Home
>
Journals & magazines
>
IEE Proceedings - Generation, Transmission and Di...
>
Volume 145
Issue 5
IEE Proceedings - Generation, Transmission and Distribution
Volume 145, Issue 5, September 1998
Volumes & issues:
Volume 145, Issue 5
September 1998
-
- Author(s): N.R. Watson and G.D. Irwin
- Source: IEE Proceedings - Generation, Transmission and Distribution, Volume 145, Issue 5, p. 481 –486
- DOI: 10.1049/ip-gtd:19982173
- Type: Article
- + Show details - Hide details
-
p.
481
–486
(6)
For electromagnetic transient simulations the method of substituting the trapezoidal integrator, developed by Dommel, is generally applied. The trapezoidal rule is based on a truncated Taylor series and therefore contains truncation errors. These truncation errors cause numerical oscillations when the time step is large relative to some of the time constants in the network. This leaves the user unsure whether observed oscillations are numerical or true artefacts of the system simulated. Various techniques have been developed to reduce the numerical oscillations, each with strengths and drawbacks. An exponential form of the difference equation is developed, using root-matching techniques and demonstrated on a simplified power system. This technique eliminates the truncation error and provides highly efficient and accurate time domain regardless of the time step used. This exponential form of difference equation generates a solution at each time point that is exact for the step response and a good approximation for an arbitrary forcing function. - Author(s): P.G. Barbosa ; L.G.B. Rolim ; E.H. Watanabe ; R. Hanitsch
- Source: IEE Proceedings - Generation, Transmission and Distribution, Volume 145, Issue 5, p. 487 –492
- DOI: 10.1049/ip-gtd:19982174
- Type: Article
- + Show details - Hide details
-
p.
487
–492
(6)
The paper presents the modelling, analysis and design of a pulse width modulation voltage source inverter (PWM-VSI) to be connected between a DC source, which is supplied from a photovoltaic (PV) array and the AC grid. The control algorithm of the PWM-VSI applies the concepts of the instantaneous p-q (real-imaginary) power theory. The objective is to show that, with an adequate control, the converter can transfer the DC energy from PV array and improve the power factor (and the power quality) of the electrical system. Some design considerations are also discussed. A digital simulation and measurements on a small prototype model verified the feasibility of the proposed control method. - Author(s): R. Mihalič
- Source: IEE Proceedings - Generation, Transmission and Distribution, Volume 145, Issue 5, p. 493 –498
- DOI: 10.1049/ip-gtd:19982175
- Type: Article
- + Show details - Hide details
-
p.
493
–498
(6)
The basic features of controllable reactive series elements (CRSE) (i.e. controllable series compensation (CSC) and a static synchronous series compensator (SSSC)) for system power flow control are presented. Mathematical models of CRSE, including a simplified transmission system model, have been developed. Based on this, the CRSE impact on a longitudinal transmission system was studied. The physical background of the basic differences between a CSC and an SSSC in terms of power flow control has been presented. According to theoretical considerations, from the point of view of power flow control capability, SSSC is superior to CSC, especially at low transmission angles. Therefore SSSC seems to be suitable in situations where power flow needs to be controlled in short lines or in light-load conditions. - Author(s): M.R. Irving and C.N. Macqueen
- Source: IEE Proceedings - Generation, Transmission and Distribution, Volume 145, Issue 5, p. 499 –504
- DOI: 10.1049/ip-gtd:19982176
- Type: Article
- + Show details - Hide details
-
p.
499
–504
(6)
A new mathematical model is proposed which allows distribution network loads to be estimated using the available information from metering and other data sources. The application of this model offers a compromise between conventional load allocation methods and network state estimation. A novel approach to the modelling of current magnitude measurements is introduced. The problem is formulated as a weighted least absolute values estimation problem which is solved numerically using weighted least squares with an iterative reweighting scheme. The nonlinear effect of power losses is accounted for by applying a Newton–Raphson approach. Alternative sparse matrix solution techniques are compared and a robust and computationally efficient approach is described which is suitable for online applications. - Author(s): A.A.P. Lerm ; F.A.B. Lemos ; A.S. e Silva ; M.R. Irving
- Source: IEE Proceedings - Generation, Transmission and Distribution, Volume 145, Issue 5, p. 505 –510
- DOI: 10.1049/ip-gtd:19982177
- Type: Article
- + Show details - Hide details
-
p.
