Electric Power System of Tu
Contents
1. 200V 3 x 40 kVA 400 Hz AC system 3 10 13 The three phase 115 200 V AC power is delivered by three GT40PCh6 wound field synchronous generators The fourth GT40PCh6 AC generator is the APU generator The APU is also equipped with 27 V DC GS 12TO starter generator The secondary three phase 36 V 400 Hz 46 8 A 2 x 3 kW AC system takes power from the main system via two three phase 206 37 V Dy TS330S04B transformers The pri mary windings of TS330S04B transformers are fed from the navigation piloting system NPK bus bars The 115 200 V AC and 36 V AC power systems are shown in Fig 3 and de scribed in Table 1 The third power system is the 27 V 200 A DC single circuit system Fig 4 which receives power from the main system via transformer and three VU 6A rectifiers and four 2ONKVN 25 batteries The emergency 36 V AC power system instead of RAT consists of two 20 30 36 V 400 Hz 250 VA PTS 250 tran sistor inverters fed from batteries It feeds among others the gyro horizon AGR 144 Another single phase 115 V emer gency system takes electric power from batteries via POS 125TCh solid state converter The simplified electrical diagram of 115 200 V AC power generation system with three main generators and APU gen erator is shown in Fig 5 The block diagram of overall electric system of the Tu 154M is shown in Fig 6 frame No 63 No 226 r including aE 294 al 225 iy 36 No 34 including No 225 5 fra2. the ullage in each tank to the outside air 7 The Tu 154M is equipped with the vent system The Tu 154 uses fuel Jet A 1 Jet A 1 is a kerosene grade of fuel suitable for most aircraft turbine engines It is produced to a stringent internationally agreed standard lt 2 6 8 9 0 ms 8 8 Wing anti ice system Most civil aircraft use hot bleed air for anti ice control of outer wing leading edges 7 The Tu 154M must use electric resistive heating for anti ice of the wing leading edge slats as the turbofan engines are tail mounted and located far away from the wings This would make the hot air bleed system very heavy and cumbersome The Tu 154M has three phase 115 V electrical wing anti ice heating system Fig 20 3 9 14 To save elec trical energy heating elements are fed cyclically by adequate determination of time period Under cyclic heating a thin layer of ice accumulates on slats which does not deteriorate aero dynamic properties of the aircraft When the accumulation reaches a thickness threshold and the temperature of skin increases the ice is taken out by the air stream The generator GT40PCh6 No 2 driven by the mid turbo fan engine Fig 5 feeds only the electric grid 2 dedicated to heating wing slats The electric apparent power is 43 6 kVA at 115 V phase voltage and lt 130A Heating elements composites of one half of slats are divided into eight sections The other half of slats has also eight sec
3. 13 Fig 19 Booster fuel pump ECN 325 a cross section of fuel pump and induction motor b feeding cable tubing 1 grid 2 induction motor 3 motor housing 4 shaft 5 tube 6 7 sealing rub ber rings 8 pump housing 9 rotor 10 cover 11 snail 12 impeller 13 channel 27 conduit metal tube 28 tubing 29 ter minal block 30 cover 31 electric cable Construction of transfer fuel pump ECN 323 is similar 3 9 12 Fig 20 Leading edge wing anti ice system 1 slat 2 outer skin sheathing 3 5 7 thermal glass insulation 4 thermal knife 6 heating element 8 inner skin sheathing 9 14 gineer top switchboard middle console of pilots aircraft pan els panels of automatic pressure control workplace of navi gator etc In addition each crew member has lamps with a red cylindrical optical filter that allows the light to change from white to red General illumination of passenger cabins has been de signed in form of central and side fixtures with fluorescent lamps Each central fixture has two fluorescent lamps con tained in the reflector and sealed with milky color plexiglas Side lights are built in into the lower panels of luggage bins Individual passenger lamps equipped with lenses to focus the ligh beam are used at night after turning off the lights of the passenger compartment Lamps are mounted in the bottom panel of lug
4. Aerospace University Samara 2005 10 Timofieyev J M Electrical equipment of Tu 154M aircraft Federal Air Transport Service of Russia Academy of Civil Avi ation Sankt Petersburg 2000 11 Tu 154 Catalogue of parts and compilation of units Chapter 27 Control in Russian Avia Media 1984 updated 2003 12 Tu 154M User s technical guidance Chpt 28 Fuel system 13 Tu 154B User s and technical service manual Book 7 Part 1 Electric equipment in Russian Samara Aviakor 1994 14 Wing of Tu 154 aircraft in Russian cabinet of aircraft construction web 1 2 bei b 3 hei 4 Li 5 Lo 8 La Virtual page http cnit ssau ru virt _ lab krilo index htm Accessed on Nov 28 2012 15 Wood R H SweginnisR W Aircraft accident investigation 274 ed Casper WY USA Endeavor Books 2006 16 Znichenko V I Construction and user manual of Tu 154M aircraft Federal Air Transport Service of Russia NLMK Academy of Civil Aviation Sankt Petersburg 1998 Authors Prof Jacek F Gieras Ph D D Sc IEEE Fel low Department of Electrical Engineering Electrical Ma chines and Drives University of Technology and Life Sci ences Al S Kaliskiego 7 85 796 Bydgoszcz Poland email jacek gieras utp edu pl PRZEGLAD ELEKTROTECHNICZNY ISSN 0033 2097 R 89 NR 2a 2013
