Substation Network Research Articles

MATHEMATICAL COMPUTER-BASED MODELS OF RAILWAY TRACTION SUBSTATIONS COMPUTER NETWORKS INFORMATION SECURITY

Based on the analysis of the complex security issues oflocal area networks railway traction substations information resources shown that generally accepted in the world is thedirection of intellectualization of computer networks, as abasis for improving the safety of railway transport and the development of advanced energy-saving technologies ofelectricity consumption. Formed logical structure of a localarea network operational management of power supply inthe form of a graph that displays the topological characteristics of traction substation, and also developed amathematical model of it in the form of systems ofdifferential equations. Applied modern methods of differential transformations to determine the probabilitiesof the states of nodes of the graph representing the localarea network of traction substation. Formulated criteria forinformation security and provided strategies for ensuringthe principle of minmax. The necessary and sufficient conditions for an extremum, which opens up the possibility of finding the optimal search strategy. Showed the necessary and sufficient conditions for an extremum, which opens up the possibility of finding the optimal searchstrategy.

Intrusion Evaluation of Communication Network Architectures for Power Substations

Electronic elements of a substation control system have been recognized as critical cyberassets due to the increased complexity of the automation system that is further integrated with physical facilities. Since this can be executed by unauthorized users, the security investment of cybersystems remains one of the most important factors for substation planning and maintenance. As a result of these integrated systems, intrusion attacks can impact operations. This work systematically investigates the intrusion resilience of the ten architectures between a substation network and others. In this paper, two network architectures comparing computer-based boundary protection and firewall-dedicated virtual local-area networks are detailed, that is, architectures one and ten. A comparison on the remaining eight architecture models was performed. Mean time to compromise is used to determine the system operational period. Simulation cases have been set up with the metrics based on different levels of attackers’ strength. These results as well as sensitivity analysis show that implementing certain architectures would enhance substation network security.

Balancing Energy in the Smart Grid Using Distributed Value Function (DVF)

As the penetration of renewable energy resources increases in distribution networks, so does the need to manage these resources in an effective manner. Since these resources are installed to displace carbon-based generation and to provide an income stream to the resource owner, it is important that both installation objectives (as a minimum) can be met. With all of these renewable energy resources available, the opportunity also exists to assist with the energy management of this resource-rich distribution network. However, the renewable energy resources do not produce power in a deterministic manner. The available production depends on the time of day and many other environmental factors. Accordingly, a system that is able to program and coordinate the production and storage of power in a distribution network would be of benefit to the network operator. This paper presents a multiagent system (MAS) that is responsible for the management of renewable energy resources and power storage systems connected to the distribution network of a zone substation. The MAS manages the orderly connection and disconnection of resources using a plug and play algorithm in order to minimize disturbances to the supply-and-demand balance within the distribution network. The proposed MAS design is validated using a network based on the IEEE 34-bus test feeder. The results obtained through computer simulation show that with the MAS, it is possible to manage the power resources so that there is minimal power drawn from the upstream network during periods of high demand.

Implementation and Application of QoS in Power Ethernet Switch

Smart grid based on Ethernet technology is the development direction of power transmission network, power Ethernet carried different data communication service, which have different needs for network transmission time delay and bandwidth guarantee, which is reflected in the quality of service of network QoS (Quality of Service) requirements, in power Ethernet, QoS which can provided differentiated services (Diff-Serv) is essential. This paper outlines QoS implementation, QoS feature and related technologies in the power Ethernet switch, and analyses the flow characteristics of digital substation network, and proposes classification and scheduling scheme of service traffic based on network nodes, and elaborates an important effect that QoS has in ensuring substation communication network transmission of high quality service.

Effect of Substation Network on Transformer PD Monitoring

In this paper, a simulation model for the propagation of transformer PD pulse has been constructed,and the propagation of PD in a real substation were investigated. We also studied the frequency characteristics of currents at different detection positions, and the influences of substation network are analyzed in aspects of system resonant frequency. The optimal detection position and the optimal measuring band are proposed. The results show that, the calculated range of substation network and capacitive apparatus play the key roles in impedance characteristics.

