demo report for partial discharge testing new revised malaysia

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Hoestar Reliability Instruments Sdn Bhd (693347-T)CT-04-07, Subang Square Business CentreJalan SS 15/4G, Subang Jaya47500 Petaling Jaya, Selangor Darul Ehsan, MalaysiaEmail: [email protected]: 02-03-56326832 Fax: 02-03-56376832

PARTIAL DISCHARGE MEASUREMENT SAMPLE REPORTFOR ABC COMPANY PTE LTD

ON 19TH NOVEMBER 2004

Report Prepared : 19th November 2004

Tested By : Lim Chee Meng Certified Infrared Thermographer

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COMPANY PROFILE

INTRODUCTION

• We are a specialist company providing Equipment Condition Inspectionservices for the benefits of our customers in Singapore and the region for thepast 10 years. We have been successful in working with our clients onproviding a one-stop solution to their various needs and problems in ConditionMonitoring and Maintenance. We can provide non-invasive testing of air-conditioning systems, mechanical and electrical installations using provenmethods of infrared, partial discharge testing, vibration analysis & motorsignature test for customers at reasonable cost. Also, we have been involvedin the fight against SARS by providing SARS fever detection services tovarious organizations in Singapore.

• To further enhance our ties with customers such as you and to further developour infrared, vibration analysis and other reliable condition monitoringtechniques, we would be happy to work with you by providing the relevanttraining and sharing of our experience and expertise necessary to help youextend your expensive equipment life. We can detect early problems inequipment before damage occurs, and provide other support services throughthe use of innovative techniques and equipment. All these have been donewith one very important objective of assisting you in managing your costlyequipment and reduce downtime due to equipment failure and reduceexpensive replacement of equipment.

• The benefits to you, our valued customers, are immeasurable. Not only do youget see the results of our work by having to spend less on equipmentmaintenance but also machine utilization is maximized as well.

OUR VISION• To be Asia’s leading Equipment Condition Inspection Specialist and other

related services provider by providing high quality value-added products andservices to meet the rising needs of our customers in the region.

OUR MISSION• To provide the best and reliable inspection service to customers in the region.

They are as follows:-• Infrared Thermography Inspection for the Low Voltage Electrical System,

Building Façade and Mechanical Equipment• Partial Discharge Testing with Spectrum Analyzer for High Voltage

Equipment of more than 3.3KV without the need to shut down• AHU Performance Management Program – Condition Monitoring with

Maintenance• Vibration Analysis and Diagnostic for rotating equipment.• Motor Signature Test for Low Voltage Motors of less than 600V• EMI (electromagnetic inference) Measurement & Solutions

OUR BUSINESS

• Power Quality Analysis & Solutions

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Name of the Company

Managing Director

Hoestar Inspection International Pte LtdHoestar PD Technology Pte LtdHoestar Reliability Instruments Sdn Bhd

Leong Weng HoeCertified Thermographer Level IICertified Vibration Specialist Level II

Our Place

Of

Business

SINGAPORE – Established 3rd July 1991• 5A Siang Kuang Avenue, Singapore 347923

Tel: 64881603 Fax: 62819477

MALAYSIA – Established 1st June 2005• CT-04-07, Subang Square Business Centre

Jalan SS15/4G, Subang Jaya47500 Petaling JayaSelangor Darul Eshan, MalaysiaTel: 03-56326832 Fax: 03-56376832

Staff Strength 12 with 4 Certified Thermographers

Equipment Used ⇒ Inframetrics PM 350 – 1 in No. (for Infrared Inspection)

⇒ FLIR PM675 – 1 in No. (for Infrared Inspection)

⇒ MTech PM200 – 1 in No, (for Infrared Inspection)

⇒ Ultrasound SDT 100 – 1 in No. (for Ultrasound Inspection &Partial Discharge Testing in HV equipment)

⇒ Partial Discharge Analysis proprietary Analytical Software

⇒ Spectrum Analyser – 1 in No. ( for Partial Discharge Testingin HV equipment)

