Suppression of very fast transients in 245 kV gas insulated substation

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Subramania Prasad Visakan ◽  
Mandava Mohana Rao ◽  
Mritunjay Kumar ◽  
Karakkad Sunitha
Keyword(s):  
Equivalent Circuit Model ◽  
Dominant Frequency ◽  
Electromagnetic Transients ◽  
Nano Crystalline ◽  
Frequency Components ◽  
Fast Transients ◽  
Fast Transient ◽  
Gas Insulated Substation ◽  
Transient Voltages ◽  
Program Software

Abstract Very Fast Transient Over voltages (VFTOs) generate during operation of the disconnector switches or circuit breakers in a gas insulated substation (GIS). These transient voltages stress the insulation system in GIS and further result in mal-operation of the control circuitry as well as the secondary equipment connected to it. Since the VFTOs affect the reliability of GIS, it is necessary to mitigate them. This paper presents the mitigation of the very fast transient over voltages and the associated very fast transient currents (VFTCs) using the nano-crystalline rings in a 245 kV GIS. The mitigation in the peak amplitude of VFTOs and VFTCs at various locations in the GIS for various switching configurations are analyzed in this paper. The nano-crystalline rings of different geometries and permeabilities are considered to understand the damping effect being offered. The nano-crystalline rings are considered at all the possible switches of 245 kV GIS bays. An equivalent circuit model of the nano-crystalline ring is obtained through an iterative algorithm. The very fast transients have been calculated using Electromagnetic Transients Program software. Further, attenuation in the dominant frequency components of VFTOs and VFTCs at different GIS components is also studied for various switching configurations with nano-crystalline rings.

Experimental Study of Fast Transient Currents in Gas Insulated Substation

2019 ◽  
Vol 20 (6) ◽  
Author(s):  
Visakan S ◽  
Mandava Mohana Rao ◽  
Mritunjay Kumar ◽  
Sunitha K
Keyword(s):  
Electrical Energy ◽  
Dominant Frequency ◽  
Service Reliability ◽  
Transient Currents ◽  
Switching Operation ◽  
Fast Transient ◽  
Gas Insulated Substation ◽  
Increasing Demand ◽  
Comparison Of The Results ◽  
Transient Voltages

Abstract The increasing demand in transmitting electrical energy at very high voltages with low transmission losses and improved efficiency has led to the development of compact metal enclosed gas insulated substation. There are various advantages of gas insulated substations over conventional substations yet there are a few problems associated with the switching operation in gas insulated substation. The fast transient voltages arising due to the switching operation of disconnectors or circuit breakers may impair the service reliability. The fast transient currents are associated with these fast transient voltages. The main aim of this paper is to characterize the fast transient currents generated due to the switching operations in a gas insulated substation. The dominant frequency content has been identified for different rise times of the fast transient currents and the percentage attenuation in amplitude is determined at different distances from the source. The variation in the peak value of current with distance from the source is also analysed. The experimental work is carried out on 145 kV gas insulated substation models of different configurations and comparison of the results for different case studies are reported.

scholarly journals Analysis of Very Fast Transients Using Black Box Macromodels in ATP-EMTP

Energies ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 698
Author(s):  
Jonathan James ◽  
Maurizio Albano ◽  
David Clark ◽  
Dongsheng Guo ◽  
Abderrahmane (Manu) Haddad
Keyword(s):  
Finite Element ◽  
Electromagnetic Transients ◽  
Element Analysis ◽  
Simple Method ◽  
Model Order ◽  
High Frequencies ◽  
Transient Simulations ◽  
Improved Stability ◽  
Fast Transients ◽  
Gas Insulated Substation

Modelling for very fast transients (VFTs) requires good knowledge of the behaviour of gas insulated substation (GIS) components when subjected to high frequencies. Modelling usually takes the form of circuit-based insulation coordination type studies, in an effort to determine the maximum overvoltages and waveshapes present around the system. At very high frequencies, standard transmission line modelling assumptions may not be valid. Therefore, the approach to modelling of these transients must be re-evaluated. In this work, the high frequency finite element analysis (FEA) was used to enhance circuit-based models, allowing direct computation of parameters from geometric and material characteristics. Equivalent models that replicate a finite element model’s frequency response for bus-spacer and 90° elbow components were incorporated in alternative transients program-electromagnetic transients program (ATP-EMTP) using a pole-residue equivalent circuit derived following rational fitting using the well-established and robust method of vector fitting (VF). A large model order is often required to represent this frequency dependent behaviour through admittance matrices, leading to increased computational burden. Moreover, while highly accurate models can be derived, the data extracted from finite element solutions can be non-passive, leading to instability when included in time domain simulations. A simple method of improved stability for FEA derived responses along with a method for identification of a minimum required model order for stability of transient simulations is proposed.

scholarly journals HHT based analysis on seismic response recordings for a base-isolated building

