Nowadays, more and more converters are interconnected in face-to-face with each other to achieve higher power and equivalent switching frequency. This interconnected-converter system appears in advanced testing benches for power electronics, paralleled-connected converters, or open winding motor drive systems. Typically, the interconnected converters are powered by the same dc voltage source, and thus inevitably creating zero-sequence current path in the ac terminals. Consequently, undesired current harmonics, which do not exist in typical 3-phase 3-wire converter systems, are introduced, with increased power loss and extra stresses. These current harmonics have complicate frequency spectrum under different mission profiles, which have significant impacts on sampling results. However, these impacts of the current harmonics are seldomly discussed. In this article, the time-domain models of the high-order zero-sequence current harmonics in an interconnected-converter system are established under various operating conditions. Impacts of the high-order zero-sequence current harmonics, including current waveform distortions, sampling distortions and control errors, are comprehensively identified and analyzed, which can help to predicate the current waveforms and eliminate the impacts of the current harmonics from more aspects. Simulations and experiments are provided to validate the analysis.