Partial Discharge Detection Method Research Articles

A new partial discharge detection method for live UHV/EHV cable joints

AbstractPartial discharge (PD) detection on live UHVEHV power cables and accessories is one of the most important techniques to prevent cable systems from serious difficulties caused by slight errors in joining the cables. A new PD detecting method is proposed in this paper. A resonance‐type partial discharge (REDI) sensor is developed for detecting PD occurring inside the joints of live XLPE insulated cables. This sensor picks up the high‐frequency components of PD current pulses on the surface of live cables, hence the output signals can clearly be observed at the noiseless area (for example, 10‐60 MHZ).This new method was applied to the initial ac breakdown tests with three different types of joints of UHV/EHV power cables. The PD pulse sequence was detected before their breakdown in all cases. The charge quantity and the number of pulses increased tremendously just before the breakdown. In addition, the phase of PD pulse against the applied voltage (ϕ‐q characteristics) changes with time or with the progress of deterioration. According to these experimental results, the REDI sensor can be applied to the insulation diagnosis of live power cable joints.

Development of a method of partial discharge detection in extra-high voltage cross-linked polyethylene insulated cable lines

Deterioration in the insulation performance of extra-high voltage XLPE (cross-linked polyethylene) cables is believed to be attributable to the deterioration caused by partial discharges. After using an XLPE cable to investigate the behavior of partial discharges under various adverse conditions, the authors succeeded in developing a highly sensitive novel method of measuring partial discharge in XLPE cable lines. Partial discharges in a 275 kV XLPE cable live line have been measured using this method. As a result, a detection sensitivity of 1 pC has been achieved. >

Detection of parallel discharges in gas insulated substations

Four methods for partial discharge (PD) detection in gas-insulated substations were considered. Laboratory tests were carried out to determine the efficiency of these methods to detect defects and to discriminate among different defect types. The sensitivity of the methods is compared and the applicability of the methods in the field is discussed. In the laboratory the standard PD measuring method showed a good sensitivity to defects. In the field condition the standard PD measuring method can have a sensitivity much lower than in laboratory, due to the rather high noise level expected. In the laboratory two of the alternative PD detection methods (namely the acoustic method and electrical method including a field probe inside the GIS) have shown a sensitivity to fixed-type defect discharges, while showing less efficiency relative to the mobile particles considered in the study. >

New partial discharge detection method for live UHV/EHV cable joints

Partial discharge (PD) detection for live UHV/EHV power cables and accessories is the most important test on cable systems, to prevent problems caused by minor mistakes in jointing the cable. A new PD detecting method is proposed. A REDI (resonance type partial discharge) sensor was developed for detecting PD occurring inside the joints of live XLPE insulated cables. This sensor picks up the high frequency components of a PD pulse in the noiseless range (for example, for 10 to 50 MHz). This new method was employed to observe the initial AC breakdown tests applied to three different types of joints used in UHV/EHV power cables. PD pulse sequences were observed just before the breakdown in all cases. A PD pulse sequence against the phase of applied voltage (A gamma -q characteristic) changed with time or degree of deterioration of the sample. Results of these experiments show that a REDI sensor can be used for insulation diagnosis of live power cable joints. >

ヨークコイルを用いたワイヤシールド式CVケーブル線路の活線部分放電検出法の開発

This paper describes a new partial-discharge detection method for an XLPE-insulated copper wire-shielded cable line using a “yoke coil.” Partial discharges are measured with the yoke coil which detects the azimuthal component of the current flowing through the copper wires wound on an outer semiconducting layer with a given angle against the axial direction of the cable. The highest detection sensitivity of 2 pC has been achieved at a frequency range of 5 to 20 MHz using a 77-kV 100-mm2 model cable line (200 m in length). It was confirmed that the partial discharge caused by an artificial defect has successfully been detected using the proposed method. In the PD measurement for an actual 77-kV XLPE-insulated live line, the detection sensitivity was 10 pC.

A New Method for Detection and Location of Distributed Partial Discharges (Cable Faults) in High Voltage Cables Under External Interference

Todays partial discharge (PD) detection and location methods in high voltage cables are limited by the influence of external interferences as well as by the type and properties of the cable and by the nature of PD impulses. The problems of the existing methods could be overcome by the development of a new electronic PD detection and location method of high sensitivity and accuracy. It allows the recording and evaluation of partial discharges in HV cables even under the influence of external interference. The accuracy of location is 99.8% yielding a sensitivity down to 1 pC.

Turbine generator ventilation

Detection of partial discharges (PD) is of great importance in the monitoring of high voltage devices and their early fault diagnosis. The ultrasonic sensing is one of the PD detection methods proposed in the literature. Normally, the partial discharge signals are mapped onto the voltage waveform to generate the phase resolved partial discharge or PRPD patterns for the fault type recognition. However, the travel time of ultrasonic signals hinders using a similar process in the ultrasonic PD method. In order to avoid this problem and to improve the ultrasonic PD detection by generating corresponding PRPD, this paper presents a novel method that utilizes ultra-high frequency (UHF) and ultrasonic signals of PD, simultaneously. To show the performance of this method, a circuit is built for ultrasonic PD detection first. In the next step, a wideband antenna is utilized, and its signals are compared with the ultrasonic sensor output to compensate for the PD travel time error. Finally, the PRPD patterns are generated and analyzed for five different configurations. The electrical PRPDs are measured for these cases and compared with the acoustic ones. The experimental results demonstrated in this paper prove the potential of the proposed idea to generate acoustic PRPD for the purpose of PD type recognition.