kVA to kW and kW to kVA Conversion Calculator

Convert apparent power in kilovot-amps (kVA) to real power in kilowatts (kW) and real power in kilowatts (kW) to apparent power in kilovot-amps (kVA) using our conversion calculator.

Learn more about the relations between Amps (A), Voltage (V), Watts (W), Volt-Amps (VA), and other units often used not only in Electrical Engineering but also in many other fields.

Published: March 12, 2024.

How to Convert Kilovolt-Amps (kVA) to Kilowatts (kW)

The real power P(kW) equals the apparent power S(kVA) multiplied by the phase shift (often labeled as "Power Factor" PF):

P(kW) = S(kVA) * PF

Note: phase shift must be 1 or less.

How to Convert Kilowatts (kW) to Kilovolt-Amps (kVA)

The apparent power S(kVA) equals the real power P(kW) divided by the phase shift (Power Factor: PF):

S(kVA) = P(kW) / PF

Again, the phase shift must be 1 or less.

Real Power vs. Apparent Power

Real power and apparent power are two fundamental concepts used to describe power in AC (alternating current) circuits, each providing different insights into how electrical energy is managed and utilized.

Real Power (Active Power)

• Definition: Real power is the power that actually performs work in an AC circuit. It is the component of power that results in the actual consumption of energy, converting electrical energy into other forms like mechanical power, heat, or light.
• Measurement Units: Watts (W).
• Calculation: Real power (P) is calculated as P = V * I * cos(φ), where V is the voltage across the load, I is the current through the load, and cos(φ) is the power factor, representing the phase difference/shift between the current and voltage.
• Significance: Real power is directly related to the useful work done by an electrical system and is a critical factor in determining the efficiency of electrical devices and systems.

Apparent Power

• Definition: Apparent power is the total power supplied to an AC circuit, representing the combination of real power and reactive power. It reflects the total amount of energy being transmitted from the source to the load without distinguishing between the energy that does work and the energy stored and then returned to the system.
• Measurement Units: Volt-amperes (VA).
• Calculation: Apparent power S is calculated as S = V * I, where V is the RMS voltage and I is the RMS current.
• Significance: Apparent power is crucial for the design and sizing of electrical infrastructure, such as transformers and wiring, to ensure they can handle the total power flow through the system. It indicates the capacity required to transmit the electrical power, including both working and non-working components.

Note: RMS stands for Root Mean Square. It's a mathematical method used to determine the effective value of an alternating current (AC) or voltage. The RMS value of an AC signal is the equivalent direct current (DC) value that delivers the same amount of power to a load as the AC signal over one cycle. RMS values are especially important in electrical engineering, as they provide a meaningful measure of the voltage and current in circuits that alternate, ensuring accurate power management and device safety.

Key Differences

• Nature of Power: Real power denotes the actual consumption and conversion of electrical energy into work, while apparent power combines this real consumption with reactive power, which is cyclically stored and released by the circuit's reactive components (capacitors and inductors).
• Units of Measure: Real power is measured in watts, reflecting the energy conversion rate, whereas apparent power is measured in volt-amperes, indicating the total power flow.
• Practical Implications: Real power impacts the efficiency and operational costs of electrical systems, being directly related to the work performed. Apparent power is more about the capacity of the system to deliver the energy, including both the energy that does useful work and the energy that does not contribute to work but must still be managed by the system.

Understanding the distinction between real and apparent power is essential for electrical engineering, especially for the design, operation, and optimization of AC power systems, ensuring both efficient use of energy and the integrity and capacity of electrical infrastructure.