A series flywheel architecture for power levelling and mitigation of DC voltage transients in multi‐terminal HVDC grids

Abstract

This study proposes a new architecture of flywheel energy storage system (FESS) which can be implemented at generating unit (GU) level (e.g. wind turbine) or scaled up for application in grid-side converter (GSC) stations of a multiterminal direct current (MTDC) system. The proposed architecture suppresses DC voltage leaps under grid faults, and performs power levelling duty at grid connection points. When implemented at GU level, the proposed FESS features a doubly-fed induction machine (DFIM) -the flywheel machine -where its six stator winding terminals are connected in series between the grid and the GSC. The flywheel converter is of partial power rating, and is connected to the DFIM rotor. When employed at an MTDC GSC station, several submodules are connected to build an FESS station. The study proposes the control concept and the general topology of the FESS station. The performance parameters of the system are tested under normal and abnormal operating conditions. Results and analyses indicate smooth dynamic operation, the economic advantage and the improved fault ride-through capability because of the proposed system.

A critical review of research trends for wind energy in Egypt: recent progress and promising opportunities

“…Gowaid et al (2013) investigated issues related to brushless cascaded DFIG WT such as gear reduction, operation under unbalanced grid voltage and compliance to grid code in terms of fault ride-through capability. Gowaid et al (2014) suggested an architecture for flywheel energy storage system for DFIG WT. Abdel-Rahim et al 2014introduced a WECS with a multiphase power generation and a matrix converter controlled via model predictive control.…”

Modelling of high‐power hybrid DC circuit breaker for grid‐level studies

“…DC circuit breakers (CBs) have not traditionally been used at transmission levels since almost all the voltage-source converters high-voltage, direct current (VSC-HVDC) systems have been developed as point-to-point systems [1][2][3][4]. A DC fault in a point-to-point HVDC can be isolated by tripping the AC CB at both terminals.…”

“…Recently however, there has been growing interest in developing DC transmission grids [1][2][3][4]. DC grids are becoming very attractive when multiple HVDC are being installed in close proximity.…”

Modeling and Control of a Low-Speed Flywheel Driving System for Pulsed-Load Mitigation in DC Distribution Networks

“…However, they entail sophisticated technologies to reduce friction and their power output is limited by cost and difficulty of cooling [13]. A variety of machines have been discussed in the literature for use in low speed flywheel applications including induction machines (IM) [14]- [16], [9], and Doubly Fed Induction Machines (DFIM) [13], [17]- [21]. In [22], the control and performance of a large DFIM based flywheel was investigated.…”