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Pole slip protection/ calculations
- Thread starter Flashover
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I'm sorry but I don't know any website describing this protection. Some information can be found in the protection manuals of several manufacturer. For example, see the manual of the ABB REG316.
The setting of the 78 is not simple because it protects the generator against loss of steps caused by electromechanical transients that could occur in a grid.
So a transient stability study only can give you the necessary information for the 78 setting. But usually the data of the grid are unknown.
I could describe you my thumb rule:
1- suppose that you are measuring the system impedance at the generator terminals.
2- the segment AB of the system is composed by the gen impedance AC, the step-up transformer impedance CD and the Grid (equivalent) impedance DB. AB = AC+CD+DB
3- the AC segment is in the third quadrant of the (R,X) space and its length is the transient impedance of the gen.
4- The CD segment is in the 1st quadrant and its length is the transf impedance
5- the DB segment is in the 1st quadrant and could be about 3 times CD (DB=3*CD)
now you have the representation of your system in the impedance loci.
You have to define the characteristic of the protection (lenticular, bouble bindings...) But this setting of the protection depends on the protection itself, because each manufacturer propose a different algorythm (see the differences between the GE LPSO and the ABB REG316, I prefer the last one).
Sorry, I cannot help you anymore without further information.
Alex68
The setting of the 78 is not simple because it protects the generator against loss of steps caused by electromechanical transients that could occur in a grid.
So a transient stability study only can give you the necessary information for the 78 setting. But usually the data of the grid are unknown.
I could describe you my thumb rule:
1- suppose that you are measuring the system impedance at the generator terminals.
2- the segment AB of the system is composed by the gen impedance AC, the step-up transformer impedance CD and the Grid (equivalent) impedance DB. AB = AC+CD+DB
3- the AC segment is in the third quadrant of the (R,X) space and its length is the transient impedance of the gen.
4- The CD segment is in the 1st quadrant and its length is the transf impedance
5- the DB segment is in the 1st quadrant and could be about 3 times CD (DB=3*CD)
now you have the representation of your system in the impedance loci.
You have to define the characteristic of the protection (lenticular, bouble bindings...) But this setting of the protection depends on the protection itself, because each manufacturer propose a different algorythm (see the differences between the GE LPSO and the ABB REG316, I prefer the last one).
Sorry, I cannot help you anymore without further information.
Alex68
There are some applications notes in the manual for the Areva Micom P343.
This might be available on the website.
Also try the NPAG page of the same website - it has a generator protection section with information on pole slip protection too.
This might be available on the website.
Also try the NPAG page of the same website - it has a generator protection section with information on pole slip protection too.
Download GER-3179 and GER-3180 from the publications section of the General Electric web site:
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