KR100402062B1 - Apparatus for measuring ground resistance of transmission tower posts - Google Patents

Apparatus for measuring ground resistance of transmission tower posts Download PDF

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KR100402062B1
KR100402062B1 KR20010001493A KR20010001493A KR100402062B1 KR 100402062 B1 KR100402062 B1 KR 100402062B1 KR 20010001493 A KR20010001493 A KR 20010001493A KR 20010001493 A KR20010001493 A KR 20010001493A KR 100402062 B1 KR100402062 B1 KR 100402062B1
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South Korea
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current
ground
ground resistance
potential
transmission
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KR20010001493A
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Korean (ko)
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KR20010025613A (en
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정재기
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한빛이디에스(주)
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Abstract

The present invention focuses on the fact that the four tower angles of the transmission tower, which is a steel structure used as a support for the transmission line, are used as separate resistors in order to stably supply power, and the transmission lines are always present in the transmission tower during operation. The present invention relates to a tower ground resistance measuring apparatus for a transmission tower using tower leakage current.
In the present invention, instead of measuring the ground resistance by moving two electrodes along the ground surface by combining two voltage poles and two current poles, it is possible to measure the ground resistance by working only two voltage poles. It provides a very simple method of measuring ground resistance for measuring ground resistance of installed transmission towers. In addition, by eliminating the current pole, which is the most important part of the general ground resistance measuring instrument, and replacing the current of the current pole with leakage current that is always flowing to the ground in the transmission tower, it is simple in terms of the method and structure of the grounding resistance measuring device. As it is possible to measure the harmonic ground resistance of the transmission tower, which was difficult to measure with the existing ground resistance measuring instrument, it is considered that stable operation of the power equipment and high-quality power transmission are possible.

Description

Apparatus for measuring ground resistance of transmission tower posts}

The present invention relates to a grounding resistance measuring apparatus of a transmission tower (FIG. 3), which is a support of a transmission line, which is a component of an electric line, which is the basis of power transmission, and overcomes the point that the grounding resistance measurement was impossible with the conventional grounding resistance measuring device 31. A grounding resistance measuring device.Increasingly industrialized, informatized, and urbanized, modern society is characterized by consuming a large amount of energy in dense areas, the most convenient of which is simple to use, simple to transport, and free of pollution. The stable supply of power energy, which is used as an energy source, has become an important factor throughout the industry.The stable supply of power, an important energy source, requires not only stability from natural disasters such as lightning, but also high quality of electricity. To reliably transfer high-quality power generated from To ensure high quality and stable power supply, good grounding is essential, and grounding not only functions to protect humans from power and lightning, but also provides reference potential in terms of power business. In addition, grounding plays a very important role in returning fault currents in the event of a power system accident, as well as facilitating facsimile or computers in the home as the information society accelerates. The facilities such as image information and the Internet used are being used, and the damage and the amount of damage are relatively large. Therefore, the management of the earth resistance by measuring the accurate earth resistance is a big benefit nationally. One of the reasons why the earth resistance of the transmission tower cannot be measured by the conventional earth resistance measurement method is that the three phase and earth Leakage current 64 due to induced phenomenon and three-phase unbalanced current. The ground potential generated at the ground electrodes 15 and 16 by the leakage current 64 is the ground potential generated at the ground electrodes 15 and 16 by the current 14 of the current electrodes C1 and C2 (15 and 16 in FIG. 2). Interfering with, causes an error in the value of the ground potential difference measured by the voltage poles P1 and P2 (17 and 18 in FIG. 2). That is, not only the ground potential difference due to the current by the current poles C1 and C2 is measured, but also the ground potential due to unnecessary leakage current 64 is included, so that the ground resistance value larger than the ground resistance value due to the ground resistance measurement principle is measured. This reduces the reliability of the measured value.

In the present invention, by using the leakage current 64 which is one cause of the grounding resistance measurement of the transmission tower 41 of FIG. 3 reversely, an excellent concept of using the current pole in the ground resistance measurement method as the output current. In this method, the measuring operation is much simpler than the conventional measuring method, the measuring time is shortened, and the structure of the measuring instrument is also simplified.

