Power System Communication Network Research Articles

Controllability evaluation of complex networks in cyber–physical power systems via critical nodes and edges

Certain edge failures in cyber–physical power systems (CPPSs) can cause cascading failures in the power system. Protecting these critical edges and essential equipment in the supporting communication network can avoid these failures. Here, based on complex network controllability regarding kinetic equations and considering the actual operating conditions of CPPSs, we filter out a class of transmission lines and a class of nodes in the power system communication network of the power system that show a significant impact on network controllability. We further validate the results of the filtering by examining the resulting network robustness. Through simulations, we observe that the power edges and communication nodes screened based on network controllability have the most significant impacts on system controllability. It is therefore crucial to protect these edges and nodes to achieve more stable power grid operation and prevent cascading failures. Finally, we validate our results using a case study on a city in Henan Province, China. Our simulations demonstrate that the addition of a communication system can enhance the controllability of the power system.

Frequency Regulation From Distributed Energy Resource Using Cloud-Edge Collaborations Under Wireless Environments

The increasing integration of variable renewable energy increases the demand for a power system’s frequency regulation resources. The decreasing share of controllable power generators makes the frequency regulation resources insufficient. Simultaneously, distributed energy resources (DER) on the distribution network side, such as storage devices, electric vehicles, and controllable building energy systems, have excellent potential to provide frequency support. However, power system dispatchers cannot control these resources in the same manner as conventional power sources. These sources have power output uncertainties and cannot directly access power system communication networks. This paper proposes a cloud-edge collaboration and wireless communication coordination framework to facilitate DER frequency regulations. The cloud balances the power uncertainty of controllability in edges together with computing burden, wire, and wireless communication loads. Also, the edges adjust storage’s power outputs to achieve frequency regulations and covering PV power fluctuations. A numerical case study demonstrates the effectiveness of the proposed method. The solution holds 95.5% frequency regulation adjustable power capacity of theoretical maximum on average. Meanwhile, the computing costs reduce by 36.3%, and wire communication only operates in 0.35% of a day as a supplement (reduces by 99.65%).

Assessment of the robustness of cyber-physical systems using small-worldness of weighted complex networks

This paper extends the definition of Small-worldness to weighted complex networks and uses it to assess the robustness of Cyber-physical Critical Infrastructure Systems (CPCIS) and consequently to identify system critical components. System uncertain parameters – electric power system loading and communication network latency, are first incorporated in the model, and small-world property indices – Characteristic Path Length, Clustering Coefficient, and small-worldness are assessed in their dynamic (time-varying) forms to represent real-time uncertain criticalities, evaluated using probability distribution functions. The most critical physical and cyber system components are then identified, and their dependencies on physical and/or cyber system are identified. It was clearly demonstrated that the CPCIS components are mutually dependent on each other and that this dependency (represented by the drop of dynamic small-worldness in one system if a failure occurs in the other system) might vary from bus to bus. The proposed methodology is illustrated on a realistic interconnected 1326-bus transmission network and 88 bus star-connected ICT network, divided into 6 control zones.

Application of DR and co‐simulation approach for renewable integrated HEMS: a review

The evolvement of sustainable smart grid (SG) technology, advanced metering infrastructure, bidirectional communication and information infrastructure has revolutionised advancement in home energy management system (HEMS). The intelligent monitoring and control of renewable generation and distribution have their positive impact on the ease and convenience of the consumers to reduce overall energy consumption and to improve the comfort level. This study presents an overview of existing HEMS and their feasibilities. It also explores different controlling techniques and their functionalities that have been adopted to bring out future perspectives on the advancement of HEMS. The existing hardware implementations for HEMS along with communication protocols are discussed. Different demand response (DR) programmes and their compatibility are well-classified for HEMS, and also the range of application for HEMS has been discussed. Optimisation techniques that are used for different objectives of DR and HEMS are well-furnished in this study. The motivation, setbacks and their solutions for co-simulation approach along with the different power system simulators and communication network simulators and their compatibility for SG environment and HEMS are explored in the study.

Research on Security Problems and Defense Strategies of Power Communication Networks

The development direction of power systems is automation, networking and intelligence. The intranet and extranet dual network operation modes have been applied in the power system, but there are still many problems. Due to the continuous expansion of the power communication network, massive communication data is continuously generated in daily operation. At the same time, the means of attack on the power system communication network has evolved, seriously threatening the security of the power communication network. Therefore, it is necessary to further increase the research on the security and protection of power communication networks. This paper discusses the current status of China’s power communication network, analyzes the main factors affecting the security of power communication networks and the security problems of power communication networks. Finally, corresponding protective measures are given to provide reference for improving the security and stability of power communication networks.

