scholarly journals METHOD OF ASYNCHRONOUS ENGINES EQUIVALENCY FOR CALCULATING SHORT CIRCUIT CURRENT IN A SYSTEM OF BALANCE-OF-PLANT NEEDS

2020 ◽  
pp. 102-115
Author(s):  
Abdullo Sh. Majidov ◽  
Yury P. Gusev
Keyword(s):  
Power Plant ◽  
Power Plants ◽  
Low Voltage ◽  
Short Circuit ◽  
Balance Of Power ◽  
Short Circuit Current ◽  
Initial Moment ◽  
Plant Design ◽  
Balance Of Plant ◽  
Asynchronous Motors

In short-circuiting in power plants of balance-of-power plant needs three-phase asynchronous motors with a short-closed rotor have a significant influence on the nature of the process and the magnitude of the short circuit current. In the system of balance-of-plant needs it is necessary to take into account the components of short circuit current from asynchronous motors when selecting and checking switches, as well as when selecting and checking current-carrying parts (cables, complete current wires, etc.) not only at the initial moment of the short circuit, but at the time of its shutdown as well. The methods for calculating short circuit current taking into account the influence of asynchronous motors continue to be improved; there is a search for new methods that simplify calculations as much as possible while maintaining the credibility of the results. In doing so, some issues require further study and research, such as the possibility of asynchronous motors equivalency. Power plants have to take into account the components of the short circuit current from a large number of asynchronous engines, which is not only time-consuming, but sometimes impossible due to the absence of full information on engines and mechanisms of balance-of-plant needs. To improve the efficiency and accuracy of calculations for power plant design tasks, it is advisable to replace asynchronous engine groups with equivalents. The relevance of improving the method of equivalency of asynchronous engines at power plants increases along with increasing requirements to enhance the reliability of electrical installations of balance-of-power plant needs and to reduce the costs of technical inventory due to calculation errors. The article considers the method for equivalencing the group of low-voltage asynchronous motors on the example of the balance-of-plant needs system at TPP № 1 located in the town of Dushanbe of the Republic of Tajikistan. Modeling the electromechanical processes caused by short circuits of different electrical remoteness was carried out using ETAP software complex (OTI, USA).

scholarly journals Analisis Kinerja Relai Arus Lebih pada PLTU Embalut PT. Cahaya Fajar Kaltim Unit 1×60 MW dengan Simulasi

2020 ◽  
Vol 17 (2) ◽  
pp. 123
Author(s):  
Agung Prasetyo ◽  
Rusda Rusda ◽  
Masing Masing
Keyword(s):  
Power Plant ◽  
Power Plants ◽  
Short Circuit ◽  
Characteristic Curve ◽  
Short Circuit Current ◽  
Electrical Equipment ◽  
Protection System ◽  
East Kalimantan ◽  
Overcurrent Relays ◽  
Overcurrent Relay

Embalut power plant is one of the power plants that supply electricity in East Kalimantan. The plant which is operated by PT. Cahaya Fajar Kaltim, has one PLTU unit with a capacity of 2x25 MW and another with the capacity of 1x60 MW. As an electricity company that must keep continuity of electric supply to customers, a reliable electrical system is necessary. Such reliable system requires protection system to detect a problem and avoid electrical equipment damage. A proper protection system should isolate the affected area and prevent black out on the other area. A type of problem may occur is a short circuit. This study analyzes the performance of overcurrent relays in 1 × 60 MW power plant unit. The analysis was performed through ETAP 12.6.0 software which was also used to design the single line diagrams, calculate the setting currents of short circuit current, also to simulate the coordination of several overcurrent relays in the system. Adjustment of the current and time value in the overcurrent relay is obtained from the result of manual calculations. The results then are displayed in the form of a characteristic curve. Afterwards, a simulation is performed in a situation where three-phase short circuit occurs at BFWP 1.3 Bus, TR AUX.3 Bus and TR 3A.3 Bus. The results show that the overcurrent relays work properly and could overcome the problem quickly.

scholarly journals Thermal Analysis of Heat Distribution in Busbars during Rated Current Flow in Low-Voltage Industrial Switchgear

