Survey on synchrophasor data quality and cybersecurity challenges, and evaluation of their interdependencies

Synchrophasor devices guarantee situation awareness for real-time monitoring and operational visibility of smart grid. With their widespread implementation, significant challenges have emerged, especially in communication, data quality and cybersecurity. The existing literature treats these challenges as separate problems, when in reality, they have a complex interplay. This paper conducts a comprehensive review of quality and cybersecurity challenges for synchrophasors, and identifies the interdependencies between them. It also summarizes different methods used to evaluate the dependency and surveys how quality checking methods can be used to detect potential cyberattacks. This paper serves as a starting point for researchers entering the fields of synchrophasor data analytics and security

Design and implementation of a low-cost phasor measurement unit: a comprehensive review

The complexity of the contemporary electrical power systems imposes challenges in aspect of monitoring, protection and control. In order to obtain high speed of response, wide area effect and prices synchronization, the grid control functions can be benefited by the implementation of Phasor Measurement Units (PMU). The paper is aimed to make a review of the commercial implementation of Phasor Measurement Units and then open source based implementations (open architecture hardware and software). This paper focuses on standard implementations; as a consequence the concept of virtual PMU is not discussed here

TESTING OF RECURSIVE AND NON-RECURSIVE ALGORITHMS FOR REAL-TIME PHASOR AND FREQUENCY ESTIMATIONS IN POWER SYSTEMS

Steady-state performance of various recursive and non-recursive algorithms are tested in this report according to the test signals given in the IEEE Standard C37.118.1-2011. Phase magnitude and phase angle of the power grid signals have been estimated using Discrete Fourier Transform (non-recursive), Discrete Fourier Transform (recursive), Least Square, and Wavelet Transform Algorithms. Frequency estimation is performed using Discrete Fourier Transform, Weighted Least Square, and Zero Crossing methods. These algorithms are evaluated in LabView software and tested by generating test signals in a Simulink model. Furthermore, Total Vector Error (TVE) is calculated using dynamic test signals as per the IEEE Standard C37.118-2011. Performance of different algorithms are analyzed for various cases and the value of TVE is compared with the permissible error limits given in the standard

Scenarios for the development of smart grids in the UK: literature review

Smart grids are expected to play a central role in any transition to a low-carbon energy future, and much research is currently underway on practically every area of smart grids. However, it is evident that even basic aspects such as theoretical and operational definitions, are yet to be agreed upon and be clearly defined. Some aspects (efficient management of supply, including intermittent supply, two-way communication between the producer and user of electricity, use of IT technology to respond to and manage demand, and ensuring safe and secure electricity distribution) are more commonly accepted than others (such as smart meters) in defining what comprises a smart grid. It is clear that smart grid developments enjoy political and financial support both at UK and EU levels, and from the majority of related industries. The reasons for this vary and include the hope that smart grids will facilitate the achievement of carbon reduction targets, create new employment opportunities, and reduce costs relevant to energy generation (fewer power stations) and distribution (fewer losses and better stability). However, smart grid development depends on additional factors, beyond the energy industry. These relate to issues of public acceptability of relevant technologies and associated risks (e.g. data safety, privacy, cyber security), pricing, competition, and regulation; implying the involvement of a wide range of players such as the industry, regulators and consumers. The above constitute a complex set of variables and actors, and interactions between them. In order to best explore ways of possible deployment of smart grids, the use of scenarios is most adequate, as they can incorporate several parameters and variables into a coherent storyline. Scenarios have been previously used in the context of smart grids, but have traditionally focused on factors such as economic growth or policy evolution. Important additional socio-technical aspects of smart grids emerge from the literature review in this report and therefore need to be incorporated in our scenarios. These can be grouped into four (interlinked) main categories: supply side aspects, demand side aspects, policy and regulation, and technical aspects.

Vulnerability analysis of satellite-based synchronized smart grids monitoring systems

The large-scale deployment of wide-area monitoring systems could play a strategic role in supporting the evolution of traditional power systems toward smarter and self-healing grids. The correct operation of these synchronized monitoring systems requires a common and accurate timing reference usually provided by a satellite-based global positioning system. Although these satellites signals provide timing accuracy that easily exceeds the needs of the power industry, they are extremely vulnerable to radio frequency interference. Consequently, a comprehensive analysis aimed at identifying their potential vulnerabilities is of paramount importance for correct and safe wide-area monitoring system operation. Armed with such a vision, this article presents and discusses the results of an experimental analysis aimed at characterizing the vulnerability of global positioning system based wide-area monitoring systems to external interferences. The article outlines the potential strategies that could be adopted to protect global positioning system receivers from external cyber-attacks and proposes decentralized defense strategies based on self-organizing sensor networks aimed at assuring correct time synchronization in the presence of external attacks

Novel performance evaluation of information and communication technologies to enable wide area monitoring systems for enhanced transmission network operation

