Development of High-Voltage Vacuum Circuit Breakers in China

856
IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 35, NO. 4, AUGUST 2007
Development of High-Voltage Vacuum
Circuit Breakers in China
Zhiyuan Liu, Member, IEEE, Jimei Wang, Senior Member, IEEE, Shixin Xiu, Zhongyi Wang,
Shun Yuan, Li Jin, Heming Zhou, and Ren Yang
Abstract—This paper introduces a research work on the development of high-voltage (HV) vacuum circuit breakers (VCBs) in
China from its start point 1989 to 2006. In this period, a 126-kV
two breaks VCB prototype and a 126-kV single break VCB prototype were developed. A latest 252-kV single break interrupter
prototype is introduced. Five HV VCBs technologies are discussed,
which include HV vacuum insulation, high current interrupting
technology with long contact gaps, increasing nominal current,
operating mechanism characteristics, and contact bouncing damping. In vacuum insulation, adding a metal ring at electrode back
can decrease breakdown possibilities in the gap between the electrode back and main shield. Surface melting layer of contact material could have influence on voltage withstanding capability of a
vacuum gap. For interrupting high current with long contact gaps,
strong axial magnetic field (AMF) is needed for a better vacuum
arc control. Therefore, a single coil AMF electrode is introduced.
Heat radiators are effective to increase nominal current of VCBs.
Thermal analysis can help to give appropriate design parameters.
There is an optimum opening characteristic that is helpful to improve the interrupting performance of VCBs. Permanent magnet
operating mechanism and spring-type operating mechanism are
suitable for HV VCBs. Contact bouncing in HV VCBs can be
damped by installing contact spring and bellows on stationary end
of VCBs.
Index Terms—High voltage (HV), vacuum arc, vacuum circuit
breakers (VCBs), vacuum interrupter (VI).
I. I NTRODUCTION
R
ESEARCH work on vacuum switch and vacuum arc in
China started from 1958 [1]. Vacuum circuit breaker
(VCB) is popular in medium voltage breaker market in China.
As an example, VCB occupied 98.85% of 12-kV circuit breaker
market in China in 2004 [2]. VCBs are also stepping into higher
voltage field in China.
In 1989, a research team was set up to develop highvoltage (HV) VCB in China. This team included Xi’an Jiaotong
University, Beijing Switchgear Factory, and Beijing Dongfang
Vacuum Tube Factory. A two-break 126-kV/1250-A/31.5-kA
VCB prototype was developed by this team [3]. In 2003, a
new research team was set up to develop a 126-kV single
Manuscript received July 14, 2006; revised February 5, 2007.
Z. Liu, J. Wang, S. Xiu, Z. Wang, S. Yuan, and L. Jin are with the State
Key Laboratory of Electrical Insulation and Power Equipment, Xi’an Jiaotong
University, Xi’an 710049, China (e-mail: liuzy@mail.xjtu.edu.cn).
H. Zhou is with Zhejiang Wenling Ziguang Electrical Apparatus Company,
Zhejiang 317507, China.
R. Yang is with Shaanxi Electric Power Research Institute, Xi’an 710054,
China.
Color versions of one or more of the figures in this paper are available online
at http://ieeexplore.ieee.org.
Digital Object Identifier 10.1109/TPS.2007.896929
break VCB, with the cooperation of Xi’an Jiaotong University,
Shaanxi Baoguang Vacuum Device Company Ltd., Zhejiang
Wenling Ziguang Electrical Apparatus Company, and Xi’an
SHIKY High Voltage Electric Company Ltd. This work was
driven by the effects of high global warming potential of
SF6 gas shown in Kyoto Conference, and this work was also
based on the earlier experience on HV VCB. A prototype of
126-kV/2000-A/40-kA single-break VCB is completed, and it
is under further research tests in order to pass type test. Most
recently, the research team proposed an idea to develop a singlebreak 252-kV VCB.