⇒ Entek IRD DataPAC 1500 Analyser /Data Collector - 1 inNo. (for Vibration Analysis Inspection)

⇒ Motor Current Analyser Kit – 1 in No. (for Motor AnalysisInspection)

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To provide:a) Advanced Vibration Diagnostics and Motor Signature

Analysis of rotating equipment e.g., AC motors, turbines, compressors, Chillers, Pumps

b) Advanced Infrared Thermography of:• Electrical System:

i) LV Transformersii) Sub Station 3.3KV & belowiii) Main Switch Boardsiv) Bus Ductsv) Chiller Switch Boardsvi) Sub Boards

• Building:i) Facades – falling tiles moisture ingress and energy lossii) Roof Inspection for leaks

• Mechanical Equipment:i) Furnacesii) Refractoriesiii) Chiller & Steam Pipesiv) Rotating Equipment – bearings & motorsv) Heat Exchanger – corrosion leak detection

c) To provide Partial Discharge Testing using Ultrasound &Spectrum Analyser for High Voltage Equipment of morethan 3.3 KV without the need to shut down. Use of PD Testto check Oil Quality before Oil Test.

Services

d) AHU Performance Management Program – ConditionMonitoring with Maintenance.

Training a) Basic and Advanced Vibration Analysisb) Infrared Thermographyc) Precision shaft alignmentd) In-house training for Vibration Analysis, Infrared

Thermographye) Partial Discharge Testing Certification.

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Partial Discharge Testing-DO YOU NEEDIT?

Oct 2002

Written by Leong Weng Hoe,[email protected]

HOESTAR INSPECTION INTERNATIONAL PTE LTD

INTRODUCTION:A number of users with high tensionequipment such as HV Switchgears,transformers and motors have rightly orwrongly assume that Partial Discharges do notoccur in their systems. However from ourwork done ,it can be shown that partialdischarges do and are occurring in all HVequipment though their magnitudes are usuallyvery small .However they can change becauseof the following factors;a)Environmentb)Manufacturing Defectsc)Electrical, Thermal and Mechanical Stressesd)Poor maintenancee)Poor equipment design

From our field work there are many instancesof partial discharge occurring due to the abovefactors. As a result, massive losses hadresulted from equipment failure. Most of thetime this can be prevented if the correct andproper testing had been used.

1]Yu Ming and S Birlasekaran, “ Characterization ofpartial discharge signals using wavelet andstatistical techniques”, Proc. of the 2002 IEEEInternational Symposium on Electrical Insulation,Boston, MA, USA, April,2002, pp 9-13.

Partial Discharge TestBecause of the problems mentioned above,Hoestar Inspection International Pte Ltd inconsultation with A/Prof S Birlasekaran, anexpert in Partial Discharges in High VoltageDistribution,have developed a reliable,accurate and effective method in detecting thepresence of partial discharges . This techniquecan identify the various types of dischargepresent and determine their severity. This isdone through the use of proprietarysoftware and hardware. With a powerfulscopemeter and probe, waveforms of thepartial discharges present are converted tospectrums and analysed. With Spectrum andWaveforms Analysis, we are able to:-

i. Identify type of discharges present

ii. Determine severity of the discharge

iii. Determine true magnitude of dischargepresent as interference is removed

iv. Verify the measurements produced bythe PDL-01

v. Verify the measurements produced byUltrasound Detectors

vi. Detect any discharges in noisyenvironment where UltrasoundDetectors cannot be used.

vii. Detect and identify early onset ofdischarge in HV equipment.

viii. Locate the source of discharge.

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DIAGNOSTIC PARTIAL DISCHARGE MEASUREMENT SUMMARY

1. The Diagnostic Partial Discharge Measurement was carried out for ABC COMPANY Pte on 10th

December 2004. The details of the PD Measurement readings are indicated in the attached report.

2. The method of analysis being used will provide a more comprehensive understanding of partialdischarge detection and analysis as compared to previous analysis. Please note that the methodsused here are in conformance with international acceptable practice for partial discharge analysis.

