No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Gennerator internal fault modeling and analysis based on one-machine infinite-bus power system
Abstract
This paper presents the generator's internal fault modeling and analysis based on the one-machine infinite-bus power system for the simulation of internal faults in a synchronous generator. The model applied is a low-order synchronous generator model, and is based on the so-called fourth-order representation with the mechanical mode from the second-order system and the electrical mode from the second-order system. The test cases for internal faults demonstrates the output waveforms for id, iq, vd, vq, ω, Efd, Vt, Te, ia, ib, ic, va, vb, and vc using the MATLAB tool. Furthermore, the fault perturbations for internal windings and for an exciter terminal are also carried out and are compared by the results of four cases of simulations.
This paper presents a hydro and gas turbine blackout restoration strategies for the South Korean power system. A restorative procedure has been assigned by the KPX (Korea Power Exchange) in the case of blackouts occurring throughout all areas in South Korea. The power system of the Korea Electric Power Corporation (KEPCO) was divided into power grids by seven subsystems. The power after the blackout was reenergized to the power restoration line (PRL) through a black-start generator (BSG). The additional power in a power system can be effectively done more and more by adding a gas turbine generation system for the conventional hydro power plant. The results of the analysis were simulated, which was illustrated using the PSCAD/EMTDC tool.
Generator protection device has to detects an internal fault conditions in generator and abnormal operating conditions must be due to the hazards. Loss of excitation may cause generator itself failure as well as serious operating problem in power system, and then requires an appropriate response of generator protection device. Details modeling of generator control system and analysis of transient states in generator are important for optimal operation in power plants. In addition, the fault simulation data are also used for testing the characteristics of IED. In this paper, the hydro generator control system using PSCAD/EMTDC, visual simulation for power systems, was modeled. The generator control system which is composed of generator, turbine, exciter, governor was implemented. The parameters of generator control system model were obtained from field power plant. Loss of excitation simulations were performed while varying the fixed load. Several signals analysis were also performed so as to analyze transients phenomena.
Large generator of power plant is very important. In order to protect large generator from faults, digital protective relay or IED is required. However, all protective relays for generators of the domestic power plant are operated by foreign products. And now, for technological independence from foreign and improvement of import substitution effect, IEDs using domestic technology are being developed. To evaluate performance of developing next-generation power devices, the study of the dynamic characteristics of the power plant, generator system modeling, fault simulation and analysis, should be considered. Specially, To obtain IEEE Standards COMTRADE format for relay operation test, generator system modeling and fault simulation using PSCAD/EMTDC tools must be preceded. Until now, a complete modeling of generator internal windings and fault simulation techniques dose not exist. In this paper, for evaluation performance of relay elements of developing IED, the generator system modeling and various faults simulation using PSCAD/EMTDC tools were performed. And then, the various transient phenomena through obtained relaying signal of developed modeling were analyzed.
A large generator is an important role in transferring an electric power to power system. The IEDs of large generator often use microprocessor technology to obtain a digital relay system with a wide range of measuring, protection, control, monitoring, and communication functions. However, all generator protection and control systems in Korea imported from abroad and are being operated. In order to reduce the large expense and improve the reliable operation, development of generator protection and control system by domestic technology is required. This paper deals with the design of the IED of generator protection panel for development of generator protection and control system. The major emphasis of the paper will be on the description of hardware and signal processing test results and measurement accuracy of the prototype IED. By developing of generator IED based on DSP and microprocessor, replacement of the generator protection panel imports are expected to be effective.
This report describes and presents the results of continued efforts of New Mexico State University (NMSU) under LANL Subcontract 9-X58-9569R-1 to enable the feasible assessment of the anticipated effects of large Laboratory pulsed loads and other expected operating conditions upon the electric power supply network to the Laboratory. A primary objective of NMSU's total research effort in this area has been the development of procedures for estimating the impacts of proposed pulsed and steady-state loads upon the Los Alamos National Laboratory electric power system and, conversely, the specification of maximum allowable loadings of particular type and frequency content.
Starting with the basic assumption of no saturation or hysteresis, and with distribution of armature phase m. m. f. effectively sinusoidal as far as regards phenomena dependent upon rotor position, general formulas are developed for current, voltage, power, and torque under steady and transient load conditions. Special detailed formulas are also developed which permit the determination of current and torque on three-phase short circuit, during starting, and when only small deviations from an average operating angle are involved. In addition, new and more accurate equivalent circuits are developed for synchronous and asynchronous machines operating in parallel, and the domain of validity of such circuits is established. Throughout, the treatment has been generalized to include salient poles and an arbitrary number of rotor circuits. The analysis is thus adapted to machines equipped with field pole collars, or with amortisseur windings of any arbitrary construction. It is proposed to continue the analysis in a subsequent paper.
