Phep Chapter 27 Flashcards
A fuse may serve the same purpose and isolating a fault as a
Circuit breaker
From the two below list of fuses characteristic, select the one that is not true
All fuses are completely non-repetitive in design
The primary reason for not replacing a blown fuse with a piece of copper wire is because
The desire circuit protection against overload, may be lost
The term zone of protection applies, mostly nearly to the isolation of your faulted equipment
Throughout the entire power system
A device which contacts and one circuit are operated by a change in conditions in the same or other circuit is called a
Relay
Protective relay in general must be able to ?
All of these
Protective relay may be classified in all of the below ways except for
According to a manner in which they are connected in circuits
An induction-disc time overcurrent relay ?
Is adjusted separately for the degree of overcurrent at which it operates in also for the amount of time delay
Differential current relays are designed and installed to protect against
Internal fault
When is CT’s are used with protective relays direction of current flow in the transformer wind (polarity Marks)
Must be careful observed for relay which depends on interaction of two currents for their action
All of the following statements concerning the schematic shown fig 28 are true except for
The position of pallet switch indicate that the OCB is in a close position
A really, which would normally respond to change and circuit admittance, impedance and reactive is called a
Distance relay
Polyphase rotation equipment may be protected against single phase operations by using a
Phase-balance relay
The protective device for a motor branch circuit should
Not be of the instantaneous type
The indication time over current relay has which of the following characteristics?
Both A and B
