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How to know if the Power supply is from Diesel Generator?

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s_p_chaudhary

New Member
Guys, I know nothing about electrical as I am Computer Guy but i do have a problem for you to apply your electrical mind... Let me try to explain. I live in a Flat in residential society, our society has 750 KVA big Diesel Generator and the power supply in my home comes 2 ways

1. Direct supply of Government Power Grid when electricity is there.
2. If electricity gone, the common society DG starts and we get power supply from DG.

the Meter to record the consumption for both is same and in my flat I have no way to know if the power that we are using is of DG or direct electricity...

I want to know the possible ways of implementing any mechanism, indicators etc in my Flat so if the DG supply is on, the indicator can light on and if DG is off and supply is from Government Power Grid.... light is of so I can see if DG is ON and can consume the DG units accordingly as DG supply units costs 3 times the normal government Grid supply.

Any idea of having any such mechanism in my House to differentiate between both kind of supply. ?
 

ke5frf

New Member
Unless there is some characteristic noise or variability in one supply versus the other, IT SEEMS TO ME it would be rather difficult to differentiate the two. It is certainly possible that one source has a slightly higher peak to peak voltage than another...i.e. one may read 118 VAC with a voltmeter and the other may read 115 VAC (I'm using American standard for the example)

The next step would be to get a datalogger or chart recorder designed and scaled to read MAINS voltage. A computer with an A/D interface and software can do the same thing, or better yet, many modern digital multimeters come with software and a USB port for data logging!

Here's a voltage chart recorder if you want a paper record:
Rustrak AC Voltage Strip Chart Recorders

Here is an inexpensive digital multimeter that computer interfaces for datalogging:
Digital Multimeter with PC Interface

And many more expensive, brand name multimeters have datalogging and trend capture built into them.

So, if you could identify a time when, with certainty, you can identify the power generator, and if you can contrast the two power sources by a slight voltage difference or perhaps even a slight frequency offset (i.e. your mains might be 50 Hz, and if you analyze the two sources, one might be exactly 49.65 Hz while the other is 50.35, and assuming your meter or software has that kind of resolution)

You might notice one supply source is very stable while the other has a slight drift.
etc etc.

Once the pattern is determined, it would be an easy matter to identify bump transfers where the power drops momentarily when switching from one power source to the other. These would be your datalogger "markers", and from there the time duration under each source could be measured.
 

MikeMl

Well-Known Member
Most Helpful Member
Just sense when the DG is running.

Can you get access to the DG? If so, is there an AC outlet on the DG that is live only when the DG is running. If so, plug a surplus wall-socket charger into the outlet, and extend the isolated DC output wiring from the charger to your apartment. The DC will be present only when the genset is running. You can use it to light a LED, or something...
 

JimB

Super Moderator
Most Helpful Member
our society has 750 KVA big Diesel Generator and the power supply in my home comes 2 ways

1. Direct supply of Government Power Grid when electricity is there.
2. If electricity gone, the common society DG starts and we get power supply from DG.

the Meter to record the consumption for both is same and in my flat I have no way to know if the power that we are using is of DG or direct electricity...

DG supply units costs 3 times the normal government Grid supply.

Am I missing something here?

There are two supplies, Mains and Generator
Your flat has ONE meter
Generator electricity is three times the cost of mains electricity

So, when you pay your electric bill, how does the person issuing the bill differentiate between Mains and Generator so that you are charged correctly?

I just dont see how you knowing when you are on Mains or Generator will help the situation.

JimB
 

gabeNC

Member
I would imagine that he would want to conserve more when paying the DG rate, plus be able to check that the bill is correct.

If he begins to log it, I could see there being alot of false positives from transients or brown out type conditions. He fires up the microwave, neighbor's dog pisses on the meter.. etc.
 

crutschow

Well-Known Member
Most Helpful Member
You might be able to detect a slight change in the power frequency when the DG is running.
 

Mark_R

Member
As someone asked, do you have access to the generator?

How far from your residence? There are all kinds of radio transmitter / receiver contact closure extenders that you could use. The community could install 1 transmitter at the generator and everyone could have a receiver. We've used these and they work good ==> Product Information Page - Linear LLC

Contact closure in ===> contact closure out a few miles away.

Maker claims 10 miles line of site, but that may be optimistic. $225-ish each for the transmitter and receiver.

If it's a quality generator, There should be no reliable signature on the power line to detect that it's running. Your best chance would be the frequency being a bit off. In the US at least, the grid is unlikely to be off frequency by more than a few hundredths of a HZ. Some generators cant hold that tolerance. I would think it would be pretty hit or miss.
 
