Harmonic content as the indicator of transformer core saturation

Ismail, Daut; Hasan, Sharizal; Taib, Soib; Chan, Risnidar; Irwanto, M.

doi:10.1109/peoco.2010.5559192

Cited by 7 publications

(3 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As the amplitude of the 50 Hz current increases, the measured output voltage becomes more and more non-sinusoidal due to increasing core saturation, i. e., its harmonic distortion increases (nonlinear operation). Calculating the total harmonic distortion (THD) of the 50 Hz component of the measured HFCT output voltage u L (t) therefore provides a good measure for determining the saturation level of the core [9]. If the output voltage is sinusoidal, the THD approaches 0, which means that the HFCT core is free of magnetic saturation [3].…”

Section: B Servomotor Controlmentioning

confidence: 99%

High-Frequency Current Transformer With Variable Air Gap for Power Cable Monitoring

Fritsch,

Wolter

2024

IEEE Trans. Instrum. Meas.

View full text Add to dashboard Cite

This article deals with partial discharge (PD) measurement on power cables while they are in operation (online monitoring). In terms of sensitivity, high-frequency current transformers (HFCTs) are the most suitable sensors for this task, but they are prone to magnetic saturation when monitoring power cables online. To counteract saturation, the magnetic ring core of the HFCT is usually split into two halves to create air gaps. We show that a variable air gap length is required to maximize the HFCT sensitivity, and that the optimal air gap length depends on the actual operating point of the power cable. Accordingly, we present a concept for the construction of an HFCT capable of self-adjusting its air gap length during operation. The air gap control strategy is explained in detail and tested with a prototype. In addition, we propose a method for PD detection based on a combination of an analog peak detector circuit followed by a software algorithm. The developed PD sensor is immune to magnetic saturation, always operates at its optimum operating point and can therefore detect PD pulses with much higher sensitivity than comparable sensors with a fixed air gap length. Our tests prove that the sensor system works as intended and will be further improved in the future.

show abstract

Section: B Servomotor Controlmentioning

confidence: 99%

High-Frequency Current Transformer With Variable Air Gap for Power Cable Monitoring

Fritsch,

Wolter

2024

IEEE Trans. Instrum. Meas.

View full text Add to dashboard Cite

show abstract

“…The impact of an iron core under fault conditions in IVTs and ICTs can be mitigated by altering the structure, core material, wire thickness, and number of turns to alleviate saturation for accurate measurements. However, there are limitations such as increases in the size, weight, and cost of ITs [49][50][51].…”

Section: Conventional Instrument Transformersmentioning

confidence: 99%

Trends in Measuring Instrument Transformers for Gas-Insulated Switchgears: A Review

Kim,

Lee,

Kil

et al. 2024

Energies

View full text Add to dashboard Cite

Voltage and current measurements in high-voltage substations are fundamental for stable operation. Conventional instrument transformers (ITs) face challenges in gas-insulated switchgears (GISs), such as size, weight, accuracy limitations, and behavioral instability at abnormal voltages and currents. Non-conventional instrument transformers (NCITs) have emerged to address these issues, complying with International Electrotechnical Commission (IEC) standards and providing millivolt-level signals, enabling downsizing of GIS bays. The transition to digital substations, as mandated by IEC 61850-9-2, requires a shift from the conventional 110 V/5 A outputs to levels ranging from millivolts to volts. Electronic instrument transformers (EITs), compliant with the IEC 60044-7 and 8 standards, offer alternatives to conventional ITs with smaller sizes and wider frequency ranges. However, issues remain with EITs, including limited adoption, the necessity of separate power sources, and susceptibility to electromagnetic interference. Recent standards, transitioning to IEC 61869, focus on low-power instrument transformers (LPITs). Low-power voltage transformers (LPVTs) and low-power current transformers (LPCTs), designed with passive components, present potential solutions by directly connecting to merging units (MUs) for digital signal transmission. This review outlines the current status of various IT standards, covering conventional ITs, EITs based on IEC 60044-7 and 8, and LPITs based on IEC 61869-10 and 11. Advancements in sensor technology relevant to these standards are also explored. The paper provides insights into the evolving landscape of instrument transformers, addressing challenges and offering potential pathways for future developments in digital substations.

show abstract

“…Increase of flux density is possible [14]. A saturated magnetic core acts as current distortion source which affects the winding losses [15]. It also acts as generator of harmonic current where they circulate inside a transformer depending on its reactances of the input and output [16].…”

Section: Effects Of Current Harmonics Towards Power Transformer Opera...mentioning

confidence: 99%

Comparison of Operational Losses under Rated and Nonlinear Loads for 2 kVA Three-Phase Three Legged Dry Type Power Transformer

Azizan

Ismail

Masri

et al. 2015

AMM

View full text Add to dashboard Cite

This paper produces experimental results comparing operational loss of a power transformer under rated and nonlinear load. A 2kVA three phase three legged dry type power transformer is primarily designed for rated loss; however it is operated with a nonlinear load. Three phase rectifier with variable capacitors is the selected current harmonic source and the distortion at current waveform is controlled by the capacitance values. Initially the operation losses under rated load is measured and then followed with measurement with nonlinear load. At the end of this paper, both type of operation losses is compared and differentiated.

show abstract

Harmonic content as the indicator of transformer core saturation

Cited by 7 publications

References 4 publications

High-Frequency Current Transformer With Variable Air Gap for Power Cable Monitoring

High-Frequency Current Transformer With Variable Air Gap for Power Cable Monitoring

Trends in Measuring Instrument Transformers for Gas-Insulated Switchgears: A Review

Comparison of Operational Losses under Rated and Nonlinear Loads for 2 kVA Three-Phase Three Legged Dry Type Power Transformer

Contact Info

Product

Resources

About