JP2010207057A - Lightning arrester - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lightning arrester capable of coping with an earth fault and a surge. <P>SOLUTION: A first diode 13 and a second diode 14 are connected in parallel, and reversed in the polarity. An inductance element 12 is connected to the first diode 13 and the second diode 14 in series. A surge absorbing element 11 is connected to the first and second diode 13, 14 and the inductance element 12 in parallel. The sum of a voltage drop in the first diode 13 and the second diode 14 and a voltage drop in the inductance element 12, against the earth current, is set to values lower than an operating voltage of the surge absorbing element 11. The sum of the voltage drop in the first diode 13 and the second diode 14 and the voltage drop in the inductance element 12, in a frequency band of surge components, is set to values higher than the operating voltage of the surge absorbing element 11. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a lightning arrester connected to ground. In particular, the present invention relates to a lightning arrester that can cope with surges and ground faults.

  In recent years, the number of thunderstorms has increased, and thus the frequency of lightning strikes has also increased. If lightning strikes, a fragile building electrical installation will cause extensive damage and enormous damage. There are examples of introducing equipotential bonding and integrated grounding systems that are less susceptible to lightning strikes in recent steel bars and steel buildings, but it is not yet common and the equipment cannot be easily updated, so even today, individual grounding systems are still in use. It is used in many buildings.

  In the case of a steel frame / reinforced concrete structure, which is a conductive building structure, individual grounding has a lot of harmful effects because, on the basis of the building potential, another unstable potential is introduced into the building. If there is a direct lightning strike on the building or a lightning strike near the building, the lightning damage will occur in the equipment and equipment in the building, so effective measures are required.

The building potential rise is caused by the product of the ground resistance of the building structure and the lightning current. This lightning current
(1) Due to direct lightning strikes,
(2) What happens when lightning strikes to other buildings due to the connection between buildings by metal conductors such as power / communication lines, water supply pipes or gas pipes, or (3) buried Since the electrical resistance of metal pipes is significantly smaller than the surrounding soil, lightning current to the ground flows into the building through the buried metal pipe. The increase in the building potential in the densely populated area is mainly caused by the above three reasons.

  In the case of an individual ground system, each ground pole is secured individually. Ideally, the ground resistance is 0Ω, and the respective potentials are fixed to 0V, and the potential difference between the ground electrodes does not appear, so there should be no mutual influence. However, in reality, there is a resistance in each ground electrode (including a building), and each ground electrode is not independent, which causes a problem. This is because the voltage applied between the ground electrodes appears as a difference in voltage drop due to the current flowing through each ground electrode resistance. Therefore, when there is a lightning strike, a surge voltage appears between the ground terminals. Since the power supply system is connected to the B-type ground electrode, the B-type ground electrode potential is superimposed on the power supply. Since the ground terminal is connected to the D-type ground electrode or the structure between the power source and the ground terminal of the electric equipment to be used, the surge voltage described above appears. In addition, a surge voltage due to another cause appears between the ground terminal and the power source / signal system or between the plurality of ground terminals via the ground system. This surge voltage can cause damage to electrical equipment.

  Another problem is the generation of abnormal voltage during power grounding. Specifically, the B class grounding of each transformer is connected to one B class grounding electrode. Here, when a non-grounded power supply line other than the grounded power supply line is grounded, the B-type ground electrode potential rises due to a voltage drop of the B-type ground electrode resistance having a common impedance. This potential can also affect the D-type ground electrode. For these reasons, an abnormal voltage is generated between the building and each ground electrode in the ground system.

  Here, a means for suppressing a potential difference due to a ground fault using a low voltage operation SPD (Surge Protective Device) is also conceivable. However, there are many environments where a ground fault occurs (1) there is no earth leakage breaker, or (2) even when there is an earth leakage breaker, it takes a long time to break. For this reason, the duration of the ground fault current is generally much longer than that of the surge. For this reason, when a normal SPD is used, there is a problem that it is not possible to cope with a large processing energy for processing a ground fault, and there is a possibility that the SPD may be damaged. It is highly possible that this ground fault phenomenon occurs at a considerable frequency including instantaneous ground faults.

