Line Phase Comparison Relay vs Line Differntial Relay 6

[slavag]

Dear All.
What are advantages and disadvanteges of both type of protective relays.
Best Regards.
Slva

 

[NCTHAI]

Diff relays - needs longer control cables or some other circutary for current coparision purpose but are very highly accurate and reliable.

Distance Relays - Economical but not as accurate as differential relays. With new technology numerical relays algorithms, they are faily reliable.

NC

 

[slavag]

NCTHAI.
Thanks a lot for your reply.
Distance vs Differintial is not new for me.
My problem is some new type of protective relay ( for me, of course) line phase comparison relay.
According to manuals it's more or less diff protection, but base on another prinicpal, operated via PLC. ( power line carrier).
Something like to L60 vs L90 of GE, or some same types of ABB or Areva.
What is this, what is advantages, what is expirience.
Best Regards.
Slava

 

[slavag]

Guys!!!! Someone!!!
line phase comparison relay
What is this? It's work?

 

[dpc]

http://selinc.biz/techpprs/6140.pdf

http://www.selinc.com/sel-311l.htm

Slava,

Maybe this will help. I think they are basically differential relays using a comm channel to provide current data to the relay on the other end of the line. I know that Bonneville Power has used some RFL units, but I never got too involved with any applications.

 

[stevenal]

The REL352 is a phase comparison type of differential relay. The operating quantity is supposed to be more tuned to the current phase angles that to magnitudes. Settings look rather complicated compared to straight summation.

http://www.abb.com/product/db0003db004281/c12573e70033041985256aa100637bba.aspx

 

[slavag]

Dear NCTHAI, Dave and Stevenal.
Thanks a lot for your reply.
As I understood, isn't standard application in utilities.
Best Regards.
Slava

 

[lz5pl]

slavaq, according to me stevenal's explanation although very short is most correct. As per my knowledge phase comparison principle is used when communication channel with less bandwidth is available. Hence it has been used before, but now with relatively cheap OPGW's it is not a problem to ensure enough data speed to exchange full numerical information and line differential protections are more used nowadays.

------------------------
It may be like this in theory and practice, but in real life it is completely different.
The favourite sentence of my army sergeant

 

[NAZ55]

Phase Comparison - Line Diff comparisons

 

[NAZ55]

Phase Comparison Scheme from Areva T&D

 

[slavag]

Good Morning.
Lz5pl and Zazmat thanks a lot to you too.
Lz5pl, I agree with you, you know what is DFZ and I try understand for what new type of relays with this algorthm.
Zazmat... no word.
Best Regards.
Slava