CN111830362A - Non-excavation detection method suitable for grounding grid of oil field tank field - Google Patents
Non-excavation detection method suitable for grounding grid of oil field tank field Download PDFInfo
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Abstract
The invention discloses a trenchless detection method suitable for an oil field tank field grounding grid, and belongs to the technical field of power system safety diagnosis. The technical scheme is as follows: a non-excavation detection method suitable for an oil field tank field grounding grid is provided, and the detection method comprises the following steps: drawing a topological structure diagram according to a construction diagram of the tank area grounding grid, carrying out node numbering and branch numbering on the tank area grounding grid, generating a correlation node matrix, sequentially measuring the resistance, the contact resistance and the port resistance of the auxiliary lead, and calculating by using the measured resistance, the contact resistance and the port resistance of the auxiliary lead by using a corrosion fault detection program to obtain a corrosion detection result. The invention has the beneficial effects that: the method can avoid blind excavation, has a simple node and branch numbering method, can improve the diagnosis precision, reduces the detection time consumption, shortens the length of a measuring lead, reduces the error influence of contact resistance on branch resistance inverse operation, and greatly improves the diagnosis precision.
Description
Technical Field
The invention relates to the technical field of power system safety diagnosis, in particular to a trenchless detection method suitable for an oil field tank field grounding grid.
Background
The tank field grounding grid is a main channel for releasing lightning current, and is a basic measure for ensuring the lightning protection safety of the tank field. If the grounding grid is corroded and broken seriously, the grounding resistance is increased, and the ground potential is distributed unevenly, the lightning current or the lightning static induction charge is discharged into the ground at a speed obviously reduced, spark discharge or high-potential counterattack is generated among metal accessories of the storage tank, and oil gas is ignited and detonated to cause serious safety accidents and loss. At present, methods for detecting corrosion faults of a grounding grid mainly include excavation detection and non-excavation detection, wherein the method adopted for detecting the corrosion faults of the grounding grid in a tank area is generally earth breaking excavation, the method cannot accurately judge the condition of the grounding grid, and after the ground grid is unqualified in grounding resistance or an accident caused by the grounding grid occurs, the method for searching the breakpoints and the corrosion sections of the conductors of the grounding grid through large-area excavation has blindness and great workload, and also influences the safe operation of a power system. In addition, the existing grounding grid corrosion fault trenchless detection method is generally applied to the substation grounding grid, and the corrosion fault parameter identification method is more applied to the trenchless detection method, and the method is to perform inverse operation on branch resistance by measuring port resistance to obtain the change value of the branch resistance. When the tank area grounding grid is subjected to trenchless detection by using a corrosion fault parameter identification method, firstly, a corresponding topological structure is constructed according to the actual structure of the grounding grid, nodes and branches of the topological structure are numbered, parameters such as a correlation node matrix of the grounding grid are obtained, the numbering rules of the nodes and the branches have certain influence on the precision of inverse operation of the branches, and at present, no systematic numbering rules aiming at the nodes and the branches of the topological structure of the tank area grounding grid exist. In addition, because the constraint conditions of the branch circuits and the accessible nodes are few, the traditional transformer substation grounding grid port resistance measurement scheme cannot meet the port measurement requirement of the tank field grounding grid. Meanwhile, when corrosion fault parameter identification method is used for detecting corrosion fault of the tank area grounding grid, the contact resistance of the measuring port and the down lead of the grounding grid greatly influences the result of the branch resistance inverse operation, so that how to reduce or eliminate the influence of the contact resistance is also the problem to be solved urgently in the non-excavation detection of the corrosion fault of the tank area grounding grid.
The topological structure of the existing transformer substation grounding grid is usually a mesh structure, the node numbering rules are numbering sequences which are sequentially increased from left to right and from top to bottom, some of the numbering rules of the branches are that transverse branch numbering is compiled first, then longitudinal branch numbering is compiled, the transverse branch numbering is sequentially increased from left to right and from top to bottom, the tank field grounding grid is usually an annular grounding grid, conductors are not arranged according to the horizontal and vertical rules, and therefore the numbering sequences of the nodes and the branches cannot completely refer to the transformer substation grounding grid. In the port resistance measurement scheme, a large span measurement method, a block measurement method, or the like is generally used. The large-span measurement method generally selects two accessible nodes with large span as measurement ports, selects a plurality of large-span ports to carry out port resistance measurement, brings the port resistance measurement into a corrosion detection operation program, selects nodes at two ends of a branch with the most resistance increase multiple in a detection result as nodes for next port measurement, brings the node into a corrosion fault detection program after the measurement, and repeats for several times until a corrosion detection result is stable. The block measurement method is to divide the grounding grid into a plurality of areas, and then apply a large-span measurement method in each area to bring in a corrosion fault detection program, and finally obtain a stable corrosion diagnosis result. At this time, if the above method is applied to the tank field grounding grid corrosion detection, the following problems may be caused:
1) the nodes and the branches cannot be numbered, parameters such as a relevant node matrix cannot be obtained, and therefore inverse operation of branch resistance cannot be performed.
