Power System Protection Basics - 2

Power System Protection S.A.Soman Overcurrent Protection Principle Directional Overcurrent Protection

Distance Protection Principle

Differential Protection Principle For Transmission Lines

Power System Protection S.A.Soman Department of Electrical Engineering IIT Bombay

For Tapped Lines For Transformers For Busbars

Summary

Power System Protection

Protection Paradigms - Apparatus Protection Power System Protection

1

Overcurrent Protection Principle Directional Overcurrent Protection

2

Distance Protection Principle

3

Differential Protection Principle For Transmission Lines For Tapped Lines For Transformers For Busbars

4

Summary

S.A.Soman Overcurrent Protection Principle Directional Overcurrent Protection

Distance Protection Principle

Differential Protection Principle For Transmission Lines For Tapped Lines For Transformers For Busbars

Summary

Protection Paradigms - Apparatus Protection Power System Protection

1

Overcurrent Protection Principle Directional Overcurrent Protection

2

Distance Protection Principle

3

Differential Protection Principle For Transmission Lines For Tapped Lines For Transformers For Busbars

4

Summary

S.A.Soman Overcurrent Protection Principle Directional Overcurrent Protection

Distance Protection Principle

Differential Protection Principle For Transmission Lines For Tapped Lines For Transformers For Busbars

Summary

Protection Paradigms - Apparatus Protection Power System Protection S.A.Soman Overcurrent Protection Principle Directional Overcurrent Protection

Distance Protection Principle

Differential Protection Principle For Transmission Lines For Tapped Lines For Transformers For Busbars

Summary

Principle of Overcurrent Protection When the current in a system exceeds a predetermined value, it indicates the presence of a fault. Relaying decision is based solely on the magnitude of current. Used in radial distribution systems. Overcurrent relaying and fuse protection uses this principle.

Protection Paradigms - Apparatus Protection Power System Protection

1

Overcurrent Protection Principle Directional Overcurrent Protection

2

Distance Protection Principle

3

Differential Protection Principle For Transmission Lines For Tapped Lines For Transformers For Busbars

4

Summary

S.A.Soman Overcurrent Protection Principle Directional Overcurrent Protection

Distance Protection Principle

Differential Protection Principle For Transmission Lines For Tapped Lines For Transformers For Busbars

Summary

Protection Paradigms - Apparatus Protection Power System Protection S.A.Soman Overcurrent Protection Principle Directional Overcurrent Protection

Distance Protection Principle

Differential Protection Principle For Transmission Lines For Tapped Lines For Transformers For Busbars

Summary

Directional Overcurrent Protection Uses both magnitude of current and phase angle information for decision making. Used in radial distribution systems with source at both ends.

Protection Paradigms - Apparatus Protection Power System Protection

1

Overcurrent Protection Principle Directional Overcurrent Protection

2

Distance Protection Principle

3

Differential Protection Principle For Transmission Lines For Tapped Lines For Transformers For Busbars

4

Summary

S.A.Soman Overcurrent Protection Principle Directional Overcurrent Protection

Distance Protection Principle

Differential Protection Principle For Transmission Lines For Tapped Lines For Transformers For Busbars

Summary

Protection Paradigms - Apparatus Protection Power System Protection S.A.Soman Overcurrent Protection Principle Directional Overcurrent Protection

Distance Protection Principle

Differential Protection Principle For Transmission Lines For Tapped Lines For Transformers For Busbars

Summary

Distance Protection The basic principle is that the apparent impedance seen by the relay reduces drastically in case of line fault. If the ratio of apparent impedance to the positive sequence impedance is less than unity, it indicates a fault. This protection scheme is inherently directional. Impedance relay and Mho relay use this principle.

Protection Paradigms - Apparatus Protection Power System Protection S.A.Soman Overcurrent Protection Principle Directional Overcurrent Protection

Distance Protection Principle

Differential Protection Principle For Transmission Lines For Tapped Lines For Transformers For Busbars

Summary

Protection Paradigms - Apparatus Protection Power System Protection

1

Overcurrent Protection Principle Directional Overcurrent Protection

2

Distance Protection Principle

3

Differential Protection Principle For Transmission Lines For Tapped Lines For Transformers For Busbars

4

Summary

S.A.Soman Overcurrent Protection Principle Directional Overcurrent Protection

Distance Protection Principle

Differential Protection Principle For Transmission Lines For Tapped Lines For Transformers For Busbars

Summary

Protection Paradigms - Apparatus Protection Power System Protection S.A.Soman Overcurrent Protection Principle Directional Overcurrent Protection

Distance Protection Principle

Differential Protection Principle For Transmission Lines For Tapped Lines For Transformers For Busbars

Summary

Principle of Differential Protection It is based on the fact that any fault within an electrical equipment would cause the current entering it to be different from the current leaving it.

