Pg 136-140 Electrical Grid Distribution Components and Underground Systems

Flashcard study set testing key components of electrical distribution grids, overhead protection devices, voltage regulators, capacitors, gang-operated switches, and underground equipment classifications.

What is the primary function of fused cutout switches on the power grid?

They are installed to protect equipment such as transformers and to protect the main line from faults that occur on a tap line.

How do fused cutout switches indicate that a fault has occurred?

The fuse burns and the fuse holder automatically falls open, allowing lineworkers to quickly locate the fault.

What is the main function of a recloser on an electrical distribution line?

It recloses the line after a temporary fault, which minimizes outage time.

How many times can a recloser attempt to reclose to determine if a fault is temporary or permanent?

Up to $4$ times.

What capability distinguishes newer Smart reclosers from standard reclosers?

They use two-way communication to send status information to the System Operator as well as receive open, close, and lockout instructions.

When does a sectionalizer open to isolate a faulted section of line?

It opens during a momentary period when the line has been de-energized by the recloser.

Why is a sectionalizer coordinated with a recloser near underground line sections?

To keep the recloser from reclosing into an underground fault, which is almost always a permanent fault.

How do lightning or surge arresters protect distribution lines and equipment?

They take the lightning surge and divert it to ground.

How are the connections made on a lightning arrester?

One end of the arrester is connected to phase and the other end is connected to ground.

By what percentage can a voltage regulator increase or decrease input voltage?

It can increase or decrease the input voltage by $10\%$.

How can a lineman determine the current position of a voltage regulator?

By checking the dial indicator located at the top of the unit.

How do capacitors improve circuit efficiency?

They introduce capacitive reactance to counteract the negative effects of inductive reactance introduced by transformers and large customer-owned motors.

What is the advantage of gang-operated switches when breaking regular line load?

All three phases open at the same time, preventing damage to customer-owned, three-phase equipment.

Does the ability of a gang-operated switch to open all three phases simultaneously apply to fault currents?

No, this capability exists only on regular line load, and not on fault currents.

What physical feature distinguishes most gang-operated switches?

The operating handle that extends to the ground.

How must gang-operated switches be opened and closed?

In a fluid and deliberate manner to minimize arcing.

What are the two key classifications for installing underground distribution equipment?

Above ground or padmounted equipment, and below grade or subsurface equipment.

What are the primary benefits and drawbacks of underground distribution systems?

They are preferred for improved appearance and immunity to high winds, ice, and trees, but are costly to install and maintain.

What is the main operational advantage of padmounted equipment compared to subsurface equipment?

Padmounted equipment is visible and much easier to maintain and operate.