scholarly journals EFFECT of DG Optimizing on overload Transmission line Stability

2018 ◽  
Vol 225 ◽  
pp. 03023 ◽  
Author(s):  
Ali Abdullah Ali ◽  
Ahmed N Abdalla ◽  
R. Ishat
Keyword(s):  
Power Systems ◽  
Transmission Line ◽  
System Analysis ◽  
Reactive Power ◽  
Low Voltage ◽  
Heavy Load ◽  
Worst Case ◽  
Light Load ◽  
The Impact ◽  
Load Conditions

Typical steady state studies always treat the peak power demands as the worst case conditions. Periods of light load are also critical in the assessment of the possible state of a power system. While heavy load conditions are generally associated with overload, low voltage and generation deficiency, light load conditions may give rise to over-voltage and undesirable reactive power requirements at generation side. This paper focus on study the effect of DG Optimizing on overload Transmission line Stability. The system dispatch constraints should be taken into account to compensate or varying DG generation output and to enhance the operational performance of power systems. This dispatching operation depends on the change of DG generation and the dispatching strategy. The impact of DG generation uncertainty is limited with the generation dispatching operation and should not be neglected in system analysis.

Study on the Impact of Distributed Generation on Distribution Power Losses

2014 ◽  
Vol 960-961 ◽  
pp. 1460-1464
Author(s):  
Hao Jie Shi ◽  
Xing Ying Chen ◽  
Kai Chen ◽  
Jian Liu ◽  
Kun Yu
Keyword(s):  
Distributed Generation ◽  
Power Flow ◽  
Reactive Power ◽  
Power Losses ◽  
Power Flow Calculation ◽  
Heavy Load ◽  
Light Load ◽  
Network Losses ◽  
Compensation Device ◽  
The Impact

The impact of distributed generation (DG) on distribution power losses is closely related to DG technologies and load distribution. DG units are modeled as PQ, PQ(V) and PV nodes in power flow calculation. A revised back/forward power flow method is employed to calculate distribution power flow with various types of DG units. Power losses are computed when different types of DG units are connected to heavy load, general load and light load area apart. Simulation on IEEE 33-bus distribution network shows that connecting DG to heavy load area helps to maximize the loss reduction. And the installation of DG consuming reactive power will increase network losses unless reactive power compensation device is installed accordingly.

scholarly journals Uncontrolled Electric Vehicle Charging Impacts on Distribution Electric Power Systems with Primarily Residential, Commercial or Industrial Loads

Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1688 ◽  
Author(s):  
C. Birk Jones ◽  
Matthew Lave ◽  
William Vining ◽  
Brooke Marshall Garcia
Keyword(s):  
Power Systems ◽  
Electric Power ◽  
Low Voltage ◽  
Peak Load ◽  
Electric Power Systems ◽  
Primary System ◽  
Maximum Increase ◽  
Actual Distribution ◽  
The Impact ◽  
Ev Charging

An increase in Electric Vehicles (EV) will result in higher demands on the distribution electric power systems (EPS) which may result in thermal line overloading and low voltage violations. To understand the impact, this work simulates two EV charging scenarios (home- and work-dominant) under potential 2030 EV adoption levels on 10 actual distribution feeders that support residential, commercial, and industrial loads. The simulations include actual driving patterns of existing (non-EV) vehicles taken from global positioning system (GPS) data. The GPS driving behaviors, which explain the spatial and temporal EV charging demands, provide information on each vehicles travel distance, dwell locations, and dwell durations. Then, the EPS simulations incorporate the EV charging demands to calculate the power flow across the feeder. Simulation results show that voltage impacts are modest (less than 0.01 p.u.), likely due to robust feeder designs and the models only represent the high-voltage (“primary”) system components. Line loading impacts are more noticeable, with a maximum increase of about 15%. Additionally, the feeder peak load times experience a slight shift for residential and mixed feeders (≈1 h), not at all for the industrial, and 8 h for the commercial feeder.

