Simulation Model for Assessing Operational Performance of Current Transformers

2007 ◽  
Vol 18-19 ◽  
pp. 71-77
Author(s):  
I. Sule
Keyword(s):  
Simulation Model ◽  
Current Transformer ◽  
Operational Performance ◽  
Current Transformers ◽  
Correct Operation ◽  
Operational Conditions ◽  
Secondary Current ◽  
Protection Scheme ◽  
The Core ◽  
Instrument Transformers

In determining the correct operation of relays of a protection scheme, proper representation of instrument transformers and their behavior in conditions where there can be saturation, is very critical. The main objective of this paper is to develop simulation model for assessing the operational performance of Current Transformer (CT). In order to test the validity of the developed model, three cases of CT operational conditions were considered, with data collected from Gombe, 330/132/33kV PHCN substation. The simulation results revealed various configuration performance responses that could affect relay protective schemes to different degrees. The CT responses revealed that the secondary current and voltage were distorted when the core flux linkages exceeded the set 9.2 pu saturation limit. It is concluded that the model developed for the CT of interest yield satisfactory results.

scholarly journals Reach and Operating Time Correction of Digital Distance Relay

2017 ◽  
Vol 7 (1) ◽  
pp. 58
Author(s):  
A N Sarwade ◽  
P K Katti ◽  
J G Ghodekar
Keyword(s):  
Low Voltage ◽  
Electrical Power ◽  
Operating Time ◽  
Current Transformer ◽  
Iron Core ◽  
Electrical Power System ◽  
Voltage Transformer ◽  
Distance Relay ◽  
Correct Operation ◽  
Secondary Current

Current and voltage signals recieved from conventional iron core Current Transformer (CT) and Voltage Transformer plays very important role for correct operation of Distance Distance Relay (DDR). Increase in secondary burden connected to CT causes it to saturate at earlier stage. The saturated CT produces distorted secondary current, causing DDR to under reach and to operate by certain time delay. Rogowski Coils (RCs) are attaining increased acceptance and use in electrical power system due to their inherent linearity, greater accuracy and wide operating current range. This paper presents use of RC as an advanced measurement device suitable for DDR. Case study for validation of use of RC is carried out on low voltage system. The simulation results of Distance protection scheme used for protection of part of 220kV AC system shows excellent performance of RC over CT under abnormal conditions.

Analiza algoritama za kompenzaciju zasićenja strujnog transformatora

2020 ◽  
Vol 22 (1-2) ◽  
pp. 112-118
Author(s):  
Nenad Belčević ◽  
◽  
Zoran Stojanović
Keyword(s):  
Relay Protection ◽  
Current Transformer ◽  
Main Function ◽  
Negative Consequences ◽  
Current Transformers ◽  
Secondary Current ◽  
Measuring Devices ◽  
Protection Devices ◽  
Primary Current ◽  
A Current

The main function of current transformers is to adapt the high values of the primary current to values suitable for the operation of relay protection devices, i.e. measuring devices. Under normal conditions, a current transformer transforms the current in a virtually permanent ratio, and practically without a phase shift, so the secondary current is actually a scaled value of the primary current. However, when a fault occurs in the power system, currents reach high values. As a result, the flux in the core of the current transformer can reach values above the knee of the magnetization characteristic, causing saturation of the current transformer. When saturation occurs, the secondary current is no longer a scaled value of the primary current, but is deformed. Deformation of the secondary current may cause malfunctioning of some relay protection devices. The development of digital relay protection has made it possible to perform software saturation compensation by applying certain algorithms, thus eliminating the negative consequences that saturation of the current transformer causes. In this paper, one of the possible approaches for compensation of saturation is analyzed, which is based on the application of an equivalent scheme and magnetization curve of the current transformer. Two typical approaches have been singled out, which have been analyzed and tested in more detail. Testing was performed in the MATLAB/Simulink.

scholarly journals Impact of optical current transformer on protection scheme of hybrid transmission line

2021 ◽  
Vol 24 (1) ◽  
pp. 1
Author(s):  
Zainal Arifin ◽  
Muhammad Zulham ◽  
Eko Prasetyo
Keyword(s):  
Transmission Line ◽  
Fault Location ◽  
Power Transmission ◽  
Current Transformer ◽  
System Stability ◽  
Protection Scheme ◽  
Circulating Current ◽  
Instrument Transformers ◽  
Hybrid Transmission ◽  
The Impact

Continuity of power transmission is important to ensure the reliability of the electricity supply. As most system faults are temporary, the auto reclose (AR) scheme has been used extensively to minimise the outage duration, prevent widespread outages, thus increase system stability. Meanwhile, the hybrid transmission line (HTL) combining overhead line (OHL) and high voltage cable has been introduced to provide an inexpensive solution for an urban power grid. Protecting HTL with a conventional protection system would forbid the operation of the AR scheme due to difficulty to ensure whether the fault occurred on the OHL or cable section. Therefore, the circulating current protection (CCP) scheme is used in the cable section to ensure the fault location and block the AR scheme. The technology of an optical current transformer (OCT) as one of the non-conventional instrument transformers (NCIT) has emerged to provide a solution to drawbacks on the conventional current transformer (CCT). Consequently, this paper investigated the impact of using OCT over the CCT for CCP of the HTL. The result shows that OCT could be used for CCP on much longer cable sections thus increase its reliability as the AR scheme can be used on longer or multiple cable section.

