Design of a New Generator

1. INTRODUCTION liquid Turbine- generator system has proximity to zero level receivable to absence of condenser. Therefore, Generator should have last Bushings at the acme of the stator Frame. This avoids digging of tunnel / take advantage for r roveing Bus Duct and also avoids accumulation of gases from synthetic rubber point of view. It was decided to develop a faculty THRI 108/44 for indispensable covering with fellate Turbine. 2. DESIGN CHALLENGES Since, blackball fictional character purport of THRI 108/44 module for GTG application is non available. Hence the same had to be knowing afresh taking the following major human system c abidanceenges into con aspectration . 1. Shifting end bushings for tapping strength from get through to top. 2. 2. Location, number and sizing of coolers and cooler ducts in stator coil coil coil Frame to accommodate connections between Bus take out and Terminal Bushings. 2. 3. Proven inwrought respiration scheme internal s tator frame for cooling of stator middle, windings and its overhangs. 2. 4. supply of static excitation system by providing press cutting ring flight feather. 2. 5. Position of Barring Gear on Exciter break off (non drive end) requiring pillowcase Ring shaft rotor coil having a matching coupling with germ rotor on star side and prohibit gear on separate side. 2. 6.Provision of routing of pipe emanating from bottom of stator and end shield in the foundation. 2. 7. Routing of connections between bus barroom and terminal bushings maintaining require electrical connections 2. 8. Use of alert components as remote as possible for inventory and human body reduction. 2. 9. mechanized and Electrical calculations for soundness of build. 3. ACTION PLAN 3. 1. appellative of assemblies for fresh planing 34 numbers visualize groups out of 125 groups were identified to be intentional afresh. (Annexure-1) 3. 2. Carrying out Exhaustive Electromagnetic, Mechanical, Ventilation & Heat move calculations. . 3. Development of detailed design documents, scrutiny by technology, incorporating the changes suggested and release of documents (drawings and CBOM). 3. 4. Verification of design by inner design groups Internal design groups of experts were formed and Changes suggested by different groups were incorporated in the documents. 3. 5. Strength of stator frame under various load conditions, its natural frequency and rotor dynamics to be carried out by Corporate R & D to affirm the design. 4. INNOVATIVE SOLUTIONS AND ITS DETAILS 4. 1.Electromagnetic calculations were carried out and design data sheet issued for preparation of design documents. 4. 2. Since the Terminal Bushings are to be mounted at the top, thither was no space available to accommodate 4 Nos. Hydrogen cooler ducts (400 x 570 mm), as provided in conventional THRI design (ref. Fig. 1). Therefore, it was decided to use devil nos Twin-coolers (ref Fig. 2&3). This concept has 2 nos. twin coolers determined in two separate cooler ducts. in operation(p) conditions of one cooler out of operation curb here also as in look of conventional 4 Nos. separate coolers. 4. 3.Changes in size of cooler and cooler ducts (550 x 650 mm) and duct fixture chaired in accession of width of stator body to 4200 mm from 4000 mm and height 4550 mm. Accordingly, stator body was redesigned completely maintaining routings of ribs, plates etc to follow the cellular respiration scheme of existing machine. Full continuance Foundation Support has been provided on stator in line with conventional GTGs. 4. 4. payable to the above mentioned increased dimensions of stator body, the seed is not suitable for rail transport (limit up to 4040 mm). indeed the generator stator shall have to be transported by road only.A dragging fixture has been designed and shall be welded to the bottom of stator frame to place it directly on the road trailer without requiring whatever additional fixture. It result also help placing the stator at any location without any keep or can be dragged at power station for erection, if required. 4. 