Verifying the power grid requires checking if the voltage drops on all the nodes do not exceed the threshold. We aim to correct an RC model of the grid when some voltage drops violate the threshold condition, by making minor changes to the original design. We first propose an accurate approach to correct the grid which turns out to be too slow. We therefore propose another approach, more suitable for large grids and which can be summarized as follows. The voltage drop is estimated as a function of the metal widths on the grid. A non-linear optimization problem is then formulated and the required metal line width changes that reduce the voltage drops by a sufficient amount are determined. There is a tradeoff between accuracy and speed of the algorithm. However the results show that the gain in speed achieved by the second method, outweighs greatly the loss in accuracy.

Verifying the power grid requires checking if the voltage drops on all the nodes do not exceed the threshold. We aim to correct an RC model of the grid when some voltage drops violate the threshold condition, by making minor changes to the original design. We first propose an accurate approach to correct the grid which turns out to be too slow. We therefore propose another approach, more suitable for large grids and which can be summarized as follows. The voltage drop is estimated as a function of the metal widths on the grid. A non-linear optimization problem is then formulated and the required metal line width changes that reduce the voltage drops by a sufficient amount are determined. There is a tradeoff between accuracy and speed of the algorithm. However the results show that the gain in speed achieved by the second method, outweighs greatly the loss in accuracy.

"The fast pace of global urbanization is drastically changing the population distributions over the world, which leads to significant changes in geographical population densities. Such changes in turn alter the underlying geographical power demand over time, and drive power substations to become over-supplied (demand ≪ capacity) or under-supplied (demand ≈ capacity). In this work, we make the first attempt to investigate the problem of power substation/user assignment by analyzing large scale power grid data. We develop a Scalable Power User Assignment (SPUA) framework, that takes large-scale spatial power user/substation distribution data and temporal user power consumption data as input, and assigns users to substations, in a manner that minimizes the maximum substation utilization among all substations. To evaluate the performance of SPUA framework, we conduct evaluations on real power consumption data and user/substation location data collected from Xinjiang Province in China for 35 days in 2015. The evaluation results demonstrate that our SPUA framework can achieve a 20%–65% reduction on the maximum substation utilization, and 2 to 3.7 times reduction on total transmission loss over other baseline methods."

Nearly every aspect of modern life today, from businesses, transportation, and healthcare, depends on the power grid operating safely and reliably. While the recent push for a “Smart Grid” has shown promise for increased efficiency, security has often been an afterthought, leaving this critical infrastructure vulnerable to a variety of cyber attacks. For instance, devices crucial to the safe operation of the power grid are left in remote substations with their configuration interfaces completely open, providing a vector for outsiders as well as insiders to launch an attack. This paper develops the framework for an overlay network of gateway devices that provide authenticated access control and security monitoring for these vulnerable interfaces. We develop a working prototype of such a device and simulate the performance of deployment throughout a substation. Our results suggest that such a system can be deployed with negligible impact on normal operations, while providing important security mechanisms. By doing so, we demonstrate that our proposal is a practical and efficient solution for retro-fitting security onto crucial power system devices.

Verification of the on-die power grid is a key step in the design of complex high performance integrated circuits. For the very large grids in modern designs, incremental verification is highly desirable, because it allows one to skip the verification of a certain section of the grid (internal nodes) and instead, verify only the rest of the grid (external nodes). The focus of this work is to develop efficient techniques for incremental verification in the context of vectorless constraints-based grid verification, under dynamic conditions. The traditional difficulty is that the dynamic case requires iterative analysis of both the internal and the external sections. A solution in the transient case is provided through two key contributions: 1) a bound on the internal nodes’ voltages is developed that eliminates the need for iterative analysis, and 2) a multi-port Norton approach is used to construct a reduced macromodel for the internal section.

Verification of the on-die power grid is a key step in the design of complex high performance integrated circuits. For the very large grids in modern designs, incremental verification is highly desirable, because it allows one to skip the verification of a certain section of the grid (internal nodes) and instead, verify only the rest of the grid (external nodes). The focus of this work is to develop efficient techniques for incremental verification in the context of vectorless constraints-based grid verification, under dynamic conditions. The traditional difficulty is that the dynamic case requires iterative analysis of both the internal and the external sections. A solution in the transient case is provided through two key contributions: 1) a bound on the internal nodes’ voltages is developed that eliminates the need for iterative analysis, and 2) a multi-port Norton approach is used to construct a reduced macromodel for the internal section.

