Now showing 1 - 9 of 9
  • Publication
    Real-time System-wide Inertia Estimation in Power Systems with High Wind Penetration Levels
    Knowledge of on-line inertia in power systems with high and increasing levels of wind penetration is becoming more important for power system operators. In this paper, the basis of a real-time stored energy estimator is developed, which accounts for the inertia contribution from loads as well as generators in the system. By creating a simplified first order model of the system, power and frequency signals recorded are utilized to estimate real-time feeder stored energy by use of a linear least-squares estimator. The capability of the proposed estimator is investigated by application on a test system. The estimation error is analysed in respect of data resolution and feeder contributions to stored energy. Discussion on the requirements for applications within power systems and the communication configuration are also presented.
  • Publication
    Stochastic power system operation
    This paper outlines how to economically and reliably operate a power system with high levels of renewable generation which are stochastic in nature. It outlines the challenges for system operators, and suggests tools and methods for meeting this challenge, which is one of the most fundamental since large scale power networks were instituted. The Ireland power system, due to its nature and level of renewable generation, is considered as an example in this paper.
  • Publication
    Renewables Integration, Flexibility Measures and Operational Tools for the Ireland and N. Ireland Power System
    (Société de l'électricité, de l'électronique et des technologies de l'information et de la communication, 2016-12-21) ; ;
    The Ireland and N. Ireland power system is pursuing ambitious renewable energy (mainly wind generation) targets for 2020. A range of system-wide initiatives are being developed as part of the DS3 (Delivering a Secure, Sustainable Electricity System) programme, and, in particular, a bespoke suite of ancillary services incentivising fast frequency response, dynamic reactive power and ramping margin, and other, (future) system needs. With approximately half of the wind generation connected at distribution level, network development at both distribution and transmission levels is a key challenge for both the transmission system operators (TSO) and distribution system operators (DSO): a wide range of technical options are being examined, including undergrounding, HVDC connection and series compensation, supported by a public and stakeholder engagement programme. The experience gained is highlighted, while also indicating solutions and strategies which have been proposed, and ongoing challenges for the future.
  • Publication
    Emulated Inertial Response from Wind Power: Ancillary Service Design and System Scheduling Considerations
    Worldwide, variable-speed wind turbine and solar photovoltaic generation are displacing conventional power plant in market schedules. Committing out-of-merit conventional units to redress system synchronous inertia or primary frequency response shortfalls incurs start-up and production costs, and may also engender additional greenhouse gas emissions and wind/solar curtailment. In order to ensure that future system frequency response requirements are met in a low carbon manner, new sources of frequency stability ancillary services will need to be incentivised or mandated via grid codes. Nonsynchronous devices (batteries, flywheels, variable-speed wind turbines), with appropriate control architectures, can provide a fast frequency response following a system disturbance, i.e. a temporary injection of active power, supplied faster than existing primary frequency response deployment times. Operational considerations relevant to transmission system operators when designing a fast frequency response ancillary service are presented, particularly if sourced from wind power emulated inertial response. It is shown that careful consideration regarding the design of fast frequency response characteristics is required in high wind power systems: the system frequency response behaviour may be degraded if a holistic approach to fast frequency response design is not taken. A method to characterise the system-wide (aggregate) emulated inertial response from wind power is presented, which can be integrated as a form of fast frequency response within unit commitment and economic dispatch. Endogenous incorporation in unit commitment and economic dispatch ensures that non-synchronous fast frequency response sources do not only supplement existing fossil fuel-based spinning reserve provision, but also reduce the need to commit synchronous generators for frequency control reasons. However, given the inherent energy recovery/payback experienced by variable-speed wind turbines providing emulated inertial response when operating below rated output, it is imperative to consider the impact of such negative power trajectories on system primary frequency response requirements.
  • Publication
    Operational security at high penetrations of stochastic, non-synchronous generation
    As levels of stochastic, non-synchronous renewable generation (wind, wave and solar) significantly increase, system operators are faced with many new operational challenges. Consequently, there is a growing need to create flexible operational strategies based on near-real-time system assessment. This paper presents an outline of the operational challenges arising from stochastic, non-synchronous generation, as well as the tools which can be used to cost-effectively enhance operational security.
      363Scopus© Citations 3
  • Publication
    Incorporating Line Security Constraints within Network Planning for Dynamic Line Rating Systems
    In order to maintain system security levels against a backdrop of generation and demand growth, network planners may require grid expansion and/or line modification measures. Traditionally, this has been achieved by uprating existing lines and constructing new lines. However, technical, environmental, cost and timeliness concerns can encourage the adoption of dynamic line rating (DLR) systems, as part of enhancing the utilisation of the existing network. Hence, a novel approach is presented here for planning reconductoring and DLR systems, relating to the implementation of security constraints. A multi-year stochastic mixed integer linear model for line N-1 short time security is developed, incorporating a unit commitment stage, which is later solved using Benders decomposition. An additional pre-optimisation stage, which can be efficiently parallelised, is introduced to largely support the burden of incorporating the security constraints. In addition, staged investments for individual lines, including applying DLR before later reconductoring, is investigated. The effectiveness of the proposed approach is shown for the IEEE RTS 24 bus system.
      14Scopus© Citations 3
  • Publication
    Improved system operations with high penetration of wind power : a dialog between academia and industry - Ireland
    This is a submission to a panel session at the 2010 IEEE PES General Meeting. It discusses effective collaboration between academia and industry.
  • Publication
    Enhancing network utilisation in wind-rich regions using coordinated dynamic line rating, energy storage and power flow control schemes
    Increasing wind energy utilisation, along with demand growth, are impacting on transmission system regional loading. Traditionally, uprating of existing lines and construction of new lines would have been common approaches to increase network capacity and reduce congestion. However, environmental, social, and technical challenges are encouraging network operators to apply measures which improve utilisation of the existing network, as part of future planning. Here, a mixed integer linear programming model is developed to integrate various alternative options, including dynamic line rating, energy storage systems and distributed static series compensation, into the network planning process. Using a multi-stage approach, co-optimised planning of these assets is studied and compared against a conventional reconductoring approach. The benefits of cooptimisation are shown for the IEEE RTS 24 bus system, with high wind contributions in selected regions.
    Scopus© Citations 1  11
  • Publication
    Load inertia estimation using white and grey-box estimators for power systems with high wind penetration
    (Elsevier - International Federation of Automatic Control (IFAC), 2012-09-02) ; ; ;
    The increasing penetration of wind farms in power systems has increased concerns over the frequency behaviour and control of synchronous power systems due to a low contribution from modern wind turbines to overall system inertia. With this trend of conventional generators being displaced by variable speed wind turbines, the contribution from load inertia becomes more significant. The need for greater consideration towards load inertia estimation, or even on-line tracking of load inertia, seems to be required. A white-box method for estimation of load inertia is examined using system frequency and generator output power signals from previous generator forced outages. A grey-box identification method is also applied to estimate the inertia of synchronous generators. The impact of sampling rates, time shifting and signal averaging on parameter estimation is also considered. The method is shown to be robust enough to be applied for load inertia estimation in control centres.
      1001Scopus© Citations 24