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A COAXIAL DISK SHUNT FOR MEASUREMENT IN THE HIGH-CURRENT CIRCUIT OF HIGH-VOLTAGE GENERATOR OF STORM DISCHARGES OF PULSES OF CURRENT OF ARTIFICIAL LIGHTNING WITH THE INTEGRAL OF ACTION UP TO 15 x [10.sup.6] J/OHM.

UDC 621.3.022: 621.319.53: 621.317.32

Introduction. US normative documents SAE ARP 5412: 2013 [1] and SAE ARP 5416: 2013 [2] define the requirements for amplitude-time parameters (ATP) of artificial lightning current pulses generated by the corresponding high-voltage lightning generators, commonly referred to as high-voltage generators of current of lightning (GCL), on electrical loads of aerospace equipment, tested for lightning. One of these types of powerful GCL reproducing the necessary ATP pulses of the simulated lightning current according to the requirements [1, 2] on the active-inductive load, was developed and created in 2007 by the staff of the Departments No. 3 of high-voltage pulse technology and No. 4 of electromagnetic tests of the Research & Design Institute <<Molniya>> of the National Technical University <<Kharkiv Polytechnic Institute>> [3]. According to [1, 2], in these tests of aeronautical and space-rocket devices, pulsed A- (or repetitive pulsed D-), an intermediate B- and prolonged C- (or shortened long [C.sup.*]-) current component of artificial lightning can be used. Moreover, combinations of these current components which follow one after the other in time and differ greatly in their amplitudes (from hundreds of kA to tens of A) and flowing times (from hundreds of microseconds to one thousand milliseconds), can be different [1, 2]. Most often, in the practice of testing individual elements of such aircraft as civil and military aircraft for lightning, the following combinations of these lightning current components are used [1-4]: A-, B- and C- components, A-, B- and [C.sup.*]- components and D-, B- and [C.sup.*]- components.

For indicated lightning current components, such an important parameter for the electrothermal loading in the high-current discharge circuit of the powerful GCL of the test objects of aviation and rocket and space technology, in accordance with the requirements of [1, 2], as the integral of their action JL, does not numerically exceed 2 x [10.sup.6] J/Q [+ or -] 20 %. We note that it is the value of this integral [J.sub.L] that determines the value of the thermal energy released on the test element of an object. Therefore, the value of [J.sub.L] often determines the electrothermal lightning capacity of such an object. In addition, when performing full-scale tests according to the requirements of the international standard IEC 62305-1: 2010 [5] of electric power facilities for the lightning strength of the value of the action integral JL of the aperiodic current pulse of 10 [micro]s/350 [micro]s of artificial lightning generated by the developed and created in 2012 at the Department No. 4 of electromagnetic tests of the Research & Design Institute <<Molniya>> of the NTU <<KhPI>> with powerful GCL [6], for the I level of their protection against lightning should be 10 x [10.sup.6] J/Q [+ or -] 35 %.

With the electrical current loading of the tested objects, it is necessary to register and monitor the ATP of the lightning current component used in the online mode. Typically, similar electrotechnological procedures are performed using measuring means, such as high-voltage high-current measuring shunts (HHMSs) with coaxial cable communication lines operating in a matched wave mode [3, 4], and digital storage oscilloscopes (DSO). As a rule, HHMSs are special non-standardized measuring tools, which are not produced by industry due to their insignificant quantitative need and absence from businessmen for such products of commercial interest. Therefore, domestic high-voltage electrical engineers, together with engineers-metrologists, have to solve their own engineering and technical problems for their development and production with subsequent state metrological certification.

