KR100657855B1 - A method for detecting grounded network erosion and broken point of substation - Google Patents

A method for detecting grounded network erosion and broken point of substation Download PDF

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KR100657855B1
KR100657855B1 KR1020050123788A KR20050123788A KR100657855B1 KR 100657855 B1 KR100657855 B1 KR 100657855B1 KR 1020050123788 A KR1020050123788 A KR 1020050123788A KR 20050123788 A KR20050123788 A KR 20050123788A KR 100657855 B1 KR100657855 B1 KR 100657855B1
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ground
ground wire
resistance
wire network
network
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Korean (ko)
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황영식
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벽산엔지니어링주식회사
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    • GPHYSICS
    • G01MEASURING; TESTING
    • G01RMEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/08Locating faults in cables, transmission lines, or networks
    • G01R31/081Locating faults in cables, transmission lines, or networks according to type of conductors
    • G01R31/083Locating faults in cables, transmission lines, or networks according to type of conductors in cables, e.g. underground
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01RMEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R27/00Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
    • G01R27/02Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
    • G01R27/16Measuring impedance of element or network through which a current is passing from another source, e.g. cable, power line
    • G01R27/18Measuring resistance to earth, i.e. line to ground
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01RMEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/08Locating faults in cables, transmission lines, or networks
    • G01R31/088Aspects of digital computing

Abstract

The present invention provides a method for identifying a corrosion and disconnection point of a substation ground wire network, the method comprising: 1) connecting between two ground wires of a ground wire network using a DC power source and applying a large DC current to the ground wire network; 2) Measuring the voltage between the two ground leads and the current in the circuit to obtain the input resistance or transition resistance between the two ground leads, and 3) all according to the requirements of the measurement scheme determined by the phase structure of the ground wire network and all ground lead positions. 4) measuring the input resistance and the transition resistance between the ground leads, and 4) inputting the measurement result and the phase structure of the ground wire network into the diagnostic software, the diagnostic software analyzes and obtains the resistance value of the conductors of each part The resistance value of the ground wire conductor in the part is compared with the design resistance value obtained by calculation and analysis when the ground wire network is intact. And determining whether or not the conductor of the ground wire network is disconnected and a corrosion state.

Description

A method for detecting grounded network erosion and broken point of substation

1 is a ground wire network diagram.

2 is a diagram of a measuring method of the present invention.

3 is a diagram of a network before and after failure. 3A is a network before failure and FIG. 3B is a network after failure.

4 is a flowchart of a calculation module of the present invention.

5 is a structural diagram of a measurement system of the present invention.
Fig. 6 is a software flowchart of the measuring device single chip computer of this embodiment.

7 is a partial structural diagram of a ground wire network according to an embodiment of the present invention.

8 is a result of grasping the embodiment of the present invention.

9 is a calculation resistance increase multiple of each branch circuit of the embodiment of the present invention.

Explanation of symbols for the main parts of the drawings

11: ground wire network 13: ground lead

21: DC power supply 22: measuring system

101: collection port 102: collection port

The present invention belongs to the area of precision measurement and analysis of electric quantity, and especially accurate and reliable identification of failures such as corrosion and disconnection points of substation ground network and failure of welding and failure of new ground wire network in the normal operation of power system. It is about a method. It can also be used to identify corrosion of metal pipes (water pipes, gas pipes, oil pipes).

In the substation, a large amount of important electrical equipment is concentrated, so a good grounding device must satisfy the requirements of working ground, safety ground and lightning protection ground. The grounding device used in the process is a grounding net and is a net 11 made by welding with a flat steel sheet, a circular steel sheet, an L-shaped steel or a steel pipe. The ground lead 13 is connected to the node of this network as shown in FIG. This network is buried at a certain depth underground and serves to reduce voltage equality, current distribution and ground resistance. Expose one end of the ground lead to the ground and connect it to the utility.