505
–510
(6)
The work presents new methodologies in order to represent with more accuracy the hard limits of voltage regulators in the modal analysis. These hard limits are treated in the linearisation process by Taylor and Power Series and hyperbolic functions. The procedures required to adapt a conventional load flow in order to include a more realistic behaviour of generators in the determination of initial conditions are described. A methodology is presented which considers the dependence of generator reactive power limits on the operating conditions. Such procedures aim at a more realistic analysis of the power system especially at high loadings. Results are presented for a system which validate the proposed methodologies. - Author(s): Z. Saad-Saoud ; M.L. Lisboa ; J.B. Ekanayake ; N. Jenkins ; G. Strbac
- Source: IEE Proceedings - Generation, Transmission and Distribution, Volume 145, Issue 5, p. 511 –516
- DOI: 10.1049/ip-gtd:19982178
- Type: Article
- + Show details - Hide details
-
p.
511
–516
(6)
Effective reactive power control in distribution networks can have an important influence on the level of embedded generation that is acceptable and on the costs of its connection. A comprehensive study was undertaken to investigate how STATCOMs could be used with fixed-speed wind turbines, which use induction generators, to improve both the steady-state and dynamic impact of a wind farm on the network. An optimal power flow model based on loss minimisation was developed and used to show that operation of a wind farm at unity power factor is unlikely to allow maximum penetration of wind energy into a weak distribution circuit. The results of the electromagnetic simulations showed that the use of a STATCOM improves the steady-state stability limits of the network. They also showed that the use of a STATCOM with an appropriately designed control strategy can prevent damaging overvoltages that may occur under islanding conditions. The results also demonstrated that a STATCOM can be used to mitigate voltage fluctuations at blade passing frequency, which may occur if the rotors of a number of wind turbines fall into synchronism. - Author(s): M. Moghavvemi and O. Faruque
- Source: IEE Proceedings - Generation, Transmission and Distribution, Volume 145, Issue 5, p. 517 –524
- DOI: 10.1049/ip-gtd:19982179
- Type: Article
- + Show details - Hide details
-
p.
517
–524
(8)
The tendency towards maximising economic benefits has led power systems utilities to run close to the limits of stable operation. This has necessitated the study of the stressed situation of the power system network to accomplish efficient energy management without losing its reliability. On-line monitoring of power system stability has become a vital factor for electric utilities. An effective method for real-time monitoring of system status and thus voltage collapse prediction is described. The proposed technique investigates each line of the system through calculating an indicator that varies from 0 (no load condition) to 1 (maximum permissible loading condition). The basic concept of maximum power transfer through a line is utilised. The proposed contingency evaluation technique is applied on the IEEE 24 bus and IEEE 6 bus reliability test system and is found to be accurate in assessing the stressful status of the lines. - Author(s): S.S. Lee and J.K. Park
- Source: IEE Proceedings - Generation, Transmission and Distribution, Volume 145, Issue 5, p. 525 –530
- DOI: 10.1049/ip-gtd:19982180
- Type: Article
- + Show details - Hide details
-
p.
525
–530
(6)
In the paper, to design a simpler and more economical observer-based controller, and to solve the problem associated with the unmeasurable state variables in the conventional VSC, a reduced-order (n – m) observer-based variable structure controller (ROOVSC) is proposed and applied to a power system stabiliser (PSS). This ROOVSPSS is obtained by combining the variable structure control (VSC) with a reduced-order observer (ROO): the state estimator by the ROO and the controller by the VSC, which eliminates the need to measure all the state variables in the conventional VSC-PSS. The simulation results are shown by comparison of the ROOPSS with the proposed ROOVSPSS under normal and heavy load operations. - Author(s): Y. Liao and S. Elangovan
- Source: IEE Proceedings - Generation, Transmission and Distribution, Volume 145, Issue 5, p. 531 –536
- DOI: 10.1049/ip-gtd:19982181
- Type: Article
- + Show details - Hide details
-
p.
531
–536
(6)
The paper proposes a new digital distance relaying algorithm for first-zone protection for parallel transmission lines. The new method uses data from one end of the protected parallel lines to calculate the fault distance. It is shown that the new method is independent of fault resistance, remote infeed and source impedances. Extensive simulation studies using EMTP have verified that this approach can obtain a highly accurate fault distance estimation within one cycle after fault inception and hence is very much suitable for digital distance protection for parallel lines. Applications of this method for fault location are also presented. - Author(s): J. Machowski ; J.W. Bialek ; S. Robak ; J.R. Bumby
- Source: IEE Proceedings - Generation, Transmission and Distribution, Volume 145, Issue 5, p. 537 –546
- DOI: 10.1049/ip-gtd:19982182
- Type: Article
- + Show details - Hide details
-
p.
