in the form of a spherical segment is made with angular dimensions θ ₀ =47°, and the second pair of sensitive elements in the form of a spherical layer is made with angular dimensions at the top θ ₀₁ ≥47° and with angular dimensions at the base θ ₀₂ ≤90°, and the inputs of the second adder respectively are the outputs of the first and second dual sensors, and its output is the output of the dual sensor.

The proposed utility model is illustrated by drawings, where figure 1 shows a sensor, which is a dual dual single-coordinate sensor for measuring the electric field strength, which includes a measuring circuit; figure 2 shows the sensitive elements 2-3, made in the form of a spherical segment (fig.2, a), and the sensitive elements 4-5, made in the form of a spherical layer (fig. 2, b), and their angular dimensions, and figure 3 shows graphs of errors from the inhomogeneity of the electric field for the sensor, prototype δ ₃ , the proposed sensor: for the first δ ₁ , the second δ ₂ dual sensors in the dual sensor and dual sensor δ depending on the spatial measurement range a=R/d (R is the radius of the sensor housing 1, d is the distance from the center of the sensor housing 1 to the field source) for sensing elements 2-3, made in the form of a spherical segment with an angular size θ ₀ =47° and for composite sensing elements 2.4-3 ,5, forming a spherical segment (hemisphere) with an angular size θ ₀ =90°.

The dual electric field strength sensor consists of an electrically conductive spherical body 1 with two pairs of sensitive elements 2-3 located on its surface on the same coordinate axis, which are included in the first sensor and two pairs of composite sensitive elements consisting of elements 2.4 and 3.5, included in the second sensor, two two-input differential transducers 7 and 8 with low-resistance inputs and two two-input adders 9 and 10. Sensitive elements 2 and 5 are connected to the first inputs, and sensitive elements 3 and 4 are connected to the second inputs of differential transducers 7 and 8, respectively. The outputs of the first and second differential converters are respectively connected to the first and second inputs of the first adder, the output of which and the output of the first differential converter are respectively connected to the second and first inputs of the second adder. The outputs of the first differential converter 7 and the output of the first adder 9 are respectively the outputs of the first and second dual sensors, and the output of the second adder 10 is the output of the dual sensor. Differential converters 7 and 8, adders 9 and 10 represent the measuring circuit. The measuring circuit may be different, built, for example, using digital and microprocessor technologies. As differential converters of the measuring circuit, for example, differential current integrators or charge amplifiers can be used. The electrically conductive spherical body 1 can be the middle point of the sensor or a common bus 6 for the measuring circuit of the sensor.

The sensor works as follows.

и

(где k₁ и k₂ – коэффициенты преобразования первого и второго дифференциального преобразователя;

и

- разность зарядов с первой 2, 3 и второй 4, 5 пары чувствительных элементов соответственно). Напряжения U₁ и U₂ суммируются сумматором 9, на выходе которого формируется напряжение

(где k₃ – коэффициент суммирования сумматора 9;

- разность зарядов между парой составных чувствительных элементов, первый из которых состоит из элементов 2, 4, а второй из элементов 3, 5). Напряжения U₁ и U₃ пропорциональны разности зарядов с каждой пары чувствительных элементов 2-3 и составных чувствительных элементов 2,4-3,5, которые в свою очередь пропорциональны E₁ и E₂ напряженности измеряемого электрического поля E. Предварительно при градуировке датчика в однородном электрическом поле регулировкой коэффициентов преобразования k₃ при одной и той же напряженности E добиваются на выходах первого и второго датчиков выполнения равенства U₁=U₃. В этом случае будет выполняться условие E₁=E₂=Е. Напряжения U₁ и U₃ являются выходными напряжениями первого и второго двойных датчиков. Далее напряжения U₁ и U₃ суммируются сумматором 10, и суммарное напряжение U=U₁+U₃=k(E₁+E₂)=k_E (k -коэффициент суммирования сумматора 10) будет выходным напряжением датчика. При выполнении коэффициента суммирования

