C. C. Yii

Comparison between Parameter of Single Core Unarmoured Aluminium Conductor 6.35/11 kV Underground Cable for Partial Discharge Measurement Using EMTP-ATP Software

Partial Discharge (PD) is one of a symptom in the underground cable before the fault happens.This paper concerned with estimation and detection problems related to PD phenomena in buried underground cables. The Rogowski coil has been implemented to analyze this symptom. The various sizes of nominal cross-sectional area cross-linked polyethylene (XLPE) cable with 6.35/11 KV single core unarmored aluminum conductors that follows Nexans manufacturer datasheet based on design standard IEC 60502 has been used in the simulation using Electromagnetic Transient Program-Alternative Transient Program (EMTP-ATP) software. The Lumped parameter is used for the Rogowski coil sensor model. Meanwhile, for Double-end measurement using J-Marti model is designed to evaluate the parameter changing in the measurement.Based on the measurement, the value of amplitude voltage and current is proportional increase depends on the size of cross-sectional area of conductor XLPE cable.

Effect of unshielded and shielded Rogowski coil sensor performance for partial discharge measurement

This paper presents the analysis of constructed shielded Rogowski coil (RC) sensor for partial discharge (PD) measurement. The RC sensor with rectangular shape has been designed in order to compare the performance unshielded and shielded type in term of sensitivity. Solidwork 3D CAD software has been used to design the core of RC sensor with their casing. Marker Board Replicator 2X 3D printer is used to print the design. An experiment has been conducted to evaluate the difference performance of unshielded and shielded RC sensor with amplitude range PD signal between 1 V to 5 V respectively and the frequency is fixed to 1 MHz. The difference terminating resistance has been installed to the RC sensor too. From the experiment, the percentage average losses of unshielded and shielded RC sensor from 1 V to 5 V at 14.48 % is achieved. The low level of PD signal is challenging to be detected by the RC sensor. The terminating resistance of the coil is a part of parameter which can improve the performance of RC sensor.

Three-Point Technique for Partial Discharge Location on XLPE Armoured Underground Cable

Recently, a new partial discharge location technique called three-point technique had been introduced to locate partial discharge on underground cable. It is the improvement of double-end technique. In this paper, the mathematical formula of three-point technique had been simplified from previous research. Alternative Transient Program (ATP) was being used to simulate both double-end and three-point technique. The results of the simulation were compared and analysed based on the accuracy, cost of implementation and algorithm complexity of the technique. Three-point technique had shown significant improvement in the accuracy of partial discharge location on underground cable.

Multi-end PD location algorithm using segmented correlation and trimmed mean data filtering techniques for MV Underground Cable

Medium voltage underground cables are widely used in urban area as distribution power lines due to their advantages over overhead cables. Underground cables may suffer from partial discharge because of insulation degradation after certain period of time. In this paper, an improved multi-end partial discharge location algorithm called segmented correlation trimmed mean algorithm is proposed. The algorithm uses segmented correlation technique and trimmed mean data filtering technique to enhance the accuracy of partial discharge location algorithm. The algorithm had been tested in MATLAB environment which consists white Gaussian noise. First, discrete wavelet transform is carried out to suppress noisy signals. Next, segmented correlation technique is applied to the de-noised segmented partial discharge signals. Segmented correlation technique has manipulates partial discharge signals by performing cross correlation process on segmented partial discharge signals in order to reduce memory usage and algorithm execution time. Lastly, trimmed mean data filtering technique is applied to the estimated partial discharge location values to estimate new partial discharge location value. Trimmed mean data filtering technique does statistical process control on estimated partial discharge location values in order to minimize the error of estimated partial discharge location. The segmented correlation trimmed mean algorithm had been compared with the existing multi-end correlation-based algorithm. The result shown that the segmented correlation trimmed mean algorithm has better accuracy than multi-end correlation-based algorithm.

