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

Evaluation of Single Phase Smart PV Inverter Functions in Unbalanced Residential Distribution Systems

In the United States, smart PV inverters integrated with residential distribution systems are becoming a more common occurrence. With integration of smart PV inverters, power utilities are experiencing an increase of number of operations with regards to switched capacitor banks, voltage regulators and on load tap changers. These increases can lead to excess wear and tear on the devices causing power utilities to perform unwanted replacement and maintenance. However, smart PV inverters when controlled under specific functions can enable these inverters to provide reactive power and voltage control which in turn lowers the number of operations for switched capacitor banks, voltage regulators and on load tap changers. Furthermore, the standard basis is that when implementing Unbalanced Residential Distribution Systems into the grid, centralized control is a well-known choice, however, decentralized control provides a strong case for usage when using smart PV inverters in residential distribution systems. The objective of this thesis is to provide a better understanding of Unbalanced Residential Distribution Systems tied into the distribution side of the power grid when using control functions. Furthermore, better understand and prove the theory of using decentralize control for smart PV inverters in a residential distribution system. The future work will be analyzing the role of restoration practices and islanded mode with control algorithms that are used in grid connected mode. The specific areas below will be discussed in this thesi

太陽光発電が導入された配電系統における蓄電池の最適計画・制御手法に関する研究

早大学位記番号:新8188早稲田大

Sensitivity of hot-cathode ionization vacuum gages in several gases

Four hot-cathode ionization vacuum gages were calibrated in 12 gases. The relative sensitivities of these gages were compared to several gas properties. Ionization cross section was the physical property which correlated best with gage sensitivity. The effects of gage accelerating voltage and ionization-cross-section energy level were analyzed. Recommendations for predicting gage sensitivity according to gage type were made

Analysis and design of a 1 kW Class-GD ultrasonic generator

Word processed copy.Includes bibliographical references (leaves 66-70)