CN102707191A - Diagnosis device and diagnosis method for corrosion of earth screen of large-size transformer substation - Google Patents
Diagnosis device and diagnosis method for corrosion of earth screen of large-size transformer substation Download PDFInfo
- Publication number
- CN102707191A CN102707191A CN2012101215849A CN201210121584A CN102707191A CN 102707191 A CN102707191 A CN 102707191A CN 2012101215849 A CN2012101215849 A CN 2012101215849A CN 201210121584 A CN201210121584 A CN 201210121584A CN 102707191 A CN102707191 A CN 102707191A
- Authority
- CN
- China
- Prior art keywords
- lead
- measuring
- measurement
- corrosion
- box body
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 238000005260 corrosion Methods 0.000 title claims abstract description 36
- 230000007797 corrosion Effects 0.000 title claims abstract description 34
- 238000000034 method Methods 0.000 title claims abstract description 29
- 238000003745 diagnosis Methods 0.000 title claims abstract description 28
- 238000004891 communication Methods 0.000 claims abstract description 21
- 238000005259 measurement Methods 0.000 claims description 57
- 239000004020 conductor Substances 0.000 claims description 13
- 230000005540 biological transmission Effects 0.000 claims description 11
- 230000001681 protective effect Effects 0.000 claims description 11
- 230000005284 excitation Effects 0.000 claims description 7
- 238000003466 welding Methods 0.000 claims description 7
- 239000000463 material Substances 0.000 claims description 6
- 238000006243 chemical reaction Methods 0.000 claims description 5
- 230000008569 process Effects 0.000 claims description 5
- 239000003973 paint Substances 0.000 claims description 4
- 238000012360 testing method Methods 0.000 claims description 4
- 229920000122 acrylonitrile butadiene styrene Polymers 0.000 claims description 3
- 238000009933 burial Methods 0.000 claims description 3
- HPDFFVBPXCTEDN-UHFFFAOYSA-N copper manganese Chemical compound [Mn].[Cu] HPDFFVBPXCTEDN-UHFFFAOYSA-N 0.000 claims description 3
- 238000007639 printing Methods 0.000 claims description 3
- 238000004804 winding Methods 0.000 claims description 3
- WABPQHHGFIMREM-UHFFFAOYSA-N lead(0) Chemical compound [Pb] WABPQHHGFIMREM-UHFFFAOYSA-N 0.000 abstract description 14
- 238000004364 calculation method Methods 0.000 abstract description 7
- 229910000831 Steel Inorganic materials 0.000 abstract description 5
- 238000009826 distribution Methods 0.000 abstract description 5
- 239000010959 steel Substances 0.000 abstract description 5
- 238000001514 detection method Methods 0.000 abstract description 3
- 238000003889 chemical engineering Methods 0.000 abstract description 2
- 238000004458 analytical method Methods 0.000 description 6
- 238000010586 diagram Methods 0.000 description 6
- 229910052799 carbon Inorganic materials 0.000 description 4
- 238000012545 processing Methods 0.000 description 4
- 238000009412 basement excavation Methods 0.000 description 3
- 230000008901 benefit Effects 0.000 description 3
- 238000010276 construction Methods 0.000 description 3
- 230000007547 defect Effects 0.000 description 3
- 238000005457 optimization Methods 0.000 description 3
- 238000013461 design Methods 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 238000002405 diagnostic procedure Methods 0.000 description 2
- 230000006698 induction Effects 0.000 description 2
- 239000004973 liquid crystal related substance Substances 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 230000004044 response Effects 0.000 description 2
- 238000004088 simulation Methods 0.000 description 2
- 238000000638 solvent extraction Methods 0.000 description 2
- 238000012546 transfer Methods 0.000 description 2
- NAWXUBYGYWOOIX-SFHVURJKSA-N (2s)-2-[[4-[2-(2,4-diaminoquinazolin-6-yl)ethyl]benzoyl]amino]-4-methylidenepentanedioic acid Chemical compound C1=CC2=NC(N)=NC(N)=C2C=C1CCC1=CC=C(C(=O)N[C@@H](CC(=C)C(O)=O)C(O)=O)C=C1 NAWXUBYGYWOOIX-SFHVURJKSA-N 0.000 description 1
- 229910000975 Carbon steel Inorganic materials 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 235000006629 Prosopis spicigera Nutrition 0.000 description 1
- 240000000037 Prosopis spicigera Species 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- 238000004220 aggregation Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000010962 carbon steel Substances 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 230000006870 function Effects 0.000 description 1
- 238000007689 inspection Methods 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 101150050759 outI gene Proteins 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 239000002689 soil Substances 0.000 description 1
- 238000005476 soldering Methods 0.000 description 1
- 238000000547 structure data Methods 0.000 description 1
- 239000008399 tap water Substances 0.000 description 1
- 235000020679 tap water Nutrition 0.000 description 1
Images
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y04—INFORMATION OR COMMUNICATION TECHNOLOGIES HAVING AN IMPACT ON OTHER TECHNOLOGY AREAS
- Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
- Y04S10/00—Systems supporting electrical power generation, transmission or distribution
- Y04S10/50—Systems or methods supporting the power network operation or management, involving a certain degree of interaction with the load-side end user applications
- Y04S10/52—Outage or fault management, e.g. fault detection or location
Landscapes
- Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)
Abstract
The invention provides a diagnosis device for corrosion of an earth screen of a large-size transformer substation. The diagnosis device comprises a distribution type collection box, a signal collection device, a movable calculation PC (personal computer) and a 3G (3rd Generation) wireless communication terminal, wherein the distribution type collection box is formed by a box body, a protection cover, binding posts and a measuring lead wire, wherein the protection cover detachably covers the box body; a plurality of binding posts are vertical in a mutually-insulating manner and pass through a bottom plate of the box body; the measuring lead wire is a two-core flexible lead core; one end of the measuring lead wire is electrically with the lower ends of the binding posts; and the other end of the measuring lead wire is welded with a lead-up wire of a grid node of the earth screen. The diagnosis device and the diagnosis method for the corrosion of the earth screen of the large-size transformer substation can be widely applied to corrosion fault detection of the earth screen of the transformer substation which is put into operation and are particularly suitable for the large-size transformer substation which has a larger occupied area and higher safety requirements. Furthermore, the diagnosis device and the diagnosis method for the corrosion of the earth screen of the large-size transformer substation can also be widely applied to other systems with the earth screens, such as steel, chemical engineering, a power plant and the like and have extremely great required amount and an extremely wide application prospect.
