What is a correction factor?

Correction factor in electrical engineering refers to the factors added to the various existing equations. The electrical installations consist of various electrical components. The correction factors are necessary to compensate for the errors obtained during the measurement, installation, or supply of the power.

Errors in measurement

Errors in the measurement are the most common types of error in electrical works. The various types of errors in the measurement are gross errors, systematic errors, and random errors.

Gross errors

The gross errors include all the human errors made while reading and measuring the data or readings. The errors made during calculations are also included in this category. The gross errors in the measurement can be reduced by taking more precautionary measures while recording and reading the data. Also, the number of readings and experimenters can be increased so that more values can be obtained and the average of all the readings can be taken to obtain a more accurate reading.

Systematic errors

The systematic errors are categorized as Instrumental errors, Environmental errors, and observational errors. The instrumental error may occur due to the errors in the construction of the measuring instrument or due to the wrong calibration of the instrument during measurement. Environmental errors occur due to external environmental factors. Due to the surrounding temperature, pressure, humidity, and so on, errors may occur in setting up the instrument or measuring the readings. The observational errors may occur due to the wrong observations. The systematic errors may be reduced by performing tasks more carefully using more accurate instruments in an ideal environment.

Random errors

The random errors are also known as residual errors. The random errors occur in the electrical instruments due to very small changes happening due to the fluctuations while moving from one measurement to another. The random errors can be reduced by properly using the instrument.

Power Factor Correction

The power factor correction is an important technique used in the power system to increase the power factor of a power supply. The current flowing from the source to the load fluctuates due to various causes. To rectify the fluctuations or distortions caused in the power supply system, power correction factors are used.

Power Factor

The power factor is an important parameter related to the Alternating Current (AC) power system in electrical engineering. The power factor is defined as the ratio of real power to apparent power. Real power, also known as active power is the actual power that is used by the loads such as transformers, generators, induction motors, and so on.

Apparent power is the total power flowing in the circuit. The apparent power is the sum of the active power and the reactive power. Reactive power is the useless power that flows back and forth between the source and the load and causes an extra burden on the power supply system. The power factor ranges from -1 to +1.

The value of the power factor less than +1 indicates that the voltage and current of the circuit are not in phase. The negative values of the power factor show that the loads attached to the circuit are generating power and sending it back to the source or there are some other distortions in the supply. The load having a low power factor requires more current to transfer the required amount of power than the load having a high power factor. Also, much energy is wasted in such a process and the cost of equipment required to be installed for carrying such high currents is also more. So, the process becomes uneconomical. Hence, a larger value of the power factor is always preferred.

Power factor correction for linear loads

For the linear loads, the power factor correction is applied by the electric power transmission utilities to increase the power factor and reduce the cost of supply. In Alternating Current (AC) circuits, the power factor is increased to come closer to 1 by diverting the reactive power produced in the circuit or by absorbing it. This can also be achieved by installing the capacitors and inductors in the circuit to discontinue the capacitive and inductive effects of the loads. Also, the inductors absorb the reactive power, and the capacitor supplies it.

Power factor correction for non-linear loads

For non-linear loads, three types of power factor corrections are used - Passive power factor correction, Active power factor correction, and Dynamic power factor correction. In passive power factor correction, at the Alternating Current (AC) input, the harmonic filter is used and a resonance circuit is formed with the capacitor and inductor. In the active power factor correction, a control circuit is provided in the Alternating Current (AC), which adjusts the duty cycle and switch timings. In the dynamic power factor correction, semiconductor switches are used which connect and disconnect quickly when required to improve the power factor.

A true power correction factor

The electric metering installation consists of various equipment and components. All the components can show some sort of distortions while working and cause errors. To rectify these errors while measuring the actual true power, a correction factor is applied while measuring the power. The correction factor is also known as the final correction factor and it includes all the correction factors of each component. The true power is given as -

True Power = Measured Power x Final Correction Factor x N_E x N_I

where N_E is the voltage transformer ratio and the N_I is the current transformer ratio

The true power measurement is done separately for the active power and the reactive power.

Context and Applications

The correction factor is taught in the following courses-

• Bachelors of Technology (Electrical Engineering)
• Masters of Technology (Power System and Power Electronics)

Practice Problems

Q1. Which of the following are not a type of measurement errors?

a) Gross errors

b) Instantaneous errors

c) Systematic errors

d) Random errors

Answer- b

Explanation- Instantaneous errors are not a type of measurement errors.

Q2. Which of the following is not categorized under systematic errors?

a) Instrumental errors

b) Environmental errors

c) Passive errors

d) Observational errors

Answer- c

Explanation- Passive errors are not categorized under systematic errors.

Q3. What is the range of power factors?

a) 0 to 1

b) -1 to 0

c) -1 to +1

d) 1 to 2

Answer- c

Explanation- The power factor ranges from -1 to +1.

Q4. What does the value of the power factor less than +1 indicate?

a) The voltage and current of the circuit are not in phase.

b) The voltage and current of the circuit are in phase.

c) The circuit is purely resistive

d) The circuit is purely inductive

Answer- a

Explanation- The value of the power factor less than +1 indicates that the voltage and current of the circuit are not in phase.

Q5. In which of the following power factor correction, a control circuit is provided?

a) Active power factor correction

b) Passive power factor correction

c) Dynamic power factor correction

d) Instantaneous power factor correction

Answer- a

Explanation- In the active power factor correction, a control circuit is provided.