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2427
Author(s):  
Michał Szulborski ◽  
Sebastian Łapczyński ◽  
Łukasz Kolimas
Keyword(s):  
Structural Changes ◽  
Heat Dissipation ◽  
Current Flow ◽  
Low Voltage ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Coupled Analysis ◽  
Precise Representation ◽  
Transient Thermal ◽  
Halogen Free

The manuscript presents advanced coupled analysis: Maxwell 3D, Transient Thermal and Fluent CFD, at the time of a rated current occurring on the main busbars in the low-voltage switchgear. The simulations were procured in order to aid the design process of such enclosures. The analysis presented the rated current flow in the switchgear busbars, which allowed determining their temperature values. The main assumption of the simulation was measurements of temperature rise during rated current conditions. Simulating such conditions is a valuable asset in order to design better solutions for energy distribution gear. The simulation model was a precise representation of the actual prototype of the switchgear. Simulations results were validated by experimental research. The heat dissipation in busbars and switchgear housing through air convection was presented. The temperature distribution for the insulators in the rail bridge made of fireproof material was considered: halogen-free polyester. The results obtained during the simulation allowed for a detailed analysis of switchgear design and proper conclusions in practical and theoretical aspects. That helped in introducing structural changes in the prepared prototype of the switchgear at the design and construction stages. Deep analysis of the simulation results allowed for the development concerning the final prototype of the switchgear, which could be subjected to the full type tests. Additionally, short-circuit current simulations were procured and presented.

scholarly journals Performance and Economic Assessment of a Grid-Connected Photovoltaic Power Plant with a Storage System: A Comparison between the North and the South of Italy

Energies ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 2356 ◽  
Author(s):  
Ferdinando Chiacchio ◽  
Fabio Famoso ◽  
Diego D’Urso ◽  
Luca Cedola
Keyword(s):  
Power Plant ◽  
Power Plants ◽  
Low Voltage ◽  
Storage System ◽  
Economic Feasibility ◽  
The South ◽  
Model Based ◽  
The North ◽  
Photovoltaic Power ◽  
Historical Series

Grid-connected low voltage photovoltaic power plants cover most of the power capacity installed in Italy. They offer an important contribution to the power demand of the utilities connected but, due to the nature of the solar resource, the night-time consumption can be satisfied only withdrawing the energy by the national grid, at the price of the energy distributor. Thanks to the improvement of storage technologies, the installation of a system of battery looks like a promising solution by giving the possibility to increase auto-consumption dramatically. In this paper, a model-based approach to analyze and discuss the performance and the economic feasibility of grid-connected domestic photovoltaic power plants with a storage system is presented. Using as input to the model the historical series (2008–2017) of the main ambient variables, the proposed model, based on Stochastic Hybrid Fault Tree Automaton, allowed us to simulate and compare two alternative technical solutions characterized by different environmental conditions, in the north and in the south of Italy. The performances of these systems were compared and an economic analysis, addressing the convenience of the storage systems was carried out, considering the characteristic useful-life time, 20 years, of a photovoltaic power plant. To this end the Net Present Value and the payback time were evaluated, considering the main characteristics of the Italian market scenario.

Comparison of Plant Response of Forsmark 3 Nuclear Power Plant to Forsmark 1 Type of Transient (25th July 2006), Using the HAMBO BWR Simulator: Thermal-Hydraulic Aspects

2008 ◽  
Author(s):  
Esko Pekkarinen
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Short Circuit ◽  
Complex Interplay ◽  
Operator Interface ◽  
Control Rooms ◽  
Hydraulic Process

