Enass,

Check out the classic book:

A. J. Wood, and B. F. Wollenberg, "Power Gerneration, Operation, and Control", WIley.

-Sanjay

There are many methods to account the constraints violations in solving economic dispatch problems and similar ones. The best one based on my work is the Self-Adaptive Penalty functions. In such methods, no need for assuming weight factors or parameters during optimization process. 

Dear Enass Mohammed

Considering penalty factor is a modelling issue of optimization problem. It can be applied in solving any type of optimization problem if there is some constraint violations. 

You may find how objection function is penalized in the following two articles shared on RG.

https://www.researchgate.net/publication/297245624_Particle_Swarm_Optimization_Algorithm_and_its_Codes_in_MATLAB?ev=prf_pub

https://www.researchgate.net/publication/296636431_Codes_in_MATLAB_for_Particle_Swarm_Optimization?ev=prf_pub

Research Particle Swarm Optimization: Algorithm and its Codes in MATLAB

Code Codes in MATLAB for Particle Swarm Optimization

Dear Enass Mohammed

Penalty function is used to consider any violation of the dependent variables as increase in the objective function.

Thus, using any metaheuristic algorithm, you can follow the steps-:

------------1. initialize the (individuals) control variables (active power generation)

2. run the load flow and check the limits of the dependent variables

3. if there is a violation, evaluate the corresponding penalty terms

4. Evaluate the objective function incorporating the penalty terms

5. Update the individuals and repeat steps 2-4 until stopping condition