EMTP Contactor Modeling for Load Modeling Studies (original) (raw)
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IEE Proceedings B Electric Power Applications, 1992
The paper investigates the dynamic representation of a group of induction motors by one or more equivalent motors for power system transient stability studies. Considering the fact that large induction motors constitute a large proportion of the total system load, and that the skineffect has a very strong effect on the performance of these machines, this effect is therefore included in the model. To enable the skin effect (deep bar effect) to be included, the stator and the rotor windings leakage reactances are separated and the core losses are ignored; and the equivalent machine is represented by seven electrical parameters instead of the conventional five parameters. A clear procedure is described on how to obtain the unknown electrical and the mechanical parameters of the equivalent machine. An efficient grouping (homogeneity) criteria is proposed to obtain subgroups in the case of a diversified group of induction machines connected to the same bus and a power system subjected to disturbances of various types. The accuracy of the equivalent model is verified by simulating its response to different types of disturbances and comparing the results with the sum of the responses of the individual machines. Excellent agreement is obtained between the response of the model and the sum of the responses of the individual machines. List of principal symbols Ti, = open circuit time constant, s H = inertia constant os = synchronous angular velocity of the shaft, rad/s X , = total standstill leakage reactance, R M,, = mutual inductance between the stator and rotor J Z = impedance, R q, = locked-rotor torque, Nm windings, H = shaft system inertia, kgm2 Paper 9027B (P l , Pg), first received 4th November 1991 and in revised form 2nd June 1992 The authors are with The University of Bahrain, College of Engineering, Department of Electrical Engineering, PO Box 33547, Isa Town, State of Bahrain
A Novel Parametric Model for AC Contactors
IEEE Transactions on Magnetics, 2000
This paper develops a robust and fast parametric model to describe the dynamic behavior of an ac contactor. The model solves simultaneously the mechanical and electromagnetic coupled differential equations that govern its dynamic response. It deals with the shading rings and takes into account the fringing flux. Data from simulations carried out by applying the presented parametric model are compared with experimental data, demonstrating the model's validity and effectiveness.
Sensitivity of AC Coil Contactors to Voltage Sags, Short Interruptions, and Undervoltage Transients
IEEE Transactions on Power Delivery, 2004
This paper discusses the sensitivity of ac coil contactors to voltage sags, short interruptions, and undervoltage transients on the basis of extensive test results. Existing standards and previously published work are reviewed, and a detailed description of the testing procedure used is presented. The following tests were performed: sensitivity to rectangular voltage sags with ideal and nonideal supply voltage, testing with two-stage voltage sags, and voltage sags which occur during starting of large motors, as well as testing against measured voltage sag. The importance of voltage sag characteristics besides magnitude and duration was also investigated. Generic sensitivity curves are proposed.
Impact of Building-Level Motor Protection on Power System Transient Behaviors
2018 IEEE Power & Energy Society General Meeting (PESGM), 2018
Protection strategies for transmission and distribution systems have been extensively investigated to facilitate better coordination of physical protection devices. A diverse range of functional motors with dedicated protection schemes are being used more and more in commercial, residential, and industrial buildings. This paper focuses on simulating several of the most popular protection schemes using the Electro-Magnetic Transient Program (EMTP) model for three-phase and single-phase induction motors in existing commercial buildings connected to typical distribution feeders. To investigate the behaviors of single-phase motors stalling, the actions of motor protection and reconnections, and the impacts of device-level protection on system-level dynamics, we imposed voltage depressions at the head of a feeder fully loaded with functional induction motors. Several distribution feeders are represented in a standard IEEE 39-bus transmission system to simulate fault-induced delayed volta...
Analysis of AC Contactor Model during Voltage Sag with Point-In-Wave of Initiation
Przeglad Elektrotechniczny
This paper presents the analysis of AC contactor model, its ride through capability and behaviour during voltage sag with point-in-wave of initiation using PSCAD/EMTDC simulation software. The ride-through capability curve is used to identify the sensitivity level in the AC contactor failure area. AC contactor simulation model were supplied with various type of voltage sag with point-in-wave of initiation. Simulation results are also validated with the ride through capability curve of the experimental results.
2014
Large scale production of the numerical protection relays for the induction motors offer a wide range of protection functions such as (ANSI codes are listed in parentheses): Directional phase overcurrent (67) and phase overcurrent (50/51) Directional earth fault (67N) and earth fault (50N/51N) Directional active overpower (32P) Phase undercurrent (37) Negative sequence / unbalance (46) Excessive starting time, locked rotor (48/51 LR) Thermal overload (49RMS) Setting this protection requires a detailed analysis of the characteristics of the motor. Also, the correct setting of the motor protection must take into account the characteristics of the supply power system, particularly, by the treatment of the neutral for power system. Several papers deal with this issue. The paper [2] presents a combined protection approach for induction motors. To achieve this, the current, voltage, speed and temperature values of the induction motor were measured with sensors and processed ...
2010 The 2nd International Conference on Computer and Automation Engineering (ICCAE), 2010
This paper presents the development of digital simulator tool for sensitivity analysis of ac contactor with respect to voltage sag characteristics. The simulator tool allows varying of the sag characteristics for the purpose of evaluating the behavior of ac contactor under very worst conditions of voltage sags. Describing voltage sag characteristics by their magnitude and duration only without consideration of other parameters is no longer suitable to fully assess the equipments sensitivity. Therefore, this paper presents the necessity to include the point-on-wave of sag initiation and phase shift of sag to explain the sensitivity of ac contactor during sags. From the simulation results, the ride through capability curve is constructed to identify ac contactor sensitivity levels. The curve has demonstrated a rather complex behavior of the ac contactor. By having a simulator tool, ac contactor analysis can be simulated for any type of configurations without having to perform laboratory experiments.
INDUCTION MOTOR DYNAMIC SIMULATION IN TRANSIENTS
INDUCTION MOTOR DYNAMIC SIMULATION DURING DISCONNECTION FROM THE MAIN POWER , 2021
With the technology development of Automatic Transfer switching systems in power plants, it is necessary to increase the knowledge of the transient phenomena related to the disconnection of induction machines and their behavior during the transitory phases, in order to correctly associate devices that can increase the reliability of the plant system and maintain the safety of switching operations.
1993
Electrical service faults and momentary voltage interruptioas are of growing " e m in process industries where individual sensitive equipment or controls can disrupt the entire plant. This paper uses dynamic simulations to predict the lowvoltage ride-through performance of three common motor and power source configurations. The objectives are to identify motor control and protection strategies that increase the motor's immunity to expected low-voltage events while pointing out specific problems and opportunities. Configurations include transfer of a group of motors from one power source to another, ride-through of a single motor during low-voltage events, and ride-through of a motor buffered by an adjustable-speed drive. Low-voltage conditions match those expected to occur due to faults in the utility power system with transformer connection considered.
DYNAMIC MODELING OF SINGLE-PHASE INDUCTION MOTOR LOADS
Single-phase induction machines are found in various appliances such as refrigerators, washing machines, driers, air conditioners, and fans. Large concentrations of single-phase induction motor loads such as air conditioners and other motorcompressor loads can adversely impact the dynamic performance of a power system.