2) The final result cannot be directly obtained by one input. The two ends of the port with the largest resistance increase multiple of the last diagnosis result are selected for measurement in each measurement port, so the step of measurement → calculation needs to be repeated, and the time is delayed.
3) Measurement ports are typically spaced far apart, thus requiring a high length of measurement wire, and being lengthy and time consuming to wire in the field.
4) Because the contact resistance is usually tens of milliohms, the tank area grounding grid is usually not large, and the port resistance is also tens of milliohms, the influence of errors is large, and the result of the inverse operation of the branch resistance is far larger than the actual value.
How to solve the above technical problems is the subject of the present invention.
Disclosure of Invention
In order to solve the problems in the prior art, the invention provides the trenchless detection method which can avoid blind excavation, is simple in node and branch numbering method, can improve the diagnosis precision, reduces the detection time consumption, shortens the length of a measurement lead, reduces the error influence of contact resistance on branch resistance inverse operation, and greatly improves the diagnosis precision, and is suitable for the grounding grid of the oil field tank field.
In order to achieve the purpose, the invention provides a trenchless detection method suitable for an oil field tank field grounding grid, wherein the detection method comprises the following steps:
step S1: drawing a topological structure diagram according to a construction diagram of a tank field grounding grid, wherein the topological structure diagram takes a grounding grid down lead as a node and a connecting line of two connected nodes as a branch, and finally forms a topological structure diagram consisting of a plurality of circles and connecting lines between two adjacent circles;
step S2: combining the topological structure chart to carry out node numbering and branch numbering on the tank field grounding grid;
step S3: generating a correlation node matrix according to the node number and the branch number;
step S4: according to the topological structure diagram, a branch between two nodes is electrically connected by an auxiliary lead; then, sequentially measuring the resistance of each branch corresponding to the auxiliary lead, the contact resistance of each auxiliary lead and a down lead port of the grounding grid, and measuring the port resistance between adjacent nodes;
step S5: the corrosion fault detection program utilizes the measured resistance of the auxiliary lead, the contact resistance and the port resistance to calculate a multiple relation between the actual resistance and the resistance under the condition of no corrosion;
step S6: obtaining a corrosion detection result; in a visual display diagram, i.e., a diagnosis schematic diagram, of the corrosion fault detection program, the colors of the ring segments with the corrosion degrees from no corrosion, slight corrosion, medium corrosion to severe corrosion are blue, yellow, orange and red respectively.
Further, in step S2, the method for numbering the tank farm grounding grid branches and nodes includes the following steps:
step S201: taking the circle at the leftmost end of the uppermost side in the topological structure chart as an initial circle, and sequencing other circles in sequence from left to right and from top to bottom;
step S202: selecting a node of the starting circle as a starting point, marking as a node 1, and numbering other nodes of the starting circle along the clockwise direction; similarly, node numbering is carried out on other circles in sequence according to the ordering of the circles, and by analogy, all node numbering is completed; the circles in the same row are subjected to node numbering by taking a node connected with a left side circle of the circle as an initial node of the circle, and the circles in the leftmost column are subjected to node numbering by taking a node connected with an upper side circle of the circle as an initial node of the circle;
step S203: taking the branch with the node No. 1 as the starting point in the starting circle along the clockwise direction as a starting branch, marking as a branch 1, and sequentially numbering the other branches of the starting circle along the clockwise direction; similarly, branch numbering is carried out on other circles in sequence according to the ordering of the circles, and by analogy, node numbering of all circles is completed; then, branch numbering is carried out on the branches between the circles according to the sequence from left to right and from top to bottom, and finally all branch numbering is finished; the minimum branch number of each circle corresponds to a branch which takes the minimum node number of the circle as a starting point in the clockwise direction.
Further, in step S3, the method for generating the correlation node matrix includes the following steps:
step S301: constructing a matrix by taking branch numbers as horizontal and node numbers as vertical, wherein the matrixes are sequentially increased from 1 in the horizontal and vertical directions; according to the clockwise direction, if the branch n flows into the node m, the elements of the nth row and the mth line are-1, if the branch n flows out of the node k, the elements of the nth row and the kth line are 1, and the rest elements are zero, so that an initial correlation node matrix is generated;
step S302: and selecting the node with the last node number as a reference node, deleting the row corresponding to the reference node in the initial associated node matrix, and generating the final associated node matrix.
Further, in step S5 and step S7, the calculation method of the corrosion fault detection program specifically includes: firstly, establishing mathematical equations before and after corrosion of a grounding grid conductor by utilizing the Taylor's theorem and a circuit principle;
secondly, the numerical value of the contact resistance is used as error correction, and a contact resistance error correction equation is established;
and finally, carrying out numerical value iterative calculation by using a non-negative least square method to obtain a final calculation result, namely a multiple relation between the actual resistance and the resistance without corrosion, and displaying the final calculation result in a visual display graph, namely the diagnosis schematic diagram.
