Chapter 4.3 Conductance PDF

Module 4 Chapter 4.3: Conductance All Rights Reserved 1 Conductance • Conductance accounts for real power loss between conductors or between conductors and ground. • For overhead lines, this power loss is due to leakage currents at insulators and to corona. 2 Conductance • Insulator leakage cu...

Module 4 Chapter 4.3: Conductance All Rights Reserved 1 Conductance • Conductance accounts for real power loss between conductors or between conductors and ground. • For overhead lines, this power loss is due to leakage currents at insulators and to corona. 2 Conductance • Insulator leakage current depends on the amount of dirt, salt, and other contaminants that have accumulated on insulators, as well as on meteorological factors, particularly the presence of moisture. • Corona occurs when a high value of electric field strength at a conductor surface causes the air to become electrically ionized and to conduct. • The real power loss due to corona, called corona loss, depends on meteorological conditions, particularly rain, and on conductor surface irregularities. • Losses due to insulator leakage and corona are usually small compared to conductor I2R loss. • Conductance is usually neglected in power system studies because it is a very small component of the shunt admittance. 3