1. The state of the engineering task. In [7], the design and technical characteristics of a measuring coaxial shunt of the fflK-300 type were described to determine the ATP pulses of artificial lightning current generated in high-current discharge circuits of the geological and technical measures in accordance with the requirements of normative documents [1, 2]. The structure of this shunt includes a manganin measuring disk with a thickness [h.sub.s] [approximately equal to] 0.3 mm with an external diameter [D.sub.se] [approximately equal to] 80 mm, which determines the impulse resistance of the shunt, which is approximately [R.sub.S] [approximately equal to] 0.185 m[OHM] [+ or -] 1% [3, 7]. The practice of operating the fflK-300 shunt in laboratory conditions showed its insufficient electrothermal and electrodynamic stability in the high-current discharge circuit of the GCL which reproduces the pulsed current [i.sub.L](t) of artificial lightning on the active-inductive load ([R.sub.l] [approximately equal to] 0.1 [OHM], [L.sub.l] [approximately equal to] 1 [micro]H) with an action integral equal to about [J.sub.L] [approximately equal to] 2 x [10.sup.6] J/Q [+ or -] 20% [1, 2]. After approximately 100 specified high-current discharges of GCL for the test load and a measuring shunt of the fflK-300 type, the latter loses its metrological characteristics and becomes unsuitable for its further use. According to [5], according to [5], for the aperiodic current pulse of 15 [micro]s/315 [micro]s of an artificial lightning with an amplitude [I.sub.mL] [approximately equal to] 184 kA ([J.sub.L] [approximately equal to] 7.88 x [10.sup.6] J/Q) according to [5], the shunt was destroyed by an internal impulse gas-dynamic pressure in a few hundred atmospheres due to the electric explosion (sublimation) of a part of the material of its thin measuring manganin disk [8]. As we see, when using high-voltage pulse technology with discharge currents of capacitor batteries GCL in hundreds of kA to the choice of the design of the corresponding measuring shunt, higher requirements for its electrothermal lightning resistance should be presented.

In [9], the design of a shunt shunt for the measurement of pulsed currents of microsecond duration with amplitude of up to 75 kA was presented. As a high-resistance measuring element in this shunt structure, parallel-connected straight-line segments of nichrome wire were placed along the circumference between two massive coaxial cylindrical electrodes of the shunt internal brass and outer duralumin [9]. The ends of each piece of nichrome wire placed parallel to the longitudinal axis of the shunt were soldered to two parallel massive brass disks, between which was a cylindrical ceramic insulator. With a shunt sensitivity of about 350 mV/kA, it allowed reliably to measure only large microsecond pulses the currents of a high-voltage electrophysical installation (amplitude not exceeding 75 kA) and transmit without distortion the current pulse front up to 0.6 [micro]s [9].

The goal of the paper is the development and creation at the Research & Design Institute <<Molniya>> of the NTU <<KhPI>> of a coaxial disk shunt of the IIIK-300M2 type which makes it possible to reliably measure the ATP of current pulses of artificial lightning in wide amplitude and time ranges with an action integral up to 15 x [10.sup.6] J/Q.

2. Problem definition. The operational experience of the high-voltage high-current fflK-300 type high-current measuring shunt accumulated in the Department No. 4 of electromagnetic testing of the Research & Design Institute <<Molniya>> of the NTU <<KhPI>> demonstrates that, taking into account the state of the high-voltage impulse technique of the actual task of metrological support of tests on [1, 2, 5] of domestic aviation and rocket and space technology, as well as electric power facilities for lightning in this shunt construction improvement must be subject to: first, a thin measuring manganin disk; secondly, the insulation between the massive internal brass and massive outer brass cylindrical electrodes. These two positions are the <<weak links>> in the design of the fflK-300 measuring shunt with its intended application as part of measuring instruments designed to implement technical tasks in accordance with the stringent requirements of [1, 2, 5].

It is required to rationally select the geometry and material of the measuring disk, as well as the insulation between the main brass electrodes in the measuring coaxial shunt, which, after the improvement, has acquired the name IIIK-300M2, is required within the applied engineering and technical approach. In addition, after the modernization of the measuring coaxial disk shunt, it is necessary to perform its practical testing and testing of the operability in the high-current discharge circuit of the current high-power high-voltage GCL according to [3].

