Protection Relays Quiz

What is the function of a protective relay?

• To regulate the voltage in the system

• To isolate the defective element from the system

• To initiate the operation of the circuit breaker

• To measure the electrical quantities in a circuit

What are the fundamental requirements of protective relaying?

• Reliability, simplicity, and economy

• Efficiency, speed, and cost-effectiveness

• Selectivity, speed, and sensitivity

• Accuracy, complexity, and cost-effectiveness

What is the main operating principle of electromagnetic attraction relays?

• Electromagnetic interference

• Electromagnetic attraction

• Electromagnetic repulsion

• Electromagnetic induction

What is the purpose of a biased beam relay?

• To compare the current entering and leaving a section of the system

• To measure the voltage and current in a circuit

• To operate as a percentage differential relay

• To balance the voltage in a system

What is the main disadvantage of the voltage balance differential relay system?

• Suitable for protection of cables of relatively short lengths

• Requires a multi-gap transformer construction

• Dependent on the impedance of pilot cables

• Prone to electromagnetic interference

What is the principle of operation of a time-distance impedance relay?

• Operates based on the ratio of applied voltage to current

• Compares the current entering and leaving a section of the system

• Adjusts its operating time according to the distance of the relay from the fault point

• Operates based on the excess of current for its operation

What is the main function of a directional power relay?

• Operates when power flows in a specific direction

• Operates based on the excess of current for its operation

• Compares the current entering and leaving a section of the system

• Measures the voltage and current in a circuit

What is the main function of a definite-distance impedance relay?

• Operates based on the excess of current for its operation

• Compares the current entering and leaving a section of the system

• Adjusts its operating time according to the distance of the relay from the fault point

• Operates instantaneously for fault up to a pre-determined distance from the relay

What is the main function of a current differential relay?

• Compares the current entering and leaving a section of the system

• Operates based on the ratio of applied voltage to current

• Adjusts its operating time according to the distance of the relay from the fault point

• Operates based on the excess of current for its operation

What is the main function of a distance or impedance relay?

• Operates based on the ratio of applied voltage to current

• Compares the current entering and leaving a section of the system

• Adjusts its operating time according to the distance of the relay from the fault point

• Operates based on the excess of current for its operation