Surge Tank Stability under Distributed Parameters

The paper considers the stability analysis of the surge tank in hydroelectric power plants, in the case of elastic upstream water column i.e. with distributed parameters tunnel. The model is obtained as a special case from a rather general hydroelectric plant structure with distributed parameters of the water flow along the conduits. The stability of the linearized model is discussed using the stability of an associated system of neutral functional differential equations via the classical results on Hurwitz quasi-polynomials obtained by N. G. Čebotarev and N. N. Meyman. Application of these results leads to an improved Thoma inequality containing a safety factor larger than 1.