The paper presents a local quasi-one-dimensional theory of steady state current generation in tokamaks by lower hybrid waves which is valid for an arbitrary width of the wave spectrum. The characteristics of the generation of current drive in large scale tokamaks are analysed. On the basis of the concepts developed here, expressions are derived for the total driven current, the absorbed RF power and the global current generation efficiency. The dependence of the current generated by lower hybrid waves on the plasma parameters is investigated.