3. Calculation evaluation of some parameters of the measuring coaxial disk shunt of the IIIK-300M2 type. As the material of the measuring disk of a coaxial shunt of the type IIIK-300M2, we chose the stainless steel 12X18H10T of domestic production widely used in engineering and everyday life [10]. The average thickness [h.sub.sm] of the measuring disk wall of the investigated high-current high-voltage coaxial shunt of the IIIK-300M2 type in the adiabatic mode of its operation on the basis of the known laws of electrical and thermal physics can be estimated from the following relationship:

[h.sub.sm] [approximately equal to] [([pi][D.sub.sm]).sup.-1][[([J.sub.L][[rho].sub.s])/([c.sub.s][DELTA][T.sub.S][d.sub.s])].sup.1/2], (1)

where [D.sub.sm] [approximately equal to] [D.sub.se]/2; [[rho].sub.s], [c.sub.s], [d.sub.s] are the specific electrical resistance, specific heat and density of the disk material at ambient temperature [T.sub.0] equal to room temperature 20 [degrees]C, respectively; [DELTA]Ts = ([T.sub.s] - [T.sub.0]) is the ermissible short-term overheating of the material of the shunt disk with its current temperature [T.sub.s] caused by the current flowing through it.

For design reasons, we assume that the outer diameter of the measuring steel disk in a IIIK-300M2 shunt is Dse-80 mm, and its internal diameter is [D.sub.si] [approximately equal to] 10 mm. Then, from (1) with [D.sub.sm] [approximately equal to] 40 mm, [J.sub.L] [approximately equal to] 15 x [10.sup.6] J/Q, AT-100 [degrees]C and the initial data known for [10] for 12X18H10T stainless steel ([[rho].sub.s] [approximately equal to] 72,5 x [10.sup.-8] [OHM] x m; [c.sub.s] [approximately equal to] 462 J/(kg x [degrees]C); [d.sub.s] [approximately equal to] 7900 kg/[m.sup.3]), we obtain that the radial averaged wall thickness of the measuring steel disk will be numerically equal to [h.sub.sm] [approximately equal to] 1.4 mm. Taking into account a certain reserve in thickness [h.sub.sm] and taking into account our very limited technological possibilities in the selection of materials, we choose the thickness of the wall of the measuring disk of stainless steel 12X18H10T equal to [h.sub.sm] [approximately equal to] 2 mm.

Note that in (1) for a shunt of the IIIK-300M2 type studied, the value of the short-term superheating [DELTA]Ts of the material of the measuring disk, occurring during the time of the current [i.sub.L](t) no more than 1000 ms in practically adiabatic mode, is limited by the type of solid insulation used to separate it from main brass electrode shunt. When using fluoroplastic insulation, the value of overheating [DELTA]Ts for reliable operation of IIIK-300M2 shunt in the GCL composition should not be more than 100 [degrees]C [3, 4]. At [DELTA][T.sub.s] [approximately equal to] 50 [degrees]C and the initial data taken above for the integral of the action [J.sub.L] of the pulsed lightning current, the geometric, electrical, and thermophysical characteristics of the steel shunt disk from (1), it follows that the [h.sub.sm] thickness of the disk is exactly about 2 mm.

The active resistance [R.sub.S0] of the measuring steel disk of the coaxial shunt IIIK-300M2 in the quasi-stationary mode, which practically corresponds to the regime of DC current flowing through it, can be approximated by the following formula [11] :

[R.sub.S0] [approximately equal to] 0.5 [([pi][h.sub.sm]).sup.-1][[rho].sub.s] ln([D.sub.se]/[D.sub.Si]). (2)

From (2) at [h.sub.sm] [approximately equal to] 2 mm, [[rho].sub.s] [approximately equal to] 72.5 x [10.sup.-8] [OHM] x m, [D.sub.se] [approximately equal to] 80 mm and [D.sub.si] [approximately equal to] 10 mm it follows that the sought value of RS0 is approximately equal to 0.12 m[OHM]. Measurement of the shunt of the IIIK-300M2 shunt type, almost equal to the [R.sub.s0] value, carried out by metrologists in a highly stable scheme of 19 A a DC generator showed that in this experimental case [R.sub.s0] [approximately equal to] 0.094 m[OHM]. It can be seen that the difference between the calculated and experimental data for [R.sub.s0] in our case does not exceed 22 %.

