Why does back up protection is needed to properly protect the power system?

The backup protection provides the back up to the main protection whenever it fails in operation or its cut out for repairs. The backup protection is the second line of defence which isolates the faulty section of the system in case the main protection fail to function properly.

What is a back up protection?

The backup protection is the second line of defense which isolates the faulty section of the system in case the main protection fails to function properly.

What is the purpose of the protection system?

Primary function of the protective system is to detect and isolate all failed or faulted components as quickly as possible, thereby minimizing the disruption to the remainder of the electric system.

What is back up protection of transformer?

Backup protection of electrical transformer is simple Over Current and Earth Fault protection are applied against external short circuit and excessive over loads. These over current and earth Fault relays may be of Inverse Definite Minimum Time (IDMT) or Definite Time type relays (DMT).

Why does primary protection fail?

The failure of the primary protection occurs because of the failure of the DC supply circuit, current or voltage supply to relay circuit, relay protective circuit or because of the circuit breaker.

What are the causes of failure of primary relaying?

Primary protection may fail due to the following reasons

• Failure of DC supply to the tripping Circuit.
• Failure in relay operating current or voltage.
• Failure in circuit breaker tripping mechanism.
• Failure of main protective relay operation.
• Failure in the wiring of relaying system.
• Failure of CTs or PTs operation.

What are different types of back up protection?

Types of Secondary or backup protection

• Relay Backup Protection.
• Breaker Backup Protection.
• Remote Backup Protection.
• Centrally Co-ordinate Backup Protection.

What is the difference between primary protection and back up protection?

The primary protection is the first line of defense and is responsible to protect all the power system elements from all the types of faults. The backup protection comes into play only when the primary protection fails.

Under what condition back up protection is economically justified?

The cost of back-up protection is justified on the basis of the probability of failure of individual component in the protection system, cost of the protected equipment, the importance of protected equipment, location of protected equipment, etc.

What is primary protection and back up protection?

Primary protection (Main protection) is the essential protection provided for protecting an equivalent/machine or a part of the power system. As a precautionary measure, addition protection is generally provided and is called Backup Protection.

What is the difference between primary and back up protection?