  In order to achieve ground potential equalization, as a lightning arrester that can cope with ground faults, it can withstand continuous ground fault currents and lightning surge currents, and both voltage drops can be kept as small as possible. Is preferred.

  An object of the present invention is to contribute to equalizing the ground potential by providing a lightning arrester that can cope with ground faults and surges.

  Means for solving the above-described problems can be described as follows.

(Item 1)
A surge absorbing element, an inductance element, a first diode, and a second diode;
The first diode and the second diode are connected in parallel and the polarity is inverted,
The inductance element is connected in series with the first and second diodes,
The surge absorbing element is connected in parallel with the first and second diodes and the inductance element,
The sum of the voltage drop at the first diode and the second diode and the voltage drop at the inductance element in the commercial frequency band is set to a value lower than the operating voltage of the surge absorbing element, and the frequency of the surge component The sum of the voltage drop at the first diode and the second diode and the voltage drop at the inductance element in the band is set to a value higher than the operating voltage of the surge absorbing element. .

(Item 2)
The surge absorbing element includes a low voltage operating lightning arrester and a surge absorbing capacitor,
The lightning arrester according to item 1, wherein both the low-voltage operation lightning arrester and the surge absorbing capacitor are connected in parallel with the first and second diodes and the inductance element.

(Item 3)
The lightning arrester according to item 1, wherein the surge absorbing element is provided with a low voltage operating lightning arrester.

(Item 4)
The lightning arrester according to item 1, wherein the surge absorbing element includes a surge absorbing capacitor.

(Item 5)
Item 5. A lightning arrester comprising the lightning arrester according to items 1 to 4 and a current limiting resistor connected in series with the lightning arrester.

  According to the lightning arrester of this invention, the lightning arrester which can respond to a ground fault and a surge can be provided. As a result, according to the present invention, the potential difference between the grounds can be reduced.

It is explanatory drawing for demonstrating the condition where the lightning arrester which concerns on 1st Embodiment of this invention is used. It is a circuit diagram for demonstrating the lightning arrester which concerns on 1st Embodiment of this invention. It is a circuit diagram for demonstrating the lightning arrester which concerns on 2nd Embodiment of this invention. It is explanatory drawing for demonstrating the condition where the lightning arrester which concerns on 3rd Embodiment of this invention is used. It is a circuit diagram for demonstrating the lightning arrester which concerns on 3rd Embodiment of this invention. It is explanatory drawing for demonstrating the condition where the lightning arrester which concerns on 4th Embodiment of this invention is used. It is explanatory drawing for demonstrating the condition where the lightning arrester which concerns on 5th Embodiment of this invention is used.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. 1 and 2.

  FIG. 1 is an explanatory diagram schematically showing a state of a building to which a lightning arrester of this embodiment is attached. In FIG. 1, the code | symbol 1 has shown the building. A three-phase transformer 2 and a single-phase transformer 3 are arranged in a substation inside the building 1. One line of the three-phase transformer 2 and the neutral line of the single-phase three-wire transformer 3 are connected to the B-type ground electrode 4, and the D-type ground wire for safety measures paired with the power source is connected to the D-type ground electrode 5. And grounded. The building 1, the B type grounding electrode 4 and the D type grounding electrode 5 are connected to the ideal earth 6.

  The lightning arrester 10 of this embodiment is connected between the B class grounding electrode and the building. Further, current limiting resistors 7 are connected in series between the lightning arrester 10 and the three-phase transformer 2 and the single-phase transformer 3, respectively.

  The lightning arrester 20 of this embodiment is connected between the D-type ground electrode and the building. In this embodiment, the lightning arrester 20 has the same configuration as the lightning arrester 10.

  Hereinafter, the internal structure of the lightning arrester 10 will be described with reference to FIG.

