The direction of power flow in high penetration microgrid is frequently uncertain, which directly leads to the working mode of generalized electric spring including critical section line impedance is far more than that of traditional electric spring. Based on the concept of generalized electric spring proposed in this paper, the operating boundary of generalized electric spring is analyzed according to circuit theory, and its compensation ability to network fluctuation is discussed. Combined with the power grid background of Single-end Power Supply and Dual single-end Power Supply for critical section feeder, 64 working modes of generalized electric spring are discussed by using phasor diagram.

generalized electric spring; critical segment feeder; microgrid