X. Liu

Partial discharge measurements in air and argon at low pressures with and without a dielectric barrier

Partial discharge (PD) characteristics in air and argon under low pressures down to 13.3 Pa (0,1 Torr) and 60 Hz AC energization are studied in an energized needle-plane electrode arrangement. The electrode configuration, vacuum chamber, facilities, and electrical connections for the experimental setup are described. Two cases are studied for each of two gases, air and argon, with 20 mm spacing between the two electrodes: (1) with and (2) without a Teflon/spl reg/ cap (dielectric barrier). Results for the four series of experiments and analysis of the discharge current pulse waveforms are presented. Topics discussed are the typical waveforms of the discharge current pulses at different pressures, and discharge current pulse rise time vs. pressure relationships.

Development of procedures for partial discharge measurements at low pressures in air, argon and helium

Partial discharge (PD) characteristics in air, argon and helium at pressures between 101 kPa (760 Torr) to about 0.27 kPa (2 Torr) under 60 Hz AC energization were studied with various electrode arrangements. Measurements are presented for two representative electrode configurations, (1) needle-plane, with 20 mm spacing and a dielectric barrier, and (2) a twisted pair of insulated conductors. Typical PD current pulse waveforms are presented. Difficulties in adhering to measurement guidelines defined by the IEC 60270 standard are described, and suggested modifications of the standard procedures are presented for measurement and calibration for low-pressure PD.

Partial discharge measurements-frequency related considerations

Partial discharge (PD) test circuits have been developed for various test series in different gases in the 13.3 Pa to 101.3 kPa pressure range with a needle-plane electrode arrangement. (The purpose of the test series is to establish results in terms of PD inception voltage, waveforms and rise times.) The paper describes features of the initial and improved test circuits, in terms of components, circuit layout, grounding and safety aspects. Impedance vs. frequency measurements performed in the 1 kHz-200 MHz frequency range are reviewed and discussed. PD current waveform measurement procedures are also reviewed. Waveform measurements are analyzed in terms of the initial rise time and the discharge rate of the coupling capacitor.

Partial discharge measurements for a twisted pair of insulated conductors at low pressures in air, argon and helium

Partial discharge (PD) measurements in air, argon and helium, under pressures from 101.3 kPa (760 Torr) down to 0.27 kPa (2 Torr), have been performed for both 60 Hz AC and DC energization. The electrode arrangement is a twisted pair of insulated conductors taken from a standard aircraft wiring harness. The paper describes the physical PD test setup, the electrical connections for AC energization, and specifies the twisted pair arrangement of the insulated conductors. The results are presented in terms of PD current pulse waveforms and their analysis reflecting the effects of pressure and voltage

Partial Discharge Detection for Evaluation of Insulation Integrity in Aerospace Electric Power System Wiring and Components

The paper describes the importance of partial discharge (PD) detection for aerospace electric power system wiring and components in low pressure environment. The relationships between recorded discharge pulse current waveforms and PD electrical characteristics are explained and discussed. Features of a new PD analyzer for low pressure applications are reviewed

Partial Discharge Measurements for a Twisted Pair of Insulated Conductors at Low Pressures -- Pulse Waveform Analysis for Argon and Helium

Partial discharge (PD) experiments in argon and helium have been performed for 60 Hz AC energization, under pressures from 101.3 kPa (760 Torr) down to 0.27 kPa (2 Torr). The electrode arrangement was a twisted pair of insulated conductors taken from a standard aircraft wiring harness. The paper describes the physical PD test setup and electrical connections for AC energization. The results are presented in terms of PD current pulse waveforms and their analysis, reflecting the effects of pressure and voltage.

Electromagnetic noise emission measurements near the Flexible AC Transmission System (FACTS) device at the Sullivan (TVA) station

The expanded application of Flexible AC Transmission System (FACTS) technology to electric transmission and distribution systems frequently provides the best means of insuring the needed levels of capacity and reliability. This paper provides a review of electromagnetic emissions from a FACTS system tested at the Sullivan (TVA) Station. Electromagnetic interference (EMI) emissions from FACTS equipment may vary widely. Some of the data indicate potentially significant levels of emission, while data from other locations may be relatively benign. This variability highlights the need to be aware of the EMI issues when designing and applying FACTS devices to ensure that troublesome levels of emissions are avoided.

Partial discharge characteristics at low pressures in dry air and argon

Characteristics of partial discharges (PD) in two gases (air and argon) under pressures in the range of 0.1 to 760 Torr, and 60 Hz AC energization are discussed for an energized needle grounded plane electrode arrangement. The most significant conclusion of the study is that the frequency content of PD current pulses for all the tests conducted is much lower at low pressures than at atmospheric pressure. In general, the frequency content of PD current pulses at low pressures is outside the detection range of typical commercially available PD equipment.

Low Pressure Partial Discharge Investigation with FEM Modeling for a Twisted Pair of Insulated Conductors

Partial discharge (PD) phenomena with a twisted pair configuration of insulated conductors have been investigated in a low pressure environment. The pressure range was from 2 to 760 Torr. PD waveforms were recorded using a 50-Omega viewing resistor. Representative PD waveforms at various pressures are presented. Three-dimensional two-variable histograms of PD amplitude and rise time vs. phase angle of the 60 Hz source voltage were developed. Visual phenomena of PD manifestation at low pressure were observed in the laboratory. Several two-dimensional cross-section modeling of the twisted pair of insulated conductors were constructed to study the electric field distribution of the electrode configuration. Correlations between the PD waveform characteristics and the physical PD mechanisms were investigated with the help of the finite element method (FEM) modeling techniques.

Partial discharge measurements at low pressures with and without a dielectric barrier

Partial discharge (PD) characteristics in air and argon in the 0.1-760 torr pressure range are reviewed for a needle-plane electrode arrangement. The test setup and various test results (PD inception voltage, waveforms, rise times) are discussed.