What is the purpose of a line trap?

The purpose of a line trap is to prevent the transmission of high-frequency signals in unwanted directions. In power systems, line traps are employed primarily in conjunction with protective relaying and communication systems, specifically to isolate high-frequency communication signals from the power frequency. This function is essential in ensuring that signal integrity is maintained for communications, such as those used for telemetry or control, while protecting the power system from interference that could degrade performance.

In this context, line traps are often installed on transmission lines to allow lower frequency power signals to pass through while blocking higher frequency signals that could cause disruptions or interference. This selective filtering is crucial for maintaining the stability and reliability of electrical systems, especially when devices like protective relays are transmitting data across the system.

Other options, while they may seem relevant to electrical systems, do not accurately describe the specific function of a line trap. For example, enabling electricity to flow freely does not align with its purpose of selective signal management. Similarly, storing energy or enhancing the capacity of power frequency does not pertain to the primary role a line trap plays in the transmission of signals.