There are many technologies that support HV VCB, such
as the following. 1) High-voltage insulation technology, which
includes vacuum insulation and external insulation of vacuum
interrupter (VI). 2) Interrupting technology with long contact
gaps. Generally, HV vacuum insulation requirements lead to
long contact gaps where vacuum arcs are more difficult to be
controlled by a magnetic field. To interrupt high short circuit
current successfully with long contact gaps, axial magnetic
field (AMF) technology is preferred. 3) Nominal current increasing technology. High-voltage circuit breaker needs high
nominal current level. Also, heat conduction path of HV VCB
is long that is an obstacle to increase the nominal current level.
4) Operating mechanism characteristic technology. The opening and closing characteristics provided by operating mechanism should cooperate with the vacuum arc characteristics
in obtaining an optimum performance. 5) Contact bouncing
damping technology. This phenomenon is particularly obvious
in HV VCB, because the closing velocity and contact stroke in
HV VCBs are higher than that of medium voltage ones.
This paper introduces the research and development work
on HV VCB done in China from 1989 to 2006 with the five
mentioned aspects.
II. H IGH -V OLTAGE V ACUUM C IRCUIT B REAKERS
A. 126-kV Two-Break VCB Prototype
A 126-kV/1250-A/31.5-kA two-break VCB prototype is
shown in Fig. 1 [1]. Two VIs are in series. There is a capacitor
connected with each VI in parallel. The external insulation
of the two VIs is by SF6 gas. The height of the prototype is
2650 mm. Spring-type mechanism is used. Its average opening
velocity is 2.4 m/s, and the average closing velocity is 1.8 m/s.
A 72.5-kV VI for the 126-kV two-break VCB is shown in
Fig. 2 [3]. Its contact gap is 40 mm. It includes AMF electrode, main shield, auxiliary shields, end shields, ceramic envelope, conducting rods, moving contact bellows, and stationary
0093-3813/$25.00 © 2007 IEEE
LIU et al.: DEVELOPMENT OF HIGH-VOLTAGE VACUUM CIRCUIT BREAKERS IN CHINA
Fig. 1.
126-kV two-break VCB prototype [1].
857
Fig. 3. 126-kV single-break VCB prototype.
TABLE I
MAIN TECHNICAL OBJECTIVES OF 126-kV VCB
Fig. 2.
72.5-kV VI [3].
contact bellows for damping of shocks in closing operations. Its
total height is 876 mm, and the distance from upper flange to
lower flange is 640 mm. The height of main shield is 260 mm.
B. 126-kV Single-Break VCB Prototype
A 126-kV/2000-A/40-kA single-break VCB prototype is
shown in Fig. 3. Two kinds of operating mechanisms are
used: one is spring type and the other is permanent magnet
type. Its main technical objectives are shown in Table I. This
prototype has passed some research tests such as dielectric
withstanding tests, LC discharging current interrupting tests,
and temperature rise tests. It needs further tests. After that, it
can be sent for a type test.
C. 252-kV Single-Break VI
A comparison of 252-kV single-break VI prototype, 126-kV
single-break VI prototype, and 12-kV VI is shown in Fig. 4. The
length of the 252-kV prototype is 1300 mm from upper flange
to lower flange. Its diameter is 260 mm. Its electrode diameter
is 140 mm, and the contact gap is 80 mm. There are five
858
IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 35, NO. 4, AUGUST 2007
TABLE II
IMPULSE VOLTAGE WITHSTAND TEST RESULTS OF 72.5-kV VI [4]
Fig. 4. Comparison of 252-, 126-, and 12-kV VIs.
shields and four sections of glass envelopes. The weight of this
prototype is 70 kg. As a first step, its main technical objectives
were set as rated nominal current 3150 A and rated short circuit
breaking current 40 kA. The first prototype of 252-kV singlebreak VI is finished in April 2006, and there are no test results
so far, such as dielectric withstanding tests, temperature rise
tests, and short circuit current interrupting tests, which will be
reported with further research work.
Fig. 5. Improving of insulation strength of the gap between electrodes and
main shield [4]. (a) Method I. (b) Method II.