As shown in FIG. 7, when the leakage current 64 flowing through the tower angle 51 of the transmission tower is used as the current pole (15, 16 of FIG. 7) instead, the ground potential is measured by the voltage pole (17, 18 of FIG. 7). By simplifying the measurement work and simplifying the lead wires of the current electrodes (15 and 16 in FIG. 7), it is possible to eliminate the difficult and time-consuming work of placing the current electrodes C2 at a distance of tens or hundreds of meters. When conducting earth resistance measurement for transmission towers installed in mountainous terrain, enormous convenience and time savings are expected.

In other words, after applying the existing ground resistance measurement method, the current pole C2 is placed several tens or hundreds of meters away from the current pole C1, and then the voltage pole P2 is moved by the distance by the distance in the direction of the current pole C2. When a constant resistance value is obtained while moving the bay in a constant direction, the measurement is changed to a very simple measurement method that terminates the measurement. In the end, the present invention is a simple concept that enables the application of the ground resistance, which is convenient and impossible to measure in the live state. It is an invention that has an excellent effect in terms of application.

Basically, the method of measuring ground resistance (FIG. 1) applies a current between the ground electrode 11 and the auxiliary current electrode 16 to be measured with a significant distance D (24 in FIG. 1) between the current electrodes 15 and 16. The voltage pole P2 (18) proceeds gradually from the point P1 (17) toward the direction C2 (16), and the potential V (15) ratio to the current I 14, i.e., the resistance value I / V is measured as the vertical axis. The graph 21 which made the distance one horizontal axis can be obtained. At this time, the ground resistance value of the target ground electrode 11 becomes the ground resistance value of the portion 22 which becomes a parallel line.

At this time, the condition that the correct ground resistance is measured first, the current 14 sent from the current pole C1 and the current pole C2 of the conventional ground resistance measuring instrument 31 is the ground electrode C1 (11) to measure the ground resistance and ground resistance For measurement, a single current loop must be formed through an arbitrarily placed ground electrode C2 (16), and second, the current (14) must be a single path back to the ground. If these two conditions are not met, A typical ground resistance curve cannot be obtained, and even if a typical ground resistance curve is obtained, the measured ground resistance value is inaccurate.

The reason why it is impossible to measure the ground resistance of the transmission tower using the existing ground resistance measurement method,

The first is leakage current 64 due to induction between three phases and the earth and unbalanced currents of three phases. The earth potential generated by the current 14 of the current poles C1 and C2 (15 and 16 in FIG. 2) and the earth potential generated by the leakage current 64 cause interference, and the voltage poles P1 and P2 (17, The value of the earth potential difference measured by 18) is not the value of the earth potential difference generated by the current poles C1 and C2, but the value of the earth potential difference due to unnecessary leakage current 64. A ground resistance value greater than the ground resistance value is measured, reducing the reliability of the measurement.

Second, the path of the current 14 generated by the ground resistance meter 31. The current 14 sent out from the ground resistance measuring instrument must flow through the current pole C1 (15 in FIG. 2) and the current pole C2 16, and all of the earth must be the path 33. That is, the ground potential should not be generated in structures other than the ground electrodes 11 and 16 necessary to measure the ground resistance. If the current path is applied to the transmission line during operation or construction is completed, in the case of two transmission towers, each transmission tower will be connected to the ground through the processing ground line 42, so that the current path 63 does not go through the new ground. In consideration of the multiple transmission towers, several tens of undesired current paths such as the current paths 63 are generated, so that the measurement of the ground resistance of the transmission tower 41 to measure the ground resistance becomes impossible.

Eventually, in the case of the transmission tower 41 in operation or when construction is completed, the reason is that there are tens or hundreds of current paths instead of the only current path which is a condition for ground measurement, and the leakage current 64 inevitably generated during operation. Ground resistance caused by this makes it impossible to measure ground resistance.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a top angle grounding resistance measuring apparatus of a transmission tower for a transmission line in operation.

1 is a view for explaining a general grounding resistance measuring method.