Description
Technical Field
The invention relates to a grounding grid corrosion diagnosis device, in particular to a portable grounding grid corrosion diagnosis device capable of detecting a substation grounding grid with a large floor area. The invention also relates to a diagnostic method using said diagnostic device.
Background
A large number of important electrical devices are concentrated in the substation, and a good grounding device is needed to meet the requirements of working grounding, protective grounding and lightning grounding. The practical earthing device for engineering is an earthing net, which is mainly a grid formed by welding flat steel, round steel, angle steel and the like. The performance of the transformer substation grounding grid is directly related to the safety of personnel and equipment in the substation. With the development of electric power systems in China, the grounding short-circuit current is gradually increased, and the requirement on the performance of a grounding grid is higher and higher. The foreign grounding grid conductors are mostly made of copper materials, the problem of corrosion faults is less, and due to the resource and economic consideration of China, the grounding grid conductors are mostly made of common carbon steel and can be corroded after being buried underground for years, particularly in regions with acidic coastal soil, the corrosion problem is more serious, and the grounding grid is easy to be electrically opened. Meanwhile, in combination with the corrosive excavation inspection condition of the grounding grid specified in the power row standard DL596-1996, the construction problems of work stealing, material reduction, conductor loss, insufficient soldering, missing welding and the like also often occur in the construction process of the grounding grid. The corrosion of the earth screen conductor and the careless omission of the construction link easily cause the change of the internal grounding parameters of the transformer substation, such as unqualified step voltage and contact potential in the transformer substation, and threaten the safety of personnel and the stable operation of equipment in the transformer substation.
The grounding grid is used as a concealed project and basically in a maintenance-free state after operation. The power row standard DL596-1996 and the south grid enterprise standard Q/CSG 10007-. Some new diagnostic methods and systems are also available at present, and a certain excitation is injected into a ground grid node according to a ground grid topological structure, and a detected response (voltage, magnetic field or the like) is subjected to mathematical tool analysis to obtain a ground grid fault condition. For example, in patent application No. 200710185685.1, "method and apparatus for diagnosing defects of grounding grid of transformer substation", the distribution of magnetic induction intensity on the ground surface is measured by injecting excitation signals, and then the measured result is compared with the normal state data calculated by simulation to judge the specific position and degree of the corrosion thinning or breaking defects of the grounding grid. The main disadvantages of the patent are: because the electromagnetic environment in the substation switch yard is very complicated, the magnetic induction intensity interference of detection is great, and the filtering design is very complicated, and the accuracy is difficult to improve. The patent application No. 201010586932.0 entitled "measuring device for diagnosing connection state of grounding grid" includes measuring circuit, central processing control circuit, and PC. The device takes the grounding rod as a carrier, inputs an excitation signal to the grounding rod, and obtains local connection information of the grounding grid through subsequent processing of the obtained output response signal. The main disadvantages of this patent are: the land grid of a large-scale transformer substation often occupies a large area, an extremely long measurement lead is required to frequently pull back and forth and replace a measurement point during field diagnosis and measurement, only one group of ports can be measured through one-time wiring, the workload is large, and serious potential safety hazards can exist when long-time measurement operation is carried out in a live-line area switch field of the transformer substation.
Disclosure of Invention
The invention aims to solve the first technical problem of providing a transformer substation grounding grid corrosion diagnosis device for a large-scale or even ultra-large-scale grounding grid, which can be moved, carried and networked in real time, is safe and simple to operate and can accurately detect fault defects without large-scale excavation.
The second technical problem to be solved by the invention is to provide a method for carrying out corrosion diagnosis on the transformer substation grounding grid of the large-scale or even ultra-large-scale grounding grid by using the device.
The technical scheme adopted by the invention for solving the first technical problem is as follows:
a corrosion diagnosis device for a ground screen of a large-scale transformer substation is characterized in that: the system comprises a distributed acquisition box, a signal acquisition device, a mobile computing PC and a 3G wireless communication terminal;
the distributed acquisition box comprises a box body, a protective cover, binding posts and a measurement lead, wherein the protective cover is detachably covered on the box body, the binding posts are mutually insulated and erected and penetrate through a bottom plate of the box body, the measurement lead is a two-core flexible conductor, one end of the measurement lead is electrically connected with the lower ends of the binding posts, and the other end of the measurement lead is welded with an upper lead of a grid node of a ground grid.
The box body of the distributed junction box is a disc shell, the thickness of the shell is 8 mm-18 mm, the height of the shell is 80 mm-180 mm, the diameter of the shell is 250 mm-600 mm, and the box body is made of ABS resin material; the safety cover be a hemisphere shell, the diameter with the box body unanimous, the shell is thick 8mm ~18 mm. When the distributed junction box is not used, the box body is covered on the box body to play a role in protection, and when the distributed junction box is used, the box body is taken down. The wiring terminal is a commercially available original, the waist hole of the panel is phi 7.0 mm-11 mm, the withstand current is 10-30A, the test withstand voltage is 3KV, and the wiring terminal is embedded on the panel of the box body.