III. HV VCB T ECHNOLOGIES
maximum electric strength of main shield of 1.0 × 105 V/m
and the maximum electric strength of inner surface of ceramic
of 0.6 × 105 V/m were much lower. Some actions should be
taken to increase the insulation strength of the weak gap.
There are two methods to increase the insulation strength of
the gap between the electrodes and the main shield. One is to
decrease the electric strength on the surface of the electrode
back by adding a radius R on the electrode back, as shown
in Fig. 5(a). When R is 1.3 times of electrode radius, the
maximum electric strength decreased by 10%. The other is to
add a ring near the electrode back, as shown in Fig. 5(b). By
this method, the maximum electric strength decreased by 30%.
Therefore, the latter method was adopted for validation, and
the test results are shown in Table III. Compared with Table II,
the insulation level was improved as the breakdown number
decreased from 2 to 0 at the contact gap of 40 mm and voltage
peak of 250 kV. Thus, adding a ring on the electrode back was
also adopted in 126-kV and 252-kV single-break VIs.
Contact material is an important influence factor on voltage
withstanding capability. It is found that there is a surface
A. HV Vacuum Insulation
In HV VIs, there are many possible breakdown gaps that
include contact gap, gap between electrodes and shields, gap
between different shields, inner surface of insulator, and external surface of insulator. The most possible breakdown gap
is not certainly the contact gap. For example, impulse voltage
withstanding test (1.2 × 50 µs) results in developing the
72.5-kV VI prototype are given in Table II [4]. After the test, the
VI was opened, and it was found that the breakdown occurred
in the gap between electrodes and main shield. Because the
contact gap is 40 mm and the minimum distance between the
electrodes and main shields is 30 mm in that prototype, electric
strength on the surface of electrode back was stronger than that
on the electrode surface. It was known from the electric field
analysis that the maximum electric strength on the electrode
surface was 3.9 × 105 V/m with an applied voltage of 1 kV
and that the maximum electric strength on surface of electrode
back was 4.1 × 105 V/m with the same applied voltage. The
TABLE III
IMPULSE VOLTAGE WITHSTAND TEST RESULTS OF
72.5-kV IMPROVED VI [4]
LIU et al.: DEVELOPMENT OF HIGH-VOLTAGE VACUUM CIRCUIT BREAKERS IN CHINA
Fig. 6. SEM photo of CuCr40 contact material after DC arc conditioning and
power frequency voltage conditioning. Surface melting layer is on the left part
of the photo. The wide right part is CuCr40 contact material, where the black
particles are Cr and the gray flat part is copper.
Fig. 7. SEM photo of CuCr40Fe contact material after DC arc conditioning
and power frequency voltage conditioning. The surface melting layer is on the
top part of the photo. The wide bottom part is CuCr40Fe contact material. There
are some holes and cracks between the surface melting layer and base material.
859
Fig. 8. Arc current and arc voltage waveform with a contact gap of
60 mm . Ch1—arc current 7.9-kA rms/div; Ch2—arc voltage 100 V/div. Time:
10 ms/div.
Fig. 9. Relationship between arc voltage and contact gap [4]. Arc current is
30-kA rms.
B. Interrupting Technology With Long Gap
melting layer on the contact surface after arc conditioning and
voltage conditioning. Fig. 6 is a SEM photo of CuCr40 contact
material after DC arc conditioning and power frequency voltage
conditioning. There is a surface melting layer that is ∼ 10 µm
on the left part of the photo. The wide right part of the photo is
CuCr40 contact material, where the black particles are Cr and
the gray flat part is copper. Fig. 7 is a SEM photo of CuCr40Fe
contact material after the same DC arc conditioning and power
frequency voltage conditioning. The surface melting layer is on
top part of the photo. The wide bottom part is CuCr40Fe contact
material. There are some holes and cracks between the surface
melting layer and base material CuCr40Fe in Fig. 7. This is
different from that in Fig. 6 where the surface layer links to the
base material seamlessly. The power frequency withstanding
voltage test results showed that the power frequency withstanding voltage of the VI with CuCr40 contact material was
100 kV at the contact gap of 5 mm, while CuCr40Fe was
90 kV at the same situation. Surface melting layer of contact
material is considered as a contributor to the voltage withstanding capacity of the contact gap of a VI.