537
–546
(10)
An optimal excitation control strategy for a synchronous generator is derived using Lyapunov's direct method and the nonlinear system equations. The control strategy requires neither phase compensation nor wash-out circuits characteristic of standard power system stabilisers (PSS). By using a nonlinear system model, the control strategy is optimal over a wide range of rotor angle and swing frequency changes. The excitation control system required to implement the control strategy is hierarchical and has a different structure to the traditional excitation control system with PSS. In the proposed structure a primary controller damps quickly any power swings using the synchronous EMF as the feedback signal. A secondary controller maintains constant generator voltage by adjusting the reference value of the synchronous EMF fed to the primary controller to that required by the actual operating conditions. The proposed excitation control system has been tested on a single generator-infinite busbar system with the simulation results showing excellent damping of power swings over a wide range of operating conditions whilst retaining good voltage control. - Author(s): S.C. Bell ; S.D.J. McArthur ; J.R. McDonald ; G.M. Burt ; R. Mather ; T. Cumming
- Source: IEE Proceedings - Generation, Transmission and Distribution, Volume 145, Issue 5, p. 547 –552
- DOI: 10.1049/ip-gtd:19982183
- Type: Article
- + Show details - Hide details
-
p.
547
–552
(6)
Following a power system fault, protection engineers have to analyse the protection scheme activity to ensure correct operation. To aid them in this task, data gathering systems are increasingly being fitted to the power system. However, during extreme operating conditions the volume of data made available by these systems can be overwhelming. To help overcome this, knowledge-based systems have been developed and installed at ScottishPower's corporate headquarters to extract the relevant ‘information’ from the Supervisory Control and Data Acquisition (SCADA) system ‘data’. The paper reports on the next stage of decision support for the protection engineers which builds upon the diagnosis provided by the knowledge-based systems. This enhanced support is provided by a model-based diagnostic system which provides automatic analysis of the available fault recorder data. This system utilises the most appropriate techniques employed by existing model-based diagnostic systems. A novel approach for handling tolerances associated with the operating times of protection scheme components is introduced, thus enabling modelling and measurement inaccuracies to be dealt with. - Author(s): X.R. Chen ; N.C. Pahalawaththa ; U.D. Annakkage ; C.S. Kumble
- Source: IEE Proceedings - Generation, Transmission and Distribution, Volume 145, Issue 5, p. 553 –558
- DOI: 10.1049/ip-gtd:19982184
- Type: Article
- + Show details - Hide details
-
p.
553
–558
(6)
A novel method for the design of output feedback controllers for thyristor controlled series compensators (TCSCs) in a meshed power system is developed in the paper. The selection of the output feedback gains for the TCSC controllers is formulated as an optimisation problem and the simulated annealing (SA) algorithm is used to find the solution. Using this method, the conflicting design objectives, such as the improvement in the damping of the critical modes, any deterioration of the damping of the non critical modes and the saturation of the controller actuators, can be simultaneously considered. It is also shown that the proposed SA algorithm can be used to design robust controllers which satisfy the required performance criteria over several operating conditions. The proposed control scheme can be easily implemented as only the measurable signals local to each TCSC location are used to control the TCSCs (decentralised control). - Author(s): Q.N. Dinh ; J. Arrillaga ; B.C. Smith
- Source: IEE Proceedings - Generation, Transmission and Distribution, Volume 145, Issue 5, p. 559 –565
- DOI: 10.1049/ip-gtd:19981978
- Type: Article
- + Show details - Hide details
-
p.
559
–565
(7)
A new twelve-pulse unit connection model is formulated and solved in the harmonic domain. The model takes into account the effects of generator saliency and saturation, interaction of the converter with the DC system, and variation in the firing and end of commutation angles caused by AC voltage and DC current harmonics. The reactive power control by generator excitation in the absence of converter transformer on-load tap-changers is also modelled. The solution of a test system is validated by means of time domain simulations. - Author(s): J.O. Kim and C. Singh
- Source: IEE Proceedings - Generation, Transmission and Distribution, Volume 145, Issue 5, p. 566 –572
- DOI: 10.1049/ip-gtd:19982185
- Type: Article
- + Show details - Hide details
-
p.
