test results of gyrotron power supply of kstar ech...
TRANSCRIPT
Test results of gyrotron power supply of KSTAR* ECH system
2004. 4. 24성균관대학교 (자연과학캠퍼스), 수원
배영순, 이한구, 정진현, 남궁원, 조무현포항공과대학교
박재안포스콘
2004년 80회 춘계물리학회
*Work supported by KBSI
Abstract• The KSTAR ECH system uses a CPI 84 GHz gyrotron which is designed with
the CPD (Collector-Potential-Depression) scheme. The gyrotron is capable of generating 500 kW RF power driven by 80-kV, 25-A electron beams. The gyrotron of the CPD type requires two power supplies, a cathode power supply (CPS) and a body power supply. The cathode power supply produces electron beams of 25 A. The cathode-body potential difference of 80 kV is maintained by the body power supply between the cathode and the gyrotron body. Therefore, the body power supply is called the acceleration power supply (APS). The nominal applied voltage and output current of the CPS are -80 kV and 30 A, respectively, and those of the APS are +100 kV and 100 mA, respectively. The gyrotron operation voltages are -56 kV at the cathode by the CPS and +24 kV at the body by the APS with respect to the collector at the ground potential. The system was tested with a resistor of 2.5 kΩ as a dummy load. We also confirmed that the fast switch-off prior to the high voltage crow-baring is capable of limiting the arc energy transfer less than 6 J using an in-house built arc-test zig. Conclusively, this test showed the power supply is properly designed and can be used for the gyrotron operation. In this paper, we present the detailed test skills and the test results.
KSTAR ECH system
Power monitoringmiterbend
Polarizermiterbends
AluminumTank load
Waveguideswitch
Arc detectormiterbends
miterbendWaveguideswitch
84-GHz, 500 kWGyrotron31.75-mm corrugated
waveguide
AluminumTank load Turbo
pump
A
Diamondwindow
5 kV DC break
Bellows
Launcher gear assembly
RF gate valveLauncher
input
L-box
Launcher assembly
•Transmission line components:1. Eight miter bends-One power monitoring miter bend-Three Regular miter bends-Two Arc detector miter bends-Two polarizer miter bends
2. Two pump-out tees3. Two waveguide switches4. Two bellows5. One 5 kV DC break6. One RF gate valve7. One Diamond window8. Two water loads
84-GHz, 500 kW gyrotron
• Specifications of Gyrotron (CPI VGB8084)
– Frequency: 84 GHz with 0.1 GHz bandwidth
– Power: 500 kW with duration of 2 sec pulse
– Gun Type: Diode-gun with cathode of 40.6 mm-radius
– Cavity mode: TE15,4,1 (31-kG focusing field)
– α = 1.4 (80 kV and 25 A)
– Collector Potential Depression
• Cathode-Collector Voltage: -56 kV
• Cathode-Body Voltage: -80 kV
• Beam Current: 25 A
– Heater voltage: 28 V, Heater current: 9 A
– Efficiency: 40 %
– RF output mode: TEM00 Gaussian mode with linear polarization
– Diamond window: edge-cooled single-disk with 2.0-inch (50.8 mm) aperture and 0.059-inch (1.5 mm) thickness
80 in
ches
(~ 2
met
ers)
Schematic circuit drawing of power supply
qCathode-Collector Power Supply (CPS)• -85 kV, 30 A • Pulse width: 10 µs ~ 10 sec• Crowbar switch system: Two ignitrons
with each trigger modules• Rise time: ~ 4 µs, Fall time: ~ 4 µs
qAcceleration Power Supply (APS: Cathod-Body Power Supply)• 100 kV, 100 mA• Pulse width: 10 µs ~ 10 sec• Rise time: ~ 4 µs, Fall time: ~ 4 µs
Configuration of power supply
Cathode
Body
CollectorVCB panel
Inverter stacks
Rectifier
Filter Deck
Cathode HVS APS
APS HVS
Heater PS
CPS 단독 테스트
APS
HVS
HVS
RG58To Oscilloscope(collector current)
30 kVClampMOV
2.2 kΩ
VC
iC
CT
Rise time: 16 µsec (for -30 kV)Fall time: 40 µsec Ripple: 1 kV / 8.8 kV *100 = 11 %Ripple 주기: 2.6 ms (379 Hz)(Inverter 주파수: ~ 800 Hz)
2.6 ms
VC
High Voltage ON/OFFON time: 2.4 secOFF time: 11 sec
500 µH
100 Ω
CPS
Cro
wba
r
APS 단독 테스트
APS
HVS
HVS
RG58To Oscilloscope(collector current)
30 kVClampMOV
2.2 kΩ
VB
iC
CT
VB
High Voltage ON/OFFON time: 3.4 secOFF time: 1sec
Rise time: 25 µsec (for + 26 kV)Fall time: 12 msec Overshoot:∆T ~ 460 µsec, ∆V ~ 1 kV
500 µH
100 Ω
∆T
∆V
CPS
Cro
wba
r
연동 운전 및 MOV test
Pearson CT (only measures fault current)
APS
HVS
HVS
RG58
RG58
To Oscilloscope(collector current)
30 kVClampMOV
2.2 kΩ
* APS 출력 증가시키며 VB 의 최대허용 전압 30 kV 유지되도록 MOV clamp기능 확인
VB
VC
To Oscilloscope(cathode currentshould be zero)
iB
iC
CTPearson CT
HV coaxial cable
Positive output for Electron flow
Direction of Arrow
HV coaxial cable
CPS
Cro
wba
r
Ch1: VC
Ch2: VB
Ch4: IC
Arc test
iFAULT
i FA
ULT
iFAULT
APS
HVS(OC set: 30 A)
HVS
RG58
Spark gapswitch
- 56 kV
+ 24 kV
To Oscilloscope
* Arc test는 crowbar test, clamp diode test, Pearson CT fault test 를 동시에 수반하는 테스트임.
test wire(sustaining energy: 6 J)
ClampDiode40 kV PIV
To Oscilloscope(arc current)
VB
VC
iC
CT
E/O Trans
Matrix Board
CTCT
HVS OFFHV OFF(Inverter OFF
VCB OFF)C
PS
Cro
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r
Crowbar OFFComp set: 20 A
VC = -56 kV,VB = +24 kV
VC = -30 kV,VB = +25 kV
Ch1: VC
Ch2: VB
Ch3: IARC
Gyrotron power supply electronics
collector currentmetering shunt(0.5 Ohm)
Pearson CT (only measures fault current)
Cathode
Collector
iC
iC
iC
iFAULT
i FA
ULT
iFAULT
BodyiB
APS
Body currentMetering shunt(100 Ohm)
E/O Trans
HVS
HVS
RG58
RG58
RG58
To OscilloscopeTo “Fast Interlock Signal Pre-processor (FISPP)”And To Oscilloscope
O/E Trans
30 kVClampMOV
* Arc current between the cathode and body will be a major fault current
ClampDiode40 kV PIV
Positive output for Electron flow
Direction of Arrow
CPS
HV floating
To “Fast Interlock Signal Pre-processor (FISPP)”
iC