Kenneth M. Hopkinson

EPOCHS: a platform for agent-based electric power and communication simulation built from commercial off-the-shelf components

This paper reports on the development and subsequent use of the electric power and communication synchronizing simulator (EPOCHS), a distributed simulation environment. Existing electric power simulation tools accurately model power systems of the past, which were controlled as large regional power pools without significant communication elements. However, as power systems increasingly turn to protection and control systems that make use of computer networks, these simulators are less and less capable of predicting the likely behavior of the resulting power grids. Similarly, the tools used to evaluate new communication protocols and systems have been developed without attention to the roles they might play in power scenarios. EPOCHS integrates multiple research and commercial off-the-shelf systems to bridge the gap.

A Trust System Architecture for SCADA Network Security

This paper discusses the use of a communications network security device, called a trust system, to enhance supervisory control and data-acquisition (SCADA) security. The major goal of the trust system is to increase security with minimal impact on existing utility communication systems. A previous paper focused on the technical operation of the trust system by augmenting routers to protect User Datagram Protocol (UDP)-based traffic. This paper concentrates on placing the trust system into a broader context, creates new trust system implementations to increase its flexibility, and demonstrates the trust system using TCP traffic. Specifically, the article expands on previous work in the following ways: 1) the article summarizes major threats against SCADA systems; 2) it discusses new trust system implementations, which allow the trust system to be used with a wider array of network-enabled equipment; 3) it discusses key SCADA security issues in the literature and shows how the trust system responds to such issues; 4) the paper shows the impact of the trust system when widely prevalent TCP/IP network communication is used; and 5) finally, the paper discusses a new hypothetical scenario to illustrate the protection that a trust system provides against insider threats.

Agent technology applied to adaptive relay setting for multi-terminal lines

This paper discusses the adaptation of the settings of distance relays for multi-terminal lines employing agents. Agents are software processes capable of searching for information in networks, interacting with pieces of equipment and performing tasks on behalf of their owners (relays). Results illustrating the performance of the adaptive method proposed compared to conventional fixed settings are presented. It is shown that the digital relays and agents acting within a communication structure (also called middleware) can alter adaptive settings to ensure correct performance over a wide variety of operation conditions, without the need of an additional communication link. The proposed relaying scheme can also be utilized for first zone clearing over the entire line.

Using a Distributed Agent-Based Communication Enabled Special Protection System to Enhance Smart Grid Security

Future smart grid capabilities promise to leverage network technologies to revolutionize the production, transmission, distribution, and consumption of electrical power. This smart grid revolution is more than just smart meters. Improvements in situational awareness are also likely to enhance security and reliability in power transmission systems. However, reliance on Internet-like communication networks also exposes vulnerabilities to increased risk from cyber-attack and other forms of Byzantine (i.e., anomalous) behavior. This article advocates the use of an agent-based decentralized protection system using peer-to-peer communications, reputation-based trust and a data retransmission scheme to combat malicious attacks and other Byzantine failures. The research presented used the electric power and communication synchronizing simulator (EPOCHS) federated simulation platform to demonstrate the added robustness provided to a special protection system in the face of an adversary by successfully defending against malicious attacks. Simulation results show promise for this approach.

Quality-of-Service Considerations in Utility Communication Networks

This paper discusses the impact that communication will have on the electric power grid in the future. Recent efforts, such as UCA 2.0 and IEC 61850, are establishing a standard way for electric power substations, intelligent electronic devices, and other apparatus to communicate over data networks. These efforts pave the way to a future where protection and control of the electric power grid will migrate towards a common utility intranet. The intranet will almost certainly be based on Internet standards due to their widespread use, low cost, and easy migration path over time. A utility intranet, common to the utilities but separate from the Internet, will allow for the eventual connection of regional substations, equipment, and control centers throughout the grid. The transition will allow capabilities beyond what is currently available, but it requires a careful understanding of the implications for network capacity constraints, protocol selections, and quality-of-service technologies. This paper discusses the benefits of utility communication, the likely pitfalls in the use of Internet technology for protection and control systems, and technologies that can help to mitigate those pitfalls. This paper also introduces a model for the expected background traffic that will be present in a utility intranet. Experimental results illustrate the use of different communications protocols in representative power situations in the face of different levels of background traffic in the electric power and communication synchronizing simulator simulation environment.

