Jingyuan Dong

Wide-area Frequency Based Event Location Estimation

This paper discusses the latest developments in wide-area frequency-based event location using FNET. FNET, meaning ldquoInternet based frequency monitoring networkrdquo, is a low cost and quickly deployable wide-area frequency measurement system with high dynamic accuracy. This project demonstrated the feasibility of using information from FNET to estimate the location of events in the electric grid. An on-line real time event detection tool using least squares methods was developed and tested on data from FNET. This paper outlines the methods used along with an examination of implementation feasibility.

Analysis of Power System Disturbances Based on Wide-Area Frequency Measurements

It is very important to understand system dynamics during disturbances in order to improve control measures to ensure power system security and reliability. Power system disturbances are examined in this paper based on wide-area frequency data from a nation-wide frequency monitoring network (FNET). Frequency characteristics of events in three major North America power grids are investigated. Typical frequency patterns of generation loss and load drop events are analyzed for Eastern Interconnection system, Western Electricity Coordinating Council system, and Electric Reliability Council of Texas system. The recovery patterns following disturbances are also studied to evaluate control performances of the interconnections.

Monitoring power system disturbances at the distribution level

Wide-area measurement systems (WAMS) enable the monitoring of bulk power systems providing deep insight into system dynamics. The North American frequency monitoring network (FNET) takes GPS-synchronized wide-area measurements in a low-cost, easily deployable manner at the 120 V distribution level. A situational awareness system has been implemented on the server located at Virginia Tech to detect and analyze power system disturbances in near-real time. This paper discusses several major disturbances in Eastern Interconnection (EI) observed by FNET. Important parameters of power systems, such as frequency, voltage and phase angle, are examined to understand system behavior during disturbances. The recordings and analysis show that a great deal of valuable information about dynamics in transmission systems can be obtained at a lower voltage level.

Wide area synchronized measurements and inter-area oscillation study

The Frequency Monitoring Network (FNET) provides a low-cost, easily deployable method for wide-area monitoring. FNET has the capability to realize long term, high density and continuous monitoring of large interconnected power systems. In effect, there are potentials for ground-breaking research on wide-area monitoring and control. In this paper, low frequency oscillations in the Eastern Interconnection (EI) are analyzed based on generation trips detected by FNET in 2007. The oscillation data were selected in a way such that their locations are distributed throughout the EI system. In addition, some preliminary statistical analysis of the dynamic characteristics is presented. Through illustrating the control method of system stability, it is shown that the analysis of oscillation mode shape distribution is very important. As an example, some preliminary simulation results are provided for the control of system low-frequency oscillation due to transmission line faults or other changes in system topology.

Development of TVA SuperPDC: Phasor applications, tools, and event replay

With information and measurement technology evolving rapidly within the electric power industry, wide-area measurement, monitoring and control (WAMC) is deemed to be the key technology to improve power system reliability. Guided by this vision, the North American SynchroPhasor Initiative (NASPI) is a nation-wide project that collaborate various resources to build the infrastructure of WAMC across North American. As part of NASPI, Tennessee Valley Authority (TVA) is developing super phasor data concentrator (SuperPDC) which is the infrastructure hosting different measurement resources and providing platform for numerous WAMC applications, both real-time and none real-time. This paper outlines the SuperPDC architecture and demonstrates some real-time and close to real-time applications, developed by TVA and Virginia Tech based on SupersPDC platform.

Power system frequency oscillation characteristics

This paper reports the initial results on low frequency oscillation monitoring and analysis combining practical measurements from an Internet-based frequency monitoring network (FNET) and simulations. Typical oscillation characteristics excited by various disturbances are shown using simulations and real measurements. The corresponding time-space dynamic propagation patterns are also provided. The frequency domain characteristics are also provided revealing oscillation modes and damping factors.

Analysis of power system disturbances based on distribution-level phasor measurements

The Frequency Monitoring Network (FNET) takes GPS-synchronized wide-area measurements in a low-cost, easily deployable manner at the 120V distribution level. It has been monitoring the North American power grid since 2004. Various advanced situational awareness tools have been added using FNET data. Examples include disturbance alert, event location triangulation, oscillation detection, and a number of real-time visualization tools. Power system disturbances characteristics in North American power grid is examined in this paper based on FNET captured events from 2009 to 2010. Further, this paper investigates system dynamics during several major disturbances in Eastern Interconnection and Western Interconnection captured by FNET in 2010.

Visualization of wide area measurement information from the FNET system

Analysis of power system dynamics helps to understand the operation of a power system. Therefore, it is significant to design and develop advanced visualization tools to interpret frequency, voltage magnitude, and phase angle information so that it can be presented to the operators in an intuitive manner. On the basis of the measurement data collected by widely-distributed frequency disturbance recorders (FDRs), visualization tools have been implemented for the FNET system. A number of FNET visualization tools are discussed in this paper, including real-time visualization, animated event replay, visualization of oscillation mode analysis and visualization of propagation effects in two dimensional systems. These tools correlate the FDR measurements with their corresponding geographical information, and transform the combined matrices into different graphic formats using various computer techniques and programming languages. The graphics generated by these tools facilitate power system operation by allowing an operator to monitor power system dynamics, perform post-event analysis and identify modal oscillations more efficiently.

Detection of the start of frequency excursions in wide-area measurements

This paper addresses the on-line estimation of the start of frequency perturbation in power systems using dynamic data measured across distribution networks. These measurements are provided by Internet based real-time, GPS synchronized, wide-area frequency monitoring network (FNET) and PMU data in WECC. In this paper the collected data are evaluated with current statistical model and adaptive tracking algorithm to detect the frequency perturbation of the power system. The goal is to automatically extract from frequency measurement parameters such as the exact time that indicates the start of the downward or upward trend caused by a power imbalance event in the power grid. Typical frequency patterns of system disturbance events are analyzed for actual power system.

Monitoring the North American interconnections at distribution level

The North American Frequency Monitoring Network (FNET) is a wide-area measurement system that monitors the North American Interconnections at distribution voltage level. A situational awareness system has been implemented on the server located at Virginia Tech to detect and analyze power system disturbances in near-real time. This paper demonstrates the viability of monitoring bulk transmission systems at a very low voltage level by discussing several major disturbances in the Eastern Interconnection (EI) observed by FNET. Important parameters of power systems, such as frequency, voltage and phase angle, are examined to understand system behavior during disturbances. The recordings and analysis show that a great deal of valuable information about dynamics in transmission systems can be obtained at a lower voltage level. The disturbance location estimation is also analyzed as an application of the distribution-level measurements.