Real-Time Local Volt/VAR Control Under External Disturbances with High PV Penetration

Volt/var control (VVC) of smart PV inverter is becoming one of the most popular solutions to address the voltage challenges associated with high PV penetration. This work focuses on the local droop VVC recommended by the grid integration standards IEEE1547, rule21 and addresses their major challenges i.e. appropriate parameters selection under changing conditions, and the control being vulnerable to instability (or voltage oscillations) and significant steady state error (SSE). This is achieved by proposing a two-layer local real-time adaptive VVC that has two major features i.e. a) it is able to ensure both low SSE and control stability simultaneously without compromising either, and b) it dynamically adapts its parameters to ensure good performance in a wide range of external disturbances such as sudden cloud cover, cloud intermittency, and substation voltage changes. A theoretical analysis and convergence proof of the proposed control is also discussed. The proposed control is implementation friendly as it fits well within the integration standard framework and depends only on the local bus information. The performance is compared with the existing droop VVC methods in several scenarios on a large unbalanced 3-phase feeder with detailed secondary side modeling.Comment: IEEE Transactions on Smart Grid, 201

Power quality analysis for renewable power generation in household

Power quality is becoming essential part of Power Industry. The introduction of smarter and more sensitive equipment at both grid and residential level has created performance issues that need investigation. The cost of the power losses is rising due to power quality problems. The other significant factor that is proving vital is the customer dissatisfaction. The introduction of Renewable Energy (RE) into modern grids has also created Power Quality (PQ) problems. A study is required to narrow down the factors that can cause these PQ issues. The power companies are buying electricity back from the consumer produced by these RE sources. The power produced by RE sources coming into the electrical grid needs to be monitored. The research will focus on the factors that impact PQ especially the Total Harmonic Distortion in a electrical grid powered by renewable sources. The factors impacting power quality will be studied in detail by using an simulation approach aided by an experimental set up. The simulation approach will be used to test the hypothesis that total harmonic distortion increases by changing the nature and size of the load in the electrical system. The load type used for the research will be linear and nonlinear loads. The simulation will use single and three phase electrical system. The simulation results will be analysed and discussed. The experimental setup will be used to verify the simulation result. The experiment will be conducted on different set of load to observe the impact on the total harmonic distortion in particular. The experimental result will be collected over period of time enabling the researcher to study in detail the impact of weather, temperature, and inclination of solar panels. These factors will impact the research result. The collected data will be presented for discussion

Power quality analysis for renewable power generation in household

Power quality is becoming essential part of Power Industry. The introduction of smarter and more sensitive equipment at both grid and residential level has created performance issues that need investigation. The cost of the power losses is rising due to power quality problems. The other significant factor that is proving vital is the customer dissatisfaction. The introduction of Renewable Energy (RE) into modern grids has also created Power Quality (PQ) problems. A study is required to narrow down the factors that can cause these PQ issues. The power companies are buying electricity back from the consumer produced by these RE sources. The power produced by RE sources coming into the electrical grid needs to be monitored. The research will focus on the factors that impact PQ especially the Total Harmonic Distortion in a electrical grid powered by renewable sources. The factors impacting power quality will be studied in detail by using an simulation approach aided by an experimental set up. The simulation approach will be used to test the hypothesis that total harmonic distortion increases by changing the nature and size of the load in the electrical system. The load type used for the research will be linear and nonlinear loads. The simulation will use single and three phase electrical system. The simulation results will be analysed and discussed. The experimental setup will be used to verify the simulation result. The experiment will be conducted on different set of load to observe the impact on the total harmonic distortion in particular. The experimental result will be collected over period of time enabling the researcher to study in detail the impact of weather, temperature, and inclination of solar panels. These factors will impact the research result. The collected data will be presented for discussion

Doctor of Philosophy

dissertationThree major catastrophic failures in photovoltaic (PV) arrays are ground-faults, line-to-line faults, and arc faults. Although the number of such failures is few, recent fire events on April 5, 2009, in Bakersfield, California, and April 16, 2011, in Mount Holly, North Carolina suggest the need for improvements in present fault detection and mitigation techniques, as well as amendments to existing codes and standards to avoid such accidents. A fault prediction and detection technique for PV arrays based on spread spectrum time domain reflectometry (SSTDR) has been proposed and was successfully implemented. Unlike other conventional techniques, SSTDR does not depend on the amplitude of the fault-current. Therefore, SSTDR can be used in the absence of solar irradiation as well. However, wide variation in impedance throughout different materials and interconnections makes fault locating more challenging than prediction/detection of faults. Another application of SSTDR in PV systems is the measurement of characteristic impedance of power components for condition monitoring purposes. Any characteristic variations in one component will simultaneously alter the operating conditions of other components in a closed-loop system, resulting in a shift in overall reliability profile. This interdependence makes the reliability of a converter a complex function of time and operating conditions. Details of this failure mode, mechanism, and effect analysis (FMMEA) have been developed. By knowing the present state of health and the remaining useful life (RUL) of a power converter, it is possible to reduce the maintenance cost for expensive high-power converters by facilitating a reliability centered maintenance (RCM) scheme. This research is a step forward toward power converter reliability analysis since the cumulative effect of multiple degraded components has been considered here for the first time in order to estimate reliability of a power converter

Advanced Signal Processing Techniques Applied to Power Systems Control and Analysis

The work published in this book is related to the application of advanced signal processing in smart grids, including power quality, data management, stability and economic management in presence of renewable energy sources, energy storage systems, and electric vehicles. The distinct architecture of smart grids has prompted investigations into the use of advanced algorithms combined with signal processing methods to provide optimal results. The presented applications are focused on data management with cloud computing, power quality assessment, photovoltaic power plant control, and electrical vehicle charge stations, all supported by modern AI-based optimization methods

Analysis and Mitigation of Power Quality Issues in Distributed Generation Systems Using Custom Power Devices

This paper discusses the power quality issues for distributed generation systems based on renewable energy sources, such as solar and wind energy. A thorough discussion about the power quality issues is conducted here. This paper starts with the power quality issues, followed by discussions of basic standards. A comprehensive study of power quality in power systems, including the systems with dc and renewable sources is done in this paper. Power quality monitoring techniques and possible solutions of the power quality issues for the power systems are elaborately studied. Then, we analyze the methods of mitigation of these problems using custom power devices, such as D-STATCOM, UPQC, UPS, TVSS, DVR, etc., for micro grid systems. For renewable energy systems, STATCOM can be a potential choice due to its several advantages, whereas spinning reserve can enhance the power quality in traditional systems. At Last, we study the power quality in dc systems. Simpler arrangement and higher reliability are two main advantages of the dc systems though it faces other power quality issues, such as instability and poor detection of faults