Impact of controllable superconducting series reactor in transient recovery voltage of circuit breaker

Series reactors as fault current limiters (FCLs) are extensively employed to enhance power grid protection issues. Utilizing superconducting technology is a viable solution to approach FCLs toward commercializing. The concern of transient recovery voltage (TRV) of the circuit breaker becomes more considerable due to FCL’s high stored energy in the case of fault current limiting mode. This paper firstly focuses on the analysis of TRV under the presence of an inductive-based superconducting fault current limiter (SFCL) installed in a power grid, and then it investigates the impact of a controllable superconducting series reactor (CSSR) in TRV of the circuit breaker. The obtained results show that the synchronous operation of a CSSR with a circuit breaker substantially declines TRV

Impact of controllable superconducting series reactor in transient recovery voltage of circuit breaker

Series reactors as fault current limiters (FCLs) are extensively employed to enhance power grid protection issues. Utilizing superconducting technology is a viable solution to approach FCLs toward commercializing. The concern of transient recovery voltage (TRV) of the circuit breaker becomes more considerable due to FCL’s high stored energy in the case of fault current limiting mode. This paper firstly focuses on the analysis of TRV under the presence of an inductive-based superconducting fault current limiter (SFCL) installed in a power grid, and then it investigates the impact of a controllable superconducting series reactor (CSSR) in TRV of the circuit breaker. The obtained results show that the synchronous operation of a CSSR with a circuit breaker substantially declines TRV

The Use of System in the Loop, Hardware in the Loop, and Co-modeling of Cyber-Physical Systems in Developing and Evaluating New Smart Grid Solutions

This paper deals with two issues: development of some advanced smart grid applications, and implementation of advanced testbeds to evaluate these applications. In each of the development cases, the role of the testbeds is explained and evaluation results are presented. The applications cover the synchrophasor systems, interfacing of microgrids to the main grid, and cybersecurity solutions. The paper hypothesizes that the use of the advanced testbeds is beneficial for the development process since the solution product-to-market cycle may be shortened due to early real-life demonstrations. In addition, solution users’ feedback to the testbed demonstration can be incorporated at an early stage when making the changes is not as costly as doing it at more mature development stages

Facilitating the transition to an inverter dominated power system : experimental evaluation of a non-intrusive add-on predictive controller

The transition to an inverter-dominated power system is expected with the large-scale integration of distributed energy resources (DER). To improve the dynamic response of DERs already installed within such a system, a non-intrusive add-on controller referred to as SPAACE (set point automatic adjustment with correction enabled), has been proposed in the literature. Extensive simulation-based analysis and supporting mathematical foundations have helped establish its theoretical prevalence. This paper establishes the practical real-world relevance of SPAACE via a rigorous performance evaluation utilizing a high fidelity hardware-in-the-loop systems test bed. A comprehensive methodological approach to the evaluation with several practical measures has been undertaken and the performance of SPAACE subject to representative scenarios assessed. With the evaluation undertaken, the fundamental hypothesis of SPAACE for real-world applications has been proven, i.e., improvements in dynamic performance can be achieved without access to the internal controller. Furthermore, based on the quantitative analysis, observations, and recommendations are reported. These provide guidance for future potential users of the approach in their efforts to accelerate the transition to an inverter-dominated power system

Load frequency control in variable inertia systems

Conventional load frequency control primarily relies on large synchronous generation units to ensure regulation of the system frequency. However, its performance deteriorates as the system parameters, including inertia and droop coefficients, deviate from original system design. This letter proposes an augmented load frequency control (ALFC) to ensure robust frequency regulation under diurnal variations in system parameters that are expected in the future, renewables-rich power system. The superior performance of ALFC is demonstrated by several case studies, and its stability is assessed by small-signal analysis

An improved nine‐level switched capacitor‐based inverter with voltage boosting capability and limitation of capacitor current spikes for PV applications

To proceed to a net zero carbon world and to mitigate the environmental challenges associated with it, integration speed of renewable energy sources such as photovoltaic (PV) systems has been increased around the world. Here, an improved switched-capacitor based nine-level inverter is introduced for PV applications. This topology has several benefits such as, voltage boosting feature, using a single DC source, reduction of capacitor charging current spike and extendable input voltage. This inverter produces nine-level output voltage waveform using single power supply. This topology, using identical two capacitors in parallel with a single DC source, can boost the input voltage. In this inverter to limit spike current of capacitor charging mode, an inductor is placed in the charging path of capacitors with a parallel diode. The power losses and overall efficiency analysis of the improved inverter are considered. To verify the accurate performance of inverter under a step change on power flows, simulation results are obtained by MATLAB/Simulink software and presented. To highlight the benefits of the inverter, a comparison of improved topology with most recent topologies is performed. Finally, to verify the feasibility and performance of the improved inverter, experimental results of a 770 W grid-tied prototype are presented

Control Strategies for the Next Generation Microgrids

In the context of the envisioned electric power delivery system of the future, the smart grid, this dissertation focuses on control and management strategies for integration of distributed energy resources in the power system. This work conceptualizes a hierarchical framework for the control of microgrids---the building blocks of the smart grid---and develops the notion of potential functions for the secondary control for devising intermediate set points to ensure feasibility of operation of the system. A scalar potential function is defined for each controllable unit of the microgrid such that its minimization corresponds to achieving the control goal. The set points are dynamically updated using communication within the microgrid. This strategy is generalized to (i) include both local and system-wide constraints and (ii) allow a distributed implementation. This dissertation also proposes and evaluates a simple yet elaborate distributed strategy to mitigate the transients of controllable devices of the microgrid using local measurements. This strategy is based on response monitoring and is augmented to the existing controller of a power system device. This strategy can be implemented based on either set point automatic adjustment (SPAA) or set point automatic adjustment with correction enabled (SPAACE) methods. SPAA takes advantage of an approximate model of the system to calculate intermediate set points such that the response to each one is acceptable. SPAACE treats the device as a generic system and monitors its response and modulates its set point to achieve the desired trajectory. SPAACE bases its decisions on the trend of variations of the response and accounts for inaccuracies and unmodeled dynamics. Case studies using the PSCAD/EMTDC software environment and MATLAB programming environment are presented to demonstrate the application and effectiveness of the proposed strategies in different scenarios.Ph