Smart Grid Protection Research Articles

A new developed smart grid protection technique with wind farms based on positive sequence impedances and current angles

The wind farms penetration in power systems has an adverse impact on transmission lines system protection due to the characteristics of wind farms that are different from the conventional sources during fault occurrence. Different factors such as the distributed generation concept, the own behavior of the wind generator, variation of wind farm impedance during faults inside the farm, and varying wind speed arise different challenges regarding the behavior of the relay protection. The paper introduces a novel protection technique based on total positive sequence impedance and positive sequence current angles through wide area monitoring system. A new protection-setting contour with an efficient and capacity to identify the faulted zone during different fault conditions is developed. The proposed protection scheme tripping action has to fulfil the fault ride through capability (FRT). The results showed a simple and robust new protection system for such smart grid configuration system with wind farms.

Synchrophasor Measurement-Assisted System Integrity Protection Scheme for Smart Power Grid

Rapid penetration of novel cutting-edge technologies into power grids has paved a way for new opportunities besides challenges. Though the conventional system integrity protection schemes (SIPS) are performing well, they may not be adequate for the high-end protection of smart power grid (SPG) due to increasing complexity. This paper proposes a synchrophasor measurement-assisted SIPS method for the high-end protection of SPG. It employs synchronized voltage and current phasor data, acquired at phasor data concentrator (PDC) of wide-area supervisory protection system (WASPS) from all phasor measurement units (PMU), to detect the disturbance, identify disturbed area and locate the sensitive region (SR). Further, the proposed scheme classifies fault and stressed conditions using the estimated peak time (Tp_est) and time of settling (Ts_est) from the voltage phasor oscillations. The functioning of the proposed method has been illustrated through various case studies carried on Kundur’s two-area model. Furthermore, the efficacy of the proposed method has been validated on the New England IEEE-39 bus system in MATLAB/Simulink environment. The results show that the proposed method is efficient in enhancing the system integrity protection (SIPS) and situational awareness (SA) in SPG. In addition, it improves the protection system reliability (PSR).

Measurement and Analysis of PMU Reporting Latency for Smart Grid Protection and Control Applications

Emerging power system protection and control applications require faster-responding measurements and more accurate knowledge of the actual latency of the measurement and communications systems. A new method for accurately determining the reporting latency of a phasor measurement unit (PMU) has been developed and demonstrated. This method operates in real-time, works passively for any existing PMU without requiring changes to the PMU hardware or software, and it is very accurate - providing a measurement uncertainty of i500 ns in many cases, significantly surpassing the 0.002 s accuracy requirement in the most recent IEEE Synchrophasor standard. Only low-cost hardware and open source software are required. It is particularly important to understand end-to-end system latency, including the impact of local and wide-area communications, rather than just the latency of the PMU device; the proposed method also supports such practical measurements. It is therefore shown how this advance can be used to enable efficient, but realistic, cross-domain power system simulation studies, which incorporate measurement and communications delays. These capabilities address complexity and uncertainty in the design and operation of future PMU-based protection and control functions for new smart grid services.

TORUS

Cyber-Physical Systems (CPS) contain intertwined and distributed software, hardware, and physical components to control complex physical processes. They find wide application in industrial systems, such as smart grid protection systems, which face increasingly complex communication and computation needs. Due to the scale and complexity of the interactions that occur within CPS, tracing requirements through to the system components and software code that implement them is often hard. Existing requirements management systems do not scale well, and traceability is difficult to implement and maintain in highly heterogeneous systems. However, the information trace that links provide is crucial for supporting testing and certification activities in safety-critical environments such as smart grids. The well-formed models of power systems provided by the IEC 61850 standard and the software design structure provided by the IEC 61499 Function Blocks standard can be leveraged to automate many traceability operations. We present Traceability of Requirements Using Splices (TORUS), a novel traceability framework for the development of large-scale safety-critical CPS. TORUS introduces splices , autonomous graph-based data structures that automatically create and manage trace links between requirements and components through the inevitable changes that occur during system development. The formal, graph-based structure of TORUS lends itself well to the development of sophisticated algorithms to automate the extraction of useful traceability information such as historical records and metrics for requirements coverage and component coupling. By capturing not only the current state of the system but also historical information, TORUS allows project teams to see a much richer view of the system and its artifacts. We apply TORUS to the development of a protection system for smart grid substations. In addition, through a number of experiments in splice creation, modification, and application of automated algorithms, we show that TORUS scales easily to large systems containing hundreds of thousands of requirements and system components and millions of possible trace links.

