A pulse transformer for a 10 MW klystron power supply
The design and test results of the Pulse Transformer (PT) for the klystron with a voltage of 120 kV, klystron current of 130 A and a pulse duration of 1.4 ms is presented. The PT design was realized with taking into account the following requirements: no edge effect on the secondary winding; no over...
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Національний науковий центр «Харківський фізико-технічний інститут» НАН України
2001
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| Zitieren: | A pulse transformer for a 10 MW klystron power supply / P.A. Bak, I.V. Kazarezov, V.V. Kobets, A.A. Korepanov, G.S. Krainov, V.I. Radchenko, V.S. Severilo, A.A. Tuvik // Вопросы атомной науки и техники. — 2001. — № 5. — С. 125-127. — Бібліогр.: 1 назв. — англ. |
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irk-123456789-790182015-03-25T03:02:36Z A pulse transformer for a 10 MW klystron power supply Bak, P.A. Kazarezov, I.V. Kobets, V.V. Korepanov, A.A. Krainov, G.S. Radchenko, V.I. Severilo, V.S. Tuvik, A.A. The design and test results of the Pulse Transformer (PT) for the klystron with a voltage of 120 kV, klystron current of 130 A and a pulse duration of 1.4 ms is presented. The PT design was realized with taking into account the following requirements: no edge effect on the secondary winding; no overvoltage along the secondary winding at the klystron breakdown; random high voltage breakdowns may occur only between metal parts, not on the windings; the sharp voltage edge applied to the primary winding should not cause a turn-to-turn overvoltage. 2001 Article A pulse transformer for a 10 MW klystron power supply / P.A. Bak, I.V. Kazarezov, V.V. Kobets, A.A. Korepanov, G.S. Krainov, V.I. Radchenko, V.S. Severilo, A.A. Tuvik // Вопросы атомной науки и техники. — 2001. — № 5. — С. 125-127. — Бібліогр.: 1 назв. — англ. 1562-6016 PACS number: 29.17.+w http://dspace.nbuv.gov.ua/handle/123456789/79018 en Вопросы атомной науки и техники Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
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Digital Library of Periodicals of National Academy of Sciences of Ukraine |
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DSpace DC |
| language |
English |
| description |
The design and test results of the Pulse Transformer (PT) for the klystron with a voltage of 120 kV, klystron current of 130 A and a pulse duration of 1.4 ms is presented. The PT design was realized with taking into account the following requirements: no edge effect on the secondary winding; no overvoltage along the secondary winding at the klystron breakdown; random high voltage breakdowns may occur only between metal parts, not on the windings; the sharp voltage edge applied to the primary winding should not cause a turn-to-turn overvoltage. |
| format |
Article |
| author |
Bak, P.A. Kazarezov, I.V. Kobets, V.V. Korepanov, A.A. Krainov, G.S. Radchenko, V.I. Severilo, V.S. Tuvik, A.A. |
| spellingShingle |
Bak, P.A. Kazarezov, I.V. Kobets, V.V. Korepanov, A.A. Krainov, G.S. Radchenko, V.I. Severilo, V.S. Tuvik, A.A. A pulse transformer for a 10 MW klystron power supply Вопросы атомной науки и техники |
| author_facet |
Bak, P.A. Kazarezov, I.V. Kobets, V.V. Korepanov, A.A. Krainov, G.S. Radchenko, V.I. Severilo, V.S. Tuvik, A.A. |
| author_sort |
Bak, P.A. |
| title |
A pulse transformer for a 10 MW klystron power supply |
| title_short |
A pulse transformer for a 10 MW klystron power supply |
| title_full |
A pulse transformer for a 10 MW klystron power supply |
| title_fullStr |
A pulse transformer for a 10 MW klystron power supply |
| title_full_unstemmed |
A pulse transformer for a 10 MW klystron power supply |
| title_sort |
pulse transformer for a 10 mw klystron power supply |
| publisher |
Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| publishDate |
2001 |
| url |
