The article covers the study of emergency situations in the work of semiconducting compensator. The authors considered potential impact of emergency situations, determined the main emergency modes that may arise in the system "industrial supply mains - static semiconducting compensator - load", and showed the basic ways of prediction of system behavior under the emergency conditions and boundary conditions close to the emergency. A single-phase power supply of contact AC machine for spot welding used in the automotive industry when manufacturing the body parts in mechanical engineering is considered to be an example of electro-process load in the system. The authors performed a simulation modeling in the Matlab Simulink system. The article presents and describes the diagram of electrical system computer model, describes mathematical expressions for calculation of compensating current. The authors give the simulation results in the form of flow diagrams in the absence of compensation, in normal operation of compensating device, and in emergency modes: short-circuit in the load, short-circuit in the semiconducting switch of the compensator voltage inverter, at idle load, and at no-load of inverter switch of compensator voltage. The article presents the ways of protection of compensator and its load in such modes, and makes the conclusions about the possibility of their processing using the facilities of compensator management system. The authors prove the necessity of joint use of such traditional protection facilities as circuit breakers under the conditions of short-circuit in the load. The article describes possible behavior of the control system of compensating device for safe processing of short-circuit of one inverter voltage switch, as well as the modes of no-load or compensator switch.