Motor‐generator pair: novel technology to transmit stable and high‐quality power for power system with high penetration of renewable energy

Abstract

With the increasing penetration renewable energy, some changes are transforming the power system dynamic characteristics, resulting in new stability issues. One of the issues is the lack of inertia and damping. One is sub-synchronous oscillation (SSO) caused by inter-harmonics associated with inverter-based renewable power generators (IPRG). A novel technology is proposed to transmit stable and high-quality power for power system with high penetration of renewable energy. Thus, the object of this paper is synchronous motor-generator pair (MGP) system, a new gird-connection device, which is proposed to solve above problems. First, the two mass block shaft model of MGP is established, which verifies the small signal stability of this system, and it has high damping that can be controlled flexibly. Then, the harmonic response of MGP is analysed through the internal electromagnetic relationship. Result shows that comparing with the input power from renewable energy sources to M side, the harmonic content of output power on G side is greatly reduced, especially the even harmonic. These characteristics are verified by experiments. So transmitted by MGP, the power quality and stability are greatly improved.