Starting from some pioneering papers in distributed parameter control systems for steam turbines and their auxiliaries, a bilinear model for steam turbines with steam extraction and "long" steam pipes was elaborated and the feedback control synthesis has been performed using a suitable control Liapunov functional of quadratic type, both for distributed parameters systems and their lumped parameter approximation. The synthesized control ensures global stabilization of the steady state solution. It has been observed much later that the linearized steam wave propagation equations underlying the model were in fact a simplified linearized version of the conservation laws of the isentropic flow. Following this remark and bearing in mind the recent advances in the control of the systems described by conservation laws, the model of the combined heat electricity generation is re-written as a system which is linear in control; consequently the feedback stabilization also requires re-examination.In 1946 an entire issue of an engineering journal was dedicated to the problem of the stability of some linearized feedback control systems in power engineering: it contained 3 papers written by two authors -an engineer and a mathematician -apparently before the war from where they did not return (Sokolov (1946), Kabakov (1946, Kabakov and Sokolov (1946)). Almost at the same time there were published other three papers on the same subject (Solodovnikov (1941), Aronovich (1948), Neimark (1948). The first ones dealt with thermal power engineering while the second ones with hydraulic power engineering. Nevertheless the approach had been the same -as the title of (Solodovnikov (1941)) says -the application of the Laplace transform and obtaining some characteristic equation whose roots needed to be localized in the left half plane of C. Later some of their models and results were integrated in monographs e.g. (Lurie (1950), Popov (1954) and the subsequent research followed.The examination of the mathematical models of the aforementioned papers indicates that they are based on similar models: the models contained the linear wave equation without losses describing lossless propagation of steam or water over long pipes or galleries. The dynamics of the power devices -water or steam turbines -were oversimplified, described by linear ordinary differential equations like the control structure based on the mechanical controllers and sensors of that time. A special mention has to be nevertheless made for (Kabakov (1946)) where the deduction of the model starts from the hyperbolic partial differential equations of the isentropic flow which are nonlinear; they are however linearized from the very beginning ⋆ The research has been supported by the Project UEFISCDI-ROMANIA PN-II-ID .(and with some omission) but the starting point is useful to be known.The models have been "re-discovered" due to the fact that the characteristic equations involved there contained terms of the form e −τs thus pointing to some possibly associated equations with delayed ...