Wide Area Protection System Research Articles

Measurement Platform for Latency Characterization of Wide Area Monitoring, Protection and Control Systems

Measurement Platform for Latency Characterization of Wide Area Monitoring, Protection and Control Systems

Distributed cyber-physical intrusion detection using stacking learning for wide-area protection system

Wide-area protection systems (WAPSs) heavy depends on communication technologies to operate, which leaves space for cyberattacks. A well-designed stealthy and coordinated cyberattacks can disrupt the seamless operation of WAPS by compromising measurement signals, control signals, or both. In this paper, we present a distributed cyber-physical intrusion detection system (DCPIDS) that utilizes the bilateral data from both the cyber side and the physical side to accurately detect cyberattacks on both measurement and control signals in WAPSs. DCPIDS consists of multiple slave agents (SAs) scattered in every area of the power system for regional-area intrusion detection and a master agent (MA) embedded in the system protection center for system status awareness. For the SAs, a hybrid-based intrusion detection method is utilized to conduct regional-area intrusion detection. The proposed method receives the bilateral data to simultaneously detect data integrity attacks on measurement and control signals using three classification models and performs the identification of single and coordinated attacks using a rule-based approach. Further, to train the classification models in the proposed method, a NewStacking-based model training algorithm is adopted. The proposed algorithm combines different selected classifiers that operate on two different feature subsets, which improves the detection accuracy of the models and extends the generalization ability with better robustness. Experimental results reveal that the proposed algorithm has better performance than existing machine learning algorithms and state-of-art works, the proposed method can identify single and coordinated attacks with high accuracy, and our DCPIDS satisfies the real-time requirements for practical online application.

Development and implementation of a MATLAB-based phasor data concentrator for synchrophasor applications

This work presents the development of MatPDC, an IEEE Std. C37.118.2-2011 compliant Phasor Data Concentrator (PDC) implemented in the Matlab environment. MatPDC enables the integration of wide-area monitoring, protection and control system synchrophasor data into the Matlab platform, offering real-time access to synchronized data streams from multiple Phasor Measurement Units (PMUs). The key features of MatPDC include real-time data access, data integrity verification, data aggregation and alignment, compliant data communication, and latency calculation. These features facilitate efficient processing and analysis of synchronized data, reducing complexity and improving latency between data sources and applications. The development of MatPDC addresses the need for accessing and analyzing real-time synchrophasor data within the Matlab environment, providing researchers and engineers with a powerful tool for power system analysis and experimentation. By developing the PDC and synchrophasor applications on the same platform, MatPDC reduces complexity and latency between data sources and applications. It offers real-time access to synchronized data streams, ensuring data integrity through verification mechanisms and aggregating the data into a unified dataset based on time tags. The implementation of MatPDC opens up opportunities for researchers to work with real-time synchrophasor data. It facilitates the development of advanced algorithms, real-time simulations, and the verification of control strategies. The integration and evaluation of MatPDC demonstrate its effectiveness and potential in power system analysis, providing researchers and engineers with a valuable tool for their research and development activities.

Assessing Hardware in the Loop Approaches for Wide-Area Monitoring Control and Protection Devices

Wide-area monitoring, protection, and control (WAMPAC) systems are expected to support the transmission system operators in maintaining stability and security of supply in the future power systems. The WAMPAC solutions heavily rely on deployment and use of phasor measurement units (PMU) and related communication technologies. Laboratory testing in a realistic environment utilizing hardware in the loop (HIL) approaches can be successfully used to evaluate WAMPAC functionalities algorithms and to accelerate proofs of concept. However, different implementations of the HIL testing can be adopted and their inherent characteristics affect both the accuracy of the results and the overall testing capabilities. The objective of this paper is to provide a comparative assessment of three HIL approaches for laboratory testing of WAMPAC systems and devices. These testing approaches have been implemented in a laboratory configuration and applied to characterize WAMPAC devices. Moreover, methodologies to quantify the error introduced by these testing approaches in static and dynamic conditions are presented and applied to this laboratory configuration.

