rapid pressure rise relay 1

[syawaluddin]

Hi All,

I would like to ask about the problem on the transformer.
There has been an alarm trip on the main transformer with an indication "alarm transformer rapid pressure rise relay trip".
if you can know it happened because what?

and where is the difference between rapid pressure rise relay with sudden pressure relay?

thanks all

 

[ScottyUK]

A sudden pressure relay responds to rapid pressure changes within the tank of a hermetic (non-conservator) transformer. It serves a broadly similar purpose to the surge element of a Buchholz relay on a conservator-type transformer, in terms of the faults it can detect.

Rapid pressure rises are usually a symptom of a fairly aggressive fault causing gases to form within the tank. If an SPR operates then you should exercise great caution and undertake thorough testing of the transformer and its oil prior to putting it back in service.

I don't believe there is any difference between a rapid pressure rise relay and a sudden pressure relay: different names for the same thing.

 

[dpc]

Agree with Scotty, but will add that these devices are quite sensitive and can misoperate if not properly installed, tested and maintained. But they are used because they are very good at detecting incipient faults and much more sensitive than other protection. So if it operated, you should assume there is an issue until you can verify that the transformer is OK. An oil test is recommended.

 

[syawaluddin]

thanks for scooty and dpc...
what makes me confused, when the trip alarm transformer that arises in DCS is rapid pressure rise relay, but actually there is oil coming out from relay bucholz. how do you respond to this?
if you can know the process of formation of gas in the main transformer is caused because what? is the penetration resistance penetrating? temperature? or other.

and what are the recommended test parameters for finding the cause of this problem?

Thank you for your attention and help.

 

[ScottyUK]

Oil coming out of the the Buchholz? That doesn't sound right. If oil is coming out the Buchholz then it is damaged.

What kind of transformer is this, a hermetic type, or a conservator type? The conservator is a large reservoir tank mounted a few feet above the transformer top plate and connected to the tank by a sloping pipe; the Buchholz is located mid-way along this pipe. An SPR typically looks like a square-ish lump mounted directly to the top cover of a hermetic transformer. I haven't seen one deployed on a conservator-type transformer before.

An oil lab can do dissolved gas analysis (DGA) and based on the ratios of the different gases present in the oil they can often make a fair guess as to what kind of fault you are dealing with - arcing, high temperature metal, low temperature metal, insulation degradation due to overloading, and so on. DGA works best when the oil is periodically sampled, allowing trends to be observed over a period of time, rather than as a snapshot after a fault, but it can still be useful post-event.

 

[stevenal]

SPR:

 

[ScottyUK]

Haven't seen that design before, this one is more common over here:

https://library.e.abb.com/public/7e...3cc/1ZUA5663-210_r2_Sudden Pressure Relay.pdf

 

[crshears]

An SPR typically looks like a square-ish lump mounted directly to the top cover of a hermetic transformer. I haven't seen one deployed on a conservator-type transformer before.

Hey Scotty, my utility uses both Buchholz and SPR relays on conservator type transformers, with the greater majority of them being of the latter configuration. My understanding is that since the oil due to its mass cannot accelerate quickly enough to dissipate a pressure wave, an SPR will readily detect an aggressive internal transformer fault.

Hope this helps.

CR

"As iron sharpens iron, so one person sharpens another." [Proverbs 27:17, NIV]

 

[ScottyUK]

Hi crshears,

That makes sense. Buchholz relays still predominate over here, backed up by a Qualitrol or bursting disc as the final protective layer. I have little faith in either of those last ditch protection layers, if there's a major fault then they aren't capable of relieving the pressure fast enough to prevent tank rupture. The faster response of the SPR over the Buchholz might make the difference given a sufficiently fast circuit breaker

 

[crshears]

My utility does still have oil circuit breakers in its portfolio, but where more severe duties are encountered the circuit breakers are of either the air blast breakers or sulfur hexafluoride interrupting type...plenty fast.

Carl

CR

"As iron sharpens iron, so one person sharpens another." [Proverbs 27:17, NIV]