Application of demand response to improve voltage regulation with high DG penetration

The ability of a consumer friendly demand response based voltage control (DR-VC) program to improve the voltage regulation in a low voltage distribution network (LVDN) with high penetration of DG is investigated. The use of active and reactive power management to regulate the nodal voltage in a distribution network with simple incremental reduction algorithm, in conjunction with DR, is proposed as a solution for over voltage and undervoltage issues in the LVDN. The algorithm micromanages the load and generation in the network enabling the operator to utilize grid resources economically and efficiently while maintaining fairness between consumers with minimum inconvenience. The algorithm is tested on a representative. 74-load radial urban distribution network (Dublin, Ireland) using consumer load and DG generation profiles. The system is modelled and analysed using COM interface between OpenDSS and MATLAB. The DR is modelled through a mixed integer linear programming (MILP), implemented in CVX, such that consumer inconvenience is prioritized. The DR-VC algorithm is capable of regulating load and generation within normal operation limits during undervoltage and overvoltage scenarios

Dispersed storage and generation case studies

Three installations utilizing separate dispersed storage and generation (DSG) technologies were investigated. Each of the systems is described in costs and control. Selected institutional and environmental issues are discussed, including life cycle costs. No unresolved technical, environmental, or institutional problems were encountered in the installations. The wind and solar photovoltaic DSG were installed for test purposes, and appear to be presently uneconomical. However, a number of factors are decreasing the cost of DSG relative to conventional alternatives, and an increased DSG penetration level may be expected in the future

Optimization of energy-constrained resources in radial distribution networks with solar PV

The research objective of the proposed dissertation is to make best use of available distributed energy resources to meet dynamic market opportunities while accounting for AC physics of unbalanced distribution networks and the uncertainty of distributed solar photovoltaics (PV). With ever increasing levels of renewable generation, distribution system operations must shift from a mindset of static unidirectional power flows to dynamic, unpredictable bidirectional flows. To manage this variability, distributed energy resources (DERs; e.g.,solar PV inverters, inverter-based batteries, electric vehicles, water heaters, A/Cs) need to be coordinated for reliable and resilient operation. This introduces the challenge of coordinating such resources at scale and within confines of the existing distribution system. It also becomes important to develop efficient and accurate models of the distribution system to achieve desired operating objectives such as tracking a market reference, reduction in operation cost or voltage regulation. This work surveys, discusses the challenges and proposes solutions to the modeling and optimization of realistic distribution systems with significant penetration of renewables and controllable DERs, including energy storage. To contain this increase in system complexity as result of the large number of controllable DERs available, the distribution system has to be adapted from a passive Volt-Var focused operator to a more active manager of resources. To approach this challenge, in this work, we propose two main approaches. The first is a utility centric approach, where the utility controls the dispatch of flexible resources based on solving an optimization problem. This approach would require the utility to have all the network and resource data and also the control over customer devices. Another approach is a more aggregator centric approach, where an aggregator is an entity that represents an aggregation of many diverse DERs or a Virtual Battery (VB). In this approach, it is the role of the aggregator to dispatch DERs, whereas the utility provides certain bounds and limits (calculated offline), which the aggregator (which dispatches resources in real-time) must operate under. The benefits of such an approach lie in improved data-privacy and real-time dispatch. We present simulation results validating the proposed methods on various standard IEEE and realistic distribution feeders

NUCLEAR POWER AND ELECTRIC GRID RESILIENCE: CURRENT REALITIES AND FUTURE PROSPECTS

Life as we know it in modern society relies on the smooth functioning of the electric Grid – the Critical Infrastructure system that generates and delivers electricity to our homes, businesses, and factories. Virtually all other Critical Infrastructure systems depend on the Grid for the electricity they require to execute other essential societal functions such as telecommunications, water supply and waste water services, fuel delivery, etc. This study examines the concepts of Critical Infrastructure and electric Grid resilience, and the role nuclear power plants do and might play in enhancing U.S. Grid resilience. Grid resilience is defined as the system’s ability to minimize interruptions of electricity flow to customers given a specific load prioritization hierarchy. The question of whether current U.S. nuclear power plants are significant Grid resilience assets is examined in light of this definition. Despite their many virtues and their “fuel security,” the conclusion is reached that current U.S. nuclear power plants are not significant Grid resilience assets for scenarios involving major Grid disruptions. The concept of a “resilient nuclear power plant” or “rNPP” – a nuclear power plant that is intentionally designed, sited, interfaced, and operated in a manner to enhance Grid resilience – is presented. Two rNPP Key Attributes and Six rNPP Functional Requirements are defined. Several rNPP design features (system architectures and technologies) that could enable a plant to achieve the Six rNPP Functional Requirements are described. Four specific applications of rNPPs are proposed: (1) rNPPs as flexible electricity generation assets, (2) rNPPs as anchors of hybrid nuclear energy systems, (3) rNPPs as Grid Black Start Resources, and (4) rNPPs as anchors of Resilient Critical Infrastructure Islands. The last two applications are new concepts for enhancing U.S. strategic resilience. Finally, a few key unresolved issues are discussed and recommendations for future research are offered. Study results support the overall conclusion that successful development and deployment of rNPPs could significantly enhance U.S. Grid, Critical Infrastructure, and societal resilience, while transforming the value proposition of nuclear energy in the 21st century