Blockchain-Based Secure Equipment Diagnosis Mechanism of Smart Grid

The smart terminal and grid protection devices play a very important role in the safe operation of the smart grid. Traditional maintenance and renewal of the center node wastes a lot of manpower and material resources and have huge safety implications. This paper proposes a safety equipment diagnosis mechanism based on consortium blockchain technology to realize more efficient, convenient, and secure device maintenance. When a device has problems or notices improper operation, it can make a device diagnosis request in the consortium blockchain network, and receive a diagnosis response from a vendor or non-original supplier nodes. This scheme designs a decentralized safety equipment diagnosis smart contract, combining response node bid price and credit, and applies a multi-dimensional reverse auction mechanism to determine bid node and transaction price. After a smart device diagnosed, the relevant message will be packaged and sent to a smartphone, which can use the client to set up the smart contract of equipment operation policy. Paillier encryption arithmetic can be used to ensure device diagnosis mechanism safety. The proposed scheme is guaranteed not to reveal sensitive information in the process of device interaction.

Precision Measurement System for the Calibration of Phasor Measurement Units

Phasor measurement units (PMUs) are used for monitoring, protection, and control of smart grids. Characterization of PMUs to national standards of measurement is important to assure reliability and consistency of PMUs across the industry and is required by documentary standards. At the National Measurement Institute, Australia, we have developed a calibration system to provide some calibration points for the characterization of PMUs under steady-state conditions that can be compatible with standard tests. This paper describes the operation and calibration of the system with emphasis on traceability to national standards of measurement.

Legal problems for the protection of smart grids from cyber threats

Legal problems for the protection of smart grids from cyber threats

A nifty collaborative intrusion detection and prevention architecture for Smart Grid ecosystems

Smart Grid (SG) systems are critical, intelligent infrastructure utility services connected through open networks that are potentially susceptible to cyber-attacks with very acute security risks of shutdown, loss of life, and loss of revenue. Traditional intrusion detection systems based on signature and anomaly techniques are no longer sufficient to protect SGs due to their new connectivity and management challenges, the ever-rapidly-evolving masquerades, and cyber criminality levied against them. SGs require cyber-security systems to render them resilient and protected through advanced Intrusion Detection and Prevention System (IDPS) techniques and mechanisms. This paper proposes a smart collaborative advanced IDPS to provide the best possible protection of SGs with a fully distributed management structure that supports the network and host based detections and the prevention of attacks. By facilitating a reliable, scalable, and flexible design, the specific requirements of IDPS for SGs can be more easily met via a fuzzy risk analyzer, an independent and ontology knowledge-based inference engine module. These can work collaboratively by managing functions across multiple IDPS domains. A set of extensive and intensive simulated experiments shows that with its smart advanced components incorporating soft computing machine-learning techniques and a rich ontology knowledge base with fuzzy logic analysis, it detects and prevents intrusions more efficiently. The multi-faceted results of the simulation also show that the proposed Collaborative Smart IDPS (CSIDPS) system increases the intrusion detection accuracy and decreases the false positive alarms when compared to traditional IDPSs. This is epitomized by the skillful use of the confusion matrix technique for organizing classifiers, visualizing their performance, and assessing their overall behavior. In the final analysis, the CSIDPS architecture is designed toward contributing to de facto norms for SG ecosystems.

Fault Diagnosis for Smart Grids in Pragmatic Conditions

Due to the advancements of electrical networks, the operators are able to employ a gamut of information for assessing the state of the infrastructure facilitating diagnosis of potential malfunctions appearing in one or more components of the grid. This paper presents a cognitive fault diagnosis framework for smart grids (SGs) which exploits the temporal and functional relationships existing within the datastreams coming from the nodes of the network. The protection of SGs can rely not only on conventional techniques (e.g., circuit breakers) but also on processing information which is available, thanks to the information and communication layer. We propose a framework which is able to autonomously learn the model of the nominal state using the respective data by means of hidden Markov models operating in the parameter space of linear time-invariant models. Subsequently, the framework is able to detect data not belonging to the nominal state and localize the potential fault at the cognitive level. The isolation is based on a graph representation of the SG revealing the correlations among the nodes based on the Granger causality. We conducted thorough experiments on the IEEE-9 bus system model achieving encouraging results in terms of false positive/negative rate and detection/isolation delay.

A Model Checking Approach to Testing the Reliability of Smart Grid Protection Systems

As distributed, communication-based protection systems become more prevalent in the emerging smart grid, the task of critically assessing their reliability has become increasingly challenging due to the complexity of their underlying software designs. This paper demonstrates that the discipline of software model checking can be applied to smart grid protection software designs to rigorously assess their fault tolerance. In this paper, the SPIN model checker is applied to a published wide-area backup protection system (WABPS). The WABPS was specifically architected to be highly reliable under various kinds of common failure scenarios, including mechanical malfunctions, erroneous sensor readings, and communication failures. However, because of its built-in redundancy and decentralized peer-to-peer design, calculating its precise fault tolerance is nontrivial. This paper shows how SPIN can be applied to the WABPS's design to brute-force prove the limits of the number and types of failures that can occur while the system remains able to successfully perform its function. This same technique is applicable to a wide variety of smart grid protection software designs, and the information it provides is invaluable to protection engineers during the development of new systems, for assessing the quality of competing designs, and for risk management purposes.

