What is a Vector grouping

Assignment Help Electrical Engineering

Reference no: EM132512165

Assignment - Electrical Engineering Questions

Q1. (a) What is a Vector grouping?

(b) How does the knowledge of vector grouping assist in connecting transformers to operate in parallel?

(d) What are the only phase displacements in degrees with which it is possible to parallel the secondaries of two transformers?

(e) Draw the phase relationships and connections for

(i) Dd0 connection

(ii) Yy6 connection.

Q2. (a) Name the types of on-load tap changer.

(b) Which is the most commonly used and why?

Q3. (a) What is the advantage of monitoring winding temperature as a method of overload protection?

(b) Name two other types of overcurrent protection.

Q4. (a) What is a conservator?

(b) How does this device protect against pollution of the transformer oil?

Q5. List the symbols, and their meaning, used to classify the methods of cooling a transformer and state the types of cooling of an ONAF transformer.

Q6. Describe, with the aid of a diagram, the process involved in tap changing using a centre-tapped reactor.

Q7. (a) Describe, with the aid of a diagram, the method of operation of a Buchholz relay.

(b) State which faults can be detected by this relay and in what way they activate the relay.

Q8. An oil-filled transformer has a c.m.r. of 500 kVA which allows it to run continuously in an ambient of 35^oC with an oil temperature rise of 50^oC. The transformer has a time constant of 1.5. hours and the ratio of copper losses to iron losses at c.m.r. is 1.5:1.

After switch-on, the transformer supplies a load of 600 kVA for one hour and the load then rises to 750 kVA. Calculate the period of time that the transformer can supply this load without exceeding its rated maximum temperature. Sketch the heating curves for the two loads.

Reference no: EM132512165

Questions Cloud

When recording accounting entry for borrowing typically show : When bonds are issued by a company, recording the accounting entry for the borrowing typically shows an increase in assets and an increase in liabilities

Explain how these policies would affect the economy : Currently the U.S. economy and the world economy are in recession caused by the COVID-19. Trump administration returns tax money to tax payers

Operation management : Paul Fenster owns and manages a chili-dog and softdrink stand near the Kean U. campus. While Paul can service 30 customers per hour on the average (m),

What makes us increase our liquidity preference : a. What is liquidity preference, and what makes us increase our liquidity preference?

What is a Vector grouping : What is a Vector grouping? What additional information is needed to ensure that transformers are capable of parallel operation

Which the journal entry would include : At any bond interest payment date regarding bonds that have been issued at a premium, the journal entry would include Debit Bond interest expense

Types of keys used during the encryption process : Discuss all the possible types of keys used during the encryption process. Find more efficient Wireless security protocol than WEP.

Find the bond market to investors at an amount : 7%, a $500,000, 5% stated rate, 20 year bond issue that pays interest semiannually would sell in the bond market to investors at an amount

Explain why the money demand curve is negatively : In ISLM theory, the money demand curve is negative sloped and flattens out at extremely low interest rates.

User Account

All Pages