  The lightning arrester 10 includes a surge absorbing element 11, an inductance element 12, a first diode 13, and a second diode 14 as main elements.

  The first diode 13 and the second diode 14 are connected in parallel and the polarity is inverted. Both the first diode 13 and the second diode 14 can be configured by a combination of a plurality of diodes. For example, the operating voltage can be adjusted by connecting a plurality of diodes in series. Specifically, the operating voltage can be adjusted to 2.1 V by connecting three diodes having an operating voltage of 0.7 V (forward direction) in series.

  The inductance element 12 is connected in series with the first diode 13 and the second diode 14. As the inductance element 12, for example, a coil wound around a high permeability toroidal core can be used.

  The surge absorbing element 11 is connected in parallel with the first diode 13 and the second diode 14 and the inductance element 12. In this embodiment, a low-voltage operation lightning arrester is used as the surge absorbing element 11. As such a low voltage lightning arrester, for example, GDT (gas discharge tube), MOV (metal oxide varistor) as a large capacity, ABD (avalanche breakdown diode), etc., although the capacity is small Can be used. In the case of GDT, there is a DC discharge start voltage of 70 V, and a short circuit is caused by discharge. Some MOVs are in the 10V range. There are ABDs of 10V or less, and they are connected in series with reverse polarity.

  In addition, as SPD mentioned above, what is generally used for the surge suppression of a voltage application part can be diverted. Of course, it is preferable to develop a low-voltage operation SPD more suitable for grounding purposes as in this embodiment.

  The sum of the voltage drop at the first diode 13 and the second diode 14 and the voltage drop at the inductance element 12 is set to a value lower than the operating voltage of the surge absorber 11 in a low frequency band such as a commercial frequency band. ing. For example, if the total voltage drop at the inductance element 12 and the second diodes 13 and 14 is 5 V, the operating voltage of the surge absorbing element 11 can be set to 8 V or more, for example. Thereby, the voltage drop of the inductance element 12 can be ignored with respect to the power supply frequency component such as the power supply ground fault, and the continuous current due to the ground fault can be prevented from flowing into the surge absorbing element 11.

  On the other hand, the sum of the voltage drop at the first diode 13 and the second diode 14 and the voltage drop at the inductance element 12 in the frequency band of the surge component is set to a value higher than the operating voltage of the surge absorbing element 11. . Here, in the present embodiment, a voltage is applied to the inductance element 12, the first diode 13, and the second diode 14 corresponding to the operating voltage of the surge absorbing element 11, and a current flows through them. Therefore, in selecting these diodes, it is desirable to select a diode having a current capacity that can withstand the current flowing corresponding to the operating voltage of the surge absorbing element 11.

  As apparent from the fact that the impedance of the inductance element 12 is generally represented by jωL, the voltage drop at the inductance element 12 varies depending on the frequency of the applied voltage. In general, the surge voltage is a high frequency, while the frequency of the commercial power supply is sufficiently low. Therefore, the inductance element 12 of this embodiment is configured to give a sufficient voltage drop to a high frequency such as a surge voltage and hardly give a voltage drop to a low frequency such as a commercial power supply. Detailed operation of the lightning arrester 10 of this embodiment will be described later.

  Since the internal structure of the lightning arrester 20 is the same as that of the lightning arrester 10, a description thereof will be omitted.

(Operation of the lightning arrester of this embodiment)
Next, the operation of the lightning arrester 10 according to the present embodiment will be described. Since the operation of the lightning arrester 20 is the same as that of the lightning arrester 10, the description thereof is omitted.

  The basic role of each element in the lightning arrester 10 is as follows.

  First and second diodes 13 and 14: A continuous current at the time of ground fault is passed. Since the ground fault current is generally an alternating current, an alternating current ground fault current can be caused to flow by using diodes having different polarities.

