22_rita _maintenance rot machines.pdf

Reinsulation Rotor Generator and Repairing of Flexible Lead

GTG 2.1 Tambak Lorok Combined Cycle

By . Embun K Rita Triani

Dwi Handoyo

Background

The unit was prepared for charging the bus bar A. After finishing its, they has loss voltage. That caused by a capacitive load received by the generator.

1.

Making Electrical and Mechanical test, It founds that the value of the rotor winding and insulation resistance is infinite. By using the boroscope it founds that flexible lead of generator are broken

2.

Drawing of Collector end of Generator Field

Scope of Work

Rotor Winding assy & Diss asy a. Disconnect

Interpole Connection, Spacer Block and Wedges

b. Dismantling Bar Coil

c. Assembly Bar Coil

d. Assy Flexible Lead

Fabrication a. Flexible

Lead b. Material

Insulation

Evaluation and Analysis

Peformance Test after unit

Syncron

Fabrication Flexible Lead and Material Insulation

Flexible Lead Fabrication

1. Preparing tools for flexible lead

2. Preparing Material flexible lead

3. Manufacturing plate flexible lead

4. Brazing plat flexible lead

5. Repairing isolator flexible lead

6. Ultrasonic Test brazing Flexible Lead

7. Contact Resistance Test brazing of Flexible Lead


The weight of the two side flexible leads should be approximately equal in order to avoid the mass unbalance during operation. The manufacturing process of flexible lead is performed with quality control as follows. a. Quality control of Cu material test of copper plate Cu material

composition (99 % Cu). b. Quality control of brazing preformed brazing procedure specification

(WPS) c. Quality control of brazing result nondestructive test (Ultrasonic test ,

megger test and contact resistance) Manufacture of flexible lead was adjusted with dimensions required by considering aspects as follows. a. Electric current-carrying capability, a primary function of flexible leads. b. The mechanical strength is able to hold centrifugal force when the

generator rotor operates. From the whole set of material selection, manufacturing and testing, then the flexible lead is ready to be installed on the generator rotor.

Re-Engineering Flexible Lead


Material Insulation Fabrication 1. Preparing tools for insulation profile

2. Preparing Material insulation

3. Manufacturing insulation profile

4. Monitoring and testing insulation profile

Evaluation and Analysis

MEASUREMENTS

Standard of Measurement EASA AR 100 – 2010

(Recommended practice for repair of rotating electrical apparatus)

1. Insulation resistance test ( megger )

2. Winding resistance test (tools micro ohm meter programma )

3. Surge comparison test ( surge test, tools D12R )

4. Voltage drop test ( dc or ac voltage ) coil in series

( ac voltage test )

5. Checking and testing sistem AVR excitation System

6. Recurrent Surge Ocillograph ( RSO )

7. Rotor Temperature Sensitifity ( RTS )

Measurement Results

Performance Test After Unit Syncron

CONCLUSION

1. The reinsulation and replacement of flexible lead can be done through a careful material selection and method that used in the Overall. Material insulation is using NOMEX class while for flexible lead using material Cu 90% .

2. Parameter Quality is based on std EASA AR 100-2012 3. Re insulation and replacement of flexible lead can be

performed by several steps including its quality testing method. Until now, the generator of Gas Turbine 2.1 can operate normally.

Recommendation

1. Always monitor the operating parameters of the generator rotor to avoid the force outage. The parameter as follows : Vibration, MVAR, temperature, excitation current and etc.

2. Always operate the power plant on its capability curve, to

minimize the risk of rotor generator breakdown.

22_rita _maintenance rot machines.pdf

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