The method of FIG. 1 is a ground resistance measuring method that is most commonly used in the world, and the ground potential 34 of the ground electrode 11 to measure the ground resistance and the ground potential of the grounded electrode 16 which are placed to measure the ground resistance. 35 is formed by the currents 14 sent from the current poles C1 and C2 (15, 16), and the voltmeter between the voltage poles P1 while moving the voltage pole P2 18 in the direction of the current pole C2 by distance. By measuring the voltage 15 measured by and indicating the voltage 15 / current 14 value by distance as the vertical axis 19 and the distance as the horizontal axis 20, a typical ground curve 21 is obtained. The value 22 of the horizontally flat portion of the ground curve is the ground resistance value of the ground electrode 11 to be measured.

At this time, the condition that the correct ground resistance is measured is, first, the current 14 coming from the current pole C1 and the current pole C2 is the ground electrode 11 to measure the ground resistance and the ground electrode 16 which is arbitrarily poured to measure the ground resistance. A single current loop through must be formed, and second, the current 14 must return the earth to the ground. If these two conditions are not met, a typical ground resistance curve cannot be obtained, and even if a typical ground resistance curve shape is obtained, the measured ground resistance value is inaccurate.

2 is a view for further explaining the principle of the ground resistance measurement method of the general electric power of FIG.

FIG. 2 is a diagram for further explaining the principle of FIG. 1 and emphasizes that a current flowing from current poles C1 and C2 (15, 16) of a conventional ground resistance measuring instrument flows through a single path and necessarily passes through the earth. Doing. In addition, it is explained that the ground potentials 34 and 35 generated by this current must be caused only by the current 14 transmitted from the current poles C1 and C2 of the ground resistance measuring instrument.

Figure 3 is a schematic diagram easily explaining the structure and shape of the transmission line to be the ground resistance measurement object in the present invention.

4 is a ground diagram and a ground diagram of a transmission tower which is a ground resistance measurement object of FIG. 3;

5 is a view for explaining a case in which grounding measurement is possible for a transmission tower with a conventional grounding resistance measurement method.

In addition to the description of FIG. 5, two conditions must be satisfied to enable ground resistance measurement for a transmission tower. First, the processing line 42 should be in a state in which it is not connected to other transmission towers, and second, there should be no leakage current, so it can be measured by the conventional ground resistance measurement method only when no power is supplied.

6 is a view for explaining that in the case of a transmission line that is in operation, that is supplying power, it is impossible to measure by the conventional method.

6, the current paths of the current electrodes C1 and C2 (15 and 16) do not pass through the earth, and thus accurate ground resistance measurement is impossible. That is, the current path 63 does not contribute to forming the earth potential of the current pole C2 (16) placed for measuring the ground resistance and the earth potential of the transmission tower 41 to be measured. In addition, as the leakage current 64 flows to the ground through the main material 51 having the top angle, the ground potential separate from the ground potential by the current 14 discharged from the current pole is transmitted to the ground line 54, 55, 56) to prevent accurate ground resistance measurement.

Figure 7 is a view for explaining a method for measuring the ground resistance for a power transmission line in operation according to the present invention. In addition to the diagram of Figure 7 illustrates the current from the current poles C1, C2 (15, 16), The leakage current 64 flowing through the main body 51 of the tower angle of the transmission tower 41 was measured by the fastening current transformer 73, and the leakage current 64 was used as a current element, and the voltage poles P1 and P2 (17, 18) were used. Earth resistance is measured using earth potential between them as voltage element.

8 is a view for explaining a method of measuring the leakage current 64 in a state in which the fastening current transformer is fastened to the main body 51, which is a leg of the steel tower. Referring to the drawings of FIG. The type current sensor 73 can be attached and detached.

10 is a view for explaining the test performed by the method proposed in the present invention on the actual transmission line to verify the validity of the present invention.

11 is a schematic diagram of a measuring device for measuring ground resistance using leakage current in a live state according to the present invention;

12 is a view for explaining the current measuring device of FIG.

13 is a view for explaining the potential measuring device of FIG.

14 is a diagram for describing the converter circuit of FIG. 11.

FIG. 15 is a diagram for describing the ground resistance calculator of FIG. 11.

16 is a view for explaining the display device and the control device of FIG.

17 is a measured ground resistance curve measured in the traveling direction 101 of the steel tower in FIG. 10 with the method and apparatus of the present invention.