5. Jacek F GIERAS University of Technology and Life Sciences Bydgoszcz Electric Power System of Tu 154M Passenger Aircraft Abstract The paper discusses the electric power system of the Tu 154M aircraft After brief introduction to aircraft power systems the results of reverse design and analysis of the GT40PCh6 wound field synchronous generator including short circuit have been presented Electric power distribution and assignment of electric grids channels to respective aircraft energy consumers has been discussed Most important electric loads i e the fuel system with electric motor driven pumps wing anti ice electric system and exterior and interior lighting equipment have been described An example of failure of GT40PCh6 synchronous generator is the fire of the Tu 154B 2 on January 1 2011 before taking off at Surgut airport flight 7K348 Streszczenie Artykul omawia system elektroenergetyczny samolotu Tu154M Po krotkim wprowadzeniu do systemow elektroenergetycznych samolo tow przedstawiono wyniki projektowania odwrotnego oraz analizy generatora synchronicznego GT40PCh6 o wzbudzeniu elektromagnetycznym z uzwglednienium przebiegow pradow podczas zwarcia Opisano dystrybucje energii elektrycznej oraz przyporzadkowanie odbiornikow energii elek trycznej samolotu do poszczegolnych sieci kanalow Scharakteryzowano najwazniejsze obciazenia elektryczne tzn system paliwowy z pompami napedzanymi silnikami elektrycznymi system elektryczny zapo
6. PTS 250 emergency convener Wo 2 Jaise 36 V for redundancy k oh xe 36 V right grid TP ase 36 V Fig 6 Block diagram of electric power system of Tu 154M 16 D OKU No3 GT40PChE 3phase 115 200 V _ GEU No 2 fuel pumps No 2 4 6 7 9 11 fuel control system rec tifiers VU 6B No 2 No 3 air conditioning system hydraulic pumping station NS 46 of the third hydraulic system house hold equipment and other equipment The total power con sumption is 12 kVA 45 A without household equipment and NS 46 The household equipment needs 13 kVA 60 A In the case of failure of one of the generators its grid is automatically reconnected to the operating generators The GPU supplies all three electric grids After starting any turbofan engine and after switching on any GT40PCh6 generator the first and the third grid is automatically con nected to this generator while the GPU feeds only the sec ond grid If two generators are on the GPU is automatically disconnected from the aircraft electric power system Control and protection devices of the main power sys tem are located on the power panel of the flight engineer The three phase 36 V 400 Hz two channel electric power system feeds the Kurs MP 2 landing navigation and control unit ARK 15M radio compass Groza 154 radar Doppler ef fect velocity and drift angle measure system DISS 3P and hydraulic pressure gauge MET 4B The 36 V AC system a
7. biegajacy osadzaniu sie lodu na frontowych powierzchniach skrzydel oraz oswietlenie zewnetrzne i wewnetrzne Przykladem awarii generatora synchronicznego GT40PCh6 jest pozar Tu 154B 2 w dniu 1 stycznia 2011 przed startem na lotnisku w Surgucie lot 7K348 System elektroenergetyczny samolotu pasazerskiego Tu 154M Keywords aircraft electric power system distribution system electric loads electric motor driven fuel pumps fuel system lighting synchronous generator Tu154M wing anti ice electric system Stowa kluczowe generator synchroniczny odbiorniki energii oswietlenie elektryczne pompy paliwa napedzane silnikami elektrycznymi system dystrybucji energii elektrycznej system elektroenergetyczny samolotow system odmrazania elektrycznego skrzydel system paliwowy Tu 154M Introduction to aircraft electric systems The function of the aircraft electrical system is to gener ate regulate and distribute electrical power throughout the aircraft 4 7 Aircraft electrical components operate on many different voltages both AC and DC Most systems use 115 200 V AC 400 Hz and 28 V DC There are several differ ent electric generators on large aircraft Fig 1 to be able to handle loads for redundancy and for emergency situations which include 4 7 8 1 engine driven main generators 2 auxiliary power unit APU 3 ram air turbine RAT 4 external power i e ground power unit GPU Each of the engines on an aircraft drives on
