English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Tools annual

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

Back-to-Back (B2B) HVDC systems can enhance cross-regional transmission capacity and overall power system stability. However, their use in interconnecting two extremely weak grids can compromise system stability. This paper presents a comprehensive stability analysis of a B2B HVDC system to distinguish the root causes of instability mechanisms and identify the critical short circuit ratio (CSCR) of each converter station under inverter and rectifier operations considering the impact of power feedforward compensation of the dc-bus voltage controller. The study also investigates the stability implications and CSCR changes when a dc transmission line connects the converter stations, creating a point-to-point (P2P) HVDC system. Eigenvalue analysis, based on detailed small-signal modeling, showed that three distinct instability mechanisms, high-, low-, and medium frequency instabilities, can compromise the operation of VSC stations under extremely weak grid conditions. Notably, the medium-frequency instability observed in the P2P HVDC system during inverter operation is predominantly caused by the power feedforward compensation of the dc-bus voltage controller. Furthermore, the analysis reveals that the CSCRs for dc-bus voltage-controlled VSC stations are higher in comparison to power-controlled ones. This suggests that a dc-bus voltagecontrolled VSC is more susceptible to instability in weak grid scenarios than its power-controlled counterpart. Active compensators are designed based on participation factor analysis to mitigate the identified instabilities. The findings are validated with extensive simulations and real-time hardware-in-the-loop tests, demonstrating the analysis&#x0027;s accuracy and the proposed compensators' efficacy.

ieee open journal of power electronics

Comprehensive Analysis and Stabilization of a B2B HVDC System Connecting Two Extremely Weak Grids Considering the Impact of Power Feedforward Compensation