234 results about "Soil resistivity" patented technology

The invention discloses a method for evaluating soil corrosivity of a grounding grid of a substation in Guangdong region, and relates to a method for evaluating the soil corrosivity. The method comprises the following steps: (1) picking up the soil on the buried depth position of the grounding grid to measure eight soil parameters(1) by conventional methods; (2) utilizing an eight index comprehensive grading method to determine a comprehensive grade(2); and (3) determining the grade of the soil corrosivity according to an eight index comprehensive grading result(3). The eight soil parameters include soil texture(1.1), soil pH value(1.2), soil electric resistivity(1.3), soil salt content(1.4), soil water content(1.5), corrosion potential(1.6), and soil C1+2SO4 content (1.7). The method is not only used for evaluating the soil corrosivity environment caused by the grounding grid steel of the substation operated in Guangdong region and predicting the soil corrosivity environment caused by the grounding grid steel of a newly built substation, but also applied to evaluating the corrosive protection of the buried steel in other industries in Guangdong region.

The invention relates to a simulation test method for testing the lightning protection performance of a pole and tower grounding device of high-voltage power transmission line. The existing impulse grounding test process has the problem that a test model is simple and small in comparison with a real grounding device, or the problem that the simulation experiment has large gap from the real condition resulting from the large difference between a test power supply and the real lightning current. The simulation test method provided by the invention comprises the following steps: measuring soil resistivity of the test field; determining the position of a voltage reference point during the impulse grounding test according to the power frequency ground resistance measurement result of the grounding device; arranging voltage and current leads during the impulse grounding test; carrying out large-current impulse grounding measurement of the grounding device; measuring the power frequency ground resistance of the grounding device again in such a manner that all electrodes are located in the same positions as in the previous measurement; and analyzing the impulse test result. The simulation test method provided by the invention can narrow the gap between the simulation test and the real condition, and can be used for resistance reduction scheme optimization and impulse performance evaluation of the pole and tower grounding device of the high-voltage power transmission line.

The invention discloses a grounding simulation testing device and a grounding simulation testing method. The grounding simulation testing device consists of a transparent container, a transparent liquid medium and an equivalently-contracted grounding device model. The method comprises the following steps of: simulating the variation of earth resistivity by adjusting the resistivity of the liquid medium in the transparent container; simulating non-uniform distribution of soil resistivity by arranging a horizontal or vertical insulated spacer layer in the transparent container; simulating grounding devices of different types by changing the shape of the grounding device model; simulating different grounding device types or the dispersion processes and dispersion mechanisms of different soil structures flowing through working frequency, direct-current and lightning impulse current by arranging working frequency, direct-current and impact testing power supplies; embedding a sampling sensor; measuring needed testing parameters; and recording a testing process through a video camera. The grounding simulation testing device and the method have the advantages of simple and compact structure, easiness in operating and high equivalence.

The invention belongs to the technical field of lightning-proof grounding of transformer station engineering, and particularly relates to a resistance reduction analysis and measurement system applied to a transformer station lightning-proof grounding system. The invention provides a resistance reduction analysis and measurement system applied to a transformer station lightning-proof grounding system, and the system can effectively solve the technical problem of grounding. The system includes a resistance reduction database, a resistance reduction problem application part and a ground resistance on-line monitoring part; the resistance reduction problem application part collects field soil environment data, extracts the resistance reduction database, determines a structure of the structure of layering arrangement and soil texture environmental data which are related with the ground resistance, and calculates the geological environment of the grounding system; a solution is selected in the database, calculation of the grounding system is completed, and the mode and the structure of grounding of a transformer station are determined; and the calculation flow of the grounding system is as follow: soil resistivity and grounding area data are collected, and thermostabilization examination of a grounding device is performed.

