scholarly journals Multicriteria Assessment of Combined Heat and Power Systems

2018 ◽  
Vol 10 (9) ◽  
pp. 3240 ◽  
Author(s):  
Santoso Wibowo ◽  
Srimannarayana Grandhi

This paper presented a multicriteria assessment model for evaluating the performance of combined heat and power systems. Interval-valued intuitionistic fuzzy numbers were used for representing the subjective and imprecise assessments of the decision maker in evaluating the relative importance of the criteria, and the performance of individual combined heat and power systems. An effective algorithm was developed based on the concept of ideal solutions for calculating the overall performance index, for each combined heat and power system across all criteria. An example was presented to demonstrate the applicability of the multicriteria assessment model, for dealing with real world combined heat and power system performance evaluation problems.

Energies ◽  
2019 ◽  
Vol 12 (2) ◽  
pp. 274 ◽  
Author(s):  
Yun-Hyuk Choi ◽  
Yoon-Sung Cho

This paper proposes an advanced continuous voltage control method that implements multiple-point control to ensure peak power system performance. Most control schemes utilize generators to regulate the pilot point voltage of a control area. However, exact control of a single pilot point is difficult because of the influence of adjacent areas in a meshed power system. To address this challenge, the proposed method accesses multiple pilot points to mitigate the effects of the neighboring area. In simulations of the Korean power system, the proposed control scheme offered a considerable improvement in performance when compared with the conventional, currently implemented voltage control system.


2018 ◽  
Vol 7 (2.6) ◽  
pp. 130 ◽  
Author(s):  
Hayder O. Alwan ◽  
Noor M. Farhan

Outages and faults cause problems in interconnected power system with huge economic consequences in modern societies. In the power system blackouts, black start resources such as micro combined heat and power (CHP) systems and renewable energies, due to their self-start ability, are one of the solutions to restore power system as quickly as possible. In this paper, we propose a model for power system restoration considering CHP systems and renewable energy sources as being available in blackout states. We define a control variable representing a level of balance between the distance and importance of loads according to the importance and urgency of the affected customer. Dynamic power flow is considered in order to find feasible sequence and combination of loads for load restoration.


Author(s):  
Hanuman P. Agrawal ◽  
Hariom Bansal

Background: The power industry has been evolving continuously and influenced by a competitive deregulated market. The crucial demand to maximize the efficiency of the existing equipment requires it’s proper management. Flexible AC Transmission System (FACTS) are flexible devices, which provide dynamic control over the power system to cope with its dynamic nature. Methods: An extensive review is carried out on FACT devices covering its classification, importance, optimal placement and influence on the power systems. Results: In this paper, different techniques to identify the optimal location of placing FACT devices have been discussed and compared, as the placement of these devices in the power system is of utmost importance for its efficiency. Conclusion: This paper summarizes techniques available for optimal placement of FACTS devices in order to improve power system performance. It will serve as a ready reference for the future researchers in this field and help them in selecting the proper devices to carry out their work.


Author(s):  
Mauro Scagliotti ◽  
Carmen Valli

Extensive residential demonstration programs and the needs for innovative and reliable back up power systems are driving the development and diffusion of small (<10 kWe) stationary fuel cell power systems. Low temperature polymer electrolyte fuel cell (PEFC) power systems are particularly suitable for back up and UPS applications due to short start up times, whereas for small cogenerative residential applications both PEFC and solid oxide fuel cells (SOFCs) are emerging as promising technologies. The technical and economical viabilities of fuel cell based systems have been already demonstrated for a few niche applications such as back up system with high autonomy. Nevertheless fuel cell technologies are not yet mature. Durability and reliability are of great concern and have to be specifically addressed. Real world experiences and extensive laboratory testing are paramount for the development of reliable products, as well as to harmonize and refine codes and standards required for the market entry. This paper presents and discusses the results of a 3 year experience on commercial PEFC 1 kWe units. Basic characterization, cycling, and steady state endurance testing data are analyzed herein with a focus on power system performance, reliability, and degradation issues. End user and system integrator testing approaches were applied. Power system response to load demand and electrical efficiency were measured following as much as possible the prescriptions of codes and standards. The influences of operating and environmental conditions on system efficiency were investigated as well. Positive results were achieved and, in particular, system availability resulted extremely high. Steady state long term endurance tests evidenced, however, critical durability and safety issues to be improved.


