RELIABILITY OF OPERATION OF POWER TRANSFORMERS

Ilhomjon Qodirov

Authors

 

Petrova R.M. – postgraduate student, Department of Power Supply of Industrial Enterprises, Kazan State Power Engineering University, Kazan, Russia, 1998renata@mail.ru

 

Annotation

 

 The article describes the reliability of transformers, the failure rate and uptime to the first failure, the durability and maintainability of transformers and their service life, the allowable temperature rises and the dependence of steady-state overheating on the load factor of the transformer. An assessment of the influence of the ambient temperature on the rated power of the transformer is given. Dependences of heating on the changing load of transformers are given. The heating time constant is calculated depending on the power and cooling system of the transformer. The winding heating temperature is considered for real daily load schedules of a 33/11 kV transformer, the maximum actual overheating at full power loading is compared with permissible overheating. These studies can be applied to other transformers with subsequent interpolation of values. In conclusion, it is noted that the value of systematic overloads is determined by two conditions: the thermal wear of the insulation with a changing load should be the same as with a long-term constant winding temperature at the most heated point; the highest oil temperature in the upper layers and the hottest winding point during the transient daily heating process is not higher than 95 and 140 degrees, respectively. Emergency overloads are allowed in exceptional cases, for example, when one of the operating transformers fails.

 

Key words

 

transformer, reliability, failure rate, uptime, overload, short circuit current, transformer substation, rated power

 

References

 

  1. Gracheva, E.I., Sadykov, R.R. Study of probabilistic characteristics of power supply systems. Izvestiya vuzov. Energy problems. 2017. No. 1-2.
  2. Petrova, R.M. Analysis of the reliability of electrical equipment of workshop networks // Proceedings of the conference of the XVII All-Russian Open Youth Scientific and Practical Conference “Dispatching and Control in the Electric Power Industry” (October 20–22, 2022) / Editorial Board. G. Arzamasova (responsible editor). – Kazan: LLC “Foliant”, 2022. – Р. 206-209.
  3. Petrova, R.M. Investigation of the reliability characteristics of power transformers / R. M. Petrova, E. I. Gracheva // Problems and prospects for the development of energy, electrical engineering and energy efficiency: materials of the VI Intern. sci.-tech. conf. – Cheboksary: Chuvash Publishing House. un-ta, 2022. – Р. 201-205.
  4. Sadykov, R.R. Formation of models for assessing the operational reliability of intra-factory power supply systems / E.I. Gracheva, R.R. Sadykov // Vesti of higher educational institutions of the Chernozem region. Power industry. 2017. No. 1(47). P.1–10.
  5. Sadykov, R. R. Application of an analytical method for calculating the reliability of elements of power supply systems based on probabilistic models / E.I. Gracheva, A.R. Safin, R.R. Sadykov // Reliability and safety of energy. No. 1(36). pp. 48–52.
  6. Secretary, Yu.A., Levin, V.M. Assessment of the impact on the reliability of the power supply system of various kinds of defects in its main elements. Vestnik KSEU. 2019. No. 4 (44).
  7. Petrov, T.I., Safin A.R. Theoretical aspects of optimization synchronous machine rotors. E3S Web of Conferences. 2020.

 

Publication date

2023-10-27