566
–572
(7)
The paper presents a generalised expansion method using a gamma distribution as a useful tool for the approximation of capacity outage probability distribution of a generation system. The well known Gram–Charlier expansion and Legendre series are briefly reviewed and compared with the generalised expansion using a sample system IEEE-RTS (reliability test system). The results show that the generalised expansion with a composite of gamma distributions is more accurate and stable than the Gram–Charlier expansion and Legendre series as higher order expansion terms are included. - Author(s): R.B. Prada and L.J. Souza
- Source: IEE Proceedings - Generation, Transmission and Distribution, Volume 145, Issue 5, p. 573 –577
- DOI: 10.1049/ip-gtd:19982186
- Type: Article
- + Show details - Hide details
-
p.
573
–577
(5)
The loading condition of distribution systems is assessed with respect to voltage stability as well as to thermal limit. Real networks of a distribution utility of Brazil are used in the tests performed. Results show that the maximum loading may be limited by voltage stability rather than by thermal limit. The paper shows the necessity of considering voltage stability as a new constraint on the operational loading of electrical energy distribution feeders, including the connection of new consumers. The voltage stability constraint should be considered in studies concerning distribution systems expansion. The new planning constraint may avoid the building of new lines and transformers which could never be fully used in systems already stressed by voltage stability. - Author(s): J. Szafran and W. Rebizant
- Source: IEE Proceedings - Generation, Transmission and Distribution, Volume 145, Issue 5, p. 578 –582
- DOI: 10.1049/ip-gtd:19982187
- Type: Article
- + Show details - Hide details
-
p.
578
–582
(5)
A new algorithm of power system frequency estimation is presented. The algorithm applies orthogonal signal components obtained with use of two orthogonal FIR filters. The essential property of the algorithm presented is its outstanding immunity to both signal orthogonal component magnitudes and FIR filter gains variations which ensures 1.5 mHz accuracy of estimation over typical (±2 Hz) range of measured frequency deviation. The results of the algorithm simulation tests using the EMTP software package are also included. It was confirmed that the algorithm dynamics are good enough to track power system frequency even under transient conditions. - Author(s): C.S. Chang and W. Fu
- Source: IEE Proceedings - Generation, Transmission and Distribution, Volume 145, Issue 5, p. 583 –591
- DOI: 10.1049/ip-gtd:19981997
- Type: Article
- + Show details - Hide details
-
p.
583
–591
(9)
A new stochastic formulation of multiobjective optimisation for combined heat and power system dispatch is presented. Both the power and heat demands are treated as random variables. The three objective functions to be minimised are: the total generation cost, the expected power generation deviation and the expected heat generation deviation. As these objectives are in conflict with each other, only a non-inferior solution can be reached. The goal attainment method is used to solve this multiobjective optimisation problem by assuming that the decision-maker (DM) has desired a certain goal for each of these objectives. Very often, the DM finds it difficult to define the relative importance or a merit function among improving individual objectives and reducing constraint violations. A fuzzy decision index is proposed here to provide the best-compromise solution among all objectives and constraints, and a means of maximising the most underachieved objective. A genetic algorithm approach is also proposed to help the DM to search for such a solution mathematically. Application results of the method to a seven-generator sample system are presented. - Author(s): M.R. Montakhab and R.N. Adams
- Source: IEE Proceedings - Generation, Transmission and Distribution, Volume 145, Issue 5, p. 592 –596
- DOI: 10.1049/ip-gtd:19982188
- Type: Article
- + Show details - Hide details
-
p.
592
–596
(5)
The task of fault diagnosis on the distribution networks operating at 11 kV and lower voltages is very different from the higher voltage levels because very little telemetered data is available and knowledge of a fault occurrence often depends on customers complaining of loss of supply. Unfortunately, the connectivity of customers to the network is not normally available on geographic information systems (GIS), so connectivity is indirectly established through post codes. A novel kind of object oriented blackboard architecture using deep and shallow knowledge has been developed. The notion of object-oriented active databases has also been introduced. The intelligent system developed can assist the control engineer in diagnosing the fault quickly to ameliorate the immediate effects of the fault. The special feature of this research is that the developed architecture is suitable for any fault diagnosis situation where information of the system is incomplete and is accrued over a period of time. Partial solutions are obtained as the first piece of information is received and these partial solutions are improved as further information is received. - Author(s): S.-J. Huang ; J.-C. Wu ; H.-L. Jou
- Source: IEE Proceedings - Generation, Transmission and Distribution, Volume 145, Issue 5, p. 597 –603
- DOI: 10.1049/ip-gtd:19982189
- Type: Article
- + Show details - Hide details
-
p.
