image

Turbine and Generator Repair

Turbine and Generator Repair



  • Turbines and Generators Repair and Overhauling Services
    • The Generator division of ATS provides comprehensive maintenance support including rewinding, repairing and overhauling works for all kinds of Generators and Turbines ranging from 5 to 1200 MVA. Furthermore, the division also has the expertise to work on Boilers, Turbines, Pumps, Condenser & Heat Exchangers.
    • These facilities are equipped with up-to-date technology and our skilled personnel are highly experienced, to guarantee our clients a repair and overhaul service for their equipment of an extremely high quality. We have technical support and supply agreement with most of the manufacturers and provide expertise for planning and supervision of machining and refurbishing activities.
    • With a best in the class facility and a team with strong technical prowess, alfanar Technical Services’ has maintained its prominence as the leader in providing reengineering services to clients across the MENA region.
    • In yet another recognition, ATS has now been qualified to provide repair, maintenance, rewinding and testing for Generators upto the capacity of 1200 MVA. With this qualification, ATS will be the only facility in the entire Middle East capable of providing such solutions in coordination with its partner workshop National Electric Coil, USA.
    • The qualification will also allow ATS to provide solutions both on site and in the workshop for Generator stators and rotors.
    ATS is now Middle East’s only SEC qualified facility to repair 1200MVA Generators

    Maintenance Solutions

    Condition Assessment

    ATS offers a complete range of test and inspection solutions for generators including life assessment and provide failure investigation and recommendation too. The test and inspection performed are linked to GAP - a solution for lifetime assessment of generators. GAP in turn is linked to the planned outage of the plant to maximize generator availability.

    Refurbishment

    Our refurbishment service includes minor & major overhaul, generator dismantling & reassembly, test & inspection, corona suppression treatment, stator rewedging, generator auxiliaries, etc. Most of the refurbishment activities are performed on-site.

    Repair and Spare Parts

    Our solutions for minor and major repairs for generators include, part winding repairs, supply of bars, stator rewind, rotor rewind, retaining ring replacement, high speed balancing, etc. Stator rewind and retaining ring insulation replacement can be performed on-site.

    Spare Parts

    Moreover, ATS can also supply all the spare parts for generator like bearing, hydrogen seal, gas cooler, slipring, carbon brush, diode, fuse, etc.

    Maximize availability & Reliability

    alfanar generator maintenance solutions ranges from basic recondition to complete rebuilds both in-house as well as on-site.

    image

    brief description of maintenance solutions offered is given below:

    Stator service includes

    • Stator partial rewind
    • Stator complete rewind
    • Stator re-wedging
    • Stator core re-stacking
    • End turns repair
    • Bar abrasion repair
    • Corona suppression
    • Bolt tightening
    • HV bushing change outs

    Rotor service includes

    • Rewind with old copper
    • Rewind with new copper
    • Rotor wedge replacement
    • Retaining ring removal
    • RR insulation replacement
    • Replacement of main leads
    • Winding distortion repair
    • Low speed balancing
    • High speed balancing

    Generator testing includes

    • Stator DC electrical test
    • Stator AC electrical test
    • Stator mechanical test
    • Stator core electrical test
    • Stator core mechanical test
    • Rotor DC electrical test
    • Rotor AC electrical test
    • Exciter test and inspection
    • Accessories integrity check

    Exciter service include

    • Test and inspection
    • Condition evaluation
    • Repair and refurbish
    • Rewinding
    • Diode integrity check
    • Fuse integrity check
    • Capacitor integrity check

    Spare parts supply includes

    • Collector rings
    • Bearings
    • Gas coolers
    • Carbon brushes
    • Stator bars
    • Retaining rings
    • Winding kit

    alfanar also offers a comprehensive maintenance services for mechanical equipment's like turbines, compressors, pumps, diesel engines like capital overhauling, refurbishment, balancing, dry ice cleaning and more.

    Generator Assessment Process (GAP)

    The life of a generator is mainly dependent on the life of its insulation. Therefore, the aging process of the generator must be very closely monitored. Just like the pulse rate, the blood pressure, sugar level etc., of a human are indicative of his health condition, the capacitance, leakage current, dissipation factor, polarization index, surge voltage with standing strength and partial discharge factors are indicative of the insulation condition of an electric rotating machine.

    Estimation of the remaining life of a generator is based on the following information:

    • The life history of the generator
    • A diagnostic evaluation of the generator's condition
    • The operation mode planned in the future

    On an average, the lifetime of the stator and rotor winding of a base loaded generator is about 35 and 25 years respectively. The lifetime will get reduced due to peak load or abnormal operating conditions. Other factors, such as, insulation abrasion, loose end-windings support and contamination may reduce the lifetime expectancy even more.

    alfanar Technical Services now offers GAP - a solution to lifetime assessment of generators - addresses the problems faced during the lifetime of a generator with an aim of increasing reliability and availability. Moreover, GAP is designed to perform generator assessment linked to the planned outage of the plant and thereby minimizing downtime.

    The past study and experience has shown that the availability of generator is determined largely by stator winding system, and thereby GAP methodology focus more on the stator winding compared to the rotor and other parts of the generator.

    4 levels of Generator Assessment Process


    GAP1 : 1-2 Days on-line Assessment

    Assessment based on historical, maintenance and operational data and of similar units. Perform thermal life assessment

    GAP2 : 2-3 Days Assessment

    GAP1 assessment with diagnostic tests in assembled condition. Assess healthiness of stator and rotor windings and perform diagnostic life assessment.

    GAP3 : 4-6 Days Assessment

    GAP1 and GAP2 assessment with rotor-in and partial dismantling. Perform visual examination and tests to the extent feasible. Life estimation.

    GAP4 : 5-7 Days Assessment

    GAP1 and GAP2 assessments with rotor-out. Perform ELCID, wedge tightness, bump, corona and other special tests. Perform condition and life assessment.


    Test & Inspection



    Unscheduled plant stoppages, whether caused by technical or human factors, result in loss of profitability. Generators and components that have reached end-of life status cannot continue safe and reliable operation - preventive maintenance actions and well-thought out asset management are keys to productive uptime and safety for people and the environment.

    alfanar offers a wide variety of test and inspection services that help to manage and optimize the life cycle of your generators.
    Together with our customers we can plan the best way to carry out test and inspection to get the following benefits:

    • Increase availability and reliability
    • Increase profitability by less unplanned downtime and minimal interruptions
    • Enhance safety
    • Gives you accurate information for maintenance plans and actions
    • Evaluate the condition of your generator and its components, identifies most critical parts
    • Helps you to manage assets more efficiently
    • Prevents accidents that can harm people and the environment

    alfanar has extensive experience in performing condition and life assessment on motors, generators and transformers in Middle East region and work together with the customer to ensure availability and reliability of the electrical machines.

    Dry Ice Blasting

    alfanar provides Dry ice blasting, which is a relatively new cleaning process using solid CO pellets. The pellets sublimate (convert 2 directly from a solid blast pellet to a vapor) leaving no residue. The process has grown considerably in popularity as a replacement for common sand blasting, largely due to its environmental and production benefits.

    Benefits

  • Decreased downtime through cleaning in-place
  • Faster and more thorough cleaning
  • Elimination of equipment damage
  • Reduction or elimination of solvents
  • Reduction in waste disposal
  • Increased safety
  • Stator Winding


    Before

    After

    Diesel Generator


    Before

    After

    Squirrel Cage Rotor


    Before

    After