Presentation on theme: "ISIS Electrical Engineering Group Mike Glover. ISIS Electrical Engineering Group Structure Group Leader ESSO 9 Staff DC Power 3 Staff Pulsed Power 4 Staff."— Presentation transcript:
ISIS Electrical Engineering Group Mike Glover
ISIS Electrical Engineering Group Structure Group Leader ESSO 9 Staff DC Power 3 Staff Pulsed Power 4 Staff PSU Development 5 Staff Controls & Electronics 3 Staff
ISIS Electrical Engineering Group Structure Mike Glover Group Leader ESSO Steve Stoneham Section Leader Steve Warner Office Manager Vacancy IT Manager Neil Kelly CAD Martin Dobbs CAD Vacancy CAD Austine Brine Contractor Paul Wade Contractor DC Power Vacancy Section Leader Geoff Martin Engineer Chris Gascoyne Technician Pulsed Power Adrian McFarland Section Leader Stephen Ruddle Engineer Vacancy Engineer John Bowsley Contractor PSU Development Jim Gray Section Leader Husam Al-Hakim Engineer Steve West Engineer Andy Kimber Engineer Martin Hughes Graduate Engineer Controls & Electronics Tim Carter Engineer Matt North Engineer Neil Farthing Contractor
Areas of Responsibility ISIS Synchrotron Power Supplies ISIS Extracted Proton Beam Line Power Supplies ISIS Neutron Beam Line Chopper Power Supplies Electrical Engineering of ISIS Control Systems for: Vacuum Systems Water Plant Systems Electrical Engineering of Neutron Instrument Beam Line Installations
ISIS Synchrotron Power Supplies Main Magnet “White Circuit” –14.4kV 650A DC 400A AC Injection & Extraction Septum –5kA & 10kA 50V DC Injection Dipole –50Hz 13kA 500µS Flat Top 100µS Rise Time Ring Steering & Trim Quadrupoles –4 Quadrant 150kA/S 250 Amp Programmable Fast Extraction Kicker Magnets –50Hz 40kV 5kA 500nS Flat Top 80nS Rise Time
Injection Septum Deflects the injected beam into the aperture of the injection dipole magnet and onto the foil 200kW 5000 Amps 40V 1416 Transistor Regulator 100ppm stability
Extraction of Beam At Extraction –Protons Circulating at 800 MeV –Two bunches with 200 ns gap Extraction System –3 fast kicker magnets deflect the beam into … –a septum magnet which lifts it into the EPB Kickers need to be fast to avoid beam loss –Go from zero to full field between passage of bunches
Extraction Details Kickers –3 units give 15 mr kick –Rise Time 80 nS –Flat Top 500 nS –5000A –40kV –50Hz pulsed Septum –~ 8 m downstream –8 Turn, 8900 A –DC –1.8 m long (21 degrees) –Lifts beam out of machine
ESSO Ring Vacuum PLC Control System
ESSO Neutron Beam Line Installations Complete electrical design Electrical Supply Detector Cabling Chopper Cabling Vacuum System Controls Several kilometres of cabling per beam line
Power Systems and the ISIS Synchrotron Andrew Kimber
Main magnet systems MM Power Supply and the White Circuit Capacitor bank replacement UPS Replacement 1MJ Storage Choke Summary Outline
Magnet systems Main Magnets 10 Bending Dipoles 10 Singlet Quadrupoles 10 Focussing Doublet Quadrupoles. Corresponds to 10 superperiods
Main magnet power supply 250A 1050A
Main magnet power supply For successful acceleration the same magnetic field is required in all the main magnets Main Magnets per super period: 1 Dipole 1 Singlet Quadrupole 1 Doublet Quadrupole How do we connect these? One power supply per super period Main Magnet System operates at 14.4kV Current changes from 250A to 1050 Amps Peak Power = 15.1 MVA For 10 super periods the Peak Power Required = 151 MVA Excessive Power Required !