An IEC61850 Communication Model for Network Devices in Smart Substation

This paper proposes an IEC61850 communication model for the network devices in smart substation based on the substation network status monitoring requirements through bringing the network device status information management into a unified monitoring and management system of smart substation. The substation monitoring system can directly get the state information and configuration information of the communication network and network devices, such as link status, bandwidth status, port forwarding state, the port packet loss rate, bit error rate and so on.

Advanced Applied Research of Smart Substation Based on Multi-Element Data

The real time synchronous sampling of large basic data information and the networking information sharing have laid necessary foundation for smart substation advanced application. The advanced application of smart substation is the multi-index optimization analysis and control strategy research which based on digitization of information transmission and networking of information sampling. This paper aimed at health state analysis and control strategy research of substation equipment and network environment, which based on the theory of multi-element data analysis and double network and double measuring and control.

System Tests for IEEE 1588 Standard Profile in Power System Applications

The main objective of this study is to establish the methods of system tests for the IEEE PC37.238 compliant devices. Aiming at the application in power system, a common profile called IEEE PC37.238 is defined in IEEE 1588 Precision Time Protocol (PTP). However, the standard doesn’t provide specifications for system testing. In this study viable metrics and test methods are established to help to verify the ability of the substation network to meet the power industry's accuracy, reliability criteria defined in PC37.238. The test configurations and method implementations for measuring conformance are designed. Moreover, details on the tests for the path delay mechanism and BMC algorithm are given as an example in terms of testing methodology, procedures and analysis of the results.

Modelling and analysis of protection and control applications in smart substation

The real-time transaction processing was a key and challenging technology to protect systems from various failures in smart substation. This paper introduces the time critical communication between the protection and control devices and the primary apparatuses in three-level communication network architecture based on IEC61850, and analyses the process of information exchange and delay requirement of Protection and Control P&C applications between level and level, bay and bay, station and station in smart substation. The generic model of the P&C applications was modelling by latency requirement on OPNET, then the simulation and discussion on using those models to construct IEC61850 network validated the real-time of the application model. In the meantime, the delay performance of the P&C application is analysed in scenarios multiple services sharing substation network, which is an attempt to discuss the possibility of establishing a smart substation network simulation platform on OPNET.

Real Time Closed-loop Test Rig for Decentralized Control of Smart Distribution Networks

Electric power grids are moving towards Smart Grids and many new energy sources and loads are being integrated into distribution networks requiring the network to become more active and smart. The distribution networks have not been designed to cope with new constraints set up by the new energy sources and complex loads and will result in a number of adverse impacts. There is a considerable need for developing new algorithmic solutions for decentralised control within distribution networks and validating them at laboratory level before they can be successfully applied in the power grid. This research work addresses the development of a real time test rig which provides a decentralised control environment in distribution networks, onto which data management and network control functions are able to be implemented in a closed loop fashion, to observe their performance. This work also describes the development of a substation network controller; a platform that provides a closed loop test system for research, development, testing and validation of real time distribution network management and control functions.

The Multi-criterion Relay Technology of Power Distribution System Based on GOOSE

GOOSE network of intelligent substation provides the fast packet transmission channel for the substation automation system, each IED connected in the GOOSE network can choose as subscribers or publishers to receive or publish data in order to achieve the station information sharing and equipment interoperability. In this paper, a 10kV bus protection scheme is proposed by combining intelligent substation requirements and the technical characteristics of the GOOSE protocol. This scheme uses intelligent substation information sharing and it is an application of GOOSE technology. A single-phase ground protection scheme is also proposed. It’s based on the GOOSE technology. Fault information is in GOOSE message, so all the IEDs can share it through the bay layer network .At last, this paper proposes the execution scheme for upgrading the traditional protection. DOI: http://dx.doi.org/10.11591/telkomnika.v11i12.3742

