Protective measures

Question 1

3 Protection principles in low voltage installations

Answer 1

Question 2

Protection principles in low voltage installations

Visualization

Answer 2

Question 3

TN-S System

Low voltage grid types

Answer 3

Question 4

TN-C System

Low voltage grid types

Answer 4

Question 5

TN-C-S System

Low voltage grid types

Answer 5

Question 6

TT system

Low voltage grid types

Answer 6

Question 7

IT system

Low voltage grid types

Answer 7

Question 8

Faults in distribution grids - Introduction

Classification of faults

Answer 8

Question 9

Detection of short circuit currents

Faults in the distribution grids

Answer 9

Question 10

Neutral point treatment

Faults in the distribution grids

Answer 10

Question 11

Requirements for protective devices

Answer 11

Question 12

Protection principles in public distribution grids

Answer 12

Question 13

Overcurrent protection: Fuses

Answer 13

Question 14

Overcurrent protection: Inverse time relay (ITR)

Answer 14

Question 15

Overcurrent protection: Definite time relay (DTR)

Answer 15

Question 16

Distance protection

Protection requirements, principles and coordination

Answer 16

Question 17

Differential protection

Protection requirements, principles and coordination

Answer 17

Question 18

Protection coordination

just the overview, may need to add slides

Answer 18

Question 19

Challanges in future distribution grids

Answer 19

Question 20

Adaptive protection concepts

Answer 20

Question 21

Protective measures: Summary

Answer 21

Question 22

Name and explain three protection principles in low voltage installations

Exercise 6 Task 1.1

Answer 22

1.1 Name and explain three protection principles in low voltage installations.

• Overcurrent protection: Detection of currents higher than operational currents
  avoiding overloading or damage due to short circuits
• Fault current protection: Fault currents smaller than operational currents are
  detected by summing up the three line currents and the neutral conductor current.
  If the sum is non-zero, a fault current is flowing to ground potential. The fault current protection is thus advantageous for the protection of human beings.
• Isolation monitoring: Damages to the electrical isolation can be detected by
  measuring the three phase-to-ground voltages. Isolation monitoring is suitable for systems with isolated neutral point, as an isolation failure will not lead to a large hort circuit current

Question 23

Name the protection principle of a residual current device (RCD) and a fuse

Exercise 6 Task 1.2

Answer 23

• Residual current device: fault current protection
• Fuse: overcurrent protection

Question 24

Exercise 6 Task 1.3

Answer 24

Question 25

Explain two advantages of a TN-S system over a TN-C system.

Exercise 6 Task 1.4

Answer 25

Question 26

Solve Exercise 6 Task 2

Question 27

Name three protection principles in distribution grids.

Answer 27

• Overcurrent protection
• Distance protection
• Differential protectio

Question 28

Name three protection principles in distribution grids

Exercise 3.1

Answer 28

Question 29

Name and explain the protection requirements in distribution grids

Exercise 3.2

Answer 29

Question 30

Name three advantages of digital overcurrent relays over fuses

Exercise 3.3

Answer 30

Question 31

Which protection devices are suitable for protection coordination in ringed and
meshed grids?

Exercise 3.4

Answer 31

Question 32

Exercise 3.5

Answer 32

Question 33

Exercise 3.6

Answer 33

Question 34

Solve Exercise 6 Task 4

Exercise 6 Task 4