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With the ever increasing penetration of renewable energy, smart loads, energy storage, and new market behavior, today's power grid becomes more dynamic and stochastic, which may invalidate traditional study assumptions and pose great operational challenges. Thus, it is of critical importance to maintain good-quality models for secure and economic planning and real-time operation. Following the 1996 Western Systems Coordinating Council system blackout, North American Electric Reliability Corporation (NERC) and Western Electricity Coordinating Council (WECC) in North America enforced a number of policies and standards to guide the power industry to periodically validate power grid models and calibrate poor parameters with the goal of building sufficient confidence in model quality. The PMU-based approach using online measurements without interfering with the operation of generators provides a low-cost alternative to meet NERC standards. This paper presents an innovative procedure and tool suites to validate and calibrate models based on a trajectory sensitivity analysis method and an advanced ensemble Kalman filter algorithm. The developed prototype demonstrates excellent performance in identifying and calibrating bad parameters of a realistic hydro power plant against multiple system events.

As wind penetration increases in power systems around the world, new challenges to the controllability and operation of a power system are encountered. In particular, frequency response is impacted when a considerable amount of power-electronics interfaced generation, such as wind, is connected to the system. This paper uses small-signal analysis and dynamic simulation to study frequency response in power systems and investigate how Type-3 DFAG wind turbines can impact this response on a test power system, whose frequency response is determined mainly by a frequency-regulation mode. By operating the wind turbines in a deloaded mode, a proposed pitch-angle controller is designed using a root-locus analysis. Time simulations are used to demonstrate the transient and steady-state performance of the proposed controller in the test system with 25% and 50% wind penetration.

This paper proposes a solution for dynamic model validation and calibration leveraging measurement data. The proposed solution is designed to meet key engineering challenges associated with implementing a generic and scalable solution, and can work across multiple dynamic simulation engines with minimal exchange of information. A nonlinear least squares based parameter estimation formulation is considered and its benefits over some of the variants of Kalman filters are discussed. The efficacy of the proposed algorithm is demonstrated on realistic dynamic models of a variety of power plants and measurement data provided by NERC. Finally, an envisioned product implementation accounting for practical implementation challenges is presented.

With the continued development and proliferation of renewable energy systems worldwide, particularly wind and photovoltaic (PV) generation, computer simulation models for these technologies to be used in large interconnected power-system stability analyses have been a key focus over the past several years. Such computer simulation models are used by power-system planners and operators to simulate various scenarios of large interconnected systems?e.g., continental Europe and the western or eastern North American grid?to assess the stability and reliability of the bulk electric power system. In Europe, much of this work has been led by efforts within the International Electrotechnical Commission, while in North America, most of the major efforts in modeling has gone through the Renewable Energy Modeling Task Force (REMTF) of the Western Electricity Coordinating Council (WECC). The total nameplate capacity of wind generation installed worldwide has surpassed 360,000 MW, and PV generation has surpassed 130,000 MW, with the top three countries in terms of cumulative total capacity being China, the United States, and Germany.

The dynamics governing power systems are being modified by the continued increase in the installation of wind turbine-generators (WTGs). This paper presents a small-signal analysis on the impact of the power electronic interface of large quantities of wind generation have on the inter-area oscillation of a two-area system. In particular the sensitivity of this inter-area mode with respect to: (i) increased wind penetration, (ii) loading conditions in the face of wind integration, and (iii) the active and reactive power control parameters of a WTG are presented in this paper. The results show that wind integration increases the damping of this oscillation for most of the cases except when implemented in the area that is importing power.

The uncontrolled intermittent availability of renewable energy sources makes integration of such devices into today's grid a challenge. Thus, it is imperative that dynamic simulation tools used to analyze power system performance are able to support systems with high amounts of photovoltaic (PV) generation. Additionally, simulation durations expanding beyond minutes into hours must be supported. This paper aims to identify the path forward for dynamic simulation tools to accommodate these needs by characterizing the properties of power systems (with high PV penetration), analyzing how these properties affect dynamic simulation software, and offering solutions for potential problems. In particular, the system eigenvalue configuration of representative power system models is examined and how this configuration influences numerical integration scheme selection is discussed.

The power electronic grid interface of converter-based energy systems such as wind turbine-generators (WTGs) is modifying the dynamics governing power systems. For a fundamental understanding of the impact of power electronic interface on the electromechanical modes, that is, the synchronizing and damping torque on synchronous machines, this paper provides a small-signal analysis about the impact of WTGs on the local mode of a single-machine infinite-bus (SMIB) system. The main contribution is the incorporation of the WTG voltage control into the modal decomposition diagram of Heffron-Phillips and deMello-Concordia. Sensitivity coefficients are developed for the WTG voltage control loop and their impact on the real and imaginary parts of the local mode is illustrated with an example.

This paper describes generic models of photovoltaic (PV) systems developed for implementation in Western Electric Coordinating Council (WECC) base cases. The scope encompasses both transmission-connected, central station PV plants and distributed PV systems. These models were added to the WECC Approved Dynamic Model Library in March of 2014.