Power System Dynamic Performance Committee

The structure of the Subcommittee is a mix of Working Groups and Task Forces, addressing the various technical areas within the scope of the Subcommittee.

Working Group on Power System Dynamics Measurements
(Chair: Mani Venkatasubramanian)

Development of procedures, methods and techniques for detecting, recording, and analyzing power system dynamic performance, for use in system controls, for event reconstruction, for validation of correct operation of equipment, controls, and protection, and for developing and improving simulation models. The Working Group will consider transducers, computation equipment and algorithms, communications, and other portions of systems for these measurements. The Working Group will disseminate its results appropriately, including use of panel sessions, technical paper sessions, and preparation of papers. The Working Group will coordinate its activities with other IEEE and CIGRE bodies, including the Power System Relaying Committee and the Power Systems Instrumentation and Measurements Committee.

Working Group liaisons:

• • Power Systems Instrumentation and Measurements Committee - Harold Kirkham
  • Power System Relaying Committee - Gary L. Michel

Working Group on Dynamic Performance of Renewable Energy Systems
(Chair: Juan Sanchez-Gasca)

Study and evaluate renewable energy technologies related to power system stability and control; provide a forum for the analysis and discussion of matters related to renewable energy systems; foster dissemination of pertinent information. The topics of interest to the Working Group include: development of dynamic models for renewable energy systems and components, design and analysis of renewable energy system controllers, impact of renewable energy systems on power system dynamic performance, analysis of interactions between renewable energy systems and other power system components, simulation software, and VAR management.

Task Force on Oscillation Source Location
(Co-Chairs: Qiang (Frankie) Zhang and Udaya Annakkage; Secretary: Ning Zhou; Webmaster: Kai Sun)

Oscillation monitor has discovered many "new" oscillatory behaviors that could not be reproduced through traditional model based analyses. Operators have a strong need to identify the sources and damp the oscillations. This TF has four tasks: 1. Test Cases Library: The TF will add more simulated and real PMU data cases to the existing library (http://web.eecs.utk.edu/~kaisun/TF/testcases.html). 2. Summarizing Approaches: The TF will summarize, evaluate and compare the different approaches used for oscillation source analysis. 3. Theoretical Investigations: The TF will review the latest oscillation source theories and reach consensus, as well as define related concepts and terminologies. 4. Online Algorithm Development: The TF will evaluate and test several most promising online oscillation source location algorithms using the developed test library, and also work with academia, vendor and utility companies to develop production grade tools. The TF will work closely with NERC to push for the first "killer app" for the PMU data.

Task Force on Power System Restoration with Renewable Energy Sources
(Chair: Martin Braun)

The Task Force analyzes the present situation and elaborates improvements that guarantee a secure and fast restoration with a high share of renewable energy. Important issues include inverter control, handling of generation dynamics, communication, distribution islands/microgrids, HVDC links etc.

Task Force on Modeling and Simulation of Large Power Systems with High Penetration of Inverter‐based Generation
(Chair: Antonello Monti)

Provisional Scope: The modeling of inverter-based generation has been an area of intense effort for the past ten to fifteen years. The computer simulation models available for these generation technologies presently may be categorized into four main categories: 1. Detailed vendor-specific proprietary electromagnetic transient (EMT) type models; 2. Simplified vendor-specific proprietary EMT model (i.e. reduced models including only the most relevant controls for a specific types of studies); 3. User-written vendor-specific proprietary RMS/positive-sequence models for stability analysis; and 4. Generic, public and standard RMS/positive-sequence models for stability analysis. There are continued industry efforts in developing all of these various categories of models. The first three are clearly developed by the vendors through internal resources and/or working with third-party model developers. The last category has been, and continues to be, developed by two main industry efforts. The Western Electricity Coordinating Council’s (WECC) Renewable Energy Modeling Task Force, and the International Electrotechnical Commission’s (IEC) TC88 WG27. These efforts are ongoing, and particularly, under the WECC REMTF effort continues to be made to update and enhance the models by introducing additional modules to the modular model structure to facilitate modeling new and emerging features in these technologies, and to enhance the features of the models. In general, the first two types of models referred to above are developed and used in EMT-software platforms such as PSCADTM, EMTP-RV, MATLAB® Simulink® Simscape Power Systems Toolbox and other similar tools. On the other hand, the latter two model structures are typically developed and used in positive-sequence simulation platforms such as Siemens PTI PSS®E, GE PSLFTM, PowerWorld Simulator and PowerTech Labs TSATTM. There are of course other simulation platforms (e.g. DigSilent PowerFactory) which offer an ability to combined both RMS models and 3-phase phasor domain models. Moreover, more recent developments allow one to interface positive-sequence tools with EMT tools such that portions of the system are modeled with detailed EMT level models, while the remainder of the system is developed in a positive sequence model. What this Task Force will endeavor to accomplish is to document the following: 1. What each category of models can be used for and there limitations and their strengths; 2. Where each of these model categories are applicable and more effectively used; 3. What are the boundaries of application of each type of modeling tool, i.e. positive-sequence, versus phasor-based versus EMT modeling, and what opportunities may be present to extend the limits of applicability of the former tools; 4. On-going R&D efforts in extending the limits of applicability of the various simulation strategies, and creating better interfaces across the simulations tools (e.g. hybrid-simulation, standard dll interfaces, etc.); and 5. An understanding of the dynamic performance of the inverter-based technologies and emerging control strategies and thus the need for evolving models and modeling platforms to keep up with the technological advancements. The above discussions should of course cover the ability/suitability of each of the various models/software-platforms/simulation techniques to adequately model all the key aspects of inverter-based generation dynamic performance, including (i) voltage/reactive control and response, (ii) control interactions, (ii) fast-frequency response and primary-frequency response, (iii) low/high voltage and frequency ride-through, (iv) voltage-current characteristics of the converter interface (e.g. blocking of the power electronics under severe fault conditions), etc.

