This paper proposes a frequency control strategy for voltage source converter based multi-terminal HVDC systems (VSC-MTDC) to facilitate the exchange of primary frequency reserves among asynchronous AC systems, thus providing frequency support from each AC system to the others. The proposed frequency control utilizes a reference signal calculated from global measurements which reflects the overall frequency dynamics of all connected asynchronous AC systems. The proposed control outperforms the traditional frequency droop scheme by reducing impact on the DC voltage profile and improving frequency nadir. The performance of the designed frequency control with different DC voltage droop controls is evaluated. The adaptation of the proposed frequency control for converter outages is analyzed. The robustness of the proposed control to communication latency and the sensitivity of frequency support to power limits are also investigated. The VSCMTDC model and the proposed control are implemented in the commercial grade software PSS/E and thus is suitable to study large-scale realistic systems and can be incorporated into the power system planning process at utilities and ISOs. The effectiveness of the proposed control is illustrated on a developed AC-MTDC test system and also on a large-scale realistic model combining the North American Western Interconnection (WI) and Eastern Interconnection (EI) with continental HVDC interconnections.

Due to the insignificant share of inverter-based Renewable Energy Resources (RER) as well as the uncertainty concerning their integration impacts, the capability of RERs to regulate voltage or frequency has not been widely used. However, inverter-based voltage/frequency regulation is of interest due to the fast growth of distributed RERs, especially solar Photovoltaic (PV) resources. The IEEE 1547a standard relaxed some of the restrictions on utilization of Distributed Energy Resources (DER) in voltage/frequency regulation. Smart inverters may employ different control strategies, such as Fixed Power Factor, Volt-VAR, Volt-Watt, and Frequency-Watt. In this study, a comparison between fixed power factor and Volt-VAR control strategies is performed in terms of voltage regulation capability. One hour of quasi-steady-state simulation with one-second time steps is performed, where fast and frequent irradiance variations are occurring. Parametric studies involving controller settings are used to compare voltage regulation performance. The IEEE 13-bus test feeder, modified by adding two PV generators, is used as the case study. Simulation results show that the Volt-VAR control out performs the fixed power factor control when it comes to voltage regulation.

The primary objective of this paper is to highlight the need for and benefits of studying the steady state and dynamic response of power systems using three phase integrated transmission and distribution (T&D) system models (hereafter referred to as hybrid models). Modeling and simulation requirements for building and analyzing hybrid models are also discussed. Finally, results from steady state and dynamic simulations of a large hybrid model are presented to demonstrate insights that can be obtained from hybrid models which cannot be obtained from the study of transmission and distribution systems separately.

Complex large-scale cyber-physical systems, such as electric power grids, oil & gas pipeline systems, transportation systems, etc. are critical infrastructures that provide essential services for the entire nation. In order to improve systems' security and resilience, researchers have developed many Supervisory Control and Data Acquisition (SCADA) test beds for testing the compatibility of devices, analyzed the potential cyber threats/vulnerabilities, and trained practitioners to operate and protect these critical systems. In this paper, we describe a new test bed architecture for modeling and simulating power system related research. Since the proposed test bed is purely software defined and the communication is emulated, its functionality is versatile. It is able to reconfigure virtual systems for different real control/monitoring scenarios. The unified architecture can seamlessly integrate various kinds of system-level power system simulators (real-time/non real-time) with the infrastructure being controlled or monitored with multiple communication protocols. We depict the design methodology in detail. To validate the usability of the test bed, we implement an IEEE 39-bus power system case study with a power flow analysis and dynamics simulation mimicking a real power utility infrastructure. We also include a cascading failure example to show how system simulators such as Power System Simulator for Engineering (PSS/E), etc. can seamlessly interact with the proposed virtual test bed.

This paper provides an overview of hyperloop technologies, including a brief discussion of key components of a hyperloop system that determine the electric power requirements as a function of time. At-scale hyperloop systems do not yet exist, so a model was used to generate a set of load profiles for conceptual hyperloop realizations at four locations in the United States: two systems in California and one each in Colorado and Ohio. In all four cases, the modeled hyperloop load profiles included pulses in both active and reactive power. Grid modeling was performed to estimate the grid impacts and for discussing grid integration challenges. The paper discusses how energy storage systems might be used to eliminate the pulsating load characteristics or significantly reduce it to accommodate current grid planning guidelines.