  Inductance element 12: Since the surge current frequency component has a large impedance, each diode is prevented from being damaged. On the other hand, since the impedance is low for the power supply frequency component, the inductance element 12 can be ignored. By causing the inductance element 12 and the first and second diodes 13 and 14 to have a voltage drop equal to or lower than the operating voltage of the surge absorber 11, the surge absorber 11 is protected against a ground fault current.

  This will be described in more detail below.

1. About the power supply frequency component due to the ground fault By making the forward voltage drop of the first and second diodes 13 and 14 smaller than the operating voltage of the surge absorbing element 11, the first and second diodes 13 and 14 is short-circuited, and no current flows through the surge absorbing element 11. Further, the voltage of the ground electrode when the first and second diodes 13 and 14 are short-circuited becomes equal to the structure potential. The inductance element 12 can be ignored in the power supply frequency component.

  In this embodiment, since the current limiting resistor 7 is connected, the ground fault current flowing into the diode can be suppressed. In other words, when the ground fault current flowing to the diode is suppressed only by the current limiting resistor 7, the first and second diodes 13 and 14 have values obtained by dividing the ground fault voltage by the resistance value of the resistor 7. A current capacity exceeding 1 is required.

2. About the high frequency component by a surge When the high frequency voltage by a surge is added to the lightning arrester 10 of this embodiment, the electric current which flows into each diode is suppressed by the inductance element 12. FIG. On the other hand, the surge absorbing element 11 is operated by a surge voltage and is short-circuited. The surge voltage is generally much higher than the ground fault voltage. In this case, a calculation example of the current flowing through the surge absorbing element 11 is as follows.

  The lightning arrester of this embodiment has an advantage that it can be applied without greatly changing the existing individual grounding configuration.

  Moreover, in this embodiment, the ground fault current at the time of a ground fault can be protected using a diode. Since the voltage drop at the diode is small, the surge absorber 11 can be operated at a low voltage. Furthermore, when the surge phenomenon is particularly long, the possibility of damage to the surge absorbing element 11 can be reduced by diverting the allowable current to the diode side.

(Second Embodiment)
Next, a lightning arrester 210 according to a second embodiment of the present invention will be described with reference to FIG. In the description of the lightning arrester 210, the description of the lightning arrester 210 that is basically common to the above described lightning arrester 10 will be simplified by giving the same reference numerals.

  The surge arrester 210 of this embodiment uses a surge absorbing capacitor as the surge absorbing element 11. Other configurations are the same as those of the lightning arrester 10 described above. The lightning arrester 210 can be used in the same manner as the lightning arrester 10.

  In addition, it is preferable to make the insertion capacity as small as possible in order to reduce the influence on the signal etc. of the lightning arrester aiming at voltage suppression. However, in this embodiment, the purpose is to make the potential between the ground electrodes equal. Therefore, if insulation at a low frequency such as a power supply frequency is ensured, a large capacity is preferable as a countermeasure against surges.

  In general, it should be avoided to increase the charge accumulated in the capacitor. For this reason, in the case of the lightning arrester 210 using a capacitor for absorbing surges as in the second embodiment, as a use, for a countermeasure against a surge current due to a short-time surge current or a magnetic coupling that does not cause charge accumulation, It is preferable to do.

  It is known that the capacitor voltage V (= Q / C) is determined by the accumulated charge Q and the capacitor capacitance C.

  In this embodiment, the inductance element 12 relaxes and discharges the accumulated charge in the capacitor as the surge absorbing element 11 and consumes it (Id × Vd) by the diode. Further, the ground wire resistance is inserted for use, and the stored charge can be discharged and consumed here.

  Other operations and advantages of the lightning arrester 210 according to the second embodiment are the same as those of the lightning arrester 10 according to the first embodiment described above, and thus detailed description thereof is omitted.

(Third embodiment)
Next, a lightning arrester according to a third embodiment of the present invention will be described with reference to FIGS.

