210 / 2022-03-14 18:53:01

Simulation Research on Temperature Rise Characteristics of 252kV Transformer Bushings

bushing,temperature rise,finite element simulation

Purpose/Aim

Transformer bushing is an important part of power transmission equipment, abnormal temperature rise will lead to the deterioration of bushing insulation and affect the safe and stable operation of power system. For this reason, it is of great significance to study the temperature characteristics of bushings under normal and overload conditions.

Experimental/Modeling methods

In order to clarify the temperature distribution characteristics of the bushing under normal and overload conditions, a simulation study on the temperature rise of a 252kV bushing is conducted in this paper. First, the heat generation and heat transfer characteristics of the bushing are analyzed theoretically, the distribution of heat sources is clarified, and the processes of heat convection and heat conduction in the bushing are analyzed. Secondly, a 252kV, 1250A bushing temperature rise simulation model is established, the setting scheme of heat source is discussed, and the characteristics of bushing temperature distribution and oil flow distribution are studied. Finally, the simulation study of bushing temperature rise under different overload currents was carried out, and the axial temperature distribution of the central conductor and the relationship between bushing temperature and hot spot location with input current were summarized.

Results/discussion

1) The temperature distribution of the bushing under excitation of rated current shows that the temperature of the lower part of the flange is higher, and with the increase of height, the temperature inside the bushing gradually decreases. The hot spot is on the surface of the central conductor on the underside of the flange, which temperature is 73.6°C.

2) Under rated conditions, the maximum oil flow rate is 0.16m/s, which appears in the cavity of grading shield.

3) With the increase of input current, temperature of the central conductor increases gradually, and the hot spot position moves to the flange side, the hot spot temperature is linearly related to the current.

Conclusions

In this paper, on the basis of analyzing the heating and heat transfer characteristics of transformer bushings, a temperature simulation model of a 242kV, 1250A oil-impregnated paper bushing is established, the temperature distribution and oil flow characteristics of the bushing under normal working condition are studied. Temperature distribution of the central conductor under overload currents of 1.05IN, 1.1IN, 1.15IN and 1.2IN is analyzed.