2019 ◽  
Vol 277 ◽  
pp. 02021
Author(s):  
Fei Wang ◽  
Xiandong Kang ◽  
Ting Yan ◽  
Ying Liu
Keyword(s):  
Seismic Response ◽  
Dominant Frequency ◽  
Data Series ◽  
Structural Systems ◽  
Original Signal ◽  
Intrinsic Mode Functions ◽  
Hilbert Huang Transform ◽  
Mode Decomposition ◽  
Frequency Components ◽  
Emd Method

Hilbert-Huang transform (HHT) is proposed to process the seismic response recordings in an 8-story frame-shear wall base-isolated building. Empirical Mode Decomposition (EMD) method is first applied to identify the time variant characteristics and the data series can be decomposed into several components. Hilbert transform is well-behaved in identifying the frequency components. The first 5 intrinsic mode functions (IMFs) are decomposed with their different frequencies. The analytical function is reconstructed and compared with the original signal. They are extremely consistent in amplitude and phase. Based on the IMFs obtained, frequencies of the original signal are inferred at 5 Hz and 1.6 Hz. The higher frequency is regarded as the vibration excited by surface waves. 1.6 Hz is suggested as the dominant frequency of the building. Analysis indicates that HHT is accurate in extracting the dynamic characteristics of structural systems.

TITRAM Fast Transient Licensing Analysis Methodology for Kuosheng BWR/6

2010 ◽  
Author(s):  
Jan-Ru Tang ◽  
Hon-Chin Jien ◽  
Yang-Kai Chiu ◽  
Cheng-Der Wang ◽  
Julian S. C. Chian
Keyword(s):  
Nuclear Power ◽  
Transient Analysis ◽  
Nuclear Regulatory Commission ◽  
Nuclear Industry ◽  
Evaluation Methodology ◽  
Uncertainty Evaluation ◽  
Power Company ◽  
Fast Transients ◽  
Fast Transient ◽  
Regulatory Commission

This paper presents the TITRAM (TPC/INER Transient Analysis Method) methodology for the fast transient analysis of Kuosheng Nuclear Power Station (KSNPS) with two units of General Electric (GE) designed BWR/6 (Boiling Water Reactor). The purpose of this work is to provide a technical basis of Taiwan Power Company (TPC)/Institute of Nuclear Energy Research (INER)’s qualification to perform plant specific licensing safety analyses for the Final Safety Analysis Report (FSAR) basis system fast transients, and related plant operational transient analyses for the Kuosheng plant. The major task of qualifying TITRAM as a licensing method for BWR transient analysis is to adequately quantify its analysis uncertainty. A similar approach as the CSAU (Code Scaling, Applicability, and Uncertainty Evaluation) methodology developed by the USNRC (United States Nuclear Regulatory Commission) was adopted. The CSAU methodology could be characterized as three significant processes, namely code applicability, transient scenario specification and uncertainty evaluation based on Phenomena Identification and Ranking. The applicability of the TITRAM code package primarily using the SIMULATE-3 and RETRAN-3D codes are demonstrated with analyses of integral plant tests such as Peach Bottom Turbine Trip Test and plant startup tests of KSNPS. A Phenomena Identification and Ranking Table (PIRT) with uncertainty values for each identified parameter to cover 95% of possible values are established for the selected KSNPS fast transients. The experience from BWR organizations in the nuclear industry is used as a guide in construction of the PIRT. Sensitivity studies and associated statistical analyses are performed to determine the overall uncertainty of fast transient analysis with TITRAM based on the KSNPS Analysis Nominal Model. Finally, the Licensing Model is established for future licensing applications.

scholarly journals Development of an on-site system for measuring the low-frequency noise and complainant’s responses

2018 ◽  
Vol 37 (2) ◽  
pp. 373-384
Author(s):  
Hiroshi Sato ◽  
Jongkwan Ryu ◽  
Kenji Kurakata
Keyword(s):  
Time Trends ◽  
Sound Pressure ◽  
Low Frequency ◽  
Dominant Frequency ◽  
Pressure Level ◽  
Frequency Noise ◽  
Low Frequency Noise ◽  
Measurement Results ◽  
Frequency Components ◽  
The Relationship

An on-site system for measuring low-frequency noise and complainant's responses to the low-frequency noise was developed to confirm whether the complainant suffer from the environmental noise with low-frequency components. The system suggests several methods to find the dominant frequency and major sound pressure level spectrum of the noise causing annoyance. This method can also yield a quantified relationship (correlation coefficient and percentage of response to the noise) between physical noise properties and the complainant’s responses. The advantage of this system is that it can easily find the relationship between the complainant’s response to the acoustic event of the houses and the physical characteristics of the low-frequency noise, such as the time trends and frequency characteristics. This paper describes the developed system and provides an example of the measurement results.

Sign in / Sign up

Export Citation Format

Share Document