SU1113764A1 - Method and device for measuring parameters of electric field in conductive medium - Google Patents

Abstract

1. A method of measuring the parameters of an electric field in a conducting medium in which an electrical transducer is placed in the test medium, with which the electric field passing through the test medium is concentrated and converted into an electric current, characterized in that, in order to increase the sensitivity , increase the accuracy of measurements and the extension of the range of measured signals, periodically compensate the voltage in the measuring circuit of the electric converter and measure it in the absence of compensation the voltage in the measuring circuit and the compensating voltage, which determine the parameters of the electric field;

Description

2. A device for carrying out the method according to Claim 1, comprising electric current thickeners separated by a dielectric pad and connected by an electrically conductive rod on which a measuring coil is located connected to the preamplifier input, characterized in that it contains 3764

A compensating coil, a controlled voltage source, a key element, the compensating coil is located on an electrically conductive rod and connected to the output of a controlled voltage source, the control input of which is connected through a key element to the output of the preamplifier.

The invention relates to technical physics and electrical measuring te | nikv, namely to measurements of electric fields in conducting media. The invention can be used to create onboard and stationary measuring systems designed for geophysical investigation of electric fields in the marine environment and the ground. There is a known method for measuring the parameters of an electric field in a conductive medium, in which an electric converter is placed in the test medium and the electric field is focused through a converter using field thickeners connected to an electric converter P. It is also known a device for realizing this method containing an electrically conductive rod connected to a thickener by a spinner, made in the form of halves of a conducting hollow spheroid, on which measuring current transformer C1 is fixed. However, this method and device is characterized by insufficient sensitivity and low conversion coefficient in the low frequency region, which is associated with high resistance of the polarized double layer formed on the surface of the thickeners. In addition, the accuracy of this method strongly depends on the electrophysical parameters of the conductive medium and the material from which thickeners are made, and the current transformer cannot be used in principle for direct measurement of constant and infra-low-frequency electric fields. The closest to the technical essence of the invention is a method of measuring the parameters of an electric field in a conducting medium, according to which an electrical transducer is placed in the medium under study, with it the electric field passing through the medium under study is concentrated and converted into electric current C21. It is also known a device for implementing this method, which is an electric current thickener, separated by a dielectric gasket and connected by an electrically conductive rod on which a measuring coil is connected to the input of the preamplifier L21. A gasket connects electrical current thickeners through a switch that acts as a modulator. The device conducts the measured 1 under constant boundary conditions on the contact surface of the sensor thickener with the surrounding conductive medium, which is achieved by using an electrically conductive rod and a spinner of the thickener divided into two parts, respectively, by two insulating spacers, parallel to each of which the modulator switching circuits are connected . The disadvantage of this method and device is a decrease in the limiting sensitivity due to the fact that the well-known key switching elements have a high level of internal noise, which is significantly superior to the intrinsic noise of the primary measuring circuit of a current transformer with thickeners. In addition, the intensity of the intrinsic noise of the limestone: key elements is inversely proportional to their maximum switching frequency, which limits the frequency range of the measured signals in medium and high frequency regions. The purpose of the invention is to increase the sensitivity, increase the accuracy of measurements and expand the frequency range of the measured signals. This goal is achieved by the fact that according to the method of measuring the parameters of an electric field in a conducting medium, c. in which an electrical converter is placed in the test medium, with which the electric field passing through the test medium is concentrated and converted into an electrical current, the voltage in the measuring circuit of the electrical converter is additionally compensated and measured in the absence of compensation and the compensating voltage, which determine the parameters of the electric field. I The goal is achieved by the fact that the device that implements the method and contains electric current thickeners, separated by an electric gasket, connected by an electrically conductive rod, on which is located the measuring coil connected to the preamplifier input, contains a compensating coil, controlled source voltage, the key element, and the compensating coil is located on the electrically conductive rod and connected to the output of the controlled voltage source, the control input of which through a key element connected to the output of the preamplifier. The method of measuring the parameters of an electric field in a conductive medium is based on periodically compensating for voltage applied to the primary current transformer circuit with thickeners, and measuring the time-shifted voltage of the secondary current transformer circuit with thickeners in the absence of compensation and compensating voltage, the magnitude of which determines the parameters of the electric field in a conducting medium. FIG. 1 shows a block diagram of a device implementing the method; in fig. 2 - an example of the implementation of the device; in fig. 3-5 are diagrams illustrating the operation of the device. The proposed method is based on the periodic voltage compensation applied to the primary circuit of a current transformer with thickeners, containing (Fig. 1 and 2) current thickeners separated by a dielectric gasket by a partition 2 and connected by an electrically conductive rod 3, on which the measuring coil 4 is connected, to the input of the preamplifier 5, and a compensating coil 6 connected to the output of the controlled source. Voltage 7, and the output of the pre-Io amplifier 5 is connected to the control input of the control of the voltage source 7 through the key element 8. As is known, the intensity of the measured electric field, taking into account the parameters of the conducting medium and the double polarization layer formed on the surface of the