In this tutorial we present the state-of-the-art as well as new methods for simulating various planning, operation, stability, reliability, and economic models of electric power systems. The discussion is driven by both first-principle models and empirical models. First-principle models result from the fundamental physics and engineering principles that govern the behavior of various components of a grid. Empirical models, on the other hand, are models that result from statistics and data analysis. We overview a wide spectrum of applications starting from planning models with a time-scale of simulation in years to real-time models where the time-scale can be in the order of milliseconds. We present a list of simulation software popularly used by the power engineering research community across the world. The increasingly important roles of power electronics, communication and computing, model aggregation, hybrid simulation, faster-than-real-time simulation, and co-simulation in emulating the daily operation of a grid are enumerated. The importance of research testbeds for testing, verification and validation of complex grid models at various temporal and spatial scales is also highlighted. The overall goal is to provide a vision on how simulations and their supporting implementation methods can help us in understanding the evolving behavior of tomorrow's power networks as a truly intelligent cyber-physical system.

Both the communication limitation and the measurement properties based algorithm become the bottleneck of enhancing the traditional power system state estimation speed. The availability of synchro-phasor data has raised the possibility of a linear state estimator if the inputs are only complex currents and voltages and if there are enough such measurements to meet observability and redundancy requirements. The fiber optics communication network and advanced distributed computing and database technology provide the platform for fast state estimator. Moreover, the new digital substations can perform some of the computation at the substation itself resulting in a more accurate two-level state estimator. The main contribution of this paper is to propose a two-level fast linear state estimator based on the synchronized phasor measurements infrastructures. We described the layered architecture of databases, communications, and the application programs that are required to support this two-level linear state estimator and the mathematical algorithms that are different from those in the existing literature. This paper also describes potential benefits of applying fast state estimator and how it can provides a pathway to the smart transmission grid of the future.

In recent years, much of the discussion involving “smart grids” has implicitly involved only the distribution side, notably advanced metering. However, today's electric systems have many challenges that also involve the rest of the system. An enabling technology for improving the power system, which has emerged in recent years, is the ability to measure coherent, real-time data. In this paper, we describe major challenges facing electrical generation and transmission today that availability of these measurements can help address. We overview applications using coherent, real-time measurements that are in use today or proposed by researchers. Specifically, we describe, normalize, and then quantitatively compare key factors for these power applications that influence how the delivery system should be planned, implemented, and managed. These factors include whether a person or computer is in the loop and (for both inputs and outputs) latency, rate, criticality, quantity, and geographic scope. From this, we abstract the baseline communications requirements of a data delivery system supporting these applications and suggest implementation guidelines to achieve them. Finally, we overview the state of the art in the supporting computer science areas of overlay networking and distributed computing (including middleware) and analyze gaps in commercial middleware products, utility standards, and issues that limit low-level network protocols from meeting these requirements when used in isolation.

Functional verification is a major part of the effort to design electronic systems. Over the years, EDA has developed a suite of tools and methods to address the verification challenges by a patchwork of approaches. However, as the system complexity continues to increase, traditional methods may not be adequate to ensure flawless behavior. In this educational panel, we will explore how complex systems are validated in other areas. Four speakers will cover the verification challenges in airplane design, complex Mars exploration missions, modeling and rendering of movie animations, and the design of continent-wide national power grids. Using real-life examples, each speaker will introduce the general topic, outline the specific verification challenges, and discuss how they are approached in their specific domain. The following discussion will analyze commonalities and differences between the areas and explore lessons to be learned from them for EDA.

The power grid is not only a network interconnecting generators and loads through a transmission and distribution system, but is overlaid with a communication and control system that enables economic and secure operation. This multilayered infrastructure has evolved over many decades utilizing new technologies as they have appeared. This evolution has been slow and incremental, as the operation of the power system consisting of vertically integrated utilities has, until recently, changed very little. The monitoring of the grid is still done by a hierarchical design with polling for data at scanning rates in seconds that reflects the conceptual design of the 1960s. This design was adequate for vertically integrated utilities with limited feedback and wide-area controls; however, the thesis of this paper is that the changing environment, in both policy and technology, requires a new look at the operation of the power grid and a complete redesign of the control, communication and computation infrastructure. We provide several example novel control and communication regimes for such a new infrastructure.

In this paper, we review the functions and architectures of control centers: their past, present, and likely future. The evolving changes in power system operational needs require a distributed control center that is decentralized, integrated, flexible, and open. Present-day control centers are moving in that direction with varying degrees of success. The technologies employed in today's control centers to enable them to be distributed are briefly reviewed. With the rise of the Internet age, the trend in information and communication technologies is moving toward Grid computing and Web services, or Grid services. A Grid service-based future control center is stipulated.

A broad overview of on-line power system security analysis is provided, with the intent of identifying areas needing additional research and development. Current approaches to state estimation are reviewed and areas needing improvement, such as external system modeling, are discussed. On-line contingency selection has become practical, particularly for static security. Additional work is necessary to identify better indices of power system stress to be used in on-line screening filters for both static and dynamic security analysis. Use of optimal power flow schemes to recommend optimal preventive and corrective strategies is presented on a conceptual level. Techniques must be further developed to provide more practical contingency action plans, which include real-world operating considerations and use a reasonably small number of control actions. Techniques must be developed for costing operating variables which are not easily quantified in dollars. Soft or flexible constraints and time variables must be included in the preventive and corrective strategy formulation. Finally, the area of on-line transient and dynamic security analysis is presented.>

The use of large digital computers in control centers has made it possible to track the changing conditions in the power system with a mathematical model in the computer. This real-time model can be used to assess the security of the present system as well as to check out possible control strategies. In this paper the various steps in constructing the model from the real-time measurements are described. These steps include the determination of the network topology, the estimation of the network state, and the approximate modeling of the unobservable (external) network. This paper also discusses the checks for observability and bad measurements, and the calculation of bus load forecast factors and generator penalty factors.