http://dspace.nbuv.gov.ua/handle/123456789/79018 |
| citation_txt |
A pulse transformer for a 10 MW klystron power supply / P.A. Bak, I.V. Kazarezov, V.V. Kobets, A.A. Korepanov, G.S. Krainov, V.I. Radchenko, V.S. Severilo, A.A. Tuvik // Вопросы атомной науки и техники. — 2001. — № 5. — С. 125-127. — Бібліогр.: 1 назв. — англ. |
| series |
Вопросы атомной науки и техники |
| work_keys_str_mv |
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| first_indexed |
2025-07-06T03:07:45Z |
| last_indexed |
2025-07-06T03:07:45Z |
| _version_ |
1836865306938572800 |
| fulltext |
A PULSE TRANSFORMER FOR A 10 MW KLYSTRON POWER SUPPLY
P.A. Bak, I.V. Kazarezov, V.V. Kobets, A.A. Korepanov, G.S. Krainov,
V.I. Radchenko, V.S. Severilo, A.A. Tuvik
Budker Institute of Nuclear Physics, SB RAS,
630090, Novosibirsk, Russia, Lavrentiev Ave., 11
e-mail: I.V.Kazarezov@inp.nsk.su
The design and test results of the Pulse Transformer (PT) for the klystron with a voltage of 120 kV, klystron current
of 130 A and a pulse duration of 1.4 ms is presented. The PT design was realized with taking into account the fol-
lowing requirements: no edge effect on the secondary winding; no overvoltage along the secondary winding at the
klystron breakdown; random high voltage breakdowns may occur only between metal parts, not on the windings; the
sharp voltage edge applied to the primary winding should not cause a turn-to-turn overvoltage.
PACS number: 29.17.+w
A superconducting linear electron positron collider
TESLA at an energy of several hundred GeV with an
operating frequency of 1.3 GHz (for powering RF struc-
tures) is being presently developed at DESY (Germany).
Within the frame of TTF program, the Budker Institute
of Nuclear Physics has been conducted R&D on the
modulator for power supply of a multibeam klystron
with the following output parameters of the klystron
voltage pulse [1]:
• Operating voltage 120 kV
• Klystron current 130 A
• The top duration pulse 1.4 ms
• Pulse rise and fall times does not exceed 100 µs
• Pulse repetition rate is up to 10 Hz.
As a first stage of the R&D it was suggested to carry
out the design and manufacture of the pulse transformer
(PT) stepping up the modulator pulse from 10 kV up to
120 kV to the klystron with pulse parameters described
above.
The development was carried out taking into account
a number of conditions as:
• the absence of large inhomogeneities of electric
fields (edge effects) in high voltage insulation;
• voltage gradients along the secondary winding in
the operating regimes and at breakdowns should not
differ too much;
• in the case of high voltage breakdown, the break-
down should proceed only on metal parts but not in
windings;
• applying fast rise time of voltage to the primary
winding should not cause excessive overvoltages
between turns of the primary winding;
• the absence of partial discharges in the high voltage
insulation of the secondary winding.
The first condition was realized for the charge of us-
ing the symmetric secondary winding with a middle
point under high potential;
the second one was met by the use of additional ca-
pacitances providing a uniform distribution of the volt-
age at a breakdown;
the third one was fulfilled with equipping the sec-
ondary winding with metal shields and inserting a
grounded shield between the primary and the secondary
windings.
the fourth one was realized by placing a capacitance
shield on the primary winding. This capacitance shield
provides a uniform voltage distribution along the prima-
ry winding at the pulse rise time.
the fifth – by impregnating coils of the secondary
winding with the epoxy compound according to tech-
nology eliminating partial discharges with further elec-
tric tests of each coil.
At the design stage, two types of dielectrics as oil or
SF-6 gas were considered as a basic insulation. By the
order of the customer, the choice was made in favor of
the mineral oil.
