High voltage transformer - 138kv power transformer
This article is about the one of the high voltage class transformer: 138kv power transformer. About the basic spec, the accessories, the test and ship.
There have different voltage classes, one is low voltage, second is medium voltage, third is high voltage.
As low voltage transformer, their voltage class can is 10 kv class, 20 kv class, they are distribution transformers.
As medium voltage transformer, their voltage class is 30 kv class, 35 kv class, they are substation transformer.
For the 66 kv voltage class and 69 kv voltage class, much higher class, include 115 kv voltage class, 138 kv voltage class, and 230 kv their should be high voltage transformer, we also call them power transformers.
Pad-mounted Transformer
Dry-type Transformer
Oil immersed transformer
Table of Content
What is a high voltage 138kv power transformer?
A high voltage transformer need to have the following spec tech.
1) . The Altitude of the high voltage transformer:
Maximum altitude can be – 100 meters (about 330ft.)
2) . Short Circuit Withstand of a high voltage transformer:
The high voltage transformer shall be designed to withstand the duration of 2 seconds in short circuit condition.
In order to allow for possible flash over of the neutral grounding resistor, the high voltage transformer shall be capable of withstanding the mechanical and thermal stresses for a single line-to-ground short circuit with a solidly grounded neutral on the secondary side.
3) . Temperature Rise for a high voltage transformer:
The average temperature rise of any winding above ambient temperature, measured by resistance, shall not exceed 65 °C.
4) .Forced Air Cooling of a high voltage transformer
The high voltage transformer shall include two stages of forced air-cooling to give ratings 133% of the selfcooled rating. The following minimum equipment shall be included:
a) Adequate capacity in all current carrying parts and bushings.
b) Cooling fans, to operate from 208/120V three phase, 60 Hz supplied by purchaser or from the station service power transformer.
c) Fan control contactors and hand-off-auto selector switch. Contactor to be complete with one extra normally open contact wired to terminal blocks for purchaser’s use.
d) Contacts on transformer winding temperature indicator for fan control.
You may interested in Oil Type transformer – DAELIM BELEFIC
What is the accessories for the high voltage 138kv power transformers?
1). Surge Arresters
Station class, surge arresters metal oxide type shall be provided and mounted on brackets on the primary side of the transformer. Arresters shall be connected to a ground pad welded to the top of the transformer tank. Surge arrester shall be rated 120kV with MCOV of 98kV.
2) . Indicating-type shut-off valve in liquid line between conservator and main tank(conservator type units).
3) Non-dehydrating breather (conservator type units).
4) Lifting, moving and jacking facilities capable of handling the total filled weight of the transformer.
5) Manholes or hand-holes for tank access.
6) Pressure relief device, self-reset, with shroud to deflect hot oil away from the front of the high voltage transformer.
7) Liquid level gauges with preset alarm contact.
8) Liquid temperature gauges with drag hard for maximum indication and preset fan control, alarm and trip contacts. Drag hand with ability to reset from ground level.
9) Winding temperature gauges with drag hand for maximum indication and preset fan control, alarm and trip contacts. Drag hand has ability to be reset from the ground level.
10) Liquid drain valve and sampling valve.
11) Valves (2” NPT) for connections to liquid treatment facilities so that liquid may be filtered and re-circulated in the transformer.
12) Grounding pads, predrilled and tapped, and welded on the base or on the tank wall. One ground pad shall be located towards the extreme right and on the side of the low voltage bushings and the other diagonally opposite.
13) Anti-condensation heater in control cabinet.
14) Vacuum/pressure gauge (sealed tank type units) with facilities for isolating the gauge so that it may be removed for calibration without draining the tank or allowing moisture into the tank when the gauge is removed.
15) Gas sampling valve.
16) All gauges visible from ground level.
17) Off-circuit tap position indicator and all gauges clearly visible from ground level.
18) Diagram instruction nameplate, stainless steel.
Know more about One article to understanding more about earthing transformer
How do you make a high voltage transformer?
1）High Voltage Terminations of the high voltage transformer
The 138kV windings shall be brought out through cover-mounted bushings. The bushings shall be oil filled condenser type, rated 154kV, 650kV BIL, complete with suitable threaded stud connectors Bushings shall include a capacitor tap for testing.