Main magnet power supply Magnets have Inductance Inductance can store energy E = ½ LI 2 Capacitors also store energy E = ½ CV 2 Resonate the stored energy between Inductor and capacitor: With no losses in the system the impedances of the Inductance and the Capacitance would be identical and energy would be transferred with an alternating current between them and at a resonant frequency. Inductance reactance XL = Capacitive reactance XC ωL = 1/ωC ω = 2π f Resonant Frequency f = 1/(2π√LC )
Main magnet power supply Normal Temperature Magnets have Resistance Capacitors have losses Cables have losses If the losses << Inductance we have a high ‘Q’ oscillating system. We just require to supply make up power for the resistive and AC losses in the Magnets, Cables and Connectors.
The White Circuit WHITE CIRCUIT M G White, Princeton (1956) CERN Symposium Oscillate the magnet cell using capacitors and choke. Connect all the magnets together electrically and same current flows through each magnet. Permit DC bias current through split choke secondary winding Power required is to make up for the resistive losses in the copper, ac losses in the magnets and power supply losses. IM = IDC – IAC cos ω t Total of 1.75MW (150MVA peak for non resonant circuit)
The White Circuit
Main magnet power supply Replace capacitor bank with smaller more efficient units. Replace the Motor Alternator Set with a UPS System Replace the Choke. –Split the Choke into 10 separate units and build spare as well. PROGRESS TO DATE Capacitor bank replaced (2002) UPS system currently on order. Build a scale model to prove theory of split choke. Scale model chokes currently being ordered.
Old Capacitor Banks
New Capacitor Banks Replaced in 2002 Smaller units, space used for 1 old bank is now used for 5.
Motor Alternator Set
Previous Motor Alternator Set Electromechanical Single phase output 2 phases connected line to line and 1 disconnected Alternator phase locked to ISIS 50Hz reference 100Hz induced harmonic between raw mains and reference signal DC Motor Alternator Brentford Excitation PSU 12KVA Mains supply Phase locked to ISIS 50Hz reference signal transformer 5KV single phase 3.6KV single phase Storage choke and main magnets shaft
Current Motor Alternator Set DC Motor Alternator Brentford Excitation PSU 12KVA Mains supply Phase locked to ISIS 50Hz reference signal transformer 5KV single phase 3.6KV single phase Storage choke and main magnets shaft UPS Phase locked to ISIS 50Hz reference signal Alternator and UPS phase locked to ISIS 50Hz reference Factor of 2 improvement in AC stability
New UPS system Motor alternator set replaced with 4 300KVA units (1 redundancy) UPS units currently on order Installed by Q transformer 3.6KV single phase Storage choke and main magnets 240V three phase Gray converter circuit 720V single phase
Current 1MJ, 2H Storage Choke Ex-NINA, manufactured in the 1960’s Ten interleaved primary and secondary windings Choke windings and core: 90 tonnes Total weight (inc. oil): 120 tonnes 30 years of service State of insulation unknown, leaks oil, failure would result in ISIS being down for extended period of time Storage Choke
Replacement chokes …X10 Current 2H storage choke 10 off replacement 200mH chokes 1/5 scale models 40mH Minimise financial and technological risk Due September 04 Full scale prototype/spare
Replacement chokes Most probable design is a ‘frame’ type storage choke Energy stored (air gaps) = ½ L I 2 Energy stored/unit volume = ½ μ 0 B 2 Calculate dimension of air gaps For 200mH, 1010A, 100KJ, 0.9T:Volume ~0.3m 3 Size and distribution of these critical in controlling losses
Replacement chokes Testing of scale models to take place September 2004 Losses Stray magnetic fields Leakage inductance Linearity Noise (mechanical) Cost
Summary New capacitor banks –Installed 2002 New UPS system –Installed by Q New split choke system –Scale model testing Q –Prototype and production chokes 2005/6