JP2005183385A - Grounding power electrode and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To protect power and a communication system by effectively generating discharge inside a grounding electrode. <P>SOLUTION: In regard to the grounding power electrode and a manufacturing method thereof, the grounding electrode is formed of a cylindrical discharge tube and a core provided in the discharge tube and electrically connected to a lower stage part of the discharge tube. In order to dispersively generate discharge, the core is formed with a plurality of spiral discharge electrodes in the peripheral surface of the core, and thickness of the lower stage part of the core is formed smaller than that of an upper stage to relay speed of the surge current of travelling waves and to obtain reflected waves and surface effect. In the plurality of discharge electrodes, holes are arranged at positions corresponding to the electrode to easily discharge through a triode discharge electrode. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a grounding electrode, and more particularly to a power grounding electrode (functional grounding electrode) that effectively generates a discharge at two points on the same electrode that are electrically connected to protect the power and communication system, and its It relates to the production method.

  In the current advanced information society, power and communication facilities are increasingly developed. However, the development of devices that protect these facilities from various abnormal conditions and abnormal voltages is currently delayed.

  Damage caused by failure of power and communication equipment is spread over a wide range of unspecified numbers, causing confusion for society as a whole. Therefore, it is necessary to investigate the exact cause and take appropriate measures when an accident occurs. An accident caused by such a natural phenomenon is difficult to predict and has a large scale. Therefore, an accurate failure cause analysis and countermeasures are required.

  The fault current at the time of power system line faults and the lightning strike current caused by lightning strikes can cause a great deal of damage to the equipment connected to the line because of its so-called pulse characteristics that reach a peak value in a short time. Therefore, a protection facility having a short-time removal capability that can use the instantaneous rise of the voltage and current in reverse, detect the voltage from the magnitude and the rise, and respond to it each time is required.

  The above-mentioned protective equipment plays an important role in protecting related equipment in which grounding in power and communication equipment is electrically linked, and preventing electric shock and fire on the human body.

  However, the concept of grounding so far is based on several grounding principles, grounding electrode, ground electrode and improvement of construction method using grounding resistance reducing material added to the electrode, and analysis of ground potential rise during and after grounding design. The mainstream has been the mainstream, and little effort has been made to improve and develop the ground electrode itself.

  Also, some researchers have made efforts to improve the ground electrode itself by using various abnormal phenomena that occur in the power system, but grounding has improved various problems that are difficult to predict such as abnormal voltage and transient phenomenon. Despite being an electrode, there were problems such as finding new defects.

  For example, in order to reduce the grounding resistance of existing general grounding electrodes, it is mainly used to embed them in the ground by the deep hitting method or boring method and to add the grounding electrode in parallel to obtain the target installation resistance. Has been. However, this method is effective in places where the specific resistance to the ground is low, but is not satisfactory in highly resistant soils such as earth and sand.

  In addition, in the above method, when a voltage such as a lightning strike or an abnormal switching voltage that causes a very high voltage in a very short time period flows into the ground electrode, an instantaneous rise in ground potential occurs around the ground electrode. At the same time, there is a problem of inducing instantaneous abnormal voltage to other adjacent ground electrodes. Such a momentary increase in earth potential can, of course, cause damage to human life as well as damage to the surrounding facilities where the ground electrode is buried.

  In addition, a grounding electrode such as a mesh makes the voltage induced in each facility in the building almost equal when an abnormal voltage flows in by electrically binding the bottom rebar of the building, and removes the potential difference. It is a concept. However, since the construction area is large and must be reflected from the design of the target building, there is a problem that additional grounding becomes difficult.

  The above two methods have no specific principle, and their performance has been affected by the specific resistance to the ground and the structural parameters determined by the construction method.

  On the other hand, focusing on the fact that the surge voltage is very high and this high voltage can be turned off by discharge, a needle-like installation bar has been developed overseas. As shown in FIG. 1, this grounding rod is configured to induce a discharge in the ground by attaching a needle to a conventional general grounding rod. This needle-shaped grounding rod discharges in the ground when a high voltage such as a surge is applied in highly resistant soil, and can effectively suppress an instantaneous increase in ground potential. However, in low-resistance soils, reliable operation is not guaranteed, and when the frequency of underground discharge increases, the soil component deteriorates due to discharge heat and instantaneous pressure, and the ground resistance in the normal state increases on the contrary. . In addition, it is pointed out that the construction method is inconvenient, and this needle-shaped grounding rod is also used in limited areas such as the transmission lines of power companies and communication lines of communication companies in Korea. Is not used much.

