Barry Rawn

Carnegie Mellon University | CMU · Department of Electrical and Computer Engineering

Purpose This paper aims to provide insights into the environment needed for advancing a digitally enabled circular plastic economy in Africa. It explores important technical and social paradigms for the transition. Design/methodology/approach This study adopted an interpretivist paradigm, drawing on thematic analysis on qualitative data from an in...

Remote sensing can map actual irrigation areas using vegetation indices. Ground-truthing is critical for achieving maximum accuracy in crop acreage assessment over a large area. Machine learning practitioners are developing and validating techniques for generating inferences about infrastructure interventions' human and agricultural effects.The lim...

The paper analyzes the current state of plastic value chains in Africa and the potential of digital innovations adopted by African entrepreneurs to contributing to a circular plastic economy. We provide an overview of plastic waste trade to African countries and an assessment of existing digital solutions that can support the transition to a circul...

Increasing levels of complexity, due to growing volumes of renewable generation with an associated influx of power electronics, are placing increased demands on the reliable operation of modern power systems. Consequently, phasor measurement units (PMUs) are being rapidly deployed in order to further enhance situational awareness for power system o...

Second-use applications for batteries can play an important role in reducing the environmental impacts and life-cycle costs of electrochemical energy storage. The economic feasibility of re-using a battery pack is strongly influenced by the state-of-health (SOH) of its modules and cells after primary use. Thus, there is a strong incentive to optimi...

Extreme voltages at the system nodes are one of the primary causes for total and partial collapse of the Nigerian grid. In this paper, we develop a framework to re-dispatch the voltage set-points of committed generators in the grid to improve the voltage profile of the system nodes thus lowering the likelihood of a grid collapse. This framework is...

This chapter provides an overview of major transmission planning activities related to wind integration studies in the United States and Europe. Transmission planning for energy resources is different from planning for capacity resources. Those differences are explained and illustrated with examples from several regions of the United States and Eur...

Energy poverty, in particular, the lack of access to electricity, is a chronic impediment to sustainable development in sub-Saharan Africa, affecting over one billion people. Recently, electrification efforts have bifurcated into two pathways: grid extension/enhancement and off‑grid. Expanding and enhancing the existing national grid is the de fact...

This paper provides an overview and discussion of the ways in which the grid's Thévenin equivalent impedance (TEI) may be obtained in theory and practice. This parameter is valuable for a number of applications such as voltage stability monitoring and anti-islanding detection for distributed generation (DG). The theory behind the two most relevant...

This paper develops a long term transmission expansion optimization methodology taking the probabilistic nature of generation and demand, spatial aspects of transmission investments and different technologies into account. The developed methodology delivers a stepwise investment plan to achieve the optimal grid expansion for additional transmission...

This paper is concerned with the calculations of the phase current asymmetry on the power vhv overhead transmission line with two circuits. Presented algorithm allows taking into consideration the mutual inductive and capacitive couplings between the conductors. Their effect can be reduced with the help of the transmission line transposition. On th...

Following text is dealing with control possibilities during the moment of transition in to Island Operation of city of Pilsen in view of keeping the balance between generation and consumption. To achieve stable system we use number of control tools and one of them might be the use of DSM (Demand Side Management) as a supportive regulation tool. Cur...

This paper introduces a stepwise investment optimization methodology for transmission system expansion planning. The objective of the developed methodology is to determine transmission expansion plans to realize a desired interconnection capacity between multiple zones minimizing investment and operational costs. The methodology uses MILP optimizat...

This paper develops a long term transmission expansion optimization methodology taking the probabilistic nature of generation and demand, spatial aspects of transmission investments and different technologies into account. The developed methodology delivers a stepwise investment plan to achieve the optimal grid expansion for additional transmission...

The burden on conventional units to regulate the system frequency increases if they are replaced due to wind farms. This paper explores up to which time scales the rotating kinetic energy in wind turbines can smooth frequency variations and assist with the regulation task. To this end, a comparison is made between a standard wind turbine controller...

This study presents a market-based dynamic transmission planning framework for the construction of a meshed offshore voltage source converter-high voltage direct current (VSC-HVDC) grid. Such a grid is foreseen for integrating offshore wind and electricity trade functions among the North Sea countries. The proposed model seeks to maximise the socia...

Penetration levels of distributed wind power park modules (WPPMs) reach such high levels in parts of the world, for example, Germany, that reverse power flows (RPFs) from distribution to transmission level occur regularly in certain areas of the power system. This study compares the impact of normal and RPFs on the network fault response of WPPMs i...

This file includes a matpower case for the CWE grid. The grid data has been obtained from the public websites TSOs: RTE, Elia, TenneT, Transnet BW, Amprion and 50Hertz. The substation names are included. The grid impedances are the real impedances. The 220kV and 380 kV networks are provided in the datasets. ATTENTION: The data published by the TSO...

An algorithm to determine optimal transmission routes and to perform technology selection for transmission system expansion is developed and presented in this paper. The aim of the optimization is to minimize investment and installation costs of grid expansion, taking into account spatial properties. The optimization is performed by formulating pos...

There is significant interest in building HVDC transmission to carry out transnational power exchange and deliver cheaper electricity from renewable energy sources which are located far from the load centers. This paper presents a market-based approach to solve a long-term TEP for meshed VSC-HVDC grids that connect regional markets. This is in gene...

This paper presents a method to optimize equipment investments in multizonal transmission systems, considering spatial properties of the areas of focus. Together with a probabilistic technique for assessing nodal injection capability, the method in the paper completes the methodology of a long term transmission system planning tool. Transmission to...