The invention provides a transient electromagnetic exploration method and apparatus for tundra natural gas hydrates. The method comprises the following steps: exploration data of an exploration zone is obtained; apparent resistivity characteristics of formation lithology at different depths are analyzed according to frozen soil data, soil resistivity data and rock resistivity data; and a distribution mode of the apparent resistivity is determined; according to the geological data and exploratory well data, geological structure characteristics of the geological exploration area are determined, and measuring lines and measuring points of transient electromagnetic data acquisition are determined; transient electromagnetic data of the exploration area is acquired; apparent resistivity at different depths is respectively calculated according to the transient electromagnetic data in a full-time channel mode and a time-channel segmented mode, and a corresponding apparent resistivity sectional drawing is generated; the actual apparent resistivity sectional drawing is determined according to the distribution mode; and according to the apparent resistivity characteristics, the geological structure characteristics and the real resistivity sectional drawing, the distribution condition of a natural gas hydrate occurrence layer is determined.

The invention relates to a buried steel pipeline coating stripping and corrosion test system under a stress and stray current coupling effect, and belongs to the field of pipeline corrosion and coating stripping detection. The test system comprises a stress loading test system, a soil environment simulation system, a stray current simulation system, a cathode protection system, and an electrochemistry test system. With the test system, actual working conditions of a buried steel pipeline can be simulated, corrosion law experiments under different influence factors (soil resistivity/conductivity, soil pH value, different stress levels, stray current types/intensity, damage area/stripping area, and the like) can be performed on pipelines, a pipeline cathode stripping experiment and an experiment of stripping produced on a coating damage position due to stray current inflow can be performed, and an experiment of underlayer corrosion caused by pipeline cathode stripping and an experiment of corrosion (including stray current corrosion) caused by coating damage can be performed. The method can be suitable for buried steel pipeline coating stripping and corrosion detection laboratory researches and preliminary studies of pipeline production enterprises.

The invention discloses a method for forecasting DC biasing current influence of multiple DC grounding electrodes on sites in different operation modes. According to the method, a DC online monitoring device is mounted at the neutral point of a transformer near the DC grounding electrodes to grab the actual measurement data of distribution of the DC biasing current; next, the resistivity and the thickness of each layer of soil are adjusted to correct a simulation model according to the actual measurement data, and then the corrected soil model is used for forecasting the influence conditions of the DC biasing of the power grid in the area having multiple DC grounding electrodes under different operating conditions; for the transformer having the DC current exceeding a set value, protection measures can be applied to the transformer in advance, and therefore, the purpose of targeted DC biasing current protection can be achieved. The method has the beneficial effects that the early warning capability on the DC biasing of the power grid transformers is improved and the effective protection measures can be adopted for the transformers having great DC biasing risk conveniently and immediately.

The invention belongs to a preparation method of a high-water-retaining property bentonite resistance reducing agent. In order to solve the problems that resistance reduction is difficult and a resistance reducing effect cannot last in a high-soil resistivity region, the method comprises the following steps of: preparing activated calcium-base bentonite serving as a main material of the resistance reducing agent by employing a bentonite activation modification technology; preparing the high water-retaining property bentonite resistance reducing agent by using materials such as sodium polyacrylate water absorbent resin, a compound multi-metal general gas-phase corrosion inhibitor, sodium chloride and clay; and carrying out special combined packaging on the resistance reducing agent. The high-water-retaining property bentonite resistance reducing agent prepared by the method can be applied to a lightning protection and electric grounding system and laid around a grounding body, and the grounding resistance of the grounding body is reduced by increasing the equivalent area of the grounding body, reducing contact resistance between the grounding body and surrounding soil and improving and keeping the conductive property of the surrounding soil of the grounding body for a long time.

A testing device which may be used to conduct ground resistance and soil resistivity measurements. The testing device comprises both a main unit and a remote unit adapted to communicate with one another via a communication link. After setting the testing device up according to the desired measurement technique, the procedure may be carried out, and the resulting measurement values are subsequently displayed on the remote unit. This allows a single operator to perform measurements while standing directly adjacent to an electrode, which is, for example, placed at a large distance from the main unit and/or other electrodes. This relieves the operator from constantly having to walk back and forth placing electrodes in different positions, and also obviates the need to return to the main unit of the testing device to consult a display and/or change parameters or settings.