  In order to solve such a problem, for example, an arc induction type grounding rod with a needle has been developed as disclosed in Patent Document 1.

  2 and 3, when the lead terminal (11) formed on the upper stage of the grounding rod (9) is electrically connected, the arc induction type grounding rod with a needle breaks down when a lightning strike occurs. The fault current that flows through the lead terminal (11), first through the lead terminal (11), and through the lead terminal (11) is applied to the needle holder (5-8) attached to the grounding rod (9). It is configured to be transmitted to the discharge tube (10) through the arc induction coil (13) connected to the lower stage of the grounding rod (9) via the needle (1-4) mounted so as to be movable in the circumferential direction. Is done.

  However, in such a conventional arc induction type needle grounding rod, the arc induction type coil (13) connected between the grounding rod and the discharge tube can induce the impedance of the arc induction type grounding rod circuit so that the discharge can be induced. The arc induction coil mainly induces various side effects, such as the durability of the arc induction coil against the inflow of moisture inside the arc-guided ground rod with a needle and the large current during lightning strike. . Therefore, there is a problem that it is difficult to apply to the power system.

Korean Patent No. 0399924 (registered 2002.5.27)

  The object of the present invention has been devised in order to solve the above-mentioned problems. Two points on the same pole that are electrically connected, that is, the same polarity by utilizing the short-time steep characteristics of the surge. By effectively generating a discharge between the two electrodes having a noise, the neutral point residual voltage due to the imbalance of the three-phase load of the power system operated in a normal state is dealt with by the abnormal pulsed surge entering the power system. As a result, the relay can be discharged through the surface of the grounded electrode and treated effectively, and it is possible to ensure the reliable operation of the protection relay even in the event of a power system failure in a direct grounding installation environment. It is to improve the reliability.

  In order to achieve the above object, the present invention provides a grounded electrode manufacturing method in which a cylindrical discharge pipe and a core rod which is installed on a shaft in the discharge pipe and is electrically connected to a lower stage portion of the discharge pipe are installed. In the method: The core rod has a plurality of discharge electrodes spirally formed on the outer periphery of the core rod in order to disperse discharge, and the surge speed delay, reflected wave and skin effect (skin wave) when applying a surge ( The lower part of the core rod is formed to be thinner than the upper part so that a skin effect occurs, and this is wrapped with a dielectric, and the plurality of discharge electrodes are discharged through a tripolar discharge electrode (used by trigatron). It is characterized in that a hole is arranged at a corresponding position of the discharge electrode so as to easily occur.

  In another aspect of the present invention, the discharge tube is formed of stainless steel in a substantially cylindrical shape, and is provided with a plurality of spiral three-electrode discharge electrode holes so that discharge is easily performed by the three-electrode discharge electrode; The lead terminal is integrated with the lower part, the lower step part is thinner than the upper end and the central part, and is formed of stainless steel, and is inserted into the longitudinal direction of the discharge pipe; and is formed of an insulating material; An insulator for fixing the upper part; made of stainless steel, a core rod holder for fixing the insulator and fixed to the upper part of the discharge pipe; and a wedge-shaped stainless steel for fixing the lower part of the core bar A ground electrode tip fixed to the lower part of the discharge pipe, and the core bar is made of tungsten or nichrome, the upper part is pointed, and the lower part is formed in a needle shape wider than the upper part, Hole for the above three-pole discharge electrode Provided is a power ground electrode provided with a plurality of discharge electrodes spirally attached at the center of the core rod and a dielectric attached to the lower outer periphery of the core rod at positions corresponding to each Is done.

