Integrated transmission-and-distribution (T&D) modeling is a new and developing method for simulating power systems. Interest in integrated T&D modeling is driven by the changes taking place in power systems worldwide that are resulting in more decentralized power systems with increasingly high levels of distributed energy resources. Additionally, the increasing role of the hitherto passive energy consumer in the management and operation of power systems requires more capable and detailed integrated T&D modeling to understand the interactions between T&D systems. Although integrated T&D modeling has not yet found widespread commercial application, its potential for changing the decades-old power system modeling approaches has led to several research efforts in the last few years that tried to (i) develop algorithms and software for steady-state and dynamic modeling of power systems and (ii) demonstrate the advantages of this modeling approach compared with traditional, separated T&D system modeling. In this paper, we provide a review of integrated T&D modeling research efforts and the methods employed for steady-state and dynamic modeling of power systems. We also discuss our current research in integrated T&D modeling and the potential directions for future research. This paper should be useful for power systems researchers and industry members because it will provide them with a critical summary of current research efforts and the potential topics where research efforts are needed to further advance and demonstrate the utility of integrated T&D modeling.

This report evaluates the economic benefits, distribution system effects, and control system requirements associated with the deployment of a combustion turbine generator and a 6 MW / 8 MWh lithium-ion Tesla battery system deployed on Nantucket Island, MA.

The use of a Graph Trace Analysis (GTA)-based power flow for analyzing the voltage stability of integrated Transmission and Distribution (T&D) networks is discussed in the context of distributed Photovoltaic (PV) generation. The voltage stability of lines and the load carrying capability of buses is analyzed at various PV penetration levels. It is shown that as the PV generation levels increase, an increase in the steady state voltage stability of the system is observed. Moreover, within certain regions of stability margin changes, changes in voltage stability margins of transmission lines are shown to be linearly related to changes in the loading of the lines. Two case studies are presented, where one case study involves a model with eight voltage levels and 784,000 nodes. In one case study, a voltage-stability heat map is used to demonstrate the identification of weak lines and buses.

Predicting the power output of a Photovoltaic (PV) installation, whether small roof-top or utility scale, is important from resource planning perspective. For a home user, knowledge of solar power availability in the next 12 hours helps in optimal load scheduling. For a utility operator with a mix of power sources, this predicted PV output (along with a knowledge of consumer load) helps in controlling optimal mix of generation and enabling a reliable sustained power with better resource utilization. PV output estimation models for clear sky are mature and well researched, however, the effect of weather-related factors such as cloud cover, smog, fog etc. are difficult to model and include in the PV output calculations. The aim of this innovative study is to forecast the power a PV system may generate in the next 24 hours using the appropriate theoretical models. The estimated data is compared to the actual PV system readings installed at the test site. The paper presents the results in two stages, firstly theoretical predicted ground level irradiance is calculated without any attenuation factor and in second stage the irradiance is adjusted using the cloud attenuation model (C.I_GH) proposed in this paper. The theoretical dataset acquired shows a reasonable accuracy when compared to the subjected PV system installed at the test site.

The boundaries between power transmission and distribution systems are diminishing due to rapid growth of Distributed Energy Resources (DER's). Hence, in order to study the steady state and dynamic behavior of the modern grid, it is necessary to model and solve transmission and distribution networks concurrently with minimum assumptions. Here, two current approaches for this purpose, namely Integrated Transmission and Distribution (T&D) modeling and Co-Simulation, are compared. Key performance parameters considered include speed of solution, phase imbalance handling, robustness, and response to topology changes. Results and conclusions are drawn from analyzing several systems composed of IEEE standard Transmission and Distribution system models.