Enhancement of power system stability in a deregulated environment-ASD-machines a promising alternative

In this paper, the application of adjustable speed hydro machines (ASH) has been discussed for enhancing power system stability in power networks. A direct comparison has been arranged between an ASH machine and a conventional synchronous machine. It has shown that by two dedicated rotor current regulators, the ASH machine is able to control the active and reactive power production quickly and accurately. The ASH concept represents an excellent possibility to get improved control with the network. With a more concise regulation, the power system may be utilised even better, still maintaining the necessary stability margin. This will also give an enhanced profitability for the generator owner. Furthermore, for these capabilities, being a part of the common term "ancillary services", there is a potential market growing up.