Prediction and measurement of power line carrier signal attenuation and fluctuation

[摘要] ENGLISH ABSTRACT:A frequency domain Power Line Carrier (PLC) simulation program, with theability to simulate signal attenuation including the coupling equipment, wasdeveloped. This simulation program was put to the test against the independentprogram of Professor L.M. Wedepohl and against practical field measurements.The predictions of the two programs were in precise agreement for a wide range ofinput parameters. Results from the field tests and predictions also showed closeagreement.Further investigations, applying the simulation program, explained how groundconductors and soil resistivity influences PLC signal propagation.An experiment, which was developed to monitor PLC signal attenuation, wasinstalled on the PLC system between Koeberg power station and Acacia substation,both near Cape Town. Data logged continuously over 28 days, indicatedmeasurable and deterministic PLC signal attenuation variations with typical timeconstants of a few hours. Simulations of the PLC system indicated that the signalamplitude variations were influenced by changes in the height above the groundplane of the phase conductor.This significant finding creates the possibility to obtain real time knowledge of thesag of an Over Head Transmission Line (OHTL) by exploiting an operational PLCsystem. The knowledge about real time sag can be used in economical dynamicampacity control systems. The practical and financial benefits to the electricitysupply and distribution industry can be significant.

[发布机构] Stellenbosch University