Showing papers by "Chen-Ching Liu published in 2005"

Strategic Power Infrastructure Defense

Abstract: This paper provides a comprehensive state-of-the-art overview on power infrastructure defense systems. A review of the literature on the subjects of critical infrastructures, threats to the power grids, defense system concepts, and the special protection systems is reported. The proposed Strategic Power Infrastructure Defense (SPID) system methodology is a real-time, wide-area, adaptive protection and control system involving the power, communication, and computer infrastructures. The SPID system performs the failure analysis, vulnerability assessment, and adaptive control actions to avoid catastrophic power outages. This paper also includes a new concept for bargaining by multiagents to identify the decision options to reduce the system vulnerability. The concept of a flexible configuration of the wide-area grid is substantiated with an area-partitioning algorithm. A 179-bus system is used to illustrate the area partitioning method that is intended to minimize the total amount of load shedding.

State-of-the-art of electricity price forecasting

Abstract: Since the deregulation of the electricity power industry, many methods and techniques have been developed to forecast the electricity prices in the competitive environment. This paper classifies and compares different techniques in the literature of electricity price forecasting. The information is summarized based on the technical objectives, scope, time horizon, input data and the level of accuracy. The methods and techniques for electricity price forecasting are categorized into equilibrium analysis, simulation methods, time series, econometric methods, intelligent systems, and volatility analysis

Implementation of reliability-centered maintenance for circuit breakers

Abstract: Power system reliability is highly related to the way maintenance tasks on system equipment are performed. Time-based maintenance (TBM) has been practiced as the usual maintenance scheduling strategy in electrical energy systems for many years. While this approach has the advantage of simple scheduling and high availability, it is not the most cost effective. The objective of this project is to develop a generic decision support tool for maintenance of power circuit breakers based on the concept of reliability-centered maintenance (RCM). Reliability-centered maintenance not only considers the actual condition of a piece of equipment but also the relative importance of the equipment to the whole system and is expected to be more cost effective than the traditional approaches.

Adaptation of relay operations in real-time

Abstract: Relays can degrade power system performance if they fail or are set incorrectly. Reports have shown that this degradation can lead to cascading outages. This paper will show how real-time communication with relays can help prevent these consequences. Through laboratory simulations, it is shown that real-time communication to protective relays can be achieved. This paper reports a new system that adapts automatic relay responses to make the power system more secure. The method of operation is explained.

Topology error identification for the NEPTUNE power system

Abstract: The goal of the North Eastern Pacific Time-Series Undersea Networked Experiment (NEPTUNE) is to provide the infrastructure necessary for scientific exploration and investigation on the floor of the Pacific Ocean in an area encompassing the Juan de Fuca Tectonic Plate. In order to achieve this goal, the power delivery capabilities of the terrestrial distribution system will be extended into the Pacific Ocean. The power system associated with the proposed observatory is unlike conventional terrestrial power systems due to the unique under ocean operating conditions. The operating requirements of the system dictate hardware and software applications that are not found in terrestrial power systems. This paper describes a method for topology error identification in the presence of various forms of measurement errors for NEPTUNE, a highly interconnected DC power system. Hardware and reliability requirements have led to a power system configuration that includes a large number of unmeasured sections. Using previously developed state estimation algorithms as a starting point, a methodology for system topology identification is proposed in this paper.

Energy-based stability margin computation incorporating effects of ULTCs

Abstract: This paper introduces a new definition and computation method for the energy margin as a means to quantify the degree of stability of a dynamic power system model. The method is based on detailed device modeling that spans both transient and midterm time scales and includes effects of under-load tap-changer (ULTC) actions. The energy margin is defined as the minimum distance in potential energy space between the first- and second-kick trajectories, where the latter is chosen to be marginally stable. A generalized second-kick design is proposed. This consists of a combination of a load-step first kick and a three-phase fault second kick, applied at a time instant when the system is "closest" to the boundary of the stability region. The value of the energy margin is tracked through various tap-changer configurations. Thus, situations where ULTC actions are detrimental to stability can be uncovered, and "optimal" tap positions can be found. The concept is first illustrated on a single-machine infinite bus (SMIB); then, results are shown for a ten-bus voltage stability test system and for a modified version of the standard IEEJ 60-Hz test system, where some loads are fed through step-down ULTCs.

An Intelligent System For Price Forecasting Accuracy Assessment

Abstract: For a market player, in order to perform an optimal risk management, it is important to have not only suitable price forecasting tools taking into account the most significant price drivers but also methods to quantify their accuracy. This paper proposes an intelligent system for price forecasting accuracy assessment (ISPF). The core of ISPF is a fuzzy interpolator of the effects of the price drivers; the output is a set of pre-defined price indices over a medium term period. The computational efficiency of ISPF allows its repeated application in a Monte Carlo methodology, in order to calculate the price indices corresponding to a very large number of price drivers values combinations and, then, to determine the probability distributions of the corresponding price indices. The paper reports an application of the proposed ISPF to the forecasted Italian market scenario for year 2005

Topology Error Identification for the

Abstract: The goal of the North Eastern Pacific Time-Series Un- dersea Networked Experiment (NEPTUNE) is to provide the infra- structure necessary for scientific exploration and investigation on the floor of the Pacific Ocean in an area encompassing the Juan de Fuca Tectonic Plate. In order to achieve this goal, the power delivery capabilities of the terrestrial distribution system will be extended into the Pacific Ocean. The power system associated with the proposed observatory is unlike conventional terrestrial power systems due to the unique under ocean operating conditions. The operating requirements of the system dictate hardware and soft- ware applications that are not found in terrestrial power systems. This paper describes a method for topology error identification in the presence of various forms of measurement errors for NEP- TUNE, a highly interconnected DC power system. Hardware and reliability requirements have led to a power system configuration that includes a large number of unmeasured sections. Using previ- ously developed state estimation algorithms as a starting point, a methodology for system topology identification is proposed in this paper.

Closure to discussion on "Web-based tutoring in power engineering"

Abstract: For original article by H. Li, C.-C. Liu and M. J. Damborg see ibid., vol.18, no.4, p.1227-34, Nov. 2003 and for discussion by N. P. Pradhy see ibid., vol.20, no.2, p.1193, May 2005.