IEC 61850 변전소 네트워크에서의 이상 징후 탐지 연구

본 논문에서는 IEC 61850 기반 자동화 변전소 네트워크에서의 이상 징후 탐지를 위한 MMS/GOOSE 패킷 정상행위 프로파일링 방법을 제안한다. 기존에 주로 사용되고 있는 시그니처(signature) 기반의 보안 솔루션은 제로데이(zero-day) 취약점을 이용한 APT 공격에 취약에 취약할 수밖에 없다. 최근 제어시스템 환경에서의 이상 탐지(anomaly detection) 연구가 이뤄지고 있지만, 아직까지 IEC 61850 변전소 환경에서의 이상 탐지에 대한 연구는 잘 알려져 있지 않다. 제안하는 기법은 MMS/GOOSE 패킷에 대한 3가지 전처리(3-phase preprocessing) 방법과 one-class SVM 알고리즘을 이용한 정상 행위 모델링 방법을 포함한다. 본 논문에서 제시하는 방법은 IEC 61850 변전소 네트워크에 대한 APT 공격 대응 솔루션으로 활용될 것을 기대한다. This paper proposes normal behavior profiling methods for anomaly detection in IEC 61850 based substation network. Signature based security solutions, currently used primarily, are inadequate for APT attack using zero-day vulnerabilities. Recently, some researches about anomaly detection in control network are ongoing. However, there are no published result for IEC 61850 substation network. Our proposed methods includes 3-phase preprocessing for MMS/GOOSE packets and normal behavior profiling using one-class SVM algorithm. These approaches are beneficial to detect APT attacks on IEC 61850 substation network.

Application of WLAN Information Transmission and System Security Technology in the Smart Substation Network

Since smart grid construction started, the intelligent substation network has become the hot topic. This paper combined with IEC61850 in the smart substation data sampling, analyzes the frequency and bandwidth characteristics of the wireless network for the current smart substation missing information content. It studies the application of wireless network reliability verification. The article discusses the application program from three following important respects: the WLAN design coverage, flow and load, application needs. It describes the key problems of the wireless network data sampling implement from the data sampling time. At the same time the futures application of the wireless network sampling in the smart substation is prospected.

Performance Analysis of PTP Components for IEC 61850 Process Bus Applications

New substation automation applications, such as sampled value (SV) process buses and synchrophasors, require a sampling accuracy of 1 μs or better. The Precision Time Protocol (PTP), IEEE Std. 1588, achieves this level of performance and integrates well into Ethernet-based substation networks. This paper takes a systematic approach to the performance evaluation of commercially available PTP devices (grandmaster, slave, transparent, and boundary clocks) from a variety of manufacturers. The “error budget” is set by the performance requirements of each application. The “expenditure” of this error budget by each component is valuable information for a system designer. The component information is used to design a synchronization system that meets the overall functional requirements. The quantitative performance data presented show that this testing is effective and informative. Results from testing PTP performance in the presence of SV process bus traffic demonstrate the benefit of a “bottom-up” component testing approach combined with “top-down” system verification tests. A test method that uses a precision Ethernet capture card, rather than dedicated PTP test sets, to determine the correction field error of transparent clocks is presented. This test is particularly relevant for highly loaded Ethernet networks with stringent timing requirements. The methods presented can be used for development purposes by manufacturers or by system integrators for acceptance testing. An SV process bus was used as the test application for the systematic approach described in this paper. The test approach was applied, components were selected, and the system performance was verified to meet the application's requirements. Systematic testing, as presented in this paper, is applicable to a range of industries that use, rather than develop, PTP for time transfer.

Research on Fault Diagnosis Model for Substation with Redundancy Protection Based on Petri Net

Due to layering distribution, double network and dual-disposition characteristics of 750kV substation, Petri net diagnosis model which based on redundant protection for substation is proposed. In this model, a redundant knowledge representation method is adopted from components to the local and the whole, then components redundant diagnosis-model is constructed on basis of it. The model can be decomposed into main and redundant subnet-model based on Petri net by using two sets of protective device information, and considered remote backup protection, which realize fault tolerance of dual-machine. Through information fusion of redundant diagnosis model of components, the local and the overall model is established. The results show that the model achieves high efficiency and reliability.

Application-aware secure multicast for power grid communications

We propose an application-aware approach to setting up secure multicast groups for power grid communications that automatically derives group memberships and verifies configuration conformance from data dependencies in system specifications. We design an abstract multicast model, analysis algorithms, and configuration derivation techniques. These are implemented in a prototype system, SecureSCL. We also provide experimental evidence that IPsec multicast can address latency constraints in power substation networks.

