# How to calculate load power demand in the 3 phase power system?

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#### Minh

Hi everyone!

I am studying the control strategies for SCESS (Super-capacitor energy storage system) which connects with a wind-diesel genset in a standalone system. I need your help with a technical problem. How can I calculate the amount of energy that the converter of the SCESS need to feed to the grid when the wind fluctuates or when the load suddenly changes?

Thank you very much!

#### PhilCorso

Regards, Phil Corso

M

#### Minh

Dear Mr. Phil Corso,

Thank for your suggestion! I am not sure what steady-state load flow called in my country. I have an idea to solve this problem as follow:
I can measure the instance phase currents and voltages, so I calculate the active power:

P = u_ac*i_a+u_bc*i_b

R = P/3/i_a^2 (assuming that we have 3 phases balance loads)

And I can calculate the load demand as:
P_demand = 3*U_nominal/R^2.

The different: delta(P) = P_demand - P is the power I need to compensate by SCEES.

Bests, Minh

#### PhilCorso

Minh… your approach seems enthusiastic but I question your Electrical Power Engineering knowledge! I suggest contacting companies like Siemens, ABB, and others, that provide SECC apparatus!

Contact me off-list if you want a technical critique of your solution!

Sincerely, Phil Corso [ [email protected] ]