We got a question from AK TIWARI. He is asking:
1) What will be the recorded demand if a constant load of 1 kw is applied through a 30 minute demand meter ?
2) What will be the recorded demand if a constant load of 1 kw is applied through a 15 minute demand meter ?
Demand measurement is an additional function for energy meters. It’s helpful for utilities to bring down the peak load in the grid.
The demand register (formerly also called maximum demand) shows the maximum power over a time interval. This is typically 15 minutes.
To your question:
We have a constant load of 1 kW. The meter is recording the energy in an evaluation register for 30 minutes. So, this register has after 30 minutes a energy of 0.5 kWh.
After 30 minutes the registered energy is divided by 30 minutes to get the power and the evaluation register is reset.
You see that the factor time is eliminating itself. The demand register will show 1 kW.
For #2 it’s the same. The demand register shows 1 kW after 15 minutes.
In our maximum demand post you can find a simulation with a 24 hour load profile to study the impact on sliding or fixed integration periods.
Editor's note: This article was originally published in October 2019 and has been updated for comprehensiveness.