The invention discloses an anti-interference soil resistivity measurement method based on phase identification. The method comprises the first step of selecting soil to be measured and driving current electrodes and voltage electrodes into the earth surface in sequence along the straight line according to a preset electrode distance, the second step of selecting a power source according to a preset frequency, and injecting current signals into the earth surface of the soil to be measured through the current electrodes, the third step of measuring and getting voltage signals on the voltage electrodes, the fourth step of obtaining cophase components of the voltage signals and the current signals at the preset frequency through phase identification, and the last step of calculating the soil resistivity through a soil apparent resistivity formula. According to the method, 125-Hx measuring frequency different from 50-Hz power frequency is adopted, so good anti-interference capacity can be achieved even on triple-frequency harmonic, interference of lead mutual-inductance on an on-site soil resistivity electrical test result is effectively eliminated, and the measurement accuracy is improved. The method can be widely applied to resistivity measurement of the soil along power transmission lines or the soil in a substation and other places, is particularly suitable for measurement at a large electrode distance and can well eliminate influences of lead mutual-inductance of the voltage electrodes and the current electrodes.

The invention relates to a buried steel pipeline coating stripping and corrosion test method under a stress and stray current coupling effect, and belongs to the field of pipeline corrosion and coating stripping detection. Systems used by the method comprise a stress loading test system, a soil environment simulation system, a stray current simulation system, a cathode protection system, and an electrochemistry test system. With the test systems, actual working conditions of a buried steel pipeline can be simulated, corrosion law experiments under different influence factors (soil resistivity/conductivity, soil pH value, different stress levels, stray current types/intensity, damage area/stripping area, and the like) can be performed on pipelines, a pipeline cathode stripping experiment and an experiment of stripping produced on a coating damage position due to stray current inflow can be performed, and an experiment of underlayer corrosion caused by pipeline cathode stripping and an experiment of corrosion caused by coating damage can be performed. The method can be suitable for buried steel pipeline coating stripping and corrosion detection laboratory researches and preliminary studies of pipeline production enterprises.

The invention discloses a method for assessing soil corrosivity. The method comprises the following steps: 1) determining measuring indexes of the soil; (2) fragmenting the numbers of each measuring index, and determining the value corresponding to the number in each fragment; (3) sampling the soil, and detecting the measuring indexes determined in step 1); 4) determining the value of the number detected in step 3) according to step 2); and 5) summing the values determined in step 4) and corresponding to each measuring index, and finally assessing the corrosivity of the soil based on the calculating result. By applying the technical scheme of the invention, the technical problems that the large deviation is generated during measuring the resistivity and oxidation-reduction potential of the dry soil with high gravel content and relatively deep water level of groundwater due to the resistance of the gravel to the moving of electrons can be avoided; and compared with a multi-index comprehensive assessment method, the method disclosed by the invention is simpler and more convenient and practical.

The invention discloses a method for acquiring a resistance of a power station or transformer substation grounding grid with karst geological and geomorphic characteristics. The method comprises the following steps of: step I, determining a grounding soil resistivity and a test point; step II, calculating a resistance of a main grounding grid; step III, calculating a resistance of an auxiliary grounding grid for reducing a soil resistivity; and step IV, calculating the resistance of the power station or transformer substation grounding grid with the karst geological and geomorphic characteristics. According to the method for acquiring the resistance of the power station or transformer substation grounding grid with the karst geological and geomorphic characteristics, two technical problems of non-uniform soil resistivity and ultrahigh soil resistivity of the grounding grid with the karst geological and geomorphic characteristics are solved.

The invention discloses a method for measuring porosity of soil, which comprises the following steps: (1) selecting different sampling points on a soil surface; (2) building a model of soil porosity and electrical resistivity; (3) measuring different saturability and porosity of current soil for carrying out electrical resistivity tests, and calibrating parameters of the model of soil porosity andelectrical resistivity; (4) measuring the soil electrical resistivity, and obtaining the porosity of current soil through the model of soil porosity and electrical resistivity. Compared with samplingtesting, the method ensures that soil is not destroyed to the utmost extent, and ensures the accuracy of porosity measurement. The method can avoid destroying the soil original structure in a sampling measuring process, thereby retaining the original density, the water content and other elements of soil to the utmost extent, and fundamentally reducing measurement errors; moreover, the method is simple to operate and short in measurement period, thereby meeting detection requirements on changed soil porosity in engineering.

