hello sir

This mmf or magneto motive force in the secondary winding produces flux φ2. This φ2 will oppose the main magnetizing flux and momentarily weakens the main flux and tries to reduce primary self induced emf E1. If E1 falls down below the primary source voltage V1, there will be an extra current flowing from source to primary winding. This extra primary current I2′ produces extra flux φ′ in the core which will neutralize the secondary counter flux φ2. Hence the main magnetizing flux of core, Φ remains unchanged irrespective of load. 

So total current, this transformer draws from source can be divided into two components, first one is utilized for magnetizing the core and compensating the core loss i.e. Io. It is no-load component of the primary current. Second one is utilized for compensating the counter flux of the secondary winding. It is known as load component of the primary current. Hence total no load primary current I1 of a electrical power transformer having no winding resistance and leakage reactance can be represented as follows

I1=I0+I2'

Where θ2 is the angle between Secondary Voltage and Secondary Current of transformer. Now we will proceed one further step toward more practical aspect of a transformer.

Induced EMF equation for transformer is given  E=4.44f Om(E/f=4.44Om=constant) or for any transformer E/f is constant, Om, the maximum working flux density, or primary induced EMF, E1=4.44fOmN1. For working flux density depending on B-H curve of material used, the H in amper turn(AT) could be obtained, and would give the magnetizing current for the given turn, N1, ((Im)the 90 degree lagging component of current) needed, for the Om, hysteresis area of the material decides hysteresis  loss, and stamping thickness decides eddy current(Ie), the in phase component with applied voltage. Thus total no load current could be Io=Ih+Ie., so slection of core material(CRGO) and to stamping thickness is important in reducing no load current. Refer my related, answer on time line and paper," CT performance for Inrush ...."..

if a transforms fed a non-linear load, due to many harmonic content in currents, the transforms may be led to hotspot point,.

Do you ask about magnetizing inrush current? If so, you should care on magnetic saturation due to residual magnetism and the injection phase of the AC power supply. To dull the rising of the current waveform, a circuit breaker with an input resistance contact is used in field.

Power transformers are in parallel connected to the network and the following holds:

- changes on the secondary side do not influence the primary voltage

- magnetizing current depends on the primary voltage and is not effected by changes in the secondary side (which is completly opposite to CTs)

- secondary voltage depends on the primary voltage

-secondary current (when primary voltage is fixed) depends on the load

When a transformer is unloaded, the secondary current is zero and primary current is equal to the magnetizing current. Since unloaded transformer is a high impedance, this current is low. By switching in the transformer, inrush currents takes place which depend on the type of magnetizing curve. When it goes into saturation, the current increases.

I assume that you develop a transformer model for higher frequencies. However, it is important to know how you model the transformer? Do you take the saturation into account and how?

your question:

"please let me know what is the effect of winding and load on primary and secondary of a transformer and how can i reduce the current in constant voltage?  "

If you think on the voltage, then the winding impedance and load have little to do with the secondary voltage. The induced voltage as mentioned above is: E2~ 4.44*f*S*B*N2 and is mainly determined by the N2. The transferred power from the primary to the secondary side will be P2=E2*I2. At the same time the transferred power is determined by the load, P2=I2^2(Z2+Z). where Z2 is the LV winding impedance which is low.

Thanks M. Popov . your explanation is very useful.