The top of the wiring terminal is positioned outside the box body, the tail part of the wiring terminal is embedded into the panel of the box and is connected with a core in the upper end of the measuring lead, the top of the wiring terminal is represented by a reference numeral C and is connected with the current line, the top of the wiring terminal is represented by a reference numeral P and is connected with the voltage line, each pair of wiring terminals (P, C columns) is connected with the upper end of the measuring lead, the lower end of the corresponding measuring lead is connected to a grounding grid accessible node leading-up line in a grounding grid block distributed by the distributed concentrator, and the wiring terminals are marked according to the connected accessible node numbers.
The signal acquisition device is a commercially available micro-ohm meter and consists of a measuring range network, a Kelvin bridge, an A/D conversion module (AD574D), an open-circuit protection module, a serial communication interface and a printing module; the serial communication interface is a data interface based on the international EIA-RS-232C standard, the data transmission rate adopts a baud rate of 4800KB, and for data (information codes): the level of logic "1" (mark) is lower than-3V, the level of logic "0" (space) is higher than + 3V; for the control signal; the ON state (ON), i.e. the level at which the signal is active, is higher than +3V, and the OFF state (OFF), i.e. the level at which the signal is inactive, is lower than-3V, i.e. when the absolute value of the transmission level is higher than 3V, the circuit can effectively check that voltages between-3 and +3V are insignificant, and voltages lower than-15V or higher than +15V are also deemed insignificant. The corresponding PC control code S (S) is a single transmission command, i.e., the RS-232 interface transmits only one set of data, and the control code C (C) is a continuous transmission data command. The Kelvin bridge is formed by winding a resistance element by a manganese copper wire which is mature in process.
The mobile PC is a commercially available notebook computer; the 3G wireless communication terminal is a commercially available network card;
the memory of the notebook computer is more than or equal to 2GB, the processor is more than or equal to 1.5GHz, a Windows 764 bit operating system is adopted, the hard disk is more than 500GB, and the display card adopts an integrated display card 64MB for display memory or more.
The mobile computing PC is a commercially available notebook computer, the memory of the computer is 2GB or more, the processor is 1.5GHz or higher, a Windows 764-bit operating system is adopted, the hard disk is larger than 500GB, and the display card is integrated with 64MB of the display card for display memory or more. The large-capacity hard disk and the high-end memory are enough to ensure that the computer is competent for storing and analyzing data. All operation control can be realized through a touch control panel and a keyboard, and the operation of the equipment can be monitored in real time through a liquid crystal display, and various required information can be obtained.
The 3G wireless communication terminal is a network card, and is based on a China telecom CDMA 20001X network, a China Mobile TD-SCDMA/HSUPA network or a 3G network card of a Unicom HSDPA/UMTS/HSUPA network. The transmission speed of the 3G wireless communication terminal is more than 3.1Mbps at the downlink and more than 1.8Mbps at the uplink. The interface type is USB 2.0.
A large-scale transformer substation grounding grid corrosion diagnosis method adopting the diagnosis device comprises the following steps:
s1, the large-scale grounding grid is partitioned into different measuring areas, and each measuring area comprises a plurality of nodes;
s2 each node is provided with an upper lead wire, one upper lead wire is welded with a measuring lead wire, the welding position is coated with anti-corrosion paint for anti-corrosion protection, the measuring lead wire is a two-core flexible wire purchased in the market, and the nominal section of each core flexible wire is 1.2mm2~2.8mm2The two core flexible wires are respectively used as a current line and a voltage line; (all nodes have leading-in wires, all leading-in wires are welded with measuring leads)
S3 measurement leads are led out and horizontally arranged with a burial depth of 200 mm-300 mm, and finally all the measurement leads are converged on binding posts of a distributed concentrator box for centralized measurement, the binding posts are connected with one core of two-core flexible lead measurement leads, the reference number C is used for connecting with the current line, the reference number P is used for connecting with the voltage line, each pair of the binding posts (P, C columns) is connected with one measurement lead, and the distributed concentrator box is arranged at the edge of a ground grid;
s4, data measurement is carried out on any two pairs of binding posts on the junction box by using a signal acquisition device, and ports of corresponding ground network nodes connected with the measurement lead wires are equivalently measured, namely, a field stay wire measurement mode in a switch field area of a large-scale transformer substation is replaced.
The S4 is as follows: the measured resistor (ground net port) is connected into a double-arm Kelvin bridge of a micro-ohm meter of the signal acquisition device in a four-terminal method, current excitation is injected through the current line, and voltage is measured by the voltage line so as to calculate the corresponding port resistance.
The wiring measurement mode of the invention can transfer the wire resistance and the contact resistance to a power supply circuit, and because the bridge arm resistance of the Kelvin bridge is much larger than the corresponding additional resistance, the additional resistance can be ignored, and the influence of the wire resistance and the contact resistance on the resistance to be measured is eliminated.
The measuring range network is used for converting different measuring ranges of the Kelvin bridge, the measuring ranges meet 1m omega-2000 m omega, and the resolution ratio meets 1 mu omega. The signal acquisition device measures any pair of the ground network lead-up wire port pairs, then carries out resistance voltage conversion, converts the resistance voltage into a digital signal through A/D (analog/digital) and can directly communicate with the mobile computer through an RS232 communication interface.
The distributed concentrator is used for concentrating the measuring leads in all the distributed ground grid blocks for centralized measurement.
The distributed line concentration box and the measuring lead are well installed and fixed at one time for multiple measurements in the future.
Principle of diagnosis
The grounding grid of an actual transformer substation is complex, and the following processing and assumptions are made for the grounding grid in order to facilitate data input and establishment of mathematical equations:
the natural grounding body of the grounding grid, such as a tap water pipe, a distribution device framework foundation, an overhead lightning conductor led into the distribution device framework, a cable bracket, a metal sheath of a cable and the like, is not considered.
