• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2005년도 제36회 하계학술대회 논문집 A
• /
• pp.641-643
• /
• 2005

It is usual to operate the long transmission line with transposition of each phase in order to avoid voltage unbalance due to unbalanced capacitances at each phase of the line end. This paper described the Ferranti voltage rise of line end, charging current and secondary arc current according to the transposition of line or not. The positive and negative sequence current was derived by the phase current, and then the unbalanced rate was calculated. Then, we obtained the reclosing dead time of the single phase reclosing scheme for 500 kV single circuit horizontal arrangement transmission line system.

• Journal of Power Electronics
• /
• 제18권4호
• /
• pp.1223-1234
• /
• 2018

In this paper, a new three-port multidirectional DC-DC converter is proposed for integrating an energy storage system (ESS) to a bipolar DC microgrid (BPDCMG). The proposed converter provides a voltage-balancing function for the BPDCMG and adjusts the charge of the ESS. Thanks to the multi-functional operation of the proposed converter, the conversion stages of the system are reduced. In addition, the efficiency and weight of the system are improved. Therefore, this converter has a significant capability when it comes to use in portable BPDCMGs such as electric DC ships. The converter modes are analyzed and small-signal models of the converter in each of the independent modes are extracted. Finally, comprehensive simulation studies are carried out and a BPDCMG laboratory prototype is implemented in order to verify the performance of the proposed voltage balancer using the burst mode control scheme.