OLTC - On Load Tap Changer
OLTC - On Load Tap Changer
(OP)
Dear all,
I would like to seek opinion how you guys review the submission approval for transformer accessories transformer - OLTC.
As far as I know, substation here, they prefered MR Germany - OLTC.
I would like to seek opinion how you guys review the submission approval for transformer accessories transformer - OLTC.
As far as I know, substation here, they prefered MR Germany - OLTC.






RE: OLTC - On Load Tap Changer
-Rated voltage, rated current and rated step voltage match with the maximum values of transformer during in service or testing at factory
- Guaranteed number of operations before overhaul
- Type test report in line with relevant IEC
- Minimum protection provided - bursting plate, surge relay, out of step relay
RE: OLTC - On Load Tap Changer
RE: OLTC - On Load Tap Changer
I would like to seek clarification on regards your suggested few points;
i) Guaranteed number of operations before overhaul, overhaul means maintenance as I suppose ?
ii) Bursting plate,surge relay, out of step relay, what is that ? kind new terms for me.
ScottyUK,
Your utilities prefer Reinhausen yeah.
Diverter switches is referring the tap-changer switcher right ?
RE: OLTC - On Load Tap Changer
You should look at the maintainability of the design: top-mounted tapchangers are common but you will need to provide a lifting frame or gantry to remove it for maintenance. A high voltage OLTC is a substantial size but is also a fairly delicate piece of precision engineering - removing it and replacing it in the tank is not a trivial task.
Make sure that you determine whether the OLTC manufacturer, or perhaps the transformer OEM, have suitably trained and experienced personnel available in your location. You might consider integrating a long-term service agreement with the manufacturer as part of the bidding process.
RE: OLTC - On Load Tap Changer
Number of operations meant arcing contact life after which contacts to be changed.Bursting plate=pressure relief device fitted to arcing chamber, surge relay= relay mounted between the diverter chamber and its oil conservator to detect excess surges from faulty diverter switch.
RE: OLTC - On Load Tap Changer
You mention lifting frame / gantry, do you mean provide on the transformer or OLTC itself ?
Well, honestly, I havent see any high voltage power transformers myself.
Do you agree what prc stated in his reply on "Once upon a time almost all leading transformer manufacturers were making OLTC.Then the mergers started due to economies of scale.In 1960's and 70's UK had atleast 4-5 well known tap changer makers, but today none.(Scotty can correct me)Today there are two popular designs available around the world -MR and ABB,both reputed and reliable.There are many smaller manufacturers in China &India with limited markets." ?
prc,
Minimum protection means the OLTC design specifications suppose to have these kind protection for itself.
RE: OLTC - On Load Tap Changer
prc knows the transformer industry rather well.
Reinhausen and ABB are both well-respected manufacturers and are often specified by name in client specifications. The old British manufacturers like Ferranti, English Electric / AEI / GEC, Fullers, Hawker-Siddeley and ATL are all gone. I think Brush are still in the business or were until recently: I have an idea that Brush merged with the old ATL company and Hawker-Siddeley under FKI's ownership but I might be wrong about that.
RE: OLTC - On Load Tap Changer
RE: OLTC - On Load Tap Changer
Appreciate for your sharing input.
prc,
I'm wating for prc reply on regard minimum protection. Does it give minimum protection for power transformer or for OLTC itself ?
RE: OLTC - On Load Tap Changer
OLTC will have its own surge relay and pressure relief device. Transformer will have a separate pressure relief device. So the protection will be two separate and independent entities.
RE: OLTC - On Load Tap Changer
RE: OLTC - On Load Tap Changer
RE: OLTC - On Load Tap Changer
RE: OLTC - On Load Tap Changer
In the operating manual for the Reinhausen Vacutap VR OLTC, the instructions have a warning at the beginning of the manual that states "Connect the protective relay in such a way to ensure that the transformer is immediately disconnected when the protective relay is tripped." The standard RS 2001 surge relay includes just a single tripping contact, with multi contact versions available upon request. The relay resets once the flow stops, so either a seal-in relay or an alarm contact is needed to identify which phase trips.