18 is a measured ground resistance curve measured in the 45 ° direction 102 of the steel tower in Figure 10 with the method and apparatus of the present invention.

FIG. 19 is a measured ground resistance curve measured in a vertical direction 103 with a steel tower in FIG. 10 by the method and apparatus of the present invention. FIG. 20 is a waveform of ground potential signal measured by a specific transmission tower. FIG. 21 is shown in FIG. 20. Fig. 22 is a graph of a frequency analysis result of the waveform shown. Fig. 22 is a waveform of a current signal measured by a specific transmission tower. Fig. 23 is a graph of a frequency analysis result of the waveform shown in Fig. 22.

<Description of Signs of Major Parts of Drawings>

11. Grounding electrode subject to earth resistance measurement (mesh composed of copper wire and grounding rod)

12. Grounding electrode which is made of metal body such as grounding copper wire and grounding rod and is the object of grounding resistance measurement.

13. A voltage source or a current source (direct current or alternating current) that sends a current required to generate a ground potential to the target ground electrode 11 whose ground resistance is to be measured to the current electrodes C1 and C2.

14. Ammeter measuring current I necessary to generate earth potential at ground electrode 11 to be measured

15. Current electrode C1, which is one element of two current electrodes serving as a passage of current flowing through the target ground electrode 11 whose ground resistance is to be measured.

16. Another current pole C2 which forms a closed loop with current pole C1 (15) to allow current to flow.

17. Voltage pole P1 for measuring earth potential, an important voltage component for measuring ground resistance.

18. Voltage pole P2 for measuring earth potential, which is an important voltage component for measuring ground resistance.

19. Represent the resistance as the longitudinal axis of a typical ground resistance curve.

20. The horizontal axis of the typical ground resistance curve is the maximum distance between the current pole C1 and the current pole C2.

21. A typical ground resistance curve shows a straight line horizontally when normal measurements are made.

22. The value of the ground resistance of the grounding pole (11) to be measured as the value of the straight section in a typical grounding resistance curve.

23. Surface

24. The longer the distance is the straight line distance (D) between the grounding pole (11) and the grounding pole (16) placed for measurement, the more typical ground curves are obtained.

31. The most commonly used ground resistance meter

31. Display window (number, needle, scale, etc.) showing the ground resistance value measured for each distance while moving the voltage pole P2 from the voltage pole P1 to the current pole C2.

33. A good ground resistance curve (21) in the case where the current output from the conventional ground resistance measuring device (31) flows through the earth while having the current path through the current electrodes C1 and C2 as the current path between the current electrodes C1 and C2. ) Is obtained.

34. The earth potential of the grounding target to be measured caused by the current flowing between the current poles C1 and C2.

35. Ground potential of C2 ground electrode, which is an auxiliary ground electrode placed in order to measure the current generated by currents C1 and C2. It refers to the ground potential formed solely by the current sent from the ground resistance measuring instrument 31.

41. A power transmission line, which is a supply path of electric power, is divided into a steel structure 44, a power line 43, a processing ground line 41, an insulator 45, and a base 55.

42. Processed ground wire, which is one of the components of 41, which protects the power line 43 of a transmission line from lightning and the like and returns to the fault current in the event of a power line accident.

43. A component of the power transmission line of 41 is responsible for supplying power to a power line that is a power supply path.

44. A steel structure as a component of the power transmission line of 41, wherein the 42 and 43 are steel structures in the space so as to mechanically support the natural environment.

45. As one of the components of 41, electrical insulation is required between the power line 43 and the transmission tower 44. In general, an insulator is formed of a support made of glass, porcelain, or polymer material, which is called insulator. .

51. A steel structure connecting the base 56 and the transmission tower 44 of the earth as one element constituting the transmission tower of 44 is referred to as main material or tower angle.

52. As an element constituting the transmission tower of 44, an auxiliary steel structure for further strengthening the main material 51 is called an auxiliary material or sand material.

53. One of the elements constituting the transmission tower of 44 is an iron structure recessed inside the concrete of the base 56, which is called plinth material.

54. One of the elements constituting the transmission tower of 44 is an iron structure combined with the base 56, and is called an anchor material.

55. One of the elements constituting the transmission pylon of 44 above is a concrete structure that is firmly supported on the ground.