In the event of a short-circuit at the substation, the fault current I enters the ground through the ground network. The smaller the ground resistance R, the lower the potential rise U of the ground network. At this time, the potential of the grounded object on the ground is also relatively low to ensure safety. The substation's ground wire network is an important measure to safeguard the power system and ensure the safety of the personnel. The conductors constituting the grounding network are buried underground and are always grounded due to corrosion of the grounding wire conductors and grounding conductors due to poor welding during welding, leakage of soil, soil corrosion, and action of ground short-circuit current power. This leads to poor electrical connection performance and higher ground resistance. If the electrical system has a ground short fault, not only the potential difference between the ground wire network itself and the ground wire network potential increase, but also threaten the operation personnel, and the insulation of the secondary equipment is destroyed and the high pressure Passing through the control room leads to malfunctions in the inspection or control equipment, resulting in huge economic losses. In corrosive soils, the annual corrosion rate of ground wire mesh is 2.0 mm and 8.0 mm in extremely corrosive soils. Accidents due to corrosion or disconnection of the ground wire sometimes occur, and each and every accident causes huge direct economic losses.

At present, the means of understanding the point of corrosion or breakage of ground wire networks is very primitive. Commercial methods where power systems currently require ground wire corrosion and disconnection points are power outages and sampling. After a few years, the soil corrosion rate is estimated empirically by the local soil corrosion rate, and then excavated and examined by sampling. This method is blind, heavy and slow. In addition, it is not possible to accurately determine the break point and the degree of corrosion due to the limitations of the field operating conditions. At the same time, since the substation bears huge responsibility for national production, the outage could not avoid huge economic losses, which caused difficulties in actual operation.

However, the method currently adopted for the inspection of the failure of lead wires is to visually observe the corrosion situation of the ground portion of the ground lead by visual inspection of the A / S personnel, and to observe the disconnection of the shallow layer portion below the ground by shaking the ground lead vigorously. . However, the part on the ground conductor surface is always coated with a rust preventive layer, so when using this method, it is impossible to fundamentally determine the degree of corrosion and the degree of corrosion inside the rust preventive layer of the lead. In addition, since most of the ground conductors are steel materials such as flat steel sheets and circular steel sheets, it is impossible to determine whether the conductors of relatively deep conductors are broken even if they are shaken vigorously. Thus, this method is inevitable against corrosion under ground conductors.

An alternative method is to analyze the corrosion conditions of the ground wire network by measuring the ground resistance of the entire ground wire network. This method is problematic in principle. When there is a point of corrosion or breakage of the ground wire, the ground resistance of the ground wire is basically unchanged. That is, even if the ground wire network is severely corroded and the ground wire network is broken, the measured ground resistance after splitting due to the mutual resistance of the two ground wire networks is relatively unchanged. In addition, the ground resistance changes relatively with the seasonal variation of soil resistivity, the measurement method, and the direction of measurement. In other words, the measured ground resistance does not occur due to corrosion or disconnection of the ground wire. In other words, even if the grounding resistance of the grounding wire network can violate the corrosion situation of the grounding wire network, the exact failure site cannot be determined. Inevitably, the artificial sampling should be carried out by digging or inspection to a large extent, which leads to a high cost and a large amount of detection work. The failure of the ground wire network has already made great difficulty in the safe operation of the power system.

The object of the present invention is to overcome the shortcomings of the existing technology and to identify a kind of substation ground wire network corrosion and disconnection point, and its measuring method, and a grading system, so that each part of the ground wire network can be challenged in the situation where the ground wire network is not dug up and not dug up. Checking the corrosion and disconnection of the sieve ensures safe and reliable operation of the power system. It also provides a simple, accurate and unrestricted way of operating conditions.

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A method of determining the corrosion and disconnection points of a substation ground wire network, comprising the steps of: 1) connecting between two ground wires of a ground wire network using a DC power source and applying a large DC current to the ground wire network; Measuring the current in the circuit to obtain an input resistance or transition resistance between the two ground leads, and 3) which input conductor and transition resistance between the ground leads should be measured based on the phase structure of the ground wire network and all ground lead positions. And determining the input resistance and the transition resistance to be measured, and 4) inputting the measurement result and the phase structure of the ground wire network to the diagnostic software, the diagnostic software analyzes and obtains the resistance values of the conductors in each part. The resistance value of the ground wire conductor of each part obtained by analysis is calculated and analyzed when the ground wire network is intact. As compared with a step for determining whether a disconnect condition and corrosion of the conductor of the ground network by that threshold value.

In the second step, the voltage U and the current I are measured at the same time by using the measurement method of obtaining the voltage and the applied current between each conductor through the measurement and sampling / maintaining to obtain the same instantaneous values of the voltage and the current. And obtaining an input resistance and a transition resistance between the two ground leads that need to be measured.

