Comparisons of Damping Controllers for Stability Enhancement of an Offshore Wind Farm Fed to an OMIB System Through an LCC-HVDC Link

Modeling and Analysis of an LCC HVDC System Using DC Voltage Control to Improve Transient Response and Short-Term Power Transfer Capability

“…2 also shows that ΔIdcr and ΔVdci in (2) and (3) can be calculated using ΔVdcr and ΔIdci of the DC line. Using the equations for Δα, Δγ, ΔIdcr, and ΔVdci provided in Appendix A, (2) and (3) can be converted to (4) and (5), which are expressed in the frequency domain s. By using additional equations to express the differentials of H, Y, U, and Z (see Appendix B), (4) and (5) can be divided into multiple first-order differential equations, which are in a matrix form as: (6) This procedure is comprehensively explained in Appendix B. From (6), the state space model of the LCC HVDC system with the proposed control method is represented by:…”

“…These maximum and minimum limits of the converter controller gains were determined based on previous studies [27]- [29], while ensuring the stabilized variation in Vdcr and Idci for the full operating range of the converters. In [27]- [29], HVDC systems were modelled using the rated DC voltage and power similar to those of the test HVDC system in this paper: i.e., Vdc_rated = 184 kV and Pdc_rated = 150 MW. Note that optimizing the converter controller gains is beyond the scope of this paper.…”

A Review on Impacts of Wind-Solar Hybrid Generation System on Low Frequency Oscillation of Power System

“…Study on the influence of photovoltaic permeability on the static stability, small disturbance stability and transient stability of interconnected power transmission networks in [16], in view of the large-scale photovoltaic centralized access, from the voltage, power angle and frequency, include so many aspects in [17], the influence of large scale photovoltaic power grid on power system stability is analyzed.…”

Review of technologies for DC grids – power conversion, flow control and protection

“…Renewable power generation has increased substantially in all major developed and developing countries, presenting significant challenges to grid operators at generation, transmission and distribution levels. Some of these challenges can be summarised as follows [1][2][3][4][5][6] • Wide spread uses of HVDC links and wind generators with fully rated back-to-back converters deprive ac grids from the contribution of the generators' rotating inertias to damping of low frequency power oscillations following major ac network disturbances. • Intermittent nature of renewable energy resources exacerbates the problems of power balance and poor utilization of the ac lines due to undesirable power flow in ac power systems with high penetration of renewable power generation.…”

“…Renewable power generation has increased substantially in all major developed and developing countries, presenting significant challenges to grid operators at generation, transmission and distribution levels. Some of these challenges can be summarised as follows [1–6]: Wide spread uses of high‐voltage dc (HVdc) links and wind generators with fully rated back‐to‐back converters deprive ac grids of the contribution of the generators’ rotating inertias to damping of low‐frequency power oscillations following major ac network disturbances. Intermittent nature of renewable energy resources exacerbates the problems of power balance and poor utilisation of the ac lines due to undesirable power flow in ac power systems with high penetration of renewable power generation. Operation of power electronic‐based solar and wind generators, which are less sensitive to frequency variation (±2.5 Hz) alongside the frequency sensitive large conventional synchronous generators, render most existing protection philosophies inadequate. This is because the stability margins of the latter dictate the overall stability of the entire power system, leading to unnecessary loss of generation or tripping of conventional power plants due to loss of synchronism. Some of these challenges could be addressed with well‐designed smart grids that employ both ac and dc transmission systems with state‐of‐arts control and communication systems, where the vast energy stored in the dc lines and converters’ cell capacitors of the asynchronous connections could be manipulated to mitigate the effect of renewable energy resources variability on power quality, and improve transient stability by splitting large ac power systems into several independent asynchronous ac protection zones in order to prevent ac fault propagation throughout the system [4, 5, 7].…”