The schematic diagram of PT is given in Fig. 1. The
primary winding of PT is made of four connected in
parallel windings (W11, W12, W13, W14) connected
between each other in pairs.
Fig. 1. PT schematic diagram.
In order to decrease the interturn overvoltages, each
winding has a shield S2 providing the equalizing of
voltage gradients along the winding when applying the
voltage pulse with a fast rise or fall time. The PT sec-
ondary winding consists also of four windings connect-
ed in parallel (W21, W22, W23, W24) and connected in
pairs from the high voltage part. Such a connection en-
ables one to eliminate the influence of the edge on the
electric strength and thereby to decrease the gap and PT
leakage inductance.
Voltage distribution in the high voltage part of the
secondary winding is given in Fig. 2. Each secondary
winding is made of 15 coils. Shields inside each section
of the secondary winding and the grounded shield S1
ВОПРОСЫ АТОМНОЙ НАУКИ И ТЕХНИКИ. 2001. №5.
Серия: Ядерно-физические исследования (39), с. 125-127.
125
prevent the breakdown propagation directly between
turns of the primary and secondary windings. Though
such reinforcing elements on secondary sections result
in decreasing the electrical strength of the high voltage
gap, it increases the reliability of PT windings.
Shield S1
Y,mm
50
30
10
-10
-30
0 20 40 60 80 X,mm
120kV112kV104kV 112kV
Fig. 2. Electric field equipotentials in PT high volt-
age gap.
In order to prevent inadmissible overvoltages at sec-
tions of the secondary winding at breakdowns of trans-
former high voltage insulation or at klystron break-
downs, additional capacitances C6d...C15d are installed
in parallel to sections (Fig. 3). Fig. 3 shows the equiva-
lent circuit of the secondary winding for a calculation of
the voltage distribution process at sections if the break-
down occurs. At the initial moment, voltage is distribut-
ed homogeneously along the winding, i.e., the longitudi-
nal capacitances of sections C are equally charged and
voltage at transverse capacitances of sections Clt...C15t
increases linearly from Umax/15 up to its maximum
value Umax.
Fig. 3. Capacitive circuit for overvoltage calculation in
PT secondary winding.
C=334 pF, R=2 Ohm, L=2 µHn, R15=2.5 Ohm,
R14=3.3 Ohm, R13=R12=R11=R10=5 Ohm,
R9=R8=R7=R6=10 Ohm, C15d=4.8 nF,
C14d=4.25 nF, C13d=3.8 nF, C12d=3.1 nF,
C11d=2.5 nF, C10d=1.88 nF, C9d=1.41 nF,
C8d=0.94 nF, C7d=0.55 nF, C6d=0.22 nF,
С15t=43 pF, C14t=49.3 pF, C13t=55.5 pF,
C12t=61.7 pF, C11t=67.9 pF, C10t=74.1 pF,
C9t=80.3 pF, C8t=86.5 pF, C7t=92.7 pF, C6t=99 pF,
C5t=105.2 pF, C4t=111.4 pF, C3t=117.6 pF,
C2t=123.8 pF, C1t=130 pF.
The load breakdown is similar to the closing of the
switch S. The choice of shunting capacitances
C6d... C15d is determined by the condition of reducing
overvoltage at sections of the secondary winding at
breakdowns to the value of 1.5. Fig. 4 shows the poten-
tial distribution along the secondary winding (lower
curve) and overvoltage factor at winding sections with
correcting capacitances and without them for the case of
L=0 (see Fig. 3). An inductance L=2 mcH is the induc-
tance of the PT-load discharge circuit and an inductance
of sections of the secondary winding for capacitive cur-
rent. This inductance causes the oscillating process of
voltage redistribution at sections which causes an in-
crease in overvoltages at above mentioned correcting
capacitance up to ~1.2. For damping oscillations at
breakdown and for limiting energy released in the arc,
correcting capacitors are connected to sections through
resistors R6…R15.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
0,0
0,1
0,2
0,3
0,4
0,5
0,6
-1
0
1
2
3
4
P
ot
en
tia
l d
is
tri
bu
tio
n
al
on
g
w
in
di
ng
, r
el
. u
ni
ts
Section number
without correction
with correction
without correction
with correction
O
ve
rv
ol
ta
ge
on
s
ec
tio
ns
, r
el
. u
ni
ts
Fig. 4. Potential distribution along the secondary
winding and overvoltage factor at sections (with and
without correction).