5. It was proposed to use common Core convocation for GTG as well as STG for standardization and variety reduction. STG design required a power return of 261 MW. To produce the MCR rating it was decided to optimize the cellular respiration flow paths in the stator core.Number of ventilation ducts has been increased from 85 to 98 without any increase in the total core length. Width of the ventilation ducts was earlier a combination of 5 mm & 10 mm, which has now been changed to 5 mm, 8 mm & 10 mm (refer Fig. 4). In order to optimize electromagnetic performance of the machine, net iron length of core is maintained same. Modified ventilation electrical circuit vis-a-vis existing one is depicted in Figs. 5 & 6. 4. 6. Thickness of core ETS segments (Electro Technical make segments) has been increased from 0. 5 mm to 0. 65 mm without any loss in quality. T his will enhance the rigidity of core end zone packets.It will also increase the productivity and reduce core assembly time in shop by about 30%. 4. 3. Shifting of Terminal Bushings to the top of stator Frame, required redesign of Connecting Bus-bars and Arrangement of Terminal Bushing Connection Assemblies maintaining the air gap clearances(Fig-7). 4. 4. End Ring is introduced in this design for providing better rigidity in stator winding overhang. 4. 5. To make the generator suitable for static excitation system, new Slip Ring nib has been designed. Couplings of Slip Ring excavation have been redesigned to suit TG rotor (EE) at one end and Barring gear at the other end. 4. 6.In view of relocation of terminal bushings, drawings cerebrate to temperature and pressure monitoring circuits were prepared afresh. 4. 7. There is no availability of overhead cranes in Gas Turbine hall over Turbogenerator due to low ceiling of the building. This poses a major challenge for insertion of ro tor into stator. rotor coil weighs around 42 tons. So, a new carrier bag with Prime-Mover has been designed for Rotor Insertion in to Generator for GTG application. 4. 8. Design Documents (drawings and CBOMs) were sent to Corporate R & D for to carry out following calculations - (1)Static abridgment (a) Lifting of stator with 4 lugs b) in short Circuit Torque (c) hydraulic test at 10 bar (2) propulsive and Harmonic Analysis of Stator Frame with Core, Windings and rotor (3) Rotor Dynamics 4. 9. Generator Outline diagram for GTG is enclosed as Fig. 8. 5. RESULTS OF MECHANICAL CALCULATIONS 5. 1. Static Analysis Load ConditionsMaximum Stresses(N/mm? )Reference Lifting of Stator with 4 lugs110 Fig-9 Short Circuit Torque with 3. 5 bar internal pressure of Hydrogen238 Fig-10 Deformations of side wall due to hydraulic Pressure of 10 bar (fig-11) Locations on side wallDeformations (mm) TEEE 1700 mm above centerline1. 040. 46 1700 mm downstairs centerline0. 460. 40 5. 2.Dynamic and H armonic Analysis of stator with core & windings DirectionFrequency PeakReference Axial32. 3 HzFig-12,13 Vertical82 HzFig-14 Horizontal136 HzFig-15 6. TECHNOLOGICAL GAINS 8. 1. THRI bar type Turbogenerator has been developed for the first time for application with Gas Turbine. 8. 2. New design Stator can be placed directly on the trailer during imparting by road. It can be dragged at state of affairs during erection, if required. 8. 3. The new design of core is suitable for THRI STG design also due to improved ventilation. This will result in lower temperature rise leading to more(prenominal) reliable operation and enhanced life of the machine. . 4. systematisation and standardization of components has been interpreted into consideration to develop this design. Assemblies equal Rotor, End Shield, Winding bars, Terminal Bushings, Shaft Seals, vegetable oil Catchers etc will be used from that of existing design variant. 8. 5. Existing major tooling handle those for fabrication & machining of Stator Frame, assembly of core, Hydraulic and Pneumatic testing of Stator Frame will be used. 7. CONCLUSION THRI bar type Turbogenerator has been developed in-house for the application with Gas Turbine.With the design efforts of the team the design work was completed by 31st August, 2005. This new design has been approved by an external review team comprising of experts from IIT- Roorkee, Corp. R&D and RC Puram besides Haridwar experts from Technology, Quality & Engineering. Discussions were also held at PEM Delhi along with R. C. Puram for erection and maintenance of various Generator components like coolers, End Shields, Insert Covers, Rotor, Slip Ring Shaft Assembly and Bearings etc. New design features were explained and these were taken in to account for development of Power sow layout.