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mneary

New Member
Look across the street at a house that doesn't have backup power. If their lights are out then you are probably on DG.
 

pkshima

Member
see if it smells like diesel :D

I guess DGs make a nice roar when they start up and is clearly audible at good distances. So you may detect that ?

Also in some societies, some devices like fridge/ac fail to run on DG so you may detect that alternately.
 

HiTech

Well-Known Member
Since you are a computer guy, connect your PC to a quality UPS unit that can be monitored by the PC and dedicated software from the UPS mfgr. It will keep a detailed log of electrical events as they occur.... like when the mains are switched over to the DG and back.
 

tcmtech

Banned
Most Helpful Member
Given its a 750 KW DG unit I assume your a rather small community and not too far form the generator itself? Around here that size of generator would only be good for a town of less than 400 people or around 200 homes. Less with any businesses in the supplied area.

My personal experience has shown my old military gen set I use for backup power has a more rounded and correct looking sine wave than the line sources do. But it does also have a slight tick on the leading edges of each half of the sine wave for some reason.
With a good oscilloscope you may be able to determine what source is being used by waveform shape or anomalies alone. :)

So how does the utility company break down your meter readings to relate how much power was being used while you where on one power source or the other?
Do you have remote read meter systems where you are?
If so they probably take a meter reading just before they switch over and then one just before they switch back. Using the two readings and a time stamp for each reading its easy for the utility company to record your usage during both supply times and bill you accordingly.
 

Warpspeed

Member
You might be able to detect a slight change in the power frequency when the DG is running.
This is the important clue.

ANY generator will change frequency slightly as the load changes.
The grid is absolutely huge, so the frequency will be very very stable.

A diesel, even a big one, will still fight to maintain the correct frequency. So as the load changes, the frequency will wobble slightly, and you will be able to measure that with suitable equipment.
 

MikeMl

Well-Known Member
Most Helpful Member
This is the important clue.

ANY generator will change frequency slightly as the load changes.
The grid is absolutely huge, so the frequency will be very very stable.

A diesel, even a big one, will still fight to maintain the correct frequency. So as the load changes, the frequency will wobble slightly, and you will be able to measure that with suitable equipment.

So do a simple test. Get a small transformer (not a switch mode one) AC output wall-wart left-over charger from a defunct battery-powered appliance. Say is has a 10VAC output. Make a two resistor attenuator (or use a pot) to reduce the voltage to < 1V. Hook it to the line input of your computer sound card. Get one of the many free programs off the web which will do Spectral Analysis. Try displaying the spectrum while running on city power and compare that to what it looks like while running on the Genny. If there is a substantial difference, then you can write a computer application to tell you which source of power you are running on....
 

Warpspeed

Member
A phase locked loop with a very long time constant would do it too.

It would lock onto the long term average mains frequency, and the phase detector would output very narrow pulses for each cycle by cycle slight phase change.
 

Ashutosh Kumar

New Member
Guys, I know nothing about electrical as I am Computer Guy but i do have a problem for you to apply your electrical mind... Let me try to explain. I live in a Flat in residential society, our society has 750 KVA big Diesel Generator and the power supply in my home comes 2 ways

1. Direct supply of Government Power Grid when electricity is there.
2. If electricity gone, the common society DG starts and we get power supply from DG.

the Meter to record the consumption for both is same and in my flat I have no way to know if the power that we are using is of DG or direct electricity...

I want to know the possible ways of implementing any mechanism, indicators etc in my Flat so if the DG supply is on, the indicator can light on and if DG is off and supply is from Government Power Grid.... light is of so I can see if DG is ON and can consume the DG units accordingly as DG supply units costs 3 times the normal government Grid supply.

Any idea of having any such mechanism in my House to differentiate between both kind of supply. ?

Dear,

We have developed a small device that solves the problem you are looking for. It is a Plug-In device & can be plugged in any 3-Pin socket in your home. If you are still facing the problem then we can move ahead.

Ashutosh Kumar
 

dr pepper

Well-Known Member
Most Helpful Member
Thats a 5 year old thread, I dont think the o/p wll be listening.
 

Sanjay Dhingra

New Member
Dear,

We have developed a small device that solves the problem you are looking for. It is a Plug-In device & can be plugged in any 3-Pin socket in your home. If you are still facing the problem then we can move ahead.

Ashutosh Kumar

We also have a similar requirement, Please mail the datasheet & price of the device to
address deleted - moderator


Sanjay Dhingra
 
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large_ghostman

Well-Known Member
Most Helpful Member
Leave a window open you will hear it ;)
 
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