The development of new concepts and methods for improving the efficiency of power networks needs performance evaluation with realistic grid topology. However, much of the realistic grid data needed by researchers cannot be shared publicly due to the security and privacy challenges. With this in mind, power researchers studied statistical properties of power grids and introduced synthetic power grid topology as appropriate methodology to provide enough realistic power grid case studies. If the synthetic networks are truly representative and if the concepts or methods test well in this environment they would test well on any instance of such a network as the IEEE model systems or other existing grid models. In the past, power researchers proposed a synthetic grid model, called RT-nested-smallworld, based on the findings from a comprehensive study of the topology properties of a number of realistic grids. This model can be used to produce a sufficiently large number of power grid test cases with scalable network size featuring the same kind of small-world topology and electrical characteristics found in realistic grids. However, in the proposed RT-nested-smallworld model the approaches to address some electrical and topological settings such as (1) bus types assignment, (2) generation and load settings, and (3) transmission line capacity assignments, are not sufficient enough to apply to realistic simulations. In fact, such drawbacks may possibly cause deviation in the grid settings therefore give misleading results in the following evaluation and analysis. To address this challenges, the first part of this thesis proposes a statistical methodology to solve the bus type assignment problem. This method includes a novel measure, called the Bus Type Entropy, the derivation of scaling property, and the optimized search algorithm. The second part of this work includes a comprehensive study on generation/Load settings based on both topology metrics and electrical characteristics. In this section a set of approaches has been developed to generate a statistically correct random set of generation capacities and assign them to the generation buses in a grid. Then we determine the generation dispatch of each generation unit according to its capacity and the dispatch ratio statistics, which we collected and derived from a number of realistic grid test cases. The proposed approaches is readily applied to determining the load settings in a synthetic grid model and to studying the statistics of the flow distribution and to estimating the transmission constraint settings. Considering the results from the first two sections, the third part of this thesis will expand earlier works on the RT-nested-smallworld model and develop a new methodology to appropriately characterize the line capacity assignment and improve the synthetic power grid modeling.

We consider the impact that various shocks and stresses have on the reliability of networks with radial topology, such as an electrical power grid. We incorporate the effects of aging, geographical risk, and local dependence between components into a model of overall system reliability. We also simulate how the system fares under extreme weather events, such as hurricanes. Our model gives a flexible and general understanding of how outside forces affect network reliability and can be adapted to a range of specific uses. We run a simulation using this model which yields realistic results.

Renewable power sources with a relatively uneven or constant DC power production require synchronization methods to work with the current utility power grid. The solution to this synchronization problem has been solved with semiconductor based converters and advanced switching algorithms. To enable switching algorithms that work well with the grids amplitude, phase-shift and frequency, the current waveform has to be measured and estimated.    There are many sources of noise that will add distortion of the current waveform, making its appearance less similar to the grids. The distorted measurement affects the accuracy of the converters negatively. Therefore, using a filter algorithm to attenuate the grid noise is required.  This project uses a Kalman filter with the aim to decrease the noise and estimate the current phase shift for a three phase power-grid.  To achieve reliable and fast calculation, implementing the Kalman filter within a FPGA were done.The project contains results from both simulated MATLAB data and the FPGAs real time data. The method was able to estimate the grid within a few Hz frequency deviation and enable some noise reduction. For larger degree of harmonic distortion during steady state operation, the Kalman filter could remove more of the harmonic distortion. Limits and differences with MATLAB are discussed for the FPGA implemented Kalman filter.

Electromigration in metal lines has re-emerged as a significant concern in modern VLSI circuits. The higher levels of temperature and the large number of EM checking strategies, have led to a situation where trying to guarantee EM reliability often leads to conservative designs that may not meet the area or performance specs. Due to their mostly-unidirectional currents, the problem is most significant in power grids. Thus, this work is aimed at reducing the pessimism in EM prediction. There are two sources for the pessimism: the use of the series model for EM checking, and the pessimistic assumptions about chip workload. Therefore, we propose an EM checking framework that allows users to specify conditions-of-use type constraints to capture realistic chip workload, and which includes the use of a novel mesh model for EM prediction in the grid, instead of the traditional series model.