  According to still another aspect of the present invention, a stainless steel tube having a substantially cylindrical shape is formed, and a bolt thread for a discharge tube for fitting the discharge tube is formed on the inner periphery of both end portions. A discharge tube provided with a plurality of spiral three-pole discharge electrode holes for easy operation; a lead terminal is integrally formed in the upper stage and the lower stage is thinner than the upper end and the central part, and is formed of stainless steel; A deep rod bolt thread is formed on the outer periphery of the tip of the lower step, and a core rod inserted in the longitudinal direction inside the discharge pipe; formed of an insulating material in a cylindrical shape with an open bottom surface, An insulator that is provided with a fixing hole for fixing the core rod, and an upper portion of the core rod is inserted and fixed therein through the fixing hole for fixing the core rod; and is formed of stainless steel and has a size corresponding to the insulator. The through hole for fixing the insulator is the lower part A screw thread for the core rod holder is provided on the periphery, and the bolt screw thread for the discharge tube and the bolt thread for the core rod holder are coupled with the insulator inserted into the through hole for fixing the insulator. A core rod holder to be fixed; made of stainless steel, the upper portion has the same diameter as the discharge pipe, the lower portion is formed in a wedge shape, and the center portion of the upper step surface has a bolt thread for the core rod in the vertical direction. A core rod insertion bolt thread of a size corresponding to this is formed so that it can be coupled to the discharge pipe bolt thread formed in the lower stage of the discharge pipe on the outer periphery of the upper stage. A bolt thread for a ground electrode tip is formed, and a ground electrode tip fixed to the discharge pipe is provided. The core rod is made of tungsten or nichrome and has a sharp upper portion compared to the upper portion. Wide bottom A plurality of discharge electrodes spirally attached at the center of the core rod at positions corresponding to the respective three-pole discharge electrode holes; and attached to the lower outer periphery of the core rod A power ground electrode is provided, characterized in that a dielectric is provided.

  The insulator is provided with fixing bolts at both ends of the center of the side surface, and the core rod holder is connected in parallel with a parallel additional ground electrode connected to both ends of the center of the side surface corresponding to the fixing bolt holes. A bolt hole for an additional electrode may be formed, and a fixing bolt hole having the same shape may be provided so that it can be coupled to the fixing bolt hole of the insulator at the bottom center of the parallel additional ground electrode bolt hole. .

  The tip of the ground electrode drains the water flowing into the discharge pipe into the ground, and discharges the generated pressure to the outside when a discharge occurs. One or more drainage and discharge holes are formed in the vertical direction between the bolt bolts for the tip, and a fixed screw thread is formed at the center of the bottom surface to insert and fix additional electrodes in series in the upper step direction. It's okay.

  As described above, according to the power ground electrode and the manufacturing method according to the present invention, when an abnormal voltage having a very short rise time enters the power system by effectively generating discharge on the same polarity. The neutral point residual voltage due to the imbalance of the three-phase load when the power system is normal can be processed. For this reason, the protection relay can be operated reliably, and an abnormal voltage such as a lightning strike having large energy can be effectively processed, so that it can be used for all facilities having electric power and communication equipment.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the present specification and drawings, components having substantially the same functional configuration are denoted by the same reference numerals, and redundant description is omitted.

  The configuration of the power ground electrode according to the present embodiment will be described with reference to FIGS.

  FIG. 4 is a cross-sectional view showing the configuration of the power ground electrode according to the present embodiment, FIG. 5 is an exploded perspective view showing the configuration of the power ground electrode according to the present embodiment, and FIG. 6 shows the power according to the present embodiment. It is a top view which shows a mode that the parallel additional ground electrode and the series additional ground electrode are adhered to the ground electrode for operation.

  The power ground electrode (100) of the present embodiment includes a discharge tube (110), a core rod (120), a discharge electrode (130), a dielectric (140), an insulator (150), a core rod holder (160) and It consists of a ground electrode tip (170).

  First, the discharge pipe (110) is an important part where internal discharge occurs, and has excellent heat resistance and pressure resistance to withstand the temperature and pressure increase that instantaneously increases during internal discharge, has high mechanical strength, and is relatively Made of stainless steel that can be configured at low cost. Moreover, the upper and lower sides of the discharge pipe (110) are opened, and the bolt thread (111) for the discharge pipe is formed on the inner periphery of both ends. The discharge tube (110) is provided with a triode discharge electrode hole (113) so that a triode discharge electrode is formed at a position corresponding to each discharge electrode (130) and discharge is easily caused.

  The core rod (120) is made of stainless steel, and the lead terminal (121) is integrally extended to the upper step portion, and the diameter of the lower step portion is narrower than the upper step portion and the central portion. Is formed with a core rod bolt thread (123) and inserted into the discharge pipe (110). Here, the reason why the lower part of the core rod (120) is formed smaller than the upper part is that, as the voltage and frequency are higher, the current is easier to move from the surface of the conductor, and the surge current is caused by traffic congestion. , Surge charge reaching the lower stage is instantaneously accumulated in the upper stage, and the conditions for easier discharge are established. Therefore, it is desirable that the lead terminal (121) of the core rod (120) is provided with an application lead joint nut (125) that is electrically and mechanically connected to an external application lead.