56. As one of the components of the transmission line of 41 above, the copper wire is composed of a ground copper wire, which is a safety measure for minimizing the contraction of electric power and electric shock.

57. Transmission line direction defined for convenience of explanation

61. Another transmission tower to explain the electrical phenomenon when multiple transmission towers exist

62. When measuring the ground resistance with the existing ground resistance measuring instrument 31, the normal current path meeting the condition that the ground resistance can be measured accurately.

63. Current path that makes accurate ground resistance measurement impossible when measuring ground resistance with conventional ground resistance meter (31)

64. When the ground resistance is measured by the conventional ground resistance measuring device 31, it is called a leakage current as a current that makes a normal grounding measurement impossible.

71. Transmission tower earthquake measuring instrument using leakage current (63)

72. Execution switch to use as measurement signal when measuring ground resistance

73. Rogowski coil-type current sensor for measuring the leakage current, which is a removable clamp type current transformer has the advantage of being easily connected to the main material 51 of any form of steel tower.

74. Earth ground potential generated by the leakage current 64 flowing through the main material 51 during operation of the transmission line 41. Due to this earth potential, the ground resistance cannot be measured by the conventional ground resistance measurement method. In the present invention, the earth potential, which is a very important factor that enables the earth resistance measurement by using the earth potential.

75. Ground resistance measurement curve obtained by using the earth potential of 74, using this earth potential, and using the voltage poles P1 and P2

76. Ground resistance value to be calculated from the ground resistance measurement curve of 75

77. As a component of the current sensor of 73, the magnetic field generated by the leakage current 64 and the induction of the coil 79 become current again and circulated in the coil 79. This circulating current is converted by the current voltage converter 78, the current measuring terminal to which the leakage current 64 passing through the coil in the form of a voltage. Through this terminal, the leakage current is measured in the form of voltage.

78. Current voltage converter converting leakage current induced in sensor coil 79 into voltage form

79. Coil sensing current by electromagnetic induction phenomenon principle by magnetic field generated by current of leakage current 64

80. It has a structure that is mechanically and electrically separated so that it can be easily removed.

101, 102, 103,: Ground resistance measurement path for 345kV solid line

110: configuration diagram of the device proposed in the present invention

111. Current measuring device

112. Potentiometer

113. Ground impedance calculation unit

114. Converter circuit

115. Display equipment, control device

121. Operational Amplifiers

122. Filter circuit

123. offset circuit

124. Phase Correction Circuit

131. High input impedance circuit

132. Band stop circuit

133.Offset stop circuit

134. Phase correction circuit

141. Current conversion circuit

142. Potential Conversion Circuit

143. Simultaneous Conversion System

151.Digital Filter

152. Phase Computation Algorithm

153. Frequency Analysis Algorithm

154. Impedance Calculation Algorithm

155. Display Control

161. Resistance indicator lamp

162. Phase display lamp

163. Measurement Command Control Key

164. Display

The tower angle grounding resistance measuring apparatus of the transmission tower according to the present invention for achieving the above object is a current leakage current that acted as a factor of disturbance in measuring the ground resistance of the ground pole (56, 99) configured in the transmission tower in operation By using it as a pole, it is possible to eliminate the current generator existing in the ground resistance measuring instrument, and by constructing a measuring circuit for measuring leakage current instead of the current pole, it is unnecessary to design a complicated and demanding power supply device. By eliminating the work of pouring, the work time is shortened and the work time is shortened.

Using the device of the present invention (Fig. 7) is simpler than the conventional method of measuring the earth resistance (Fig. 1) that the user is accustomed to. Because there is no pouring work of the current pole, the method of measuring the voltage pole is the same as the conventional method of measuring the ground resistance.

The structure of this invention consists of 6 parts largely.

First, the power supply device necessary for transmitting the current 14 in the existing ground resistance measuring instrument is not necessary by using the leakage current 64 existing in the operating transmission tower, and the detachable leakage current is a device corresponding to the power supply device. A measuring device (Fig. 8) is used. The detachable current measuring device has a structure 80 that can wrap the main material 51 which is a leg portion of the steel tower, and can be easily attached to or detached from the main material 55. This structure 80 makes it possible to measure the necessary leakage current 64 without breaking the current sensor.

