my country's power grid is developing rapidly, and it is a key industry supported by the country's "Twelfth Five-Year Plan". The power transmission and transformation industry is facing a once-in-a-lifetime development opportunity, and the demand for GIS equipment will increase in the future. The metal compensator for GIS is one of the key equipment of large-scale power switchgear in the future, and will also have a very broad market application prospect and huge economic value and social significance.

In recent years, the reliability and stability of high-voltage switches, especially gas-insulated fully enclosed switchgear (GIS), have been continuously improved. The form of metal compensator for GIS is also diverse with the specific application environment of its power grid pipeline, and the requirements for materials are also more stringent. The research and development of composite metal compensator for GIS with different materials for each layer has become a general trend. The life estimation of the compensator for composite GIS is the top priority of the reliability and stability construction of the power grid.

Calculating the pressure of each layer of bellows of the metal compensator is the key to calculating the stress of each layer of bellows caused by the pressure. The gap between the two layers of tube blanks is about 0.15mm. Due to the small gap between the layers, the strain of the bellows in all directions is almost the same.

When the pressure is 0.845Mpa, only a single-layer stainless steel metal bellows can meet the pressure resistance requirements, so even if the A199.6 layer is not enough pressure-resistant, if one more layer is added, the overall pressure-resistant capacity will still be improved, so the composite metal compensation The device can meet its withstand voltage requirements.

The calculation formula in the standard can only calculate the life of the multi-layer bellows of the same material, but cannot calculate the life of the compensator conforming to the two materials. In order to calculate the life of the composite compensator according to the standard formula, the life of a single layer of a certain material can be calculated. If the life of each layer meets the requirements, the overall life will meet the requirements.

The fatigue life of the composite metal compensator inner layer stainless steel 321 calculated by the life formula is 11429.1 times, and the fatigue life calculated by the software is 64800 times. It can be seen that the safety factor of the life calculated by the standard formula is larger, which is 5.67 times larger than that of the calculation software. The fatigue life of the outer layer A199.6 is 1.72X105 times. If the safety factor is increased by 5.67 times, its life value is also 30335.1 times. It can be seen that the life of the composite metal compensator meets the predetermined life requirement of 10,000 times.

For the life of the composite metal compensator, the life of each layer of corrugations can be evaluated individually. The key is to understand how each layer of corrugated pipes shares the internal pressure. The stainless steel layer is calculated according to the life formula of conventional GB/T12777-2008, A199.6 cannot be calculated according to the life formula, and its fatigue life is analyzed by finite element analysis.

Now this type of compensator is in trial production, and it has its particularity for welding and forming of aluminum materials. After the trial production is completed, we will carry out type test, type test evaluation and theoretical life evaluation of theoretical calculation and finite element analysis of the composite compensator, which will greatly improve the stability and reliability of the composite compensator after it is put into use.