How does reactive power increase voltage

The most important cause of positive reactive power is the reactance of power lines themselves. Transformers, which rely on inductors, also inject positive reactive power into the lines. At the grid edge, inductive appliances such as electric motors and refrigerators contribute positive reactive power as well. Because higher reactive power equates to higher voltage, too much positive reactive power in one part of the network can cause voltage to drop precipitously.

In order to compensate for the reactance of power lines, transformers, and inductive appliances, there needs to be a sufficient injection of negative reactive power. This service can be provided by power plants, albeit at the expense of real power production and constrained by transmission capacity.

Alternatively, negative reactive power can be used downstream to improve power flow. For example, capacitors placed downstream near transformers and inductive loads can be used to mitigate voltage drops where most needed. Some electrical devices such as smart inverters can also stabilize reactive power locally. Although reactive power is essential for voltage stability in transmission, too much positive reactive power in the distribution system affects energy efficiency.

Referring back to the example of the horse and the railcar, increasing the angle of the pull lowers the amount of real power applied to the railcar. In , Consolidated Edison in New York introduced a reactive-power charge to penalize large electric customers with inefficient induction equipment.

Reactive power—the delay between voltage and current at a given point—is subjected to transmission constraints. As a result, it is often necessary to produce reactive power close to the location where it is needed.

Additionally, some appliances such as electric motors need negative reactive power to run their magnets properly. Supplying reactive power locally is thus much more effective than producing it from afar. This is where distributed energy resources may bring significant benefits to reactive power regulation. In January , the California Public Utilities Commission issued a technical report recommending standards on smart inverter capabilities.

PJM has also issued strong statements supporting smart inverters for the regulation of reactive power. Your email address will not be published. Reactive power is electricity that is both useless and necessary Electrical power P , in Watts is composed of voltage V, in Volts and current I, in Amps.

Power factor example: using a horse and a railcar Source: Consolidated Edison As shown in the above image, picture a horse that is pulling a railcar from the side of the track. Vectors for reactive currents are 90 degrees out of phase with the applied voltage. However the phase angle of the load current has an effect on the total voltage drop. The addition of capacitors may cause a reactive voltage drop. The addition of capacitors may cause a cancellation of part or all of an inductive voltage drop with a net voltage rise.

The addition of capacitors may cause increased excitation of the supply generator with an attending rise in voltage. Bill "Why not the best? Consider a simple series circuit consisting of an AC voltage source, resistor, inductor and a load either purely resistive or purely capacitive.

Select the component values such that in Case 1 resistive load , the current lags the voltage lagging power factor , and for Case 2 capacitive load , the current leads the voltage leading power factor. Now assume the voltage across the load to be 1 per unit and solve for the voltage required by the AC voltage source using vector math and KVL. For Case 1, the inductance will draw lagging vars from the source and more than 1 per unit voltage will be required from the source to overcome the voltage drop to maintain 1 per unit voltage across the load.

For Case 2, the capacitor will provide leading vars to the circuit and less than 1 per unit voltage will be required from the source since the capacitor will cause a voltage rise at the load. Hope this helps some! Changing the current angle by increasing the load power factor with capacitors will reduce the amount of source voltage VS needed to get the load voltage VR.

This can be seen by drawing the voltage and voltage drop vectors. See attached diagram. In the first vector diagram, the current lags the load voltage by the angle theta. Graphically, you can see that for the same VR, the second diagram has a smaller VS, meaning less voltage drop. If the IR-IX voltage drop vectors are rotated even more counterclockwise, representing the load current leading the load voltage, VS will get smaller and after a lot of rotation, it will be smaller than VR voltage rise from VS to VR.

Without going into phasor diagrams, I'll give you the cent version of this. If you have a high-current load that is primarily inductive, the high-magnitude current is going to cause the voltage to drop between the source and the load due to the fact that the lines supplying the load have impedance.

If you can supply the reactive current very close to the load using a cap bank, for instance , the reactive part of the current does not have to travel the length of the line between the source and the load, thus it does not contribute to the voltage drop. I believe that rockman has generating capability. With more than one source of power simple solutions may not be adequate. It is possible and not uncommon for reactive power to flow in the opposite direction to real power.

Reactive power may have an effect on the excitation and resulting voltage. Read about how California Senate Bill may potentially impact natural gas prices in Southern California. All Rights Reserved. Products and services vary depending on region or market.

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