выходное напряжение U=k₀(E₁+E₂)/2=k₀E (где k₀=1) будет пропорционально среднему значению напряженности электрического поля

, между значениями E₁ и E₂, полученными первым и вторым двойными датчиками, входящими в состав сдвоенного датчика.The sensor is placed in the investigated electric field so that its coordinate axis is oriented in the direction of the electric field. Under the action of an electric field, electric charges are induced on the sensitive elements 2-3 of the first sensor and on the sensitive elements 4-5 of the second sensor included in the dual sensor. With the help of differential converters (current integrators) 7 and 8, the charge difference from each pair of sensitive elements of the first and second sensors is converted into voltages

and

(where k ₁ and k ₂ are the conversion coefficients of the first and second differential converter;

and

- charge difference from the first 2, 3 and second 4, 5 pairs of sensitive elements, respectively). The voltages U ₁ and U ₂ are summed up by the adder 9, at the output of which a voltage is formed

(where k ₃ is the summation factor of adder 9;

- charge difference between a pair of composite sensitive elements, the first of which consists of elements 2, 4, and the second of elements 3, 5). The voltages U ₁ and U ₃ are proportional to the difference in charges from each pair of sensing elements 2-3 and composite sensing elements 2.4-3.5, which in turn are proportional to E ₁ and E _{2 of} the strength of the measured electric field E. Before calibrating the sensor in uniform electric field by adjusting the conversion coefficients k ₃ at the same intensity E achieve at the outputs of the first and second sensors of the equality U ₁ =U ₃ . In this case, the condition E ₁ =E ₂ =E will be fulfilled. The voltages U ₁ and U ₃ are the output voltages of the first and second dual sensors. Next, the voltages U ₁ and U ₃ are summed by the adder 10, and the total voltage U=U ₁ +U ₃ =k(E ₁ +E ₂ )=k _E (k is the summation factor of the adder 10) will be the output voltage of the sensor. When performing the summation factor

output voltage U=k ₀ (E ₁ +E ₂ )/2=k ₀ E (where k ₀ =1) will be proportional to the average value of the electric field strength

, between the values of E ₁ and E ₂ obtained by the first and second dual sensors included in the dual sensor.

и

. The use of a dual sensor improves the accuracy of measuring inhomogeneous electric fields. The increase in accuracy is achieved by the fact that in an inhomogeneous field the measured values of the intensity E ₁ and E ₂ contain opposite in sign relative errors from the inhomogeneity of the field, respectively equal to

and

.

Taking into account the errors, we can write

и

,

and

,

where E is the intensity of the initial electric field.

The strength of the measured field is determined by the formula

,

,

- погрешность измерения, вызванная неоднородностью поля. В результате получаем значения напряженности электрического поля с погрешностью δ в два раза меньшей, чем разность модулей погрешностей первого δ₁ и второго δ₂ датчиков, входящих в состав сдвоенного датчика.where

- measurement error caused by field inhomogeneity. As a result, we obtain the values of the electric field strength with an error δ two times smaller than the difference in error modules of the first δ ₁ and second δ ₂ sensors included in the dual sensor.

Let's plot graphs (Fig. 3) of errors for the first sensor δ ₁ , the second sensor δ ₂ , the prototype δ ₃ and the claimed sensor δ depending on the relative distance a=R/d, (where R is the radius of the spherical sensor body, d is the distance from center of the sensor to the source of the field).

The plotting of error graphs δ ₁ , δ ₂ and δ is based on the well-known expression for calculating the error from the inhomogeneity of the field of sensors of a spherical shape [Biryukov S.V. Calculation and measurement of the electric field strength in electrical installations of over - and ultra-high voltage / S.V. Biryukov, F.G. Kaidanov, R.A. Katz, E.S. Kolechinsky, V.Ya. Lozhnikov, N.S. Smekalova, M.D. Stolyarov // The impact of high voltage electrical installations on the environment: Translations of the reports of the International Conference on Large Electrical Systems (SIGRE-86) (Energy abroad) / Ed. Yu.P. Shkarina. - M.: Energoatomizdat, 1988. - S. 6-13].