Security of Wide-Area Monitoring, Protection, and Control (WAMPAC) Systems of the Smart Grid: A Survey on Challenges and Opportunities

The evolution of power generation systems, along with their related increase in complexity, led to the critical necessity of Wide-Area Monitoring, Protection, and Control (WAMPAC) systems in today’s smart grid. Recent developments in smart measurement devices coupled with data communication technologies allow for significant improvements in power systems’ reliability, efficiency, and security. These technological advancements make WAMPAC systems of significant practical interest. However, the geographically distributed nature of such systems increases the potential attack surface and the risk of critical vulnerabilities. Thus, it is of paramount importance to identify the related threats and vulnerabilities as well as the prominent solutions relevant to WAMPAC systems. Consequently, this paper aims to provide a comprehensive review of WAMPAC security aspects along with the state-of-the-art research initiatives addressing such aspects. Specifically, this paper provides critical taxonomies of the cyber-security scope of WAMPAC that guide the accompanying survey of the recent studies on the WAMPAC security domain. As such, this article aims to pave the way for prospective researchers to pursue further studies in areas that require in-depth investigation into the security, reliability, and efficiency of WAMPAC as the backbone of smart grids.

Wide area monitoring, protection, automation, and control systems for medium voltage networks

Distribution medium voltage networks have a branched structure, many power centers, longcable and overhead lines. This complicates the process of their automation, since significant capital costs for new equipment are required. New solutions based on modern technologies can help speed up this process and make it more efficient. The authors propose the use of synchronized phasor measurement technology for automating medium voltage networks. This paper considers approaches that describe the possibilities of implementing the WAMPAC principles in such networks, provides several examples where these principles apply.

Time Synchronization for Smart Grids Applications: Requirements and Uncertainty Issues

Smart grid implementation requires that multiple distributed systems are synchronized within and between substations. This is needed to coordinate the Intelligent Electronic Devices (IEDs) as well as to align in time the measurement data associated with the same event, but collected in different points of a broad geographical area. The time synchronization accuracy requirements in power systems are application-specific and are classified in the IEC Standard 61850-5:2013. Depending on such requirements, alternative solutions can be used. For instance, sub-microsecond time synchronization is essential for the implementation of Wide Area Monitoring, Protection, and Control (WAMPAC) systems. In fact, time synchronization directly and indirectly affects Phasor Measurement Units (PMUs) accuracy. The PMUs can measure the magnitude, the phase, the fundamental frequency and the Rate of Change of Frequency (ROCOF) of ac voltage and current waveforms at times synchronized to the Universal Coordinated Time (UTC). Among such quantities, the phase data are those most strongly affected by time synchronization. If time synchronization accuracy is within ±1 µs, its impact on synchrophasor phase measurement is in the order of a fraction of mrad, i.e., low enough to have a negligible impact on the state estimation uncertainty of most of transmission and distribution systems. However, the need to interpolate the missing phasor values when data from PMUs with a different reporting rate are collected and aligned in time may unexpectedly boost synchrophasor phase estimation uncertainty.

Application of IIA Method and Virtual Bus Theory for Backup Protection of a Zone Using PMU Data in a WAMPAC System

Many wide area monitoring, protection, and control (WAMPAC) systems are being deployed by grid operators to deal with critical operational conditions that may occur in power systems. Thanks to the real-time measurements provided by a set of distributed phasor measurement units (PMUs), different protection algorithms can be run in a central location. In this context, this article presents and validates a novel method that can be used as a backup protection for a selected area in a power system. It merges the integrated impedance angle (IIA) protection method with the theory of virtual buses in wide area electrical power systems. The backup protection works this way: once a fault is detected (pickup time), another delay (added to the pickup time) is defined in order to wait for the primary protection to act. If this does not happen, the algorithm generates its backup trip. The proposed method has been called the zone integrated impedance angle (Zone IIA). A real-time PMU laboratory has been used to test the proposed algorithm using a real-time digital simulator (RTDS). The algorithm has been programmed in a real-time automation controller (RTAC). It has been tested in two different simulated setups: first, a 400 kV transmission system, with and without the use of renewable energy sources (RES); second, a 150 kV submarine line between the Greece mainland and an island, which is currently the longest submarine alternating current connection in the world. The results obtained during the tests have yielded tripping times for area protection in the order of 48 ms, if no time delay is used between the fault detection and the trip order. According to the test results, the proposed method is stable, reliable, obedient, and secure, also with RES installed in the power system. Additionally, the method is selective, i.e., during the tests no trip was executed for external faults, no trip was executed in no-fault condition, and all the applied internal faults were detected and tripped correctly. Finally, the protection method is easy to implement. The method is also applicable to protection against short circuits in distribution systems. According to the trip times observed during the tests, it is clear that these algorithms are well suited to implement backup protections in transmission grids, even in scenarios with high penetration of renewable energies. Considering that backup trip times in transmission grids are usually set between 400 and 1000 ms, and that the actuation times obtained by the proposed algorithm are under 100 ms, the method is suitable for its use as a backup protection.