In the present invention, a method of identifying the corrosion and disconnection points of the substation ground wire network is presented. The characteristics are as follows.

1. Connect the two ground leads of the ground wire network with DC power and apply a large DC current to the ground wire network.

2. Measure the voltage between the two ground leads of the ground wire network and the current of the circuit to obtain the input resistance and transition resistance between the two ground leads.

3. Determine the input resistance and transition resistance between ground conductors based on the phase structure of the ground wire network and the position of all ground conductors, and measure the input resistance and transition resistance to be the measurement target.

4. Input the measurement result and the phase structure of the ground wire into the diagnostic software, and the diagnostic software analyzes the resistance value of the conductors in each part. The resistance of the ground wire conductor of each part obtained by analysis is compared with the design resistance value (or analysis of past measurement results) obtained when the ground wire network is intact. The threshold value determines whether or not the conductor of the ground wire network is disconnected and the corrosion situation.

The order of the first step is specifically as follows.

1) Input the phase structure of the ground wire network and the position of the ground lead into the diagnostic software. Preferably, the diagnostic software can determine which ground lead to measure the input resistance or transition resistance based on the input phase structure and ground lead position.

2) Inject a large DC current into the grounding wire and between the two grounding wires necessary for the measurement of the grounding wire.

The sequence of the second step is specifically as follows.

Through the measurement, the voltage between each conductor and the magnitude of applied current are obtained, and the same instantaneous values of voltage and current are obtained by simultaneously measuring the voltage U and current I by using a sampling method. That is, obtain the input resistance and the transition resistance between these two ground leads that need to be measured.

By repeating the above auxiliary steps, it is possible to obtain an input resistance or a transition resistance between all the ground leads to be measured in the measurement scheme.

The present invention also provides a ground wire network corrosion and disconnection point measurement and grasp system using the method of identifying the corrosion and disconnection points of the substation ground wire network, which includes a computer and a preconfigured diagnostic software and diagnostic software stored in the memory of the computer. And a fine resistance measuring device in communication with the. The micro-resistance measuring device includes a simulation input electrical circuit for collecting measurement signals, a multi-channel module switching circuit for converting instantaneous simulation measurements of each sample of each circuit into data amounts, and calculating and processing signals converted to data quantities. Single chip computers and their data electrical circuits. The input circuit is composed of voltage limiting protection and expansion electrical circuit. Multichannel simulated data conversion The electrical circuit consists of a multichannel switch, sampling / maintenance, data volume conversion and simulation value conversion. The electrical circuitry of a single chip computer includes data processing, system restoration and data communication, as well as measurement data analysis and processing software, which is preconfigured and stored in a single chip computer memory. Data communication transmits the survey results to the diagnostic software of the computer. The diagnostic software, organized in advance and stored in computer memory, consists of function modules such as phase structure input, measurement method determination, corrosion and break point analysis, and analysis structure display.

The measuring system can capture detailed electronic screens through the box, and the hardware system separates the simulation circuit and the data electrical circuit, separates the power of the data circuit chip, thickens the ground line and wraps it with the ground line. Take measures to remove the module, use “guard” electrical circuits, etc. In software design, repeat play, control by adding the ability to extend the software time at the main program inlet and program the I / O port. The overall resistance capability was secured by setting the command repetition, command duplication, data wave filtering, and data processing.

The basic principle of the present invention is to calculate the resistance of each partial conductor of the ground wire network by applying a calculation method suitable for the phase structure of the ground wire network by the input resistance or the transition resistance measurement between the ground wire network wires, Check the corresponding degree of corrosion. If the resistance of the conductors in any part of the ground wire network increases significantly, explain that there is a break or corrosion.