  Further, the discharge electrode (130) is made of tungsten or nichrome having a high melting point in order to improve heat resistance, and a needle-like electrode having a sharp upper step and a wide lower step is formed in the center of the core rod (120). It is formed by adhering to a spiral. Here, the discharge electrode (130) uses the characteristic that the non-uniform electric field formation at the needle-to-flat plate (side surface of the discharge tube) electrode is more intense than the other forms of electrodes, and the surge current is a traveling wave. In order to prevent damage to the discharge electrode (130) and the discharge tube (110) due to concentration of internally generated heat in one place, the heat was dispersed and arranged in a spiral shape.

  In addition, the lower part of the core rod (120) is inserted into the dielectric (140). As the material of the dielectric (140), epoxy resin, bakelite, polystyrene, crosslinked polyethylene (XLPE), polyethylene (polyethylene), polycarbonate, polyglass, etc. are used. . The reason for using the dielectric (140) is that the surge flowing through the core rod (120) moves at the speed of light, but the conduction speed of this surge is reduced to the square root of the dielectric constant by using the dielectric (140). It is because it can be made. This induces a larger potential difference between the potential applied to the discharge electrode (130) at a certain point and the discharge tube (110) in contact with the ground. In addition, the dielectric (140) generates a reflected wave that is generated in a direction opposite to the progress of the surge when the surge passes through a different medium, and instantaneously increases the voltage applied to the discharge electrode (130) to discharge the discharge tube. It serves to increase the potential difference from (110).

  On the other hand, the insulator (150) is formed of an insulating material, and a core rod fixing fixing hole (151) for fixing the core rod (120) is formed in a cylindrical shape with an empty central portion in the upper portion. The lead terminal (121) is inserted through the core rod fixing fixing hole (151) to secure a distance between the lead terminal (121) and the discharge pipe (110). In the insulator (150), fixing bolt holes (153) are formed at both ends of the lower side of the side surface so as to be fixed to the core rod holder (160) by the fixing bolt (105).

  The core rod holder (160) is made of stainless steel, and has an insulator fixing through hole (161) having a size corresponding to the insulator (150). The core rod holder bolt thread (163) is formed on the lower outer periphery. ), And with the insulator (150) inserted into the insulator fixing through hole (161), the bolt screw thread (111) for the discharge pipe and the bolt screw thread (163) for the core rod holder are coupled and fixed. To do. Further, the core rod holder (160) is formed with parallel additional ground electrode bolt holes (165) at both ends of the side surface, and the fixing bolt (105) is fastened to the bottom surface of the parallel additional ground electrode bolt hole (165). A fixing hole (153) having the same shape as the fixing bolt hole (153) is provided at a position corresponding to the fixing bolt hole (153) of the insulator (150).

  Here, when the target ground resistance cannot be obtained only by the power ground electrode (100), the core rod holder (160) has a parallel additional ground electrode bolt hole (165) at both ends of the center of the side surface as shown in FIG. ) To the parallel additional ground electrode (101). Also in this case, the insulator (150) is formed of an insulating material. The reason is to prevent the abnormal voltage from being discharged in advance before the abnormal voltage reaches the discharge electrode (130) at the time of surge intrusion, and it flows through the lead terminal (121) of the core rod (120). The surge increases to the peak value within a short time. As a result, creeping discharge is generated between the lead terminal (121) of the core rod (120) and the discharge pipe (110) before reaching the discharge electrode (130), and the soil is chemically deteriorated. As a result, the normal operation failure of (100) is caused. Therefore, since the discharge is generated only inside the discharge tube (110), it is necessary to ensure an appropriate creepage distance. For this reason, an insulator is inserted between the lead terminal (121) and the discharge tube (110). .

  The tip of the ground electrode (170) is made of stainless steel, the upper part has the same thickness as the discharge pipe, the lower part has a wedge shape, and the core screw bolt thread ( 123) A core rod insertion bolt thread (171) is formed so as to be connectable to the shaft 123). In addition, the ground electrode tip bolt thread (173) is configured so that the ground electrode tip (170) can be coupled to the discharge pipe bolt thread (111) formed in the lower stage of the discharge pipe (110) on the outer periphery of the upper stage. Is formed and fixed to the discharge pipe (110).

