Assertion (A): The lower order harmonics are reduced by using some technique while the higher order harmonics are reduced by using filter.
Reason (R): The cost of the filter is reduced and at the same time transient response is also improved to a great extent.
a)
Both A and R are true and R is the correct explanation of A.
b)
Both A and R are true but R is not the correct explanation of A.
c)
A is true but R is false,
d)
A is false but R is true.
Correct answer is option 'A'. Can you explain this answer?

Question

Assertion (A): The lower order harmonics are reduced by using some technique while the higher order harmonics are reduced by using filter.
Reason (R): The cost of the filter is reduced and at the same time transient response is also improved to a great extent.

a)
Both A and R are true and R is the correct explanation of A.
b)
Both A and R are true but R is not the correct explanation of A.
c)
A is true but R is false,
d)
A is false but R is true.

Correct answer is option 'A'. Can you explain this answer?

Answer

Lower Order Harmonics vs Higher Order Harmonics
Lower order harmonics and higher order harmonics are two different types of harmonics present in an electrical system. Understanding the difference between these two types is crucial in order to effectively reduce their effects.

Assertion (A): The lower order harmonics are reduced by using some technique while the higher order harmonics are reduced by using a filter.
The assertion states that lower order harmonics are reduced using some technique, while higher order harmonics are reduced using a filter. Let's examine this statement in detail.

Reason (R): The cost of the filter is reduced and at the same time transient response is also improved to a great extent.
The reason provided states that the use of a filter reduces the cost and improves the transient response. Let's analyze this reason further.

Explanation:

Lower Order Harmonics
Lower order harmonics refer to the harmonics with lower frequencies, typically the fundamental frequency and its multiples. These harmonics can be reduced using various techniques such as:

1. Passive Filtering: Passive filters, such as inductors and capacitors, can be used to attenuate lower order harmonics. These filters are designed to introduce impedance at specific frequencies, thereby reducing the harmonics.

2. Active Filtering: Active filters use active components such as transistors and operational amplifiers to actively cancel out the lower order harmonics. These filters are more effective in reducing harmonic distortion.

3. Phase Shifting: By introducing a phase shift in the system, lower order harmonics can be canceled out or minimized. This technique is commonly used in power factor correction circuits.

Higher Order Harmonics
Higher order harmonics refer to harmonics with frequencies higher than the fundamental frequency. These harmonics are usually reduced using filters, specifically harmonic filters. Harmonic filters are designed to attenuate specific harmonic frequencies, effectively reducing the higher order harmonics.

Explanation of Assertion and Reason:
The assertion states that lower order harmonics are reduced using some technique, while higher order harmonics are reduced using a filter. The reason provided states that using a filter reduces cost and improves transient response.

The assertion is true because both lower order and higher order harmonics can be reduced using different techniques. Lower order harmonics can be reduced using techniques such as passive filtering, active filtering, and phase shifting. On the other hand, higher order harmonics are typically reduced using harmonic filters.

The reason is the correct explanation of the assertion. Using a filter to reduce higher order harmonics can be a cost-effective solution compared to other techniques. Additionally, by effectively reducing higher order harmonics, the transient response of the system can be improved.

Therefore, the correct answer is option 'A': Both A and R are true, and R is the correct explanation of A.

Answer

The machine operated at 50 H_z.

Synchronous speed N_s

A slip of S = 0.02
N_r = (1 - S) N_s= 980 rpm.

Answer

Lower Order Harmonics and Techniques to Reduce Them
-----------------------------------------------

Lower order harmonics are the harmonics with frequencies that are multiples of the fundamental frequency but have lower multiples. For example, in a system with a fundamental frequency of 50 Hz, the lower order harmonics would include the 2nd harmonic (100 Hz), 3rd harmonic (150 Hz), and so on.

To reduce the lower order harmonics, various techniques can be employed. Some of these techniques include:

1. Phase-shifting transformers: These transformers are used to shift the phase angle of the harmonics, effectively canceling out the lower order harmonics.

2. Active power filters: Active power filters use power electronic devices such as inverters to generate harmonic currents that are out of phase with the harmonics in the system. This cancels out the lower order harmonics.

3. Passive filters: Passive filters consist of passive components such as capacitors, inductors, and resistors arranged in specific configurations to filter out the lower order harmonics.

Higher Order Harmonics and the Use of Filters
--------------------------------------------

Higher order harmonics are the harmonics with frequencies that are multiples of the fundamental frequency but have higher multiples. For example, in a system with a fundamental frequency of 50 Hz, the higher order harmonics would include the 4th harmonic (200 Hz), 5th harmonic (250 Hz), and so on.

To reduce the higher order harmonics, filters are commonly used. Filters are electronic circuits or devices that attenuate specific frequencies or ranges of frequencies. In the case of higher order harmonics, filters are used to attenuate the harmonics with frequencies that are multiples of the fundamental frequency but have higher multiples.

The Use of Filters to Reduce Higher Order Harmonics
---------------------------------------------------

1. Passive filters: Passive filters can be used to reduce higher order harmonics by providing a low impedance path to the harmonics. These filters are typically designed with specific values of inductors, capacitors, and resistors to create a resonance circuit that attenuates the higher order harmonics.

2. Active filters: Active filters, similar to active power filters mentioned earlier, can also be used to reduce higher order harmonics. These filters use power electronic devices to generate harmonic currents that are out of phase with the harmonics, canceling them out.

3. Digital filters: Digital filters are implemented using digital signal processing techniques. These filters use algorithms to sample, process, and modify the harmonic components of the signal to reduce the higher order harmonics.

Assertion and Reason Analysis
-----------------------------

Assertion (A): The lower order harmonics are reduced by using some technique while the higher order harmonics are reduced by using filters.

Reason (R): The cost of the filter is reduced, and at the same time, the transient response is also improved to a great extent.

Both the assertion and reason are true. The assertion correctly states that lower order harmonics are reduced using techniques, while higher order harmonics are reduced using filters. The reason provides additional information about the benefits of using filters to reduce higher order harmonics, including cost reduction and improved transient response. Therefore, the reason is the correct explanation of the assertion.

Therefore, the correct answer is option A: Both A and R are true, and R is the correct explanation of A.

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