The leakage current 64 flowing through the main material 51 of the transmission tower generates a magnetic field to the outside, and the magnetic field penetrates the coil 79 so that the current corresponding to the leakage current 64 circulates inside the coil 79. This circulating current causes the leakage current 64 to be output to the output terminal 77 in the form of voltage by the current voltage converter 79. By providing the leakage current 64 information in the form of voltage obtained from the voltage output terminal 77 to the current measuring device 111, it replaces the current pole in the conventional ground resistance measuring device 31. The content of this part is the biggest feature of the present invention, it is possible to measure the ground of the transmission tower in operation.

Second, the magnitude of the leakage current transmitted from the current voltage converter 78 is a current measuring device 111 for processing current information in the form of voltage.

12 is a view for explaining the current measuring device 111 in detail. Between the current electrodes C1 and C2, the leakage current 64 information in the form of voltage is transmitted to the terminals C1 and C2 of FIG. However, the complete insulation amplifier is constructed so that the current applied from the current pole is not affected in the detection process. The maximum value of the detected current information is amplified by the operational amplifier 121 and amplified to be less than or equal to ± 10 V, which is the maximum value that can be accepted by the converter circuit 114. In addition, the current signal passed through the operational amplifier 121 removes the component corresponding to the noise by the filter circuit 122, and removes the DC component included in the current signal from which the noise component is removed by the offset circuit 123. do. Since the signal amplified by hardware and the noise component and the DC component are removed is a general change of phase, the signal is corrected to have accurate current information by passing it through a phase correction circuit 124 composed of an operational amplifier. 114).

Third, the input impedance of the ground potential input terminals P1 and P2 is considered to be a very important factor in determining how accurately the ground resistance can be measured by the influence of the leakage current 64. Has an electric potential measuring device 112 having a characteristic of minimizing an error in electric potential measurement by designing an input terminal having a value of 20 MΩ or more so that the earth potential can be measured accurately without the influence of the voltage pole application line length. 13 is an explanatory diagram for accurately measuring earth potential. The most essential condition for accurate earth potential measurement is, in principle, the input impedance between the measuring terminals P1 and P2 is infinite. To meet this condition, design a voltage follow circuit with an operational amplifier and design and manufacture a high input impedance circuit 131 so that the input impedance is 20 MΩ or more, so that the earth potential is not applied to the wires constituting the voltage poles P1 and P2. It is characterized by minimizing the error in measuring the earth potential input without voltage drop by putting all input terminals with large input resistance. The input ground potential information is band-stopped by the band stop circuit 132 configured as an operational amplifier to limit the leakage current and noise flowing to the ground electrode in the power equipment in operation as much as possible. In fact, since the component of the current flowing through the transmission tower of the transmission line is mainly observed up to 9 harmonics (540 Hz) when the reference is 60 Hz, harmonic components larger than 540 Hz may be treated as noise. 132) has a function of passing only a value of 1 dB or less and not allowing more bands to pass. In addition, the band-stopped ground potential information has the same function as to increase the accuracy of the current measuring circuit 111, and the DC component is removed by the offset blocking circuit 133. Since the signal which is band-stopped by hardware and the DC component is removed is a general change in phase, it is passed through a phase correction circuit 134 composed of an operational amplifier, corrected to have only complete AC information, and then converted into a converter circuit 114. To pass.

Fourth, the top angle current signal and the ground potential signal converted from the above are the converter circuit 114 having a function of digitizing the current information of the current measuring device 111 and the voltage of the ground potential through the voltage measuring device 112; Are input to the current converter 141 and the voltage converter 142, respectively, and are simultaneously converted into digital signals by the simultaneous conversion system 143. The function of this circuit is to simultaneously digitize the current information and the voltage information (A / D conversion) to minimize the phase difference between the voltage information and the current information by processing the voltage information and current information of the ground potential at the same time. 14 is a diagram for describing the converter circuit in detail. In general, when converting information from voltage and current signals into digital signals, the most important thing is the sampling time that determines how much information and how many bits to process once. To this end, the present invention is designed to sample at least 32 times a period of the frequency signal sent from the control device, and designed and manufactured to have a resolution of 1/65536 by performing 16-bit A / D processing once sampling. When calculating the phase difference between the voltage information and the current information by using the voltage information and the current information, it is necessary to sample the voltage information and the current information at the same time so that the accurate phase information can be calculated. Simultaneous conversion, which is a circuit that uses a technique of simultaneously digitizing the current converter circuit 141 and the potential converter circuit 142, which are D converters, and converting them into a 32-bit processor. The reason why the ground potential signal and the current signal are simultaneously converted in the present invention is to ensure the phase information of the potential and the current. The phase difference is obtained by subtracting the phase of the current, and the exact harmonic impedance is calculated by this phase difference. The.