597
–603
(7)
A parallel active-power conditioner is proposed for electric-power-quality improvement. In the proposed conditioner, a three-phase voltage of high quality can be promised under various nonideal utility conditions, including utility undervoltage, overvoltage, outage, pollution and unbalance scenarios. A systematic procedure for the design of active-power conditioners is also provided. Test results have demonstrated the effectiveness of the method in improving electric-power quality on the load side. This approach also has the potential to be extended or integrated to other circuit designs. - Author(s): A.I. Megahed and O.P. Malik
- Source: IEE Proceedings - Generation, Transmission and Distribution, Volume 145, Issue 5, p. 604 –610
- DOI: 10.1049/ip-gtd:19982190
- Type: Article
- + Show details - Hide details
-
p.
604
–610
(7)
Along with the development of electric power industry, accurate analysis of faulted generators becomes more and more important. The paper presents a method for simulating internal faults in synchronous generators, consisting of a single path per phase, using direct phase quantities. Simulation results showing the fault currents, during single phase to ground faults and two phase to ground faults, are compared with actual fault currents to verify the proposed method. - Author(s): R.N. Allan ; R. Li ; M.M. Elkateb
- Source: IEE Proceedings - Generation, Transmission and Distribution, Volume 145, Issue 5, p. 611 –615
- DOI: 10.1049/ip-gtd:19982191
- Type: Article
- + Show details - Hide details
-
p.
611
–615
(5)
Power system planning inherently needs to consider all aspects of how a power system may be planned and operated to provide a reliable and economic supply of electrical energy. This includes the need to simulate generation production, particularly the appropriate co-ordination between thermal and hydrogeneration. One of the most difficult features of this is the incorporation of limited-energy pumped-storage hydrogeneration within such simulations. This paper describes a new approach for incorporating pumped-storage units using sequential Monte Carlo simulation. The scheduling is defined as a constrained optimisation problem using a network flow algorithm. The application and benefits of the proposed model are demonstrated using the IEEE reliability test system. - Author(s): L.L. Lai ; A.G. Sichanie ; B.J. Gwyn
- Source: IEE Proceedings - Generation, Transmission and Distribution, Volume 145, Issue 5, p. 616 –620
- DOI: 10.1049/ip-gtd:19982192
- Type: Article
- + Show details - Hide details
-
p.
616
–620
(5)
The paper proposes an application of evolutionary programming (EP) to fault-section estimation in power systems. Several techniques have been employed to solve this problem so far. A genetic algorithm (GA) has been reported to be one of these techniques. In order to measure the efficiency of EP and make comparisons, a GA has also been used to solve the same problem. Different parameters which affect the EP convergence have been investigated. Two object-oriented software codes have been developed to implement the algorithms. A sample power system is used to examine the algorithms. It shows that EP is superior to the GA for the type of coding strategy and evolution as defined for the GA.
Electromagnetic transient simulation of power systems using root-matching techniques
Control strategy for grid-connected DC-AC converters with load power factor correction
Power flow control with controllable reactive series elements
Robust algorithm for load estimation in distribution networks
Voltage stability assessment with inclusion of hard limits
Application of STATCOMs to wind farms
Real-time contingency evaluation and ranking technique
Design of reduced-order observer-based variable structure power system stabiliser for unmeasurable state variables
Digital distance relaying algorithm for first-zone protection for parallel transmission lines
Excitation control system for use with synchronous generators
Model-based analysis of protection system performance
Design of decentralised output feedback TCSC damping controllers by using simulated annealing
Steady-state model of direct connected generator–HVdc converter units in the harmonic domain
Comparative study of continuous distribution models for power system reliability evaluation
Voltage stability and thermal limit: Constraints on the maximum loading of electrical energy distribution feeders
Power system frequency estimation
Stochastic multiobjective generation dispatch of combined heat and power systems
Intelligent system for fault diagnosis on low voltage distribution networks
Electric-power-quality improvement using parallel active-power conditioners
Synchronous generator internal fault computation and experimental verification
Modelling of pumped-storage generation in sequential Monte Carlo production simulation
Comparison between evolutionary programming and a genetic algorithm for fault-section estimation
Most viewed content for this Journal
Article
content/journals/ip-gtd
Journal
5
Most cited content for this Journal
We currently have no most cited data available for this content.