The protections system in electrical power system plays vital role to maitain good quality electrical supply. In our everyday life, we use various electrical devices. These electrical devices have become an integral part of our lives. All of them operate using electrical power, which is common for all types of consumers ,whether domestic, commercial, or industrial.
Typically, power for all consumers is generated at a central location, unless they have their own individual setup. Moreover, consumers often receive electrical energy from a common distribution station. Therefore, if any problem arises at a consumer’s premises, it can affect not only the distribution system but also the generation system, ultimately impacting other consumers as well.
Need for a Protection System
Every consumer must receive a continuous power supply without interruption. Otherwise, it can affect both individual and industrial growth, ultimately impacting the nation’s economy. To ensure uninterrupted power supply, electricity boards interconnect sources and consumers through grids.
If a fault occurs in any part of the system, it can affect adjacent systems as well. Therefore, it is essential to protect the power system from abnormal conditions to ensure maximum power supply continuity.
A good protection system should operate quickly, and faults must be cleared within fractions of a second. Alternatively, the faulty section should be isolated to maintain the continuity of supply to the rest of the system. The longer a fault persists, the more it affects equipment and reduces overall efficiency.
The protection system ensures that the faulty section is automatically switched off during fault conditions and can also be manually operated under normal conditions. Control systems can be operated locally or remotely. Equipment that can both isolate faulty sections and perform switching operations under normal conditions is known as switchgear.
Important Functions of a Protection System
A protection system should fulfill the following key functions:
1. Quick Operation
When a fault occurs in a section of the power system, it can damage associated equipment. To minimize damage, the switchgear must operate as quickly as possible after the fault occurs. The longer a fault stays in the system, the more it can damage transformers, generators, switchgear, and other control equipment. Delayed clearance may also cause the fault to spread to healthy sections of the system.
2. Reliability
Reliability refers to the ability of the system to operate under predetermined conditions. Without reliability, protection systems may become ineffective or even a liability. A reliable system ensures faults are cleared when needed and avoids false operations.
3. Discrimination
A protection system must be able to distinguish between faulty and healthy parts of the system. It should isolate only the faulty section without affecting the rest of the system. This selective isolation increases the overall continuity and stability of power supply.
4. Provision for Instrumentation and Control
For metering and remote control purposes, the protection system should include provisions for connecting instrument transformers such as current transformers (CTs) and potential transformers (PTs). This makes monitoring and remote control more effective and feasible.
A protection system that incorporates all the above qualities is considered a good and efficient power protection system.