A Trust-Management Toolkit for Smart-Grid Protection Systems

This paper discusses the trust-management toolkit, which is a robust and configurable protection system augmentation, which can successfully function in the presence of an untrusted (malfunctioning) smart grid (i.e., communication-based, protection system nodes). The trust-management toolkit combines reputation-based trust with network-flow algorithms to identify and mitigate faulty smart-grid protection nodes. The toolkit assigns trust values to all protection nodes. Faulty nodes, attributed to component or communication system malfunctions (either intentional or unintentional), are assigned a lower trust value, which indicates a higher risk of failure to mitigate detected faults. The utility of the toolkit is demonstrated through simulations comparing “enhanced” backup and special protection systems to original “unenhanced” systems via an analysis of variance analysis. The results show promise for the toolkit in the smart-grid protection system.

Developing Educational Smart Grid Laboratory for the UAEU

The goal of this paper is to present the first stage of developing an educational laboratory to teach smart grid design and implementations for both under graduate and graduate levels. Hampden 180 simulator that represents conventional generation, transmission, and distribution power system is integrated with intelligent electronic devices and tied together in an architecture that provides reliable and fault-tolerant protection, control and monitoring. The upgraded laboratory will demonstrate high level of functionality and satisfying the design and operation objectives of smart grid metering, protection, control, monitoring and communication. Part 2 of this paper will discuss and present the implementation stage.

The Research on Information Architecture and Security Protection of Smart Grid

Information and communication technology is one of the key issues of smart grid and the basis of its realization. To standardization of smart grid information architecture, this paper analyzes smart grid conceptual reference model, propose smart grid hierarchical information architecture, including grid equipment layer, communication gird layer, data storage layer and data application layer. For this information architecture, this paper finally discusses smart gird protection system.

Operation of Multi DC Smart Grids Based on Renewable Energy Sources and Protection of DC Transmission Line

Abstract This paper presents the operation under fault and protection of multi DC smart grids connected to the DC transmission line. The smart grid consists of wind turbine and photovoltaic generators, controllable loads, generator side and grid side inverters. The voltage stability of the DC bus voltage is attained by applying the power consumption control of controllable loads, the power control of grid connected converter and power control of renewable plants. On the other hand, the fault protection for short-circuit and low resistance ground fault at the DC transmission line was sighted. Simulation results based on PSIM are provided to demonstrate the effectiveness of the system.

Energy Efficient Security Algorithm for Power Grid Wide Area Monitoring System

Modern power grid is the most complex human-made system, which is monitored by wide-area monitoring system (WAMS). Providing time-synchronized data of power system operating states, WAMS will play a crucial role in next generation smart grid protection and control. WAMS helps secure efficient energy transmission as well as reliable and optimal grid management. As the key enabler of a smart grid, numerous sensors such as PMU and current sensors transmit real-time dynamic data, which is usually protected by encryption algorithm from malicious attacks, over wide-area-network (WAN) to power system control centers so that monitoring and control of the whole system is possible. Security algorithms for power grid need to consider both performance and energy efficiency through code optimization techniques on encryption and decryption. In this paper, we take power nodes (sites) as platforms to experimentally study ways of energy consumptions in different security algorithms. First, we measure energy consumptions of various security algorithms on CrossBow and Ember sensor nodes. Second, we propose an array of novel code optimization methods to increase energy consumption efficiency of different security algorithms. Finally, based on careful analysis of measurement results, we propose a set of principles on using security algorithms in WAMS nodes, such as cryptography selections, parameter configuration, and the like. Such principles can be used widely in other computing systems with energy constraints.

Thermal Management of High Density Power Electronics Modules Using Dielectric Mineral Oil With Applications in the Electric Utility Field for Smart Grid Protection

The thermal management of high density power electronics can be extremely challenging due to high power loads paired with small device footprints. When these power electronics are used in systems, which require extremely high reliability, the design of the thermal abatement system takes on increasing importance. In this study, the thermal response of a solid state fault current limiter is analyzed in steady-state and failure mode to develop a thermal solution which is both economical and reliable. The solid state fault current limiter is used in electric distribution systems to prevent a current surge from reaching sensitive equipment downstream of a power plant in the event of a disturbance on the line. A parametric study on several design variables including power loading, device spacing, and system flowrate is completed to give insight into the development of an optimal design. A coldplate design using dielectric mineral oil, which minimizes both system footprint and operating cost, is developed. This analysis and thermal management solution is applicable not only to this situation but also to the other high density power electronics applications.