The corrosion fault detection program mainly treats the tank area grounding grid conductor as a pure resistance network through a corrosion fault parameter identification method, establishes mathematical equations before and after the grounding grid conductor is corroded by utilizing the Taylor's theorem and a circuit principle, and performs numerical iterative operation by utilizing a least square method so as to obtain the increase multiple of the branch resistance. The horizontal voltage-sharing conductors of the underground grounding grid are connected with each other to form a circuit network, and the grounding grid can be regarded as a pure resistance network by neglecting the influence of soil factors. After the construction of the tank area grounding grid is completed, because parameters such as the length, the sectional area and the resistivity of materials of each section of conductor are determined, the corresponding resistance value of each section of conductor can be obtained by ohm's law, and the value is a constant value under the condition of neglecting the change of ambient temperature, and is called as a design value or a nominal value; when a certain section of conductor in the grounding grid is broken or corroded, the conductivity of the conductor is reduced, and the resistance is increased, and the value is called as an actual value. The oil storage tanks in the tank area are all provided with grounding grid down leads connected with the grounding grid, nodes corresponding to the grounding grid down leads are reachable nodes, port resistance among the nodes can be measured by adopting a digital direct current bridge, a proper calculation method is applied, so that the actual resistance value of each section of conductor of the grounding grid is calculated and compared with a design value, the multiple of increase of branch resistance is obtained, and whether the conductors of the grounding grid are corroded or not, and the corrosion positions and the corrosion severity of the conductors of the grounding grid can be judged. If the resistance value of the conductor at a certain position of the grounding grid is obviously higher than a normal value, the conductor at the position is broken or corroded.
For a circuit with n +1 nodes and b branches, two expressions of the Taylor's theorem are used, namely:
wherein, UkVoltage representing branch k, IkCurrent, U, representing branch kkIkRepresenting the electrical power of branch k. N and N 'are circuits with the same topological structure, corresponding branches and nodes have the same number, the reference directions of the corresponding branches are the same, and I'K、U′kBranch current and branch voltage, I, of the electrical network N', respectivelyk、UkRespectively the branch current and the branch voltage of the electrical network N.
By deriving the values by the circuit principle using expressions (1) to (3), the following relational expression between the variation of the branch resistance and the variation of the port resistance can be obtained
Wherein Δ RijThe change in port resistance for ij from the normal case, Δ RkIs the change in resistance of branch k from normal, IkFor corrosion of the current of the branch k before the fault, Ik' is the current of branch k after corrosion failure, I0The magnitude of the current applied between the ij ports. The variable number of the resistance of the branch is b, which can be found by the equation (4), and in order to improve the accuracy of iterative computation convergence, the number of the equations needs to be increased by measuring the number of the resistance of more ports. Considering that a tank field grounding network is usually an annular grounding network, one node is usually directly connected with two branches, and the constraint conditions of the branches and the nodes are few, a measurement port needs to be reasonably selected, and a large number of field tests and simulation tests are carried out to summarize the adjacent node measurement scheme. Obtaining a relational equation of the port resistance and the branch resistance of the formula (5):
in addition, the arithmetic mean of the contact resistances is obtained from the previously obtained standardized measurement scheme of the contact resistances
This value is added as an error correction to equation (5), to obtain a contact resistance error correction equation of equation (6):
where m is the number of ports measured, IkCan be prepared from RkThus obtaining the product. And l'kFrom R'kR 'is determined'kUnknown, so the equations cannot be solved yet at this time. To solve the problem, introduce non-negative-mostAn iterative method of small two multiplications. As shown in formula (7):
first, let I'k(0)＝IkThe equation set becomes a linear equation set, but the equation set m is less than the equation set b, and the non-negative least square method optimization algorithm of the formula (7) is used for solving the delta Rk(0) And R'k(0) Followed by R'k(0) Calculating l'k(1) (ii) a Then from l'k(1) Calculating R'k(1). And repeating the above calculation until the obtained resistance increment meets the requirement to obtain the final calculation result.
Further, since the wires of the digital dc bridge are usually short, and the port distance of the tank field grounding grid is usually more than ten meters, an auxiliary wire is required to be connected to the digital dc bridge to extend the measurement radius. Because the digital direct current bridge adopts a four-wire method to measure the resistance, the influence of the contact resistance can be effectively eliminated, and the influence of the contact resistance only exists between the auxiliary lead and the down lead port. In step S4, the method for measuring the contact resistance between the auxiliary conductor and the down lead port of the grounding grid includes the following steps:
step 401: firstly, smoothing the outer surface of the grounding grid down lead of the measuring port by using a grinding tool until a coating is completely removed;
step 402: respectively clamping the smooth parts of the auxiliary lead and the grounding grid down lead by using rotary steel plate tongs, rotating the rotary steel plate tongs, and continuing to rotate for a circle and a half when the grounding grid down lead is just in contact with the auxiliary lead, so as to ensure that the rotary steel plate tongs can completely clamp the auxiliary lead and the grounding grid down lead;
step 403: measuring the resistance between two points of the auxiliary lead close to the joint and the grounding grid downlead close to the joint by using a direct current bridge, wherein the value is the contact resistance value between the auxiliary lead and the downlead conductor connected by the rotary steel plate tongs;
step 404: repeating the steps one to three for a plurality of times, and taking the arithmetic average value, wherein the numerical value is the contact resistance.