An Agent-Based Current Differential Relay for Use with a Utility Intranet

This paper proposes an agent-based current differential relay for use with a communication network. Agents are software processes capable of searching for information in networks, interacting with pieces of equipment, and performing tasks on behalf of their owners (relays). Results illustrating the performance of the agent-based differential method proposed acting within a communication structure are presented for different traffic conditions. These results also show that a dedicated utility Intranet is a viable and recommended option as a communication media for the proposed scheme.

Distributed Fault-Tolerant Quality of Wireless Networks

A mobile ad hoc network (MANET) consists of a group of communicating hosts that form an arbitrary network topology by means of any of several wireless communication media. MANET communications represent a diversification in communication technology necessary to solve the stringent end-to-end requirements of QoS-based communication networks. Of the many challenges in this complex distributed system, the problem of routing based on a predefined set of customer preferences, critical to guaranteeing quality-of-service, is the focus of this research. Specifically, this paper modifies a cluster-based QoS routing algorithm for mobile ad hoc networks with the aim of providing fault tolerance, which is a critical feature in providing QoS in the link failure-prone environment of mobile networks. Performance of this new fault-tolerant cluster-based QoS wireless algorithm is evaluated according to failure recovery time, dropped packets, throughput, and sustained flow bandwidth via simulations involving node failure scenarios along QoS paths.

The Modeling and Verification of Peer-to-Peer Negotiating Multiagent Colored Petri Nets for Wide-Area Backup Protection

This paper focuses on the modeling and verification of a peer-to-peer wide-area backup protection (WABP) system. Agents located in a number of substation intelligent electronic devices (IEDs) negotiate on a peer, or equal, basis. The agent-based wide-area backup protection scheme is able to find power-line faults and protection misoperations. A wide-area communication network based on IP technology is used to transmit shared information among the agents. A novel agent-oriented peer-to-peer negotiating colored Petri net (AOPCPN) is proposed to implement the WABP system. The algorithms, design, and dynamic behavior of the WABP is evaluated in a simulated environment to demonstrate its benefits. The article begins by presenting the generic AOPCPN architecture and its formal definition. The AOPCPN model for the WABP multiagent system is evaluated according to one algorithm, which is detailed in this article. The WABP agents autonomy, cooperation, parallel operation, and robustness are embodied in modules in order to ease the software engineering challenges in implementing and maintaining the agents. Three example scenarios illustrate the effectiveness of the Petri net model and its ability to dynamically respond to WABP misoperations and fault conditions.

Reputation-Based Trust for a Cooperative Agent-Based Backup Protection Scheme

This paper explores integrating a reputation-based trust mechanism with an agent-based backup protection system to help protect against malicious or byzantine failures. A distributed cooperative trust system has the potential to add an additional layer of protection designed to operate with greater autonomy. This trust component enables the agents in the system to make assessments using an estimate of the trustworthiness of cooperating protection agents based on their responsiveness and the consistency of their responses when compared with their peers. Results illustrate the improved decision-making capability of agents who incorporate this cooperative trust method in the presence of failures in neighboring relays.

Trust Management and Security in the Future Communication-Based "Smart" Electric Power Grid

New standards and initiatives in the U.S. electric power grid are moving in the direction of a smarter grid. Media attention has focused prominently on smart meters in distribution systems, but big changes are also occurring in the domains of protection, control, and Supervisory Control and Data Acquisition (SCADA) systems. These changes promise to enhance the reliability of the electric power grid and to allow it to safely operate closer to its limits, but there is also a real danger concerning the introduction of network communication vulnerabilities to so-called cyber attacks. This article advocates the use of a reputation-based trust management system as one method to mitigate such attacks. A simulated demonstration of the potential for such systems is illustrated in the domain of backup protection systems. The simulation results show the promise of this proposed technique.