Optimization and Security Challenges in Smart Power Grids

At the heart of the future smart grid lie two related challenging optimization problems: unit commitment and economic dispatch. The contemporary practices such as intermittent renewable power, distributed generation, demand response, etc., induce uncertainty into the daily operation of an electric power system, and exacerbate the ability to handle the already complicated intermingled problems. We introduce the mathematical formulations for the two problems, present the current practice, and survey solution methods for solving these problems. We also discuss a number of important avenues of research that will receive noteworthy attention in the coming decade.

Electric power grids in this country and abroad are undergoing revolutionary changes through the increased integration of electric power generation, delivery and consumption with computation, communications, and cyber security. Emerging out of these activities is a smart grid that includes new technologies ranging from microgrids capable of islanded operation to wind power generation and electric vehicle supply. The success of this massive endeavor will depend on large measure on the development of control methodologies that maintain homeostasis in the face of natural stresses, malfunctions and deliberate attacks. The goal of this chapter is to sketch out possible control strategies for the future smart grid based upon insights into how living systems deal with these same issues. This is a broad topic and the particular focus here will be on presenting a simple model of control by neural and innate immune systems that could be applied to operational security at substations and microgrids.

The distribution system sectionalization (recloser placement) and reconfiguration (closed/open status of reclosers) are receiving increasing interest in the field of feeder design and operation. They are becoming an intrinsic feature of the emerging smart grids by contributing to their reliability and self-healing capability. The majority of sectionalization methods are combinatorial suggesting the development of multiple sectionalization scenarios, and iterative. The goal of the chapter is to present a novel sectionalization method giving an optimal recloser placement scenario at one straightforward calculation. The sectionalization rationale is to split a radial grid into sections with equal portions of operator’s interruption cost in the initial configuration, where the interruption cost consists of non-distributed energy cost and fault clearing cost. The optimization is referred to as minimization of non-distributed energy cost for 3-overhead-feeder distribution grid with 3 independent supply points. It provides both single and double sectionalization, with one and two reclosers per feeder, respectively. The method also suggests the evaluation of investment efficiency of the sectionalization in the considered period. It was validated as an effective procedure for the 10-kV test grid in numerical setup with 43 nodes, corresponding to the Lithuanian critical line data. The method-based sectionalization was compared with the reason-based one in order to quantify the optimisation effect.

The demand side of the electricity system holds a flexibility resource which has been ignored for a long time. With the presence of smart grids and facing challenges such as the massive integration of renewable energies into the system, demand side measures become viable and indispensable. This chapter will give a brief introduction about the concept of demand response. It will give an overview on demand response mechanisms, their objectives and potentials. Furthermore, an overview about various flexible demands in households, commerce and industries is given.

The functionalities of a Smart Grid include the use of a network of power management devices to control the demand-based power distributions, dynamic pricing, reliable power quality monitoring, self-healing, and other customer services within the grid. However, by the very nature of these functions, there arises a great need for system security as the network connection offers would-be hostile attackers an ideal target. A protection mechanism that is adaptive and forward looking for the types of attacks that are unaccounted in terms of the latent system vulnerabilities is explored in this chapter. The method of learning normal operations and monitoring for abnormal operations has the potential for providing increased security and tamper detection within the grid. This chapter reviews present day state-of-the-art behavior monitoring and anomaly detection methods along with a presentation of a new method for learning event patterns and detecting anomalies for the purposes of tamper detection.

The Smart Grid will enhance the generation, distribution, transmission, and use of electricity by incorporating elements that will greatly help improve energy efficiency. In addition to traditional components, it will also incorporate small-scale generators, such as home wind turbines and solar panels, into the larger grid. In order to enable energy efficiency as well as other features, two-way communication between utilities and customers (users) will be required. This communication will most likely travel in large part over public networks. The Smart Grid, through the addition of bi-directional communication links throughout the infrastructure, will enable utilities to enhance their service, monitoring, and maintenance activities. Electric power substations will play a major role in the Smart Grid. IEC 61850 is a family of standards that defines network protocols, and data and device naming conventions for electric substation automation. IEC 61850 provides utilities with the ability to better monitor operation and even remotely control the substation when necessary. Part of the utility-substation communication link will be facilitated by public networks (e.g. the Internet). This chapter provides an overview of the IEC 61850 standards and discusses recent experiences with IEC 61850. Challenges facing IEC 61850 deployments, namely security, are presented. Potential solution paths to these challenges are provided.

Future bulk electric transmission systems will include substation automation, synchrophasor measurement systems, and automated control algorithms which leverage wide area monitoring systems to better control the grid. Prior to installation of new networked devices, utilities should perform cybersecurity testing and develop corrective actions for identified vulnerabilities. This chapter discusses a set of cyber security requirements developed for phasor measurement units and phasor data concentrators, two intelligent electronic devices which will be added to utility networks to implement synchrophasor systems. Five classes of cyber security requirements are presented; compliance, access, availability, integrity, and confidentiality. Next this chapter discusses testing multiple phasor measurement units and phasor data concentrators from multiple vendors. The test section provides guidance on testing for each requirement and discusses generalized test results.

The deployment of smart grid technologies is drawing significant attention in the electric power industry. The term “smart grid” refers to modernization of the electric grid using digital technology that includes an advanced sensing and metering infrastructure, high speed, fully integrated two-way communications, and a supporting information infrastructure. In particular, the smart grid combines matured electric grid infrastructure with information and communication technology to offer better grid performance in terms of overall system efficiency and reliability. It supports a two-way energy and information flow, facilitates the integration of time-varying energy sources and new dynamic loads, and amongst other things. However, along with these potential benefits, smart grid also brings new challenges in ensuring security of the grid and the information infrastructure that connects and controls it. This chapter presents a brief survey of various essential components of smart grid and some of the security challenges that encompass virtually all aspects of its operation.

The manipulation of critical physical processes and the falsification of system state is a relevant concern for many modern control systems. Common approaches to this problem such as network traffic and host based state information analysis feature difficulties such as high false alarm rate. Furthermore, issues in integrating the system state falsification detection into an existing control system such as cost or technical issues, impose additional difficulties. To alleviate these issues, a low cost and low false alarm rate method for improved cyber-state awareness of critical control systems, the Known Secure Sensor Measurements (KSSM) method, was proposed by the authors of this chapter. This chapter reviews the previously developed theoretical KSSM concept and then describes a simulation of the KSSM system. The presented KSSM method constitutes a reliable mechanism for detecting manipulation of critical physical processes and falsification of system state. Unlike other network based approaches, the method utilizes the physical measurements of the process being controlled to detect falsification of state. In addition, the KSSM method can be incrementally integrated with existing control systems for critical infrastructures. To demonstrate the performance and effectiveness in detecting various intrusion scenarios, a simulated experimental control system network was combined with the KSSM components. The KSSM method is intended to be incorporated into the design of new, resilient, cost effective critical infrastructure control systems.

Data diodes provide protection of critical cyber assets by the means of physically enforcing traffic direction on the network. In order to deploy data diodes effectively, it is imperative to understand the protection they provide, the protection they do not provide, their limitations, and their place in the larger security infrastructure. In this work, we study data diodes, their functionalities and limitations. We then propose two critical infrastructure systems that can benefit from the additional protection offered by data diodes: process control networks and net-centric cyber decision support systems. We review the security requirements of these systems, describe the architectures, and study the trade-offs. Finally, the architectures are evaluated against different attack patterns.