The contact resistance standardization measurement step is used for measuring the contact resistance under a certain connecting tool, and the numerical value of the contact resistance is input into a zero setting compensation module of a corrosion fault detection program.
Further, in step 402, the position where the rotary steel plate tongs clamp the grounding grid down lead is arranged at a position 1cm-5cm away from the edge of the port of the grounding grid down lead, so that the conductor can be conveniently screwed, and the polishing treatment process of the grounding grid down lead can be conveniently carried out.
Further, in the step 4, the port resistances between all the adjacent nodes are measured, and when the port resistances between the adjacent nodes are measured, two nodes respectively adjacent to the reference node are used as the adjacent nodes, so that the number of equations is increased, and the accuracy of iterative computation is improved.
Furthermore, the number of the auxiliary wires is two, the length of each auxiliary wire is 10m-15m, considering that the tank field grounding grid is not large, the measurement port is an adjacent node, and the distance between the adjacent nodes is usually about 10m, so that the length of the auxiliary wires is 10m-15m, the measurement distance requirement of the adjacent nodes can be met, and meanwhile, the auxiliary wires are not too long, and the complexity of wire arrangement is avoided.
The invention has the beneficial effects that: 1) the measuring method can effectively realize the trenchless detection of the corrosion fault of the grounding grid in the tank area, avoid the blind excavation and reduce the manpower, material resources and financial resources; 2) the numbering method of the nodes and the branches is simple, the method is suitable for the tank field annular grounding network, and the corrosion fault diagnosis precision of the tank field grounding network can be improved; 3) the total time consumption of corrosion fault detection is effectively reduced, only one measurement and calculation are needed, repeated measurement and repeated calculation are not needed, and the measurement time consumption is greatly reduced; 4) the length of a port resistance measuring lead is shortened, the wiring workload is reduced, and the measuring time is saved; 5) the influence of the contact resistance on the error of the branch resistance inverse operation is reduced, and the diagnosis precision is greatly improved.
Drawings
FIG. 1 is a flow chart of the detection method of the present invention.
FIG. 2 is a schematic diagram of a numbering method of branches and nodes of the grounding grid topological structure of the oilfield tank field.
Fig. 3 is a corresponding associated node matrix diagram of fig. 2.
FIG. 4 is a schematic diagram of a port resistance detection arrangement according to the present invention.
FIG. 5 is a schematic diagram of the detection method of the present invention.
Wherein the reference numerals are: 1. an auxiliary wire; 2. rotary steel plate tongs; 3. and a down lead of the grounding grid.
Detailed Description
In order to clearly illustrate the technical features of the present solution, the present solution is explained below by way of specific embodiments.
Referring to fig. 1 to 5, an embodiment of the present invention provides a trenchless detection method suitable for an oil field tank field grounding grid, where the detection method includes the following steps:
step S1: drawing a topological structure diagram according to a construction diagram of a tank field grounding grid, wherein the topological structure diagram takes a grounding grid down lead as a node, and a connecting line of two connected nodes as a branch, and finally forms a topological structure diagram consisting of a plurality of circles and connecting lines between two adjacent circles;
step S2: combining the topological structure chart to carry out node numbering and branch numbering on the tank field grounding grid;
step S3: generating a correlation node matrix according to the node number and the branch number;
step S4: according to the topological structure diagram, a branch between two nodes is electrically connected by an auxiliary lead; then, sequentially measuring the resistance of each branch corresponding to the auxiliary lead, the contact resistance of each auxiliary lead and a down lead port of the grounding grid, and measuring the port resistance between adjacent nodes;
step S5: the corrosion fault detection program utilizes the measured resistance, contact resistance and port resistance of the auxiliary lead to calculate the multiple relation between the actual resistance and the resistance when the auxiliary lead is not corroded;
step S6: obtaining a corrosion detection result; in a visual display of the corrosion failure detection program, i.e., a diagnostic schematic, the ring segments, which have levels of corrosion from no corrosion, slight corrosion, moderate corrosion to severe corrosion, are blue, yellow, orange, and red in color, respectively.
Further, in step S2, the method for numbering the branches and nodes of the tank farm grounding network includes the following steps:
step S201: taking the circle at the leftmost end of the uppermost side in the topological structure chart as an initial circle, and sequencing other circles in sequence from left to right and from top to bottom;
step S202: selecting a node of the starting circle as a starting point, marking as a node 1, and numbering other nodes of the starting circle along the clockwise direction; similarly, node numbering is carried out on other circles in sequence according to the ordering of the circles, and by analogy, all node numbering is completed; the circles in the same row are subjected to node numbering by taking a node connected with a left side circle of the circle as an initial node of the circle, and the circles in the leftmost column are subjected to node numbering by taking a node connected with an upper side circle of the circle as an initial node of the circle;
step S203: taking a branch with the node No. 1 as a starting point in the starting circle in the clockwise direction as a starting branch, marking as a branch 1, and sequentially numbering the other branches of the starting circle in the clockwise direction; similarly, branch numbering is carried out on other circles in sequence according to the ordering of the circles, and by analogy, node numbering of all circles is completed; then, branch numbering is carried out on the branches between the circles according to the sequence from left to right and from top to bottom, and finally all branch numbering is finished; the minimum branch number of each circle corresponds to a branch which takes the minimum node number of the circle as a starting point in the clockwise direction.