Generally, there is a long contact gap in a HV VI, which
brings difficulties for vacuum arc control. This is obviously
shown in arc voltage. A vacuum arc voltage oscillogram, with
current of 10-kA rms and contact gap of 60 mm, is shown
in Fig. 8. There is a high arc voltage noise, which indicates
that the vacuum arc is unstable in a long contact gap. Arc
voltage increases with the increase of contact gap, as shown
in Fig. 9, where the current is 30-kA rms [4]. When the contact
gap increased from 10 to 40 mm, the maximum “stable” arc
voltage increased from 42 to 54 V. Critical current, with which
arc voltage noise appears, decreased with an increase of contact
gap, and the critical current increases with a stronger AMF, as
shown in Fig. 10 [4]. With a strong AMF, the critical current
decreased from 30 to 20 kA, with a contact gap increased from
30 to 40 mm. With a medium AMF, the critical current decreased from 20 to 5 kA, with an increase of contact gap from
10 to 40 mm. Also, with a weak AMF, the critical current was
low, and the contact gap has little influence on it. With a fixed
contact gap, such as 40 mm, a strong AMF can significantly
increase the critical current from around 5 to 20 kA.
860
Fig. 10. Relationship between current with which arc voltage noise appears
and contact gap [4].
Main shield potential is also an indicator of vacuum arc
characteristics that is unstable in long contact gaps, as shown
in Fig. 11 [4]. Here, channel A was the main shield potential,
and channel B was the arc voltage. Contact gap was 40 mm.
Fig. 11(a) shows the arc current at 2-kA rms. It is shown that
arc voltage was smooth, and there was only a small ripple near
the peak of main shield potential. Fig. 11(b) shows the arc
current at 30-kA rms. It is shown that there is high noise in both
arc voltage and main shield potential. This occurred only with
40-mm contact gap and arc current greater than 10-kA rms in
the tests, while there was no such phenomena with a contact
gap of 10 mm.
Contact gap has a strong influence on ion current collected
by the main shield too, but it is modified by the AMF. As
shown in Fig. 12 [4], curves 1, 2, 4 have a contact gap of
40 mm, and curves 3, 5, 6 have a contact gap of 10 mm. Curves
1, 2, 4 correspond to weak AMF, medium AMF, and strong
AMF, respectively. Similarly, it does for curves 3, 5, 6. As
shown in Fig. 12, the ion current collected by the main shield
with a contact gap of 40 mm is higher than that of the contact
gap of 10 mm, but it is also modified by the AMF. With stronger
AMF, the ion current decreases. Thus, curve 4 that is with
strong AMF in contact gap of 40 mm is lower than curve 3
that is with weak AMF in contact gap of 10 mm.
From the mentioned vacuum arc characteristics in long contact gaps, it is shown that vacuum arcs tend to be unstable
and strong AMF is needed to control the vacuum arc. To meet
the requirements, a single coil electrode is developed, which
is helpful in generating stronger AMF, as shown in Fig. 13.
Current flows through conducting rod, then it goes one round
in coil, and it enters contact plate. By passing through the arc,
the current flows through counterpart contact plate, coil, and
conducting rod.
This AMF electrode was used in the 126-kV single-break
VI prototype. With the single coil electrodes, a 45-kA rms LC
discharging current was interrupted in a 126-kV single-break
VI with a contact diameter of 100 mm and contact gap of
60 mm, as shown in Fig. 14, where channel 1 is arc current
and channel 2 is arc voltage.
IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 35, NO. 4, AUGUST 2007
AMF distribution with the single coil AMF electrode was
analyzed by using a commercial electromagnetic field finite element method (FEM) software. In the FEM analysis, the current was 40-kA rms, frequency—50 Hz, contact
diameter—100 mm, contact gap—60 mm, contact material—
CuCr50 (conductivity 1.8 × 107 S/m). Arc was treated as a
cylinder conductor with the same diameter that of the contact
plate, and arc conductivity was set as 2000 S/m. The analysis
results were as follows.