8. by DC 27 V brush motors Table 3 A flange mounted motor and pump constitute one integral unit Fig 19a The feeding cables in fuel tanks are in aluminum tubes Fig 19b Wiring system that delivers electric energy to fuel pump mo tors must be protected against electrical arcing and accumu lation of static electricity that under some circumstances can cause ignition of the fuel air mixture in the wing tank 6 7 9 In general there are two types of fuel pumps on typical aircraft 7 e Fuel transfer pumps e g ECN 323 which perform the task of transferring fuel between the aircraft fuel tanks to ensure that the engine fuel feed requirement is satisfied e Fuel booster pumps e g ECN 319 ECN 325 also called engine feed pumps which are used to boost the fuel flow from the aircraft fuel system to the engine 304 Fig 16 Tu 154M fuel tank configuration No 1 center wing tank CWT i e collector tank No 2 inner left and right wing tank No 3 outer left and right wing tank No 4 additional tank 12 Table 3 Fuel pumps of Tu 154M ECN 319 ECN 323 Type Emergency Electric Rated Starting current Pressure drop kKG cm 1 6 Flow l h 1 500 Mass of pump kg 4 Transfer Booster 12 Induction Induction brush cage cage 2 DC 27 115 200 115 200 lt 15 lt 4 unknown lt 15 6 2 000 3 500 7 000 12 000 Commercial aircraft use open vent system to connect
9. d starting from the core part of the wing to the end of the wing The current is on for 38 5 s and off for 269 5 s for each sec tion In the leading part a thermal knife is installed along the slats This part is made of 20 mm wide X20H80 NiCr foil The thermal knife is not fed cyclically it is steadily under current and is isolated from the outer skin by three layers of glass fiber 3 Fig 20 Also the three layers 5 isolate the thermal knife from the heating element On the inner skin sheathing of heating element of the slat thermal switches for cyclic operation of sections and thermal knife are installed Thermal switches protect slats and heating el ements against overheating Lighting The lighting equipment of the Tu 154M is divided into external and internal equipment External equipment is in tended for taxiing takeoff landing and indicate the plane in the air space at night Interior equipment is used for illumina tion of the cockpit passenger cabin and other chambers of aircraft and emergency lighting The external lighting equipment includes wing navigation position lights BANO 57 with 70 W SM 28 70 lamps 115 V SMI 2KM anticollision flashing lights 45 flares min and 27 V 35 5 A PRF 4 landing taxi lights The cockpit is equipped with a general illumination sys tems and lamps for lighting control boards panel of flight en 305 PRZEGLAD ELEKTROTECHNICZNY ISSN 0033 2097 R 89 NR 2a 20
10. e form of pipes with holes to allow air to heat the inner surface 1500 1000 500 500 Fig 14 at 0 95 ms PRZEGLAD ELEKTROTECHNICZNY ISSN 0033 2097 R 89 NR 2a 2013 Armature current Ias at line to neutral short circuit of GT40PCh6 synchronous generator The peak current is 1108 2 A 20 3 ms 25 time Fig 15 Armature current J at two lines to neutral short circuit of GT40PCh6 synchronous generator The peak current is 1130 A at 0 6 ms Table 2 Parameters of GT40PCh6 synchronous generator Stator Number of phases Connection Rated speed rom Rated frequency Hz Stator phase voltage V Stator rated current A Armature winding resistance per phase at 25 C Base impedance d axis synchronous reactance p u g axis synchronous reactance p u salient pole 0 58 Type of rotor Pole arc to pole pitch ratio Number of poles 8 DC field current at nominal load and PF 0 75 A Total moment of inertia kgm 45 58 approx 0 06 of leading edges The hot air flow to the outer wing lead ing edges is controlled by the wing anti ice valve 7 The Tu 154M has electric anti ice control system with heating el ements embedded in slats The fuel system of the Tu 154M uses electric motor driven centrifugal pumps ECN 319 ECN 323 and ECN 325 Fuel pumps ECN 323 and ECN 325 are driven by 115 220 V AC induction motors Fig 18 and fuel pumps ECN 319 are driven