The invention relates to soil corrosion field, specifically to a device for studying soil corrosion, aiming to solve the problems of the prior art, including less function, high dependence of external environment and high error generation liability. The device comprises two test tanks connected with each other through a latex tube provided with a ion conduction passage formed by saturated KCI gel containing 2-3% agar; and the test tank is composed of a PVC tube and a PVC plate disposed at the bottom of the PVC tube and filled with soil medium, and an auxiliary electrode with respect to the working face and a study electrode are disposed in upper part and lower part of the soil medium. The invention uses two independent test tanks communicated by the ion conduction passage in the latex tube, and can simulate different consolidation degree of soil. The soil may not be contacted with each other, so as to prevent diffusive penetration of water and salt. The inventive device has the advantages of reliable measurement results and low error; and can be used for studying soil corrosion, measuring soil resistivity and calculating the volume density and air rate of the test soil.

The invention discloses a substation grounding grid corrosion monitoring system which includes a corrosion monitoring sensor and a corrosion monitoring device, wherein the corrosion monitoring sensor includes an auxiliary electrode, a guard ring electrode, a solid reference electrode, a stainless steel cylinder and a stainless steel casing; the corrosion monitoring device includes an MCU controller, a sine wave generator, a data acquisition unit, a power supply module, a clock circuit, and an AC impedance circuit connected with the auxiliary electrode, the guard ring electrode and the solid reference electrode of the corrosion monitoring sensor; the AC impedance circuit includes a power amplifier connected to the auxiliary electrode, a current constraint circuit connected to the guard ring electrode, and a main polarization circuit connected to the solid reference electrode. The invention provides a grounding grid online corrosion monitoring system which integrates the small-hole current limiting, guard ring electrode current constraint and AC impedance technology and is used for the long-term monitoring of grounding grid corrosion rate and soil resistivity.

The invention relates to an electrical impedance tomography imaging plant root system architecture in-situ observation method which comprises the steps of 1, evenly distributing N electrodes in the soil containing a plant root system in a circular shape, sequentially applying sinusoidal alternating current (AC) on two of the electrodes, and measuring the voltage between every two adjacent electrodes in the rest electrodes to obtain voltage data; 2, carrying out finite element mesh partition on the cross section of circumference provided with the electrodes in the soil; 3, carrying out system matrix calculation on the voltage data obtained in the step 1 to obtain the resistivities of all the grids obtained in the step 2, wherein each resistivity represents the resistivity of the corresponding position in the solving domain; imaging by utilizing the resistivity data, setting different colors for units with different resistivities according to the resistivity values of the units by a red, green and blue (RGB) color mode, and judging the different resistivities of all the units according to the colors of the image; according to the difference between the root system and the surrounding soil resistivity, determining the shape and the position of the root system to realize the plant root system architecture in-situ observation.

The invention discloses a method for extracting metro stray current corrosion characteristic information based on a data mining technology. The method comprises: 1, key data acquisition at the subwaysite: measuring surrounding soil resistivity, rail transit resistance and steel rail longitudinal resistance and analyzing soil ion composition, 2, equivalent treatment on metro field key data, 3, laboratory environmental electrochemical corrosion simulation, 4, experimental data mining and corrosion feature information extraction, and 5, assessment of stray current corrosion risk according to corrosion feature information. The method can acquire the necessary data of the subway field according to the data mining technology, extract stray current electrochemical corrosion feature information,evaluate the stray current corrosion risk according to the corrosion characteristic information and predict the corrosion degree and service life of the buried metal in the future.

The invention provides a lightning trip-out rate test method considering line soil resistivity differentiation. The method is characterized in that a test platform is built, and the test platform comprises an impulse voltage generator, a data measurement analysis control module, a wireless current sensor, a coaxial cable I, a coaxial cable II, a coaxial cable III, a first base tower, a second basetower, a third base tower, a lightning conductor, an A-phase line, a B-phase line and a C-phase line. The test method comprises the steps that the coaxial cable I is connected with the impulse voltage generator and a bidirectional contact; the other end of the bidirectional contact is connected with the C-phase line and the tops of the towers; a generator connecting line is surrounded by the wireless current sensor; measurement data are fed back to the data measurement analysis control module through the wireless current sensor; and the lightning trip-out rate is obtained through calculation.According to the invention, the lightning trip-out rate of a power transmission line under different soil resistivity conditions can be effectively calculated, so that lightning safety evaluation ofthe power transmission line and the tower structure can be realized.

