Smart grid is a promising power delivery infrastructure integrated with communication and information technologies. Its bi-directional communication and electricity flow enable both utilities and customers to monitor, predict, and manage energy usage. It also advances energy and environmental sustainability through the integration of vast distributed energy resources. Deploying such a green electric system has enormous and far-reaching economic and social benefits. Nevertheless, increased interconnection and integration also introduce cyber-vulnerabilities into the grid. Failure to address these problems will hinder the modernization of the existing power system. In order to build a reliable smart grid, an overview of relevant cyber security and privacy issues is presented. Based on current literatures, several potential research fields are discussed at the end of this paper.

https://repository.um.edu.mo/bitstream/10692/2883/3/Liu-2012-Cyber-security-and-privacy-issues-i.pdf

Cyber Security and Privacy Issues in Smart Grids

There has been much recent discussion on what distribution systems can and should look like in the future. Terms related to this discussion include smart grid, distribution system of the future, and others. Functionally, a smart grid should be able to provide new abilities such as self-healing, high reliability, energy management, and real-time pricing. From a design perspective, a smart grid will likely incorporate new technologies such as advanced metering, automation, communication, distributed generation, and distributed storage. This paper discussed the potential impact that issues related to smart grid will have on distribution system design.

Impact of Smart Grid on distribution system design

The conventional unified power-flow controller (UPFC) that consists of two back-to-back inverters requires bulky and often complicated zigzag transformers for isolation and reaching high voltage. This paper proposes a completely transformer-less UPFC based on an innovative configuration of two cascade multilevel inverters (CMIs). The unique configuration and control of the two CMIs as a power-flow controller make it possible to independently control active and reactive power flows over a line. The new UPFC offers several advantages over the traditional technology, such as transformer-less, light weight, high efficiency, high reliability, low cost, and fast dynamic response. The transformer-less UPFC is thereby very suited for fast and distributed power flow control, such as wind and solar power transmission. Experimental results based on 13.8-kV/2-MV·A transformer-less UPFC prototype are shown to validate the theoretical analysis and operating principle.

Transformer-Less Unified Power-Flow Controller Using the Cascade Multilevel Inverter

Smart grid is a promising power infrastructure that is integrated with communication and information technologies. Nevertheless, privacy and security concerns arise simultaneously. Failure to address these issues will hinder the modernization of the existing power system. After critically reviewing the current status of smart grid deployment and its key cyber security concerns, the authors argue that accountability mechanisms should be involved in smart grid designs. We design two separate accountable communication protocols using the proposed architecture with certain reasonable assumptions under both home area network and neighborhood area network. Analysis and simulation results indicate that the design works well, and it may cause all power loads to become accountable.

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Achieving Accountability in Smart Grid

The cognitive radio-based sensor network (CRSN) is envisioned as a strong driver in the development of modern power system smart grids (SGs). This can address the spectrum limitation in the sensor nodes due to interference cause by other wireless devices operating on the same unlicensed frequency in the Industrial, Scientific and Medical band. These sensor nodes are used for monitoring and control purposes in various components of a SG, ranging from generation, transmission, and distribution, and down to the consumer, including monitoring of utility network assets. A reliable SG communication network architecture is required for transferring information which needed by the SG applications, alongside the monitoring and control by CRSN. Hence, this paper investigates and explores the CRSN conceptual framework, and SG communication architecture with its applications; vis-a-vis the communication access technologies, including implementation design with quality of service support. Consequently, this paper highlights various research gaps, such as implementation design model, utilization of LPWAN for CRSN based SG deployment, and so on. This includes discussion on the future direction for various aspects of the CRSN in SG. To address these research gaps, we introduced a smart unified communication solution to improve the efficiency of the SG and mitigate various associated challenges.

Cognitive Radio Based Sensor Network in Smart Grid: Architectures, Applications and Communication Technologies

The power grid is aging and under stress. Unlike other modern networked systems, the grid lacks intelligence and automation. This paper has presented a new look at the way a Smart Grid can be implemented. The conventional approach has been to first obtain real time information on critical parameters, and then by controlling VAR resources, tap changers, and FACTS devices to achieve the desired control. A simpler approach is presented here based on using highly interconnected meshed networks. Such networks have been used in high density urban areas for many years for the high reliability achievable, but suffer from poor line utilization and lack of flexibility under contingency or load growth conditions. The use of a large number of Current Limiting Conductor or CLiC modules provides a simple and cost-effective approach for realizing a controllable meshed network, maximizing network capacity under diverse contingencies and load growth scenarios. Using a low-tech approach, it is seen that basic network performance and reliability are dramatically increased. It is also seen that the distributed nature and inherent redundancy in the deployment of large numbers of CLiC modules, results in high system reliability.

H. Johal

Papers

A Smarter Grid for Improving System Reliability and Asset Utilization