Influence of DC Bias and Remnant Flux on Measuring Current Transformers

2013 ◽  
Vol 765-767 ◽  
pp. 2268-2271
Author(s):  
Lu Shen ◽  
Shu Tao Zhao ◽  
Pei Zhang ◽  
Bin Hu ◽  
Xiao Qian Tian
Keyword(s):  
Power Systems ◽  
Electric Energy ◽  
Current Transformer ◽  
Simulation Software ◽  
Ratio Error ◽  
Phase Displacement ◽  
Limit Value ◽  
Exciting Current ◽  
Energy Metering ◽  
Dc Bias

Current transformer (CT) is an important transmission equipment in power systems. DC bias and remnant flux can change the working point of CT in the core magnetization curve and has a direct impact on the accuracy of electric energy metering and measurement. The simulation circuit model is built by using the simulation software PSCAD and the change of ratio error, phase displacement and exciting current with DC bias and remnant flux are analyzed. The results show that DC bias and remnant flux will both increase the ratio error and phase displacement in opposite directions and the error size will be far more than the limit value when DC bias and remnant flux exist in same direction at the same time. Furthermore, the existence of DC bias and remnant flux will also cause the raise of exciting current size, asymmetry of exciting current waveform and appearance of even harmonics. This will seriously affect the transmission accuracy of measuring CT.

Simulation and Analysis for Current Transformers with DC Bias and Remnant Flux

2013 ◽  
Vol 765-767 ◽  
pp. 2430-2434
Author(s):  
Xiao Qian Tian ◽  
Bao Shu Li ◽  
Lu Shen
Keyword(s):  
Error Compensation ◽  
Current Transformer ◽  
Scientific Basis ◽  
Current Transformers ◽  
Ratio Error ◽  
Full Wave ◽  
Accuracy Of Measurement ◽  
Dc Bias ◽  
Power Metering ◽  
Fourier Algorithm

The transfer characteristics of current transformers (CT) change due to DC bias, which directly impacts the accuracy of measurement and power metering. Based on equivalent circuit models and core magnetizing characteristic, qualitatively analysis current transformer saturation increase errors of CT. Transfer errors under DC bias and remnant flux are also obtained based on J-A model of CT in PSCAD/EMTDC and full-wave Fourier algorithm to show that the ratio error and phase displacement increase with the DC bias. Based on FFT spectrum analysis to identify remnant flux and DC bias provides scientific basis for error compensation of CT.

Error Analysis for Metering Current Transformer with DC Bias

2013 ◽  
Vol 773 ◽  
pp. 58-61
Author(s):  
Shi Hai Yang ◽  
Ke Qi Zhang ◽  
Zhong Zhuang ◽  
Min Rui Xu ◽  
Min Jian Cao ◽  
...  
Keyword(s):  
Error Analysis ◽  
Power System ◽  
Simulation Model ◽  
Digital Simulation ◽  
Current Transformer ◽  
Angle Error ◽  
Ratio Error ◽  
Dc Bias ◽  
Simulation Results ◽  
Different Levels

DC bias widely exists in power system. In order to analyze its influence on metering current transformer (MCT), a new digital simulation model based on Preisach theory is constructed firstly. Using this digital model, the ratio error and angle error of a running MCT are calculated under different levels of DC bias. Simulation results show that the current DC bias in power system has only little influence on the error of MCT.

scholarly journals AN AUTOMATED ENERGY BILL METERING SYSTEM BASED ON GSM TECHNOLOGY

2021 ◽  
Vol 19 (1) ◽  
pp. 25-39
Author(s):  
K. OKOKPUJIE ◽  
A. ABAYOMI-ALLI ◽  
O. ABAYOMI-ALLI ◽  
M. ODUSAMI ◽  
I. P. OKOKPUJIE ◽  
...  
Keyword(s):  
High Performance ◽  
Human Error ◽  
Electric Energy ◽  
Simulation Software ◽  
Power Monitoring ◽  
Full Control ◽  
C Programming ◽  
Energy Metering ◽  
Error Energy ◽  
Energy Theft

The measurement of the energy consumed by residential and commercial buildings by utility provider is important in billing, control, and monitoring of the usage of energy. Traditional metering techniques used for the measurement of energy are not convenient and is prone to different forms of irregularities. These irregularities include meter failure, meter tampering, inaccuracies in billing due to human error, energy theft, and loss of revenue due to corruption, etc. This research study proposed the design and construction of a microcontroller-based electric energy metering system using the Global System for Mobile communication (GSM) network. This system provides a solution to the irregularities posed by the traditional metering technique by allowing the utility provider have access to remote monitoring capabilities, full control over consumer load, and remote power disconnection in the case of energy theft. Proteus simulation software was used to model the system hardware and the software was obtained by using embedded C programming and visual basic. It was observed that the system could remotely take accurate energy readings, provided full control over consumer loads and execute remote disconnection in case of energy theft. The system provides high performance and high accuracy in power monitoring and power management.    

scholarly journals The Research on Anti-DC current Transformer of Dual Iron Core Structure with Air Gap

2021 ◽  
Vol 2133 (1) ◽  
pp. 012030
Author(s):  
Zhongai Lin ◽  
Xingyi Zhang ◽  
Biao Tang ◽  
Feng Shen
Keyword(s):  
Electrical Measurement ◽  
Current Transformer ◽  
Air Gap ◽  
System Stability ◽  
Iron Core ◽  
Saturation Current ◽  
Angle Error ◽  
Ratio Error ◽  
Dc Bias ◽  
Dc Current