The invention discloses a new method for determining the grounding resistance value of a large-scale grounding system. The new method is characterized in that an apparent resistance calculating curve and an apparent ground resistance measurement curve are simulated through a computer and compared to be coincident, and the grounding resistance value when the large-scale grounding system independently exists can be accordingly and finally determined based on the earth resistivity and the grounding resistance value which are measured on site. The new method has the advantages that utilization of the method is not influenced by the local soil structure on site, and when measurement is not required to be carried out, the distance between the position of a current electrode and the grounding system must be more than 6.5 times the size of a grounding grid. In this way, based on physical conditions such as the site complex terrain structure and multiple in-and-out-line loops of power generating stations and transformer substations, nondestructive measurement on the grounding resistance of the large-scale grounding system can be carried out, and the measurement and calculation accuracy is improved.

The invention discloses a multifunctional garbage soil degradation compression apparatus. The apparatus includes an axial compression system, a confining pressure simulation system, a penetrating fluid circulation system, a gas analysis system, an automatic data acquisition system and other auxiliary fitting systems. The apparatus provided pressurizes the test by means of an axial compression device, provides the confining pressure and constant temperature conditions through the gas by means of a temperature controlled pressure confining device, and performs the penetrating fluid uniformly distributed recirculation and degraded gas recovery to test the resistivity of the soil sample. The compressor has the following advantages of 1) solving the limitation that a degrading instrument cannot provide the confining pressure; 2) providing the controllable vertical pressurization setting; 3) performing the dynamic monitoring of penetrating fluid flow velocity, flow and compositions; 4) providing a resistivity testing module and testing the garbage soil resistivity changes in different degrading and deposition stages; and 5) monitoring the degraded gas compositions and flow, and achieving the novel and multifunctional aims.

The invention relates to a device and method for diagnosing the corrosion state of a grounding electrode based on relative grounding resistance, and belongs to the technical field of operation and management of power transmission and transformation equipment. The method comprises the following steps of S1, designing the grounding electrode and calculating the relative grounding resistance of the grounding electrode; S2, selecting a method for diagnosing the corrosion state of the grounding electrode according to different soil resistivities; S3, selecting a corrosion diagnosing criterion basedon the relative grounding resistance according to the soil resistivities; S4, designing and measuring the grounding resistance of the grounding electrode; S5, designing and measuring the soil resistivity of soil where the grounding electrode is located. The design method eliminates the influence of the soil resistivities on a diagnosis result of the corrosion state of the grounding electrode, achieves the classification of the corrosion state of the grounding electrode and further improves the accuracy of the diagnosis result of the corrosion state of the grounding electrode.

The present invention provides a graphite aluminum-magnesium alloy grounding material which is obtained through the following steps: placing the graphite into a mixed solution of hydrochloric acid and nitric acid for immersing and acid washing twice for changing the inner structure, after rinsing until the pH value gets to 7.0, dewatering for high-temperature swelling, expanding the graphite worm to 50-70 times of normal volume; adding magnesium powder, aluminum powder, manganese powder and zinc powder, mixing to uniform; executing extrusion forming to the graphite worm under the pressure of 5-8MPa for forming a graphite worm bland; and executing high temperature sintering. According to the invention, the graphite is added with metallic ions of magnesium, aluminum, manganese and zinc. The graphite aluminum-magnesium alloy grounding material of the invention has the advantages of stable resistance value of product, good corrosion resistance, cathodic protection provided for the main grounding system, effectively reduced grounding resistance and delayed corrosion efficiency of main grounding network. The graphite aluminum-magnesium alloy grounding material of the invention is suitable for the grounding of high soil resistivity areas (mountain area, sand land, etc.) including the tower of transmission line, meteorological station and ecological monitoring station.