Wide Area Monitoring And Control System Research Articles

Component Contribution to the Total Reliability of the WAMS Network

Nowadays, the control of power systems relies on wide-area monitoring and control system (WAMS), which continuously measures and registers state vector values and is synchronized by signals from the uniform time system. A significant part of this system is the local information network, whose reliability largely determines the proper functioning of WAMS. One can assess the said reliability by dividing it into components. These are hardware or technical reliability associated with failure (destruction) of transmission channel elements or the integrity of communication lines, traffic reliability determined by time loss or data distortion without failure of a transmission channel element, software reliability related to errors in the development of exchange execution programs, and resilience against an external deliberate impact on the transmitted information. This paper addresses the assessment of the first three reliability components of the information network, shows its total value, and estimates the contribution of each component. The last component (resistance to an external deliberate action) is described in a huge number of works, which is why it is not considered in this paper.

Design and Validation of a Wide Area Monitoring and Control System for Fast Frequency Response

This paper presents the design and validation of a Wide Area Monitoring and Control (WAMC) system for Fast Frequency Response (FFR) to address the challenges associated with reduced and non-uniformly distributed inertia in power systems. The WAMC system, designed for the power system in Great Britain, is termed “Enhanced Frequency Control Capability (EFCC).” It uses real time measurements from Phasor Measurement Units (PMUs) to monitor the system state in order to rapidly detect frequency disturbances and evaluate the magnitude of power imbalances. The impact of the disturbances on different parts of the network is considered to subsequently allocate the required response for different regions of the network, all within less than one second from the initiating event. The capabilities and characteristics of different resources (e.g., wind, energy storage, demand, etc.) are also evaluated and taken into account to achieve a suitable, optimized and coordinated response. Case studies using highly realistic hardware-in-the-loop setups are presented and these demonstrate that the proposed system is capable of detecting frequency events and deploying appropriate and coordinated responses in a timely fashion even with degraded communication conditions, thereby effectively enhancing the frequency control in future low-inertia systems and permitting higher penetrations of low-carbon and low-inertia energy sources.

Reliability components of the WAMS information network

Power system modes can be controlled by use of a wide-area monitoring and control system (WAMS). It is based on the phasor measurement units (PMUs), connected by an infor-mation network covering a significant territory. The functioning reliability of such a network deter-mines to a big extend the correct operation of the entire monitoring system. To assess its reliability, the one can be decomposed conveniently into four components: hardware or technical reliability, traffic reliability, software reliability, resistance to external negative impact on the transmitted in-formation, and to consider each m independently. In this paper, the main attention is paid to as-sessment of the reliability and availability of the first three components in the information network.

A Prediction Algorithm to Enhance Grid Resilience Toward Cyber Attacks in WAMCS Applications

Monitoring and control of electrical power grids are highly reliant on the accuracy of the digital measurements. These digital measurements reflect the precision of the installed sensors, which are vulnerable to the injection of unknown parameters in the form of device malfunction and cyberattacks. This may question the operational security and reliability of many cyberphysical infrastructure such as smart grid. To resolve this issue, a multisensor temporal prediction based wide-area control scheme is proposed in this paper. The feasibility of the designed scheme is verified in an advanced synchrophasor measurements based wide-area monitoring and control system (WAMCS). This WAMCS adopts a flexible ac transmission system device (the primary controller) for controlling the smart grid's voltage profile. The algorithm is validated in a real-time environment with an innovative software-in-the-loop testing setup. The performance of the proposed technique in the presence of false-data-injection attacks shows promising results.

Time-Delay Analysis of Wide-Area Voltage Control Considering Smart Grid Contingences in a Real-Time Environment

This paper addresses the time-delay effects of the wide-area monitoring and control systems (WAMCS) in smart power grids which may critically impact system stability. The main purpose is to conduct a detailed delay analysis of the WAMCS in case of grid contingences. This analysis is performed via an advanced WAMCS testbed where a flexible ac transmission system (FACTS) device is utilized and controlled via a wide-area controller (WAC). Phasor measurements units (PMUs) are adopted to collect the real-time measurements for the WAC. The testbed results from an interface of four main segments known as the WAC; the actual FACTS device, the local area controller, and the power grid system along with the PMUs are simulated via a real-time digital simulator. To mimic the real case scenario, both hardware-in-the-loop and software-in-the-loop schemes are adopted in the experimental testbed, considering time-delay effects. The results obtained clarify the effect of delay in WAMCS in case of smart grid contingences.

Design phasor data concentrator as adaptive delay buffer for wide-area damping control

Phasor Data Concentrators (PDCs) are employed to aggregate data frames from multiple Phasor Measurement Units (PMUs) with the same time-stamp into data packets. This function is an essential step in the utilization of PMU data in Wide-Area Monitoring and Control (WAMC) system. This is facilitated by assigning a fixed and heuristically decided wait time to the PDC buffer. The processed PMU data packets are sent to WAMC applications or similarly PDCs at higher hierarchies in the WAMC system when either a PDC buffer is full or its wait time has passed. In this paper, two methods to configure adaptive PDC wait time based on recent PMU traffic delay patterns are proposed. The purpose is to reduce the frequency of performing delay compensations in wide-area damping control system. With the adaptive PDC delay buffer in place, the wide-area damping controller only switches its gain once every five seconds, given the studied PMU traffic delay scenarios, instead of the current practice which requires the control gain to be adapted on a per PMU data frame basis, e.g., 50 or 60 times every second. The proposed methods offer a perspective to efficiently utilize the supporting Information and Communication Technology infrastructure with the purpose to simplify the design and implementation of wide-area damping control system.

