How to induce frequency change through load change in grid connected PV system model in MATLAB Simulink

In 250kW PV system connected to grid model in matlab, i want to induce a frequency change through load change. In this model 3 phase source model is represented as grid and when load change is induced it shows no deviation. Is there any way or example model available to simulate the grid and limit its generation, so that the load change can introduce the frequency deviation.

Answer 1

[Riya]

Hello Vishnu,

As per my understanding, you want to know How to induce frequency change through load change in grid connected PV system model in MATLAB Simulink.

Please note that in a real-world power system, the frequency is affected by the balance between power generation and power consumption. If there is an imbalance, the system frequency will deviate from its nominal value. However, in a typical grid-connected PV system model in MATLAB Simulink, the grid is often represented as an infinite bus, meaning that it has an unlimited power capacity, and the frequency remains constant regardless of the power flow to or from the grid.

To simulate frequency changes in response to load changes, you need to model the grid with a finite capacity and implement the dynamics of a synchronous generator, which can exhibit frequency deviations when there is an imbalance between generation and load.

Here is a high-level overview of the steps you could take to create a model in MATLAB Simulink that allows for frequency changes due to load variations:

• Replace the infinite bus with a synchronous generator model.
• Add a governor system to control the engine speed (and hence frequency) and an AVR to manage the generator's terminal voltage.
• Integrate a Load Model
• Add a PV Array Model: Your 250 kW PV system model should be connected to the grid through an inverter. Ensure the inverter control system can respond to grid frequency changes (e.g., through frequency-watt control).
• Simulation and Analysis: Run simulations with varying load scenarios and analyse the frequency response of the system. You can use scopes or MATLAB's workspace to record the frequency and other relevant data.

For more information you can refer following articles for more information about the example model mentioned:

• https://www.mathworks.com/help/sps/ug/detailed-model-of-a-100-kw-grid-connected-pv-array.html
• https://www.mathworks.com/matlabcentral/answers/524958-single-phase-grid-connected-pv-systems?s_tid=answers_rc1-1_p1_BOTH

I hope it helps!