Further, in step S3, the method for generating the correlation node matrix includes the following steps:
step S301: constructing a matrix by taking branch numbers as horizontal and node numbers as vertical, wherein the matrixes are sequentially increased from 1 in the horizontal and vertical directions; according to the clockwise direction, if the branch n flows into the node m, the elements of the nth row and the mth line are-1, if the branch n flows out of the node k, the elements of the nth row and the kth line are 1, and the rest elements are zero, so that an initial correlation node matrix is generated;
step S302: and selecting the node with the last node number as a reference node, deleting the row corresponding to the reference node in the initial associated node matrix, and generating a final associated node matrix.
Further, in step S5 and step S7, the calculation method of the corrosion failure detection program specifically includes:
firstly, establishing mathematical equations before and after corrosion of a grounding grid conductor by utilizing the Taylor's theorem and a circuit principle;
secondly, the numerical value of the contact resistance is used as error correction, and a contact resistance error correction equation is established:
wherein, Δ RijThe port resistance of ij varies from the normal case,
to contact resistance value, Δ RkIs the change in resistance of branch k from normal, IkFor corrosion of the current of the branch k before the fault, Ik' is the current of branch k after corrosion failure, I0The magnitude of the current applied between the ij ports;
and finally, carrying out numerical value iterative calculation by using a non-negative least square method to obtain a final calculation result, namely a multiple relation between the actual resistance and the resistance without corrosion, and displaying the result in a visual display mode, namely a diagnosis schematic diagram.
Further, in step S4, the method for measuring the contact resistance between the auxiliary conductor 1 and the port of the down conductor 3 of the grounding grid includes the following steps:
step S401: firstly, the outer surface of a grounding grid down lead 3 of a measuring port is smoothened by a grinding tool until a coating is completely removed;
step S402: respectively clamping the smooth parts of the auxiliary lead 1 and the grounding grid down lead 3 by using rotary steel plate tongs 2, rotating the rotary steel plate tongs 2, and continuing to rotate for a circle and a half when the grounding grid down lead 3 is just in contact with the auxiliary lead 1, so as to ensure that the rotary steel plate tongs can completely clamp the auxiliary lead 1 and the grounding grid down lead 3;
step S403: measuring the resistance between two points at the position of the auxiliary lead 1 close to the joint and the position of the grounding grid down lead 3 close to the joint by using a direct current bridge, wherein the value is the contact resistance value between the auxiliary lead and the down lead conductor under the connection of the rotary steel plate tongs;
step S404: and (3) repeating the step one to the step three for a plurality of times, preferably repeating the step one to the step three for ten times, namely obtaining the measured values of ten groups of contact resistors, and taking the arithmetic average value of the measured values, wherein the numerical value is the contact resistance value obtained by the standardized measurement step.
Further, in step 402, the position where the rotary steel plate tongs 2 clamp the grounding grid down lead 3 is arranged at a position 1cm-5cm away from the edge of the port of the grounding grid down lead 3, so that the conductor can be conveniently screwed, and the polishing treatment process of the grounding grid down lead can be conveniently carried out.
Further, in step 4, the port resistances between all adjacent nodes are measured, so that the number of equations is increased, the accuracy of iterative computation is improved, and two nodes respectively adjacent to the reference node are used as adjacent nodes when the port resistances between the adjacent nodes are measured.
Furthermore, the number of the auxiliary wires 1 is two, the length of each auxiliary wire 1 is set to be 10m-15m, considering that the tank field grounding grid is not large, the measurement port is an adjacent node, and the distance between the adjacent nodes is usually about 10m, so that the length of the auxiliary wire is set to be 10m-15m, the measurement distance requirement of the adjacent nodes can be met, and meanwhile, the auxiliary wire is not too long, and the wire arrangement is complicated.
Experimental example 1:
step S1: drawing a topological structure diagram according to a construction diagram of a tank field grounding grid, wherein the topological structure diagram takes a grounding grid down lead as a node, and a connecting line of two connected nodes as a branch, and finally forms a topological structure diagram consisting of a plurality of circles and connecting lines between two adjacent circles;
step S2: node numbering 1, 2, 3 and 4 and branch numbering 1, 2, 3 and 4 are carried out by combining the topological structure diagram and utilizing a method for numbering the branches and the nodes of the tank area grounding network;
step S3: generating a correlation node matrix according to the node number and the branch number;
step S4: according to the topological structure diagram, two auxiliary wires which are about 10m long are used for electrically connecting branches between two nodes; then, measuring the resistance of the auxiliary lead 1 by using a digital direct current bridge, wherein the total resistance value is 36.52m omega, measuring ten groups of numerical values of contact resistances of each auxiliary lead and a down lead port of the grounding network by using a contact resistance standardized measurement method, the arithmetic mean value of the numerical values is 3.56m omega, and measuring the port resistance between adjacent nodes;
step S5: the corrosion fault detection program calculates the multiple relation between the actual resistance and the resistance under the non-corrosion condition by using the measured resistance, contact resistance and port resistance of the auxiliary lead, wherein the multiple of the increase of the port resistance with branch numbers of 1, 2 and 3 is 0.12, 0.33 and 0.04, and the multiple of the increase of the port resistance with branch number of 4 is 1.87;
step S6: obtaining a corrosion detection result; in the visual display of the corrosion fault detection program, namely the diagnosis schematic diagram, the color of the ring segments with the branch numbers 1, 2 and 3 is blue, and the color of the ring segment with the branch number 4 is orange.