Yorkshire SWGR 22KV, Main Substation, Panel 11

In the course of our inspection, hissing sound was heard emanating from the rear of the Panel 11in the Main Substation. Thereafter a thorough measurement was made to verify if the sound isthe result of partial discharges occurring on the conductors within the switchgear panel. Pleasesee details in report.

Would suggest an urgent shutdown for service as breakdown voltage could occur when the rightconditions are present.

**********

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DIAGNOSTIC PARTIAL DISCHARGE MEASUREMENT FOR HIGH TENSION SWITCHGEAR

Date : 10 December 2004Page : 1 of 1

Client : ABC COMPANY

Time : 1500Hrs Location : Main Substation Floor : 1st StoreyVoltage : 22 KV Brand / Type : Yorkshire Switchgear / Oil Dry

Test Instrument – Partial Discharge Analyser

HT SWITCHGEAR PANEL

BACK

Environmental Reading:• Location of Sensor

Partial Discharge Measurement (mV)BACK

Panel No.

T BStatus

Panel No. 11 234 800 X

Legend: = Acceptable Level X = Unacceptable Level

NOP = Not Operating

Remark:

• T

• B

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Customer ABC COMPANYDate 10 /12/ 2004 Time 15:00 PMLocation Main Substation Level 1st StoreyEquipment 22KV SWBD Panel 11 Brand / Type Yorkshire / Dry Type

Remarks : No significant cavity discharge detected for Panel 12 during thismeasurement.

Remarks : Corona discharges detected with some pulses occurring at very highmagnitude.

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Customer ABC COMPANYDate 10 /12/ 2004 Time 15:00 PMLocation Main Substation Level 1st StoreyEquipment 22KV SWBD Panel 11 Brand / Type Yorkshire / Dry Type

Remarks: Significant Corona Partial discharges are detected within this panel.

Corona

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Equipment: Yorkshire YSR6 Switchgear 22kV. Main Incoming

Rear PanelBYR

Cab

A

B

Skirting

TyPD

Section A

Skirting

Conductor

Discharge present betweenskirting & cable insulationdue to dust ingress in gap.

Skirting

Plan View

Charesu

3 core cable joint

Terminations

le

pe of discharge: Corona max magnitude: 16V

Section B

Gap ~ 0.5mm

rring found on surface as alt of corona discharge

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HIGH CORONA PARTIAL DISCHARGE

CORONA DISCHARGE @ 21mV,25.11 MHZ DETECTED for 22 KV SWITCHGEAR

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CAVITY DISCHARGE 6.6 KV CABLE 3 CORE

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Transformer – Surface Discharge

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Customer ABC Company Pte LtdDate 12 / 10 / 2005 Time 1713 hrsLocation Arc Furnace Room Level 1st StoreyEquipment 33 KV Reactor Brand / Type - / Oil

Remarks : Minor partial discharges on the corona (derive from the pattern below) are detectedwithin this transformer. The max. PD magnitude for 1 pd pulse is 1726mV aftereliminating the surrounding noise.

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Remarks : Density of the Partial discharges on corona (der above with max. number of pulses detected at 5

ive from the pattern above) are shown1

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PD PAC Spectrum AnalyzerSpecifications

Description PerformanceCasing (Weight)Trolley (Weight)(Optional)

Approximately 13 kgApproximately 14 kg

Casing (Dimensions) Trolley (Dimensions)

L (49),W (28), H (10.8) cmL (51),W (50), H (91.3) cm

Casing material Steel casing

Electrical Power Input 2 X laptop battery (12V, 10 AmpHr)1 X lithium battery (16V, 8 AmpHr) for internal apparatus1 X metal hydride (12V, 1.4 AmpHr) for PD sensor

Acquisition Signal inputs ±25 mV to ± 25 V input range

Digital Signal Recording Wideband pulse measurement (100Mhz)Sampling rate 100MS/sLarge internal storage buffer (32MB)40 GB hardisk with 3 USB ports for greater storagecapability