4. Practical implementation of the measuring coaxial disk shunt type MK-300M2. Fig. 1, 2, respectively, are a general view and a schematic arrangement of a measuring coaxial disk shunt of the type IIIK-300M2. The weight of this measuring shunt is about 3.2 kg, and its overall dimensions do not exceed 90x95 mm.

From the data in Fig. 2, it can be seen that a measuring steel disk 5 of thickness [h.sub.sm] [approximately equal to] 2 mm is tightly clamped between its massive disks 6 and 7 with a thickness of 10 mm, made of a sheet of fluoroplastic insulation. Between the massive brass cylindrical electrodes 1 and 4 of the shunt through which the measured current pulse [i.sub.L](t) of artificial lightning flows from the GCL capacitors, insulating sleeves 2 and 3 with a thickness of 3 mm are installed, also made of fluoroplastic insulation.

These bushings significantly increase the electrical strength of the insulating gaps between the live parts of the high-voltage high-current shunt of the IIIK-300M2 type, which positively affects the reliability of its functioning as part of a powerful GCL. The increased electrodynamic resistance of the shunt under investigation is provided by a massive pressure brass ring 13 with a thickness of 7 mm, a brass shroud disk 8 with a thickness of 5 mm and steel screws of fixation 12 in quantity of 8 pieces evenly distributed along the outer circular perimeter of the massive brass electrode 4 of the shunt.

A measuring coaxial disk shunt of the type IIIK-300M2 is connected in the rupture of a high-current high-voltage discharge circuit of a powerful GCL of one or another version [3, 5]. Moreover, the inner cylindrical brass electrode 1 with diameter of 29 mm of the shunt is connected by means of the bolted joint elements 14 to the potential part of the high-current discharge circuit of the GCL, and its outer cylindrical brass electrode 4 with a diameter 80 mm with the help of the 15 bolt connection elements--to the grounded part of the discharge circuit of the GCL (usually to the metal grounded collector of the high-power capacitor bank of the generator).

5. Results of experimental approbation of a measuring coaxial disk shunt of IIIK-300M2 type in a high-current circuit of high-voltage GCL. Fig. 3 shows an oscillogram of the pulsed A--component of artificial lightning current obtained by means of a measuring coaxial disk shunt of the type IIIK-300M2, included in the discharge circuit of a powerful GCL [3] reproducing according to the requirements of normative documents [1, 2] on the active-inductive load ([R.sub.l] [approximately equal to] 0.1 [OHM], [L.sub.l] [approximately equal to] 1.5 [micro]H) pulses of artificial lightning current.

In the course of experimental studies of the behavior of the improved design and characteristics of a fflK300M2 shunt in the discharge circuit GCL [3] whose capacitor bank, when forming the one shown in Fig. 3 components of the lightning current were charged to a constant voltage [U.sub.cA] [approximately equal to] -29.7 kV, it was found that its impulse resistance RS takes a numerical value equal to about [R.sub.s] [approximately equal to] 0.08 m[OHM] [+ or -] 1%. This experimental [R.sub.S] value under flow conditions along the measuring steel shunt disk shown in Fig. 3 pulsed current [i.sub.L](t) of artificial lightning differs from the active resistance [R.sub.S0] [approximately equal to] 0.094 m[OHM] of the shunt in question by no more than 15% in direct current. It should be noted that the indicated values of the active resistances [R.sub.S] and [R.sub.S0] are in good agreement with the results of previous studies of transient electromagnetic processes and the penetration depths of the pulsed electromagnetic field in conducting non-magnetic media on the sections of the first three half-waves of the decaying sinusoidal current pulse acting on them [4]. Due to the peculiarities of the distribution in the metal of the measuring disk of the shunt of the pulsed electromagnetic field from the measured pulsed current [i.sub.L](t) of the simulated lightning, its impulse resistance RS will always be less than the active resistance of the [R.sub.S0] disk measured at constant current [4].

