Calculation and Site Tests on Artificial Grounding Experiments of UHVDC Transmission Lines

The artificial short circuit test of transmission lines is one of the important steps for debugging of HVDC transmission projects. It plays an important role in assessing the ability of handle faults of DC systems, verifying the sequence of line fault recovery process, and checking fault location ability of the lines. This paper describes the basic method of short circuit test of the ±800kV UHVDC transmission line in China Southern Power Grid (CSG), and studies the selection of the copper wire for artificial grounding experiment of transmission lines, simulates the short-circuit currents under various operating conditions. The influence and distribution of the step voltage on the surface of the testing area is studied and the safety distance for testers is proposed. The study found that the calculated ground current and the actual measured value are not very different, and the calculation results can be used to guide the design of artificial short-circuit test. According to the simulated short-circuit current, the cross-sectional area of the copper wire is recommended to be 1.0mm
²
. The site tester's personnel safety distance of at least 30m away from current injection location is suggested. And insulated boots and gloves are always recommended to put on. The research method in this paper can be used for the preparation and development of artificial grounding tests for UHVDC transmission projects.