Protection Paradigms - Apparatus Protection Power System Protection S.A.Soman Overcurrent Protection Principle Directional Overcurrent Protection

Distance Protection

Principle of Differential Protection It is based on the fact that any fault within an electrical equipment would cause the current entering it to be different from the current leaving it.

Principle

Differential Protection Principle For Transmission Lines For Tapped Lines For Transformers For Busbars

Summary

By comparing the two currents either in magnitude or in phase or in both, fault can be determined.

Protection Paradigms - Apparatus Protection Power System Protection S.A.Soman Overcurrent Protection Principle Directional Overcurrent Protection

Distance Protection

Principle of Differential Protection It is based on the fact that any fault within an electrical equipment would cause the current entering it to be different from the current leaving it.

Principle

Differential Protection Principle For Transmission Lines For Tapped Lines For Transformers For Busbars

Summary

By comparing the two currents either in magnitude or in phase or in both, fault can be determined. It is an attractive option if both the ends of the apparatus are located near each other.

Protection Paradigms - Apparatus Protection Power System Protection

1

Overcurrent Protection Principle Directional Overcurrent Protection

2

Distance Protection Principle

3

Differential Protection Principle For Transmission Lines For Tapped Lines For Transformers For Busbars

4

Summary

S.A.Soman Overcurrent Protection Principle Directional Overcurrent Protection

Distance Protection Principle

Differential Protection Principle For Transmission Lines For Tapped Lines For Transformers For Busbars

Summary

Protection Paradigms - Apparatus Protection Power System Protection S.A.Soman Overcurrent Protection Principle Directional Overcurrent Protection

Distance Protection Principle

Differential Protection Principle For Transmission Lines For Tapped Lines For Transformers For Busbars

Summary

Differential Protection for Transmission Lines Its implementation requires a communication channel. It is extremely accurate. Its zone is demarkated by CTs.

Protection Paradigms - Apparatus Protection Power System Protection

1

Overcurrent Protection Principle Directional Overcurrent Protection

2

Distance Protection Principle

3

Differential Protection Principle For Transmission Lines For Tapped Lines For Transformers For Busbars

4

Summary

S.A.Soman Overcurrent Protection Principle Directional Overcurrent Protection

Distance Protection Principle

Differential Protection Principle For Transmission Lines For Tapped Lines For Transformers For Busbars

Summary

Protection Paradigms - Apparatus Protection Power System Protection S.A.Soman

Differential Protection for Tapped Line Overcurrent Protection Principle Directional Overcurrent Protection

Distance Protection Principle

Differential Protection Principle For Transmission Lines For Tapped Lines For Transformers For Busbars

Summary

Protection Paradigms - Apparatus Protection Power System Protection

1

Overcurrent Protection Principle Directional Overcurrent Protection

2

Distance Protection Principle

3

Differential Protection Principle For Transmission Lines For Tapped Lines For Transformers For Busbars

4

Summary

S.A.Soman Overcurrent Protection Principle Directional Overcurrent Protection

Distance Protection Principle

Differential Protection Principle For Transmission Lines For Tapped Lines For Transformers For Busbars

Summary

Protection Paradigms - Apparatus Protection Power System Protection S.A.Soman Overcurrent Protection Principle Directional Overcurrent Protection

Distance Protection Principle

Differential Protection Principle For Transmission Lines For Tapped Lines For Transformers For Busbars

Summary

Differential Protection for Transformer CTs are selected in such a way that under normal conditions the scaled CT currents will match in magnitude. Under fault condition, differential current will flow through the overcurrent relay. Overcurrent relay pick up is set above the no load current value.

Protection Paradigms - Apparatus Protection Power System Protection

1

Overcurrent Protection Principle Directional Overcurrent Protection

2

Distance Protection Principle

3

Differential Protection Principle For Transmission Lines For Tapped Lines For Transformers For Busbars

4

Summary

S.A.Soman Overcurrent Protection Principle Directional Overcurrent Protection

Distance Protection Principle

Differential Protection Principle For Transmission Lines For Tapped Lines For Transformers For Busbars

Summary

Protection Paradigms - Apparatus Protection Power System Protection S.A.Soman Overcurrent Protection Principle Directional Overcurrent Protection

Distance Protection Principle

Differential Protection Principle For Transmission Lines For Tapped Lines For Transformers For Busbars

Summary

Differential protection for Busbar If the fault is external the algebraic sum of the currents entering the bus is zero. If the fault is on the bus the sum is not zero.

Protection Paradigms - Apparatus Protection Power System Protection S.A.Soman Overcurrent Protection Principle Directional Overcurrent Protection

Distance Protection Principle

Differential Protection Principle For Transmission Lines For Tapped Lines For Transformers For Busbars

Summary

Summary Basic Principle of Overcurrent Protection. Directional Overcurrent Protection. Distance Protection. Differential Protection.

Applications of Apparatus Protection.