  The tip of the ground electrode (170) drains moisture that has entered the discharge pipe (110) into the ground, and discharges the pressure generated when the discharge occurs to the outside. One or more drainage and pressure relief holes (175) are formed vertically downward between the ground electrode tip bolt thread (173). In addition, when the ground electrode tip (170) is difficult to obtain the target ground resistance only by the power ground electrode (100), the center of the bottom surface is connected so that the series additional ground electrode (103) can be connected as shown in FIG. Thus, a fixing thread (177) capable of press-fitting and fixing the series additional ground electrode (103) upward is formed. In addition, when the series additional ground electrode (103) is not required, a deep core can be easily inserted by inserting a strong core-like one that matches the fixing screw thread (177).

  Hereinafter, the operation of the power ground electrode according to the present embodiment will be described with reference to FIGS. 4 to 8d (particularly, FIGS. 7a to 8d).

  FIG. 7a is a waveform diagram showing a basic waveform of a surge that induces the operation of the ground electrode, FIG. 7b is an enlarged view of a rise portion (increase wave) of the waveform of FIG. 7a, and FIG. FIG. 8A is a waveform diagram showing a current waveform applied to the power ground electrode, and FIGS. 8B and 8C are points (lead terminals) where a surge flows into the power ground electrode. FIG. 8D is a waveform diagram showing a current waveform measured immediately under the discharge electrode when a surge is introduced and a discharge is generated.

…（数式１）
Rは接地抵抗，ρは大地固有抵抗，ｌは接地電極の長さ，ｒは接地電極の半径である。 First, when the electrical system is in a normal operating state, the voltage remaining at the neutral point of the system should be removed quickly, which is closely related to the ground resistance of the power ground electrode (100). . That is, it is desirable that the ground resistance is low for smooth removal of the neutral point residual voltage, and when the power ground electrode (100) is buried in the ground, the ground resistance is reduced according to the following formula 1.

... (Formula 1)
R is the ground resistance, ρ is the earth resistivity, l is the length of the ground electrode, and r is the radius of the ground electrode.

  Also, in an environment where the neutral point direct grounding system is used, such as in Korea, when an abnormality occurs in the electrical system, a protective relay that operates in conjunction with the system is installed to protect the equipment on the line. Operate quickly. Since the operation performance of the protection relay is also determined by the magnitude of the fault current, in this case, the lower the ground resistance determined by the mathematical formula (Formula 1), the better the protection performance. In the power ground electrode according to the present embodiment, the contact area with the ground increases several times or more due to the connection between the discharge pipe (110) and the tip of the ground electrode (170). Ensures reliable operation.

  On the other hand, when an abnormal voltage such as a lightning surge or a switching surge flows in, rapid removal from the system is required. At this time, the surge flowing into the power ground electrode (100) can be turned off by grasping and utilizing the traveling characteristics inside the power ground electrode.

  In other words, the neutral point residual voltage processing capability is determined only by the ground resistance value under normal conditions in which only a high-frequency component having a smaller size is considered in the state of 60 Hz, which is a relatively low frequency compared to the surge. However, the surge turn-off capability is determined by how much the voltage that induces discharge is reduced when an abnormal voltage such as a surge enters. That is, since the size is very large and reaches a very high peak value in a short time interval, if these values are known, the distance between two points of the same polarity that can generate a potential difference that can be generated by discharge can be calculated.

  To help understand this, the operation principle of the power ground electrode with respect to surge will be described with reference to FIGS. 7a to 7c. The power ground electrode (100) connected to the system has a surge like the waveform of FIG. 7a. Intrusions lead to the lead terminal (121) along the applied lead, and the ground potential starts to rise. This ground potential rise is greatest at the site where the power ground electrode (100) (A in FIG. 7c) is embedded as shown in FIG. 7c, and is exponentially inversely proportional to the distance from the power ground electrode (100). Decrease. If the power ground electrode does not generate an internal discharge in response to a surge, the potential of ΔV rises at another ground electrode (B in FIG. 7c) that is separated from the power ground electrode by S.

  However, when a discharge occurs inside the power ground electrode, the potential at the point where the power ground electrode is buried decreases rapidly, thereby decreasing the potential applied to the other ground electrode.

  When a surge enters the power ground electrode, it passes through the lead terminal (121) and flows into the discharge electrode (130) of the core rod (120) and the corresponding three-pole discharge electrode hole (113). In this case, unbalanced electrolysis is formed due to the rapidity of the surge, and internal discharge occurs when the air breakdown voltage exceeds 30 kV / cm.

  As shown in FIGS. 7a and 7b, the surge rise time (Tf) and fall time (Tt) are very short, and a value of 1.2 × 50 μs is used in Korea and Japan. In other words, in the case of lightning strike voltage in Korea and Japan, the time required to rise to 100 million to 1 billion V is about 1.2 μs.

