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TRANSMITTER H.V. & RF INTERLOCKS

DIMITRIS BALTADOROSDIMITRIS BALTADOROS

Electrical Engineer NTUAElectrical Engineer NTUA

22/3/2006

IASA

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TRANSMITTER

The high-power CW (continuous-wave) source, at 2380 MHz, for the IASA 10-MeV Linac is based on the

VARIAN type VKS-8270 multi-cavity 450 KW klystron. The high-level DC power conditioning for the klystron

uses a high-voltage transformer-rectifier (RECTIFIER) and variable-voltage transformer (VVT), originally

designed and built in USA to operate from 60 Hz power, with ratings altered to accommodate the locally

available 50Hz primary power. To operate from 50Hz AC without iron core saturation the input voltage

reduced by factor 50/60, from 13.8KV line-line, 3-phase reduced to 11.5KV line-line, 3-phase maximun

input voltage. The local nominal H.V. power, available at IASA, is 20KV line-line, 3-phase , therefore, a

step down transformer used to supply the 11.5KV line-line, 3-phase to the input of VVT .

The VVT will have a variable output of 5.5 KV – 11.5 KV line-line, 3-phase. This variable AC High Voltage

gives a RECTIFIER output of 28 – 54 KV DC. The KLYSTRON, therefore, will have a maximum output of

300 KW.

Other features include a new electronic THYRATRON CROWBAR system desined and built at CERN

especially for IASA, a high speed primary - power disconnect with VACUUM CONTACTORS (V.C.) and a

completely new H.V. & RF INTERLOCK SYSTEM designed and built at IASA.

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HIGH VOLTAGE STEP-DOWN TRANSFORMER 20KV-11.5KV / 50Hz

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CIRCUIT BREAKERS (CB) & VACUUM CONTACTORS

VACUUM

CONTACTORS

CB2 HALF CYCLE DISCONNECTION

TIME

(10ms)• MANUALLY

CLOSE

• 220V TRIGGER

FOR OPENING

• 3-5 CYCLES OPENING

TIME (100ms)

HIGH SPEED

DRIVER

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VARIABLE VOLTAGE TRANSFORMER (VVT) & RECTIFIER

RECTIFIERINPUT: 5.5 – 11.5 KV AC

OUTPUT: 28 - 54 KV DC

V.V.TINPUT: 11.5KV AC

OUTPUT: 5.5 - 11.5KV AC

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CB1

T120KV/11.5K

V

V.C.

T2V.V.T.

(∆-Υ)RECTIFIER

ELECTRONICBOX

ALARMPANEL

V.V.T. CONTROL PANELAND INTERLOCKS

CROWBAR INTERLOCKS

AND MONITORTHYRATRONCROWBAR

MAGNET P.S.

FILAMENT P.S.

Body Current

Collector Current

10 Ω

40 ΩAWG 30

DISCHARGE RELAY 2

DISCHARGE RELAY 1

CB2

UPS

20KV

3φ

50Hz

KLYSTRONKLYSTRON

TEST CROWBARTEST CROWBAR

FILTER CAPACITOR

5.55.5--11.5 KV11.5 KV

TRANSMITTER BLOCK DIAGRAM

11.5 KV

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H.V. RESISTORS AND DISCHARGE RELAY 1 (D.R.1)

H.V. RESISTORS USED FOR CURRENT LIMITATION. DISCHARGE RELAY 1 USED TO DISCHARGE THE 3 µF CAPACITOR INSIDE THE RECTIFIER AND MAKES THE H.V. CAGE SAFE.

10 Ω

40 Ω

DISCHARGE RELAY 1

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THYRATRON CROWBAR

THE THYRATRON CROWBAR ,DESINED AND BUILT AT CERN, HAS THE

FOLLOWING FEATURES:

•MULTIGAP DOUBLE-ENDED THYRATRON

• INTERNAL TRIGGER TRANSFORMER 1V/1A

• VERY FAST OPERATION (~2 µs)

• FULL INTERLOCK SIGNALS FOR RELIABLE OPERATION (INCLUDED IN H.V.