Secondly, supposing that the connection points of the grounding lead and the grounding grid are all on the nodes of the horizontal branch of the grounding grid;
according to the circuit principle:
（2.4）
by a correlation matrixAExpressed as KCL and KVL equations of
Thereby obtaining the port resistanceR ij ：
According to the circuit principle, if the structure of any N-terminal network, the resistance of branches and the excitation condition can be known, the port resistance can be obtained according to a node analysis method. But for fault diagnosis is made ofR ij Resistance of branch of grounding gridR k It can be seen that it is the inverse of the circuit computation.
Establishment of fault diagnosis equation
The model diagram of the grounding grid before corrosion is regarded as a graph withbThe number of the branches is +1,nnetwork N of +1 nodes. Wherein, the firstbWith +1 branches connected to earth networki，jAnd (4) an end. On the earth gridi，jThe port is provided with a current source with a current value ofI 0Can be obtained from the circuit principleR ij ；
When the grounding grid is corroded, the model diagram is regarded as a network N ', and the network N' is still positioned in the model diagrami，jA terminal current source with a current value ofI 0. Find outR′ ij (ii) a It can be seen that the network N and the network N' have the same topology.
When network branchkWhen corrosion or a crack occurs, the corrosion or crack occurs,branch resistance thereofR k Become intoR′ k Namely:
port resistance of the network at this timeR ij Become intoR′ ij Namely:
（2）
according to the Taylor theorem:
（3）
because of the presence of two networksi，jAt the end ofbThe +1 branches all have currents ofI 0Namely:
（6）
（7）
substituting the formula (3) and the formula (4) to obtain:
equation (9) is subtracted from equation (8) to yield:
（10）
formula (1) and formula (2) are substituted for formula (10):
thus, the relationship between the port resistance variation value and the branch resistance variation value is obtainedHowever, the branch resistance variation value cannot be directly obtained from the port resistance variation value because the variable number of the branch resistance hasbTherefore, a series of port resistances are measured to obtain a set of equations:
（13）
wherein,mis the number of ports to be measured,I k can be prepared fromR k Thus obtaining the product.
WhileI′ k ByR′ k Determine, butR′ k Unknown, so the equations cannot be solved yet at this time.
It can be seen from equation (13) that the system of equations is nonlinear and cannot be directly solved.
To solve the problem, an iterative method is introduced. First, letI′ k (0)= I k The system of equations becomes a system of linear equations, butm＜bThe system of equations is underdetermined and needs to be solved by an optimization method, and a quasi-Newton method is used in the method. Thus, Δ is obtainedR k (0) AndR′ k (0) followed byR′ k (0) Calculate outI′ k (1) (ii) a Then useI′ k (1) ComputingR′ k (1). And repeating the above calculation until the obtained resistance increment meets the requirement to obtain the final calculation result. According to the theory, the corresponding diagnostic program is obtained through software programming.
However, for large and medium-sized ground grids, the occupied area of the transformer substation ground grid is large, the number of down-lead wires connected with the ground grid is large, all measurements cannot be carried out, a ground grid block measurement scheme can be adopted, and the results obtained by selecting appropriate measurement point measurement data in small blocks for calculation and analysis through test simulation have high accuracy.
The invention has the beneficial effects that:
the electric quantity of the node port of the earth screen of the large-scale transformer substation is directly measured at the measuring line terminal to replace the situation that the electric substation enters a live transformer substation switch yard to carry out large-span stay wire measurement, so that complicated operation procedures such as work ticket issuing are omitted, the regular repeated measurement is simple and convenient, the workload is low, and the safety risk of the measurement work is reduced.
Secondly, the large-scale transformer substation occupies a large area, the equipment arrangement is complex, and the accuracy and the positioning difficulty are high. The distributed line concentration box can conveniently divide a large-scale ground net into blocks, and is directly used for measuring, so that the accuracy of measured data can be improved, and the measuring efficiency is greatly improved.
The invention can find the corrosion fault of the grounding grid and the development condition of the fault in advance, position and safely evaluate the corrosion fault of the grounding grid, realize the nondestructive detection diagnosis of the transformer substation, and compared with the traditional method for searching the breakpoint and the corrosion section of the grounding grid by large-area power failure excavation, the method provided by the system has the advantages of high pertinence, high speed, simple and portable equipment, the measured data is directly input into the data processing host for analysis, the obtained result can be immediately shared, output and stored, and the like, and the normal operation of the power system is not influenced, so that the safe operation and the power supply reliability of the power system are ensured, the good image of the power system in each industry is directly established, and the indirect economic benefit and the social benefit are also very great.
The invention can be widely used for detecting corrosion faults of the grounding grid of the transformer substation which is put into operation, and is particularly suitable for large-scale transformer substations which have larger occupied area and higher safety requirements. In addition, the research result can also be applied to other systems with ground nets, such as steel, chemical engineering, power plants and the like, the demand is extremely high, and the application prospect is extremely wide.
Drawings
FIG. 1 is a schematic diagram of the structural principle of the diagnostic device of the present invention;
FIG. 2 is a schematic diagram of a distributed cluster box with the protective cover removed;
FIG. 3 is a side view of a distributed cluster box with a protective cover;
fig. 4 is a layout diagram of the distributed junction box and the ground grid to be tested.
In the figure: 1 terminal, 2 box bodies, 3 measurement lead wires, 4 electric current lines that link to each other with signal acquisition device, 5 voltage lines that link to each other with signal acquisition device, 6 safety covers, 7 distributed concentrator boxes, 8 large-scale earth mat that awaits measuring.
Detailed Description
The invention is further illustrated with reference to the following figures and examples.
Fig. 1 to 4 show an embodiment of a corrosion diagnosis device for a ground grid of a large-scale substation, which mainly comprises a distributed acquisition box, a signal acquisition device, a mobile computing PC and a 3G wireless communication terminal.
Referring to fig. 2 and 3, the distributed junction box is composed of a box body, a protective cover, binding posts and a measuring lead, wherein the protective cover is detachably covered on the box body, the binding posts are mutually insulated and erected and penetrate through a bottom plate of the box body, the measuring lead is a two-core flexible conductor, one end of the measuring lead is electrically connected with the lower ends of the binding posts, and the other end of the measuring lead is welded with a lead of a grid node of a ground grid.