  First, the situation where this lightning arrester is used will be described with reference to FIG. The power transmission cable used for three-phase 6.6kV high-voltage cable wiring is generally a twisted three cables that are insulated from the sheath that shields the central conductor through which the current flows. Grounded at the power transmission end side. In FIG. 4, three sheaths 301, 302, and 303 are shown for shielding each line of the three-phase high-voltage cable. These sheaths 301, 302, and 303 are considered to be measures against circulating current on the power receiving end side, but are generally not grounded. In FIG. 4, the lightning arresters 310, 320, and 330 according to the present embodiment are connected between the sheaths 301, 302, and 303 and a ground electrode 304 that represents the structure. Since these lightning arresters 310, 320, and 330 have the same configuration, the internal structure of only one lightning arrester 310 will be described.

  The lightning arrester 310 uses a surge absorbing element 311 shown in FIG. 5 instead of the surge absorbing element 11 in the first embodiment. In the description of the lightning arrester 310, the same reference numerals are used for the components that are basically common to the lightning arrester 10 that has already been described, thereby simplifying the description.

  The surge absorbing element 311 of the lightning arrester 310 includes a large-capacity low-voltage operation lightning arrester 3111 and a surge absorbing capacitor 3112. As in the first embodiment, the operating voltage of the large-capacity low-voltage operating lightning arrester 3111 is set to a value higher than the voltage drop due to the inductance element 12, the first diode 13, and the second diode 14 with respect to the ground fault current. ing.

  According to the lightning arrester of the third embodiment, if there is a direct lightning strike on the power transmission side building and a surge voltage is applied through the sheath, the large-capacity low-voltage operation lightning arrester 3111 operates as in the first embodiment, Each sheath can be shorted to the ground electrode 304. Thereby, the surge voltage superimposed on the high voltage line can be suppressed, and the high voltage line and the connected equipment can be protected.

  In addition, when using a large-capacity GDT lightning arrester that is a promising candidate for the SPD 3111 in this use state, the capacitor 3112 has an effect of relaxing the surge voltage increase rate and lowering the trigger voltage of the GDT.

  In addition, the lightning arrester of the third embodiment can be connected to one end which is normally ungrounded in each of the sheaths 301, 302 and 303, and both ends can be grounded. When both ends are grounded, a circulating current flowing through the sheath is generated between the insulated wire sheaths by the induced voltage generated by the interlinkage magnetic flux due to the three-phase current. However, in this embodiment, the path of the circulating current flowing through the sheath is the ground electrode 304, the diodes 13 and 14 on one end side, the sheath, and the diodes 13 and 14 on the other end side. That is, two sets of diodes are connected in series. Then, if the voltage that generates the circulating current is lower than the operating voltage of the diodes connected in series, the diode does not conduct, and therefore the generation of the circulating current in the sheath can be prevented. When the use condition of the high voltage cable is the rated current and the commercial power supply frequency (for example, 60 Hz to 50 Hz), the generation of the circulating current can be prevented by adjusting the number of diodes so as to satisfy the former condition. The inductance element 12 can be ignored at such a low frequency.

  On the other hand, high-order harmonic (ie, high frequency) current can flow through the surge absorbing capacitor 3112. Such a high-frequency current acts as a shielding current. That is, the high-frequency current flowing through each sheath cancels out the harmonic component magnetic field generated by the current flowing through the high-voltage cable and suppresses the leakage magnetic field. As the high-frequency component, it is necessary to satisfy ωL> 1 / ωC in order to set the circulating current between the sheaths to the canceling phase. Here, L is the inductance of the circuit formed by the insulated sheaths, and C is the capacitance of the surge absorbing capacitor 3112.

  In this embodiment, the ground fault current can be collected in the ground fault sheath. In a specific application example, if a ground fault occurs on the non-grounded 6.6 kV high-voltage power receiving end side, if this embodiment is not adopted on the power receiving end side of the sheath and is not grounded, the ground fault current will be received. It becomes a large circulation path that passes from the side grounding system through the ground and returns from the power transmission end sheath grounding portion to the sheath. By adopting this embodiment, the ground fault current at the time of ground fault returns to each sheath because the diodes of the lightning arresters 310, 320, 330 are short-circuited.