The present invention establishes a mathematical method and corroded form of corrosion by electric circuit theory and solves the condition and undefined mathematical method using the second-order planning method of optimization theory. The threshold for determining whether the conductor is disconnected is determined by the artificial neural network method. The small resistance precision measurement device researched and manufactured using the present invention has obtained accurate side integer value, and the measurement device solves the influence of disturbance by using a data wave filtering method. Since the electric resistance of the ground wire network itself is relatively small, in order to ensure the accuracy of the measurement, the ability to prevent interference is increased, and a relatively large DC power is injected into the ground wire network to perform the measurement. Measurement optimization is a study on the selection of automatic measurement method through main factor analysis. If the conductor of any part of the ground wire network breaks or corrodes, the conductor resistance of this part will inevitably increase. In addition, all electrical equipment of substations have a grounding wire associated with the grounding wire network. The earth wire resistivity is much larger than the electric resistivity of the metal conductor of the ground wire net, so the ground wire net is equivalent to one concentrated function net resistance network, and the ground wire of the ground wire net is the node of this network. That is, let me measure it. If the ground wire network is a multi-port electric resistance network with the same end point value and the number of ground wires, the ground wire becomes the connection point of this network. That is, it becomes a measurable point. Thus, the problem of measuring the failure point of the ground line network can be measured by the port characteristics of the multi-port network and converted to the inverse function of the network analysis result. In other words, it switches to the problem of identifying the electric resistance network. Thus, by applying the theoretical analysis method based on the measurement of the electric function between the ground conductors of the ground wire network and the known satellite structure of the ground wire network, the electrical resistance value of each section of the ground wire network is obtained and the disconnection point position of each ground wire network Corrosion of conductors can be determined, and the repair and recovery of ground wire networks can be performed relatively, and the remaining service life of ground wire networks can be estimated.

The description method of the present invention is as shown in FIG. The DC power supply (battery) 21 is connected to the ground wire network 11, and a large DC current (about 20 A) is applied to the ground wire network. A and B are two nodes of the ground wire network ground lead 13. 101 and 101 'are current sampling ports of the measurement system 22. 102 and 102 'are the voltage sampling ports of the measurement system and measure the voltage between two available branch circuits A and B. R is the precision electrical resistance for voltage separation and calculates the current of the measuring circuit through the above voltage measurement. In other words, calculate the measured current injected into the ground wire network. The measuring device employed in this method simultaneously collects multichannel data and simultaneously detects the voltage difference between the ground leads and the voltage drop of the precision electrical resistor to obtain the input resistance between the two ground leads.

The description of the mathematical method of earth corrosion detection employed in the present invention is as follows.

The mathematics of ground line network grasp uses the Telegen theorem to derive the relationship between the transition resistance matrix of the multi-port network and the internal function of the network and directly derive the corresponding form of dimensionality. The ground line network faults in substations are many and complex, with many nodes in the ground line network, large and almost soft. According to the network method, it is possible to calculate the electric resistance value of the conductor in each section of the ground wire network by positioning and setting a number of failures, and to determine the failure of the branch circuit based on the amount of change. will be. Therefore, the problem that must be solved is the unknown problem of the grasp equation (the number of unknowns is smaller than the number of known numbers). In the present invention, the grasp equation according to the network method is adopted and converges until the actual solution is made by the mathematical method of the vagina.

The ground wire mesh N before corrosion shown in FIG. 3A and the ground wire mesh N 'after corrosion shown in FIG. 3B are both the same node, branch circuit and number (breakpoints are considered to be one special form of corrosion), exactly the same reference node Have In other words, they have the same phase structure. 13a, 13b and 13m, 13a ', 13b' and 13m 'are the numbers of the ground lead 13 in the ground wire network. This linear network has n nodes (including available nodes), branch circuits on b lines, and m available nodes. The definition of each code is as follows.

Vb = [Vb1, Bb2, ..., Vbb] is a branch circuit voltage direction vector.

Ib = [ib1, ib2, ..., ibb] is the branch circuit current direction vector.

If any branch circuit resistance in the network changes from Rk to Rk ',

Figure 112005073388200-pat00001
(One)

Thus, network N changes to network N 'and the resistance between its I port and j port also changes from Rij to Rij' as follows.

Figure 112005073388200-pat00002
(2)

By Telegen's power theorem,

Figure 112005073388200-pat00003
And
Figure 112005073388200-pat00004
(3)

Where Vk and Vk 'are the voltages for the branch circuits before and after corrosion and Ik and Ik' are the voltages for the branch circuits before and after corrosion. When setting the measurand, the current injected into the ground wire network is Io.

Figure 112005073388200-pat00005
(4)

In addition, Iij = Iij '= Io, which is as follows.