Computing and processingunit

Ultra fast 1.7Ghz Centrino laptop, 2M cache & 512M DDR2 RDual Batteries operation for longer operating timeFast Data PCI transfer rate (32MB/S)

Sensors 1) Capacitive sensor 100 MHz bandwidth. Ultra sensitive to detect PD signal as low as 2.5mV withamplification

2) High Frequency Current Transformer (HFCT) – Output sensitivity in 0.5 V/A Maximum current (rms) – 5A Rise time – 0.7 ns High cut-off frequency (-3db) – 500 MHz

Software Data Acquisition software (exe file)Data analysis software (exe file)

All specifications are subject to change without prior notice

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NON-INTRUSIVE PARTIAL DISCHARGE MEASUREMENTS

1. INTRODUCTION

Partial discharges in high voltage metal-clad switchgear or transformers can result incatastrophic failure of the individual plant and in some cases of the substation. Therefore, therehas been a need for detection and location of the damaging discharges without the plant orsubstation being taken out of service. The conventional partial discharge detection techniquerequires either the use of Infrared Thermography or Ultrasound which requires the panels to beopened in order to see any thermal anomaly generated by Partial Discharge activity or to hearthem.

The PD Pac has been designed to fulfil this important requirement.

The PD Pac uses the principle of ElectroMagnetic Wave (EM) measurement. The PD Pac is aportable instrument used to survey high voltage switchboards and transformers while ‘live’without endangering the lives of the PD Specialists.

2. ELECTRO MAGNETIC WAVE MEASUREMENT (EM) TECHNIQUE

If a partial discharge occurs in the phase to earth insulation of a conductor in a high voltagesystem such as metalclad switchgear, a Partial Discharge current pulse will flow on the surfaceof the conductor and the metal cladding. This current will generate an EM wave which willpenetrate through the metal cladding to be detected by the EM sensor of the measuring system.

Advantages of TEV Technique:-

• Non-invasive diagnostic technique• Measurement can be made on live equipment• No switching of power system is required• No high voltage test source is required• No need for a ‘sanction for test’

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Figure 1 is a simplified cross section showing just one phase of a high voltage busbar with agasketed joint on the left hand side.

Figure 1 : Transient Earth Voltage Detection of Partial Discharge Activity.

Electromagnetic Sensor (EM – Sensor)

When partial discharge occurs, Partial Discharge (PD) of very short duration (in a fewnanoseconds) current pulses will flow along the metal cladding or on the skin of the conductor.This current will then generate both electric or magnetic field and emits electromagneticradiation known as Electromagnetic wave (EM wave). This EM wave will either penetratethrough the metal cladding or propagate through an opening in the metal cladding.

When Partial Discharge is sensed using this Electromagnetic sensor, this EM wave will beconverted to a voltage signal with a few nanosecond rise time and an amplitude from milivoltsto volts.

In conclusion, this electromagnetic sensor basically senses for EM wave and acts as a antenna todetect the radiated EM radiation.

PD PAC & MONITOR

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3. CONCLUSIONS

The EM Wave technique is designed for use on metalclad high voltage switchgear andtransformers from 3.3KV above containing compound, oil or air insulation. With this method,the higher the voltage the greater is the distance of detection. Therefore it is suitable for PartialDischarge detection in outdoor or indoor high voltage applications.

As the EM probes used is sensitive to micro pd discharges, the test can be used to determine thehealth of high voltage equipment early before damage occurs. Also it will help engineers todecide which equipment is in need of service thus saving companies from downtime losses. Infact if servicing is really warranted, a pre & post pd inspection will go a long way in preventingdamage which may occur due to human errors or cavity discharges which is usually notdetectable during normal servicing. However, Partial Discharge Test is in no way replacecalibration of protection devices for high voltage equipment.

From numerous site tests carried out, a severity table for determining the condition of highvoltage equipment has been developed to help electrical engineers decide on the next course ofaction to be taken before failure occurs.

Finally, with this test, we can measure the condition of High Voltage equipment while it is inoperation without the need to open the panels or shutting it down.

demo report for partial discharge testing new revised malaysia

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