Capacity credit for multiple wind farms and dynamic programming based optimal power flow for wind turbines with various designs.

摘要

Over the last six years wind power has become the most rapidly growing renewable energy utilized in electricity generation in the United States. Wind power has been playing an important role in power production due to both being environmentally clean and its successful integration into the power systems.;During the course of the study presented here, thirty-one 60-meter-high wind measurement towers were installed in eastern Wyoming and western Nebraska by the researcher, his colleagues, and local ranchers in order to secure first-hand wind data. Inhouse tools were developed in order to analyze the wind data and produce monthly and year-to-date reports for the sponsors. This dissertation shows the average wind speeds, hourly wind speed curves, wind rose, and capacity factors of some of the thirty-one towers.;There are three main electrical configuration types of wind turbines: wind turbines with induction generator; wind turbines with doubly-fed induction generator; and wind turbines with direct drive; and each was modeled in this dissertation. The voltages, real power and reactive power of the three types of wind turbines were simulated and compared during a three-phase ground fault. The rotor speeds of the induction generators, the rotor angles of the synchronous generators, and their angular stability were also analyzed. Next, the wind farm was connected to the IEEE 30-bus and 57-bus test systems, and the simulation showed that the voltage stability of the system in steady state was improved after the integration of the wind power. Finally, the system transmission loss and the voltage stability indicators were calculated, using conventional optimal power flow and adaptive dynamic programming. The system transmission loss and the voltage stability indicator of adaptive dynamic programming were determined to be better than those of conventional optimal power flow because adaptive dynamic programming optimized the system during the whole study time period, while conventional optimal power flow only optimized the system at the particular time it was being used.;According to the simulation, additional generation resources were shown to increase the power system voltage stability. Integrating wind power can supply extra power to the power system. However, wind power is intermittent and wind farms cannot provide "firm" power, as conventional power plants usually do. During the peak load demand time, if wind power penetration is high, the shortage of power reserves for contingencies might occur due to low wind speed. Therefore, wind power is awarded zero or low capacity credit, which is an important component of the income for generation resources. In this dissertation, the wind power availability and capacity credit of one individual wind farm and the combination of four wind farms were compared and analyzed using the wind data collected over the course of the study. The results showed that the wind power availability and capacity credit were increased if multiple wind farms were considered together as one big wind farm distributed over a large geographical area.