Power quality Problems and mitigation techniques (EX-802 (A)) - Important Questions

Define power quality and explain the reasons for increased concern about power quality.

What are the solutions for power quality problems? How can you check good quality of electrical power?

What is voltage fluctuation and why do lights dim when large appliances switch on?

What are voltage sag and swell? Explain the difference between voltage surge and swell.

Briefly explain the causes of power quality disturbances.

What are the major power quality issues? Explain in detail.

Explain the benefits of power factor correction and where power factor correction capacitor banks can be installed.

What do you mean by flexible in flexible AC transmission system? Why capacitance is taken as shunt in Transmission lines?

What is the basic principle of shunt active filter? Why do we pay a reactive power compensation penalty?

Compare SVC vs STATCOM and differentiate between an active power filter and a STATCOM.

Write short notes on selected power quality topics: non-linear loads, sources of transient overvoltages, problems mitigated by UPQC, and operation of harmonic analyzer.

Write short notes on classification and working of passive series compensation.

Explain the operation of DSTATCOM with a neat sketch.

Explain the power quality problems caused by the reactive power component of currents.

Explain the principle, working and operation of UPQC.

What are the advantages of UPQC?

How the UPQC are classified? Explain briefly.

Compare the operation of UPQC and DSTATCOM.

Explain what power surges / spikes and impulse voltages are, why they occur, and methods to protect high-voltage and electrical equipment including surge protectors and safe working practices.

What is a voltage sag protector? Why is the protection scheme needed for a power system?

What commonly causes transient voltages? Explain the factors affecting transient recovery voltage.

Why is the zero-voltage crossing optimal for harmful transient mitigation, e.g., overvoltage when switching capacitor banks at a substation?

Mention the harmonic sources from industrial loads and commercial loads.

Explain the fundamentals of waveform distortion.

Discuss about the sources of sags and interruption and Describe the mitigation of voltage sag.

Explain how the voltage sag performance is estimated?

Define harmonics, harmonic indices, crest factor, TDD, THD, and interharmonics.

What is the best method to eliminate Harmonics in a Power System? How can filters reduce harmonics?

What is a shunt active filter? What are the advantages and disadvantages of an active harmonic filter?