For the efficient use of magnetic core, we introduced
its biasing through first sections of the secondary wind-
ings connected through the choke L1 to the bias circuit
power supply.
PT tank consists of two sections, the transformer and
klystron sections (Fig. 5). In the klystron section, there
are the klystron itself with high-voltage connector,
klystron filament transformer (4) and capacitive divider
(6). In order to provide time constant of the transformer
current set by technical requirements (pulse top drop at
the load of 50 Ohm and duration of 1 ms should not ex-
ceed 1%), the transformer core was selected to be the
50NP permalloy.
The design of the transformer is given in Fig. 5. The
basic component of PT is a magnetic core made of 8
subcores. Cores with the cross-section of 90x135 mm
are wound of the anisotropic steel 3408 with a phos-
phate insulating cover. In order to remove internal stress
and for improving magnetic parameters, prior to im-
pregnating the cores were annealed. After impregnation,
cores were cut in halves. Then these halves were glued
to each other through spacers into solid unit and then in-
ВОПРОСЫ АТОМНОЙ НАУКИ И ТЕХНИКИ. 2001. №5.
Серия: Ядерно-физические исследования (39), с. 126-127.
126
stalled into the casing of stainless steel and fixed there
with the epoxy compound. The total cross-section of the
magnetic core taking into account the filling factor is
920 cm2.
Fig. 5. PT design.
1 – transformer tank, 2 – pulse transformer, 3 –
core isolation choke, 4 – filament transformer, 5 –
current transformer, 6 – capacitive divider.
The length of the average magnetic line is 2.52 m.
The magnetic core weight is 1800 kg.
Primary windings are made of PSD wire with the
cross-section of 4x5.6 mm on the glass reinforced texto-
lite frame of a trapezoidal prism shape. The protection
shield is glued on the inner side of the primary winding
frame.
The secondary winding consisting of 4 windings
connected in parallel is located and fixed on the lower
beam of the magnetic core. The secondary winding is a
package of 30 sections assembled between 2 glass rein-
forced textolite bed plates. The secondary winding sec-
tion has 48 coils helically wound in two layers by the
PETVSD wire of 0.9x5 mm in cross-section.
The protecting shield made of stainless steel ribbon
of 0.5 mm in thickness connected to the coil end is fixed
along the inner contour of the lower layer of the coil.
The coil together with the shield is impregnated with the
epoxy compound.
At present, the manufacture of PT is almost complet-
ed and a cycle of tests envisaged by TR has been per-
formed.
The transformer was tested at voltage of 150 kV and
also in the regime of short circuit (8 hours at nominal
currents of the primary and secondary windings, and
bias choke and filament current). Now there is a prob-
lem concerning voltage distribution along secondary
winding during breakdowns at a voltage more then
150 kV.
The leakage inductance is Ls =320 µH.
Magnetic core parameters were measured. Accord-
ing to measurements in the nominal regime of opera-
tion, the total magnetizing current does not exceed 25 A
at a bias current of 5 A, that corresponds to TR.
REFERENCES
1. A.Akimov, A.Cherniackin, I.Kazarezov et. al.
Pulse Power Supply System for the 10 MW TESLA
Klystron (Performed under R&D Contract Attach-
ment 5 to Agreement RU/03533872/50095 for
DESY, Hamburg).
ВОПРОСЫ АТОМНОЙ НАУКИ И ТЕХНИКИ. 2001. №5.
Серия: Ядерно-физические исследования (39), с. 127-127.
127
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