The Smart Grid, regarded as the next generation power grid, uses two-way flows of electricity and information to create a widely distributed automated energy delivery network. In this article, we survey the literature till 2011 on the enabling technologies for the Smart Grid. We explore three major systems, namely the smart infrastructure system, the smart management system, and the smart protection system. We also propose possible future directions in each system. colorred{Specifically, for the smart infrastructure system, we explore the smart energy subsystem, the smart information subsystem, and the smart communication subsystem.} For the smart management system, we explore various management objectives, such as improving energy efficiency, profiling demand, maximizing utility, reducing cost, and controlling emission. We also explore various management methods to achieve these objectives. For the smart protection system, we explore various failure protection mechanisms which improve the reliability of the Smart Grid, and explore the security and privacy issues in the Smart Grid.

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Smart Grid — The New and Improved Power Grid: A Survey

Smart Grid - The New and Improved Power Grid:

Smart grid has modernized the way electricity is generated, transported, distributed, and consumed by integrating advanced sensing, communications, and control in the day-to-day operation of the grid. Electricity is a core utility for the functioning of society and for the services provided by information and communication technologies (ICTs). Several concepts of the smart grid, such as dynamic pricing, distributed generation, and demand management, have significantly impacted the operation of ICT services, in particular, communication networks and data centers. Ongoing energy-efficiency and operational expenditures reduction efforts in communication networks and data centers have gained another dimension with those smart grid concepts. In this paper, we provide a comprehensive survey on the smart grid-driven approaches in energy-efficient communications and data centers, and the interaction between smart grid and information and communication infrastructures. Although the studies on smart grid, energy-efficient communications, and green data centers have been separately surveyed in previous studies, to this end, research that falls in the intersection of those fields has not been properly classified and surveyed yet. We start our survey by providing background information on the smart grid and continue with surveying smart grid-driven approaches in energy-efficient communication systems, followed by energy, cost and emission minimizing approaches in data centers, and the corresponding cloud network infrastructure. We discuss the open issues in smart grid-driven approaches in ICTs and point some important research directions such as the distributed renewable energy generation capability-coupled communication infrastructures, optimum energy-efficient network design for the smart grid environment, the impact of green communication techniques on the reliability and latency requirements of smart grid data, workload consolidation with smart grid-awareness, and many more.

Energy-Efficient Information and Communication Infrastructures in the Smart Grid: A Survey on Interactions and Open Issues

The necessity to promote smart grid (SG) has been recognized with a strong consensus. The SG integrates electrical grids and communication infrastructures and forms an intelligent electricity network working with all connected components to deliver sustainable electricity supplies. Many advanced communication technologies have been identified for SG applications with a potential to significantly enhance the overall efficiency of power grids. In this paper, the challenges and applications of communication technologies in SG are discussed. In particular, we identify three major challenges to implement SG communication systems, including standards interoperability, cognitive access to unlicensed radio spectra, and cyber security. The issues to implement SG communications on an evolutional path and its future trends are also addressed. The aim of this paper is to offer a comprehensive review of state-of-the-art researches on SG communications.

Smart Grid Communication: Its Challenges and Opportunities

Many operations in power grids, such as fault detection and event location estimation, depend on precise timing information. In this paper, a novel Time Synchronization Attack (TSA) is proposed to attack the timing information in smart grid. Since many applications in smart grid utilize synchronous measurements and most of the measurement devices are equipped with global positioning system (GPS) for precise timing, it is highly probable to attack the measurement system by spoofing the GPS. The effectiveness of TSA is demonstrated for three applications of phasor measurement unit (PMU) in smart grid, namely transmission line fault detection, voltage stability monitoring and event locationing. The validity of TSA is demonstrated by numerical simulations.

Time Synchronization Attack in Smart Grid: Impact and Analysis

Recent developments in smart grid technology have spawned interest in the use of phasor measurement units to help create a reliable power system transmission and distribution infrastructure. Wide-area monitoring systems (WAMSs) utilizing synchrophasor measurements can help with understanding, forecasting, or even controlling the status of power grid stability in real-time. A power system frequency monitoring network (FNET) was first proposed in 2001 and was established in 2004. As a pioneering WAMS, it serves the entire North American power grid through advanced situational awareness techniques, such as real-time event alerts, accurate event location estimation, animated event visualization, and post event analysis. Several papers published in the past several years discussed the FNET structure and its functionality. This paper presents some of the latest implementations of FNET's applications, which add significant capacities to this system for observing power system problems.