Distributed line concentrator box body is the disc shell, and 8mm ~18mm of shell thickness is 80mm ~180mm highly, and the diameter is 250mm ~600mm, and the box body material adopts ABS resin material to make, and the safety cover is a hemisphere shell, and the diameter is unanimous with the box body, and the shell thickness is 8mm ~18 mm. When the distributed junction box is not used, the distributed junction box covers the box body to play a role in protection, and is taken down when used, the wiring terminal is a commercially available original, the waist hole of the panel is phi 7.0 mm-11 mm, the withstand current is 10-30A, the test withstand voltage is 3KV, and the distributed junction box is embedded on the panel of the box body.
The top of the wiring post is positioned outside the box body, the tail part of the wiring post is embedded into the panel of the box and is connected with a core in the upper end of the measuring lead, the tail part of the wiring post is represented by a reference numeral C and is connected with a current line, the tail part of the wiring post is represented by a reference numeral P and is connected with a voltage line, each pair of wiring posts (P, C posts) are connected with one measuring lead, the lower end of the corresponding measuring lead is connected to a grounding grid accessible node lead in a grounding grid block distributed by the distributed concentrator, and the wiring posts are marked according to the connected accessible node numbers.
And partitioning the large grounding grid, namely dividing the large grounding grid into different measurement areas, wherein each area is assigned with one distributed junction box, and the distributed junction boxes are arranged at the edge of the grounding grid.
The measuring lead is a commercially available two-core flexible conductor, the nominal section of each flexible conductor is 1.2mm2, each flexible conductor is respectively used as a current line and a voltage line to be welded on a lead-up wire connected with a horizontal grounding grid node, and the welding position is coated with anticorrosive paint for anticorrosive protection. And one measuring lead is only connected with one lead-up wire, is horizontally arranged with the embedding depth of 200mm after being led out from the welding point, and finally is completely gathered in the box body.
The distributed aggregation box functions to aggregate the measurement leads in all of the assigned counterpoise segments for centralized measurement. Through data measurement of any two pairs of binding posts on the junction box, ports of corresponding grounding grid nodes connected with the measuring lead are equivalently measured, namely, a mode of field stay wire measurement in a switch field area of a large-scale transformer substation is replaced.
The distributed line concentration box and the measuring lead are well installed and fixed at a uniform time for multiple measurements at a later date.
The signal acquisition device is a commercial direct current resistance instrument such as a CT3010 tester of Hangzhou high-voltage electric company, and comprises a Kelvin bridge, an A/D conversion module (AD574D), an open-circuit protection module, a serial communication interface, a measuring range network and a printing module. The serial communication interface is a data interface based on the international EIA-RS-232C standard, the data transmission rate adopts a baud rate of 4800KB, and for data (information codes): the level of logic "1" (mark) is lower than-3V, the level of logic "0" (space) is higher than + 3V; for the control signal; the ON state (ON), i.e. the level at which the signal is active, is higher than +3V, and the OFF state (OFF), i.e. the level at which the signal is inactive, is lower than-3V, i.e. when the absolute value of the transmission level is higher than 3V, the circuit can effectively check that voltages between-3 and +3V are insignificant, and voltages lower than-15V or higher than +15V are also deemed insignificant. The corresponding PC control code S (S) is a single transmission command, i.e., the RS-232 interface transmits only one set of data, and the control code C (C) is a continuous transmission data command.
The Kelvin bridge is formed by winding a resistance element by a manganese copper wire which is mature in process. The measured resistance (counterpoise port) is connected in a four-terminal method in a two-arm bridge, excited by current injected through a current line, and the voltage measured by a voltage line is used to calculate the corresponding port resistance. The wiring measurement mode can transfer the wire resistance and the contact resistance to a power supply circuit, and the bridge arm resistance is much larger than the corresponding additional resistance, so that the additional resistance is ignored, and the influence of the wire resistance and the contact resistance on the resistance to be measured is eliminated.
The measuring range network is used for converting different measuring ranges of the Kelvin bridge, the measuring range meets 1m omega-2000 m omega, and the resolution meets 1 mu omega.
The signal acquisition device measures any pair of the earth network lead-up wire port pairs, then carries out resistance voltage conversion, converts the resistance voltage into a digital signal through A/D (analog/digital) and can directly communicate with the mobile computer through an RS232 communication interface.
The mobile computing PC is a commercially available notebook computer, the memory of the computer adopts 2GB, the processor adopts i3-2330M 2.2GHz, the Windows 764 bit operating system, the hard disk 500GB and the display chip AMD Radon HD 6630M are adopted, and the display capacity is 1 GB. The large-capacity hard disk and the high-end memory are enough to ensure that the computer is competent for storing and analyzing data. All operation control can be realized through a touch control panel and a keyboard, and the operation of the equipment can be monitored in real time through a liquid crystal display, and various required information can be obtained.
The 3G wireless communication terminal is a Huashi (HUAWEI) EC 1223G wireless network card, the data transmission rate is 3.1Mbps downlink and 1.8Mbps uplink, the 3G wireless communication terminal is based on a China telecom CDMA 20001X network, and the interface type is USB 2.0.