  Other operations and advantages of the lightning arresters 310, 320, and 330 according to the third embodiment are the same as those of the lightning arrester 10 according to the first embodiment described above, and thus further detailed description thereof is omitted.

(Fourth embodiment)
Next, a lightning arrester according to a fourth embodiment of the present invention will be described with reference to FIG. The lightning arrester 410 in 4th Embodiment is comprised similarly to the lightning arrester 310 of 3rd Embodiment. In the description of the present embodiment, the same reference numerals are given to the components that are basically the same as those already described, thereby simplifying the description.

  First, a situation where the lightning arrester 410 is used will be described. In this example, a so-called common ground electrode structure is adopted instead of the individual ground system shown in FIG. A common grounding electrode 401 for power supply is disposed inside the building 1. And the lightning arrester 410 of this embodiment is arrange | positioned between the common ground pole 401 and a building. In addition, a resistor 402 is connected in parallel with the lightning arrester 410 to suppress a current to the structure during normal operation. The building 1 forms a so-called Faraday cage and is grounded by a structure foundation or the like. In FIG. 6, reference numeral 403 is a three-phase high-voltage power cable, reference numeral 404 is a communication line, reference numeral 405 is a metal conductor (for example, a water pipe) introduced from the outside, reference numeral 406 is a D-type grounding wire with a covering structure, Reference numeral 4071 is a high permeability toroidal core, reference numeral 4072 is an arrester, reference numeral 408 is a class A grounding wire, and reference numeral 409 is a grounding pole representing a building (that is, a structure).

  As with the lightning arrester 310 of the third embodiment, the lightning arrester 410 of the present embodiment uses a surge absorption element 411 instead of the surge absorption element 11 of the first embodiment. The surge absorbing element 411 of the lightning arrester 410 includes a low voltage operation lightning arrester 4111 and a surge absorbing capacitor 4112.

  In the present embodiment, a common ground electrode 401 is provided separately from the representative ground electrode 409, and the lightning arrester 410 of the present embodiment is connected between them as shown in FIG. In the present embodiment, the first and second diodes 13 and 14 are connected in parallel with the resistor 402. Normally, only the resistor 402 is functioning. Therefore, for example, the leakage current from the electric device returns to the common ground electrode through the structure and the D-type ground wire. However, since the common ground electrode and the structure have the resistor 402, most of the current has a resistance value. It gathers on a small D-type grounding wire and does not flow into the structure. Therefore, the voltage drop of the structure can be reduced, and the structure potential is made constant.

  In the present embodiment, the ground fault current generated at the time of ground fault returns to the common ground electrode 401 through the D-type ground line 406 for the D-type grounded electrical device. When a ground fault occurs in the building 1, the ground fault current returns to the common ground electrode 401 through the D-type ground wire 406 connected to the building 1.

  If the building 1 and the D-type ground wire 406 are not connected, the first and second diodes 13 and 14 connected to the representative grounding electrode 409 are short-circuited, and a ground fault current flows through both diodes. Will flow.

  In addition, for Class B grounding of each transformer, by adding resistance to meet the electrical equipment technical standards, potential anomalies due to ground faults can be retained only in the ground fault transformer system, and current during ground faults is suppressed. it can.

  In the configuration of FIG. 6, when the common ground electrode 401 and the representative ground electrode 409 are connected only by a diode, the following inconvenience is expected. That is, an abnormal voltage may be generated for some reason, such as a ground fault to the building 1 or an external surge current intrusion due to a Faraday cage break. In this case, when only a diode is connected as described above, there is a risk of damage to the diode due to surge current. On the other hand, in this embodiment, since the grounding low voltage operation lightning arrester 4111 is used, the inductance 12 functions when a surge occurs, reducing the risk of diode damage, The low voltage operation lightning arrester 4111 is activated, and the potential difference between the common ground electrode 401 and the representative ground electrode 409 can be reduced. In addition, since the ground fault current flows through the diode, the low-voltage operating lightning arrester 4111 can be protected from the continuous ground fault current. Therefore, in this embodiment, stable use of the lightning arrester 410 can be expected.