11. e integrated drive gen erator Failures of other electrical equipment On September 7 2010 the Tu 154M RA 85684 Alrosa Mirny Air Enterprise Flight 514 aircraft from Udachny to Moscow suffered a complete electrical failure en route leading to a loss of navigational systems The electrically operated fuel transfer pumps were also affected and prevented transfer of fuel from the wing tanks to the engine supply tank in the fuse lage After emergency decent below cloud level the crew were able to spot an abandoned air strip near town of Izhma Fig 23 The abandoned air strip is 1325 m whereas the Tu 154 requires a minimum of 2200 m The aircraft landed at a speed of 350 to 380 km h faster than normal due to the lack of flaps Although the flaps are powered by hydraulics the switches operating them are electrical The impact was damped by the young trees which have grown since the air port was closed All nine crew members and 72 passengers evacuated using the aircrafts evacuation slides No injuries were reported Fig 23 Emergency landing of Tu 154M RA 85684 at abandoned air strip near town of Izhma_ on September 7 2010 http www airlinereporter com wp content uploads 201 1 11 TU154a jpg On November 17 1990 the cargo TU 154M CCCP 85664 of Aeroflot Airways was heading through Czech terri tory with a load of Winston cigarettes from Basel to Moscow A switched on cooker in the kitchenette caused a fire on board of th
12. e or more a c generators Fig 2 via special transmission system Fig 1 Aircraft generators 1 main generator 2 APU 3 RAT 4 GPU 4 The electricity produced by these generators is used in normal flight to supply the entire aircraft with power The power generated by APUs is used while the aircraft is on the ground during maintenance and for engine starting Most aircraft can use the APU while in flight as a backup power source RATs are used in the case of a generator or APU failure as an emergency power source External power may only be used with the aircraft on the ground A GPU portable or stationary unit provides AC power through an external plug Aircraft generators are typically three phase salient pole wound field synchronous generators with outer stator with distributed parameter winding and inner rotor with con centrated coil winding 4 The field excitation current is pro vided to the rotor with the aid of a brushless exciter system PRZEGLAD ELEKTROTECHNICZNY ISSN 0033 2097 R 89 NR 2a 2013 consisting of two synchronous machines i e wound field synchronous exciter and permanent magnet PM subexciter The power circuit is shown in Fig 2 PM brushless genera tors are rather avoided due to difficulties with shutting down the power in failure modes There are also attempts of us ing switched reluctance SR generators with no windings or PMs on the rotor A generator control unit GCU or vol
13. e plane and the crew decided to land at the clos est possible place The crew made an attempt of emergency landing on the field near Dubenec village in the East Bo hemia There were only 6 crew members on board all of them survived the air disaster On February 18 1978 the Tu 154A CCCP 85087 of Aeroflot Airways was standing on the apron at Tolmachevo Airport Novosibirsk The cabin heater was left working unat tended between flights A rag caught fire which incinerated the cabin A fire that broke out in the passenger cabin en 307 gulfed the rear part of the airframe The forward fuselage burnt out There were no fatalities Conclusions The electric system of the Tu 154M aircraft is an out dated system typical for aircraft being designed in the 1960s There are three GT40PCh6 wound field synchronous gener ators driven by D 30KU low bypass turbofan engines and one GT40PCh6 generator driven by the TA 6A APU turboshaft engine The APU is also equipped with the 27 V DC GS 12TO starter generator The Tu 154M is not equipped with a RAT Main synchronous generators GT40PCh6 are air cooled generators Air cooling reduces the rated power and in creases the mass of generators Nowadays modern VSCF wound field synchronous generators are oil cooled with rated power up to 250 kVA Boeing 787 Dreamliner Reversed design and analysis of GT40PCh6 main syn chronous generators deliver important information on steady state and transient pe
14. els 3 Nominal power per channel Maximum power per channel 40 kVA 50 kVA 5 min overload power 60 kVA 5 s overload power 80 kVA Frequency Hz 400 Nominal current per channel A 111 Maximum current per channel 138 Power factor 0 8 to 1 0 modern aircraft power wires feeding e g electric motors are not routed through the cockpit Switches in the cockpit are connected to light current wires control wires which ac tivate relays of heavy current circuit 23 irame No 26 7 iii 17 y j 3 3 al 14 irar ie as T 12 Bs frame No 63 15 1 1618 20 4 22 8 13 Fig 3 Main power distribution systems 115 220 V AC and 36 V AC of Tu 154M 1 rectifiers VU 6A backup and No 1 2 rectifier VU 6A No 2 3 right junction box JB 115 200 V 4 converter PTS 250 No 2 5 converter PTS 250 No 1 6 JB of kitchenette 7 JB of anti ice system 8 right panel of generators 9 generator GT40PCh6 No 3 10 JB of APU 200 V 11 generator GT40PCh6 of APU 12 generator GT40PCh6 No 2 13 generator GT40PCh6 No 1 14 external power connector for SHRAP 400 3F GPU 15 left panel of generators 16 left JB 115 220 V 17 transformer No 2 18 transformer No 1 19 right JB 36 V AC 20 left JB 36 V AC 22 flight attendant s switchboard 23 converter POS 125Ch 3 13 Electric power supply system of Tu 154M The main power supply system of the Tu154M is a three phase 115