INTERLOCK SYSTEM)

CURRENT THROUGH

THYRATRON

SHORT CIRCUIT CURRENT

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ELECTRONIC BOX

THE ELECTRONIC BOX , BUILT AT IASA, CONSISTS OF THE FOLLOWING PARTS:

• TRIGGER TRANSORMER 1V/A FOR THE VACUUM CONTACTORS

• SHUNT RESISTORS FOR THE MONITORING OF BODY AND COLLECTOR CURRENTS

• THYRISTOR CIRCUIT FOR EXTERNAL TRIGGER OF VACUUM CONTACTORS

• VERY HIGH CURRENT DIODE, 5600 A PEAK, FOR THE SHORT CIRCUIT CURRENT

VACUUM CONTACTORS TRIGGER TRANSFORMER

HIGH CURRENT

DIODESHUNT RESISTOR

THYRISTOR CIRCUIT

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MAGNET FILAMENT & ION PUMP POWER SUPPLIES

MAGNET POWER SUPPLY

FILAMENT POWER SUPPLY

ION PUMP POWER SUPPLY &

INTERLOCKS

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ALARM PANEL

•TRIGGERS THE CB2 ,WITH 220V FROM UPS.

• OVER TEMPERATURE AND EARTH TRIP INTERLOCKS OF

H.V. TRANSFORMER.

• INTERCONNECTION WITH THE H.V. INTERLOCK SYSTEM

• AUDIBLE ALARM ON FAULT

• LAMP INDICATORS

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H.V. & RF INTERLOCK SYSTEMS

A COMPLETELY NEW INTERLOCK SYSTEMS DESIGNED AND BUILT AT IASA. THE DEVELOPMENT OF THE INTERLOCK SYSTEMS MANAGE TO MATCH THE RELIABLE RELAY TECHNOLOGY WITH

THE POWERFULL AND FLEXIBLE PLC TECHNOLOGY. ALL THE ELECTRONIC DEVICES AS

• VVT CONTROL PANEL & INTERLOCKS

• CORWBAR INTERLOCKS PANEL

• KLYSTRON ION PUMP INTERLOCKS

• H.V. STATUS PANEL

DESIGNED AND DEVELOPED AT IASA, FOR THE H.V. INTERLOCK SYSTEM, WITH CAPABILITIES OF FULL MONITORING (DIGITAL & ANALOG SIGNALS) AND ALSO CONTROL OF THE H.V.

OUTPUT.

SOME OF THE H.V. INTERLOCKS IMPLEMENTED WITH PLC. THE SIEMENS PLC S7-300 SELECTED AS THE OPTIMAL, CAUSE OF ITS FAST CPU AND THE FLEXIBILITY ON EXTENSION.

FOR MONITORING AND CONTROL WE USE THE SIEMENS WINCC SCADA SYSTEM.

OTHER FEATURES OF THE H.V. INTERLOCKS SYSTEMS ARE:

• RED-GREEN INDICATORS SHOW THE STATUS OF ALL INTERLOCKS

•LATCH ON FAULT (so we can check the fault)

• RESET INTERLOCKS FUNCTION

• RESET VVT AND PANIC BUTTON

• AUTO RESET ON FAULT (so we will have min. output on next H.V. ON)

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CB2

ALARM PANELTRANSFORMER

INTERLOCKS

OVERTEMPERATUREEARTH TRIP

V.V.T. CONTROL PANEL & INTERLOCKS

INTERLOCKS:V.V.T.: VVT READY

VVT DOOROVER TEMPERATURE

RECTIFIER: OIL LEVELOVER TEMPERATUREOVER PRESSUREOVER CURRENT

CROWBAR INTERLOCKS PANEL

CROWBAR INTERLOCKS:OIL LEVEL

OVER TEMPERATUREHV&LV SIDE CONSUMPTION

HV&LV SIDE GRID1 CURRENT

BODY & COLLECTORCURRENT

INTERLOCKSOVER CURRENT

FILAMENT AND FOCUSINGINTERLOCKSOVER CURRENT

UNDER CURRENT

INTERLOCKS ON PLC

COOLING: (COLLECTOR, SOCKET,MAGNET, BODY)

