Jose R. Gracia

Frequency Regulation and Oscillation Damping Contributions of Variable-Speed Wind Generators in the U.S. Eastern Interconnection (EI)

The U.S. Eastern Interconnection (EI) is one of the largest electric power grids in the world and is expected to have difficulties in dealing with frequency regulation and oscillation damping issues caused by the increasing wind power. On the other side, variable-speed wind generators can actively engage in frequency regulation or oscillation damping with supplementary control loops. This paper creates a 5% wind power penetration simulation scenario based on the 16 000-bus EI system dynamic model and developed the user-defined wind electrical control model in PSSE that incorporates additional frequency regulation and oscillation damping control loops. The potential contributions of variable-speed wind generations to the EI system frequency regulation and oscillation damping are evaluated and simulation results demonstrate that current and future penetrations of wind power are promising in the EI system frequency regulation and oscillation damping.

Variable-speed wind generation control for frequency regulation in the Eastern Interconnection (EI)

The United States Eastern Interconnection (EI) might go through some profound changes due to the increasing penetration of wind power in this bulk grid, including the worsening of the frequency response. However, the fast response speed of electronic converter devices makes it possible that the kinetic energy stored and/or wind power reserve (if it exists) in variable-speed wind generation could be injected into the power grid in a fast manner. This portion of fast, injected active power could contribute to frequency regulation of the EI significantly if implemented with appropriate control schemes. This paper introduces the basic theories of fast active power control techniques of variable-speed wind generation. This paper then describes a user-defined wind electrical control model with fast active power controllers built in PSS/E. Based on the 16,000-bus EI system dynamic model, a dynamic case with realistic penetration of wind power is created. Taking advantage of the user-defined wind electrical control model, the potential contribution of variable-speed wind generation to the EI system frequency regulation is evaluated. Simulation results demonstrate that current and future wind generation sources are promising in providing frequency regulation in EI system.

Oscillation damping contributions of variable-speed wind generators in the Eastern Interconnection (EI)

The United States Eastern Interconnection (EI) might go through some profound changes due to the increasing penetration of wind power in this bulk grid, such as the worsening of inter-area oscillations across the interconnection. However, the fast response speed of power electronics devices makes it possible for properly-timed electrical power from variable-speed wind generators to be injected into the power grid. These electronics devices can be controlled in a fast manner and, thus, can significantly contribute to oscillation damping if implemented with appropriate control schemes. In this paper, a user-defined wind electrical control model with a wind oscillation damping controller is built in PSS®E. Then a dynamic case, with realistic penetration of wind power, is created based on the 16,000-bus EI dynamic model. Taking advantage of the user-defined wind electrical control model and EI system dynamic model, the potential contribution of variablespeed wind generators to the EI system oscillation damping is evaluated. Simulation results demonstrate that, at current and future penetration levels, wind generators represent a promising tool for damping oscillations in the EI.

Wide-area power system frequency measurement applications

Synchronized phasor measurements can reveal important insights about the health and stability of the power grid in near-real time. Unfortunately, the high cost associated with the installation of phasor measurement units (PMUs) has limited their adoption in the electric utility industry. The Frequency Monitoring Network (FNET) was created to provide low-cost, high-accuracy frequency and voltage phase angle measurements from the 120-V distribution level. Using widely-deployed Frequency Disturbance Recorders, FNET provides a system-wide view of the grid that is unavailable anywhere else. This paper describes the physical structure of the FNET system, as well applications that make use of its data.

Design of a large-scale virtual power grid for research community

Due to security and liability concerns, the research community has limited access to realistic large-scale power grid models to test and validate new operation and control methodologies. It is also difficult for industry to evaluate the relative value of competing new tools without a common platform for comparison. This paper proposes to develop a large-scale virtual power grid model that retains basic features and represents future trends of major U.S. electric interconnections. The proposed model will include realistic power flow and dynamics information as well as a relevant geospatial distribution of assets. This model will be made widely available to the research community for various power system stability and control studies and can be used as a common platform for comparing the efficacies of various new technologies.

Wind/PV Generation for Frequency Regulation and Oscillation Damping in the Eastern Interconnection

This report presents the control of renewable energy sources, including the variable-speed wind generators and solar photovoltaic (PV) generators, for frequency regulation and inter-area oscillation damping in the U.S. Eastern Interconnection (EI). In this report, based on the user-defined wind/PV generator electrical control model and the 16,000-bus Eastern Interconnection dynamic model, the additional controllers for frequency regulation and inter-area oscillation damping are developed and incorporated and the potential contributions of renewable energy sources to the EI system frequency regulation and inter-area oscillation damping are evaluated.

Impact of measurement errors on synchrophasor applications

Data from phasor measurement units (PMUs) inform powerful diagnostic tools that can help avert catastrophic failures in the power grid. Because of this, understanding PMU measurement errors is particularly valuable. This paper examines internal and external factors contributing to PMU phase angle and frequency measurement errors and gives a reasonable explanation for each. Based on these explanations, the impact of those measurement errors on several synchrophasor applications are analyzed: event location detection, oscillation detection, islanding detection, and dynamic line rating.

Contribution of Variable-Speed Wind Generators to Frequency Regulation and Oscillation Damping in the United States Eastern Interconnection

The United States Eastern Interconnection (EI) has been going through some profound changes due to the increasing penetration of wind power in this bulk grid, including the worsening of the frequency response and inter-area oscillation. However, the fast response speed of electronics devices makes it possible that the kinetic energy stored and/or wind power reserve (if it exists) in variable-speed wind generators could be injected into the power grid in a fast manner. This portion of fast-injected active power could contribute to frequency regulation or oscillation damping of the EI significantly if implemented with appropriate control schemes. In this chapter, a user-defined wind electrical control model with fast active power controllers is built in PSS®E. Then, based on the 16,000-bus EI system dynamic model, the potential contributions of variable-speed wind generators to the EI frequency regulation and oscillation damping are evaluated respectively. Simulation results have demonstrated that current and future penetrations of wind generation are promising in providing frequency regulation and oscillation damping in the EI.