It is known that the value of the impulse active resistance [R.sub.S] of the shunt measuring disk in the coordinated mode of connecting its coaxial cable communication line to the DSO determines its conversion coefficient [S.sub.S] having the dimension A/B and calculated by the ratio [S.sub.S],[approximately equal to] 2/[R.sub.S]. In this case, the value of the [S.sub.S] parameter is numerically equal to the current flowing through the shunt disk when a voltage of 1 V is applied to its input. In this connection, the ATP, measured with a coaxial IIIK-300M2 shunt of the pulse current [i.sub.L](t) of artificial lightning in the discharge chains of a powerful GCL will be determined by the following relationship:

[i.sub.L](t) [approximately equal to] [S.sub.S][U.sub.LO] (t), (3)

where [U.sub.LO](t) is the pulse voltage recorded by means of a measuring shunt on the screen of the DSO.

Taking into account the presented results, we find that the conversion coefficient SS of the measuring shunt of the IIIK-300M2 type for the recording mode according to them [1, 2] of the A- and D- components of the pulsed current of artificial lightning, and also according to [5] 10 [micro]s/350 [micro]s will be [S.sub.SA] [approximately equal to] 2/[R.sub.s] [approximately equal to] 25 x [10.sup.3] A/B. When using a shunt made at the end of a coaxial cable line of a shunt made on the basis of an PK 75-7-11 radio frequency cable with a 75-[OHM] impedance matching voltage divider [3, 7], the [S.sub.S] conversion coefficient of the investigated shunt-type shunt of the IIIK-300M2 type in mode of registration of the intermediate B-, long C- and shortened long [C.sup.*]- component of the artificial lightning current will be equal to [S.sub.SC] [approximately equal to] 1/[R.sub.s] [approximately equal to] 12,5 x [10.sup.3] A/V. This MVD is implemented with two output coaxial connectors 1:1 (for [S.sub.SA]) and 1:2 (for SSC) based on three 110 [OHM] resistors and placed in a separate shielded housing [3, 7].

Fig. 4 shows the oscillogram of the shortened longtime [C.sup.*]- component of the current of artificial lightning in a high-current discharge circuit of the GCL [3] which follows in time immediately after the pulsed A- current component of the lightning and simultaneously fixed on the DSO screen by means of a measuring coaxial disk shunt of type IIIK-300M2. We will point out that in the conducted experiments the DSO Tektronix TDS 1012 series were used in a buried measuring bin and remote from the GCL discharge circuits at a distance of approximately 70 m.

The charging voltage of the negative polarity of the capacitor bank GCL [3] which forms on the activeinductive load [R.sub.l] [approximately equal to] 0.1 [OHM]; [L.sub.l] [approximately equal to] 1.5 [micro]H) the shortened [C.sup.*] current component of the simulated lightning applied to the data in Fig. 4 was [mathematical expression not reproducible]. Note that the ones shown in Fig. 3 and 4 ATPs of the pulsed A- and shortened long-time [C.sup.*]- current component of a lightning simulated in the laboratory conditions correspond to the current requirements of normative documents [1, 2].

Conclusions.