Sensitivity Analysis and Selection of Check Index of Signal Intersection Simulation Model Based on VISSIM

2019 ◽  
Vol 2 (5) ◽  
Author(s):  
Mengda Zhang ◽  
Chenjing Zhou ◽  
Tian-tian Zhang ◽  
Yan Han
Keyword(s):  
Sensitivity Analysis ◽  
Simulation Model ◽  
Optimal Process ◽  
Parameter Calibration ◽  
Index Set ◽  
The Core ◽  
Core Module ◽  
Simulation Parameter ◽  
Simulation Parameters ◽  
Selection Of

Selecting check index quantitatively is the core of the calibration of micro traffic simulation parameters at signal intersection. Five indexes in the node (intersection) module of VISSIM were selected as the check index set. Twelve simulation parameters in the core module were selected as the simulation parameters set. Optimal process of parameter calibration was proposed and model of the intersection of Huangcun west street and Xinghua street in Beijing was built in VISSIM to verify it. The sensitivity analysis between each check index and simulation parameter in their own set was conducted respectively. Sensitive parameter sets of different check indices were obtained and compared. The results show that different indexes have different size of set, and average vehicle delay's is maximum, so it's necessary to select index quantitatively. The results can provide references for scientific selection of the check indexes and improve the study efficiency of parameter calibration.

scholarly journals Use of simulation model for measurement of MilkRun system performance

2019 ◽  
Vol 9 (1) ◽  
pp. 600-605 ◽  
Author(s):  
Gabriel Fedorko ◽  
Martin Vasil ◽  
Michaela Bartosova
Keyword(s):  
Simulation Model ◽  
Production Systems ◽  
Operational Performance ◽  
Transport Systems ◽  
Indirect Methods ◽  
Operational Characteristics ◽  
Wide Range ◽  
Effective Operation ◽  
And Performance ◽  
Plant Simulation

AbstractIntra-plant transport systems within their operation directly impact on the performance of production systems. For their effective operation, it is, therefore, necessary to realize evaluation of operational performance and effectivity. For the realization of this type of evaluation, in addition to a wide range of sensors that can be difficult for installation and operation, we can also use indirect methods that are equally able to provide reliable operational characteristics. Indirect analytical methods are presented above all by the approach which is based on the use of simulation methods. The method of computer simulation provides a wide range of options for the evaluation of efficiency and performance. The paper describes the use of a simulation model created in the program Tecnomatix Plant Simulation for analyzing the supply of production workplaces within the MilkRun system.

Effect of dynamically varying zone-based hedging policies on the operational performance of surface water reservoirs during climate change

2018 ◽  
Vol 488 (1) ◽  
pp. 277-289 ◽  
Author(s):  
Adebayo J. Adeloye ◽  
Bankaru-Swamy Soundharajan
Keyword(s):  
Climate Change ◽  
Surface Water ◽  
Operational Performance ◽  
Dynamic Hedging ◽  
Water Reservoirs ◽  
Complex Dynamic ◽  
Water Shortages ◽  
Operational Conditions ◽  
Static Hedging ◽  
The Impact

AbstractHedging is universally recognized as a useful operational practice in surface water reservoirs to temporally redistribute water supplies and thereby avoid large, crippling water shortages. When based on the zones of available water in storage, hedging has traditionally involved a static rationing (i.e. supply to demand) ratio. However, given the usual seasonality of reservoir inflows, it is also possible that hedging could be dynamic with seasonally varying rationing ratios. This study examined the effect of static and dynamic hedging policies on the performance of the Pong reservoir in India during a period of climate change. The results show that the reservoir vulnerability was unacceptably high (≥60%) without hedging and that this vulnerability further deteriorated as the catchment became drier due to projected climate change. The time- and volume-based reliabilities were acceptable. The introduction of static hedging drastically reduced the vulnerability to <25%, although the hedging reduction in the water supplied during normal operational conditions was only 17%. Further analyses with dynamic hedging provided only modest improvements in vulnerability. The significance of this study is its demonstration of the effectiveness of hedging in offsetting the impact of water shortages caused by climate change and the fact that static hedging can match more complex dynamic hedging policies.

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