Miyerkules, Oktubre 12

Guide for Electrical Testing and Inspection

Electrical Maintenance Program and Principle of Electrical Testing

Electrical Maintenance Activities Fall into three General Categories:

I. ROUTINE MAINTENANCE

  • Activities that are conducted while equipment and system are in service. These activities are predictable and can be scheduled, staffed and budgeted. Generally this are schedule on a time –based, run time meter or number of operation schedule.

Examples: 
  1. Visual Inspection 
  2. Infrared Scans
  3. Cleaning
  4. Functionality Test
  5. Lubrication
  6. Oil Test
  7. Governor and Excitation System Alignment

II. MAINTENANCE TEST
  • Activities that involved the use of electrical test equipment to determine electrical equipment RELIABILITY in an offline state.

Examples: 
  1. Insulation Resistance Test
  2. Breaker Trip Testing
  3. Alternating Current High Potential Test
  4. High Voltage Direct Current Ramp Test
  5. Battery Load Test

III. DIAGNOSTIC TESTING
  • Activities that involve use of test equipment to access condition of equipment after unusual event such as faults, fire or equipment failure/repair/replacement or when equipment deteriorate is suspected.

Examples:
  1. Turns Ratio
  2. Core Ground Test
  3. Insulation Resistance Test
  4. Insulation Power Test
  5. Winding or Contact Resistance Test

DIFFERENT KINDS OF IDENTIFICATION OF ELECTRICAL HAZARDS

1. Insulation Resistance Test
  • Resistance (in megohms) offered by the insulation to an impressed direct voltage. Insulation Resistance is NOT a definite measure of the voltage an insulation will stand, its is an indicator of the suitability of the insulation for continued service.

Application of Insulation Test Method



2. Dielectric Absorption
  • The time resistance test is independent of equipment size and temperature. It compares the absorption characteristics of contaminated insulation with the absorption characteristic of a good insulation. The test voltage should be applied over a 10 minute period with the data recorded every 10 seconds for the first minute there after. The interpretation of the of the slope of the plotted graph will determine the condition of the insulation. A continuous increase in resistance in the graph indicates a GOOD Insulation. A flat or downward curve indicates cracked or contaminated insulation. 

3. Polarization Index
  • The steepness of the dielectric absorption curve taken at a given temperature indicates the relative dryness of the insulation.

Polarization Index = R10 / R1 = The value must be more than 1.

where:
R10 = MegaOhms at 10 minute reading
R1 = MegaOhms at 1 minute reading

NETA STANDARD / IEEE 43-2000:
Polarization Index should be higher than 1


4. Insulation Power Factor Test
  • The purpose of this test is to determine the state of dryness of the winding and insulation system and to determine the power factor for overall insulation, including bushing, oil and winding. It’s a measure of the ratio of power losses to the volt amperes applied during the test. The power factor obtained is measure of watt lost in the transformer insulation system including the bushing. 

The Power Factor should not exceed 0.5% at 20 degrees Celsius


5. Winding Resistance Test or Contact Resistance Test
  • This is to check the loose connections and broken strands. The most accurate method is to allow the transformer sit de-energized until temperatures are equalized. Take the reading from the top of each bushing to neutral for wye and across each pair of bushing for delta. Result are compared to other phase in wye connection or between pairs of terminal on delta connected winding to determine if a resistance is too high. Resistance can also be compared to the original factory measurement. Investigate and deviate from adjacent pole or similar equipment / devise by more of 25% of lowest value.


6. Transformer Turn Ratio Testing
  • TTR detects shorted turns which indicates insulation failures by determining if the correct turns ratio exist. Shorted turns may result from short circuit or dielectric (insulation ) failure. Measures are made by applying a known low voltage across one winding and measure the induce voltage on the corresponding winding. The voltage ratio obtained by the test is compared to the nameplate voltage ratio. The ratio obtained from the field test should agree with factory data, within 0.5%. New transformer of good quality normally within 0.1%.

22 comments:

I have enjoyed reading your articles. It is well written. It looks like you spend a large amount of time and effort in writing the post. I am appreciating your effort. .
Electrical Testing and Tagging

Hi mahesh! Thanks for that comment! You are the first one! :) Yeah, I did. I'd really like to share the knowledge in Electrical Safety so that accidents could be reduced. So, just browse here and have fun! Thanks! :)

I just wanna thank you for sharing your information and your site or blog this is simple but nice article I’ve ever seen i like it i learn something today.

electrical protective relay testing

Thanks for sharing such a great post about Electrical Testing. Very helpful.

