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In this study, we investigate the impact of the dynamic behavior of photovoltaic (PV) power generation systems on short-term voltage stability of the transmission system. First, the impact of the fault ride-through capability of a PV model is studied by setting several recovery speeds of the active current output when the operation of the PV system is interrupted because of a voltage sag. The results...
The variable and uncertain nature of the leading renewable energy resources, such as wind power generation, imposes the development of a sophisticated balance mechanism between supply and demand to maintain the consistency of a power system. In this study, a two stage stochastic programming model is proposed to procure the required load-following reserves from both generation and demand side resources...
Due to the increasing adoption of domestic photovoltaic (PV) systems, the use of technologies such as on-load tap changer (OLTC)-fitted transformers, capacitor banks, and remote monitoring are being considered to mitigate voltage issues, particularly in European-style low voltage (LV) networks. Depending on the control strategy, however, the effects on customer voltages and control actions (e.g.,...
Introduction of distributed generation (DG) to the power system may lead to nonselective protection actions. For every future DG installation, the relay settings need to be modified to guarantee protection coordination that can lead to numerous changes in relay settings. This paper presents a novel approach to plan relay protection coordination considering future DG installations. Thus, this paper...
A distributed-adaptive droop mechanism is proposed for secondary/primary control of dc microgrids. The conventional secondary control that adjusts the voltage set point for the local droop mechanism is replaced by a voltage regulator. A current regulator is also added to fine-tune the droop coefficient for different loading conditions. The voltage regulator uses an observer that processes neighbors'...
In this paper, a small signal model has been developed for a grid connected photovoltaic (PV)-diesel engine (DE) system feeding also to an induction motor at the low voltage level. The comprehensive mathematical model of the system has been developed by linearizing the system of equations around an operating point. To analyze the stability of the system, the eigen values and thus the modes of the...
DC microgrid provides a viable and more efficient option to cater for DC loads in the building space and, in particular, data centers. This paper investigates the opportunities associated for utilities to optimize industrial demand response for smart AC and DC microgrid environment thus facilitating distribution utility to reduce peak energy on the existing AC distribution system. A load shifting...
This paper proposes a self-healing strategy for two neighboring islanded microgrids (MGs) that are connected together through a normally open interconnecting static switch (ISS). Each MG is expected to support the other during power deficiencies, which is facilitated by the developed self-healing agent. This agent operates based on either a centralized approach, when data communication system is available,...
This paper proposes an algorithm for determining the optimal composition which means number of links and section switches in a feeder and placement of automatic switches in a Distribution Automation System (DAS). A DAS is configured by automatic switches and reclosers on a power distribution line. The composition and placement of switches affect the operational applications of a DAS. More switches...
In this paper, we propose a distributed frequency regulation framework for prosumer-based electric energy systems, where a prosumer (producer-consumer) is defined as an intelligent agent which can produce, consume, and/or store electricity. Despite the frequency regulators being distributed, stability can be ensured while avoiding inter-area oscillations using a limited control effort. To achieve...
This paper presents optimal third harmonics in both permanent magnet (PM) shaping and current waveform to improve the output torque of five-phase surface-mounted PM (SPM) machines. The optimal value of third harmonic injected into the sinusoidal PM shape and current waveform for maximum torque improvement is analytically derived and validated by both finite element (FE) analyses and experiments. It...
Overvoltage is a major limiting factor for the integration of distributed generation in distribution systems. Among various solutions to the overvoltage problem, active power curtailment is an attractive solution since only small adjustments in the controllers are necessary for implementing this technique. Furthermore, it is activated only when needed. In wind energy systems, this can be achieved...
This paper explores control strategies for active power distribution nodes (APDNs) using a hierarchical approach. The proposed APDN consists of multiple bi-directional interface modules and an embedded energy storage that is commonly connected to these modules. Such configuration properties make the APDN attractive as a major interface unit for active power flow control in microgrids and power distribution...
The modular multilevel converter (MMC) has become an attractive option for dc/ac conversion in many power system applications, in particular for HVDC transmission. Due to its parallel arrangement of phase legs the MMC is known to be a wye configured architecture. In this paper, the equivalent delta formulation of the conventional wye architecture is introduced. The delta configured MMC, enabled by...
This paper proposes a methodology to efficiently estimate the probability of small-disturbance rotor angle instability of uncertain power systems. Traditional Monte Carlo (MC) approaches are computationally intensive and inefficient, particularly when used to study low probability conditions which result in small disturbance instabilities and develop into serious outage events high impact. The proposed...
Increasing penetration of renewable power sources (RESs) is bringing more uncertainties to power systems. Real-time economic dispatch should be able to handle the fluctuations caused by the load as well as RESs, and obtain new optimal operating points after deviating from original generation schedules. This paper proposes a generation adjustment algorithm based on the base point and participation...
With the increased environmental concern, the photovoltaic (PV) generation capacity is growing in today's power systems. As the PV penetration rate increases, the intermittency and uncertainty of PV systems will cause frequency regulation issues. When rapid fluctuations take place, the system requires fast responding regulation to recover the frequency within a short period of time. Traditional power...
In this paper, we explore the portfolio effect of a system consisting of a combined heat and power (CHP) plant and a wind farm. The goal is to increase the overall profit of the portfolio by reducing imbalances and, consequently, their implicit penalty in a two-price balancing market for electricity. We investigate two different operational strategies, which differ in whether the CHP plant and the...
Uniform marginal pricing cannot generally support competitive equilibrium solutions in markets with non-convexities, yielding surplus sub-optimality effects. Previous work has identified non-convexities associated with the generation side of electricity markets and proposed different approaches to address surplus sub-optimality. This paper extends this concept to incorporate the demand side. Non-convexities...
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