Task Force on Measurements, Monitoring, and Reliability Issues Related to Primary Governor Frequency Response
(Chair: Howard Illian)

This Task Force should identify and make recommendations for resolving some of the issues identified in the IEEE Special Publication 07TP180, "Interconnected Power System Response to Generation Governing: Present Practice and Outstanding Concerns", May 2007, as they relate to primary frequency regulation. The risk to security, assumed to be adequate due to present levels of Primary Governing Frequency Regulation (PGFR) by expert judgment, should be confirmed by technical analysis. The following question should be answered: If some portions of an interconnection require greater PGFR due to their topology and risk of separation, how does this greater PGFR affect reliability when the interconnection experiences a disturbance and remains intact? Can imbalances in PGFR result in increased risk during disturbances? In addition, the TF should make recommendations on possible ways of performing on-line monitoring to estimate the governor steady-state droop and response of turbine-generator governor action.

Link to the Final Report

Task Force on Contribution to Bulk System Control and Stability by Distributed Energy Resources connected at Distribution Networks
(Chair: Nikos Hatziargyriou)

The task force seeks the contribution of Distributed Energy Resources (DER) connected at the distribution network to the control and stability of the bulk transmission system. Control can be basically exercised by exploiting the power electronic converter used to interconnect most type of DER. Since DER are mostly inertialess or decoupled from the distribution network, power electronics are used to mimic the behavior of traditional thermal machines using equivalent "droop" techniques. Similarly, support of voltage/reactive power is possible. The TF will provide an overview of control techniques for DER and their capabilities to provide frequency and voltage control to the transmission system also considering the characteristics of distribution networks.

Link to the Final Report

Task Force on Benchmark Systems for Stability Controls
(Chair: Rodrigo Ramos)

The task force seeks to establish a limited number of benchmark systems that represent current best practice in damping controller tuning. The group will focus on optimally tuning widely known systems. The concept of optimality is not well defined, but intuitively relates to maximizing small- and large-disturbance damping performance subject to robustness and practicality trade-offs. The criteria used to establish optimality for each system will be documented. Applications of these systems include: a) Certifying control design procedures and tools, b) Benchmarking new controllers and control techniques.

Link to the Final Report

Link to the Transactions Paper

Task Force on Microgrid Control
(Chair: Claudio Canizares)

An important part of the proper integration of Distributed Generation (DG), and in particular inverter-based resources, to the grid is the control of DG units within microgrids during grid connection, islanded operation, and the transition between those two modes. The coordinated integration, operation and control of microgrids is of particular relevance for the successful realization of active grids. This Task Force will concentrate on the study of control issues such as frequency and voltage control of microgrids, as well as the interaction and coordination of these controls with the integrated grid controls.

Link to the Final Document

Task Force on Power System Restoration Dynamics
(Chair: Nelson Martins)

The impact of a blackout exponentially increases with the duration of the blackout. There are many factors that impact restoration time, including problems with restoration dynamics. The restoration duration is significantly reduced with the availability of initial sources of power. There are several protection and control mechanisms that help retain critical sources of power during power system degradation. The TF addressed several of the following automatic and manual restoration issues with a dynamics and control perspective: load rejection, low-frequency isolation, controlled separation, standing phase angle (SPA), estimating restoration duration, operator training simulators with better dynamic models, generator reactive capability (GRC), minimum-source requirement, remote black-start, asymmetry issues, restoration analytical tools, increased use of automatic controls, and others.

Link to the Final Document