6 Results for the search " Motor":
Author: h.gras
Type: Model
Downloaded: 429 times
Date: 2018-06-08
Vacuum Circuit breaker (VCB)
Description:
Three main characteristics of VCBs have been taken into account in the implemented model:
1. the chopping current value;
2. the cold withstand voltage characteristic (or cold gap breakdown v... see moreoltage);
3. the high frequency current quenching capability.
Ref: Transient Recovery Voltages in Vacuum Circuit Breakers Generated by the Interruption of Inrush Currents of Large Motors
A. Borghetti, F. Napolitano, C.A. Nucci, M. Paolone, M. Sultan, N. Tripaldi
Tag(s): Vacuum, circuit breaker, VCB,
Author: n.sene
Type: Publication
Date: 2015-04-01
Transient recovery voltages in vacuum circuit breakers generated by the early-interruption of the inrush current of large motors
Description:
The switching of medium voltage electrical motors is typically realized by means of vacuum circuit breakers (VCBs) essentially in view of their elevated number of switching cycles. As known, switching... see more of VCBs generates important transient recovery voltages (TRVs)
that need to be properly evaluated in both VCB sizing and in the power system insulation coordination. As large medium voltage electrical motors are installed into plants typically controlled by means of Supervisory Control And Data Acquisition (SCADA) systems,
maneuvers that involve the motor inrush followed by its sudden de-energization (due, in general, to the intervention of an automatic diagnostic function), resulting into important TRVs, are not unusual. The paper aims at investigating the TRVs due to this specific type of
VCB switching by means of a model implemented in the EMTP-RV simulation environment. By making reference to a real plant, the validation of the implemented models is obtained by comparing the simulation results with some experimental transients provided by the plant data fault recorder. The paper finally discusses the adequacy of different countermeasures by analyzing their effectiveness for the TRVs limitation.
Authors: A. Borghetti, F. Napolitano, C.A. Nucci, M. Paolone, M. Sultan, N. Tripaldi
CIGRE - International Symposium “Assessing and Improving Power System Security, Reliability and Performance in Light of Changing Energy Sources” Recife, Pernambuco, Brazil, April 3-6, 2011
Topic 3 – System technical performance
Subtopic 3.5 – Switching and lightning transient on power systems. Impact on performance and measurements
Tag(s): Transient recovery voltages, vacuum circuit breakers, motor inrush currents, EMTP simulations
Author: AdminEMTP-RV
Type:
Downloaded: 231 times
Date: 2012-06-18
Motor_Protection
Description:
The following circuit presents a protection scheme for an induction motor due to voltage dips.
The voltage dip generator is presented in a masked subcircuit where it is possible to control ... see morethe shape and duration of the voltage dip.
Tag(s): Motor, Protection
Author: AdminEMTP-RV
Type:
Downloaded: 220 times
Date: 2012-06-18
PM_subcircuit
Description:
Example of a user defined model. In this case a line-start permanent magnet synchronous machine is connected to a simple power network. This machine, working as a generator, has been modeled by contro... see morel elements. This user defined model is not recomme.
The line-start permanent magnet motor is a high-efficiency synchronous motor with self starting capability when operating from a fixed frequency voltage source. The permanent magnets embedded in its rotor provide the synchronous excitation and the rotor cage provides the induction motor torque for starting. The difference in permeability between the magnet and rotor core also results in significant magnetic saliency and reluctance torque at synchronous speed. At asynchronous speeds, the dc excitation and saliency of the permanent magnets will cause pulsating torque components. When the field strength of the magnet is too strong, a line-start permanent magnet motor may fail to synchronize because of the excessive pulsating torque component from the dc-excitation of the magnet.
The objective of this case is to create a user defined model of a permanent magnet synchronous machine. With this model the user can explore the behaviour of the torque components during a starting run of the generator from standstill. In particular, we will examine the ability of the motor to synchronize with various values of magnet field strength, mechanical loading and rotor inertia.
This case also shows the capabilities of EMTP-RV to create user defined models. This model assembled with control elements is particularly clear. I needed 4 hours to create this model and to validate it with an existing Simulink model ! The user can see the whole model with its equations on one page (see Figure below)
This model is given as an example of user defined model and should not be used for other purposes.
Author: AdminEMTP-RV
Type:
Downloaded: 184 times
Date: 2012-06-18
Self_Exc_ind
Description:
Simulation case of the self-excitation of induction motors during startup on a series compensated radial line.
This case reproduces the results published in the book of Anderson and Farmer ... see moreentitled 'Series Compensation of Power Systems', PBLSH publisher, 1996.
Although approximate data are used, results compare surprisingly well with the figures in chapter 7.
Tag(s): Motor