Interference of radio communication by a new generator set

[PUNGLU]

Hallo guys,

A new gen set was installed to supply an isolated station. Apparently there is a radio installation for the police in the area and they are complaining of interference since the new gen set was installed.

How valid is the claim and how do I go about ascertaining whether the gen set is the actual cause of the inteference.

 

[waross]

What is the size of the generator? Does it supply the police radio?
Does it supply the whole area?
Is there a grid in the area?
Does the generator connect to the grid?
Static exciter?
Rotating excitor?
Comutator?
Slip rings?
Rotating field or stationary field?
I know some of the questions overlap, but you get the idea.
Tell us more about your installation so we can help.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[PUNGLU]

The generator capacity is 400 KVA.
A Tx steps up 415 to 11 kV for distribution, no grid in the area.
The field is rotating.

I have just been assigned the task and the details I got are scanty. I will be getting comprehensive details when I go to the area over the weekend.

 

[magoo2]

This might be a stretch but I remember a discussion about generator winding pitch and harmonics some years ago. The point is that some generators have a different harmonic spectrum than others and it might be worth checking. It would be good to have someone identify the interfering frequencies too.

Just a suggestion.

 

[dpc]

Well, can you test by shutting down the generator to see if the noise goes away? (Assuming the radio has another source of power).

A portable AM radio can give you a pretty good idea regarding noise being radiated by the generator or generator control systems. If the noise is being conducted on the power lines, it can be a bit harder to pin down.

 

[waross]

One approach is to check all connections for a poor connection. This is power as well as control. Try running the set with the generator breaker open, or the transformer disconnected from the generator. This will isolate the cause to either the generator or the downstream transformer and system.
Don't forget to check the connections on the Automatic Voltage regulator.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[wayne440]

The validity of the "interference" claim could vary widely depending on the technical competence of the reporting party. If the claim is based on tests by an experienced communications tech, you might want to investigate further. OTOH, if a passing policeman merely noted your crew working at the time their problem started, it could be only a non related, coincidental radio issue.

 

[PUNGLU]

I discovered that the earthing of the substation is poor and corrected it. I don't uderstand how this could cause so much interference but the problem seem to have eased.