In addition, the grounding grid conductor with the branch number of 4 is excavated, and the grounding grid conductors with the branch numbers of 1, 2 and 3 are observed to be almost free from corrosion, and the grounding grid conductor with the branch number of 4 is obviously corroded, so that the accuracy of the detection procedure is verified.
Experimental example 2:
step S1: drawing a topological structure diagram according to a construction diagram of a tank field grounding grid, wherein the topological structure diagram takes a grounding grid down lead as a node, and a connecting line of two connected nodes as a branch, and finally forms a topological structure diagram consisting of a plurality of circles and connecting lines between two adjacent circles;
step S2: node numbering and branch numbering are carried out by combining the topology structure diagram and utilizing a method for numbering the tank field grounding grid branches and nodes;
step S3: generating a correlation node matrix according to the node number and the branch number;
step S4: according to the topological structure diagram, two auxiliary wires which are about 10m long are used for electrically connecting branches between two nodes; then, measuring the resistance of the auxiliary lead 1 by using a digital direct current bridge, wherein the total resistance value is 33.48m omega, measuring ten groups of numerical values of contact resistances of each auxiliary lead and a down lead port of the grounding network by using a contact resistance standardized measurement method, the arithmetic mean value of the numerical values is 3.18m omega, and measuring the port resistance between adjacent nodes;
step S5: the corrosion fault detection program calculates the multiple relation between the actual resistance and the resistance under the non-corrosion condition by using the measured resistance, contact resistance and port resistance of the auxiliary lead, wherein the port resistance increasing multiples with branch numbers of 1, 2 and 3 are 0.22, 0.30 and 0.14, and the port resistance increasing multiple with branch number of 4 is 2.17;
step S6: obtaining a corrosion detection result; in the visual display of the corrosion fault detection program, namely the diagnosis schematic diagram, the color of the ring segments with the branch numbers 1, 2 and 3 is blue, and the color of the ring segment with the branch number 4 is orange.
In addition, the grounding grid conductor with the branch number of 4 is excavated, and the grounding grid conductors with the branch numbers of 1, 2 and 3 are observed to be almost free from corrosion, and the grounding grid conductor with the branch number of 4 is obviously corroded, so that the accuracy of the detection procedure is verified.
Dozens of grounding grids in the victory oil field are subjected to corrosion detection by the detection method, and the accuracy is 95% through verification of an excavation mode.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.
Claims (8)
1. The trenchless detection method suitable for the grounding grid of the oil field tank field is characterized by comprising the following steps:
step S1: drawing a topological structure diagram according to a construction diagram of a tank field grounding grid, wherein the topological structure diagram takes a grounding grid down lead as a node and a connecting line of two connected nodes as a branch, and finally forms a topological structure diagram consisting of a plurality of circles and connecting lines between two adjacent circles;
step S2: combining the topological structure chart to carry out node numbering and branch numbering on the tank field grounding grid;
step S3: generating a correlation node matrix according to the node number and the branch number;
step S4: according to the topological structure diagram, a branch between two nodes is electrically connected by an auxiliary lead; then, sequentially measuring the resistance of each branch corresponding to the auxiliary lead, the contact resistance of each auxiliary lead and a down lead port of the grounding grid, and measuring the port resistance between adjacent nodes;
step S5: the corrosion fault detection program utilizes the measured resistance of the auxiliary lead, the contact resistance and the port resistance to calculate a multiple relation between the actual resistance and the resistance under the condition of no corrosion;
step S6: obtaining a corrosion detection result; in a visual display diagram, i.e., a diagnosis schematic diagram, of the corrosion fault detection program, the colors of the ring segments with the corrosion degrees from no corrosion, slight corrosion, medium corrosion to severe corrosion are blue, yellow, orange and red respectively.