Security Implications of Transport Layer Protocols in Power Grid Synchrophasor Data Communication

Wide-area monitoring and control (WAMC) systems based on synchrophasor data streams are becoming more and more significant to the operation of the smart power grid. Reliable and secure communication, and higher quality of service (very low latency, high availability, etc.) of data are crucial to the success of WAMC systems. However, the IEEE standard for synchrophasor data communication (IEEE Standard C37.118.2-2011) does not place any restrictions on the choice of transport layer protocols. In light of this, we examine the communication between synchrophasors [phasor measurement units (PMUs)] and phasor data concentrators to analyze potential security vulnerabilities present at the transport layer, and investigate the advantages and disadvantages of both the TCP and UDP protocols, respectively, with an emphasis on security issues. Demonstrations of attacks related to these security vulnerabilities are shown in lab environment and underlying mechanisms are analyzed to determine the capabilities attackers to succeed with them.

Design of wide‐area damping systems based on the capabilities of the supporting Information Communication Technology infrastructure

The dependence of the functionality of the wide-area monitoring and control (WAMC) systems on the capabilities of their underlying Information Communication Technology (ICT) infrastructure indicates that the parameterisation of the WAMC application algorithm should be coordinated with the design of the supporting ICT system. This study presents a systematic approach to design wide-area damping systems considering phasor measurement unit (PMU) communication delays and data frame losses. The proposed design method is applied to calibrate a wide-area damping system based on generalised predictive control (GPC) for demonstration purposes. In addition, a framework to guide the parameterisation of the GPC- based wide-area damping system is also provided. This research offers a better perspective to predict the capabilities of the underlying ICT infrastructure in the WAMC systems. Moreover, the proposed design method can be generalised to design delay-robust damping systems with compensation limits. Finally, it also offers an opportunity to associate the parameterisation of the damping system with the capabilities of its supporting ICT infrastructure and the reliability of the intended damping control function.

Modeling and Simulation of Wide-Area Communication for Centralized PMU-Based Applications

Phasor-based wide-area monitoring and control (WAMC) systems are becoming a reality with increased research, development, and deployments. Many potential control applications based on these systems are being proposed and researched. These applications are either local applications using data from one or a few phasor measurement units (PMUs) or centralized utilizing data from several PMUs. An aspect of these systems, which is less well researched, is the WAMC system's dependence on high-performance communication systems. This paper presents the results of research performed in order to determine the requirements of transmission system operators on the performance of WAMC systems in general as well as the characteristics of communication delays incurred in centralized systems that utilize multiple PMUs distributed over a large geographic area. This paper presents a summary of requirements from transmission system operators with regards to a specific set of applications and simulations of communication networks with a special focus on centralized applications. The results of the simulations indicate that the configuration of central nodes in centralized WAMC systems needs to be optimized based on the intended WAMC application.

A Synchrophasor Assisted Frequency and Voltage Stability Based Load Shedding Scheme for Self-Healing of Power System

This paper presents a new scheme for load curtailment in the power system required for its self-healing under critical contingencies, which may pose a threat to frequency as well as the voltage stability of the system. The load shedding requirement in the system has been calculated based on the computed disturbance power as well as the voltage stability condition of the system, with the aid of real-time data, assumed to be available from the synchrophasor based wide area monitoring and control system (WAMCS). This scheme assesses voltage stability based on a dynamic voltage stability criterion, formulated using a Voltage Stability Risk Index (VSRI). Suitable locations for the load curtailments have been chosen according to the VSRI, calculated at each load bus. Performance of the proposed scheme has been tested on New England 39-bus system and a practical 246-bus Indian system. The results are compared with a conventional under frequency load shedding scheme and an adaptive load shedding scheme.

ICT Architecture Impact on Wide Area Monitoring and Control Systems' Reliability

Timely and accurate data with high resolutions holds great promise for more responsible and advanced power grid operations. The research has been focusing on design of monitoring and control scheme given the assumptions that the supporting information and communication technology (ICT) systems are capable of providing data and perform control with sufficient quality. A relatively less addressed aspect is the dependency of wide-area monitoring and control (WAMC) systems on their supporting ICT architecture which is usually a compromise between various concerns, such as data quality, interoperability, or security. Without an appropriate ICT architecture design, the projected WAMC system functionalities run the risk of being jeopardized. This paper begins with a presentation about possible delays brought by complex data-transfer and processing processes. Analytical experiments are conducted with purposes to quantify the maximum delay and input signal's sensitivity toward delay on a typical WAMC application where the control of static var compensation (SVC) is coordinated with generator excitations using phasor measurements. Given the characteristics of this particular control scheme, two possible ICT architectures that provide data with different qualities are compared concerning the reliability of this WAMC application. This paper concludes by proposing a generic ICT architecture, enabling efficient WAMC systems implementation in terms of data quality.