Power and frequency control in the national power system of the 370 MW coal fired unit superstructured with a gas turbine

A very important task of power units with high power capacity is their participation in the control of the national power system. One of the most important questions posed at work is whether a 370 MW power unit superstructured with a gas turbine in parallel and a heat recovery steam generator be able to take part in the national power system control and if such an upgrade will be economically effective. The analysis was carried out using a proprietary and novel mathematical model. The model takes into account, among others, the influence of the ambient temperature on the parameters of the gas turbine and the changes in thermal steam parameters at its steam extractions as a result of load changes. The results of the analyses showed that it is possible for the modernized unit to participate in the power system control. It can be done only by using a gas turbine with a variable power and a shut off option. The presented results of economic calculations show that at price and cost levels assumed for calculations, the turbine gas superstructure is at the threshold of viability and the investment carries a high degree of risk.