The diagnosis method adopting the large-scale transformer substation grounding grid corrosion diagnosis device comprises the following steps:
s1, inputting the topological structure data of the actual grounding grid into a mobile computing PC, selecting a measurement scheme according to the size and shape of the grounding grid to measure the required grounding grid port data, and partitioning the large grounding grid into different measurement areas, wherein each measurement area comprises a plurality of nodes;
s2, each node is provided with an upper lead wire, one upper lead wire is welded with a measuring lead wire, the welding position is coated with anticorrosive paint for anticorrosive protection, the measuring lead wire is a commercially available two-core flexible lead wire, the nominal section of each core flexible lead wire is 1.2mm 2-2.8 mm2, and the two-core flexible lead wires are respectively used as a current wire and a voltage wire; (all nodes have leading-in wires, all leading-in wires are welded with measuring leads)
S3 measurement leads are led out and horizontally arranged with a burial depth of 200 mm-300 mm, and finally all the measurement leads are converged on binding posts of a distributed concentrator box for centralized measurement, the binding posts are connected with one core of two-core flexible lead measurement leads, the reference number C is used for connecting with the current line, the reference number P is used for connecting with the voltage line, each pair of the binding posts (P, C columns) is connected with one measurement lead, and the distributed concentrator box is arranged at the edge of a ground grid;
s4, carrying out data measurement on any two pairs of binding posts on the junction box by using a signal acquisition device, equivalently measuring the ports of corresponding ground network nodes connected with the measurement lead, namely replacing a field stay wire measurement mode in the switch field area of a large-scale transformer substation; the method specifically comprises the following steps:
the measured resistance (ground net port) is connected into a double-arm Kelvin bridge of a micro-ohm meter of a signal acquisition device by a four-terminal method, a current line 4 and a voltage line 5 which are connected with the signal acquisition device are connected onto a pair of binding posts 1 on a distributed concentrator 7, direct current excitation of 5A is applied to measure the port resistance of the corresponding ground net node pair, and the measured resistance parameter signal is transmitted to a mobile computing PC through an RS-232 communication interface in the signal measurement and acquisition device 5. Data are collected on different distributed line concentration boxes 7 in sequence;
and after the data is summarized by the measurement software, the corrosion fault condition is obtained through calculation and analysis, the corrosion fault branch is positioned, and the information can be transmitted with a superior department system through the 3G wireless communication terminal or the corresponding diagnosis result can be printed and output.
The following steps of the overall calculation process are as follows
1) Obtaining topological structure and branch resistance of grounding grid from design drawing
(ii) a Calculated according to circuit principles
Selecting some measuring node groups to calculate the resistance between theoretical nodes
(s＝1～m)；
2) Measuring port resistance
Calculating the port resistance variation value
；
3) Order to
；
4) Using the system of equations (1)0) Calculated in combination with an optimization method
(t is 0, 1.. and t is the number of iterations); then calculate out
；
5) If it is notAnd alsoThen the iterative calculation is stopped, and it is consideredIn the end result of this, the result is,
is a set constant; otherwise, continuing the next step;
6) By using
Computing
(ii) a And (4) repeating the step (4).
Since the number of unknown quantities in the equation set (10) is b, the number of equations should be b to obtain accurate values of the variables, but the value of b is very large, and since the number of grounding leads of a general substation is less than the number of branches of a grounding grid, it is not possible to perform multiple measurements in engineering. In order to obtain a good accurate value, an optimization technique is required:
(14)
s.t. 
(k =1，2，...，b)
and calculating and analyzing by measurement software to obtain the corrosion fault condition, positioning the corrosion fault branch, and outputting and storing the analysis result for further research and maintenance.
Claims (4)
1. A corrosion diagnosis device for a ground screen of a large-scale transformer substation is characterized in that: the system comprises a distributed acquisition box, a signal acquisition device, a mobile computing PC and a 3G wireless communication terminal;
the distributed acquisition box comprises a box body, a protective cover, binding posts and a measurement lead, wherein the protective cover is detachably covered on the box body, the binding posts are mutually insulated and erected and penetrate through a bottom plate of the box body, the measurement lead is a two-core flexible conductor, one end of the measurement lead is electrically connected with the lower ends of the binding posts, and the other end of the measurement lead is welded with an upper lead of a grid node of a ground grid.
2. The large-scale substation grounding grid corrosion diagnosis device according to claim 1, characterized in that: the box body of the distributed junction box is a disc shell, and the box body is made of ABS resin material; the protective cover is a hemispherical shell, and the diameter of the protective cover is consistent with that of the box body; the wiring terminals are commercially available original pieces, the waist hole of the panel is phi 7.0mm to 11mm, the withstand current is 10A to 30A, the test withstand voltage is 3KV, the top of each wiring terminal is positioned outside the box body, the tail part of each wiring terminal is embedded into the panel of the box and connected with a core in the upper end of a measuring lead, the core is denoted by a reference numeral C and connected with a current line and a voltage line, each pair of wiring terminals is connected with one measuring lead, the lower end of each corresponding measuring lead is connected to a grounding grid reachable node lead in a grounding grid block distributed by the distributed concentrator, and the wiring terminals are marked according to the connected reachable node numbers; the signal acquisition device is a commercially available micro-ohm meter and consists of a measuring range network, a Kelvin bridge, an A/D conversion module (AD574D), an open-circuit protection module, a serial communication interface and a printing module; the serial communication interface is a data interface based on the international EIA-RS-232C standard, the data transmission rate of the serial communication interface adopts a baud rate of 4800KB, and the Kelvin bridge is formed by winding a resistor element by a manganese copper wire with a mature process; the mobile PC is a commercially available notebook computer; the 3G wireless communication terminal is a commercially available network card; the memory of the notebook computer is more than or equal to 2GB, the processor is more than or equal to 1.5GHz, a Windows 764 bit operating system is adopted, the hard disk is more than 500GB, and the display card adopts an integrated display card 64MB for display memory or more.