Its axial magnetic flux density distribution on middle plane
of contact gap at current peak was shown in Fig. 15. The
maximum axial magnetic flux density was at contact center, and
it was 0.356 T with a contact gap of 60 mm. This corresponds
to 6.3 mT/kA.
At current zero, the AMF distribution on the middle plane
was shown in Fig. 16. There was a peak at the contact center.
The maximum axial magnetic flux density at current zero was
0.084 T, which is 23.6% of that at current peak.
On contact surface, the AMF was stronger. As shown in
Fig. 17, there was a strong AMF ring on the contact surface
at current peak. The maximum axial magnetic flux density was
0.801 T. This corresponds to 14.2 mT/kA.
The AMF distribution on the contact surface at current zero is
shown in Fig. 18. The peak was also at the contact center. The
maximum axial magnetic flux density on the contact surface
at current zero was 0.301 T, which was 37.6% of that at
current peak.
This single coil electrode was also used in the 252-kV singlebreak VI prototype, as shown in Fig. 4. In the 252-kV VI,
contact diameter was 140 mm and contact gap was 80 mm.
The maximum axial magnetic flux density was 3.5 mT/kA on
the middle plane of contact gap and 8.6 mT/kA on the contact
surface.
C. Nominal Current Increasing Technology
In HV VCB, high nominal current is needed, but it is hard
to reach. In vacuum, the only effective heat transfer approach is
heat conduction. Convection and radiation cannot help. However, the HV VCB generally has long heat conduction path,
which is difficult to increase the nominal current. In 126-kV
single-break VCB, heat radiators were installed on the head
and waist of each pole to increase the nominal current level,
as shown in Fig. 19. As a result, a steady temperature rise of the
126-kV single-break VCB prototype was 30 K at inlet terminal
and outlet terminal with a nominal current of 2000-A rms by
temperature rise measurement.
Thermal analysis can help to give appropriate VCB design
parameters. In the thermal analysis, the convection coefficients
and radiation coefficients were obtained by a commercial computational fluid dynamic software, and the coefficients were
input into a thermal analysis software to calculate temperature distribution. Fig. 20 shows the thermal analysis results
of a pole of the 126-kV single-break VCB prototype with
a nominal current of 2000 A. The current is from an inlet
terminal to a stationary conductor rod of a VI, and then, the
current goes through a stationary contact and a moving contact.
Finally, it goes through a moving conductor rod to a mechanical
LIU et al.: DEVELOPMENT OF HIGH-VOLTAGE VACUUM CIRCUIT BREAKERS IN CHINA
861
Fig. 11. Main shield potential and arc voltage at contact gap of 40 mm [4]. A—main shield potential, 20 V/div; B—arc voltage, 30 V/div. (a) Arc current 2 kA.
(b) Arc current 30 kA.
Fig. 12. Relationship between ion current collected by main shield and arc
current with contact gaps 10 and 40 mm [4]. Curves 1, 2, 4—contact gap of
40 mm with weak, medium, and strong AMF. Curves 3, 5, 6—contact gap of
10 mm with weak, medium, and strong AMF.
supporting conductor and reaches the outlet terminal. Cooling
fins were installed, as shown in the top part and bottom part
of Fig. 20. In Fig. 20, the temperature at the inlet terminal
was about 40 ◦ C, and the temperature at the outlet terminal
was about 36 ◦ C. As ambient temperature was set as 10 ◦ C
in the analysis, which was the same as that of temperature
measurements were done, the temperature rise at the inlet
terminal was about 30 K, and the temperature rise at the outlet
terminal was about 26 K. The simulation results were close to
the measured temperature rise of 30 K.
D. Operating Mechanism Characteristic Technology
There is a contact gap range where short circuit current
interrupting performance of a VI is higher. Short circuit current
interrupting tests by synthetic circuit were done at various
maximum contact gaps that were set from 1 to 13 mm. The
tested VI was with a slot-type AMF electrode, and its contact
diameter was 60 mm. Maximum interrupting capacity was
Fig. 13. Single coil AMF electrode.
measured at each maximum contact gap. It was found that there
is a maximum interrupting capacity with contact gaps from 3 to
6 mm, as shown in Fig. 21 [5]. This indicates that there is an
optimum contact gap range with which the interrupting capacity
is higher.
