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In recent years, due to high demand for electrical energy both in commercial and residential sectors, power systems often operate close to their operational limits. However, transients caused by load variation, faults and large set point changes can cause an apparatus violates its operational limits and different subsequent attentional problems such as instability and tripping of protective devices...
Accuracy of synchrophasor measurements is one of the key issues directing the application of synchrophasor/PMU technologies in both transmission and distribution systems. This paper introduces a dynamic phasor estimation method for PMUs/IEDs based on modified time domain hybrid method. Dynamic phasor is estimated using Taylor expansion, where frequency deviation is derived directly from fitting parameters...
This paper proposes a modular microgrid unit (MMGU) that can work autonomously but is also capable of connecting to other MMGUs to form an expandable microgrid. Because of various types of resources and power lines, the proposed unit is reliable and robust enough to protect against single failures and generation fluctuation. Storage units are included to enhance the overall performance of the microgrid...
Centralized system protection and emergency control schemes are playing critical roles in maintaining the stability of modern power system. Being able to make optimal decisions based on global information and coordinate complex protection/control activities is the most desirable feature of a centralized scheme. On the other hand, centralized intelligence is quite vulnerable to various malicious cyber...
With the rapidly growing penetration of wind power, photoelectricity and other renewables, the problems of subsynchronous resonances/oscillations resulting from the interaction between power-electronic converters and the transmission devices have become increasingly prominent. In these cases, there would be continuous subsynchronous power oscillations or sub- and supersynchronous voltage and current...
In this paper we propose and demonstrate the potential for unifying models and algorithms for the steady state and transient simulation of single-phase and three-phase power systems. At present, disparate algorithms and models are used for the different analyses, which can lead to inconsistencies - such as the transient analysis as time approaches infinity not matching the steady state analysis of...
This paper proposes a decentralized fast-response voltage/VAR control (VVC) using inverters in a distribution grid with a high penetration of photovoltaic (PV) generation. The reactive power compensation/absorption of PV inverters are controlled and coordinated by the proposed VVC strategy with an adaptive time delay to maintain the system voltage within a desired range. The convergence and stability...
In this paper, we propose a decoupled substation price model with separate charges for base energy production, up/down reserve usages and reserve usage variations. Using the decoupled price scheme, the flexible loads in the distribution system are scheduled to closely follow variations in renewable generation in order to mitigate demand fluctuations in substation. This reduces the need for reserve...
This paper mainly focuses on statistical analysis of transmission line capacities in terms of both topology and electrical parameters. We expand our earlier work on random-topology power grid modeling as a way to generate synthetic grid data to test new concepts and designs. We examine transmission line capacities based on both network topology metrics and a newly proposed electrical index called...
Sensors in the smart grid provide a way for utilities to obtain measurements that can be used to assess grid health. However, the vast majority of physical grid assets do not have sensors attached to them. For example, a utility may have hundreds of thousands of poles, many of which are part of an aging physical infrastructure. The utility, however, does have a wealth of information concerning pole...
Global warming and the depletion of fossil fuels encourage installing a large scale PV (photovoltaic) system. The large scale PV system may cause a issue of the voltage rise at an interconnection point due to the reverse power flow. This paper investigates the distributed management problem of PCSs (power conditioning systems) which are used to interconnect the PV system to the power gird. We consider...
Grid-scale energy storage systems are attracting more attention because of increased public-awareness and declining prices. However, there is still one question which needs to be answered: when utilization of Battery Storage System (BSS) is economical? To address this question, problems of simultaneously sizing BSSs and optimal power sharing -with an objective of decreasing daily operational cost-...
As more renewable energy sources (solar, wind, hydro, etc.) are being incorporated into the smart grid, the problem of balancing generation and load demand gets more attention in the field of power system optimal economic operation. As a solution, grid-level energy storage systems (ESSs) have been used to increase the efficiency of the power supply by smoothing load fluctuations. In this paper, monotone...
Lighting systems consume lots of energy so efficient solutions are strongly desired. This study proposes two smart lighting solutions using state-of-the-art technologies, namely LED and sensor-based control. The solutions reduce the lighting energy usage significantly. A case study with a large animal protection shelter shows that the energy usage decreases to 43% (with Solution 1) and 36.4% (with...
The large scale deployment of renewable generation is generally seen as the most promising option for displacing fossil fuel generators, especially coal-fired power plants. A key challenge in integrating Renewable Energy Resources (RERs) is to find approaches that ensure long term sustainability and economic profit. One approach for mitigating the variability issue of integrating RERs is Demand Response...
Phasor measurement units (PMUs) provide real-time synchrophasor data and good situational awareness of power grid, and could be used to take corrective actions to maintain grid reliability. Thousands of PMUs deployed in the North American power grid are supplied by a number of different PMU vendors. Synchrophasor data exchange, sharing and interoperability are major challenges for the power industry...
This paper investigates the potential of residential heating, ventilation and air conditioning systems to contribute to dynamic demand-side management. Thermal models for seven houses in Austin, Texas are developed with the goal of using them in a planning based demand-side management methodology. The thermal models form the base to determine the flexibility present in these houses with respect to...
Phasor Measurement Units (PMUs) measure voltage and current phasors at the same time and relative to the same angle reference, so that it is feasible to use a Linear State Estimator (LSE) to provide a full system solution from these measurements. This paper explores the practical issues of LSE implementation using a phasor measurement system in the Western Electricity Coordinating Council (WECC) system...
Cyber Physical Systems (CPS) security testbeds serve as a platform for evaluating and validating novel CPS security tools and technologies, accelerating the transition of state-of-the-art research to industrial practice. The engineering of CPS security testbeds requires significant investments in money, time and modeling efforts to provide a scalable, high-fidelity, real-time attack-defense platform...
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