15. g effects of frost and dew shock accelerations up to 6g The housing monoblock is made of magnesium alloy with pressed steel sleeve mounted on the drive side around o1 amp W PO 302 Fig 8 APU with GT40PCh6 synchronous generator and TA 6A tur boshaft engine 1 fuel pump regulator 2 sensor of tacho genera tor 3 synchronous generator GT40PCh6 4 leads of synchronous generator 5 air oil heat exchanger 6 adapter 7 fan 8 stabi lizer of oil pressure 9 front Suspension rigging 10 grid of com pressor 11 radial circular entrance 12 compressor 13 gas col lector 14 combustion chamber 15 evaporation tube 16 head of flame tube 17 snail 18 exhaust pipe 19 air bypass pipeline 20 turbine 21 air regulator 22 bleed air pipe 23 spring 24 reducer 3 re iii ae eae me A Aa if Be DAY A LRE O Number of lubrication point 1 4 according to lubrication chart Fig 9 Wound field air cooled synchronous generator GT40PCh6 1 armature core of main generator 2 armature winding of main generator 3 armature winding of exciter 4 armature core of exciter 5 field winding of exciter 6 pole 7 field excita tion system of exciter 8 rotor pole of main generator 9 ar mature of subexciter 10 PM 11 armature winding of subex citer 12 end shield 13 nozzle 14
16. gage bins Single lamp fixtures are mounted in the toilets hallways kitchenette and above the mirrors Emergency lighting is provided to illuminate the passen ger areas on the ground when the power is supplied from the on board batteries During flight the emergency lighting of passenger cabins is turned on at night after turning off the general illumination Emergency lighting is installed in pas senger cabins lobbies dressing rooms and toilet passages PRZEGLAD ELEKTROTECHNICZNY ISSN 0033 2097 R 89 NR 2a 2013 Failures of electric power system Failures of synchronous generators The mean time between failures MTBF of GT40PCh6 syn chronous generators is estimated as approximately 8000 to 8500 flight hours 2 3 13 16 UNE COS fa Fig 21 Tail part of Tu 154B 2 RA 85588 after fire at Surgut airport on January 1 2011 2 FE Fig 22 Closed electric circuit on assumption of abnormal scenario corresponding to 21st contactor TKS233DOD switching generator No 3 on grid 2 There is known at least one case of main generator fail ure i e the Tu 154B 2 RA 85588 while operating flight 7K 348 on January 1 2011 from Surgut to Moscow Domode dovo The plane was taxiing to the runway while preparing for its takeoff from Surgut when the right engine caught fire on the taxiway Fig 21 Three out of 126 passengers and 8 crew members died Russia s Interstate Aviation Committee MAK released their fina
17. housing 15 bearing 16 hollow shaft of rotor 17 shaft end 18 flanges 19 fan 20 field winding of main generator 21 point of lubrication http sO10 radikal ru i314 1010 42 cba147b70185 jpg the ball bearing The bearing nest has a pocket for the col lection of waste grease that is removed from it with the aid of a plunger Lubricant is applied to the bearing on the oil line through the point of lubrication There are longitudinal ribs on the inner surface of the housing which increase its rigidity and form channels for pas sage of cooling air Windows in the enclosure at the drive side are designed to exit the air Titanium flange screwed to the end shield mounts the generator on the engine Fig 9 A box on the outer surface of the housing contains a differential current transformer for protection of the generator The rotor has two ball bearings Seals of the bearings are threaded type with extra cuffs The rotor salient poles armature of the exciter and PMs of subexciter are pressed on the hollow shaft The rotating passive rectifier consists of six silicon diodes D232A Cooling of the generator is accomplished by blowing air at a flow rate varying from 0 1 to 0 3 kg s Dimensions material data and winding diagrams of the GT40PCh6 synchronous generator are not available 3 13 10 To obtain dimensions winding parameters and detailed 303 Fig 10 Magnetic flux distribution in the cross section
18. is also a reserve 40 kVA 115 200 V 400 Hz power source the so called APU which consists of GT40PCh6 synchronous generator driven al independent TA 6A turbine engine Fig 8 DBHTATENb SOKYIKM Ty 154M Mn G2M Htn 76 vik nes Fyi Fig 7 Turbofan engine D 30KU 1 inlet guide vanes heating collec tor VNA 2 centrifugal air separator of oil system 3 fuel oil heat exchanger 4 main oil pump 5 front main accessory drive gear box 6 hydraulic pump for thrust reverse 7 fuel pump 8 sensor of referred revolutions 9 place for aircraft hydraulic pumps NP 25 and NP 89 10 fuel pump regulator 11 temperature sensor 12 centrifugal regulator of low pressure LP rotor 13 rotational speed sensor for the LP rotor 14 synchronous generator GT40PCh6 15 rear accessory drive gearbox 16 constant speed drive CSD 17 mechanism of frequency correction 18 air turbine of CSD 19 air turbo starter 20 overlapping cover of turbo starter 21 oil removal pump http ru wikipedia org The longitudinal section of the GT40PCh6 synchronous generator is shown in Fig 9 From better packaging point of view the PM brushless subexciter is placed inside the exciter The GT40PCh6 generator operates smoothly under the following conditions 1 ambient temperature from 100 to 60 C cooling air temperature from 60 to 60 C atmospheric pressure up to 124 mm H