Figure 112005073388200-pat00006
(5)

Figure 112005073388200-pat00007
(6)

When formula (1), formula (4) and formula (5) are replaced with formula (6),

Figure 112005073388200-pat00008

                                                             (7)

After simplifying this, we get

Figure 112005073388200-pat00009
(8)

As a result, an equation in which resistance is measured can be obtained as follows.

Figure 112005073388200-pat00010
(9)

The mathematical relationship between the conductor resistance values of each section of the ground wire network and the electrical function of the ground wire network is a nonlinear relationship. In general, the independent data of the electrical function between the measured ground leads is less than the number of conductors in the ground wire network. Thus, we must consider the problem of solving the undefined nonlinear equations. The change in the electrical function value between the conductors caused by the change in the conductor resistance in each section of the ground wire network is not so obvious that the calculation results are very sensitive to the measurement error. In theory, this is a serious condition problem and must be overcome in some way to reduce the sensitivity of the calculation results to measurement errors. In addition, since measurement values always have specific problems such as errors, it is essential to establish a calculation method that overcomes the effects of matrix pathologies.

The present invention is solved using the optimization method in the present invention, and here, the quadratic programming method is explored to satisfy the optimization solution with certain constraints. Through comparison of various mathematical planning methods, the present invention employs the Richardson method of the second plan calculation method. In order to correct errors in all equations at the same time, the simplest SIRT (Simultaneous Iterative Reconstruction Techniques) was used.

Figure 112005073388200-pat00011

The equivalent function is

Figure 112005073388200-pat00012

The corresponding matrix D is a pair of corner matrices whose i th element Di is

Figure 112005073388200-pat00013

Since all quantities of the matrix M are non-negative (non-negative), this calculation converges in one place.

According to the present invention, a ground wire mesh corrosion diagnosis software is prepared by using a mathematical method and a numerical method. This software is a graphic screen in its entirety and is easy to operate, so if you input only the conductor data of the ground wire network, the program will automatically generate the topology diagram and measurement plan drawing. The fault section can be identified and intuitively represented in the figure. 4 is a diagnostic software process flow diagram. The basic procedure first reads the topology file *. Brh of the ground network, and then determines the measurement to identify the ground network corrosion in the ground structure of the ground network. Measure the input resistance and transition resistance between each ground lead by the measurement method and obtain the measurement document * .msr. The following calculation procedure is based on the analysis of corrosion and disconnection of conductors in each section based on the phase structure and measurement results. The resistance value Rk of each section conductor is obtained by optimization analysis of the grasping equation. If the analysis result reaches the specified precision request, the analysis calculation is stopped and the result Rk is stored as * .out. Judging the disconnection of the conductors in each section based on the threshold, calculate the corrosion degree of the conductors in each section, save it as * .dia, and export the analysis result.

Since the point of disconnection is, in principle, regarded as a special type of corrosion, it is necessary to consider how much corrosion should be considered as a conductor corrosion breakdown. There is always a constant error in the absolute value of the electrical resistance calculation and the actual value of the conductor in each section of the ground wire network obtained from the measurement of the electrical function between the ground conductors of the ground wire network. Only the relative value between the conductor resistance calculations in each section is meaningful in determining the failure point. Therefore, the resistance limit between the disconnection point and the non-disconnection point must be automatically determined based on the distribution of these resistance values, and it must be confirmed based on the threshold judgment. The present invention establishes the threshold method in different permissible situations using artificial neural network through a large amount of simulation.

When grasping the ground wire network, there will be a certain difference between the drawing of the actual construction and the phase structure of the network, and there will be the influence of the cable groove. The analysis indicated that the grasping error due to this tolerance is not so large that the impact on the break point can be resolved by adjusting the threshold. Another part of the grasping system is a measuring system that precisely measures the microelectrical function (input resistance or transition resistance) between the ground wire and the ground lead. The input resistance between the ground leads is in the mΩ level, and this grasp system solves the problem of precisely measuring small resistances in the mΩ level in the presence of external disturbances. The small resistance micro-measuring device designed in the present invention has the capability of accurately measuring digitally under external interference. The principle is to inject a large current (20 ~ 30A) between ground wires and ground wires to increase the proportion of signal and noise to measure the potential difference between the wires and the input current to obtain input resistance or to measure the potential difference between other wires. Get In case of normal operation of the measuring device in the substation, when the corrosion of the ground wire network is judged, taking into account the case where the electrode environment is very deteriorated, a series of common anti-blocking measures are taken in the measuring device to prevent the interruption of the single chip computer and the single chip computer program. Guaranteed ability. The basic performance of the ground wire mesh corrosion determination system measurement device is to accurately detect small signals under disturbance. Thus, the entire electrical circuit of the design contains several module parts: overvoltage protection, range switching, sampling / maintenance, A / D, digital main board. If all electrical functions between all ground leads are measured, firstly the workload is large and secondly some measurement results may overlap. Therefore, the present invention adds an automatic confirmation method to the diagnostic software by measuring the main element analysis principle. After inputting the diagnostic software into the ground structure of the ground wire network and the position of the ground lead, analysis and the ground lead number of the electric function to be measured are provided.

