Abstract: Wind turbines can provide Primary Frequency Reserve (PFR) through overspeed control to improve power system frequency stability. However, the existing research concerning reserve optimization, on the one hand, does not fully describe the Decision Dependent Uncertainty (DDU) of PFR provided by wind power through overspeed control and the physical constraints associated with rotor speed decision, which may result in a model that does not adequately reflect the actual operating conditions of the wind turbine; on the other hand, it does not fully consider the dangerous operation area of wind turbines under the influence of Induction Generator Effects (IGE), which may lead to sub-synchronous oscillations during the actual operation of the system, threatening the safe and stable operation of the system. Based on these two problems, this paper analyzes the DDU of wind power providing PFR, puts forward the definition of prohibited rotor speed zone and analyzes its impact on wind power PFR. On this basis, a frequency-constrained wind and thermal power coordinated reserve optimization model is established considering DDU and prohibited rotor speed zone. Based on the analysis of two cases, the positive effects of wind power providing PFR in improving system frequency stability and operation economy and the necessity to consider prohibited rotor speed zone are verified.