19. l report in Russian concluding the probable cause of the accident was the outbreak of fire in the right genera tor panel located between frames 62 and 64 in the cabin 2 The generators were connected on the network after the en gine start and exit to the idle mode The cause of the fire was an electrical arcing produced by electrical currents ex ceeding 10 to 12 times the nominal current when two gener ators not synchronized with each other were brought online but got connected together instead of being connected to par allel busses Fig 22 The unsynchronized operation of the generators can be attributed to 1 Poor technical conditions of contacts TKS233DOD Fig 22 responsible for connecting the generators with the electrical busses that were damaged by prolonged op eration without maintenance A contact normally open was welded and fractured insulation material moved be tween contacts that are normally closed These abnor 306 mal contact positions led to the connection between No 2 and No 3 generators Fig 22 2 Differences in the schematic diagrams of generator No 2 and generators No 1 and 3 When the switch is moved from check to enable with no delay in the neutral position the generator 2 is brought on line without time delay This leads to increased wear of normally closed contacts in the TKS233DOD unit The specific design of the electrical systems ensures power supply to each bus from either the APU or engin
20. lso supplies the gyro horizon attitude indicator but its power is supplied independently of the PTS 250 converter which re ceives electrical energy from batteries The PTS 250 No 1 converter is used as an emergency 36 V AC power source Fig 6 Connection of the converter to the network is made automatically The on board 27 V DC power system consists of three VU 6A rectifiers GS 12TO starter generator mounted on the APU and two four 20NKBN 25 batteries Fig 4 The VU 6A rectifiers are the basic DC power sources They get the power from the first and third grid from the main 115 200 V AC system There are two basic rectifiers and the third rec tifier is for redundancy Fig 6 The third rectifier is switched on automatically in the case of failure of one of the basic rec tifiers and operates in parallel with the remaining rectifiers There is also provision for forced connection of the third re serve rectifier The 27 V DC GS 12TO APU mounted starter generator delivers power to the DC grid after starting the APU on the ground until turbofan engines are started and GT40PCh6 synchronous generators operate n the case of failure of the main 115 200 V power system in the air rechargeable batter ies are used to supply the most important loads and to start the APU on the ground in the absence of GPU Under normal PRZEGLAD ELEKTROTECHNICZNY ISSN 0033 2097 R 89 NR 2a 2013 operation batteries are connected in parallel to s
21. me Nea 8 Fig 4 Power distribution system 27 V DC of Tu 154M 1 Rectifier VU 6A No 2 2 right panel of protection control 3 Rectifier VU 6A No 1 4 Left panel of protection control 5 junction box JB of kitchen 6 left power JB 27 V DC 7 electrical panel of flight attendant 8 rear JB in left panel of generators 9 JB of APU and batteries 10 batteries 2ONKBN 25 12 JB of batteries 12 JB of VU 6A backup rectifier 14 backup rectifier VU 6A 15 PT JB 16 electrical panel of household devices 17 electrical panel of crew cupboard 18 flight attendant s switchboard 13 ds Fo 200 A 100A a O0 A GENERATORS e r 63 Fig 5 Simplified schematic of main electric power generation sys tem 115 220 V AC when all generators G1 G2 and G3 are in par allel 1 contactor TKS133DOD reconnection of grid No 1 on gen erator No 3 2 contactor TKS233DOD switching generator No 1 on grid 5 contactor TKS233DOD switching APU on grid No 2 17 contactor TKS233DOD switching generator No 2 on grid 20 contactor TKS233DOD reconnection of grid No 3 on generator No 1 21 contactor TKS233DOD switching generator No 3 on grid 27 contactor TKS233DOD switching APU or GPU on grid No 3 38 contactor TKS233DOD switching APU on grid 2 Electric power distribution The main three phase 115 200 V 400 Hz powe