In the bare wire not covered with the dielectric, the surge moves at the speed of light of 3 × 10 ⁸ m / s. Therefore, the distance that the surge voltage moves is about 360 m during 1.2 μs up to the peak value. That is, the surge voltage causes a potential difference between the bare wires of 360 m.

At this time, different potential distributions occur between the points of the bare wire, and a potential difference is generated between the two different points during the progress of the surge. Discharge occurs when this potential difference exceeds 3 kV _dc per mm, generally referred to as air breakdown strength.

  Various parameters such as humidity in air, temperature, and type of electrode used are considered as parameters for determining the discharge start voltage. In general, the conditions under which discharge is relatively likely to occur due to the presence of moisture and various ionic substances in the ground are discharged at a voltage lower than the theoretical condition. Therefore, what actually becomes a problem is the distance between two points for applying a voltage of 3 kV at 1 mm intervals in a peak value of 100 million V. In the calculation, this distance is only 1.08 cm, but it is actually difficult to experimentally generate discharge at such a distance.

  Accordingly, the impedance of the power ground electrode is hardly changed, and another process is required to be discharged at any time against a surge that suddenly increases. For this reason, in the power ground electrode (100) of this embodiment, the lower part is made thinner than the upper part of the core rod (120), and the dielectric (140) is added to compensate for the thickness of the lower part.

  Such processing enhances the generation of reflected waves of surges passing through different media and the skin effect determined by the voltage and frequency, and passes through the core rod (120) to form the dielectric (140 ), The surge speed is delayed in inverse proportion to the square root of the dielectric constant of the dielectric, as shown in Equation 2 below, and the potential difference between the discharge electrode (130) and the discharge tube (110) is increased. In this way, the skin effect of the high frequency surge as shown in Equation 3 causes an increase in potential entrainment in the reflected wave generated when passing through the different medium and the diameter of the lower portion of the core rod (120), and the discharge electrode (130 ) And the discharge pipe (110).

…（数式２）

…（数式３）
ここで，ｌは電流の浸透深さ，ωは２πｆで，ｆは周波数（Hz），ρは材料の導電率，μは材料の透磁率である。 Internal discharge occurs at the moment when the above value exceeds the dielectric breakdown strength of the internal insulating medium of the power ground electrode (100). The internal discharge of the power ground electrode (100) is continuously generated along each discharge electrode (130) attached in a spiral shape, and the surge energy is converted into light, heat and sound energy, which corresponds to this energy. The rise in ground potential is suppressed.

... (Formula 2)

... (Formula 3)
Here, l is the current penetration depth, ω is 2πf, f is the frequency (Hz), ρ is the conductivity of the material, and μ is the permeability of the material.

  According to the operation principle as described above, an increase in ground potential at the time of surge inflow is suppressed, and the degree of suppression increases as the surge voltage entering the power ground electrode (100) increases rapidly. This effect is combined with the viewpoint of human life and equipment protection at the ground electrode buried point as shown in FIG. 7c.

  Hereinafter, experimental results using the power ground electrode according to the present embodiment are shown in FIGS. In the experiment method, an impact current generator (not shown) was connected to the lead terminal (121) of the power ground electrode (100), and the discharge pipe (110) was grounded. Here, the impact current generator is a built-in measuring instrument that can measure the waveform of the applied current and voltage. In addition, when an impact current is applied by the impact current generator and a discharge is generated inside the power ground electrode (100), the CT (instrument variable) is used to measure the surge current consumed in the discharge electrode (130). The CT output was connected to a separate oscilloscope. Since the first experiment is a comparison experiment with the occurrence of internal discharge, the experiment was conducted for the case where no internal discharge occurred. For this reason, the discharge electrode (130) inside the power ground electrode (100) was removed before the experiment. 8a and 8b show the results of applying the impact current in the state of the above.

  FIG. 8a shows the current waveform applied to the power ground electrode. The x-axis and y-axis of the figure are 5 μs and 10 kA on a scale, respectively, and a current of 8 × 20 μs in duration and a maximum value of about 25 kA is applied. Has been.

  FIG. 8b is a waveform diagram showing a voltage waveform measured at a point (lead terminal) where a surge flows into the power ground electrode. The scales of the x-axis and y-axis are 20 μs and 2 kA, respectively, and the duration is 1 A voltage of 2 × 50 μs and a maximum value of about 6 kV was measured.