Fifth, the display device and the control device 115. The display function displays the phase and ground impedance of the applied ground potential signal or current signal as the ground resistance value. The display device and the control device 115 include a measurement switch 163 for commanding a measurement, an LCD 164 for displaying a resistance value, and an LED 161 and 162 for displaying whether the display content is a resistance value or a phase, and the value thereof. It consists of the LCD 164 which expresses.

Sixth, the signal generation circuit and the ground impedance calculation unit 113, which are parts of the most important digital processors. This device receives the execution command from the control device 115 and processes the current information from the current poles C1 and C2 and the voltage information from the voltage poles from the voltage poles P1 and P2 corresponding thereto through the converter circuit 114. It transmits the ground impedance obtained by using the phase difference between ground potential information and leakage current information to the display device. 15 is a part for explaining the ground impedance calculator in detail. All of these functions are written in software, and the present invention uses DSP32, a 32-bit processor. The leakage current information and the earth potential information A / D converted at the same time in the simultaneous conversion system 143 pass through the digital filter 151 to become the noiseless clean leakage current information and the earth potential information. The ground voltage and leakage current information passed in this way are divided into real and imaginary parts corresponding to respective frequencies, and when processed in a relative concept, an error-free phase can be calculated. The present invention has a function 152 for processing a phase having an error of 0.1 degree or less. It processes the voltage information and current information of the required frequency part among the results of passing the phase calculation algorithm 152 and the frequency analysis algorithm 153 to calculate the impedance (154) in a space configured as a memory to be delivered to the display device. More specifically, the ground potential signal and the current signal transmitted to the ground impedance calculator 113 are obtained by frequency and phase for each frequency by the ON-LINE FFT operation. The phase difference between the potential and the current is calculated by subtracting the phase of the current from the phase of the potential thus obtained. For example, a normal FFT operation is a signal for processing a cos function and a sin function having a specific frequency component, that is, the potential in the present invention. The real and imaginary parts of a specific frequency component are obtained by taking the signal, the current signal, and the integrating integral, and using these real and imaginary parts, the magnitude ( Frequency [㎐] Voltage magnitude [V] Phase 60 3.5051 43.8 180 0.092337 -38 300 0.10234 -73 420 0.01131 -34 540 0.011969 -66

Frequency [㎐] Current magnitude [A] Phase 60 0.095645 -20 180 0.002589 -17.6 300 0.0049730 46.5 420 0.0022095 -80.6 540 0.00070194 73.9
As shown in Table 2, the tower angular current measured by a specific transmission tower actually includes various harmonic components such as 1, 3, 5, 7, and 9, and these values can be used to obtain respective harmonic currents and phases. Using the harmonic components of the earth potential and the harmonic components of the current as shown in Table 1 and Table 2, it is possible to calculate the ground impedance for each harmonic component, and the magnitude of the actual ground impedance is applied to each harmonic component. Divide the magnitude of the voltage by the magnitude of the current, and the phase is subtracted from the phase of the voltage by the phase of the current.

The effects of the present invention are as follows.

First, the leakage current occurring inevitably generated at the tower angle 51 of the transmission tower 41 while operating the measurement of the ground resistance of the tower angle 51 which has not been measured until the end of construction or during operation. 65), it is possible to measure the ground resistance of the transmission tower 41, which could not be measured by the conventional method (FIG. 6), thereby contributing to the supply of high-quality power by raising efficiency and efficiency in the operation of the transmission tower 41. Second, the ground resistance is measured by measuring the reference frequency 60 Hz and the ground impedance for each of the 3,5,7,9 harmonics based on the 60 Hz current component flowing through the transmission tower of the transmission line. Even if a lightning strikes or breaks into the steel tower, there is an advantage that the grounding performance can be evaluated stably.

