Why Power Factor de-grade when we install Solar Power Plant with Grid ?

What is power factor in grid connected solar plant:

“Power factor is a measure of Phase difference between the Voltage and current in an AC power System”. “There is No Power factor in DC"

In purely resistive load (such as an incandescent lightbulb on electric kettle) the current is in phase with Voltage and there is unity PF.

In Inductive loads also Called lagging Loads (Such as induction motors, transformers) the alternating arrant lags behind the alternating Voltage when the current flows into the load.

EPC contractor mostly installing rooftop solar plant as per solar consultant's CSS grid layout. Solar plant SLD includes Solar ACDB DCDB, AC Combiner box, Busbar box, Metering box and extension with DG-PV Synchronizing panels. But most important factor is electricity bill and saving of money using APFC panel with improvement of PF.

Power triangle:

“A non- Unity power factor means a load is consuming both active and reactive power”

Active power (also known as real on true power) it is useful Component of the AC power and is what Contributes to the work done in a system. (notation of a motor shaft on the glowing of a light bulb)

Reactive Power oscillates between the generation Source and the load, and does no work in the system. Reactive power ls however needed to maintain the Voltage in a system, provide magnetizing power to motors and facilitates the transmission of the active power thorough the AC Circuit.

Apparent Power (VA) = (Real Power) + (Reactive Power)

A Common analogy 01 AC Power is to a glass of bear as Show Reactive Power i analogous with the head of the bean.

while the liquid been is active power (that does the Power) i giving apparent Power as everything Contained in the glass.

“Power factor i the Cosine of the Phase angle in a. power tangle."

“It is defined as the ratio between the active Power (w) and apparent Power (VA),”

Power factor will vary between 0 and 1, and be either leading on lagging

Power (W) Power Factor (Cas) = Apparent Power (VA)

Power Factor and the Grid:

The Supply of Reactive Power is very Important in an AC power grid he amount Of Reactive power produce by generator must closely match that which are Consumed.

* A leading Power factor in the System (du to capacitive load) Causes k Voltage to Rise."

A lagging Power factor in the System (due to Inductive load) Causa Voltage to fall."

Of the reactive power is either under or oven Supplied the Voltage 0f the network may rise on fall to a point where generations must Switched. Of to protect themselves thane by decreasing the generation and caused further problems.

A Can be seen from the phase diagram, increasing the reactive power increasing the apparent power but has no effete on the active power.

This means that the generators in the System must Supply more apparent power even though thane is additional work done by the system (as there increase in active power).

Therefore, power factor l best Corrected locally. The most Common way for this to be performed s by using bonks of Capacitors Rat Can be Shunted. In and out of the System depending on the Operation the load.

Residential Customers do not energy to warrant the Additional Cost of metering equipment to measure power factors

Lange industrial and commercial Customers however billed for consuming power ad a poor power factor:

Frere is therefore an incentive for these customers to improve the power factor of this loads and reduce the amount of reactive power they draw from the grid    

Power Factor and Grid Connected PV Systems:

Most grid Commented PV inverters are only setup to inject power at unity power factor, meaning they only produce active power. In effete this reduces the factor, and the grid Supplying less active power, but the same amount of reactive power.

Consider the Situation in Figure-A the factory is Consuming 100kw of active power and 32.9 KVAR of Reactive power resulting in power factor Of O:95 lagging.

This factory was to install a 60kW PV system that exported at a unity power factor only the active power that is from the would be affected imported active Power from the grid.

While the reactive power imparted from the grid remains constant at 32.9 KVAR

 As can see from the Phase diagram this has the effect of reducing the Power factor to 0.77-lagging

The problem of poo4 power factor however can be addressed through the Selection of appropriate inverter products. Inventers with reactive power Control can be Configured to produce both active and reactive power Factors. This means that the power from the load can be kept within reasonable limits

Figure C Shows the factory with the inverter set to a power factor of 0:95- leading

The PV system is now power producing 57kw to active power and 18:7 KVAR Of Reactive power, the amount of Power (both active and reactive power) from grid. The resultant power factor is therefore maintained at what it was originally at 0:95 - lagging would be possible to Configure the inverter to produce more reactive power and bring Unity power factor.

The optimal power factor that the inverter is programmed to export at will depend on the energy Contract of Consumer. Utilities Can bill industrial and Commercial Customers for the energy they Consume, their peak demand and their power factor any Solar system.

For example, it may be financially beneficial to reduce the amount of active power drawn from the grid at the expense of increased changes due to a poon power factor

Solution of power factor improvement in grid:

A Good LT panel manufacturer can design how to improve power factor by using summation type CT in GRID and Solar Power plant main Incomer. Combination of multiple capacitor bank can improve power generation in electric power in rooftop or largest solar plant.

The summation CT consists of two or more primary windings which are connected with the feeders to be summated, and a single secondary winding, which feeds a current proportional to the summated primary current.


Integrating Solar power system into national grids can reduce transmission and distribution line losses, increase grid electricity of demand, lower generation costs, and reduce requirements to invest in new utility generation capacity. The goal of this paper was to review the current and future discussions regarding generation and unification of large-scale solar generation into a conventional fossil fuel dominated grid. Most of the research has been shown positive results on combination.

The effects of this unifications on system stability and security should therefore be considered carefully even before installations of plant. The use of advanced unification technologies should be considered before plant installation, this will help the generation and distribution company to foresee the possible impact of PV system and generation on system stability.