Toward Online Control of Local Bifurcation in Power Systems via Network Topology Optimization

2015 ◽  
Vol 25 (12) ◽  
pp. 1550167
Author(s):  
Lei Wang ◽  
Hsiao-Dong Chiang
Keyword(s):  
Topology Optimization ◽  
Power Systems ◽  
Transmission Line ◽  
Network Topology ◽  
Online Control ◽  
Power Grids ◽  
Local Bifurcations ◽  
Network Topology Optimization ◽  
Online Methods ◽  
The Impact

This paper presents online methods for controlling local bifurcations of power grids with the goal of increasing bifurcation values (i.e. increasing load margins) via network topology optimization, a low-cost control. In other words, this paper presents online methods for increasing power transfer capability subject to static stability limit via switching transmission line out/in (i.e. disconnecting a transmission line or connecting a transmission line). To illustrate the impact of network topology on local bifurcations, two common local bifurcations, i.e. saddle-node bifurcation and structure-induced bifurcation on small power grids with different network topologies are shown. A three-stage online control methodology of local bifurcations via network topology optimization is presented to delay local bifurcations of power grids. Online methods must meet the challenging requirements of online applications such as the speed requirement (in the order of minutes), accuracy requirement and robustness requirement. The effectiveness of the three-stage methodology for online applications is demonstrated on the IEEE 118-bus and a 1648-bus practical power systems.

scholarly journals Photovoltaic Power Converter Management in Unbalanced Low Voltage Networks with Ancillary Services Support

Energies ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 972 ◽  
Author(s):  
Fermín Barrero-González ◽  
Victor Pires ◽  
José Sousa ◽  
João Martins ◽  
María Milanés-Montero ◽  
...  
Keyword(s):  
Power Flow ◽  
Reactive Power ◽  
Low Voltage ◽  
Renewable Energy Sources ◽  
Distribution Network ◽  
Power Converter ◽  
Maximum Energy ◽  
Practical Implementation ◽  
Network Operation ◽  
The Impact

The proliferation of residential photovoltaic (PV) prosumers leads to detrimental impacts on the low-voltage (LV) distribution network operation such as reverse power flow, voltage fluctuations and voltage imbalances. This is due to the fact that the strategies for the PV inverters are usually designed to obtain the maximum energy from the panels. The most recent approach to these issues involves new inverter-based solutions. This paper proposes a novel comprehensive control strategy for the power electronic converters associated with PV installations to improve the operational performance of a four-wire LV distribution network. The objectives are to try to balance the currents demanded by consumers and to compensate the reactive power demanded by them at the expense of the remaining converters’ capacity. The strategy is implemented in each consumer installation, constituting a decentralized or distributed control and allowing its practical implementation based on local measurements. The algorithms were tested, in a yearly simulation horizon, on a typical Portuguese LV network to verify the impact of the high integration of the renewable energy sources in the network and the effectiveness and applicability of the proposed approach.

Research and Application of SVC Technology in Grid

2014 ◽  
Vol 543-547 ◽  
pp. 878-883
Author(s):  
Jun Dong ◽  
Jian Guo Xu ◽  
Hao Zhang ◽  
Yu Jie Pei ◽  
Xian Feng Li
Keyword(s):  
Power Systems ◽  
Power Quality ◽  
Distribution System ◽  
Power Flow ◽  
Reactive Power ◽  
Control Strategies ◽  
Load Capacity ◽  
Flow Distribution ◽  
Nonlinear Load ◽  
The Impact

The cause serious deterioration in power quality problems for the growing impact and nonlinear load capacity, introduced SVC device in the role of modern power systems and applications. According to the lack of adequate regional dynamic reactive power regulation means to cause voltage fluctuations, harmonics exceeded the actual situation, through analysis and simulation of the existing 66kV grid power quality conditions, refers to the necessity of application of SVC, the compensation capacity for SVC, filter capacitor system parameters and control strategies were designed, the results show improved 220kV SVC reactive power flow distribution system, reducing the system once or twice a net loss, reducing the impact and harmonic interference voltage caused by nonlinear loads, system security, economic operation of great significance.