1. The developed and created at the Department No. 4 of electromagnetic tests of the Research & Design Institute <<Molniya>> of the NTU <<KhPI>> measuring coaxial disk shunt of type IIIK-300M2 developed and created allows for its direct placement in a high-current high-voltage discharge circuit of a powerful GCL by means of one additional shielded coaxial cable communication line up to 70 m and a few located in remote from the GCL buried deep shielded bunker DSO in an agreed mode of their operation simultaneously and repeatedly measured on the active-inductive load of the tested object, the main components of artificial lightning current with normalized ATPs in accordance with the requirements of US regulations SAE ARP 5412: 2013 and SAE ARP 5416: 2013 with their amplitude up to [+ or -]220 kA and the action integral up to 2.4 x [10.sup.6] J/Q.

2. The measuring coaxial disk shunt of the IIIK-300M2 type is capable of repeatedly recording on the activeinductive load and transmitting in a coordinated mode along the coaxial cable communication line to the DSO the aperiodic pulses of a time current of 10 [micro]s/350 [micro]s of a short stroke of an artificial lightning generated in a high-current high-voltage discharge circuit of a powerful GCL with standardized ATPs according to the requirements of the International Standard IEC 62305-1: 2010 with their amplitude up to [+ or -]220 kA and the action integral up to 13.5 x [10.sup.6] J/[OHM].

3. The high-current experiments on a high-power high-voltage GCL were carried out in June 2017 at the Experimental and Test Site of the Research & Design Institute <<Molniya>> of the NTU <<KhPI>> in accordance with the requirements of the US regulations SAE ARP 5412: 2013 and SAE ARP 5416: 2013 of the measuring coaxial disk shunt type IIIK-300M2 which passed the state metrological certification at the state enterprise <<Kharkivstandartmetrologiya>> (certificate of conformity No. 06/0206 of 19.07.2017).

10.20998/2074-272X.2017.5.07.

Please Note: Illustration(s) are not available due to copyright restrictions.

Received 09.08.2017

REFERENCES

[1.] SAE ARP 5412: 2013. Aircraft Lightning Environment and Ralated Test Waveforms. SAE Aerospace. USA, 2013. pp. 1-56.

[2.] SAE ARP 5416: 2013. Aircraft Lightning Test Methods. SAE Aerospace. USA, 2013.--pp. 1-145.

[3.] Baranov M.I., Koliushko G.M., Kravchenko V.I., Nedzel'skii O.S., Dnyshchenko V.N. A Current Generator of the Artificial Lightning for Full-Scale Tests of Engineering Objects. Instruments and Experimental Technique, 2008, no. 3, pp. 401405. doi: 10.1134/s0020441208030123.

[4.] Baranov M.I. Izbrannye voprosy elektrofiziki. Tom 2, Kn. 2: Teoriia elektrofizicheskikh effektov i zadach [Selected topics of Electrophysics. Vol.2, Book 2. A theory of electrophysical effects and tasks]. Kharkiv, Tochka Publ., 2010. 407 p. (Rus).

[5.] IEC 62305-1: 2010 <<Protection against lightning. Part 1: General principles>>. Geneva, IEC Publ., 2010.

[6.] Baranov M.I., Koliushko G.M., Kravchenko V.I., Rudakov S.V. A generator of aperiodic current pulses of artificial lightning with a rationed temporal form of 10 [micro]s/350 [micro]s with an amplitude of [+ or -](100-200) kA. Instruments and Experimental Techniques, 2015, vol. 58, no. 6, pp. 745-750. doi: 10.1134/s0020441215060032.

[7.] Dnyshchenko V.N., Eremeev V.O., Nedzelsky O.S., Ponudzhaeva E.G. SC-300 measuring shunt for determining the amplitude-time parameters of the simulated lightning current pulse. Bulletin of NTU <<KhPI>>. series: Technique and electrophysics of high voltage, 2007, no. 20. pp. 75-79. (Rus).

