kVA Calculator

Current (I):

Voltage (V):

Power System:

Apparent Power (S, kVA):

1. What is a kVA Calculator?

Definition: This calculator computes the apparent power ( $S$ ) in kVA for electrical systems, which represents the total power in an AC circuit, combining both real and reactive power.

Purpose: It is used in electrical engineering to size transformers, generators, and other equipment in single-phase and three-phase power systems.

2. How Does the Calculator Work?

The apparent power is calculated using the following formulas:

Single-Phase:

S = \frac{I \times V}{1000}

3-Phase (Line-to-Line):

S = \frac{\sqrt{3} \times I \times V_{L L}}{1000}

3-Phase (Line-to-Neutral):

S = \frac{3 \times I \times V_{L N}}{1000}

Where:

$S$ is the apparent power (kVA)
$I$ is the current (Amperes, A)
$V$ , $V_{L L}$ , or $V_{L N}$ is the voltage (Volts, V)

Steps:

Enter the current ( $I$ ) and select a unit (mA, A, kA)
Enter the voltage ( $V$ ) and select a unit (mV, V, kV, MV)
Select the power system (Single-Phase, 3-Phase Line-to-Line, or 3-Phase Line-to-Neutral)
Convert current to Amperes and voltage to Volts
Calculate the apparent power using the appropriate formula

Display format:

If the value is > 10000 or < 0.0001 (and not zero), use scientific notation (e.g., $1.23456 e - 3$ )
Otherwise, display with 5 decimal places

3. Importance of kVA Calculation

Details: kVA is essential for sizing electrical equipment like transformers and generators, ensuring they can handle the total power demand in a system, including both real power (kW) and reactive power (kVAR).

4. Using the Calculator

Tips: Input positive values for current and voltage. For three-phase systems, ensure you select the correct voltage type (line-to-line or line-to-neutral) based on your measurement.

Examples:

Single-Phase System: $I = 10 A$ , $V = 230 V$ :
- $S = \frac{10 \times 230}{1000} = 2.30000 kVA$
3-Phase (Line-to-Line): $I = 20 A$ , $V_{L L} = 400 V$ :
- $S = \frac{\sqrt{3} \times 20 \times 400}{1000} = 13.85641 kVA$
3-Phase (Line-to-Neutral): $I = 15 A$ , $V_{L N} = 230 V$ :
- $S = \frac{3 \times 15 \times 230}{1000} = 10.35000 kVA$

5. Frequently Asked Questions (FAQ)

Q: What is kVA?
A: kVA (kilo-volt-amperes) is the apparent power in an AC circuit, representing the total power (real and reactive) delivered to the system.

Q: What’s the difference between line-to-line and line-to-neutral voltage?
A: Line-to-line voltage ( $V_{L L}$ ) is the voltage between two phases in a three-phase system, while line-to-neutral voltage ( $V_{L N}$ ) is the voltage between one phase and the neutral.

Q: Why is kVA important?
A: kVA determines the capacity of electrical equipment like transformers and generators, ensuring they can handle the total power demand.

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