2) 13.8kV Voltage Terminations of the high voltage transformer
The 13.8kV windings shall be brought out through cover-mounted bushings located 180 degrees with respect to the high voltage bushings. The bushings shall be rated 15kV, 110kV BIL suitable for 2x1c -1000MCM/phase cable connections.
3) Neutral Termination of the high voltage transformer
The neutral point of the 13.8kV winding shall be brought out through a cover-mounted bushing. The neutral connection and bushing shall have minimum current rating of at least 50% of that of the self-cooled (ONAF) transformer rating.
4) Grounding Resistor of the high voltage transformer
The transformer shall be complete with a grounding resistor, stainless steel type, 8kV, 200A for 10 seconds, 40 Ohms, completely assembled in a screened outdoor enclosure and mounted on the side (or top) of the transformer, The resistor shall have a continuous current rating of at least 10% of the short time (10 second) rating. All connections from the resistor to the 13.8kV neutral bushing and to the tank ground shall be provided.
5) Off-Circuit Taps of the high voltage transformer
Four only 2.5% full capacity taps, 2 above rated voltage and 2 below, shall be provided in the13.8kV winding.
The tap position switch shall be externally operated, with provision for padlocking, and is to include a nameplate specifying that the high voltage transformer must be deenergized before operating the switch.
6) On-Load Tap Changer (OLTC) of the high voltage transformer
The high voltage transformer shall be complete with three-phase type on-load tap changing equipment 21 steps with 10 above and 10 below to automatically provide voltage compensation of +/-10% of the 138kV winding for variations in supply voltage to the 13.8kV winding and. All taps shall be full capacity. The OLTC oil-filled compartment shall withstand full vacuum.
7) Nameplates
All relays, selector switches, breakers, etc. located within the control cabinet shall be clearly identified with laminated plastic type nameplate and this identification shall agree with that on the schematic and wiring diagrams.
Which test for high voltage transformer need to do?
Daelim will do the routine tests in our factory before shipping, after the all the test passed, we will send the test report to the customer to confirm. All things have no problem, we will deliver them from our factory.
Factory routine tests are as follow:
• Resistance tests of all windings
• Ratio tests on the rated voltage and all tap connections
• Polarity and phase relation tests at rated voltage
• No load loss at rated voltage
• Exciting current at rated voltage
• Impedance and load losses
• Applied voltage test
• Induced voltage test
• Full wave impulse test
If the customer has special requirements on the test items, such as temperature rise test, lightning impulse test, they will have extra costs.
The customer should inform Daelim that they need these tests, and Daelim will add the cost to our quotation list. Or we will do the standard factory routine tests.
Some customer needs CSA certification for the transformer. CSA group can do CSA listed for transformer under 44kV, if the customer wants CSA group to inspect the transformer test and make the CSA listing for their transformer, Daelim will contact CSA group to confirm the cost and time, then add them into the quotation list. Customers can also do the CSA listing after they receive the transformer in their local.
Other customers may want a third-party inspection to their transformer, they will arrange third party companies such as SGS, BV, ANSI IBS to visit our factory and do the inspection work. Daelim also welcomes them to visit our factory.
Read on POWER SUBSTATION IN GUAYAQUIL
How to ship a high voltage power transformer?
Transportation- the transformer main tank, core, windings and any attached accessories shall be shipped filled with dry nitrogen gas from a suitably sized cylinder maintained at a positive pressure.
The moisture content of the Nitrogen gas shall not exceed 5ppm and a pressure monitoring gauge shall be installed. The above shall be the property of the client upon arrival to the site.
All other detached accessories that normally function under oil, shall be appropriately sealed to protect them against moisture or attack by weather.
All items shall be so packed as to protect them against weather and mechanical damage during the shipment.
The manufacturer shall supply and install disturbance / shock recorder to record any impact on the transformer during shipment. The shock absorber shall be installed at the factory and activated. The procedure for impact data retrieval shall be sent in soft, 2 weeks prior to shipment of the transformer. The impact recorder shall remain the property.