Vulnerability Assessment of Cybersecurity for SCADA Systems

Vulnerability assessment is a requirement of NERC's cybersecurity standards for electric power systems. The purpose is to study the impact of a cyber attack on supervisory control and data acquisition (SCADA) systems. Compliance of the requirement to meet the standard has become increasingly challenging as the system becomes more dispersed in wide areas. Interdependencies between computer communication system and the physical infrastructure also become more complex as information technologies are further integrated into devices and networks. This paper proposes a vulnerability assessment framework to systematically evaluate the vulnerabilities of SCADA systems at three levels: system, scenarios, and access points. The proposed method is based on cyber systems embedded with the firewall and password models, the primary mode of protection in the power industry today. The impact of a potential electronic intrusion is evaluated by its potential loss of load in the power system. This capability is enabled by integration of a logic-based simulation method and a module for the power flow computation. The IEEE 30-bus system is used to evaluate the impact of attacks launched from outside or from within the substation networks. Countermeasures are identified for improvement of the cybersecurity.

The Dryland Agriculture Applied Research Project in Morocco: A Perspective 12 Years after Completion

The Dryland Agriculture Applied Research Project (DAARP) in Morocco (1978-1994) was a joint partnership between USAID, the Mid-America International Agricultural Consortium (MIAC) involving five U.S. universities, and the host country's Institut National de la Recherche Agronomique (INRA), Morocco. This major international development assistance program focused on improvement of the productive potential and human welfare in Morocco's semiarid, rainfed cereal production zone. The project dealt with (i) infrastructure development involving establishment of a dryland research center in Settat and a network of agricultural research substations; (ii) human resources capacity building, involving training junior national scientists at the graduate (M.S., Ph.D.) level, and INRA support staff in non-degree courses and training programs mainly at MIAC universities; and (iii) establishment of a viable research program related to dryland agriculture. The scientific mentoring and program development was done by a relatively small team of expatriate technical advisors, mainly from the United States, with project oversight by periodic external reviewers at discipline and overall program level. The DAARP had its strengths and weaknesses, its successes and failures. In this article, written by four scientists intimately involved with the project, an overview of the project is presented, highlighting its achievements and the lessons learned from its implementation. The article highlights the extent to which the DAARP is sustainable 12 years after completion, indicating that its shortcomings can be mainly attributed to a failure of the Moroccan government to fully live up to its commitments following completion of the project.

CYBER TRUST MODEL WITH APPLICATION TO THE ELECTRIC GRID

Our overall objective is to develop a multilayered model that can identify system vulnerabilities and detect anomalous system behavior. Once these model components have been developed, we could link the resulting multilayered SCADA systems (e.g., substation networks linked by the Internet) to determine system interactions, and then test, refine, and validate these models and data through increasingly sophisticated experiments to discover and record additional dependencies and system interactions. What do we want to trust? We want to have confidence that the system is available and reliable to deliver power to the utility's customers as their needs demand. Furthermore, we want a secure system that is not vulnerable to cyber attacks. Why might we have lack of trust in critical infrastructure systems? External threats to the electrical power infrastructure are increasing over internal threats. One reason is the increasing use of the Internet for connecting substation networks to other parts of the electric grid.

Local area supervisory protection system transformer taps

Abstract Connecting a transformer directly to the high voltage transmission line is a practical and relatively inexpensive way of providing service. The use of many circuit breakers is usually not justified, particularly at higher voltages. Motor operated air break switches (MOABs) instead of circuit breakers are used. To cope with the difficulty of switching arrangements, detection and clearing of transformer faults excluding the ground switch for MOABs operation, local area supervisory protection (LASP) system is proposed. LASP System collects current and voltage data from different locations on the power system through integrated equipment (IE) to relay equipment (RE). Asynchronous transfer mode (ATM) is a connection-oriented, packet-switched networking model between the LASP system and the equipment. Some attention is given to the architecture of a solution and some guidelines as to how this structure might be built to match with the next generation substation network architecture are also provided. The environment opens up new vistas for protection applications in the power systems.