Induction Generators

[SCIM]

Dear all,

 

I have a couple of questions on MV Induction Generator performance and operations

 

1. When the induction generator is introduced into the grid, will this result in a drop in PF of the generator due to the reactive excitation current drawn from the grid?

I think it should but how long will this last for?

 

2. Will varying of the loading (i.e Variance in P.F) from the GRID affect the PF of the generator?

 

3. Will Power Factor Correction (Without Switching) affect the Power Factor of the generator?

Also, must the capacitor banks be switched off after start up or is it meant to be kept ON at all times?

 

4. What will be the most common problem if the recorded PF of the generator from site differs from tested results?

 

5. Is there a vast difference in Power Factor if an induction generator is mechanically driven (i.e generating) and when tested base on loading Electrically? Should be the Same???

 

6. Any good books or papers to recommend on for 3 Phase Induction Generator usage or troubleshooting guide?

 

Currently, our issue is that the Power Factor reading of generator on Site differs by about 8-9% compared to testing done in the factory. There is no problem in the efficiency figures. Only problem is with the PF figures.

The loading and equipments both on site and factory has been checked and driven loading is correct.

 

Generator was tested to JEC standards with result figures base on circle diagram.

 

Has anyone encountered something similar?

 

Cheers

SCIM

 

[mariomaggi]

SCIM,

our issue is that the Power Factor reading of generator on Site differs by about 8-9% compared to testing done in the factory.

do you checked the harmonic content in your plant? The difference in values obtained should be a reading error due to harmonics.

 

Regards

Mario

 

I have a couple of questions

1.

2.

3.

4.

5.

6.

 

[SCIM]

Hi Mario,

 

I am not too sure as to how much harmonics content would be within the system and am checking.

Can you please explain more as to how the harmonics content would led to error reading? I am quite still puzzled...

 

SCIM

[SCIM]

Hi All,

 

Would like to add further information, the harmonics within the system is less than 1.5% and this generator was test in accordance to JEC2137 for Induction Generators.

 

So far, could only conclude that either the setup of the overall system has an error somewhere that is causing the error in PF reading or another very unlikily caused is that the method of test to JEC2137 with Circle diagram calculation for induction machine is too generous (by about additional 3-5%) as compared to the actual P.F figures. Stating it's quite unlikily as the design data was pretty similar (slightly Higher) to the tested figures.

 

Anyone encountered similar events with JEC2137 Standards??

 

Cheers

SCIM