Abstract: Introduces the pressure-holding test method of fire pipe in an UHV station. At the same time, for fire pipe that fail the pressure- holding test, the rapid and accurate detection and positioning of the fire pipe leakage points are described by combining the sectional sealing method. This paper analyzes the main causes of fire pipe leakage in UHV，at the same time，corresponding suggestions and solutions are proposed for the problems found during the test. Taking the pressure-holding test of a fire pipe in a UHV and the location of leakage points as an example，the leak detection results of the fire pipe of an UHV station indicate that the sectional sealing method can effectively and accurately detect all leak points of the fire pipe, ensure the safe and reliable operation of the fire fighting system of the whole station effectively.

Key words: UHV, fire pipe, pressure-holding test, leak detection, sectional sealing method