The description of the attached drawings in which the substation ground wire network corrosion and disconnection points of the present invention, the method of measuring and measuring the detection system, combined with the embodiment is as follows. In this embodiment, the disconnection point identification experiment was conducted for the newly constructed 220 kV substation. In the experiment, artificially cut a conductor of one line of the ground wire network. The operation sequence for identifying the corrosion and disconnection points of the substation ground wire network of the present embodiment is as follows.

Step 1 Determine the measurement method: Enter the phase structure of the ground wire network and the position of the ground lead into the diagnostic software. Determine which part of the ground lead between the input and transition resistors will be measured.

Step 2: Measure the input resistance or transition resistance by the measurement method established in step 1.

(a) Inject a large DC current (around 25A) into the ground wire network. A dc cross-current source of approximately 25 amperes shall be applied between the ground leads of any two lines of the ground wire network with an external incremental supply. If it is relatively hard to find a cross-current source at a construction site, it can be replaced with a 180 A / h battery. The use of a DC power source avoids the influence of the AC power. Applying a current can suppress a disturbance signal in the ground wire conductor.

(b) Measure the voltage between each wire. The measurement system maintains the same instantaneous value of the multi-channel signal and measures the voltage U and I at the same time by using the measurement method of sampling / maintaining the external signal, thereby obtaining the same instantaneous value of U and I. Thus, the effects of unstable factors such as the charge of the battery voltage can be eliminated, and accurate input resistance between the two ground leads can be obtained.

(c) Measurement results are communicated with grasp analysis software and sent directly to diagnostic software.

Step 3: Check the corrosion and disconnection status of the conductors in each section of the ground wire mesh.

(a) Check the resistance of the conductors in each section of the grounded wire network after corrosion: through the input resistance or transition resistance between the grounded wire grounding conductors measured by the prepared diagnostic software (Fig. 4) and the input grounded wire network position structure. The resistance of the conductor in each section of the ground wire network is obtained.

(b) Conductors in each section are compared with the resistance of each conductor obtained through the measurement structure and the design resistance value obtained by calculation and analysis. After the corrosion (or after the completion of the construction of the new ground wire network), depending on the change of conductor resistance in each section, it is judged whether or not the conductor is disconnected in each section by the threshold value E. If it is a new ground wire network, it is judged that there is a weld failure or a missing welding condition. After designing and completing the ground wire network, the length, cross-sectional area and material of the conductors in each section have already been checked, so the design resistance is constant. Therefore, the difference in the resistance of each conductor calculated represents the difference in the degree of corrosion.

The measuring device structure of this embodiment is as shown in FIG. The first module is the input electrical circuit and includes two parts: voltage limit protection and expansion circuit. By selecting the appropriate expansion circuit, the modulation of the signal is reduced to tightly control the moving and warming shifts.

The second module is a multichannel simulation switch circuit that includes multichannel switches, sampling / maintenance, range switching and module switching. The instantaneous collection of each sample of each circuit is converted into data quantities and sent to the single-chip computer motherboard.

The third module is the core circuit of a single chip computer and includes data processing, system restoration and data communication. After the microprocessor obtains the result of switching the module, the microprocessor performs the calculation according to the predesigned calculation method and transmits the calculation result to the computer. All of the above-described modules can use products sold in the market.

Fig. 6 is a software flowchart of the measuring device single chip computer of this embodiment. First, the DC current is applied between the conductors to be measured according to the requirements, and the measurement conductors of the potential difference between the measurement conductors are placed.The measurement process first initializes each part of the measurement system, and then gives a measurement start distance command from the computer. Proceed with data sampling and module conversion. If the result is abnormal, take another sample. All 300 samples are taken. After sampling, the measurement results are corrected and the results are sent to the measurement document * .msr of the diagnostic software.