Two Modes Power Optical Fiber Network Monitoring with Protective Optical Path and Fault Self-Recovery

The optical fiber communication network of city power system has the characteristics of dense network, complex laying environment, and the interruption of communication is high cost. Two modes optical fiber network monitoring solution with protective optical path and fault self-recovery is discussed to ensure the reliable work of the optical fiber network. For optical fiber line that lacks core resource, the monitoring mode with protective optical path and fault self-recovery is designed to monitor working core, and the problem of waste fiber core and interruption of working core can be solved. For optical line that plenty of core resource, the monitoring mode is designed to monitor non-working core. The monitoring mode switch method is proposed, and each optical fiber can select one mode independently to adapt different demands. An optical power prediction model is proposed based on an improved Elman neural network. As result, scientific maintenance plan can be made in terms of trend analysis of optical fiber line to reduce maintenance cost. Finally, using experimental core and real optical fiber line in power system, the testing result of the monitoring solution is analyzed to illustrate the effect of the solution.

Reliability analysis of service routing for a power system communication network based on MCS‐RBD

The Reliability Block Diagram (RBD) is widely used to calculate the reliability of power systems, while it can hardly distinguish the states of information transmission between normal and fault. To reflect the reliability level of the transmission route objectively, a Modified Cut Set of RBD (MCS‐RBD) is put forward. Traditional Traffic Routing Assignment Algorithms such as Open Shortest Path First (OSPF) and Optimized Link State Routing Protocol (OLSR) cannot balance the risk of excessive service concentration in the communication network of power systems. Hence, a Service Importance Balance‐Based Traffic‐Routing Assignment Algorithm (SIBTRA) is introduced to adjust the service distribution to avoid excessive concentration properly. In this study, important degrees of services are determined, respectively, whereby complete sets (CSs) and tie sets (TSs) of a communication network are built, which includes a source‐node station and a destination‐node station. Moreover, reliability of every node and path is calculated. Consequently, the system reliability of the optical transmission network is determined by all the elements described above. Meanwhile, the reason for using SIBTRA to balance the service distribution of the electric power communication can be assessed. Besides node reliability and path reliability, service‐routing reliability of communication networks before and after renovation is computed using MCS‐RBD and compared simultaneously, which validates the ability and feasibility of the MCS‐RBD positively. © 2018 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

Modeling Intelligent Control Switch IEC 61850 Based Substation Automation Communication

With the advent of the new information technologies, the power communication service object is continuously enhanced by the modernization level of the switches architecture designed in the substation automation environment. In the futuristic plan, the communication network not only provides a transmission line between devices, but also takes into account the reliability and efficiency of the power system communication network. Many protocols are used for the provision of faster and more robust communication among control centers, Remote Terminal Units (RTUs) and Intelligent Electronic Devices (IEDs). These protocols support the exchange of a wide range of possible common data that is organized by a DATA-SET, such as in synchronized circuit breaker switching, distance protection and overcurrent protection. However, these protocols do not give the expected performance with standard switches architectures due to the remarkable traffic in power system communication. To address this issue, this paper modelled a substation automation switch based on the packet forwarder technique based on Generic Object Oriented Substation Event (GOOSE) protocol with different architectures of substation automation switches based International Electrotechnical Commission (IEC) 61850 standard. Finally, the simulations results found that the architecture of the four-switch system showed a significant performance, as compared with other architectures.

Risk analysis and optimization for communication transmission link interruption in Smart Grid cyber-physical system

Since the communication network of the cyber-physical power system is responsible for communicating information, which guarantees the operation of the cyber-physical power system, researchers focus on the stability of the communication system. This article analyzes the risk of the communication transmission link interruption based on the network structure and characteristics of service transmission and proposes a path optimization method. First, we analyze the impact of link disruption on network structure and service, respectively, and quantify the impact as link interruption risk. According to the risk analysis, we propose an optimization method utilizing the Dijkstra’s algorithm and the genetic algorithm to reconfigure service paths, which aims to minimize time delay and realize the equilibrium of service distribution. Through a particular situation, we calculate the link interruption risk and use the optimization method to configure service path for affected service. The results show that the time delays of the optimized service paths are in the acceptable level as well as the balance index of the service distribution is decreased obviously. The simulation experiment reveals the operability of the risk analysis method and the effectiveness of the path optimization method, which provides a technical reference for risk analysis and service path configuration.

