Judgment Standard for Insulation Aging of Generator Stator Winding

As the top generator set manufacturer in Taizhou, Starlight Power Generation Equipment has a professional production technology and has carefully studied and analyzed the various performances of the generator. Next, we will introduce the judgment standard, identification method and test period of insulation aging of generator stator winding.

Criteria

1. The cumulative operation time should generally exceed 30 years (for those with poor manufacturing process, the time can be appropriately shortened).

2. During the operation or preventive test, the insulation breakdown fault occurs many times, even the test cycle is shortened, and the test standard is lowered, but the safe operation cannot be guaranteed.

3. During appearance and dissection inspection, aging phenomena such as serious void of insulation layer, poor curing, loss of integrity, serious partial discharge and insulation damage between strands were found.

Identification method

1. During the qualification test, the insulation qualification test of the whole phase winding shall be carried out first, which can generally be carried out in the hot state after shutdown. If the insulation breakdown occurs during operation or maintenance, and the whole phase winding test fails, the sampling test of a single bar shall be carried out.

2. The quantity of single bar sampling test is: for steam turbine generator, it shall not be less than 4%~5% of the total number of bars; For hydro-generators, it shall not be less than 1%~2% of the total number of bars. However, the number of bars selected shall not be less than 6, and the selected position shall be based on the upper layer of bars, and the different operating potentials of bars shall be considered.

3. During insulation aging identification, comprehensive analysis shall be conducted on the generator overload and over temperature operation time, causes and treatment of previous accidents, problems found in previous maintenance and test conditions, so as to evaluate the insulation operation condition.

4. Where it is necessary to replace all insulation, the Electric Power Test and Research Institute shall put forward an appraisal report and submit it to the competent provincial power bureau (or power grid bureau) for approval. The units with capacity of 100MW and above shall also be submitted to the Department of Power of the Ministry of Energy for filing.

Test cycle

Insulation aging identification test shall be carried out in case of insulation breakdown during operation or preventive test for a long time (generally the accumulated operation time is more than 20 years).

During the first overhaul after the new machine is put into operation, the stator winding insulation can be subject to non-destructive test for comparison and analysis in the future.

Jiangsu Starlight Power Generation Equipment Co., Ltd. is an early professional manufacturer of generators and diesel generator sets in China. The company has first-class national-level large-scale production and load testing equipment. Provide users with long-term diesel generator set sales, leasing, technical consultation, commissioning, maintenance, training services and generator set trusteeship business. If you would like to get more information welcome to contact us via sales@dieselgeneratortech.com.