  On the other hand, when the discharge in the power ground electrode (100) is generated, the discharge electrode (130) is installed in order to see the effect of suppressing the rise in ground potential, and then the impact current of the same condition is applied to the power ground electrode (100). 8c and 8d show the result of the discharge generated inside the.

  At this time, the waveform of the impact current measured at the lead terminal (121) is the same as that when the discharge electrode (130) is removed from the power ground electrode (100) as shown in FIG. 8a. Because of the measurement, the figure is omitted. In FIG. 8c, the x-axis and y-axis indicate 20 μs and 2 kV, respectively, and a voltage of about 1.2 × 40 μs and 3.8 kV is measured. It was observed that the potential increase was suppressed by about 1/3.

  In addition, in order to observe the degree of decrease in the applied impact current due to the occurrence of discharge at the power ground electrode (100), the current waveform when CT is installed under the discharge electrode (130) and this output is measured by a separate measuring instrument. Is shown in FIG. 8d. The x-axis and y-axis indicate a scale of 5 μs and 7 kV, respectively. As shown in FIG. 8d, a current of about 5 kA was measured immediately below the discharge electrode (130) where internal discharge occurred in the power ground electrode (100). Considering that the current applied to the power ground electrode (100) is 25 kA, this is drastically reduced to about 20% or less, and about 80% of the applied impact current is reduced to the power ground electrode (100). It means that it has been converted into heat, light, and sound energy by internal discharge.

  The result obtained in this experiment was an experimental result at 25 kA, which is the average value of lightning current generated in Korea, and the lightning voltage was about 100 million V or more, so it was not considered in this experiment. Assuming that the magnitude of the voltage is 100 million V or more, the voltage rising within 1.2 μs is expected to have a shorter rise time. Therefore, the power ground electrode (100) according to the present embodiment is more reliable. The operation is guaranteed.

  Therefore, according to this experiment, it is possible to effectively remove the voltage remaining at the neutral point of the power system during normal operation through the ground, guarantee the operation performance of the protection relay for interrupting the fault current at the time of abnormality, When various abnormal voltages enter the power system, the surge voltage and current are effectively turned off by the discharge inside the power ground electrode, the rise in ground potential around the ground electrode is suppressed, and the voltage is lowered to reduce human life and power. The equipment can be protected.

  In addition, in the construction method, a method using a deep-blow method and a boring method, which are relatively easy to embed underground, and additional construction of series and parallel ground electrodes to reduce ground resistance, as well as a relatively narrow space. But construction is possible.

  In addition, by introducing a tripolar discharge electrode into the electrode structure, surges flowing into the power ground electrode can be effectively processed at a lower voltage, and the characteristic that abnormal voltage is a traveling wave is utilized. The ground electrode internal electrode is arranged in a spiral shape and the release hole is provided to properly disperse and release the internal energy of the ground electrode to prevent the ground electrode from being damaged by internal pressure expansion and provide a drainage hole. This makes it possible to effectively remove the water that has flowed into the power ground electrode.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to the example which concerns. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Understood.

  The present invention relates to a ground electrode, and in particular, can be applied to a power ground electrode for effectively generating a discharge at two points on the same electrically connected pole to protect power and a communication system, and a method for manufacturing the same. It is.

The perspective view which shows the structure of the conventional needle-shaped installation stick | rod. Sectional drawing of the conventional arc induction type grounding rod with a needle. The exploded perspective view of the conventional arc induction type grounding rod with a needle. Sectional drawing which shows the structure of the functional installation electrode for electric power by this embodiment. The disassembled perspective view which shows the structure of the functional installation electrode for electric power by this embodiment. The top view which shows a mode that the parallel additional ground electrode and the series additional ground electrode are adhered to the power ground electrode by this embodiment. The wave form diagram which shows the basic waveform of the surge which induces the operation | movement of a ground electrode. Enlarged view of the rise waveform in Fig. 7a FIG. 3 is a conceptual diagram of ground potential rise when a surge enters the ground electrode. The wave form diagram which showed the electric current waveform applied to the power ground electrode. The wave form diagram which showed the voltage waveform measured from the time (lead terminal) when the surge flowed into the functional installation electrode for electric power. The wave form diagram which showed the voltage waveform measured from the time (lead terminal) when the surge flowed into the functional installation electrode for electric power. The wave form diagram which showed the electric current waveform measured just under the discharge electrode at the time of discharge.