Performance of the Grid-Connected PV System in LV Microgrid Operation

2012 ◽  
Vol 512-515 ◽  
pp. 137-142
Author(s):  
Yan Li ◽  
Li Wang ◽  
Pan Pan Jing ◽  
Bin Bin Zhong ◽  
Bu Han Zhang ◽  
...  
Keyword(s):  
Power Systems ◽  
Power System ◽  
System Analysis ◽  
Low Voltage ◽  
Environmental Benefits ◽  
Pv System ◽  
Load Curve ◽  
Power System Analysis ◽  
Pv Penetration ◽  
Flexible Operation

Microgrids are a future power system configuration providing clear economic and environmental benefits compared to the legacy power systems, as the Grid-Connected PV penetration increases, its reaction in Low Voltage (LV) microgrid has to be taken into account during relative system studies. This paper presents a mathematical model for the Grid-Connected PV, it’s developed by User Define (UD) module on Power System Analysis Software Package (PSASP), PV behavior under several typical weather and typical 1-day load curve is studied in detail, Flexible Operation Strategy to achieve the reasonable voltage level are both considered, PSASP simulation environment is used to analyze the probable operation scenarios of LV microgrid, useful conclusions are summarized at last.

scholarly journals Improving voltage profile of load bus of wind generation system using DSTATCOM

2017 ◽  
Vol 26 (4) ◽  
pp. 81
Author(s):  
Manju Aggarwal ◽  
Madhusudan Singh ◽  
S.K. Gupta
Keyword(s):  
Distribution System ◽  
Voltage Stability ◽  
Reactive Power ◽  
Low Voltage ◽  
Stability Margin ◽  
Wind Generation ◽  
Voltage Profile ◽  
Generation System ◽  
Wind Generation System ◽  
The Impact

In a low voltage distribution system with integrated wind plant, voltage stability is impacted by the large variation of load and wind penetration. The compensators like SVC and DSTATCOM are currently being used to address such issue of voltage instability. This paper analyses the impact of wind penetration and variation of active and reactive power of the load on voltage profile of a wind generation system with and without DSTATCOM. It also analyses the performance of the system during fault by calculating various parameters of the system. It has been demonstrated that voltage stability margin increases using DSTATCOM at different wind penetration levels. This system has been simulated and analysed in MATLAB 2011b using a power system toolbox under steady state and transient conditions.

scholarly journals Optimized Hip-Knee-Ankle Exoskeleton Assistance Reduces the Metabolic Cost of Walking With Worn Loads

2021 ◽  
Author(s):  
Gwendolyn M Bryan ◽  
Patrick Franks ◽  
Seungmoon Song ◽  
Ricardo Reyes ◽  
Meghan O’Donovan ◽  
...  
Keyword(s):  
Body Weight ◽  
Muscle Activity ◽  
Metabolic Cost ◽  
Load Carriage ◽  
Heavy Load ◽  
Human In The Loop ◽  
Light Load ◽  
Wide Range ◽  
Ankle Exoskeleton ◽  
Load Conditions

