Access to EMTP user presentations, webinars, and slide deck presentations.
22 presentations for Cable:
Author(s): Theofilos Papadopoulos
Type:Technical Presentation
Date: 2021-09-03
Abstract
Scope of the presentation is to present results regarding inductive electromagnetic interference (EMI) between a real HVDC link and the nearby communication cables of a railway system under pole-to-gr... see moreound fault conditions.
?he HVDC and the railway system route in parallel at a part of the onshore section of the HVDC link. The inductive EMI on the communication cable arises from magnetic field variation of the high-frequency components contained in the transient response of the fault current, excited by the HVDC link.
Consequently, it is expected that no inductive EMI will occur by the DC current in the case of the HVDC system normal operation (steady-state) either in bipolar or monopolar (current return though the electrode) mode. The induced transient voltages and currents are calculated using the Electromagnetic Transients Program (EMTP).
Tag(s): emi, wb cable, hvdc, interference
Author(s): Andreia Leiria
Type:Technical Presentation
Date: 2021-09-02
Abstract
Overvoltages were identified on the MV and LV networks of a Hydro Power Plant as the cause of the trip of the LV maximum voltage protection, compromising the normal operation of the system. Following ... see morethis event, measurements were conducted and the presence of a very high 23rd harmonic, potentially responsible for the various overvoltages, was identified associated to the operation of the Plant’s Synchronous Machine Frequency Control System (FCS). It was concluded then that this harmonic would have its origin in the FCS and would be amplified due to a possible resonance in the Power Plant internal network. A digital simulation study, using EMTP, was conducted to identify and characterize the resonance in the system and to propose mitigation solutions. The simulation models were developed using the equipment data and the system characteristics. The models were duly validated with measurements made both in time and frequency domains and it was possible to identify the origin of the overvoltages and their propagation in the system. It was concluded that the resonance occurred between a 30/11 kV Power Transformer and a 30 kV cable with 850 m.
This conclusion was supported by the results obtained in the measurements. Several alternatives were analyzed as mitigation solutions: - Installation of capacitors; - Different bonding techniques of the 30 kV cable sheaths; - Changing the 30 kV cable length; - Installation of a harmonic filter; The advantages and disadvantages of each solution were weighed also considering the ease of implementation, namely the available room. It was concluded that the installation of capacitors would be the best option. Measurements were conducted after the capacitor’s installation confirming the success of this solution.
Tag(s): harmonics, power uality, resonance
Author(s): N.K. Nathan
Type:Technical Presentation
Date: 2021-09-01
Abstract
Transient enclosure voltage (TEV) also known as Transient ground potential rise (TGPR) is a special case of VFTO. This phenomenon refers to short rise time, short duration high voltage transient which... see more appear on earthed enclosure of GIS. This is mainly through the coupling of internal transients on conductor refracted to the enclosure at enclosure discontinuities such as air terminations, insulated flanges at GIS/Cable interfaces and some current transformers. Primarily disconnector switch operations are causes of VFTO and SF6-Air bushing seems to be the most significant source of TEV.
Observation of sparking between grounded enclosure and support structure, failure of protective devices, inadvertent operation of relays etc are common malfunction of TEV. Despite proper grounding this phenomenon indicates presence of high potentials on GIS enclosures which raises the issue of equipment protection, migration of these transients to adjacent equipment and shock hazards.
TEV in 400kV GIS substation due to “disconnector switch operation” was studied and simulations performed for GIS model with the equivalent resistance of ground grid, resistance and inductance of grounding strip using EMTP. The presentation summarizes the results of study needed for a 400kV GIS substation in India to ascertain VFTO induced TGPR level. The study was carried out by modeling all GIS equipment, enclosure in EMTP and careful consideration of grounding system model. The results of the study were analyzed to decide on the requirement of mitigation methods to ensure the permissible level of TEV.
Tag(s): gis, vfto, very fast transient
Author(s): N.K. Nathan
Type:Technical Presentation
Date: 2021-09-01
Abstract
Transient enclosure voltage (TEV) also known as Transient ground potential rise (TGPR) is a special case of VFTO. This phenomenon refers to short rise time, short duration high voltage transient which... see more appear on earthed enclosure of GIS. This is mainly through the coupling of internal transients on conductor refracted to the enclosure at enclosure discontinuities such as air terminations, insulated flanges at GIS/Cable interfaces and some current transformers. Primarily disconnector switch operations are causes of VFTO and SF6-Air bushing seems to be the most significant source of TEV.
Observation of sparking between grounded enclosure and support structure, failure of protective devices, inadvertent operation of relays etc are common malfunction of TEV. Despite proper grounding this phenomenon indicates presence of high potentials on GIS enclosures which raises the issue of equipment protection, migration of these transients to adjacent equipment and shock hazards.
TEV in 400kV GIS substation due to “disconnector switch operation” was studied and simulations performed for GIS model with the equivalent resistance of ground grid, resistance and inductance of grounding strip using EMTP. The presentation summarizes the results of study needed for a 400kV GIS substation in India to ascertain VFTO induced TGPR level. The study was carried out by modeling all GIS equipment, enclosure in EMTP and careful consideration of grounding system model. The results of the study were analyzed to decide on the requirement of mitigation methods to ensure the permissible level of TEV.
Tag(s): gis, vfto, very fast transient
Author(s): Jesus Morales
Type:Technical Presentation
Downloaded: 15
Date: 2021-08-31
Abstract
1. Brief review of transmission line equations
2. Per unit length parameter
- Traditional line data and cable data
- MoM-SO and Extended TL theory
3. New Line/Cable dat... see morea
- Mask options
- Application examples
Tag(s): EMT simulations, transmission, cable data,
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