David E. Whitehead

Smart Generation and Transmission With Coherent, Real-Time Data

In recent years, much of the discussion involving “smart grids” has implicitly involved only the distribution side, notably advanced metering. However, todays 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.

Synchrophasor-based power system protection and control applications

Synchrophasor data consist of analog and digital values with an associated precise time stamp. With precise time, these quantities are collected from various locations, time-aligned, and then processed as a coherent data set. Synchrophasors have generally been used for visualization and post-event analysis. However, new technologies allow synchrophasors to be processed in real time. Synchrophasor systems are now being used for realtime wide-area protection and control. This paper examines several ways synchrophasors are being used: · Voltage stability detection and correction · Load/generator shedding · Islanding control · Intermittent generation source control and grid interconnection Each application includes a discussion of how synchrophasors provided a unique solution and benefit over traditional solutions. Application performance, speed, data requirements, and equipment are also reviewed. We also discuss a future time-synchronized control solution.

Real-Time Power System Control Using Synchrophasors

To date, synchronized phasor measurements have been used mainly for power system model validation, postevent analysis, real-time display, and other similar activities. However, synchrophasors have a greater potential than monitoring and visualization. Synchrophasors will increasingly contribute to the reliable and economical operation of power systems as real-time control and protection schemes become broadly used. Synchronous phasor measurements are now available in relays and meters; however, a practical means of processing the data in real time had been lacking. This paper describes a synchronous vector processor and several practical applications, including automated diagnostics, remedial action schemes, direct state measurement, and stability assessment.

Real-world synchrophasor solutions

Synchrophasors are no longer an academic curiosity. Today synchrophasors are providing solutions that otherwise would have been too expensive or too complicated to implement with traditional approaches. This paper examines ten synchrophasor applications being applied to monitor, visualize, and control electric power systems. 1. Voltage and current phasing verification 2. Substation voltage measurement refinement 3. SCADA verification and backup 4. Communications channel analysis 5. Wide-area frequency monitoring 6. Improved state estimation 7. Wide-area disturbance recording 8. Distributed generation control 9. Synchrophasor-assisted black start 10. Synchrophasor-based protection Included with each application is a description of the required equipment, communications channels, and data rates.

Line protection: Redundancy, reliability, and affordability

In this paper, we apply fault tree analysis to compare the dependability and security of line protection schemes with different degrees of redundancy. We also compare the scheme costs. For each scheme, we use a basic protection scheme as the reference. We then evaluate schemes with double redundancy and two-out-of-three voting schemes. We also evaluate the effect of comprehensive commissioning testing, hidden failures, and common-mode failures, as well as using relays from the same or different manufacturers in redundant schemes.

How would we know

Modern power system monitoring, protection, automation, and control rely on communications and computing technology. Along with the benefits of these technologies come some risks of electronic or cyber attack. There are legitimate concerns about how inadequate information security (cyber security) is affecting electric power systems and other critical infrastructure. As a result of cyber security threats, both governments and industry are putting forth significant effort to improve critical infrastructure security. In the United States, for example, electric power utilities must now follow a set of cyber security standards. Security practices are evolving and improving, and new products and architectures are being developed and applied to counter the ever-increasing sophistication of attacker exploits that attempt to access, inspect, manipulate, and control critical infrastructure control systems. A fundamental question is “How would we know if our assets are being explored and exploited?” An attack strategy would likely include a number of initial probes, data collection, tests, and other activities as the adversary develops intelligence and capabilities against a target. To counter this strategy, asset owners need to detect the activities of the intruder. In part, this paper takes the perspective of an engineer investigating a FICTITIOUS incident, using the records and “fingerprints” an attacker would likely leave behind, which we can use to identify when our systems have been compromised. The paper explains how to answer the question using the many tools readily available in devices and systems in service today. These tools include access logs and syslogs, event reports, sequential events reports, information at adjacent stations, alarms, and precision timing. We also investigate some system design choices that make the process of answering the question easier. Finally, we make some recommendations that not only help answer the question “How would we know?” but also make an adversarys job much more difficult.

Advanced commercial power system protection practices applied to naval medium voltage power systems

In the U.S. navys transition to an all-electric ship, system designers must take great care to ensure that critical design choices provide highly reliable and safe power system operation and protection during all mission scenarios. Transitioning from low voltage (450 V/sub AC/) radial configurations to medium voltage (13.8 kV/sub AC/) multi-source systems requires new naval protection schemes. This paper specifically analyzes methods for quickly determining ground faults in ungrounded and high-impedance grounded naval power systems.

Practical synchronized phasor solutions

Time-synchronized phasors provide solutions for power system analysis and control. This paper shares practical applications, using real-world implementations. Example systems include phase verification, measurement refinement, SCADA verification, communications channel analysis, frequency monitoring, improved state estimation, disturbance recording, black-start control, and protection.

Ukraine cyber-induced power outage: Analysis and practical mitigation strategies

On December 23, 2015, a “temporary malfunction of the power supply” in three provinces in Ukraine resulted in power outages that lasted up to six hours and affected 225,000 customers. Following the event, an investigation identified evidence that several regional Ukraine power control systems had been compromised by cyber attacks. This was the first publicly documented successful cyber attack on an electric utilitys control system. Both asset owners and government officials around the world now are asking, “What happened and could a similar cyber attack happen in our control systems?” This paper provides an analysis of the Ukraine cyber attack, including how the malicious actors gained access to the control system, what methods the malicious actors used to explore and map the control system, a detailed description of the December 23, 2015 attacks, and methods used by the malicious actors to erase their activities and make remediation more difficult. We then present a detailed description of securing utility power system control systems based on best practices, including control system network design, whitelisting techniques, monitoring and logging, and personnel education. The paper concludes with a discussion of mitigation methods and recommendations that would have protected the Ukraine control system and alerted personnel in advance of the cyber attack.

Millisecond, microsecond, nanosecond: What can we do with more precise time?

Our industry moves energy at the speed of light, at the flick of a switch. A transmission line transporting 1500 megawatts delivers the equivalent of 250 pounds of coal per second, already converted into a convenient form of energy. For decades, we considered time in seconds or cycles: such as fuse curves and breaker clearing times. About three decades ago, our thinking moved into milliseconds because we needed to get better at quickly understanding wide-area events, protection was getting faster allowing for more power transfer, and the technology made it possible. Over the past decade, we have come to appreciate how synchrophasors can help us understand, control, and protect our power systems. One electrical degree at 60 hertz is about 46 microseconds, so measurements accurate to ten microseconds give us accurate synchrophasors. Traveling-wave technologies can put nanosecond resolution to good use. Achieving nanosecond absolute time is practical, affordable, and useful. In this paper, we explore how more-accurate time can improve the performance of electric power systems.