Thanks for sharing such a nice thought, article is fastidious, thats why i have
read it completely
This scam begins with a phone get in touch with informing you that you have won a cash prize,
a new automobile, or a getaway.
Feell free tto visit my page: 넷볼파워볼
There’s even a sepafate hair salon to have a tendency
to yohr highlighting and Keratin demands.
my blog post: 스웨디시 마사지
HKUST mixes soft and difficult capabilities inside its core courses and electives.
Here iis my web page … 다방알바
It’s also heavily invested in international stocks, which make up far more than two-thirds of its holdings.
my web site: https://jobs.ict-edu.uk/user/andymutch837500/
The initially point tto look for is a valid license from a reputable jurisdiction.
Here is my web-site click here
Playing games ranging from video poker to slots is a smooth practical experience.
my psge site
Your winnings are element of your taxable revenue, which determinees what marginal tax bracket you fall into.
Also visit my site – 코인파워볼
Quite a few of the casino’s guests rave about the casino complex ass a small business and
leisure location.
Also visit my webpaage – yrmkj.activoblog.com
The actions shows the demand of the industry and maake it far more
fair to every person.
Visit my blog – 파워볼
Laand 3 golden 7s and enjoy progressive jackpot winnings up to 200x.
Have a look at my web-site :: webpage
Sports bettors wageered $83.13 billion from January by means of the finih of November.
Here is my website – homepage
You will obtain an email from the NFL after your tickets
are prepared.
Feel free to vosit my blog post – 파워볼중계
But as stories have spread about the abuse thaat lots of migrant workers face
in these countries, South Korea iss becoming a preferred option.
Also visit my blog … 요정알바
Lavender and tea tree oil may perhaps also havce hormonal effects in some men and women.
Feel free to visit my blog – 스웨디시 홈케어
pathways and may perhaps promote a feeling of homeostasis in the nervous system.
Also visit my page 스웨디시마사지
Live dealer games are unavailable ffor clearing bonuses,
but all slots and table games are.
Here is my webpage: web site
The proper touch at the suitable tme can turn about even the worst of days.
Feel free to visit my wehsite :: 스웨디시 후기
Numerous disloke the chaebols for their disproportionate dominance oof the Korean economy, and of everyday life.
My blog post – 단기 알바
You can log into your account through yourr desktop or phone
andd transfer the tickets directly from your account.
My webpage; webpage
who can start virtually immedi…
Here is my site – 여성 알바
For dedicated crypto users, there’s also an added bonus of
up to $1,000.
Here is my blog; more info
Not all gambling bonuses and promotions are excellent for
all players.
Also visit myy site – 토토사이트
A great way of undertaking this is by providing bonuses,
VIP programs, and loyalty schemes.
my homepage; 토토사이트목록
Biycoin and Litecoin are only two of the quite a few cryptocurrencies accepted aat Everygame
Casino.
Here iis my website: 메이저카지노사이트
You can really feel secure delivering your details on suhh a comprehensive platform.
My website; 보증된카지노사이트
Superbook, Wynnbet, Unibet, BetRivers, Golden Nugget, Barstool, BallyBet, BetFred,Tough Rock, Desert Diamond, Betway,
SaharaBets, TwinSpires.
my blog – 메이저토토사이트
Thhe most surprising thing was that Ernst tied her Hardee’s encounter to modest income andd humble beginnings.
My web-site 요정알바
There are so quite a few casino games on offer you, from classsic table ames to
horse racing, poker, and live dealer games.
Here is my web page;here
Practitioners of old knew that heat applied to thhe body helped loosen up the muscles as
nicely as prepare the skin forr treatment.
my wweb blog; 타이 마사지
Get pleasure from a seamless mobile gaming expertise with the DraftKiings Casino App.
Here is my web page; http://www.canalfultonumc.com
If the collateral is worth significantly less than the outstanding debt,
the borrower can nevertheless be liable for the
remainder off the debt.
my page :: 자동차대출
Operating in Korea provided me wuth a wealth of experience
and a new perspective.