Third, the leakage current 64 of the transmission tower 41, which previously acted as an obstacle of the ground resistance measurement, instead of the power supply device that generates the current of the current pole in the conventional measurement method using the ground resistance meter 31 By replacing the current sent from the current pole of the ground resistance measuring device 31, the structure of the equipment is simplified, and when manufactured in a portable manner, there is an effect of reducing the power consumption of the rechargeable battery.

Fourth, since the leakage current 64 of the transmission tower 41 is measured by using the leakage current 64 of the transmission tower 41, there is no inconvenience in that the current pole should be poured in tens or hundreds of meters when measuring the ground resistance. Therefore, simply by pouring only one voltage electrode (18 in FIG. 6) and measuring, the ground resistance measurement can be simplified.

Fifth, in general, the ground wire is installed with copper wire and copper rod, and the copper wire and copper rod installed in the soil is corroded by moisture and chemicals contained in the ground, and is corroded by ionization by leakage current. Is lowered. This reduction in grounding performance enables the measurement of the ground resistance in the live state in operation, thereby contributing to the high-quality power transmission of transmission lines and distribution lines.

Claims (3)

  1. Rogowski coil-type current measuring device having a detachable structure that can wrap the top angle main material 51 of the transmission tower, and outputs a leakage current 64 of the voltage form flowing through the main material (51);
    When the leakage current 64 is transmitted to the current electrode input terminals C1 and C2, the maximum value of the leakage current 64 is amplified by the operational amplifier 121 and then the noise component is removed by the filter circuit 122. A current measuring device 111 for removing the DC component by the offset circuit 123 and then correcting it to have accurate current information by passing the phase correction circuit 124;
    9 harmonics when the band of the earth potential transmitted by the high input impedance circuit 131 which receives the earth potential without voltage drop through the earth potential input terminals P1 and P2 is based on the 60 ㎐ current flowing through the pylon of the transmission line. 540 kHz), block more bands, and then remove the DC component of the earth potential blocked by the offset blocking circuit 133, and then pass through the phase correction circuit 134 to correct only complete AC information. Potential measuring device 112;
    The current information of the current measuring device 111 and the voltage information of the potential measuring device 112 are simultaneously received by the current converting circuit 141 and the potential converting circuit 142 which are 16-bit A / D converters and converted into digital signals. And a converter circuit 114 which simultaneously receives the voltage information and the current information converted into the digital signal by the simultaneous conversion system 143 having a 32-bit processor and digitizes them without time difference;
    The 60 kHz reference frequency and the phase and magnitude for each of the 3, 5, 7, and 9 harmonics for the leakage current and the ground potential signal converted into digital signals by the converter circuit 114 are obtained by the ON-LINE FFT operation. Subsequently, the phase difference between the leakage current and the ground potential is calculated by subtracting the phase of the current from the phase of the ground potential, and the ground impedance at the top angle is calculated by dividing the voltage magnitude of the ground potential by the current size of the leakage current. Part 113; And
    Display / control device 115 for displaying the ground impedance applied from the ground impedance calculator 113 as a ground resistance value
    Top angle grounding resistance measuring apparatus of the transmission tower, characterized in that consisting of.
  2. delete
  3. delete
KR20010001493A 2001-01-11 2001-01-11 Apparatus for measuring ground resistance of transmission tower posts KR100402062B1 (en)

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KR100687098B1 (en) * 2005-02-24 2007-02-27 제주대학교 산학협력단 remote measuring system for earth resistance
KR100725857B1 (en) * 2004-10-30 2007-06-08 한국전력공사 The device to measure the ground resistance using the leakage current in the ground conductor
KR100968046B1 (en) 2008-09-30 2010-07-07 한국전력공사 Method for ground resistance measurement of transmission tower equipped with overhead groundwires
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KR100968046B1 (en) 2008-09-30 2010-07-07 한국전력공사 Method for ground resistance measurement of transmission tower equipped with overhead groundwires
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