Wide area monitoring, protection, and control application in islanding detection for grid integrated distributed generation: A review

The assimilation of Distributed Generation (DG) into the electric power system (EPS) has become more attractive as the world is following a trend to reduce greenhouse gas emissions by introducing more renewable energy forms resulting in high penetration scenarios. This high penetration of DGs brings several challenges to the protection philosophy of the EPS which compromises its reliability, availability, and efficiency. Under high DG penetration scenarios, conventional islanding detection methods (Idms) fail to detect an island as the grid loses its inertia to leverage a significant frequency and voltage mismatch necessary for Idms to effectively detect an islanding event. This has given rise to the birth of Artificial Intelligent (AI) methods that are found to perform better in islanding detection. AI Idms are computationally intensive and require a lot of data to operate accurately. Because the computational burden of these methods requires fast computing hardware, the current trend of AI Idms are integrated with Wide Area Monitoring, Protection, and Control (WAMPAC) system. This paper aims at reviewing all these Idms and the WAMPAC’s system latency when hosting AI Idms which are currently the best in islanding detection. This is done to determine if the WAMPAC system latency plus Idms computational time meet the islanding detection time specified by the IEEE Standard 1547 framework.

Reliability Analyses of Wide-Area Protection System Considering Cyber-Physical System Constraints

Wide-area measurement, protection and control systems link the cyber power system with the physical power system to realize a cyber-physical power system (CPPS). This paper proposes a reliability modeling and assessment method for the wide-area protection system (WAPS). The proposed WAPS model takes into account the decision accuracy of protection algorithms with limited available data at the control center, and combines it with the tripping reliability of protection devices in corresponding substations to form the operation accuracy of WAPS. In particular, the directional comparison algorithm used in decision-making is functionally divided into three modules, namely the initiation module, the fault area positioning module, and the faulted element recognition module. The proposed reliability models are established based on the Permutation and Combination method under the assumption that the data acceptance rate of the control center is d. The sequential Monte-Carlo simulation is used to solve the proposed reliability indices. Finally, the WAPS reliability assessment is presented for the IEEE 14-bus system and the key influencing factors are identified and discussed.

A semi-centralized blockchain system with multi-chain for auditing communications of Wide Area Protection System

Wide Area Protection System (WAPS) undertakes the important task of maintaining system reliability and stability when the power system is subject to abnormal or predetermined unstable conditions. The existing WAPS adopts a centralized mechanism to record and audit communication messages, which faces the risk of excessive authority and tampering with communication records and audit logs, thus making it impossible to achieve true transparency and fairness. Due to the involvement of multiple parties and equipment maintained by different manufacturers in the communication of WAPS, there are difficulties in tracing the cause of the accident and determining the at-fault party following misoperations and miss trips. To address this issue, we propose a semi-centralized blockchain system with multi-chain for auditing communications of WAPS. We first propose a semi-centralized system architecture according to the system architecture and management requirements of WAPS. Then, we utilize the blockchain network as a self-recording channel to achieve tamper-proof and non-repudiation verification interaction. We also design a multi-chain structure and classification node mechanism to meet the communication auditing requirements of multiple WAPS. We have designed a new block structure that conforms to the communication protocol of WAPS. To reduce the storage burden caused by the ever-expanding blockchain ledger, we propose a deletable blockchain scheme while maintaining the integrity and security of blockchain. Analysis and experiments show that the proposed blockchain system can support the secure, transparent, tamper-proof and traceable communication recording and auditing of WAPS along with high performance.