In this embodiment, the measuring device takes a precise electronic screen through the box, and the hardware system separates the simulation circuit and the data electrical circuit, separates the power of the data circuit chip, thickens the ground line, surrounds the ground line, and separates each performance module. Take measures, such as using “gurard” electrical circuits. The software design adds the ability to extend the software time at the entrance of the main program and program the I / O port, taking steps to set repeat play, control command repeat execution, command duplication, data wave filtering, data processing, etc. Secured resistance. All of these are anti-jamming measures that are frequently used.

A partial structural diagram of the ground wire network of this embodiment is shown in FIG. 7. Cut 5-6 conductors before the experiment. The diagnostic software directly exports the result as shown in FIG. Gray in the figure indicates the degree of corrosion and black indicates the breakage phenomenon. The calculation data of each horizontal branch circuit is shown in Fig. 9 according to the grasping result document. 12 branch circuits in the figure are 5-6 conductors identified in FIG. If the set resistance increase multiplier is 1.2 or less, the conductor will not be corroded. If the set resistance increase multiplier is 3 or more, the conductor will be disconnected. In Figure 6, the fault can be considered as a 5-6 branch circuit and is in full agreement with the design results. Field measurements make people happy. The break point location obtained by analyzing and analyzing the measured data and diagnostic software is consistent with the actual situation. The experimental results satisfy the needs of people and verify the grounding network corrosion and disconnection point grasping principle, the accuracy of the method and the possibility of the system. In addition, the results of the ground wire mesh corrosion detection and the actual ground conductor corrosion conditions obtained by digging the ground wire mesh part basically coincide, and the error is within 8%.

While exemplary embodiments of the invention have been described with reference to the accompanying drawings, the invention is not limited to these exact embodiments, but various modifications and changes are intended to be within the spirit and scope of the invention as set forth in the following appended claims. It is apparent to those skilled in the art.

The single chip computer for measuring the micro input resistance or the transition resistance of the ground wire network designed in the present invention and the diagnostic software plotted on the base of the window construct a single grasping system. It is a ground wire network break point and corrosion detection system that combines centralized measurement and calculation with a computer as the core. In other words, it is an industrial computed tomography machine that checks ground wire break points and checks for corrosion and new ground wire networks. The grasping result using the method of the present invention basically matches the corrosion situation of the actual ground conductor obtained by digging the actual part, and the error is within 8%, and it is possible to efficiently identify the disconnection state of the ground network conductor. It has a relatively high accuracy to meet the requirements of field measurements. This corrosion detection method is simple and accurate, and is not limited by the field operating conditions, and efficiently judges the failure of the ground wire network under the condition of not breaking down without power failure to guarantee construction quality and solve the concealed problem of the ground wire network. Help protect and scientifically manage your network. Major accidents can be prevented in advance, resulting in very large economic and social benefits. The present invention is not only a ground wire mesh corrosion inspection system but also a means for efficiently inspecting a ground wire mesh weld leakage and a weld defect during construction after completion of a ground construction. In other words, the quality of the construction of the ground wire network is secured by identifying and analyzing the welding defect and the welding leakage situation of the ground wire network. At the same time, it can be used for corrosion detection of metal pipe (water pipe, gas pipe, oil pipe).

Claims (4)

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  4. In the method of identifying the corrosion and disconnection points of the substation ground wire network,
     1) connecting the two ground leads of the ground wire network with a DC power supply and applying a large DC current to the ground wire network;
     2) measuring the voltage between the two ground leads and the current of the circuit to obtain an input resistance or transition resistance between the two ground leads;
    3) determining which input conductors and transition resistances between the ground conductors should be measured based on the phase structure of the ground wire network and the positions of all the ground conductors, and measuring the input resistance and the transition resistance which are the determined measurement targets;
    4) After inputting the survey result and the phase structure of the ground wire network to the diagnostic software, the diagnostic software analyzes and obtains the resistance value of the conductors of each part. And comparing the design resistance value obtained by calculation and analysis to determine whether the conductor of the ground wire network is disconnected and the corrosion situation.
    In the second step, the voltage between the conductors and the magnitude of the applied current are measured through measurement, and the voltage U and the current I are simultaneously measured to obtain the same instantaneous values of voltage and current, so that the measurement is performed between the two ground conductors. Obtaining the input resistance and the transition resistance of,
     How to identify the points of corrosion and breakdown of the substation grounding network.
KR1020050123788A 2005-12-15 2005-12-15 A method for detecting grounded network erosion and broken point of substation KR100657855B1 (en)

