A Novel Operation of Regional Power Grids in China: The Generator Voltage-Class-Reduction Scheme

Abstract

Considering the generator voltage-class-reduction operation will affect the security and economics of the power systems, this paper proposed a method to analyze the feasibility of the voltage-class-reduction scheme. The paper includes two parts: one analyzes the short-circuit current changes in the scheme, and then the mathematical relationship between the short-circuit current changes in low-voltage side transformer bus and the generator parameters was established; the other part analyzes the economics of the scheme from the point of view of power loss in power line and transformer, and it tries to establish relationship between the power loss and the distance of the unit's outgoing line. From this paper, it can be concluded that the short-circuit current analysis model we proposed is more concise and has similar results compared with traditional simulation software. The paper also points out that there is an economic equilibrium point between economic benefits and the distance of the power line in the generator voltage-class-reduction operation, and within which the scheme is feasible and economical.

Keywords

• Generator units
• voltage-class-reduction operation
• power system planning
• short-circuit currents
• economics