Simultaneous Optimization of Optical Communication Link Placement and Partitioning of Wide-Area Protection System in Smart Grids

Based on modern sensors, communication networks and computing technologies, wide-area protection system (WAPS) can acquire electrical quantities to precisely locate faults in smart grids. In WAPS, the communication network is responsible for rapidly and reliably transmitting data between a regional master station and its slave stations. The real-time data transmission is heavily dependent on the communication link (CL) placement. In addition to the rational partitioning of WAPS, the CL placement should be chosen so as to ensure the good performance of WAPS. The aim of this study is to extend the traditional partitioning of WAPS to the simultaneous optimization problem of partitioning and optical CL placement. The simultaneous optimization problem is formalized so as to minimize the construction cost of WAPS. Besides the optical CL placement and partitioning, to ensure the reliable and real-time transmission of data, the link bandwidth and cost of each optical CL is also captured in the optimization problem. Finally, numerical simulations are carried out on the IEEE 39-bus, 57-bus and 118-bus standard testing cases. The simulation results illustrate that the optical CL scheme can be non-negligible and that it will significantly influence the partitioning of WAPS.

Cybersecurity of Wide Area Monitoring, Protection, and Control Systems for HVDC Applications

The flexibility provided by High Voltage Direct Current (HVDC) systems can be further extended by Wide Area Monitoring, Protection, and Control (WAMAPC) systems. WAMPAC systems enable many HVDC applications and, on the other hand, inevitably introduce cybersecurity concerns that need to be addressed. In this work, a security domain layer and decision framework is reported to detect and mitigate the impact of false data injection (FDI) attacks targeting HVDC stations. Specifically, a rule-based cyber-attack detection method is introduced and implemented on Raspberry Pi and tested on the real-time HVDC simulation facility on the real-time digital simulator (RTDS) platform at ABB U.S. Corporate Research Center.

Synchrophasor Sensors Assisted Novel Algorithm for Power System Protection Reinforcement and Health Monitoring

This paper proposes a synchrophasors assisted novel algorithm for power system protection from various disturbances and health monitoring under critical conditions, as well as reinforcing the protective system by supervising and guiding the relays. The proposed algorithm, as a widearea backup protection system, monitors the power system health using the generator rotor angle and the bus voltage phasors and thus detects a disturbance using the absolute value of generator rotor angle deviation (|Δδ gi |). The disturbance is classified into fault, stressed condition or unstable condition using Δδ gi . During the fault or the stressed condition, the disturbance associated bus (parent bus) is identified using Voltage Sensitive Coefficient (VSC) to supervise and guide the operation of appropriate Undervoltage/Overvoltage (UV/OV) relays. For achieving this, the proposed algorithm employs the data received at Phasor Data Concentrator (PDC) in Wide-Area Protection System (WAPS) from all Synchrophasor Measurement Units (SMUs). The performance of the algorithm is tested on the New England IEEE-39 bus system. The results evince that the proposed algorithm at WAPS detects and classifies the disturbance efficiently besides monitors the health accurately and reinforces the protection reliability.

Real‐time data‐assisted replay attack detection in wide‐area protection system

The cyber-attack surface in the power grid has widened with the deployment of the wide-area monitoring, protection, and control (WAMPAC) system. Replay attacks are one of the most challenging attacks to detect in a WAMPAC system. The authors aim to address the problem of identification and repercussions of continuous replay attacks on wide-area backup protection schemes. The continuous replay attacks introduce a permanent lag in the phasor measurement unit (PMU) data. The authors classify such attacks into small, medium, and wide-scale based on the number of compromised substations. Furthermore, the signature of a replay attack is derived using a one-step-ahead prediction of PMU data. The resulting forecast error distributions are subsequently analysed using the Kullback–Leibler divergence metric. Results using field PMU data show that this method successfully distinguishes replay attacks from normal system operation and faults in the system. Therefore, the proposed scheme can be used to detect and mitigate the effects of replay attacks on wide-area protection schemes.

