ICT Architecture Impact on Wide Area Monitoring and Control Systems' Reliability
ABSTRACT 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 depen- dency 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 pos- sible 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.
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ABSTRACT: Traditional state estimators require longer scan time, leading to delayed, and inaccurate state estimation. Given the increased deployment trend of phasor measurement units (PMUs), it is expected that all-PMU state estimation will eventually replace traditional or mixed state estimators at the control centers of power utilities. Due to the repeated calibration of the voltage and current transformers at the measurement sites, and direct time-synchronized measurement of phasors, the estimated state by an all-PMU state estimator is not only accurate, but also available at a rapid rate, leading to the use of the system state for protection, stabilization, and even calibration of the measuring devices. However, due to high reliance on an advanced communication network infrastructure for the delivery of large amount of measurements in real-time, the cyber attack surface of the power system is increased. Deliberate cyber attacks or unintentional network failures can affect the state estimator leading to misoperations of the power system. In this paper, we study the cyber security impacts on the all-PMU state estimator, using a power system and data network co-simulation method. A linear state estimator for a model of the New England 39-bus system and the corresponding data network is built in a global event-driven co-simulation platform "GECO" which was developed and leveraged for our experimental setup. The co-simulation of PSLF (power system simulator) and NS-2 (network simulator) is run with injection of attacks on the network. The injected cyber attacks in the form of network failures or malicious data injection are simulated and their effects are observed. We also, observe the robustness of the all-PMU state estimator, when the number of affected measurements is below a threshold.IEEE SmartGridCom Symposium, Taiwan; 11/2012
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ABSTRACT: With the advent of the concept of smart-grid, the power system infrastructure is being equipped with high-bandwidth data communication and embedded computing infrastructure. The communication infrastructure has gained importance in the transmissions subsystems due to increasing use of the wide area measurement and monitoring using Phasor measurement units (PMUs). The amount of data collected by PMUs is large and they need to be transferred to regional and global data centers where real-time state estimation, and protection, stabilization decisions are made. As a result, having sufficient bandwidth in the communication infrastructure as well as proper delay characteristics will matter in the correct operation of these various wide area measurement system (WAMS) based control schemes. We have created a communication and power system co-simulation infrastructure called GECO which allows us to co-simulate power systems dynamics along with the communication network activities in a more realistic manner than past simulation environment. In this paper, we consider the effect of the appropriate network topology, bandwidth, delay etc. on two PMU based WAMS applications, namely All-PMU monitoring, and out-of-step protection. These experiments not only show the efficacy of the GECO framework in planning the smart grid communication infrastructure, it also provides case studies on how to go about using GECO in smart-grid design activities.Power and Energy Society General Meeting, 2012 IEEE; 01/2012
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ABSTRACT: A reliable and adequate communication network is crucial for smart grid applications. It is important to evaluate the performance of network infrastructure with respect to the diverse requirements imposed by various smart grid applications to ensure system reliability. Due to the complex dynamics involving communication and electrical systems, analytical study on smart grid faces challenges. As a result, comprehensive simulation platforms are needed for the study of interdependency between the heterogeneous systems. In this paper, we discuss the design of our smart grid co-simulation platform which combines power system simulator PSCAD/EMTDC with network simulator OPNET. In addition, we report a case study on Vehicle-to-Grid (V2G) voltage support application with respect to WiMAX / WiFi vehicle-to-infrastructure scenarios.Smart Grid Communications (SmartGridComm), 2013 IEEE International Conference on; 01/2013