This thesis was submitted for the award of Doctor of Philosophy and was awarded by Brunel University London.The penetration of renewable energy sources has increased significantly in recent years due to the ongoing depletion of conventional resources and the transition to a low carbon energy system. Renewable energy sources such as wind energy are highly intermittent and unpredictable in nature, which makes the operation of the power grid more dynamic and therefore more complex. In order to operate the power system reliably under such conditions, Phasor Measurement Units (PMUs) through the use of satellite technology can offer a state-of-the-art Wide Area Monitoring System (WAMS) for improving power system monitoring, control and protection. They can improve the operation by providing highly precise and synchronised measurements near to real-time with higher frequency and accuracy. In order to achieve such objectives, a high-speed and reliable communications infrastructure is required to transfer time-critical PMU data from remote locations to the control centre. The signals measured by PMUs are transmitted across Local and Wide Area Networks, where they may encounter excessive delays. Signal delays can have a disruptive effect and make applications at best inefficient and at worse ineffective. The main research contribution of this thesis is the performance evaluation of communication infrastructures for WAMS. The evaluation begins from inside substations and continues over wide areas from substations to control centre. Through laboratory-based investigations and simulations, the performance of communications infrastructure in a typical power system substation has been analysed. In addition, the performance evaluation of WAMS communications infrastructure has been presented. In the modelling and analysis, an existing WAMS as installed on the GB transmission system has been considered. The actual PMU packets as received at the Phasor Data Concentrator (PDC) were captured for latency analysis. A novel algorithmic procedure has been developed and implemented to automate the large-scale latency calculations. Furthermore, the internal delays of PMUs have been investigated, determined and analysed. Subsequently, the WAMS has been simulated and detailed comparisons have been performed between the simulated model results and WAMS performance data captured from the actual WAMS. The validated WAMS model has been used for analysing possible future developments as well as to test newly proposed mechanisms, protocols, etc. in order to improve the communications infrastructure performance

Accuracy and Reliability Improvement of Wide-Area Power Grid Monitoring

Phasor Measurement Unit (PMU) is one of the key elements of wide area measurement systems (WAMS) in advanced power system monitoring, protection, and control applications. Frequency Disturbance Recorder (FDR) developed by the Power IT Laboratory at the University of Tennessee, is a low-cost and single-phase PMU used at the distribution level. Traditional PMUs use GPS as the only timing source. They will stop working when GPS signal is lost or unstable. Two alternative GPS independent timing sources including eLoran and Chip Scale Atomic Clock were tested for long-term reliability and short-term accuracy to study the application of the two methods in synchrophasor measurement area. Phasor measurement accuracy is of great concern for power grid researchers and operators. The hardware and software measurement algorithm of the FDRs were analyzed to study the error sources. The hardware of the FDRs was upgraded based on the analysis to improve measurement accuracy. Further, two different phasor measurement algorithms that are based on discrete Fourier Transform (DFT) and signal model will be introduced, respectively. The aim is to improve the phasor measurement accuracy under different steady-state and dynamic conditions as well as in a real power grid environment at the distribution level. Moreover, to better evaluate the measurement accuracy of PMUs, a PMU testing system was built. A calibration method that can compensate the time delay of the PMU testing system was proposed, and the testing results were compared to NIST to verify the accuracy of the PMU testing system after calibration. At last, a concept of “Universal Grid Analyzer” (UGA) was proposed and a prototype was built. The UGA has improved phasor measurement accuracy thanks to the proposed adaptive high-accuracy synchronous sampling algorithm and high-precision ADC. Meanwhile, the UGA can also function as a synchronized power quality analyzer that has harmonics measurement, voltage sag and swell detection functions. Moreover, the noise analysis function of the UGA that can help the analysis of phasor measurement accuracy in a real power grid environment was developed

Estimation of Pulmonary Signal Using a Digital Camera

This work aims to facilitate detection of IC information, including serial number and company by reading the IC printed numbers from the manufacture using an image processing program. This project proposes a low-cost system for extracting IC information using a digital camera. The experiments were conducted on a DIP ICs at a different distance of 2 m and MATLAB® system were then compared with the data sheet of it. The experimental results show a promising performance in comparison with the data sheet from the manufacture, with low error rate

Co-design of Security Aware Power System Distribution Architecture as Cyber Physical System

The modern smart grid would involve deep integration between measurement nodes, communication systems, artificial intelligence, power electronics and distributed resources. On one hand, this type of integration can dramatically improve the grid performance and efficiency, but on the other, it can also introduce new types of vulnerabilities to the grid. To obtain the best performance, while minimizing the risk of vulnerabilities, the physical power system must be designed as a security aware system. In this dissertation, an interoperability and communication framework for microgrid control and Cyber Physical system enhancements is designed and implemented taking into account cyber and physical security aspects. The proposed data-centric interoperability layer provides a common data bus and a resilient control network for seamless integration of distributed energy resources. In addition, a synchronized measurement network and advanced metering infrastructure were developed to provide real-time monitoring for active distribution networks. A hybrid hardware/software testbed environment was developed to represent the smart grid as a cyber-physical system through hardware and software in the loop simulation methods. In addition it provides a flexible interface for remote integration and experimentation of attack scenarios. The work in this dissertation utilizes communication technologies to enhance the performance of the DC microgrids and distribution networks by extending the application of the GPS synchronization to the DC Networks. GPS synchronization allows the operation of distributed DC-DC converters as an interleaved converters system. Along with the GPS synchronization, carrier extraction synchronization technique was developed to improve the system’s security and reliability in the case of GPS signal spoofing or jamming. To improve the integration of the microgrid with the utility system, new synchronization and islanding detection algorithms were developed. The developed algorithms overcome the problem of SCADA and PMU based islanding detection methods such as communication failure and frequency stability. In addition, a real-time energy management system with online optimization was developed to manage the energy resources within the microgrid. The security and privacy were also addressed in both the cyber and physical levels. For the physical design, two techniques were developed to address the physical privacy issues by changing the current and electromagnetic signature. For the cyber level, a security mechanism for IEC 61850 GOOSE messages was developed to address the security shortcomings in the standard