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).

System Integrity Protection Scheme (SIPS) Development and an Optimal Bus-Splitting Scheme Supported by Phasor Measurement Units (PMUs)

System integrity protection schemes (SIPS) are schemes that can, under potentially hazardous conditions, prevent a complete blackout of endangered parts of an electrical power system (EPS). The main objective of SIPS is to monitor the state of the power transmission network in real time and to react in emergency cases. This paper explores the use of phasor measurement unit (PMU) technology for the development of SIPS as a part of wide-area monitoring, protection, and control (WAMPAC) systems. A new SIPS development method is described using the experience from the real-time operation. The developed optimal bus-splitting scheme identifies potential actions that can eliminate or reduce power system overloads and protect the integrity of the power system. An optimal bus-splitting scheme based on a DC power flow model and PMU measurements is given as an example and is explained and tested on an IEEE 14 bus test system. Conducted simulations indicate that the described SIPS methodology supported by the PMU measurements can mitigate potential overloads of the observed network part.

A Priority-Based Multistage PMU Installation Approach for Direct Observability of All Network Buses

The highly precise synchrophasor measurements obtained from the phasor measurement unit (PMU) are important for an effective implementation of a wide-area monitoring, protection, control, and self-healing (WAMPCAS) power system. The overall performance of the WAMPCAS power system can be improved if the PMUs are installed at all the buses in a transmission network. However, the multistage PMU installation is obligatory as PMU installation at all network buses is a matter of large-scale investment. Priority should be given to the important buses during the initial and intermediate stages to obtain relatively better observability. The optimal PMU installation (OPI) should be determined at the preliminary stage to measure the voltage phasors of all buses with the least number of PMUs. To evaluate the OPI problem, an improved binary shuffled frog leaping algorithm (IBSFLA) was proposed for the IEEE 118-bus test system. To enhance the overall performance of the IBSFLA and to obtain possible multiple optimal solutions (MOSs), an improved initialization and similarity-checking assessment were developed. A bus-observability maximization was mathematically modeled to select the best solution from MOSs, and the efficacy of the proposed algorithm was verified by comparing its performance with other algorithms.

A Hierarchical Self-Adaptive Data-Analytics Method for Real-Time Power System Short-Term Voltage Stability Assessment

As one of the most complex and largest dynamic industrial systems, a modern power grid envisages the wide-area measurement protection and control (WAMPAC) system as the grid sensing backbone to enhance security, reliability, and resiliency. However, based on the massive wide-area measurement data, how to realize real-time short-term voltage stability (STVS) assessment is an essential yet challenging problem. This paper proposes a hierarchical and self-adaptive data-analytics method for real-time STVS assessment covering both the voltage instability and the fault-induced delayed voltage recovery phenomenon. Based on a strategically designed ensemble-based randomized learning model, the STVS assessment is achieved sequentially and self-adaptively. Besides, the assessment accuracy and the earliness are simultaneously optimized through the multiobjective programming. The proposed method has been tested on a benchmark power system, and its exceptional assessment accuracy, speed, and comprehensiveness are demonstrated by comparing with existing methods.

Post-fault prediction of transient instabilities using stacked sparse autoencoder

Post-fault prediction of transient stability of power systems has a great impact on the performance of wide area monitoring, protection and control systems. Situational awareness capabilities of a power system are improved by fast detection of instabilities after severe fault occurrences. This allows sufficient time to take necessary corrective control actions. In this paper, a novel method based on stacked sparse autoencoder is proposed to predict the post-fault transient stability status of the power system directly after clearing the fault. A dataset is generated off-line to train a stacked sparse autoencoder, and then the trained stacked sparse autoencoder is used in an online application of predicting any transient instability. The stacked sparse autoencoder is fed by the inputs, which are specific points extracted from the fault-on voltage magnitude measurements collected from the phasor measurement units. The effectiveness of the proposed method is demonstrated and compared with the conventional approaches that adopt multilayer perceptrons or post-fault measurements as it is applied to the 127-bus WSCC test system and to the Turkish power system.