The above results were supported by another short circuit
current interrupting method on synthetic circuit. In these tests,
maximum contact gap was the same, and it was set as 14 mm.
Arcing time (opening angle of moving contact) was controlled;
therefore, the contact gap at current zero can be known with
the help of opening velocity. Thus, the maximum interrupting
capacity can be measured at each contact gap at current zero.
Test results are shown in Fig. 22 [5]. In the tests, the VIs were
also with a slot-type AMF electrode. Velocities of the moving
contact were the same in all tests. It is shown in curve 1 of
Fig. 22, where contact diameter is 45 mm, that there is a maximum interrupting capacity with a contact gap from 3 to 5 mm.
Similarly, curve 2 and curve 3, where the contact diameter is
60 and 75 mm, respectively, indicate that there is a maximum
862
IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 35, NO. 4, AUGUST 2007
Fig. 17. Axial magnetic flux density distribution on contact surface at current
peak with single coil electrode. Current: 40-kA rms, contact diameter: 100 mm,
contact gap: 60 mm.
Fig. 14. Short circuit current interruption with single coil electrode AMF VI
in an LC discharging circuit. Ch1—arc current 15.7-kA rms/div; Ch2—arc
voltage 500 V/div. Time: 10 ms/div, contact gap: 60 mm, contact diameter:
100 mm.
Fig. 18. Axial magnetic flux density distribution on contact surface at current
zero with single coil electrode. Current: 40-kA rms, contact diameter: 100 mm,
contact gap: 60 mm.
Fig. 15. Axial magnetic flux density distribution on middle plane of contact
gap at current peak with single coil electrode. Current: 40-kA rms, contact
diameter: 100 mm, contact gap: 60 mm.
Fig. 19.
Fig. 16. Axial magnetic flux density distribution on middle plane of contact
gap at current zero with single coil electrode. Current: 40-kA rms, contact
diameter: 100 mm, contact gap: 60 mm.
interrupting capacity with a contact gap from 4 to 6 mm. These
test results also support that there is an optimum contact gap
range with which the interrupting capacity is higher.
Increasing nominal current by heat radiators.
Based on the knowledge of optimum contact gap range, optimum opening characteristics of the moving contact provided
by the operating mechanism are suggested to reach a maximum
interrupting capacity of VCB, as shown in Fig. 23 [6]. They are
as follows: 1) Initial opening velocity should be as fast as possible to reach L1 that is the start point of the optimum gap range;
2) velocity in optimum contact gap range L1 to L2 is slower,
LIU et al.: DEVELOPMENT OF HIGH-VOLTAGE VACUUM CIRCUIT BREAKERS IN CHINA
Fig. 20.
Thermal analysis by simulation 126-kV single-break VCB prototype.
Fig. 21. Relationship between interrupting capacity and various maximum
contact gaps (contact diameter of 60 mm) [5].
Fig. 22. Relationship between interrupting capacity and various contact gaps
at current zero [5]. Contact diameter: 1–45 mm; 2–60 mm; 3–75 mm.
in which the vacuum arc extinguishes at current zero; 3) with
damping of damper, the contact stops at the final position Lm.
Permanent magnetic actuator for the 126-kV single-break
VCB is shown in Fig. 24. Its main components include moving
iron core, static iron core, closing coil, opening coil, opening
spring, operating rod, and permanent magnets. Closing and
opening state is kept by permanent magnets. Opening spring
863
Fig. 23. Optimum opening characteristics of operating mechanism [6].
Fig. 24. Permanent magnet operating mechanism for 126-kV singlebreak VCB.
energy is stored in closing operation. When an opening signal
is received, the moving iron core is pushed by the opening
spring to open position. Its contact stroke is 60 mm. Its average
opening velocity is 3.5 m/s, and its average closing velocity is
1.4 m/s.
