Why 2 wave traps are provided in the substation?

Answer 1

Line trap also is known as Wave trap. What it does is trapping the high frequency communication signals sent on the line from the remote substation and diverting them to the telecom/teleprotection panel in the substation control room (through coupling capacitor and LMU).

This is relevant in Power Line Carrier Communication (PLCC) systems for communication among various substations without dependence on the telecom company network. The signals are primarily teleprotection signals and in addition, voice and data communication signals.Line trap also is known as Wave trap. What it does is trapping the high frequency communication signals sent on the line from the remote substation and diverting them to the telecom/teleprotection panel in the substation control room (through coupling capacitor and LMU).

This is relevant in Power Line Carrier Communication (PLCC) systems for communication among various substations without dependence on the telecom company network. The signals are primarily teleprotection signals and in addition, voice and data communication signals.

The Line trap offers high impedance to the high frequency communication signals thus obstructs the flow of these signals in to the substation busbars. If there were not to be there, then signal loss is more and communication will be ineffective/probably impossible.

Answer 2

There are multiple reasons for this, depending on the configuration. If the wavetraps are on different lines, they are likely tuned to different carrier frequencies and are used to filter out the carrier for the line they are installed on. If they are installed on the same line, there may be multiple carrier frequencies used, or carrier is applied to multiple phases if on different phases.

Answer 3

for about 60 years there have been high frequency subcarriers in the high voltage wires to open and close breakers remotely from the power plant

usually this is filtered out before reaching the low distribution voltage

in the last 5 or 10 years with the "advanced" electronics every costumers meter is read thru these high freq signals on the distribution voltages i suspect that a lot of the demultiplexing will be done at substations rather than the power plants

I have seen some explanations but they are at that 6th grade newspaper 2nd grade AD level it wasnt clear to me weather its some continous packet or some sort of station poling for every meter with a medium sized city having 100,000 meters or so it probably cant be everyone in the same time slot