Abstract Current transformer (CT) is wildly used in electrical measurement and relay protection. In order to improve the power system stability in DC bias, the CT performance of anti-DC is necessarily to be enhanced. Based on the Jiles-Atherton theory, the magnetization characteristics of iron core with different air gap was analyzed in this paper. A simulation model was established using the Simulink toolbox, and the ratio error and angle error were investigated in different air gap length. Simulation result shows that the maximum magnetic density of iron core almost stays uncharged with the addition of air gap. Furthermore the slope of magnetization curve decreased, which leads to the increase of iron core saturation current. Current transformer with closed and air gap iron core possesses a stable measurement error in condition of severe DC bias.

scholarly journals Technologies and Economics of Electric Energy Storages in Power Systems: Review and Perspective

2021 ◽  
pp. 100060
Author(s):  
Wei He ◽  
Marcus King ◽  
Xing Luo ◽  
Mark Dooner ◽  
Dacheng Li ◽  
...  
Keyword(s):  
Power Systems ◽  
Electric Energy

scholarly journals Analysis of Various Options for Balancing Power Systems’ Peak Load

Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 513
Author(s):  
Henryk Majchrzak ◽  
Michał Kozioł
Keyword(s):  
Power Systems ◽  
Distribution System ◽  
Peak Load ◽  
Electric Energy ◽  
End Users ◽  
Energy Market ◽  
Market Participants ◽  
Continuous Energy ◽  
Storage Solutions ◽  
Transmission And Distribution

The balancing of the power of the Polish Power System (KSE) is a key element in ensuring the safety of electric energy supplies to end users. This article presents an analysis of the power demand in power systems (PS), with emphasis on the typical power variability both in subsequent hours of the day and on particular days and in particular months each year. The methodology for calculating the costs of electric energy undelivered to the end users and the amount of these costs for KSE is presented. Different possibilities have been analyzed for balancing power systems’ peak load and assumptions have been formulated for calculating the amount of the related costs. On this basis, a comparative analysis has been made of the possibility to balance peak load using operators’ system services, trans-border connections, and various energy storage solutions. On the basis of the obtained results, optimal tools have been proposed for market-based influence from transmission and distribution system operators on energy market participants’ behaviors in order to ensure the power systems’ operating safety and continuous energy deliveries to end users.

scholarly journals Techno-economic feasibility analysis of a 3-kW PV system installation in Nepal

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Ramhari Poudyal ◽  
Pavel Loskot ◽  
Ranjan Parajuli
Keyword(s):  
Net Present Value ◽  
Meteorological Data ◽  
Electric Energy ◽  
Simulation Software ◽  
Economic Feasibility ◽  
Performance Ratio ◽  
Energy Output ◽  
Solar Pv ◽  
Economic Returns ◽  
Pv System

AbstractThis study investigates the techno-economic feasibility of installing a 3-kilowatt-peak (kWp) photovoltaic (PV) system in Kathmandu, Nepal. The study also analyses the importance of scaling up the share of solar energy to contribute to the country's overall energy generation mix. The technical viability of the designed PV system is assessed using PVsyst and Meteonorm simulation software. The performance indicators adopted in our study are the electric energy output, performance ratio, and the economic returns including the levelised cost and the net present value of energy production. The key parameters used in simulations are site-specific meteorological data, solar irradiance, PV capacity factor, and the price of electricity. The achieved PV system efficiency and the performance ratio are 17% and 84%, respectively. The demand–supply gap has been estimated assuming the load profile of a typical household in Kathmandu under the enhanced use of electric appliances. Our results show that the 3-kWp PV system can generate 100% of electricity consumed by a typical residential household in Kathmandu. The calculated levelised cost of energy for the PV system considered is 0.06 $/kWh, and the corresponding rate of investment is 87%. The payback period is estimated to be 8.6 years. The installation of the designed solar PV system could save 10.33 tons of CO2 emission over its lifetime. Overall, the PV systems with 3 kWp capacity appear to be a viable solution to secure a sufficient amount of electricity for most households in Kathmandu city.

scholarly journals Optimised calibration programmes for comparators for instrument transformers

2021 ◽  
Vol 88 (2) ◽  
pp. 122-131
Author(s):  
Christian Mester
Keyword(s):  
Experimental Study ◽  
Operating Principle ◽  
Device Under Test ◽  
Operating Range ◽  
Ratio Error ◽  
Phase Displacement ◽  
Instrument Transformers ◽  
Instrument Transformer ◽  
Method Of Measurement

Abstract Traditionally, instrument transformers are calibrated using bridges. By definition, bridges use the null method of measurement. The traditional calibration programme for instrument transformer bridges characterise namely this null measurement. Many new commercial comparators for instrument transformer use a very different method. They sample the secondary signals of reference and device under test (dut) transformer independently. Based on the samples, magnitude and phase of both signals are determined. Ratio error and phase displacement are calculated. Consequently, the significance of their calibration using the traditional calibration programme is limited. Moreover, the operating range of modern comparators is much larger than that of bridges. The additional versatility cannot be used without an adapted calibration programme. This article analyses the calibration programmes for both technologies. An experimental study confirms both the suitability of the new calibration programme and the need to chose the calibration programme depending on the technology of the device to be calibrated. The conclusion is very general and applies to all measurement problems where an operating principle is replaced by another – when changing the operating principle, it is important to check the calibration programme and adapt it if necessary.

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