2022 ◽  
Vol 28 (1) ◽  
pp. 52-64
Author(s):  
Truska Khalid Mohammed Salih ◽  
Zozan Saadallah Hussain ◽  
Firas Saaduldeen Ahmed

Nowadays power systems are huge networks that consist of electrical energy sources, static and lumped load components, connected over long distances by A.C. transmission lines. Voltage improvement is an important aspect of the power system. If the issue is not dealt with properly, may lead to voltage collapse.  In this paper, HVDC links/bipolar connections were inserted in a power system in order to improve the voltage profile. The load flow was simulated by Electrical Transient Analyzer Program (ETAP.16) program in which Newton- Raphson method is used. The load flow simulation studies show a significant enhancement of the power system performance after applying HVDC links on Kurdistan power systems. The bus voltages are significantly increased after connecting High Voltage Direct Current.


Author(s):  
K Mills ◽  
J Xiong ◽  
X Liu ◽  
P Venkatesh

Future warship power systems may be subject to pulsed loads manifesting through emergent combat systems such as directed energy weapons, associated sensors and electronic warfare equipment.  The integration of combat system loads with the ship’s power system means that performance becomes intrinsically linked to combat effectiveness.  Hence, understanding the capability of the power system to service such loads is vital in ensuring the operator’s ability to fight the ship. This paper describes the challenge of pulse load integration from the perspective of the power system design authority.  Modelling and simulation has been employed to study the electrical response of a representative power system when subject to a range pulse load characteristics.  Subsequently, the effects of pulse loading are reviewed in terms of impact upon the prime mover. It is concluded that whilst electrical supply performance can be maintained within allowable power quality limits as defined by STANAG 1008, the mechanical effects can be to the detriment of engine life, highlighting key recommendations to understand both electrical and mechanical performance envelope in design for integration. 


Energies ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 4484 ◽  
Author(s):  
Shifei Zhao ◽  
Weishu Wang ◽  
Zhihua Ge

High back-pressure technology is a promising method for the waste heat recovery of exhaust steams in combined heat and power systems. In this research, a 300 MW coal-fired subcritical combined heat and power system was selected as the reference system, and modeled in EBSILON professional. Then, energy-based and exergy-based performances of the high back-pressure system and traditional combined heat and power system were compared under full operating conditions. Moreover, a novel exergy-based evaluation method, which considers the energy level of the heating supply, was proposed and applied to evaluate the two systems. Results show that: In design conditions, both the heating capacity and power output of the high back-pressure system were higher than those of the extraction condensing system, which led to 17.67% and 33.21% increments of the gross thermal efficiency and generation efficiency, respectively. Compared with the extraction condensing system, the exergy efficiencies of the high back-pressure system were 7.04–8.21% higher. According to the novel exergy-based evaluation, the exergy efficiencies for the generation of the high back-pressure system and extraction condensing system were 46.48% and 41.22%, respectively. This paper provides references for the thermodynamic performance evaluation of the combined heat and power system.


Energies ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2493 ◽  
Author(s):  
Xiuyun Wang ◽  
Shaoxin Chen ◽  
Yibing Zhou ◽  
Jian Wang ◽  
Yang Cui

With the rapid development of wind power generation and photovoltaic power generation, the phenomenon of wind and solar abandoning becomes more and more serious in the operation of power systems, and the microgrid is a new operating mode of power systems which provides a new consumption mode for wind power generation. With the increasingly close connection among energy resources and people’s increasing awareness of environmental protection, this paper establishes a microgrid optimal scheduling model with a combined heat and power system, in consideration of environmental costs. This model aims at the lowest comprehensive cost, at the same time taking into account the emission reductions of SO2 and NOx, considering the cost of power generated by the micro-generator, environmental cost, the related cost of battery, operation and maintenance cost of wind power, and photovoltaic power generation. The related constraints of thermal balance and power balance are also considered during microgrid system operation. The established model is solved with an improved particle swarm algorithm. At last, taking a microgrid system as an example, the validity and reliability of the proposed model are verified.


2020 ◽  
Author(s):  
Gilles Mpembele ◽  
Jonathan Kimball

<div>The analysis of power system dynamics is usually conducted using traditional models based on the standard nonlinear differential algebraic equations (DAEs). In general, solutions to these equations can be obtained using numerical methods such as the Monte Carlo simulations. The use of methods based on the Stochastic Hybrid System (SHS) framework for power systems subject to stochastic behavior is relatively new. These methods have been successfully applied to power systems subjected to</div><div>stochastic inputs. This study discusses a class of SHSs referred to as Markov Jump Linear Systems (MJLSs), in which the entire dynamic system is jumping between distinct operating points, with different local small-signal dynamics. The numerical application is based on the analysis of the IEEE 37-bus power system switching between grid-tied and standalone operating modes. The Ordinary Differential Equations (ODEs) representing the evolution of the conditional moments are derived and a matrix representation of the system is developed. Results are compared to the averaged Monte Carlo simulation. The MJLS approach was found to have a key advantage of being far less computational expensive.</div>


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