Economic Analysis of Thermal Power Plants Considering Hidden Costs in Deep Peak Shaving

Because the high wind power penetration rate in power system increases the volatmty of the net load curve, thermal power units (mainly coal-fired units in China) frequently participate in deep peak shaving to consume excessive wind power. But hidden costs such as wear-and-tear cost, combustion supporting cost and environmental cost during deep peak shaving will increases, which will influence the operating economy of coal-fired units; on the other hand, pumped storage hydropower stations (PHS) in China usually pumping and generating according to the peak and valley period of the conventional load forecast curve, without fully exploiting their peak-shaving ability. This paper first establishes peak-shaving costs model of coal-fired units with plasma ignition (CPI) based on operating characteristics analyzed for three peak shaving periods. Then an economic dispatch model considering maximizing wind accommodation is proposed and the operating economy of CPI considering hidden costs during deep peak shaving is analyzed. Results show that economy of CPI in deep peak shaving is greatly reduced. Based on the results, a CPIPHS coordinated operation scheme in deep peak shaving is proposed and its peak-shaving ability is studied. Results demonstrate that proposed scheme could improve wind power and PHS utilization and effectively reduce peak-shaving costs of thermal power plants.