ferroresonance

Question 1

When inductive reactance is equal to the capacitive reactance, there is no inductive load impeding the current flow in a circuit.

Answer 1

true

Question 2

Flashovers can occur at the terminals or cutouts of certain types of transformer banks on the open phase(s) when ?

Answer 2

single pole switching is done

Question 3

Ferroresonant conditions cannot occur when switching transformer banks with ? connections in and out of service.

Answer 3

grounded wye primary

Question 4

A 3-phase pad-mounted transformer installation is not susceptible to ferroresonance.

Answer 4

false

Question 5

The symbol for capacitive reactance is ?

Answer 5

Xc

Question 6

For a ferroresonance condition to occur, which factor must be in place?

Answer 6

there must be virtually no resistive load on the circuit

Question 7

Underground cable is a natural ? with the live conductor separated from the other conductor, the grounded sheath, by relatively thin insulation.

Answer 7

capacitor

Question 8

Ferroresonance can occur on a 3-phase transformer installation when there is no (or an extremely small) secondary load on the transformer bank during switching.

Answer 8

true

Question 9

The capacitance generated on ? cable is greater than on 12-kilovolt cable and is more likely to match the reactance of a transformer bank.

Answer 9

20 to 35 kv

Question 10

To avoid ferroresonance, ? of the causes of the phenomenon must be removed.

Answer 10

any one

Question 11

All flashovers from the floating neutral to a transformer tank on a wye bank are due to ferroresonance when closing in the first or second cut-out.

Answer 11

false

Question 12

One way to avoid ferroresonance while switching is to keep about ? or more of the transformer’s nameplate capacity connected as secondary load.

Answer 12

10%

Question 13

To avoid ferroresonance while energizing transformer banks, ?

Answer 13

energize at the transformer cutouts after the cutouts on the branch line or cable dip have been closed

Question 14

A design solution to avoid a ferroresonance condition is to replace a wye-delta three-transformer bank with an open-wye open-delta two-transformer bank of the appropriate kVA rating.

Answer 14

true

Question 15

A ferroresonance prevention action is to use transformers with the primary banked delta and the secondary banked delta with a corner ground.

Answer 15

false

Question 16

The process of saturating the iron (ferrous) core is where the term ferroresonance originates.

Answer 16

true

Question 17

By temporarily grounding the floating neutral of a three-transformer bank wye primary, it will short out the two windings that are part of the series circuit that causes induction (ferroresonance).

Answer 17

true