3. A method for diagnosing corrosion of a metro network of a large-scale substation using the apparatus for diagnosing corrosion of a metro according to claim 1 or 2, comprising the steps of:
s1, the large-scale grounding grid is partitioned into different measurement areas, and each measurement area comprises a plurality of nodes;
s2 each node is provided with a leading wire, and one leading wire is welded with a measuring leading wireThe welding position is coated with anticorrosive paint for anticorrosive protection, the measuring lead is a commercially available two-core flexible conductor, and the nominal section of each core flexible conductor is 1.2mm2~2.8mm2The two core flexible wires are respectively used as a current line and a voltage line;
s3 the measuring lead is led out and then horizontally arranged with a burial depth of 200 mm-300 mm, and finally all the measuring lead is converged on a binding post of a distributed concentrator box for centralized measurement, wherein the binding post is connected with one of the two flexible lead measuring leads, the core is connected with the current line by the reference numeral C, the binding post is connected with the voltage line by the reference numeral P, each pair of the binding posts is connected with one of the measuring leads, and the distributed concentrator box is arranged at the edge of a ground grid;
s4, data measurement is carried out on any two pairs of binding posts on the junction box by using a signal acquisition device, and ports of corresponding ground network nodes connected with the measurement lead wires are equivalently measured, namely, a field stay wire measurement mode in a switch field area of a large-scale transformer substation is replaced.
4. The method for diagnosing corrosion of the ground grid of the large-scale substation according to claim 3, wherein the method comprises the following steps: the step S4 is: the measured resistor is connected into a double-arm Kelvin bridge of a micro-ohm meter of the signal acquisition device in a four-terminal method, current excitation is injected through the current line, and voltage is measured by the voltage line so as to calculate the corresponding port resistor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201210121584.9A CN102707191B (en) | 2012-04-24 | 2012-04-24 | Diagnosis device and diagnosis method for corrosion of earth screen of large-size transformer substation |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201210121584.9A CN102707191B (en) | 2012-04-24 | 2012-04-24 | Diagnosis device and diagnosis method for corrosion of earth screen of large-size transformer substation |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN102707191A true CN102707191A (en) | 2012-10-03 |
| CN102707191B CN102707191B (en) | 2014-09-24 |
Family
ID=46900123
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201210121584.9A Active CN102707191B (en) | 2012-04-24 | 2012-04-24 | Diagnosis device and diagnosis method for corrosion of earth screen of large-size transformer substation |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN102707191B (en) |
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103439629A (en) * | 2013-08-05 | 2013-12-11 | 国家电网公司 | Power distribution network fault diagnosis system based on data grid |
| CN104142455A (en) * | 2014-08-20 | 2014-11-12 | 国家电网公司 | Grounding grid corrosion fault diagnosis method based on Tellegen theorem |
| CN104678183A (en) * | 2015-03-23 | 2015-06-03 | 重庆大学 | Grounding grid branch circuit resistance detection method based on++-shaped detection unit |
| CN104678229A (en) * | 2015-03-24 | 2015-06-03 | 国家电网公司 | Substation grounding grid corrosion monitoring system |
| CN104937554A (en) * | 2013-01-22 | 2015-09-23 | 通用电气公司 | Systems and methods for analyzing data in a non-destructive testing system |
| CN105445615A (en) * | 2015-11-12 | 2016-03-30 | 有能集团有限公司 | Corrosion diagnosis method for transformer station grounding network |
| CN105823933B (en) * | 2016-03-21 | 2018-09-18 | 南京信息职业技术学院 | Infinitesimal segmentation detection method for corrosion detection of transformer substation grounding grid |
| CN109580463A (en) * | 2018-11-22 | 2019-04-05 | 国网天津市电力公司电力科学研究院 | A method of measurement ground net corrosion degree |
| CN111830362A (en) * | 2019-04-18 | 2020-10-27 | 中国石油化工股份有限公司 | Non-excavation detection method suitable for grounding grid of oil field tank field |
| CN111830361A (en) * | 2019-04-18 | 2020-10-27 | 中国石油化工股份有限公司 | Oil field tank field grounding grid fault detection device |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2098690U (en) * | 1991-08-06 | 1992-03-11 | 浙江省送变电工程公司 | Ultra-low frequency microcomputer type grounding resistance measuring instrument |
| WO1993019379A1 (en) * | 1992-03-19 | 1993-09-30 | Electronic Development, Inc. | Apparatus and method for measuring ground to earth impedance |
| CN1245898A (en) * | 1999-07-02 | 2000-03-01 | 清华大学 | Diagnosis method of earth screen corrosion and breakpoint of electric substation and its measurement and diagnosis system |
| JP2001116792A (en) * | 1999-10-14 | 2001-04-27 | Chubu Electric Power Co Inc | Method and apparatus for locating fault direction of power distribution line, and electric field and magnetic field sensors |
| CN101216523A (en) * | 2007-12-28 | 2008-07-09 | 华北电力大学 | Substation grounding net defect diagnostic method and apparatus |
| CN102095999A (en) * | 2010-12-14 | 2011-06-15 | 重庆大学 | Measuring device for diagnosing connecting state of grounding network |
| CN202794430U (en) * | 2012-04-24 | 2013-03-13 | 广东电网公司电力科学研究院 | Diagnosis device for corrosion of earth screen of large-size transformer substation |
-
2012
- 2012-04-24 CN CN201210121584.9A patent/CN102707191B/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2098690U (en) * | 1991-08-06 | 1992-03-11 | 浙江省送变电工程公司 | Ultra-low frequency microcomputer type grounding resistance measuring instrument |
| WO1993019379A1 (en) * | 1992-03-19 | 1993-09-30 | Electronic Development, Inc. | Apparatus and method for measuring ground to earth impedance |