Techniques on partial discharge detection and location determination in power transformer

Insulation failure has been identified as one of the main reasons for transformer breakdown. As one the most important assets in the high voltage system, the loss of a power transformer will cause significant effects to consumers and on the system. The condition of the insulation can directly be correlated to the presence of Partial discharge (PD). Therefore, the ability to accurately detect and analyse the information from PD could be the answer to avoid catastrophic breakdown. On top of that, the capability to pinpoint the location of the PD source would enable swift preventive action to be taken. Several methods have been researched and developed in those two areas. This paper will discuss such techniques. Included in the discussion is an introduction to some less conventional techniques such as optical and ionising emission detection.

Geometrical Shapes Impact on the Performance of ABS-Based Coreless Inductive Sensors for PD Measurement in HV Power Cables

In this paper, a series of investigations on sensitivity and bandwidth for four types of Rogowski coil (RC) sensors was demonstrated. The proposed RC sensor design using acrylonitrile butadiene styrene material carries the advantages, such as lighter weight, robust, and higher temperature resistance. The prototype development first was carried out with the assistance of Solidwork 3D computer aided design software and MakerBot 2X 3D printer. Subsequently, the sensors were modeled and simulated using electromagnetic transient program-alternative transient program software environment based on the lumped parameter identification. A single-end measuring technique was used to locate the PD signal on the three-phase medium voltage underground cross-link polyethylene insulated power cable with a 240-mm2 nominal area copper conductor. In order to verify the results achieved from the simulation, an experiment was carried out. This experiment was repeated concurrently for each design of the RC sensors. In order to achieve the best PD detection, the precise selection for the best sensor is paramount. In this case, the results indicated that certain geometrical shape performed better with regard to the detection of the PD signal.

Multi-end partial discharge location algorithm based on trimmed mean data filtering technique for MV underground cable

A remarkable challenge in online partial discharge monitoring is to extract desired partial discharge signal from excessive noise caused by the operating cable. Wavelet based de-noising technique can be utilized for noise suppression. However, the wavelet based de-noising techniques ability to fully suppress the non-constant level of noise is limited. Therefore, trimmed mean data filtering technique is applied in partial discharge location algorithm for statistical analysis. In the process of creating trimmed mean partial discharge location algorithm, multi-end partial discharge location algorithm is restructured by adding trimmed mean data filtering technique. Both multi-end partial discharge location algorithm and trimmed mean partial discharge location algorithm had been tested for their performance. In the performance test, noise is modeled and added into the simulated partial discharge signals to enhance the similarity of simulated partial discharge signals with real detected partial discharge signals. Discrete wavelet transform de-noising technique is used for suppressing various level of simulated noise in partial discharge signals. The test result showed that trimmed mean partial discharge location algorithm enhances the accuracy in estimating partial discharge location under noisy environment.

Evaluation of Rogowski coil sensor performance using EMTP-ATP software

Detection and measurement of partial discharge (PD) are important to monitor the insulation life in high voltage (HV) power equipment. This paper presents an electrical detection method which is Rogowski coil (RC) has been chosen as a measuring sensor to detect and measure the PD signal. Series of investigations on sensitivity and bandwidth for four types of RC using electromagnetic transient program-alternative transient program (EMTP-ATP) software was demonstrated. A single-end measuring method is used to locate the PD signal on three-phase MV underground cross-link polyethylene (XLPE) cable with 240 mm2 nominal area of copper conductor cable. An experiment was conducted in order to verify the simulation results. The precise selection of RC sensor based on the simulation and experimental results was compared with the previous design of researchers in term of sensitivity and bandwidth. In this case, result indicated that the new design of RC sensor performed better plays a vital role in detecting PD signal.

Denoising technique for partial discharge signal : A comparison performance between artificial neural network, fast fourier transform and discrete wavelet transform

This paper presents de-noising of PD signal using three different techniques; ANN, FFT and DWT. The objective of this paper is to yield the PD signal from the disturb signal which is the combination of PD and noise signal. These signals are generated using EMTP-ATP simulation environment. This research used the straightforward procedure in the de-noising technique. The accuracy of the de-noising is based on the calculation of SNR. The result of this research shows ANN is the best de-noising technique as the calculated SNR is the highest with 0.635938, followed by FFT technique with SNR of 0.452903 and lowest SNR is DWT with −0.154054.