The calculation of synchronous machine parameters from sudden short-circuit measurements has been subject to unnecessary assumptions and approximations. The authors describe the nature of these approximations and a procedure to remove them, and they illustrate how a new philosophy for problem formulation and solution using backsolving programs can simplify and clarify the solution process. They introduce a method of calculating eigenvalues that is based on a generalization of the eigenvalue problem. Approximations are unnecessary, and the formulation is much cleaner than in previous efforts. Even for large values of armature resistance, the time constants are correctly computed, since the coupling between axes is considered.
This paper discusses a technique for partitioning the stator
windings of large synchronous machines, for application to internal
fault analysis, and determining corresponding winding inductances. The
method employs a direct phase representation, which is shown to reduce
to the classical phase representation when the partitioned windings are
collapsed
For pt.I see ibid., vol.15, no.4, p.376-9 (2000). This paper
applies techniques for analyzing internal phase and ground faults in the
stator windings of large synchronous machines. A variety of internal
fault conditions are considered, with results for a 75% ground fault
presented, along with comprehensive data for a test machine. The
methodology is validated by comparison with results obtained from
independent finite element analyses
This paper discusses the construction of a mathematical model of a
large synchronous machine suitable for analyzing internal phase and
ground faults in stator windings. The method employs a direct phase
representation, and uses conventional, and readily available, machine
data. The methodology was validated by comparison with results obtained
from independent finite element analyses
An internal fault in the armature winding of a synchronous
generator occurs due to the breakdown of the winding insulation. In this
paper, a method for simulating internal faults in synchronous
generators, using direct phase quantities, is described. Simulation
results showing the fault currents, during a single phase to ground
fault and a two phase to ground fault, are presented
A new synchronous machine model is presented which is readily
implemented in either circuit-based or differential-equation-based
simulation programs. This model is well suited for the simulation and
analysis of synchronous machine-power converter systems. It is based
upon standard representations and no approximations are made in its
derivation. However, the numerical implementation is shown to be
significantly more efficient. An example is provided which demonstrates
a 1700% increase in simulation speed with no observable loss in
accuracy. The model includes provisions for an arbitrary number of
damper or rotor windings and may be easily modified to represent
synchronous or induction machines with an arbitrary number of stator
phases
This paper presents the results of a time-domain identification
procedure to estimate the linear parameters of a 15 kVA salient-pole
synchronous machine at standstill. A step voltage input test is
performed, and the parameters of the time constant models and equivalent
circuit models are estimated. The maximum likelihood algorithm is used
for the estimation, and the best-fit model is selected from a set of
increasing order models. The initialization values for the parameters to
be estimated are determined from the operational inductances derived
directly from the measured time domain data. The simulated equivalent
circuit model response is validated against the measured standstill time
domain and frequency domain data. In addition, simulation of the model
response to an on-line small disturbance test is compared to the
measured dynamic response
A method is presented for determining the characteristic
quantities and model parameters from the given frequency responses x
<sub>d</sub>( js ), x <sub>q</sub>( js ). The
curves of values measured on a large turbogenerator at standstill are
used as an example. The characteristic values and model parameters are
determined for various models (with four, three, and two rotor circuits
in each axis) and are compared with the results of short-circuit tests
and with advanced calculations
This paper re-examines the three synchronous machine modeling techniques used for electromagnetic transient simulations, namely, the qd model, phase-domain model, and voltage-behind-reactance model. Contrary to the claims made in several recent publications, these models are all equivalent in the continuous-time domain, as their corresponding differential equations can be algebraically derived from each other. Computer studies of a single-machine infinite-bus system demonstrate that all of these models can be used for unsymmetrical operation of power systems. The conversion of machine parameters is also discussed and is shown to have some impact on simulation accuracy, which is acceptable for most cases. When the models are discretized and interfaced with an EMTP-type network solution, the voltage-behind-reactance model is shown to be the most accurate due to its advanced structure.
10. The output waveforms for the terminal voltage
- Fig
Fig. 10. The output waveforms for the terminal voltage (V t ).