VACUUM CONTACTORS DRIVER READY, CAGE DOOR, DISCHARGE STICK, WATER RESISTIVITY

220VUPS

220V220V

ENABLEENABLE

220V220V

TRIGGERTRIGGER

H.V. INTERLOCK SYSTEM BLOCK DIAGRAM

V.C.

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RF INTERLOCK SYSTEM BLOCK DIAGRAM

INTERLOCKS ON PLC

COOLING: RF WINDOWWAVE GUIDECIRCULATORRF LOADS

REFLECTED RF: KLYSTRONCIRCULATORLOADS

ARC DETECTOR & REFLECTED FAST INTERLOCKS

RFPIN DIODE

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H.V. SAFETY SHUTDOWN

INTERLOCKS FAULT

ARCIN

KLYSTRON

FAULT

SOURCE

CROWBAR~2 µs

CB2(100ms)

VACUUM CONTACTORS

(10ms)

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V.V.T. CONTROL PANEL AND INTERLOCKS

THIS DEVICE DESIGNED AND BUILT AT IASA TO PROCESS THE INTERLOCKS OF VVT AND RECTIFIER AND ALSO TO

CONTROL THE HIGH VOLTAGE OUTPUT

FEATURES• EASY RAISE-LOWER VVT

OUTPUT

•AUTO-MANUAL OPERATION OF VVT

•LOCAL-REMOTE FUNCTION

•LATCH ON FAULT

•AUTO RESET ON FAULT

• RESET VVT (PANIC BUTTON)

• LOCK RAISE-LOWER BUTTONS

• SET-POINT ADJUST THROUGH ELECTRONIC POTENTIOMETER

• DIGITAL DISPLAYS FOR MONITORING (VOLTAGE, CURRENT, SET-POINT)

• RED-GREEN STATUS INDICATORS

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CROWBAR INTERLOCKS PANEL

THE CROWBAR INTERLOCKS PANEL DESIGNED AND BUILT AT IASA TO PROCESS THE INTERLOCKS OF THE

THYRATRON CROWBAR.

FEATURES:

• OPTICAL RECEIVER FOR THE OPTICAL SIGNALS

• RED-GREEN STATUS INDICATORS

• PROGRAMMABLE SET POINTS FOR ANALOG INTERLOCKS

• RESET INTERLOCKS FUNCION

• TEST CROWBAR KEY SWITCH

• DIGITAL DISPLAYS FOR MONITORING

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SIEMENS PLC – SIMATIC S7-300

POWER SUPPLY

CPU I/O CARDS

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SIEMENS WINCC MONITORING AND CONTROL SYSTEM

Siemens SIMATIC WinCC SCADA (supervisory, control and data acquisition) package

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OPERATION OF KLYSTRON

After many years of inactivity the Klystron’s tube should be conditioned (cleaned).

The start up Beam Voltage of our power supply is 26 KV which is too high for the

procedure of conditioning of Klystron’s vacuum. We replaced the high power

step down transformer with a smaller one and we gradually apply 1 to 12 KV

Beam Voltage on Klystron, with full Interlock System functioning. The procedure

was slow cause the VacIon Current shouldn’t exceed the Interlock Set Point.

When we manage to have a Beam Current of 12 Kv with VacIon Current of under

20 µA, we connected again the High Power Step Down Transformer and we

continue with 26 KV to 50 KV . On this procedure many times the Interlock

System and the Crowbar was necessary to shut down the High Voltage, fast and

reliable, saving the Klystron from damage. Finally we achived to have a Beam

Voltage of 26 to 50 KV with Vac Ion Current below 20 µΑ.

