scholarly journals Effect of Neutral Grounding Protection Methods for Compensated Wind/PV Grid-Connected Hybrid Power Systems

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Nurettin Çetinkaya ◽  
Farhana Umer
Keyword(s):  
Power Systems ◽  
Short Circuit ◽  
Simulation Models ◽  
Hybrid Power Systems ◽  
Negative Effects ◽  
Double Line ◽  
Fault Protection ◽  
Ground Fault Protection ◽  
Pv Grid ◽  
The Impact

The effects of the wind/PV grid-connected system (GCS) can be categorized as technical, environmental, and economic impacts. It has a vital impact for improving the voltage in the power systems; however, it has some negative effects such as interfacing and fault clearing. This paper discusses different grounding methods for fault protection of High-voltage (HV) power systems. Influences of these grounding methods for various fault characteristics on wind/PV GCSs are discussed. Simulation models are implemented in the Alternative Transient Program (ATP) version of the Electromagnetic Transient Program (EMTP). The models allow for different fault factors and grounding methods. Results are obtained to evaluate the impact of each grounding method on the 3-phase short-circuit fault (SCF), double-line-to-ground (DLG) fault, and single-line-to-ground (SLG) fault features. Solid, resistance, and Petersen coil grounding are compared for different faults on wind/PV GCSs. Transient overcurrent and overvoltage waveforms are used to describe the fault case. This paper is intended as a guide to engineers in selecting adequate grounding and ground fault protection schemes for HV, for evaluating existing wind/PV GCSs to minimize the damage of the system components from faults. This research presents the contribution of wind/PV generators and their comparison with the conventional system alone.

scholarly journals Investigation of the Impact Factors on the Optimal Intermediate Temperature in a Dual Transcritical CO2 System with a Dedicated Transcritical CO2 Subcooler

Energies ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 309 ◽  
Author(s):  
Yulong Song ◽  
Haidan Wang ◽  
Feng Cao
Keyword(s):  
Simulation Models ◽  
Intermediate Temperature ◽  
Impact Factors ◽  
Outlet Temperature ◽  
Negative Effects ◽  
Pinch Point ◽  
Improvement Potential ◽  
Water Feed ◽  
Performance Deterioration ◽  
The Impact

As a natural fluid with superior environment advantages, CO2 is used to constitute a dual transcritical system to reduce performance deterioration under high gas-cooler outlet temperature. Aiming at the system configuration, improvement potential, and optimization, the proposed system is deeply analyzed, and corresponding coupling models are presented in detail. First, the veracity of simulation models is completely verified by comparing with previous measurements. Then, the existence of the optimal intermediate temperature is validated, while the optimal values are found to increase with the augmentation in ambient and water-feed temperatures. Moreover, the negative effects of the pinch point on the heat transfer inside the gas cooler could be greatly reduced by using the dual gas cooler. Finally, a predictive correlation for optimal intermediate temperature determination with ambient and water-feed temperature as independent variables is proposed, which provides a theoretical basis for the proposed system to realize efficient control in the industrialization process.

scholarly journals Increase of Transient Stability Level of Gas Turbine Power Plant Using FACTS

2019 ◽  
Vol 139 ◽  
pp. 01049
Author(s):  
Sergey Solodyankin ◽  
Andrey Pazderin
Keyword(s):  
Power Systems ◽  
Mathematical Models ◽  
Gas Turbine ◽  
Power Plants ◽  
Transient Stability ◽  
Positive Impact ◽  
Short Circuit ◽  
Important Conclusion ◽  
Facts Devices ◽  
The Impact

The article is devoted to the development of the mathematical models of modern devices of flexible alternating current transmission systems (FACTS) when calculating the modes and stability of power systems and to the analysis of influence of the specified devices on transient stability of the generators. The considered scheme contains the generators with the gas turbine drive that have electromechanical parameters providing lower level of transient stability compared to units of higher power rating, which in some cases requires implementation of measures for transient stability enhancement. As examples of FACTS the following devices have been considered: compensating device based on voltage- sourced converter (STATCOM), static synchronous series compensator (SSSC) and the unified power flow controller (UPFC). The known examples of mathematical models of FACTS devices vary in complexity. For a preliminary assessment of the effectiveness of the FACTS devices, it is proposed to use simplified models that adequately reflect their impact on transients. The use of models made it possible to establish a positive impact of the devices on transient stability of generating equipment in case of short circuits in the electric network. The important conclusion here is that the use of the UPFC device based on two converters (with a corresponding increase in cost) compared to one converter device (STATCOM or SSSC) slightly increases the level of transient stability and the limit time of short circuit disconnection. The proposed method of simulating the FACTS devices is suitable for numerical calculations of transient processes in electric power systems, in particular, to estimate the impact on the transient stability level of the parallel operation of power plants in case of disturbances.

High-voltage electrical equipment in electrical power systems: diagnostics, defects, damage, monitoring

2019 ◽  
Author(s):  
Александр Хренников ◽  
Alexander Khrennikov
Keyword(s):  
Power Systems ◽  
Short Circuit ◽  
Electrical Power ◽  
Electrical Equipment ◽  
Diagnostic Methods ◽  
Power Transformers ◽  
Electrical Power Systems ◽  
The Impact ◽  
Short Circuit Currents ◽  
Detection Of Defects

The analysis of the main methods of diagnostics of electrical equipment for detection of defects and damages in the course of operation is presented. Analysis of the effectiveness of the main diagnostic methods is accompanied by examples of detection of defects and damage to specific equipment: power transformers, reactors, current and voltage transformers, disconnectors, turbogenerators, OPN, etc. Examples of damage and investigation of technological violations of oil-filled transformer-reactor equipment during operation, associated with the loss of electrodynamic resistance of the windings during the flow of through short-circuit currents (short-circuit). The analysis of efficiency of application of methods of diagnostics at detection of defects and damages of power transformers because of the impact of fault current. The questions of electrodynamic tests of power transformers (reactors) for resistance to short-circuit currents, which serve as a tool to improve the reliability of their design, are considered.

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