thickeners, can be represented as a replacement circuit of the active two-pole device, in which the voltage is idle move U ;; proportional to the intensity of the measured electric field, and the proportionality coefficient depends only on the geometry of the thickeners, and the output resistance Zg characterizes the parameters of the conducting medium and the double polarization layer. AT . Therefore, in the equivalent replacement circuit, the described active two-port network is connected to the primary current transformer circuit with thickeners, which is a so-called volumetric coil, which is closed through the thickener 1, the electrically conducting rod 3 and the surrounding conductive one. Wednesday The secondary winding of the current transformer with thickeners is the measuring coil 4. The required measurement mode is achieved by periodically closing the key element 8, which connects the control input of the controlled voltage source 7 to the output of the preamplifier 5 and thereby taking into account the output controlled voltage source 7 is connected to the compensating coil 6, closes the feedback circuit, 4fo in turn provides periodic compensation for the voltage applied to the primary circuit current transformer with thickeners. The measured time-shifted voltage of the secondary circuit of the current transformer with thickeners, amplified by the preamplifier 5, i.e. the voltage Vj and the compensating voltage and, as well as the transfer coefficients of the devices included in the replacement circuit, it is possible to determine the strength of the measured electric field and the parameters of the conductive medium. The method is implemented using a device containing thickening current 1, separated by a dielectric partition 2 and connected by an electrically conductive rod 3, on which measuring coil 4 located at the input of preamplifier 5 is located, and a compensating coil 6 connected to the output of a controlled voltage source 7, the control input of which is connected via the key element 8 to the output of the preamplifier 5. The input of the first integrating analog-digital converter 9 (FIG. 2) is connected to the output of the pre-amplifier dual amplifier 5. The input of the second integrated analog-to-digital converter 10 is connected to the output of a controlled voltage source 7. The inputs of the first 11 and second 12 buffer registers are connected to the output of the first integrated analog-digital converter 9. The output of the second integrating analog-digital converter 10 is connected to the input of the third buffer register 13. The outputs of the buffer registers 11-13 are connected to the input bus of the microprocessor sections 14 block. The microprocessor control block 15 is connected to the microprocessor sections 14 block and the persistent memory 16, which turn connected to a block of microprocessor sections 14, a key element 8, integrating analog-digital converters 9 and 10, and buffer registers 11-13. The oscillator 17 of the clock 1 Ls is connected to the block 15 of the microram control and the block 14 of the oprocessor sections. The manual is implemented as follows. In the absence of compensation, the pre-ITE voltage is 5 p-kc, p-k, and the no-load voltage in the active two-pole replacement circuit; Zg is the output impedance in the active bipolar circuit; ZY - current transformer input resistance with thickeners 2; Z, is the output impedance of the controlled source of compensating voltage 7, given in the primary measuring circuit; n is the transformation ratio of the current transformer with thickeners 2; KI is the preamplifier gain 5; gy is the input gain. compensation period output voltage preamplifier5 Unv (U, -U) -Kg.n.K UK - compensating voltage. If the compensating voltage is applied to the voltage U through the transfer factor K, i.e. l of compensating voltage, taking into account (2) p.Kb, gKx KK 1 + n-Kg, -K, the system of equations Ut-UK-K K-Un, - Uv Taking into account / L-U .; ZT where Е is the intensity of the measured electric field; L is a proportionality coefficient, called the equivalent base, the following relations can be obtained: Un Ut К L (K-Ua, -UK) ZTUt; .n-Kv · K. Thus, according to measurements of Unvj and Uvc. It is possible to determine the intensity of the measured electric field EJ and the output resistance Zg, depending on the parameters of the conducting medium and the double polarization layer. A device that implements the method. operates as follows. I At time t, the key element 8 is opened, which leads to the opening of the feedback circuit, and the associated transients begin in the circuit, which ends at time t, | (Fig. 3-5). At the output of the preamplifier 5, a voltage is established which for t is integrated in the first time analog-to-digital converter 9. At time t, the key element 8 closes and the transients begin to occur in the circuit, which time tj. In the time period tj - tj, the first integrating analog-to-digital converter 9 measures the voltage CT) integrated into the period of time tij - tj, so that by the time tj the digital outputs of the first integrated analog-digital converter 9 establish the code corresponding to the measured at the time U (, j ,, which is then recorded at time tt -tj in the K-Un, UK (4) time tj at the output of the controlled U. n-CCK, described dependencies 11137648 buffer register 11. By the time the source voltage 7 is set U, which then integrates the time flow into t with the second integrated analog-to-digital converter 10. At time t, key element 8 opens, which causes the feedback loop to open, and the associated transients begin in the circuit, which are finished by the time tg. Pa output preamplifier 5 sets the voltage C, which for the time tg - t is integrated in the first integrating analog-to-digital converter 9. To the time t: j on the digital outputs of the first integra uyuschego analog-to-digital converter 9 code set corresponding to the measured voltage Un42 which then via time-tr fcftg -t; is written to the second buffer register 12. At time tj, the digital outputs of the second integrated analog-to-digital converter 10 are set to a code corresponding to the measured AC voltage, which is then written to the third buffer register through the time t tg -tg. In the time period (t) - tg in the block of microprocessor sections 14, the parameters of the electric FIELD are calculated taking into account formulas (5) and (6) and the following relationship: - Uns × Thus, at time tq on the output bus of the block of microprocessor sections 14 A code appears corresponding to the parameters being measured. Further, the measurement cycle is repeated in the same way, and by the time t / ij, the next sample appears at the output. The operation of the device is synchronized using a clock pulse generator 17. The microprocessor control unit 15, together with the permanent storage device 16, controls the operation of the block of microprocessor sections 14, the key element 8, the integrated analog-digital converters 9 and 10, the buffer registers 11-13.

