Electrical energy systems are the main building blocks of modern life. Many protection mechanisms are used in these systems to provide a safe, sustainable and effective energy flow. Among these mechanisms, the secondary protection system and the secondary protection relay have a critical place.
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Fundamentals of Protection Systems
Protection in electrical energy systems is preferred with the aim of stopping the energy flow safely and preventing damage to the system in the event of any fault or system malfunction. Protection mechanisms in electrical systems are generally divided into two main categories:
Primary Protection: It is the first protection line that detects the fault and quickly disables it.
Secondary Protection: It is activated immediately when the primary protection fails and protects the system.
The secondary protection system provides a backup to the primary protection system. This is a vital feature that improves reliability in energy systems.
What is a Secondary Protection System?
The secondary protection system is a mechanism that prevents damage to the system by stepping in when the primary protection system cannot function for many reasons. The main features of this system are as follows:
Backup Task: If the primary protection system fails, the secondary protection system steps in to stop the energy flow and isolate the fault.
System Security: It provides a safety net for unexpected moments in energy systems.
Timing and Coordination: The secondary protection system generally has a longer waiting time than the primary protection. Thus, primary protection is given a chance.
What is a Secondary Protection Relay?
The secondary protection relay is an important component of this system. It detects problems such as overcurrent, short circuit or grounding that may occur in electrical systems and intervenes to stop them. Some of the main features of secondary protection relays are as follows:
Fault Detection: Secondary relays step in when the primary protection is ineffective and detect the fault.
Sending Signal: The relay transmits the detected fault condition to the opening mechanism or the operator.
Time Setting: The secondary protection relay, which generally has a delayed setting, operates when the primary protection relay is not activated.
Working Principle of Secondary Protection System
The secondary protection system continuously monitors changes in the power system through many sensors and relays. The system operates with the following steps:
Fault Detection: The data received from devices such as current transformers and voltage transformers are analyzed. If an abnormal situation is detected in the system during this analysis, the secondary relays are activated.
Timing and Coordination: A certain time is given to the primary protection relays. If the primary protection problem cannot be resolved within this period, the secondary relays are activated.
Opening the Circuit: The secondary protection relay sends a signal to the circuit breaker and stops the power flow.
Informing the Operator: Detailed information about the fault is transmitted to the operators.
The Importance of Secondary Protection Systems
Durability and continuity are of critical importance in energy systems. Secondary protection systems play a vital role in achieving these two goals. Here are the main advantages of these systems:
Provides Security: Secondary protection is activated when primary protection is ineffective and prevents damage to the system and equipment.
Energy Continuity: Prevents faults from causing larger-scale outages.
Reduces Economic Loss: Reduces costs by preventing sudden faults from causing serious material damage to equipment.
Secondary Protection Relay Types
Secondary protection relays, which are preferred in electrical systems, are designed to detect many faults. Some common secondary protection relay types are as follows:
Overcurrent Relay: Detects and intervenes in overcurrent situations in the system.
Short Circuit Relay: Detects faults caused by short circuits.
Grounding Relay: Activates in times of ground leakage.
Differential Protection Relay: Detects internal problems in devices such as transformers or generators.
Differences Between Secondary Protection and Primary Protection
Secondary protection and primary protection are two basic protection mechanisms used to identify and intervene in electrical systems. Primary protection is the first to intervene in incoming faults that occur in the system and is responsible for cutting off the power flow and works quickly. For this reason, it focuses directly on the fault point and responds instantly. Secondary protection, on the other hand, steps in when primary protection fails to function for any reason and backs up the system. It can cover a wider area compared to primary protection and provides time for primary protection by working with a certain delay. While secondary protection acts as a safety net that accelerates the reliability of the system, primary protection is the first line of defense of the system. These two protection mechanisms work together to provide security, continuity and efficiency in energy systems.
Usage Areas of Secondary Protection System
Secondary protection systems are used in many different areas from energy production to distribution. Some areas of use are:
Transformer Substations: Used to detect and isolate transformer faults.
Generator Protection: Protects the system in cases such as overload or short circuit that may occur in generators.
Industrial Facilities: Used to ensure system durability in industrial facilities that consume high energy.
Distribution Lines: Isolates the system in case of any fault in electrical distribution lines.
Things to Consider in Secondary Protection System Design
Some serious criteria should be taken into consideration when creating a secondary protection system:
Coordination: A suitable order should be provided between secondary and primary protection relays.
Correct Time Setting: A correct delay moment should be determined for the secondary protection system.
Testing and Maintenance: It is important to test, test and maintain the relays in a planned manner.
As a result, the secondary protection system and secondary protection relay play an indispensable role in the safety of power systems. These systems stop the power flow safely in case of faults and provide important assistance to the primary protection system. Secondary protection mechanisms are one of the simple elements to consider for engineers who want to design a reliable energy distribution system.
In order to ensure durability and continuity in modern energy systems, it is of great importance to create, test and regularly maintain secondary protection systems appropriately.
Published On - 5 January 2025