Co-simulation of Power System and Synchrophasor Communication Network on a Single Simulation Platform

Analysis of the impact of communication network infrastructure performance on critical power system applications that rely on wide area synchrophasor measurements can be realistically achieved only through co-simulation of the power system and the synchrophasor communication network. In this paper, a single simulation platform, an electromagnetic transient (EMT) simulation program - PSCAD/EMTDC, was used to implement the detailed models of the components in a wide area synchrophasor network. Using the developed components models, a simple wide area damping control application was co-simulated to demonstrate the impact of communication latency, packet losses, and bit flip errors on the controller performance. It was shown that with the aid of co-simulations, application specific issues can be diagnosed and appropriate solutions can be investigated.

A multi-level hierarchical communication network architecture for distributed generators

Power systems have been dramatically changing with cutting-edge information technologies. The new power system infrastructure has evolved and has been studied by many institutes and companies. Future power systems are bound up quietly with customer-side activities such as real-time pricing and distributed generators (DGs). To deploy those services on the power system, independent and hierarchical communication network architecture is proposed by information hiding and suppressing data exchange in this paper. The function of self-healing and resist attack will be easily implemented by this proposed network. This paper especially focuses on communication bandwidth and topology for power distribution areas as a backbone network for DGs.

Research on Electric Power Communication Optical Fiber Transmission Network Evaluation and Optimization Method

With the improvement of power industry modernization, electric power communication service object is no longer confined to the electric power dispatching, and the scope of services business also won the development, which requires the power system communication network is stable, reliable and efficient. The reliability of the power system optical fiber transmission network operation is an important guarantee of electric power system`s production safety and efficiency. In order to facilitate the planning and design of optical fiber transmission network management and maintenance, this paper proposed an optimization strategy based on the analysis and research of electric power communication optical fiber transmission network evaluation methods.

Coding embedded hybrid switching fabric applications in next generation power system backbone

With the advent of the new information technologies, the power communication service object is continuously improved by the modernization level of the electric power industry. The long term planning goal is not only to provide a transmission pipeline of power dispatching, but also a variety of service type, which requires a reliable and high efficiency power system communication network. Previous researches on the wide area protection propose a feasible solution on adaptive protection by using IP/SDH-based WAN. With the increasing capacity requirement, tradition IP/SDH device will be replaced gradually by the optical transport network. In this paper, we propose a novel hybrid switching fabric reconfigurable optical add-drop multiplexer/optical cross-connect (ROADM/OXC) by using electric coding embedded approach on the high speed backbone router. Also, the corresponding hybrid switching network coding (HSNC) scheme is propose to implement real-time cross-connect operation. HSNC schemes are integrated with MAWAPS of previous research and the results show that it is an efficient approach for various granularities switching structure. Performance of HSNC under different switching ratio and fiber core is presented and is also compared with traditional approach, and it is concluded to be a competitive approach that can be widely used in the next generation power grid backbone.

The Reliability Evaluation Method Study of Power System Communication Networks in Case of Ice Storm

This paper is divided into two cases to study the communication transmission equipment reliability in the state of the ice storm, according to the huge losses of power system communication caused by the ice storm. For the nodes or links which are not affected by the ice storm, we use the calculation with “the mean time between failures (MTBF)” and “the mean time to repair” (MTTR) to put forward the calculation methods; for the OPGW cable which influenced greater in ice storm, we use the fiber excess length and the elongation of fiber optic cable. It obtains all the paths of the network through improved adjacency matrix method, and then it uses binary decision diagram to obtain the overall reliability of the network. By testing the network nodes and links using “N-1” inspection, the key nodes and key links can be obtained. Finally, considering the importance degree of network transmission business, the reliability evaluation method of power system communication network based on the risk theory in the case of the ice storm has been put forward, and the example to verify that the method can provide the basis for the reliability assessment of the power system communication in the case of the ice storm has been given.

Optimal topological design of power communication networks using genetic algorithm

An electric power supply is the backbone of development in advanced as well as in developing economies. An integral part of ensuring a secure power supply system is a power communication system. Due to the high and sustained performance requirements of power communication systems, electric companies prefer to construct their own communication networks privately rather than relying solely on a public communication system. The focus of this paper is on the optimal topological design of a power communication network. Based on advanced optimization models in public communication networks, and taking into account the specific Quality of Service, as demanded by various applications, such as protection, SCADA, voice, etc., an optimization model (PC/ISO) has been developed. The PC/ISO requires tedious numerical processing. Hence, a Genetic Algorithm (GA) is proposed to solve the optimization problem. In order to demonstrate the application of the proposed model for a power system communication network design and in order to evaluate GA solver results, a case study on designing the optimal communication network topology of one of the Iranian Regional Electric Companies has been conducted. The results suggest that the PC/ISO model and its GA solver are entirely viable and offer a simple, accurate, and cost effective solution.