Abstract BackgroundLoad carriage is a typical activity in a wide range of professions, but prolonged load carriage is associated with increased fatigue and overuse injuries. Exoskeletons could improve the quality of life of these professionals by reducing metabolic cost to combat fatigue and reducing muscle activity to prevent injuries. Current exoskeletons have reduced the metabolic cost of loaded walking by up to 23% when assisting one or two joints. Greater metabolic reductions may be possible with optimized assistance of the entire leg. MethodsWe used human-in the-loop optimization to optimize hip-knee-ankle exoskeleton assistance with no additional load, a light load (15% of body weight), and a heavy load (30% of body weight) for three participants. All loads were applied through a weight vest with an attached waist belt. We measured metabolic cost, exoskeleton assistance, kinematics, and muscle activity. We performed one-tailed paired t-tests to determine significant reductions for metabolic cost and muscle activity, and we performed an analysis of variance (ANOVA) to determine significant changes across load conditions for metabolic cost and applied power. ResultsExoskeleton assistance reduced the metabolic cost of walking relative to walking in the device without assistance for all tested conditions. Exoskeleton assistance reduced the metabolic cost of walking by 47% with no load (p = 0.02), 35% with the light load (p = 0.03), and 43% with the heavy load (p = 0.02). The smaller metabolic reduction with the light load may be due to insufficient participant training or lack of optimizer convergence. The total applied positive power was similar for all tested conditions, and the positive knee power decreased slightly as load increased. Optimized torque timing parameters were consistent across participants and load conditions while optimized magnitude parameters varied. ConclusionsWhole-leg exoskeleton assistance can reduce the metabolic cost of walking while carrying a range of loads. The consistent optimized timing parameters suggest that metabolic cost reductions are sensitive to torque timing. The variable torque magnitude parameters could imply that torque magnitude should be customized to the individual, or that there is a range of useful torque magnitudes. Future work should test whether applying the load to the exoskeleton rather than the person's torso results in larger benefits.

scholarly journals Optimal Allocation of Static Var Compensators in Electric Power Systems

Energies ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 3219 ◽  
Author(s):  
Martin Ćalasan ◽  
Tatjana Konjić ◽  
Katarina Kecojević ◽  
Lazar Nikitović
Keyword(s):  
Power Systems ◽  
Power System ◽  
Optimal Power Flow ◽  
Optimal Allocation ◽  
Reactive Power ◽  
Dynamic Performance ◽  
Variable Load ◽  
Power Losses ◽  
Facts Devices ◽  
The Impact

In the current age, power systems contain many modern elements, one example being Flexible AC Transmission System (FACTS) devices, which play an important role in enhancing the static and dynamic performance of the systems. However, due to the high costs of FACTS devices, the location, type, and value of the reactive power of these devices must be optimized to maximize their resulting benefits. In this paper, the problem of optimal power flow for the minimization of power losses is considered for a power system with or without a FACTS controller, such as a Static Var Compensator (SVC) device The impact of location and SVC reactive power values on power system losses are considered in power systems with and without the presence of wind power. Furthermore, constant and variable load are considered. The mentioned investigation is realized on both IEEE 9 and IEEE 30 test bus systems. Optimal SVC allocation are performed in program GAMS using CONOPT solver. For constant load data, the obtained results of an optimal SVC allocation and the minimal value of power losses are compared with known solutions from the literature. It is shown that the CONOPT solver is useful for finding the optimal location of SVC devices in a power system with or without the presence of wind energy. The comparison of results obtained using CONOPT solver and four metaheuristic method for minimization of power system losses are also investigated and presented.

Tribological Behavior and Mechanisms of the Deloro60 Alloy Coatings by Electro Spark Deposition under Dry Sliding Friction Conditions

2014 ◽  
Vol 692 ◽  
pp. 428-432
Author(s):  
Xiao Long Wang ◽  
Ting Xu ◽  
Ye Fa Tan ◽  
Li Zhou An ◽  
Lu Lu Wang ◽  
...  
Keyword(s):  
High Speed ◽  
Sliding Friction ◽  
Base Alloy ◽  
Dry Sliding ◽  
Heavy Load ◽  
Micro Cutting ◽  
Light Load ◽  
Rational Combination ◽  
Dry Sliding Friction ◽  
Load Conditions

The Ni-base alloy coatings of Derolo60 were prepared on the surface of carbon steel by electro spark deposition. The tribological properties of the coatings were investigated in a tribometer under dry sliding friction conditions. The results show that the coatings exhibit excellent properties of wear resistance because of their unique microstructure with a rational combination of hard phases and tough matrix. With the increase of the normal loads and sliding speeds, the friction coefficients of the coatings decrease, while the wear losses increase. The main wear mechanisms of the coatings are micro-cutting wear and multi-plastic deformation wear at low speed and light load conditions, and then gradually change into micro-cutting wear and adhesive wear as well as fatigue fracture accompanied by some oxidation wear at high speed and heavy load conditions.

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