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KLYSTRON’sKLYSTRON’s OPERATION PANELSOPERATION PANELS

CB’s INDICATORSCB’s INDICATORS

BODY&MAGNET BODY&MAGNET CURRENT

MAGNETMAGNETCURRENT

POWER SUPPLY POWER SUPPLY

VVT CONTROL PANELVVT CONTROL PANEL

FILAMENTFILAMENT

CROWBAR PANELCROWBAR PANELPOWER SUPPLYPOWER SUPPLY

VAC ION VAC ION

PLC’s PLC’s MONITORING MONITORING AND CONTROL

CONTROLLERCONTROLLER

AND CONTROL

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RF OUTPUT

P P (F) P P (R)(F) (R)

~~ KLYSTRONKLYSTRON

SPECTRUM SPECTRUM ANALYSERANALYSER POWER METERPOWER METER

RF RF GENERATOR

C2C2 C3C3GENERATOR

HIGH HIGH POWER POWER LOAD

C1C1LOAD60 dB 60 dB

Directional Directional CouplerCoupler

Filament Voltage : 10,5 VFilament Voltage : 10,5 V

Filament Current : 16 AFilament Current : 16 A

Magnet Current : 13 A

CABLE LOSSES:CABLE LOSSES:

C1+C2 = 3,95 dB C1+C2 = 3,95 dB

C2 = 2,40 dB Magnet Current : 13 AC2 = 2,40 dB

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We connected the instruments and with Klystron operating at minimum Beam Voltage (26KV) we slowly raise the RF in Power from 0 dBm to 14 dBm (max of the generator). At 10dBm we could see RF Output on the Spectrum Analyser. With 14 dBm input, we started slowly to raise the Beam Voltage. The measurements is shown on the following table:

VBeam Ic Ib Iion Pi PF PR Tcoll(KV) (A) (mA) (µΑ) (dBm) (dBm) (dBm) (C)

26 3,6 0,9 17 10 -15 -21 2130 4,6 1,0 17 10 - 8 -19 2235 5,6 1,1 17 14 0 -20 2538 6,1 1,2 18 14 2 -18 27 40 6,6 1,4 19 14 3,5 -20 2942 7,1 1,4 19 14 4,6 -19 30

Adding the cable losses and the attenuation of the coupler we fiAdding the cable losses and the attenuation of the coupler we find out nd out that the forward RF Power@42KV with 14dBm input is:that the forward RF Power@42KV with 14dBm input is:

PPff=4,6+60+2,4 = 67 =4,6+60+2,4 = 67 dBmdBm ~ 5KW~ 5KW

Gain = 4,6 + 60 + 3,95 Gain = 4,6 + 60 + 3,95 –– 14 = 54,55 dB 14 = 54,55 dB

These results are in accordance with the Varian’s Test Data. OurThese results are in accordance with the Varian’s Test Data. Our System is System is designed for a maximum Beam Voltage of 55KV. So According on thedesigned for a maximum Beam Voltage of 55KV. So According on theVarian’s Test Data, we will have a maximum saturated RF output oVarian’s Test Data, we will have a maximum saturated RF output of 335 f 335 KW@55KV ! KW@55KV !

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POWER METERPOWER METER

(REFLECTED)(REFLECTED)

RF SOURCERF SOURCE

@2380 MHz@2380 MHz

SPECTRUM SPECTRUM ANALYSERANALYSER

(FORWARD) (FORWARD)

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NEXT STEPS

• INSTALLATION OF THE ARC DETECTOR

• COMPLETE THE RF INTERLOCKS SYSTEM

• MAXIMUM RF OUTPUT ON LOAD

• MAXIMUM RF OUTPUT ON LOAD AFTER THE CIRCULATOR