Background: The article describes a device for simulating defects for use with acoustic control systems for high-voltage transformers. Aim: experimental research of a mobile device for imitation of power transformer defects; determine the parameters of impulses simulating various insulation defects Methods: development of technical means for imitation of insulation defects; experimental research; determination of parameters of signals simulating defects. Results: a block diagram of a device for imitating defects is shown; experimental studies of the device for imitating defects were carried out; the power of pulses simulating various defects in the insulation of high-voltage transformers was calculated. Conclusion: The proposed device generates high-voltage pulses that simulate various defects in the insulation of high-voltage transformers. The parameters of acoustic signals are given.