2. The trenchless detection method of claim 1 wherein the step S2 of numbering the tank field grounding grid branches and nodes comprises the steps of:
step S201: taking the circle at the leftmost end of the uppermost side in the topological structure chart as an initial circle, and sequencing other circles in sequence from left to right and from top to bottom;
step S202: selecting a node of the starting circle as a starting point, marking as a node 1, and numbering other nodes of the starting circle along the clockwise direction; similarly, node numbering is carried out on other circles in sequence according to the ordering of the circles, and by analogy, all node numbering is completed; the circles in the same row are subjected to node numbering by taking a node connected with a left side circle of the circle as an initial node of the circle, and the circles in the leftmost column are subjected to node numbering by taking a node connected with an upper side circle of the circle as an initial node of the circle;
step S203: taking the branch with the node No. 1 as the starting point in the starting circle along the clockwise direction as a starting branch, marking as a branch 1, and sequentially numbering the other branches of the starting circle along the clockwise direction; similarly, branch numbering is carried out on other circles in sequence according to the ordering of the circles, and by analogy, node numbering of all circles is completed; then, branch numbering is carried out on the branches between the circles according to the sequence from left to right and from top to bottom, and finally all branch numbering is finished; the minimum branch number of each circle corresponds to a branch which takes the minimum node number of the circle as a starting point in the clockwise direction.
3. The trenchless detection method for the grounding grid of the oilfield tank field according to claim 1 or 2, wherein the method for generating the correlation node matrix in the step S3 comprises the following steps:
step S301: constructing a matrix by taking branch numbers as horizontal and node numbers as vertical, wherein the matrixes are sequentially increased from 1 in the horizontal and vertical directions; according to the clockwise direction, if the branch n flows into the node m, the elements of the nth row and the mth line are-1, if the branch n flows out of the node k, the elements of the nth row and the kth line are 1, and the rest elements are zero, so that an initial correlation node matrix is generated;
step S302: and selecting the node with the last node number as a reference node, deleting the row corresponding to the reference node in the initial associated node matrix, and generating the final associated node matrix.
4. The trenchless detection method for the grounding grid of the oilfield tank field according to any one of claims 1 to 3, wherein the calculation method of the corrosion failure detection program in the steps S5 and S7 is specifically as follows:
firstly, establishing mathematical equations before and after corrosion of a grounding grid conductor by utilizing the Taylor's theorem and a circuit principle;
secondly, the numerical value of the contact resistance is used as error correction, and a contact resistance error correction equation is established:
wherein, Δ RijThe port resistance of ij varies from the normal case,
the contact being the contact resistance, Δ RkIs the change in resistance of branch k from normal, IkFor corrosion of the current of the branch k before the fault, Ik' is the current of branch k after corrosion failure, I0The magnitude of the current applied between the ij ports;
and finally, carrying out numerical value iterative calculation by using a non-negative least square method to obtain a final calculation result, namely a multiple relation between the actual resistance and the resistance without corrosion, and simultaneously displaying the diagnosis schematic diagram.
5. The trenchless detection method for the ground grid of the oilfield tank field according to any one of claims 1 to 4, wherein the step S4 of measuring the contact resistance of the auxiliary conductor (1) and the port of the down conductor (3) of the ground grid comprises the following steps:
step 401: firstly, the surface of the grounding grid down lead (3) of the measuring port is smoothed by a grinding tool until the coating is completely removed;
step 402: respectively clamping the smooth parts of the auxiliary lead (1) and the grounding grid down lead (3) by using rotary steel plate tongs (2), rotating the rotary steel plate tongs (2), and continuing to rotate for a circle and a half when the grounding grid down lead (3) is just in contact with the auxiliary lead (1) so as to ensure that the rotary steel plate tongs can completely clamp the auxiliary lead (1) and the grounding grid down lead (3);
step 403: measuring the resistance between two points of the auxiliary lead (1) close to the joint and the grounding grid down lead (3) close to the joint by using a direct current bridge, wherein the value is the contact resistance value between the auxiliary lead and the down lead conductor connected by the rotary steel plate tongs;
step 404: and repeating the step one to the step three for a plurality of times, and taking the arithmetic mean value of the arithmetic mean value, wherein the numerical value is the contact resistance obtained by the standardized measurement step.
6. The trenchless detection method of the ground net suitable for the oilfield tank field according to claim 5, wherein in the step 402, the position where the rotary steel plate tongs (2) clamp the ground net down-lead (3) is arranged at a distance of 1cm-5cm from the port edge of the ground net down-lead (3).
7. The trenchless detection method of any of claims 1 to 6 wherein in step 4, the port resistance between all adjacent nodes is measured, and when the port resistance between adjacent nodes is measured at the reference node position, two nodes respectively adjacent to the reference node are used as adjacent nodes.
8. The trenchless detection method for the grounding grid of the oilfield tank field according to any one of claims 1 to 7, wherein the number of the auxiliary conductors (1) is set to two, and the length of each of the auxiliary conductors (1) is set to 10m to 15 m.