Look at my web blog; 미수다알바
Firstly, verify out Learner Support which iss funded by the
Government aand caan provide support for childcare, supplies and even accommodation.
Here is mmy web page; webpage
Continuing to function has a lot of positive aspects, but that doesn’t
imply it has to be in your current profession.
Feel free to visit my web blog; 텐카페알바
Thee terms and situations outline the guidelines and regulations that apply to the use of the casino and
any rights and responsibilities you have as a player.
Feel free to surf to my blog post … click here
You can make powerful connections wigh children and handle your own workload, so
it is a win-win.
Stop bby my web-site :: 단란주점 알바
The interest prices charghed by tribal lenders are usually larger than those charged by state-licensed lenders.
Have a look at my blog post :: 사업자대출
In October 2021, Gartner urveyed extra than 3,500 employees
around the world.
Here is my blog; 단기 알바
Crypto payouts are issued viia Bitcoin, and they take 2 days to attain your digital
wallet.
my web site – web site
“There were quite a few cultural variations… we had to get started all more than once again,” she says.
Also visit mmy homepage: 여성알바
We don’t travel with each other, we intersect each and every other’s orbit periodically.
Heree is my weeb site … 여성알바
Study truthful casino evaluations by people today who have attempted and tested
certain bonuses.
Feel free tto vksit my site: 카지노사이트
“Our economy continues to develop, which is great news foor all Albertans,” he stated.
Visit my webpage: 이지알바
Accomplish higher transparency annd security when eliminating the chances off fraud or any illegitimate activities.
My web blog :: 몬스터파워볼
You could possibly ear a recommendation to add a drop or
two of particular oils, like lavender, to youjr pillowcase.
Herre is my blkog post; 경남 스웨디시
Wagering on-line on sports in Massachusetts is as proteced as orderung UberEats.
Feel free to visit my homepage: deula.online
A soccial security quantity is a 13-digit quantity that alll residents, both national and foreign, are necessary to have.
Visit my homepage 텐카페알바
The example may give the impression that job sharers’ time on the job must be mutually exclusive.
Check out my homepage;web site
If the employer pays “straight pay” for that further 15 hours, they are violating the parameters of the FLSA, which,
however, is not an uncommon practice.
my wweb page :: 노래방 알바
At a tiume when the size of South Korea’s workforce is already declining and
the total fertility price has fallen to .84, women aare aan underutilized
resource for the economy.
Feeel free to surf to mmy web page :: 노래방 알바
I believe people who wrote this needs true loving because it’s a blessing.
So let me give back and show true love on change your life and if you want to seriously get to hear
I will share info about howto make money Don’t forget.. I am always
here for yall. Bless yall!
You can bet on Ligue 1 and other football competitions, the Prix dee l’Arc de
Triomphe, the Tour de France, and substantially a lot more.
Also visit my web-site :: click here
1 of ourr top picks on this list is a sportsbook that has
burst onto the sscene more than the past year or so.
Also visit my web site … 토토사이트목록
The advisory stated some of thee other jobs sought could be in fields
like mobile games, graphic animation, dating apps, and developing cryptocurrency platforms.
Visit my blog – web site
Foor the past few months we’ve received tons of inquiries from our Indian audience with
regards to functioning in Korea.
Also visit my web page: 쩜오알바
This signifies they would have to bet a total of
40,000 coins prior to a withdrawal can bbe made.
Also visit my webpage; click here
As for fiat, it will give you a 100% match on the next 8
payments uup to $500.
Here is my web blog: click here
Bovada seems too have rebounded in the minds off several a Reddit user as
well.
my homepage; get more info
A fixed-term employee can’t be engaged for much more than two years beyond
that, the employee’s status automatically switches tto complete-time status.
Feel free to visit my wweb page … 다방알바
The University of Hawaiʻi at Mānoa’s law college earned raanking among the nation’s top rated
programs, according to the U.S.
my blog post :: homepage
An impressive share! I’ve just forwarded this onto a co-worker who had been conducting
a little research on this. And he actually ordered me lunch because I discovered it for him…
lol. So allow me to reword this…. Thanks for
the meal!! But yeah, thanks for spending time to talk about this matter
here on your web page.