Modernisation of control rooms of the nuclear power plants has been a major issue during the last few years. With this as a basis, the BWR plants in Sweden and Finland funded, in co-operation with the Halden Project, an experimental HAMBO BWR simulator project based on the Forsmark 3 plant in Sweden. VTT Energy in Finland developed the simulator models for HAMBO with the aid of their APROS tool, while the operator interface was developed by the Halden Project. The simulator and its performance have been described in other publications [1, 2]. On July 25th 2006 there was a short circuit at Forsmark 1 nuclear power plant when manoeuvring equipment in the 400kV-switch yard. Due to the short circuit, the plant suffered an electrical disturbance that led to scram and failure of two out of four diesel generators. The purpose of the study carried out at VTT in 2007 was to assess the capabilities of the HAMBO BWR simulator to handle Forsmark 1 type of events in different nuclear power plants (Forsmark 3 in this case). The Forsmark 1 incident showed (among other things) that the intention to protect certain components (in this case the UPS-system) can in certain situations affect negatively to the safety functions. It is concluded that most of this type of BWR transients may be simulated to a certain extent using the existing HAMBO- and APROS- models. A detailed modelling of the automation and electric systems is required sometimes if the complex interplay between these systems and the process is to be predicted reliably. The modelling should be plant specific and level of detail should be assessed case-by-case (i.e. what kind of transient is in question, what systems are available, what is the main purpose of the analyses etc.). The thermal-hydraulic models of the APROS-code seem to replicate well the real behaviour of thermal-hydraulic process provided that there is enough information about the transient in consideration.

scholarly journals Modelling and Stability Analysis of Wind Power Plants Connected to Weak Grids

2019 ◽  
Vol 9 (21) ◽  
pp. 4695 ◽  
Author(s):  
Esmaeil Ebrahimzadeh ◽  
Frede Blaabjerg ◽  
Torsten Lund ◽  
John Godsk Nielsen ◽  
Philip Carne Kjær
Keyword(s):  
Power Plant ◽  
Wind Turbine ◽  
Wind Power ◽  
Power Plants ◽  
Short Circuit ◽  
Wind Power Plant ◽  
Negative Sequence ◽  
Weak Grid ◽  
Wind Power Plants ◽  
Sequence Domain

It is important to develop modelling tools to predict unstable situations resulting from the interactions between the wind power plant and the weak power system. This paper presents a unified methodology to model and analyse a wind power plant connected to weak grids in the frequency-domain by considering the dynamics of the phase lock loop (PLL) and controller delays, which have been neglected in most of the previous research into modelling of wind power plants to simplify modelling. The presented approach combines both dq and positive/negative sequence domain modelling, where a single wind turbine is modelled in the dq domain but the whole wind power plant connected to the weak grid is analysed in the positive/negative sequence domain. As the proposed modelling of the wind power plant is systematic and modular and based on the decoupled positive/negative sequence impedances, the application of the proposed methodology is relevant for transmission system operators (TSOs) to assess stability easily with a very low compactional burden. In addition, as the analytical dq impedance models of the single wind turbine are provided, the proposed methodology is an optimization design tool permitting wind turbine manufacturers to tune their converter control. As a case study, a 108 MW wind power plant connected to a weak grid was used to study its sensitivity to variations in network short-circuit level, X/R ratio and line series capacitor compensation (Xc/Xg).

Dual Brayton Cycle Gas Turbine Pressurized Fluidized Bed Combustion Power Plant Concept

1997 ◽  
Author(s):  
Xing L. Yan ◽  
Lawrence M. Lidsky
Keyword(s):  
Power Plant ◽  
Gas Turbine ◽  
Power Plants ◽  
Environmental Benefits ◽  
Brayton Cycle ◽  
Plant Design ◽  
Fluidized Bed Combustion ◽  
Electric Power Plants ◽  
Wide Range ◽  
Pressurized Fluidized Bed Combustion

High generating efficiency has compelling economic and environmental benefits for electric power plants. There are particular incentives to develop more efficient and cleaner coal-fired power plants, to permit use of the world’s most abundant and secure energy source. This paper presents a newly-conceived power plant design, the Dual Brayton Cycle Gas Turbine PFBC, that yields 45% net generating efficiency and fires on a wide range of fuels with minimum pollution, of which coal is a particularly intriguing target for its first application. The DBC-GT design allows power plants based on the state-of-the-art PFBC technology to achieve substantially higher generating efficiencies while simultaneously providing modern gas turbine and related heat exchanger technologies access to the large coal power generation market.

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