I am trying to simulate a three phase system in which power is to be transferred to the grid from photovoltaic system and no three phase load is connected at PCC.I wish to maintain the reactive power transfer to zero and maintain system at unity power factor.
(Most of the research papers I have seen have load connected in between)
Let me know of any control algorithm which I can use to achieve this.
You can see this study:
I hope that it would be useful for you.
Hi Maulik, I am not sure what you mean by 'no load connected in between'. In between what? The phases of the load? You can't transfer power to a non-existent load. You don't want a load connected between the PV array and the grid, that just wastes power. Assuming your grid is large and handles much more power than the PV array, all you require is a peak power point tracker to operate the PV array at its optimum, and an efficient inverter (3 phase) to drive the grid. The inverter just drives as much current as is available into what it sees as a constant (RMS) voltage load of very low input impedance. I don't see the problem here.
@Tony
I mean no load is connected in parallel at point of common coupling. I wish to know for following configuration:
PV(MPPT)-Inverter-Grid
I wish to synchronize output of inverter with the Grid and want to have zero reactive power transfer to grid and for doing that I would have to employ a control algorithm
Hi Maulik, You must read up literature on the design and operation of grid connected inverters before building anything and connecting it to the grid. if there is a fault, design or random failure, you can destroy your equipment (and yourself) very easily. With that warning I don't think the algorithm you require is very difficult. The mains represents a sine wave voltage source with extremely low impedance, so your algorithm simply has to maximise the RMS current transfer into the grid. If your circuit drives current exactly proportional to the instantaneous grid voltage, by definition you will be working with zero power factor. You will be helped considerably if you have 3 phase connection as all phase currents sum to exactly zero at all times.
You may wish to fit islanding protection (automatic disconnect if the grid supply fails). This done by measuring either or both the voltage and grid frequency and if either go out of expected range, you shut down, fast.
Please read the literature on mains connected invertors, and safety precautions to take before proceeding!
Best wishes!
First of all you have to calculate power factor at PCC and after that calculate the reactive power consumed by your capacitor filter. So you know that what amount of power grid needs to maintain unity power factor. Based on current control scheme you can inject active or reactive power at PCC and maintain power factor to unity .
Please refer following paper:
SMART INTERCONNECTION OF A PV/WIND DG MICRO GRID WITH THE UTILITY DISTRIBUTION NETWORK by K.M.Abo-Al-Ez X.Xia and J.Zhang
Hi Maulik Kandpal ..first thing in PV generation...is the source of generation capable of generating reactive power? so which reactive power control you are looking at PCC.
Second thing the power flow is totally controlled by loads on the system..but you are trying to have no load at PCC.. In grid the reactive power control is only possible by controlling voltage at PCC..since reactive power flow totally depends any Voltage profile and active power depends on frequency of the system...
Hope this may help you..best of luck
Hi Maulik, power factor is a characteristic of an electrical circuit containing some sort of load with current driven from a generator. It is the cosine of the phase angle between the voltage and current measured usually at the terminals of the circuit. It is determined by the vector sum of resistances and reactances around that circuit, which would have to include the generator if its resistance or reactance were not negligible.
So do you want your PCC to modify the power factor of an existing circuit or circuits in the grid? You may find the impedances there are very small and any changes will require the generation of very large reactive currents.
Now, PCCs supply real power, not reactive power. Do you want your PCC to be a power factor corrector? That is a different device altogether. Just focus on making the current injected into the grid in phase with the instantaneous grid voltage as measured at the point of injection, and you will be doing fine. Don't worry about "reactive power" (there's no such thing actually, reactances don't dissipate or generate power).
Best wishes
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