From the output bus of the block of microprocessor sections 14, the values of the parameters of the measured electric field, represented numerically in the form of samples, can be transmitted over the channel to other devices.

Due to the periodic compensation of the voltage of the primary circuit of the current transformer with thickeners, a high frequency alternating current flows through the double polarization layer corresponding to the compensation frequency, which leads to a sharp decrease in the impedance of the double polarization layer, which has a frequency-dependent and monotonic character that decreases with increasing frequency. Since the extreme sensitivity of measurements is due to thermal noise of the input measuring circuit, which in turn

depends on the active resistance of the double polarization layer, the proposed method allows to increase the sensitivity of the measuring transducers by 3-10 or more times.

In addition, as shown by the extrusion (5), when measuring the intensity of the investigated electric field, the dependence of the results on the electrophysical parameters of the environment is excluded, which increases the accuracy of measurements by 33% when the environmental conductivity doubles.

Transferring the switching elements from the primary current transformer circuit with thickeners to the secondary circuit eliminates the disadvantages of the prototype associated with the noise of the switching elements and extends the frequency range of the measured signals to the medium and high frequencies.

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Claims (2)

1. A method of measuring the parameters of an electric field in a conductive medium in which an electric transducer is placed in a test medium, by which the electric field passing through the test medium is concentrated and converted into an electric current, characterized in that, in order to increase the sensitivity, increasing the accuracy of measurements and expanding the range of measured signals, periodically compensate for the voltage in the measuring circuit of the electrical converter and measure in the absence of compensation voltage of a measuring circuit and a compensating voltage, which determine the parameters of the electric field; SU. „. 1113764 Fig 1 1 1 13764 2. The device for implementing the method according to claim 1, containing electric current thickeners, separated by a dielectric gasket and connected by an electrically conductive rod, on which a measuring coil is located, connected to the input of the pre-amplifier, characterized in that it contains a compensating coil, a controlled voltage source, a key element, and the compensating coil is located on the electrically conductive rod and connected to the output of the controlled voltage source, the control input of which is through h the key element is connected to the output of the preamplifier.