— The paper proposes a technique to accurately and efficiently locate periodic steady-state solutions of electric power systems. This technique is based on an enhanced version of the time-domain shooting method (TDSM) and the probe-insertion technique (PIT). The latter has been successfully applied to low-power electronic circuits but it is innovative for the study of electro-mechanical steady-state periodic behaviour of power systems. With this aim, the paper discusses the inherent criticalities of the conventional formulation of power system models (PSMs). Then, a novel formulation is proposed to accommodate the hypotheses and mathematical requirements of the TDSM and PIT. The effectiveness and numerical efficiency of the proposed model and technique are discussed through two case studies based on the IEEE 14-bus and WSCC 9-bus systems.