Typical Disturbances in HVDC Systems

Telephone Line Disturbance

• A typical HVDC system disturbance can occur when frequencies within the range of normal hearing cause audible interference on telephone lines; this normally occurs only in telephone lines which run close to a HVDC converter station. The disturbance is often the cause of improperly grounded telephone lines rather than within the HVDC system itself.

PLC Disturbances

• Another typical disturbance occurs when frequencies from a PLC (power line carrier) communications system interfere with an HVDC system converter. PLC systems are used to carry or piggyback electronic data on HVDC electric delivery networks, and their presence can cause high-frequency noise disturbance.

Radio Signal Interference

• Yet another common frequency-basesd HVDC system disturbance happens when non- or improperly screened HVDC converter stations interfere with nearby radio signals. This most often occurs with AM radio signals and does not typically affect higher frequency, FM stations.

Environmental Disturbance

• Sound pollution in the space surrounding a HVDC converter station is a common disturbance. The sound emanating from power transformers, industrial-strength cooling fans and other systems which help a HVDC converter station function all contribute to ambient noise disturbances in the HVDC system's area.