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Publication number Priority date Publication date Assignee Title
CN102540013A (en) * 2011-12-27 2012-07-04 广东电网公司韶关供电局 Transformer substation grounding network frequency response test device
CN102680820A (en) * 2012-05-08 2012-09-19 湖州电力局 Automatic testing and diagnosing system for corrosion fault points of grounding grid of substation
CN105137279A (en) * 2015-07-16 2015-12-09 吉林大学 Grounding grid breakpoint diagnostic method based on transient electromagnetic abnormal ring principle
CN105182169A (en) * 2015-10-10 2015-12-23 国网山西省电力公司临汾供电公司 Defect screening detection method and apparatus of grounding network upper guide body wire
CN105242173A (en) * 2015-09-14 2016-01-13 吉林大学 Frequency domain electromagnetic method-based grounding grid fault automatic diagnosis method
CN105425049A (en) * 2015-10-29 2016-03-23 国网浙江省电力公司台州供电公司 Method of testing geodetic network earthing resistance
CN107615086A (en) * 2015-04-15 2018-01-19 库珀技术公司 For system, the method and apparatus of the integrality for diagnosing electric conductor bearing system
US10114061B2 (en) 2016-11-28 2018-10-30 Kohler Co. Output cable measurement

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JPS59200974A (en) 1983-04-28 1984-11-14 Chubu Electric Power Co Inc Device for measuring earthing resistance
KR20000037146A (en) * 2000-04-10 2000-07-05 정재기 A new technical method and equipment for the grounding resistance measurement on power service
KR20020028168A (en) * 2002-02-20 2002-04-16 나용균 Sing line existence and nonexistence check method of ground connection rail track
KR20050001898A (en) * 2003-06-26 2005-01-07 학교법인 인하학원 A variable frequency inverter-type high power ground resistance measuring device and measuring method based on PC
KR20050021668A (en) * 2003-08-25 2005-03-07 한국전력공사 Ground resistor analysis system

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JPS59200974A (en) 1983-04-28 1984-11-14 Chubu Electric Power Co Inc Device for measuring earthing resistance
KR20000037146A (en) * 2000-04-10 2000-07-05 정재기 A new technical method and equipment for the grounding resistance measurement on power service
KR20020028168A (en) * 2002-02-20 2002-04-16 나용균 Sing line existence and nonexistence check method of ground connection rail track
KR20050001898A (en) * 2003-06-26 2005-01-07 학교법인 인하학원 A variable frequency inverter-type high power ground resistance measuring device and measuring method based on PC
KR20050021668A (en) * 2003-08-25 2005-03-07 한국전력공사 Ground resistor analysis system

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102540013A (en) * 2011-12-27 2012-07-04 广东电网公司韶关供电局 Transformer substation grounding network frequency response test device
CN102680820A (en) * 2012-05-08 2012-09-19 湖州电力局 Automatic testing and diagnosing system for corrosion fault points of grounding grid of substation
CN107615086A (en) * 2015-04-15 2018-01-19 库珀技术公司 For system, the method and apparatus of the integrality for diagnosing electric conductor bearing system
CN105137279A (en) * 2015-07-16 2015-12-09 吉林大学 Grounding grid breakpoint diagnostic method based on transient electromagnetic abnormal ring principle
CN105242173A (en) * 2015-09-14 2016-01-13 吉林大学 Frequency domain electromagnetic method-based grounding grid fault automatic diagnosis method
CN105182169A (en) * 2015-10-10 2015-12-23 国网山西省电力公司临汾供电公司 Defect screening detection method and apparatus of grounding network upper guide body wire
CN105425049A (en) * 2015-10-29 2016-03-23 国网浙江省电力公司台州供电公司 Method of testing geodetic network earthing resistance
US10114061B2 (en) 2016-11-28 2018-10-30 Kohler Co. Output cable measurement

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