After a short-term trial operation

the inlet piping of low temperature reheater of a newly-built 300 MW thermal power unit deviates widely

and the support-hangers are seriously crushed and overloaded. In order to explore the mechanism of pipeline linear deviation

load test of the installed constant support-hangers was carried out

it showed that large load deviation and constant degree exist in the support-hangers. The static simulation calculation of the pipeline indicated that the cold vertical displacement after the trial operation is basically consistent with the measured value

the primary stress of the pipeline in this state exceeds the allowable value

and the thrust and push torque of the end point increase sharply. The analysis shows that

there are many factors leading to the pipeline deviation of power piping

among which the mismatch between the support-hanger loads and the piping weight is the most critical one

which is caused by the large constant degree and load deviation of the constant hanger. The structural characteristics of the constant support-hanger determine that it can not maintain constant output load between the cold and hot state. It is suggested that in the design of the power piping

the arrangement of support-hangers on the pipeline should be optimized as far as possible

and the purchase and daily maintenance of support-hangers should be strengthened in the management and supervision.