Trans-regional transmission of large-scale hydropower: problems and solutions in receiving power grid

Abstract Large-capacity hydropower transmission from southwestern China to load centers via ultra-high voltage direct current (UHVDC) or ultra-high voltage alternating current (UHVAC) transmission lines is an important measure of the accommodation of large-scale hydropower in China. The East China Grid (ECG) is the main hydropower receiver of the west-east power transmission channel in China. Moreover, it has been subject to a rapidly increasing rate of hydropower integration over the past decade. Currently, large-scale outer hydropower is one of the primary ECG power sources. However, the integration of rapidly increasing outer hydropower into the power grid is subject to a series of severe drawbacks. Therefore, this study considered the load demands and hydropower transmission characteristics for the analysis of several major problems and the determination of appropriate solutions. The power supply-demand balance problem, hydropower transmission schedule problem, and peak- shaving problem were considered in this study. Correspondingly, three solutions are suggested in this paper, which include coordination between the outer hydropower and local power sources, an inter-provincial power complementary operation, and the introduction of a market mechanism. The findings of this study can serve as a basis to ensure that the ECG effectively receives an increased amount of outer hydropower in the future.