Estimation of resource capabilities of the NPP turbine unit under the primary frequency control of the current in the power system

Abstract

The purpose of the article is to estimate the life cycle on the example of NPP with the K-1000-60/1500 turbine and with the VVER-1000 reactor under cyclic load changes using the primary frequency control. The criterion for estimating the life cycle is the rate of the fatigue crack growth of the most loaded rotor element. The main requirements for the NPP power units under conditions of involvement in the primary frequency control are provided. The cyclic loading of the NPP turbine unit blades under conditions of maintaining the power reserve due to a reduction in the load by 2% by throttling the steam, and in line with the requirements for participation in the primary frequency control by 8% of the nominal capacity is substantiated. At the same time, the cyclic mechanical and thermal stresses are determined for the HPC and the LPC rotor blades. In this regard, it is shown that the first stage blades of the HPC rotor during unloading by 8% of the nominal capacity of the most cyclically loaded. The loading intensity and the rate of the fatigue crack growth of the first-stage blades of the HPC rotor are determined on the basis of the cyclic crack-resistance methodology and the Paris equation. It is shown that the rate of the fatigue cracks growth is negligible which determines their longterm life cycle.