While it is widely recognized that weather impacts the power flow, historically weather information has only been implicitly included. This paper presents an approach for the direct inclusion of weather information in the power flow. Key issues addressed by the paper include the availability of weather information, the mapping of weather information to electric grid components, a flexible and extensible modeling approach for relating weather values to the power flow models, and the visualization of the weather impacts. The approach is demonstrated on several electric grids ranging in size from 7000 to 82,000 buses using weather data over several different years.

This paper summarizes a grid optimization (GO) competition effort in the United States to find the best solution strategies for up to interconnect-scale power system networks with around 32,000 buses. The optimization problem is a mixedinteger, non-convex non-linear problem, (MINLP) and includes discrete variables such as unit commitment and line switching, control settings (transformer taps and phase shifters with impedance correction tables), and bus shunts. The case study includes six actual industry grids as well as 16 realistic synthetic grids created by three different dataset teams. The winners are selected and ranked based on scoring criteria, which consider the solution quality (such as objective functions) within time limits. Nine winner teams are selected from 26 competitor teams. The results achieved by different teams are described and the performance of different algorithms on synthetic grids and actual industry grids are compared and analyzed.

Synthetic power systems that imitate functional and statistical characteristics of the actual grid have been developed to promote researchers' access to public system models. Developing time series to represent different operating conditions of these synthetic systems will expand the potential of synthetic power systems applications. This paper proposes a methodology to create synthetic time series of bus-level load using publicly available data. Comprehensive validation metrics are provided to assure that the quality of synthetic time series data is sufficiently realistic. This paper also includes an example application in which the methodology is used to construct load scenarios for a 10,000-bus synthetic case.

Situational awareness is imperative for reactive power management, particularly for interpreting the results of studies evaluating the impact of geomagnetic disturbances or high levels of renewable generation on the grid. This paper introduces a visualization technique, VAR Ready Reserves (VRRs), to provide a novel and useful tool to enhance the situational awareness of users performing and interpreting power system studies. This visualization technique can be adapted to demonstrate the dispatch, injection, and absorption capability of reactive power devices (such as generators, shunts, SVCs) in either a chart view (VRR charts) or with an integrated system view (VRR GDVs) to provide users with the awareness of reactive power capability and dispatch over the duration of a simulation or spatially. This paper reviews industry practices for reactive power management, summarizes existing visualization strategies, and demonstrates the newly-developed VRRs on a 2000-bus case study.

Phase Shifting Transformers (PST) are used to control or block certain flows of real power through phase angle regulation across the device. Its functionality is crucial to special situations such as eliminating loop flow through an area and balancing real power flow between parallel paths. Impedance correction tables are used to model that the impedance of phase shifting transformers often vary as a function of their phase angle shift. The focus of this paper is to consider the modeling errors if the impact of this changing impedance is ignored. The simulations are tested through different scenarios using a 37-bus test case and a 10,000-bus synthetic power grid. The results verify the important role of impedance correction factor to get more accurate and optimal power solutions.

This paper presents a framework for coupled infrastructure studies between the electric power transmission system and transportation networks. The proposed methodology evaluates the impact of electric vehicle (EV) charging demand on grid. operation and power generation, Key modeling and coupling considerations are presented for each network, Case studies for various EV charging schemes are presented on networks situated in Travis County, TX for illustration. System loading and generation dispatch provide examples of two of the many analyses enabled by this coupled infrastructure simulation framework.

As many power electronic converter interfaced technologies have recently been integrated into power systems, it has resulted in substantial computation demands and potential numerical instability issues in power system dynamics studies. Using a proper integration time step is key to solve these issues and multirate methods, which utilize a smaller time step to capture the system behavior associated with fast states and a larger time step for slow states, are an efficient way to represent current power system dynamics. This paper proposes a methodology to evaluate the system dynamic behaviors depending on different integration methods: a single rate method and a multirate method. These methods are compared with the results of rotor angle dynamic simulations using two different sizes of systems. Computational time and performance accuracy of the two methods are also assessed for the comparison.

The development of synthetic transmission networks has equipped the power system research community with public test cases that can be used and shared freely. As the synthetic electric grid power flow model only represents a one-time snapshot of the system, this paper proposes a methodology of developing scenarios that can reflect a wide spectrum of system operating conditions. The general process of determining load and generation levels, planning scheduled outages, and dispatching generators is discussed. Techniques that are commonly used to aid the convergence of power flow of scenario case are also provided.

In high voltage electric grids, phase shifting transformers (PSTs) are devices in which the phase shift across the device can be varied to control the flow of real power. A consequence of this phase variation is that PST’s series impedance often varies with the phase shift, sometimes substantially. In power system analysis applications this variation is often modeled using a piecewise-linear impedance correction table. This paper analyzes the influence of incorporating impedance correction tables on a power flow solution. The presented method is implemented in two different test systems. A two-bus test system shows various transformer correction tables can make different power flow solutions. A 37-bus test system demonstrates the influence of the impedance correction table on both normal operating condition and contingency scenarios. The results reveal that impedance correction tables have impacts on power flow solutions and may help alleviate the overloaded lines following a contingency.