22. mooth the DC bus voltage ripple Rechargeable batteries are installed in the rear fuselage under the floor of the technical compart ment They can be accessed through a removable hatch in the floor In addition there is a 27 V AC power supply designed for household appliances electric kettles and electric warmer in the kitchenette buffet The system gets its power from the main system through a TS 330S04A transformer connected to the grid No 3 via a switch mounted on the flight attendant switchboard Figs 3 and 4 The transformer is installed on the right board near the frame No 35 in junction box JB of the kitchenette Fig 3 The single phase 115 V AC 400 Hz power supply pro vides electric power to Landish 20 FM radio station radio system RSBN 2SA of near range navigation Kurs MP 2 nav igation and control unit and other radio equipment as well 2 A 7A temperature meters of engine exhaust gases 3 In the case of emergency the electrical power to these loads comes from the converter MA 100M which is supplied from batteries The connection of converter is made automatically The cross section of basic distribution wires is e 1 93 to 35 0 mm for AC systems e 1 5 to 70 0 mm for DC systems Synchronous generators The main generators are three 40 kVA 115 200 V 400 Hz CSD GT40PCh6 wound field synchronous generators driven by three D 30KU low bypass turbofan engines Fig 7 Each generator feeds one channel grid There
23. nk to store fuel In larger aircraft the fuel is also stored in the structural wing box within the fuselage A typi cal wing tank is irregular long and shallow 7 The fuel is in direct contact with the outside skin The Tu 154M has six fuel tanks one central fuel tank CWT No 1 two inner wing tanks No 2 two outer wing tanks No 3 and one additional tank No 4 The Tu 154M fuel tank configuration is shown in Figs 16 PRZEGLAD ELEKTROTECHNICZNY ISSN 0033 2097 R 89 NR 2a 2013 Fig 12 Armature current asp at three phase short circuit of GT40PCh6 synchronous generator The peak current is 911 2 A at 0 9 ms 1000 Fig 13 Armature current Iasp at line to line short circuit of GT40PCh6 synchronous generator The peak current is 944 6 A at 0 95 ms and 17 The tanks No 3 are between spars 1 and 3 and ribs 14 and 45 of detachable parts of wings 12 The CWT tank is generally categorized as hazardous due to the proximity to external heat sources e g aircon ditiong units 7 It requires tank inerting with the aid of nitrogen enriched air from the on board inert gas generating system The tanks No 1 and 4 of the Tu 154M are inerted in the case of emergency landing without landing gears The left and right wing tanks are usually categorized as nonhaz ardous as there is mostly no proximity of heat sources 7 The wing leading edge slat section is equipped with anti ice control system typically with hot air ducts These ducts tak
24. of GT40PCh6 synchronous generator as obtained from the 2D FEM 190 V o analytical calculations o FEM 180 140 10 20 20 40 50 7a 0 50 a 100 field excitaion current Fig 11 Open circuit characteristics at synchronous speed ns const obtained from analytical calculations and 2D FEM performance characteristics of the GT40PCh6 synchronous generator Table 2 a reverse design on the basis of avail able sources 8 10 13 has been done The 2D FEM has been used for electromagnetic analysis and synthesis The 2D magnetic flux distribution in the cross section of the main generator as obtained from the FEM is shown in Fig 10 The open circuit characteristics 8 at synchronous speed n f p const obtained from analytical calcu lations and 2D FEM are shown in Fig 11 Short circuit currents can exceed more than 11 times the nominal current Figs 12 to 15 shows the armature current Tash f t waveforms for three phase line to line line to neutral and two lines to neutral short circuits of the GT40PCh6 synchronous generator The most dangerous are line to neutral Fig 14 and two lines to neutral Fig 15 short circuits The obtained short circuit current waveforms are very important since the subtransient and transient short circuit currents help to evaluate the possible damage during the electrical power system failure Fuel supply system Civil transport aircraft use the wing structure as an inte gral fuel ta