Spring-type mechanism is another good candidate for HV
VCB. Mechanical dynamic simulation can help give a reasonable design according to the optimum closing and opening
curve of the operating mechanism. Fig. 25 shows a simulation
of an opening process of the HV VCB by a commercial
software. Displacement characteristics of the moving contact
can be obtained, as shown in Fig. 25, which can be adjusted
until it meets the optimum opening curve. Mechanical design
parameters can also be varied as will to analyze its influence
of velocity characteristics. Fig. 26 shows the influence of
contact spring force on the initial opening velocity of the
moving contact in HV VCB simulations. The initial opening
velocity increased with an increase of contact spring force, but
it saturated at about 1500 N in the simulation.
E. Contact Bouncing Damping Technology
Contact bouncing in the closing operation of HV VCB is
high, as the impact force of the moving contact is very high
864
IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 35, NO. 4, AUGUST 2007
Fig. 25. Opening characteristics simulation of spring-type mechanism of HV VCBs. The mechanism includes stationary contact, moving contact, contact spring,
insulating rod, link rods, and opening spring. The right part is the simulated displacement of moving contact.
Fig. 26. Relationship between contact spring force and initial opening velocity in HV VCB simulations.
Fig. 28. Velocity and displacement of moving contact with installation of contact spring and bellows on stationary end of VCB [5]. Upper curve—velocity;
lower curve—displacement.
IV. C ONCLUSION
High-voltage VCB is a technology integration, including HV
vacuum insulation, long gap interruption of high short circuit
current, high nominal current, and mechanical technology, etc.
With these technologies, 126-kV two-break VCB and 126-kV
single-break VCB prototypes were developed. 252-kV VCB is
the next objective in developing the HV VCB in China.
R EFERENCES
Fig. 27. Contact bouncing damping technologies in HV VCBs [5].
due to a high closing velocity and a long contact stroke. This
could damage contacts, conducting rod, and insulator envelope.
A high contact bouncing could also damage contacts by severe
arc erosion.
To decrease the contact bouncing in HV VCB, bellows are
installed not only with a moving contact but also with a stationary contact, which are shown as moving contact bellows and
stationary contact bellows in Fig. 27 [5]. In addition, contact
spring is installed on stationary end. In this way, the contact
bouncing is minimized, as shown in Fig. 28 [5], where the upper
curve is the velocity of moving contacts and the lower curve is
its displacement.
[1] J. Wang and J. Wang, “Review of theoretical research in vacuum arc and
their applications in China,” in Proc. 19th Int. Symp. Discharges and Elect.
Insulation Vacuum, Xi’an, China, 2000, pp. 133–149.
[2] J. Li, “Medium voltage vacuum circuit breaker market situation in the
world,” High Voltage Switchgear Review, no. 3, pp. 21–23, Mar. 2006.
(in Chinese).
[3] J. Wang and S. Yuan, High Capacity Vacuum Switch Theory and Product Development. Xi’an, China: Xi’an Jiaotong Univ. Publishing House,
2001, pp. 349–355. (in Chinese).
[4] L. Jin, “Study of high voltage and high interrupting capacity vacuum interrupter,” Ph.D. dissertation, Dept. Elect. Eng., Xi’an Jiaotong Univ., Xi’an,
China, 1997. (in Chinese).
[5] S. Yuan, “Effects of vacuum circuit breaker operating mechanism on its
interrupting capacity and development of 63 kV and 110 kV vacuum circuit
breaker,” Ph.D. dissertation, Dept. Elect. Eng., Xi’an Jiaotong Univ., Xi’an,
China, 1993. (in Chinese).
[6] S. Yuan, Y. Wang, and J. Wang, “Optimal moving curve of electrode to
interrupt a short current for vacuum circuit breaker,” in Proc. 2nd Int. Conf.
ECAAA, Xi’an, China, 1993, pp. 248–252.