,

,

where a=R/d is the spatial measurement range, R is the radius of the spherical sensor body, d is the distance from the center of the spherical sensor body to the field source, θ ₀ is the angular size of the sensor's sensing element.

, получим график погрешности заявляемого датчика, которая в два раза меньшей, чем разность модулей погрешностей δ₁ и δ₂.Substituting in this formula the angular dimensions of the sensitive elements of the first θ ₀ =47° and the second θ ₀ =90° sensors, we obtain for them the graphs of errors δ ₁ and δ ₂ . Calculating the error

, we get a graph of the error of the proposed sensor, which is two times less than the difference between error modules δ ₁ and δ ₂ .

From the graphs of Fig.3 it follows that the dual sensor of the prototype with the angular dimensions of the sensing elements of the first sensor θ ₀₁ =45° and the second sensor θ ₀₁ =45° θ ₀₂ =90° allows you to reduce the measurement error of non-uniform electric fields to +4.6% at almost full spatial measurement range 0≤a<0.98 (d=1.02R).

The inventive double sensor makes it possible to halve the error of the prototype sensor in almost the same spatial measurement range. In this case, the first pair of sensitive elements in the form of a spherical segment must be made with angular dimensions θ ₀ =47°, and the second pair of sensitive elements in the form of a spherical layer must be made with angular dimensions at the top θ ₀₁ ≥47° and with angular dimensions at the base _θ02 ≤90°.

заявляемого двойного датчика при изменении углового размера θ0 чувствительных элементов первого датчика. В результате минимизации погрешности установлено, что при угловом размере θ₀=47° чувствительных элементов первого датчика погрешность сдвоенного датчика составляет δ=+2,1% и не превышает её в пространственном диапазоне 0≤a≤0,93 (d≈1,08R).The angular size of the sensitive elements θ ₀ =47° was obtained by finding the minimum error

of the inventive double sensor when changing the angular size θ0 of the sensitive elements of the first sensor. As a result of minimizing the error, it was found that with the angular size θ ₀ =47° of the sensitive elements of the first sensor, the error of the dual sensor is δ=+2.1% and does not exceed it in the spatial range 0≤a≤0.93 (d≈1.08R ).

Thus, a dual sensor with sensing elements in the form of a spherical segment with optimal angular dimensions θ ₀ =47° of the sensing elements of the first sensor and with sensing elements in the form of a spherical layer with angular dimensions, at the top θ ₀₁ ≥47° and at the base θ ₀₂ ≤ 90° of the second sensor allows to achieve a significant increase in the accuracy of measuring the intensity of inhomogeneous electric fields.

Claims (1)

A dual sensor for measuring the electric field strength with composite sensitive elements, containing a spherical housing with two pairs of electrically conductive sensitive elements, the first pair of which is made in the form of a spherical segment with an angular size θ₀, and the second pair is made in the form of a spherical layer with internal and external angular dimensions, respectively, selected from the conditions θ₀₁≥θ₀ and θ₀₂≤90°, and the sensing elements are arranged in pairs and symmetrically relative to the sensor surface on the same coordinate axis passing through the center of the electrically conductive spherical body, while the sensing elements and the sensor body are isolated from each other, the first sensing elements of the corresponding pair of elements are configured to be connected to the first inputs of differential output signal converters sensor, and the second sensitive elements of the same pair are configured to be connected to the second inputs of the differential converters of the sensor output signals, and the outputs of the first and second differential converters of the sensor output signals, respectively, are connected to the first and second inputs of the first adder, the first input and output of which are connected, respectively, to the first and second inputs of the second adder, characterized in that in the sensor the first pair of sensitive elements in the form of a spherical segment is made with angular dimensions θ₀=47°, and the second pair of sensitive elements in the form of a spherical layer is made with angular dimensions at the top θ₀₁≥47° and with angular dimensions at the base θ₀₂≤90°, and the inputs of the second adder are respectively the outputs of the first and second dual sensors, and its output is the output of the dual sensor.

Images