Hello !

i want to measure voltage and current about a DC - overheadline in two different substations. The DC voltage is about 700V and the current about 1000A.
My idea is to measure the current above a shunt resistance. The shunt resistance has a Current /Volt ratio of 1000 A = 40 mV.
I have to record this data and sync it.
So my question is if you hade some ideas which device i can use. It should have the property to DataLog (round about 18 000 logs). Maybe its possible for measure with two channels. (both DC V!)

And i have no clue how to sync this logs except later manuel at the PC.

greetings

 

You looking for a turn key solution or design this (circuit design, software coding)
from ground up ?

Regards, Dana.

 

You looking for a turn key solution or design this (circuit design, software coding)
from ground up ?

Regards, Dana.

A discussion about the idea i have or maybe someone has an other better idea to do that

 

Some questions :

1 - Distance of sensor from approximate location of data logger ?
2 - Accuracy and resolution of measurement ?
3 - I assume isolation of data Logger from host paramount ?
4 - Any preference data logger wireless, wired, or plastic fiber optical link to host ?
5 - Power source for data logger available, batteries, low DC V, AC..... ?
6 - Shunt in high side of line or is one side at ground ?

Regards, Dana.

 

With only what you posted I can tell you how I would go about it and again, only based on what you posted and I will assume an industrial application as I don't see many home projects involving 700 VDC and 1,000 Amps DC.

I would use a 1,000 AMP DC Current Shunt, I would prefer a good DC Current Transducer but getting a 1,000 amp version is difficult, 700 Amp easy but 1,000 amp not too common so I run with a low side shunt. I would use a commercial meter to measure the shunt which can be scaled, while the Omega DP 41E with an analog out card is not cheap it will do fine. You can likely find a much lower cost, scalable meter with an analog out. The idea being you want a scaled analog out voltage which will be proportional to the measured current. The DC voltage I would do the same and find a 0 to 1,000 VDC meter with ascalable analog out and you may need to use a voltage divider front end for the meter. That involves high voltage resistors for the divider. Again scale the analog out of the meter. The DP41 I mentioned earlier has a 100 volt bi poler range so voltage divide the 1 KV down 10:1 and and again use the scaled analog out to drive your data acquisition.system. All a matter of exactly what you want to do, how accurately you need to do it and a budget,

0 to 1,000 ADC = 0 to 10 VDC
0 to 1000 VDC = 0 to 10 VDC

I would take my scaled analog outputs and run them into a simple A/D converter capable of displaying the two signals and plotting them. This is also where you need to decide the uncertainty and resolution you can live with.Just get a simple USB Analog to Digital with storage capability, even something like a Dataq simple starter kit. The included basic software allows you to plot and store. There are other ways to go about it depending on accuracy requirements and of course budget,

Ron

Ron

 

Hey Dana! Hey Ron!
thank you for your interest!

Its for a project in my study. its connected with a Trolleybus overheadline network.
We will disconnect part of the line from the network to perform measurements of the power of the two substations which feed in the section.

Some questions :

1 - Distance of sensor from approximate location of data logger ?
2 - Accuracy and resolution of measurement ?
3 - I assume isolation of data Logger from host paramount ?
4 - Any preference data logger wireless, wired, or plastic fiber optical link to host ?
5 - Power source for data logger available, batteries, low DC V, AC..... ?
6 - Shunt in high side of line or is one side at ground ?

Regards, Dana.

1- I dont know what you exactly mean. I want to connect the DataLog direct with the divice. To the measurement points i will use cable. but to answer your question.. its like max.4 meters.
2. At one point the Current can increas with 40A/s ... that would be 1,6mV about the Shunt.. my idea was to find a device with an Accuracy about 400mV +/- 0,01%
3.,4 no specific requirement.
5. Yes it is a normal 230V AC
6. I actually not sure about that, but i think it high side

With only what you posted I can tell you how I would go about it and again, only based on what you posted and I will assume an industrial application as I don't see many home projects involving 700 VDC and 1,000 Amps DC.

I would use a 1,000 AMP DC Current Shunt, I would prefer a good DC Current Transducer but getting a 1,000 amp version is difficult, 700 Amp easy but 1,000 amp not too common so I run with a low side shunt. I would use a commercial meter to measure the shunt which can be scaled, while the Omega DP 41E with an analog out card is not cheap it will do fine. You can likely find a much lower cost, scalable meter with an analog out. The idea being you want a scaled analog out voltage which will be proportional to the measured current. The DC voltage I would do the same and find a 0 to 1,000 VDC meter with ascalable analog out and you may need to use a voltage divider front end for the meter. That involves high voltage resistors for the divider. Again scale the analog out of the meter. The DP41 I mentioned earlier has a 100 volt bi poler range so voltage divide the 1 KV down 10:1 and and again use the scaled analog out to drive your data acquisition.system. All a matter of exactly what you want to do, how accurately you need to do it and a budget,

0 to 1,000 ADC = 0 to 10 VDC
0 to 1000 VDC = 0 to 10 VDC

I would take my scaled analog outputs and run them into a simple A/D converter capable of displaying the two signals and plotting them. This is also where you need to decide the uncertainty and resolution you can live with.Just get a simple USB Analog to Digital with storage capability, even something like a Dataq simple starter kit. The included basic software allows you to plot and store. There are other ways to go about it depending on accuracy requirements and of course budget,

Ron

Ron

thank you for this idea. To work with a voltage divider was also my thoughts. The budget is about 500€.
I will inform myself about it, and come back again.

Greetings

 

Pretty cool subject and reminded me of growing up with overhead electric trolley cars in NYC.

Ron