Explanation of symbols

110 Discharge tube 113 Triode discharge electrode hole 120 Core rod 130 Discharge electrode 140 Dielectric
150 Insulator 160 Core rod holder 170 Ground electrode tip

Claims (5)

In a method for producing a ground electrode comprising a cylindrical discharge pipe and a core rod installed on an axis in the discharge pipe and electrically connected to a lower step portion of the discharge pipe:
The core rod is formed with a plurality of discharge electrodes in a spiral shape on the outer periphery of the core rod in order to disperse discharge.
The lower part of the core rod is made thinner than the upper part so that the speed delay of the surge wave, the reflected wave, and the skin effect occur when the surge is applied, and this is wrapped with a dielectric,
A method of manufacturing a power ground electrode, wherein the plurality of discharge electrodes are arranged such that holes are disposed at corresponding positions of the discharge electrodes so that discharge easily occurs through the tripolar discharge electrodes. A discharge tube formed of stainless steel in a substantially cylindrical shape and provided with a plurality of spiral holes for a triode discharge electrode so that discharge is easily performed by the triode discharge electrode;
A lead bar is integrally formed with the upper stage part, and the lower stage part is thinner than the upper end and the central part, is formed of stainless steel, and is inserted into the longitudinal direction of the discharge pipe;
An insulator formed of an insulating material and fixing an upper portion of the core rod;
A core rod holder formed of stainless steel, fixing the insulator, and fixed to the upper part of the discharge pipe;
A ground electrode tip formed of stainless steel in a wedge shape, fixing a lower portion of the core rod, and fixed to a lower portion of the discharge pipe;
With
In the core rod,
Made of tungsten or nichrome, the upper part is pointed and the lower part is wider than the upper part. A plurality of discharge electrodes attached in a shape;
A dielectric material attached to the lower outer periphery of the core rod;
A ground electrode for electric power, characterized in that is provided. It is made of stainless steel in a substantially cylindrical shape, and a bolt thread for a discharge tube is formed on the inner periphery of both ends to form a discharge tube bolt thread. A discharge tube provided with a hole for a triode discharge electrode;
Lead terminals are integrated in the upper part, and the lower part is thinner than the upper and center parts, and is formed of stainless steel. Deep rod bolt threads are formed on the outer periphery of the lower part, and the length of the inside of the discharge pipe is long. A core rod inserted in the direction;
An insulator that is formed of an insulating material in a cylindrical shape with an open bottom surface, a core rod fixing fixing hole is provided on the top surface, and an upper portion of the core rod is inserted and fixed therein through the core rod fixing fixing hole;
It is made of stainless steel, and has a through hole for fixing the insulator corresponding to the size of the insulator inside, and a bolt thread for a core rod holder on the outer periphery of the lower part, and the insulator is used for fixing the insulator. A core rod holder for coupling and fixing the outlet pipe bolt thread and the core rod holder bolt thread in a state of being inserted into the through hole;
It is made of stainless steel, the upper part has the same diameter as the discharge pipe, the lower part is formed in a wedge shape, and the center part of the upper part surface can be connected to the bolt screw thread for the core rod in the vertical direction. Corresponding size of core screw insertion bolt thread is formed, and the bolt thread for the tip of the ground electrode is connected to the discharge pipe bolt thread formed in the lower stage of the discharge pipe on the outer periphery of the upper stage. And a ground electrode tip fixedly installed on the discharge pipe;
With
In the core rod,
Made of tungsten or nichrome, the upper part is pointed and the lower part is formed in a needle shape wider than the upper part. A plurality of spirally attached discharge electrodes;
A dielectric material attached to the lower outer periphery of the core rod;
A ground electrode for electric power, characterized in that is provided.   The insulator is provided with fixing bolts at both ends of the center of the side surface, and the core rod holder is additionally installed in parallel by connecting parallel additional ground electrodes to both ends of the center of the side surface corresponding to the fixing bolt holes. A pole bolt hole is formed, and a fixing bolt hole having the same shape is provided so as to be coupled to the fixing bolt hole of the insulator at the center of the bottom surface of the parallel additional ground electrode bolt hole. The power ground electrode according to claim 3. The tip of the ground electrode is
Moisture that has flowed into the discharge pipe is drained into the ground, and when discharge occurs, the generated pressure is discharged to the outside between the bolt thread for inserting the core rod and the bolt thread for the tip of the ground electrode. One or more drainage and pressure relief holes are formed in the vertical direction,
4. The power ground electrode according to claim 3, wherein a fixing screw thread is formed at the center of the bottom surface so as to insert and fix the additional electrode in series in the upper step direction.

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