Wide-Area Frequency Monitoring Network (FNET) Architecture and Applications

This paper presents an adjustable robust co-optimization model for energy and ancillary service markets joint dispatch considering wind power uncertainties in real-time electricity markets. The participation factors are employed to generate adjustable generation outputs and ensure energy balance. The proposed robust optimization model can be equivalently transformed into a large-scale linear programming model with a huge number of dummy variables and additional constraints that challenge real-time markets. To further reduce the computation burden, the redundant constraint reduction strategy is proposed to fast eliminate redundant transmission security constraints before solving the model. The results from the IEEE 30-bus system with two wind farms show that the proposed robust joint optimization model provides a better solution compared to those cases using sequential dispatch or deterministic dispatch methodologies. Additional results from practical large-scale systems suggest that the number of redundant constraints is less than 6%, indicating the effectiveness of the proposed redundant constraint reduction strategy in improving the computation efficiency of the robust joint dispatch in real-time markets.

Robust Co-Optimization to Energy and Ancillary Service Joint Dispatch Considering Wind Power Uncertainties in Real-Time Electricity Markets

Based on the inherent characteristic of the carrier-based pulse-width modulation converters, the response of the first carrier frequency harmonic (FCFH) current in the voltage source converter (VSC)-based high-voltage direct current (HVDC) transmission system is analysed under different fault conditions in this paper. A new protection scheme for the VSC-based HVDC transmission systems is proposed based on the FCFH currents. By extracting the harmonic currents at both the endings of the DC transmission cable, the fault type can be identified. The VSC-based HVDC test system is modelled in the PSCAD/EMTDC and the proposed protection scheme is evaluated with a variety of values of the fault resistance and the fault locations. Comprehensive test studies show that the performance of the proposed protection scheme is inspiring. It can recognise the internal and the external faults correctly.

https://ietresearch.onlinelibrary.wiley.com/doi/epdf/10.1049/iet-gtd.2013.0377

Harmonic current protection scheme for voltage source converter-based high-voltage direct current transmission system

Transmission line parameter modeling and PMU measurement calibration are important research topics in power system engineering. State estimation is widely used to estimate voltage with assumption of “accurate” system parameters. Various methods have also been proposed to estimate line parameters based on PMU measurements. However, neither system parameters nor system measurements are reliable enough to be used to estimate each other separately. To solve this problem, this paper proposes a novel method that can simultaneously estimate line parameters as well as measurements. This method requires PMUs installed at both terminals of the transmission lines. It also requires only one bus with accurate voltage measurements and accurate current measurements. These accurate measurements can be achieved by pre-calibrated PMU receiving signals from pre-calibrated current transformers and voltage transformers. Accurate line parameters and measurements estimated by this method can be used to improve state estimation, power system monitoring and protection and several other applications.

Simultaneous transmission line parameter and PMU measurement calibration

Phasor Measurement Units (PMUs) utilize three-phase current and voltage transformers to obtain input signals from which the phasors are estimated. In general the instrument transformers have Ratio Correction Factors (RCFs) which can be determined by conducting on-site calibration tests. These calibration tests are expensive and time-consuming and rarely performed on a system-wide basis. The errors introduced by the unknown RCFs are assumed to be a part of the overall measurement error. A novel approach of the Wide Area Measurement System (WAMS) is to use the phasor measurements to automatically calibrate all the instrument transformers from which phasor data is obtained. This technique is based upon having access to at least one set of three phase voltage transformers (reference transformers) with known accurate Ratio Correction Factors. Potential Transformers (PTs) or special accurate Capacitive Voltage Transformers (CVTs) are often available as a source of reference for this purpose. This paper explains the theory of this calibration procedure, and using simulations on a power system model. It is shown that very accurate RCFs of all the current and voltage transformers can be obtained. This calibration function is being implemented on the Dominion Virginia Power (DVP) System. It is of course implied that any other measurement system - for example SCADA - which uses the same instrument transformers will benefit from this calibration procedure.

Zhongyu Wu

Papers

Wide-Area Frequency Monitoring Network (FNET) Architecture and Applications

Robust Co-Optimization to Energy and Ancillary Service Joint Dispatch Considering Wind Power Uncertainties in Real-Time Electricity Markets

Harmonic current protection scheme for voltage source converter-based high-voltage direct current transmission system

Simultaneous transmission line parameter and PMU measurement calibration

Three-phase instrument transformer calibration with synchronized phasor measurements