Technical Presentations

Ground Fault Detection and Feeder Protection of 2x25kV Railway Traction System840

Abstract
In a new 2X25 kV System, Scott transformer is used as a traction transformer and to supply the power to the railway traction system. It is protected using the percentage differential relay.

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However, region from the low voltage side of the Scott transformer to the first autotransformer is unprotected at the field and to protect the system during fault on this region is very important. Thus, development of protection scheme is required. Herein, we modeled 2X25kV traction system in EMTP, simulate faults and developed a specific relationship to provide the protection for this scheme. We have taken the current input from feeder current transformers and observed its current during the faults.


This performance of this scheme is verified using EMTP. Further, impedance to distance ratio is non-linear due to the autotransformer between catenary, rail and feeders in 2x25kV railway traction system. To observe this behavior as per field details and provide the accurate relay setting, we simulate the faults over the length of protected line in EMTP and field test are carried out. In the event of a fault on unprotected region and on the protected line, trip occurs and relay recorded fault details at the field.

Tag(s): Fault Detection, protection, railway, traction

Simulation of Inductive EM Interference Caused by an HVDC Underground Cable Link on a Railway System853

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

Design and Performance Assessment of Harmonic Filters Using EMTP835

Abstract
In order to permit access to a public electricity network, a network operator will impose compliance with certain technical requirements, which must be met by the potential network user seeking the co... see morennection to the network.
These technical requirements are typically quite extensive and detailed and generally include requirements for compliance with power quality standards, including harmonic distortion standards. As a result of the requirement to comply with harmonic distortion standards and the requirements therein, it is sometimes necessary to provide harmonic filtering in order to ensure the public network will remain within the required harmonic distortion limits under all normal operating conditions.
This presentation gives a study case for a connection to a 400kV network which required design and installation of a number of filters in order to ensure compliance with the harmonic distortion limits on the public network.
As part of the assessment and design process, a number of studies was undertaken in order to ensure all aspects of the filter system design perform as required, under all operating conditions. These studies included:
• harmonic propagation and distortion calculations,
• filter configuration and optimisation studies,
• filter loading studies,
• filter transient studies,
• filter protection studies.


The tool used in the assessments was EMTP. The presentation will demonstrate certain aspects of the EMTP capability and use in steady state and electromagnetic transient studies applied to the filter system design, validation and compliance studies.

Tag(s): railway, traction, power quality, harmonics, scripting

Performance Analysis of DC Primary Power Protection in Railway Cars using EMTP-R586

Abstract

Modelling of 25 kV Electric Railway System in EMTP690

Abstract