Need help on how to come up for settings for GE750
Need help on how to come up for settings for GE750
(OP)
Hello Everyone,
I am working on a project which has several GE relays (GE 750 multilins). I am reading through its instruction manual on how to provide the settings for : 32R- Reverse Power, Over Voltage and undervoltage elements.
The confusion I am having for these elements is:
1. Reverse Power - The pick-up here is determined by Settings x Rated power. The manual define rated power as Rated Power = sqrt(3) x Vsec (line - line) x VT ratio x Isec (rated) x CT ratio. Now the question how is the rated power calculated I am assuming the Vsec and Isec is the PT sec and CT sec respectively. Am I correct?
2. Voltage and Undervoltage - It is determined by Settings x VT. Is the VT here the secondary voltage of VT's.
It will be really helpful if someone can help me with an example.
Also is there a good way to learn more on how the settings and how to program these common relays used in the industry ? Like a document with example similar to Basler instruction manuals.
I am working on a project which has several GE relays (GE 750 multilins). I am reading through its instruction manual on how to provide the settings for : 32R- Reverse Power, Over Voltage and undervoltage elements.
The confusion I am having for these elements is:
1. Reverse Power - The pick-up here is determined by Settings x Rated power. The manual define rated power as Rated Power = sqrt(3) x Vsec (line - line) x VT ratio x Isec (rated) x CT ratio. Now the question how is the rated power calculated I am assuming the Vsec and Isec is the PT sec and CT sec respectively. Am I correct?
2. Voltage and Undervoltage - It is determined by Settings x VT. Is the VT here the secondary voltage of VT's.
It will be really helpful if someone can help me with an example.
Also is there a good way to learn more on how the settings and how to program these common relays used in the industry ? Like a document with example similar to Basler instruction manuals.






RE: Need help on how to come up for settings for GE750
VT x CT x PTR x CTR x root 3 x cos theta.
remember that CT and VT are variables set in the System Sensing page.
Undervoltage is per unit of VT, so just becomes a number. Just have to check if the 27 element operates in a phase-to-phase or phase-to-ground basis.
RE: Need help on how to come up for settings for GE750
I learned this the hard way.
old field guy