| CN1245898A (en) * | 1999-07-02 | 2000-03-01 | 清华大学 | Diagnosis method of earth screen corrosion and breakpoint of electric substation and its measurement and diagnosis system |
| JP2001116792A (en) * | 1999-10-14 | 2001-04-27 | Chubu Electric Power Co Inc | Method and apparatus for locating fault direction of power distribution line, and electric field and magnetic field sensors |
| CN101216523A (en) * | 2007-12-28 | 2008-07-09 | 华北电力大学 | Substation grounding net defect diagnostic method and apparatus |
| CN102095999A (en) * | 2010-12-14 | 2011-06-15 | 重庆大学 | Measuring device for diagnosing connecting state of grounding network |
| CN202794430U (en) * | 2012-04-24 | 2013-03-13 | 广东电网公司电力科学研究院 | Diagnosis device for corrosion of earth screen of large-size transformer substation |
Non-Patent Citations (3)
| Title |
|---|
| 刘渝根等: "接地网故障诊断平台的功能与构建研究", 《高压电器》 * |
| 刘渝根等: "接地网腐蚀诊断优化测量方法", 《重庆大学学报》 * |
| 王萍等: "变电站接地网实时监测系统的开发与应用", 《电工技术》 * |
Cited By (17)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111832756A (en) * | 2013-01-22 | 2020-10-27 | 通用电气公司 | System and method for analyzing data in a non-destructive testing system |
| CN104937554A (en) * | 2013-01-22 | 2015-09-23 | 通用电气公司 | Systems and methods for analyzing data in a non-destructive testing system |
| US10387237B2 (en) | 2013-01-22 | 2019-08-20 | General Electric Company | Systems and methods for analyzing data in a non-destructive testing system |
| CN103439629A (en) * | 2013-08-05 | 2013-12-11 | 国家电网公司 | Power distribution network fault diagnosis system based on data grid |
| CN103439629B (en) * | 2013-08-05 | 2016-11-02 | 国家电网公司 | Fault Diagnosis of Distribution Network systems based on data grids |
| CN104142455A (en) * | 2014-08-20 | 2014-11-12 | 国家电网公司 | Grounding grid corrosion fault diagnosis method based on Tellegen theorem |
| CN104678183A (en) * | 2015-03-23 | 2015-06-03 | 重庆大学 | Grounding grid branch circuit resistance detection method based on++-shaped detection unit |
| CN104678183B (en) * | 2015-03-23 | 2017-08-25 | 重庆大学 | A kind of grounded screen branch resistance detection method based on Lv type detection units |
| CN104678229B (en) * | 2015-03-24 | 2017-10-10 | 国家电网公司 | A kind of grounding net of transformer substation corrosion monitoring system |
| CN104678229A (en) * | 2015-03-24 | 2015-06-03 | 国家电网公司 | Substation grounding grid corrosion monitoring system |
| CN105445615A (en) * | 2015-11-12 | 2016-03-30 | 有能集团有限公司 | Corrosion diagnosis method for transformer station grounding network |
| CN105823933B (en) * | 2016-03-21 | 2018-09-18 | 南京信息职业技术学院 | Infinitesimal segmentation detection method for corrosion detection of transformer substation grounding grid |
| CN109580463A (en) * | 2018-11-22 | 2019-04-05 | 国网天津市电力公司电力科学研究院 | A method of measurement ground net corrosion degree |
| CN111830362A (en) * | 2019-04-18 | 2020-10-27 | 中国石油化工股份有限公司 | Non-excavation detection method suitable for grounding grid of oil field tank field |
| CN111830361A (en) * | 2019-04-18 | 2020-10-27 | 中国石油化工股份有限公司 | Oil field tank field grounding grid fault detection device |
| CN111830362B (en) * | 2019-04-18 | 2021-10-29 | 中国石油化工股份有限公司 | Non-excavation detection method suitable for grounding grid of oil field tank field |
| CN111830361B (en) * | 2019-04-18 | 2022-04-22 | 中国石油化工股份有限公司 | Method for detecting corrosion fault of grounding grid of oil field tank field |
Also Published As
| Publication number | Publication date |
|---|---|
| CN102707191B (en) | 2014-09-24 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN102707191A (en) | Diagnosis device and diagnosis method for corrosion of earth screen of large-size transformer substation | |
| KR101131826B1 (en) | Wireless u-resistivity survey system | |
| CN201081764Y (en) | Remote soil resistivity monitor | |
| CN202453451U (en) | Earth grid corrosion and broken point diagnosing system for large and medium-sized substations | |
| CN102221644A (en) | System and method for online monitoring grounding networks of power stations and substations | |
| CN204536448U (en) | A kind of high voltage supply leakage conductor wireless monitoring device | |
| CN107462802B (en) | State evaluation method for 500kV underground substation grounding system | |
| CN106706715A (en) | Polluted soil detection method based on three-dimensional high-density electrical resistivity method | |
| CN107478909A (en) | A kind of smart grounding resistance on-line computing model and its system | |
| CN116780758A (en) | On-line monitoring system and method for multi-sensor data fusion of power transmission line | |
| CN109459467B (en) | Internet of things system for remotely monitoring soil environment and corrosivity in situ | |
| CN118091321A (en) | Method and device for detecting corrosion of grounding grid of power transmission line | |
| CN110780151A (en) | Large-scale grounding grid multi-channel rapid corrosion detection and plane imaging diagnosis method | |
| WO2024119965A1 (en) | Electrical monitoring system and method for hidden mine water hazards | |
| CN102645616A (en) | Fault addressing method for transmission line | |
| Liu et al. | Optimized corrosion diagnosis of large-scale grounding grid | |
| Guo et al. | Controlled large-scale tests of practical grounding electrodes—Part I: Test facility and measurement of site parameters | |
| CN205139294U (en) | Ground net corrodes situation testing arrangement based on wireless sensor network | |
| CN105158633B (en) | The method of UHVDC Arrester state on-line checking data is shared with cloud platform | |
| CN207964994U (en) | Grounding net of transformer substation health status detection device | |
| CN110749777A (en) | Soil resistivity measuring method | |
| CN109557380A (en) | A kind of oil gas library ground resistance on-Line Monitor Device | |
| CN205027414U (en) | Dam body hydrostatic level normal position automatic monitoring system | |
| CN111830361B (en) | Method for detecting corrosion fault of grounding grid of oil field tank field | |
| Guo et al. | Experimental investigation into the performance of large-scale earthing electrodes |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant |