Jeffrey E. Dagle

Autonomous demand response for frequency regulation on a large-scale model of an interconnected grid

This research examines the use of autonomous demand response to provide primary frequency control in an interconnected grid. The work builds on previous studies in several key areas: it uses a large realistic model; it establishes a set of metrics which can be used to assess the effectiveness of autonomous demand response; and it independently adjusts various parameters associated with using autonomous demand response to assess effectiveness and to examine possible threats or vulnerabilities associated with the technology. More than 6,000 simulations of the power system model were conducted during the course of the study. The studies demonstrated that very few conditions associated with autonomous demand response have the potential to degrade reliability, and that the marginal benefit attributable to autonomous demand response is quantifiable and can be used to determine the value of the technology, as compared to traditional means, for providing primary frequency control.

A low-alpha nuclear electric propulsion system for lunar and Mars missions

The advantages of using electric propulsion for propulsion are well‐known in the aerospace community. The high specific impulse and, therefore, lower propellant requirements make it a very attractive propulsion option for the Space Exploration Initiative (SEI). Recent studies have shown that nuclear electric propulsion (NEP) is not only attractive for the transport of cargo but that fast piloted missions to Mars are possible as well, with alphas on the order of 7.5 kg/kW. An advanced NEP system with a pecific power (alpha) of 2.5 kg/kW or less would significantly enhance the manned mission option of NEP by reducing the trip time even further. This paper describes an advanced system that combines the PEGASUS Drive with systems of the Rotating Multimegawatt Boiling Liquid Metal (RMBLR) power system that was developed as part of the DOE multimegawatt program and just recently declassified. In its original configuration, the PEGASUS Drive was a 10‐MWe propulsion system. The RMBLR was a 20‐MW electric power sy...

Modeling of protection in dynamic simulation using generic relay models and settings

This paper shows how generic protection relay models available in planning tools can be augmented with settings that are based on NERC standards or best engineering practice. Selected generic relay models in Siemens PSS®E have been used in dynamic simulations in the proposed approach. Undervoltage, overvoltage, underfrequency, and overfrequency relays have been modeled for each generating unit. Distance-relay protection was modeled for transmission system protection. Two types of load-shedding schemes were modeled: underfrequency (frequency-responsive non-firm load shedding) and underfrequency and undervoltage firm load shedding. Several case studies are given to show the impact of protection devices on dynamic simulations. This is useful for simulating cascading outages.

Reliability comparison of various nuclear propulsion configurations for Mars mission

Currently, trade‐offs are being made among the various propulsion systems being considered for the Space Exploration Initiative (SEI) missions. It is necessary to investigate the reliability aspects as well as the efficiency, mass savings and experience characteristics of the various configurations. Reliability is a very important factor for the SEI missions because of the long duration and because problems will be fixed onboard. The propulsion options that were reviewed consist of nuclear thermal propulsion (NTP), nuclear electric propulsion (NEP) and various configurations of each system. There were four configurations developed for comparison with the NTP as baselined in the Synthesis (1991): 1) NEP, 2) hybrid NEP/NTP, 3) hybrid with power beaming, and 4) NTP upper stage on the heavy lift launch vehicle (HLLV). The comparisons were based more or less on a qualitative review of complexity, stress levels and operations for each of the four configurations. Each configuration included a pressurized NEP and...