This is an informative post review. I am so pleased to get this post article. I was looking forward to get such a post which is very helpful to us. Keep it up. . I know something information, to know you can click here
Test and Tag brisbane
rcd testing services brisbane


This site is good because they give us a new thing and new ideas and new topic how good all of they are we should appreciate them because of these good thing.
I know something information, to know you can click here
Test and Tag brisbane
rcd testing services brisbane

Test and Tag Brisbane is committed to providing appliance safety solutions whilst delivering the highest level of quality service excellence.
We offer a large range of electrical testing services.
This is a authorized requirement that all these types of appliances are tested consistently in order that These are electrically Risk-free for use.
you can try this out

Test and Tag
Test and Tag brisbane

we can also help to save you money through better electrical wiring and more efficient cooling of your property.
Even if you already have one of the top of the line air conditioning Brisbane systems,
there may be a way we can improve on what you already have.
Let us know what you have and the kind of business you have and we will consult you on whether you have the best system or not.

electrical services brisbane
brisbane electrical services

Servicing customers in need of new electrical installations, repair and maintenance and protection inspections.
Our Electric powered contractors are going to be Completely ready to aid. We provide specialized provider and help, be it commercial or residential.


electrical services brisbane
brisbane electrical services


If you want to test proffesionally, you must show up at an accredited test and tag study course recognised via the Queensland Electrical Safety Business office
and obtain a restriced contractors license (Notice – this isn’t similar to a limited electrical license).
Call us or the QLD Electrical Protection Business For more info.

Test and Tag
Test and Tag brisbane


Tes and tag would want to be the organization responsible for this For many years to come.
The moment entered into our database we do many of the function.
Nearing the expiration within your asset tags we’ll Make contact with you and book a suited time for you personally.
Provided that you’re our consumer, your Test and Tag will be our accountability.


Test and Tag brisbane

It's important to remember that when you're testing and tagging a laptop, you're basically doing it in two parts.
It includes testing both the IEC lead and laptop charger, with each one receiving its own test tag. The laptop itself...

Test and Tag

Electroy can help you to save a lot of money with things like the best solar panels Brisbane has to offer.
If you have decided to invest in the solar Brisbane homes and offices already depend on,
we can provide you with the help you need. We will install everything for you so you are getting all
the electricity you need without causing any structural damage to your home.



electrical services brisbane

Brisbane Electrical Contractors is really a household owned and operated electrical contracting small business that has in depth field working experience.
At Electrician Within a Hurry - Brisbane Electrical Contractors, we make improvements to the caliber of our customers lifestyles by providing prompt,
good quality and ethical electrical providers



brisbane electrical services


You need target visitors for your website this may try some for freeto you?
we have a VERY POWERFUL and POPULAR company now lets try to know their traffic service.
I am so glad they opened their traffic system back up to the public! Check it out here

brisbane electrical services

Test and Tag Brisbane is dedicated to making sure that the Independent Test And Tag has minimal impact on your business.
In the event we have a company in Brisbane and want to have your online business detailed here then
increase your online business towards the guideline.please see more,

Test and Tag brisbane

Electrical Testing and InspectionWe are leading electrical inspection and testing company for Fixed Wire Testing and Installation. We are located in Liverpool visit/call us at 07851 951 553

electricians LiverpoolYou can depend on DTF Electrical Contractors Limited for your electrical contracting projects. So if you have a project you’d like to discuss, give us a call. We can take on projects of any size or duration, from 1 day contracts to ongoing contracts. There’s no obligation and it will give you a clear idea of how we could help.

hello

your blog is very nice i like it.. its a very usefull blog

Emergency Electrician Liverpool :- Specializing in both Electrical and Plumbing Services AUSSIE AEP is one of the finest Electrical and Plumbing Services in Sydney.

including those that affect private sector investment in this emerging business activity. Used Lab Equipment Rental

Electrician Perth, KNP Electrics offer a range of Electrical Services to Perth & surrounding suburbs. With a range of products for Commercial or your Home
electrical maintenance perth

Mag-post ng isang Komento

Share

Twitter Delicious Facebook Digg Stumbleupon Favorites More