LIU et al.: DEVELOPMENT OF HIGH-VOLTAGE VACUUM CIRCUIT BREAKERS IN CHINA
Zhiyuan Liu (M’01) was born in Shenyang, China,
in 1971. He received the B.S. and M.S. degrees
in electrical engineering from Shenyang University
of Technology, Liaoning, China, in 1994 and 1997,
respectively, and the Ph.D. degree in electrical engineering from Xi’an Jiaotong University, Xi’an,
China, in 2001.
From 2001 to 2002, he was with the General
Electric Company Research and Development Center (Shanghai), Shanghai, China. Since 2003, he has
been a Lecturer in the Department of Electrical Engineering, Xi’an Jiaotong University. He has published more than 40 technical
papers in China and abroad. He is primarily involved in the research and
development of high-voltage vacuum circuit breakers.
Jimei Wang (SM’98) was born in Hangzhou,
Zhejiang Province, China, in 1922. He received the
B.S. degree in electrical engineering from Shanghai
Utopia University, Shanghai, China, in 1946.
He is a Professor at Xi’an Jiaotong University,
Xi’an, China, and he has been a Ph.D. Supervisor authorized by the Academic Commission of
State Council of China since 1978. He is a Pioneer
Researcher on vacuum arc theory and organized a
research group on vacuum arc theory and their applications in China in 1958. In 1964, he developed
the first vacuum switch in China. He has published 15 monographs and
410 technical papers in China and abroad.
Prof. Wang is a Senior Member of Chinese Electrical Engineering Society and a Senior Member of Chinese Electro-technical Society. He was the
Chairman of the first International Conference on Electric Contacts, Arcs,
Apparatus and their Applications in Xi’an, China, in 1989. He was a member
of the Permanent International Scientific Committee (PISC) of the International
Symposium on Discharges and Electrical Insulation in Vacuum (ISDEIV)
and a Scientific Member of International Conference on Electric Fuses and
their Applications. In 2006, he received the Walter P. Dyke Award from the
International Symposium on Discharges and Electrical Insulation in Vacuum
(ISDEIV).
Shixin Xiu was born in Lingyuan, Liaoning
Province, China, in 1967. He received the B.S. and
M.S. degrees from Heibei Institute of Technology,
Tianjin, China, in 1990 and 1993, respectively, and
the Ph.D. degree in electrical engineering from Xi’an
Jiaotong University, Xi’an, China, in 1998.
Since 2001, he has been an Associate Professor in the Department of Electrical Engineering,
Xi’an Jiaotong University. His research interest includes vacuum switchgear, vacuum arc, and contact
materials.
865
Zhongyi Wang was born in Shanghai, China, in
1956. She received the B.S., M.S., and Ph.D.
degrees in electrical engineering from Xi’an Jiaotong
University, Xi’an, China, in 1982, 1987, and 1997,
respectively.
Since 1982, she has been with the Department
of Electrical Engineering, Xi’an Jiaotong University,
where she is currently an Associate Professor. Her research interests include vacuum arcs, vacuum interrupters, and numerical analysis of electric magnetic
field.
Shun Yuan was born in Shen Yang, China, in 1963.
He received the Ph.D. degree in electrical engineering from Xi’an Jiaotong University, Xi’an, China,
in 1993.
He is currently a Department Director of Northeast
China Bureau of SERC in Shenyang, China, and a
member of State Key Laboratory of Electrical insulation and Power Equipment, Xi’an Jiaotong University, Xi’an, China. He is also a part-time Professor in
the Department of Electrical Engineering, Shenyang
University of Technology, Shenyang, China. His research interests include vacuum circuit breaker, power system reliability and
electric power system overvoltage.
Dr. Yuan is a member of IEC TC99.
Li Jin, photograph and biography not available at the time of publication.
Heming Zhou, photograph and biography not available at the time of
publication.
Ren Yang was born in Xi’an, China, in 1970.
He received the M.S. degree in electrical engineering from Xi’an Jiaotong University, Xi’an, China,
in 2004.
Since 1992, he has been with Shaanxi Electric
Power Research Institute, Xi’an, China. He is currently a Senior Engineer. His research interests include high-voltage SF6 circuit breaker and vacuum
circuit breaker.