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Citations (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| 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 |
| US7340703B2 (en) * | 2004-08-02 | 2008-03-04 | Hazem Mahmoud Hegazy | Test structures and method for interconnect impedance property extraction |
| CN101493491A (en) * | 2009-02-16 | 2009-07-29 | 陕西电力科学研究院 | Substation ground network defect synthesis diagnosis method and diagnosis system thereof |
| CN102096744A (en) * | 2011-03-07 | 2011-06-15 | 杭州电子科技大学 | Irregular iteration parallelization method |
| CN102646213A (en) * | 2012-02-24 | 2012-08-22 | 上海交通大学 | Detecting method of corrosion diagnosis system of grounding grid based on chaos particle swarm algorithm |
| CN202453451U (en) * | 2012-02-03 | 2012-09-26 | 重庆市电力公司电力科学研究院 | Earth grid corrosion and broken point diagnosing system for large and medium-sized substations |
| CN102707191A (en) * | 2012-04-24 | 2012-10-03 | 广东电网公司电力科学研究院 | Diagnosis device and diagnosis method for corrosion of earth screen of large-size transformer substation |
| CN102809714A (en) * | 2012-08-02 | 2012-12-05 | 兰州交通大学 | Method for diagnosing corrosion fault of grounding grid of traction substation |
| CN103135137A (en) * | 2013-03-13 | 2013-06-05 | 重庆大学 | Grounding grid topological structure detection method based on differential method |
| CN103605042A (en) * | 2013-08-27 | 2014-02-26 | 上海交通大学 | Ground grid fault diagnosis method based on self-adaptive particle swarm algorithm |
| CN104142455A (en) * | 2014-08-20 | 2014-11-12 | 国家电网公司 | Grounding grid corrosion fault diagnosis method based on Tellegen theorem |
| CN104865487A (en) * | 2014-08-20 | 2015-08-26 | 上海交通大学 | Sub-area fault diagnosis method for transformer station grounding network |
| CN104897995A (en) * | 2015-06-10 | 2015-09-09 | 国网上海市电力公司 | Transformer station grounding network corrosion detecting system based on earth surface potential, and method thereof |
| CN105652155A (en) * | 2016-03-03 | 2016-06-08 | 国网山东省电力公司章丘市供电公司 | Transformer substation grounding grid fault corrosion monitoring method and system |
| CN106353618A (en) * | 2016-09-08 | 2017-01-25 | 西安工程大学 | Grounding state comprehensive monitoring device and monitoring method for grounding grid |
-
2019
- 2019-04-18 CN CN201910315089.3A patent/CN111830362B/en active Active
Patent Citations (16)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| 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 |
| US7340703B2 (en) * | 2004-08-02 | 2008-03-04 | Hazem Mahmoud Hegazy | Test structures and method for interconnect impedance property extraction |
| CN101493491A (en) * | 2009-02-16 | 2009-07-29 | 陕西电力科学研究院 | Substation ground network defect synthesis diagnosis method and diagnosis system thereof |
| CN102096744A (en) * | 2011-03-07 | 2011-06-15 | 杭州电子科技大学 | Irregular iteration parallelization method |
| CN202453451U (en) * | 2012-02-03 | 2012-09-26 | 重庆市电力公司电力科学研究院 | Earth grid corrosion and broken point diagnosing system for large and medium-sized substations |
| CN102646213A (en) * | 2012-02-24 | 2012-08-22 | 上海交通大学 | Detecting method of corrosion diagnosis system of grounding grid based on chaos particle swarm algorithm |
| CN102707191A (en) * | 2012-04-24 | 2012-10-03 | 广东电网公司电力科学研究院 | Diagnosis device and diagnosis method for corrosion of earth screen of large-size transformer substation |
| CN102809714A (en) * | 2012-08-02 | 2012-12-05 | 兰州交通大学 | Method for diagnosing corrosion fault of grounding grid of traction substation |
| CN103135137A (en) * | 2013-03-13 | 2013-06-05 | 重庆大学 | Grounding grid topological structure detection method based on differential method |
| CN103605042A (en) * | 2013-08-27 | 2014-02-26 | 上海交通大学 | Ground grid fault diagnosis method based on self-adaptive particle swarm algorithm |
| CN104142455A (en) * | 2014-08-20 | 2014-11-12 | 国家电网公司 | Grounding grid corrosion fault diagnosis method based on Tellegen theorem |
| CN104865487A (en) * | 2014-08-20 | 2015-08-26 | 上海交通大学 | Sub-area fault diagnosis method for transformer station grounding network |
| CN105044559A (en) * | 2014-08-20 | 2015-11-11 | 上海交通大学 | Transformer station grounding grid partitional fault diagnosis method |
| CN104897995A (en) * | 2015-06-10 | 2015-09-09 | 国网上海市电力公司 | Transformer station grounding network corrosion detecting system based on earth surface potential, and method thereof |
| CN105652155A (en) * | 2016-03-03 | 2016-06-08 | 国网山东省电力公司章丘市供电公司 | Transformer substation grounding grid fault corrosion monitoring method and system |
| CN106353618A (en) * | 2016-09-08 | 2017-01-25 | 西安工程大学 | Grounding state comprehensive monitoring device and monitoring method for grounding grid |
Non-Patent Citations (2)
| Title |
|---|
| TAO ZHANG 等: "Research on fault diagnosis of grounding girds based on intelligence hybrid method", 《2014 INTERNATIONAL CONFERENCE ON LIGHTNING PROTECTION (ICLP)》 * |
| 刘洋 等: "基于电磁感应原理的变电站接地网腐蚀诊断方法", 《中国电机工程学报》 * |
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