Technical Impacts of High Penetration Levels of Wind Power on Power System Stability

Abstract

With increasing penetrations of wind generation, based on power-electronic converters, power systems are transitioning away from well-understood synchronous generator based systems, with growing implications for their stability. Issues of concern will vary with system size, wind penetration level, geographical distribution and turbine type, network topology, electricity market structure, unit commitment procedures, and other factors. However, variable-speed wind turbines, both onshore and connected offshore through DC grids, offer many control opportunities to either replace or enhance existing capabilities. Achieving a complete understanding of future stability issues, and ensuring the effectiveness of new measures and policies, is an iterative procedure involving portfolio development and flexibility assessment, generation cost simulations, load flow and security analysis, in addition to the stability analysis itself, while being supported by field demonstrations and real-world model validation. Wind energy is being rapidly integrated into many power systems across the globe, with a total installed capacity of 370 GW, and with 51 GW added in 2014 alone 1. As the penetration of wind generation increases, the impact on power system dynamics is becoming increasingly apparent, and will become a more integral part of system planning and renewables integration studies 2. Historically, power systems have been based around large synchronous generators connected to a strongly meshed transmission network, with the dynamic characteristics of such systems being well understood. However, renewable generation, particularly in the form of wind and solar generation, is increasingly universally increased operational reserve requirement for wind power.

Including operational aspects in the planning of power systems with large amounts of variable generation: A review of modeling approaches

“…Power system stability is essentially a single complex problem, but as the system instabilities can occur in various forms, there has been a need for power system stability classification based on the main system variable where the instability can be observed and the size of the disturbance considered (Kundur et al, ). According to various case studies and observations reported in (Flynn et al, ), large VG shares may have an impact on all the main stability categories (frequency stability, voltage stability, and the two types of rotor angle stability: transient stability and small‐signal stability), but the impact is not necessarily always negative. Assessment of stability requires dedicated power system analysis tools capable of taking into account reactive power and performing dynamic simulations over a timeframe of seconds or minutes.…”

“…In addition, they may be connected to the distribution network or weaker parts of the transmission network, their control capabilities may be different from conventional generators, and their generation is subject to variability and uncertainty. Thus, large VG shares have an impact on the dynamic characteristics of power systems and consequently on power system stability (Flynn et al, ; Holttinen et al, ; Shah, Mithulananthan, Bansal, & Ramachandaramurthy, ).…”

“…While inertia levels and nonsynchronous share are convenient stability indicators at low VG shares, more sophisticated measures may be required at higher VG shares. These stability requirements also lead to interaction with curtailment levels (Flynn et al, ).…”

Wind power within European grid codes: Evolution, status and outlook

“…The likelihood and intensity of this occurring increases as the share of wind and solar power grows, and further HVDC connections are made to neighboring systems, unless additional measures are taken (Burtin & Silva, ; O'Sullivan et al, ). There can exist dynamic limits regarding the extent to which nonsynchronous sources (including photovoltaic generation and HVDC interconnections) can be used in synchronous systems, as they do not naturally provide (synchronous) inertia (Flynn et al, ). Fully converter‐based AC systems (all grid connected assets have power converter interface, no classical rotating electrical machines), where the grid frequency is not linked to the rotational speed of machines, remain a challenge today.…”

Shifting to clean energy—An editorial essay

“…With increasing shares of variable renewable electricity in the power system, new challenges are encountered due to the increasing mismatch between supply and demand. As noted by several articles published in Wiley Interdisciplinary Reviews Energy and Environment in 2017, this will require not only paying more attention to energy system integration issues, and developing new approaches and technologies for overcoming current barriers such as greater system flexibility (Flynn et al, ; Milligan et al, ), affordable energy storage (Lee, Kim, Yeom, & Kim, ), strategies to promote intersectoral coupling (Lah, ) and so on, but also putting new economic models and policies (Byrne, Taminiau, Kim, Lee, & Seo, ; Lah, ; Vogt‐Schilb & Hallegatte, ) into place, which will widen market development for rapid decarbonization.…”