[8.] Baranov M.I., Kniaziev V.V., Rudakov S.V. Calculation and experimental estimation of results of electro-thermal action of rationed by the international standard IEC 62305-1-2010 impulse current of short blow of artificial lightning on the thinwalled coverage from stainless steel. Electrical engineering & electromechanics, 2017, no. 1, pp. 31-38. (Rus). doi: 10.20998/2074-272X.2017.1.06.

[9.] Donets S.E., Ledenev V.V., Litvinenko V.V. Rod shunt to measure strong currents of microsecond duration. Bulletin of NTU <<KhPI>>. series: Technique and electrophysics of high voltage, 2008, no. 44. pp. 34-44. (Rus).

[10.] Available at: http://prom.ua/p19700265-pischevayanerzhaveyuschaya-stal.html (accessed 12 June 2014). (Rus).

[11.] Baranov M.I., Belyi I.V., Khimenko L.T. Equivalent electrical parameters of coaxial systems of various shapes with a homogeneous azimuthal magnetic field in the gap. Theoretical electrical engineering, 1976, no. 20, pp. 67-74. (Rus).

M.I. Baranov (1), Doctor of Technical science, Chief Researcher, V.V. Kniaziev (1), Candidate of Technical science, senior Research scientist, S.V. Rudakov (2), Candidate of Technical science, Associate Professor,

(1) Scientific-&-Research Planning-&-Design Institute <<Molniya>>, National Technical University <<Kharkiv Polytechnic Institute>>, 47, Shevchenko Str., Kharkiv, 61013, Ukraine, phone +380 57 7076841, e-mail: baranovmi@kpi.kharkov.ua, knyaz2@i.ua

(2) National University of Civil Protection of Ukraine, 94, Chernyshevska Str., Kharkiv, 61023, Ukraine, phone +380 57 7073438, e-mail: serg_73@i.ua

Caption: Fig. 1. General view of a coaxial shunt type IIIK-300M2 designed to measure on the screens of the DSO in an agreed mode of operation of its coaxial cable communication line of powerful current pulses of artificial lightning in a high-current discharge circuit of a high-voltage GCL with an integral of their action up to 15 x [10.sup.6] J/Q

Caption: Fig. 2. Elements of the structure of a coaxial disk shunt of the IIIK-300M2 type in its longitudinal axial section (1--massive internal cylindrical electrode, 2,3--insulating sleeves, 4--massive outer cylindrical electrode, 5--high-resistance steel measuring disk, 6,7--massive insulation disks, 8--a shroud disk, 9,10,12--fastening screws, 11--CP-75 output coaxial connector, 13--massive clamping ring, 14, 15--respectively input (potential) and output (earthed) bolted shunt connecting elements to high-current discharge circuit of the GCL)

Caption: Fig. 3. The oscillogram of the pulsed A- component of the artificial lightning current with normalized ATPs in the high-current discharge circuit of the GCL [3] obtained with the help of a measuring coaxial disk shunt of the type IIIK-300M2 ([I.sub.mA1] [approximately equal to] 200 kA; [t.sub.mA1] [approximately equal to] 38 [micro]s; [J.sub.A] [approximately equal to] 2.39 x [10.sup.6] J/Q; [U.sub.cA] [approximately equal to] -29.7 kV; [S.sub.SA] [approximately equal to] 25 x [10.sup.3] A/V; scale on the vertical--125 kA/cell; scale on the horizontal--50 [micro]s/cell)

Caption: Fig. 4. The oscillogram of the shortened long [C.sup.*]- component of the artificial lightning current with normalized ATPs in the discharge circuit of the GCL [3] obtained simultaneously with the current A- component flowing before it with the aid of a measuring coaxial disk shunt of the type IIIK-300M2 [mathematical expression not reproducible]; scale on the vertical--625 A/cell; scale on the horizontal--10 ms/cell)
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Author:Baranov, M.I.; Kniaziev, V.V.; Rudakov, S.V.
Publication:Electrical Engineering & Electromechanics
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Date:Sep 1, 2017
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