25. r supply system is a three channel system Figs 3 5 and 6 One GT40PCh6 generator feeds one channel electric grid The generator No 1 mounted on the left turbofan engine No 1 feeds the grid No 1 which in turn feeds the left au tonomous bus bars left bus bar of navigation piloting sys tem NPK radio navigation equipment anticollision flashing lights SMI 2KM control systems of slats and stabilizers mo tors No 1 fuel pumps No 1 3 5 8 10 rectifiers VU 6B No 1 No 3 passenger cabins lighting heaters of windshields of cockpit hydraulic pumping station NS 46 of the second hy draulic system and other loads The total power consump tion of the grid No 1 is 23 2 kVA 70 A excluding NS 46 The generator No 2 of the grid No 2 mounted on the center engine No 2 feeds anti ice electric heating elements of leading edges of wings slats The power consumption is 43 6 kVA 130 A The third grid No 3 powered by the generator No 3 in Stalled on the right engine No 3 is loaded with the right au tonomous bus bars right bus bar of navigation piloting sys tem NPK control system of slats and stabilizers motors 301 PRZEGLAD ELEKTROTECHNICZNY ISSN 0033 2097 R 89 NR 2a 2013 TS 3306048 transformer D 30KU Nol 9 ST40PCh6 aphase 175 200 V POS 125 emergency converter i phase Wav 11200 Y grid iM Baliores Ha 1 and 3 D J0KU Mo 2 m Zz 1 PTS 250 amerngency converter M 1 E Hi He
26. rformance of these machines Tran sient characteristics especially short circuit waveforms are very helpful in investigation of electric power system after malfunction failure or crash BIBLIOGRAPHY Ellis G Air crash investigation of general aviation aircraft Greybull WY USA Capstan Publications 1984 Final Report on results of investigation of aviation accident involving the Tu 154B 2 tail number RA 85588 airport Surgut on January 1 2011 in Russian Interstate Aviation Committee MAK Moscow 2011 Electrical equipment of aircraft Tu 154B M in Russian Rilsk Aviation College of Technology 2000 Gieras JF Advancements in electric machines London Boston Dordrecht Springer 2008 Hill R Hughes W J A review of flammability hazard of Jet A fuel vapor in civil transport aircraft fuel tanks Re port DOT FAA AR 98 26 US Dept of Transp Springfield VA 1998 6 Kosvic T C Zung L B Gersten M Analysis of fuel tank fire and explosion hazards Technical Report AFAPL TR 71 7 Air Force Propulsion Laboratory WPAFB Ohio 1971 7 Moir I Seabridge A Aircraft systemes mechanical electri cal and avionics subsystems integration 3 ed Chichester UK J Wiley amp Sons 2008 Ronkowski M Michna M Kostro G Kutt F Electrical ma chines around us in Polish Gdansk University of Technology Gdansk Poland 2011 9 Soshin V M Aircraft Tu 154M book 2 ed Samara State
27. tage regulator is used to control generator output The generator shaft is driven by a turbine engine with the aid of gears or directly by low spool engine shaft Excision winding Of easter Armature of main generator Rotating recife I I i Armature i of esciter I Encilation winding of main generator l loan es l l AIRCRAFT POWER ELECTRONICS a CONVERTER PRIME MOVER AIRCRAFT ENGINE Fig 2 Architecture of main wound field synchronous generator 4 Typical AC power system of aircraft is 115 200 V 400 Hz three phase system Since the speed of an aircraft en gine varies from full power speed to flight idle speed typically 2 1 and frequency is proportional to the generator rotational speed a device for converting a variable speed to constant speed is necessary 7 The so called constant speed drive CSD i e a complex hydromechanical device was common until the late 1980s Nowadays solid state converters have replaced unreliable CSDs with variable speed constant fre quency VSCF systems Typical aircraft have from 16 to 160 km of wire installed such that wire from one system is often collocated with wire from many other systems Electrical wiring can be classified into power wiring heavy current and light current wiring In 300 Table 1 AC power systems of Tu 154M aircraft Voltage V 115 220 Number of phases 3 Nominal power of the system 120 kVA Number of chann
28. tions Section are fed in the following sequence Space between the fuel surface and upper wall of the tank lower lewel fue managenent do b gsiar fuel pump SUH 325 transfer fuel pump SUH 323 Tank Mo 2 emergency booster fuel pump SLH 319 rf 1 ht for APL i l ll EJ 5425 kg 6 G i a G SSS raiu valve mm iene unloading yabee JR sensor indicator of pressure COy 24 0 18 MCTB 02 m sensor of densitometer ONES 1T vamin iuba m sensor of flowmeter JPTMC 1047 CED booster pump QCH44TB T Of turboran engine fuel filter of turbine engine Fig 17 Tu 154M fuel system layout Fuel tanks fuel pumps fuel transfer lines D30KU engine and APU have been shown 1 2 feed lines of upper transfer from tanks No 4 and 1 to tank No 2 3 faucet of reserve transfer 4 antifire faucet 5 discharge faucet 6 con nector for maintenance of engines 12 16 Ls ee Ai pee Eee a Boe J Ree A S it IE E A Fs ent ae xine PP eA tt S ee 512 caper eas pares ae meet rene Ses se ae rri og direction of flow of working fluid Fig 18 Layout of ECN 323 and ECN 325 fuel pumps 1 tank 2 outlet 3 axial wheel 4 collection snail 5 impeller 6 7 safety grid 8 connecting channel 9 electric motor 10 circulation ori fice 12 1st ard gih 4st and gth Sections are numbere
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