  Since the other structure of this lightning arrester 410 is the same as that of the lightning arrester 310 of 3rd Embodiment, it abbreviate | omits detailed description further.

(Fifth embodiment)
Next, a lightning arrester according to a fifth embodiment of the present invention will be described with reference to FIG. The lightning arrester 510 in the fifth embodiment can be configured similarly to the lightning arrester 310 of the third embodiment or the lightning arrester 10 of the first embodiment. In the description of the present embodiment, the same reference numerals are given to the components that are basically the same as those already described, thereby simplifying the description.

  First, a situation where the lightning arrester 510 is used will be described. In this example, an individual grounding system is employed. In FIG. 7, reference numerals 501, 502, and 503 denote D-type ground lines. Reference numeral 504 denotes a ground electrode that represents the structure. The ground electrode 504 is configured using, for example, a part of the building 1.

  A lightning arrester 510 according to the present embodiment is disposed between the D-type ground wires 501 to 503 and the representative ground electrode 504 and between the ground wires 501 to 503. Since each lightning arrester 510 has the same configuration, it is represented using the same reference numeral. Moreover, since the internal structure of the lightning arrester 510 is the same as that of the lightning arrester 10 or the lightning arrester 310 already demonstrated, detailed description is abbreviate | omitted.

  Even in such a usage method, both the ground fault current and the surge current can be appropriately processed by the lightning arrester 510.

  In the present embodiment, the lightning arrester 210 shown in the second embodiment can be used when the type D grounding resistance is increased to suppress the surge current to a low level.

  Since the other structure and advantage of this lightning arrester 510 are the same as that of the lightning arrester 10 of 1st Embodiment, it abbreviate | omits detailed description any more.

DESCRIPTION OF SYMBOLS 1 Building 2 Three-phase transformer 3 Single phase transformer 4 B class grounding electrode 5 D class grounding electrode 6 Ideal earth 7 Current limiting resistor DESCRIPTION OF SYMBOLS 12 Inductance element 13 1st diode 14 2nd diode 301 * 302 * 303 Sheath for high voltage cable shields 304 Ground pole 311 Surge absorption element 3111 Large capacity low voltage operation lightning arrester 3112 Surge absorption capacitor 401 Common ground pole 402 Current suppression Resistance 411 Surge absorption element 4111 Large capacity low voltage operation lightning arrester 4111 Low voltage operation lightning arrester 4112 Surge absorption capacitor

Claims (5)

A surge absorbing element, an inductance element, a first diode, and a second diode;
The first diode and the second diode are connected in parallel and the polarity is inverted,
The inductance element is connected in series with the first and second diodes,
The surge absorbing element is connected in parallel with the first and second diodes and the inductance element,
The sum of the voltage drop at the first diode and the second diode and the voltage drop at the inductance element in the commercial frequency band is set to a value lower than the operating voltage of the surge absorbing element, and the frequency of the surge component The sum of the voltage drop at the first diode and the second diode and the voltage drop at the inductance element in the band is set to a value higher than the operating voltage of the surge absorbing element. . The surge absorbing element includes a low voltage operating lightning arrester and a surge absorbing capacitor,
The lightning arrester according to claim 1, wherein the low-voltage operation lightning arrester and the surge absorbing capacitor are both connected in parallel with the first and second diodes and the inductance element. The lightning arrester according to claim 1, wherein the surge absorbing element includes a low-voltage operation lightning arrester. The lightning arrester according to claim 1, wherein the surge absorbing element includes a surge absorbing capacitor.   A lightning arrester comprising the lightning arrester according to claim 1 and a current limiting resistor connected in series with the lightning arrester.

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