High penetrations of photovoltaic (PV) systems in distribution grids have brought about new challenges such as reverse power flow and voltage rise. One of the proposed remedies for voltage rise is reactive power contribution by PV systems. Recent German Grid Codes (GGC) introduce an active power dependent (APD) standard characteristic curve, ${rm Q...

This paper evaluates, for a 2030 scenario, the impact on onshore power systems in terms of the variability of the power generated by 81 GW of offshore wind farms installed in the North Sea. Meso-scale reanalysis data are used as input for computing the hourly power production for offshore wind farms, and this total production is analyzed to identif...

During partly cloudy conditions, the power delivered by a photovoltaic array can easily fluctuate by three quarters of its rated power in 10 s. Fluctuations from photovoltaics of this size and on this time scale may necessitate adding an additional component to power system secondary and primary reserves to regulate frequency. This study quantifies...

This paper explores a control strategy for implementing damping of onshore power system oscillations through a voltage source converter based HVDC offshore grid. Time domain simulations are performed for a North Sea grid case study where the DC grid connects two asynchronous power systems as well as offshore wind power plants. An equivalent of the...

Wind turbines can, in principle, be operated to smooth wind power fluctuations by allowing wider variations in turbine speed and generator torque to store and release energy. This ability must be constrained by turbine speed and generator torque limits. To present, work in the literature is conceptual and does not indicate what extent of smoothing...

In a transmission system with HVDC lines or other power flow controlling devices, it is possible to control the active power flow in the lines and indirectly also in other parts of the system. The active control of the power flow through a grid can affect flow-based transmission cost allocation methods as they are based on the DC load flow model. T...

This paper provides an overview of major transmission planning activities related to wind integration studies in the United States and Europe. Transmission planning for energy resources is different from planning for capacity resources. Those differences are explained, and illustrated with examples from several regions of the United States and Euro...

The ability of wind power park modules to control their response to transmission network faults allows for specification of new control features directed at stabilising the power system response during and after disturbances. However, the `effectiveness' of these features in situations where wind power park modules are connected to `weak' systems n...

The transformation of the power system in terms of efficiency and sustainability will further lead to increasing converter-coupled generation and demand. This changes the system's characteristics and influences its stability. Despite these fundamental changes, the secure operation of the power system must be maintained at all times. DG and any conv...

Power systems with high wind penetration experience increased variability and uncertainty, such that determination of the required additional operating reserve is attracting a significant amount of attention and research. This paper presents methods used in recent wind integration analyses and operating practice, with key results that compare diffe...

The problem of determining invariance kernels for planar single-input nonlinear systems is considered. If K is a closed set, its invariance kernel is the largest subset of K with the property of being positively invariant for arbitrary measurable input signals. It is shown that the boundary of the invariance kernel is a concatenation of solutions o...

The amount of wind power in the world is quickly increasing. The background for this development is improved technology, decreased costs for the units, and increased concern regarding environmental problems of competing technologies such as fossil fuels. Some areas are starting to experience very high penetration levels of wind and there have been...

The power system design was mainly based on developing the supply side (supply follows the demand) and minor attention was given in controlling the demand side. During the effort to accommodate larger shares of renewable energy sources, while maintaining the power balance and ensuring the reliability of the power system, the implementation of deman...

Wind power plants show different behavior than conventional (synchronous) generators. As the traditional power systems mainly consisted of centralized generation by synchronous machines feeding passive loads, it was well-understood how the system reacted in normal operation as well as during disturbances. As wind power plants are foreseen to increa...

Solar radiation has a fluctuating nature, especially in oceanic climates where cloud-induced fluctuations are very common. The fluctuations and thus the power system reserve requirements can differ a lot on a daily and hourly basis. In this paper, local hourly classification criteria are defined based upon a spectral analysis of the wavelet transfo...

Europe currently holds the largest installed capacity of wind power plants of all continents. Over decades of development, significant adaptations have been implemented to integrate wind turbines into the electrical power system. Wind power research has been accelerated by the need to maintain grid performance and reliability in the face of the exp...

This paper presents an assessment of the kinetic energy reserve that could be made available by aggregating a distributed group of wind farms. The size of reserve available for a single turbine and the range of wind speeds where it can be assumed available is computed and compared with the kinetic energy delivered by synchronous generators during t...

The determination of additional operating reserves in power systems with high wind penetration is attracting a significant amount of attention and research. Wind integration analysis over the past several years has shown that the level of operating reserve that is induced by wind is not a constant function of the installed capacity. Observations an...

This paper introduces definitions and an analysis method for estimating how much kinetic energy can be made available for inertial response from a wind turbine over a year, and how much energy capture must be sacrificed to do so. The analysis is based on the static characteristics of wind turbines, Weibull distributions of wind speed, and standard...

This paper introduces a new control topology for converter-interfaced wind turbines. Through a singular perturbation decomposition of the system dynamics, a controller is designed that isolates wind-power fluctuations from the power grid. Specifically, the controller causes the closed-loop wind turbine to behave as a simple first-order power filter...

This paper presents research into the limits on controllable power output from wind energy conversion systems. The viewpoint of imposing delivered power as a control input is explored though the introduction of a novel control structure for a fully-rated converter interfaced wind turbine. A singular perturbations decomposition of the system dynamic...

Torque and power control laws for wind turbines that contribute to stabilizing grid frequency are now widely suggested in the literature. These contributions are made possible by exploiting wind turbine kinetic energy and are therefore constrained by turbine hub speed limits, converter current ratings, and turbine hub stability. This paper introduc...