IEC TR 63042-303 pdf – UHV AC transmission systems – Part 303: Guideline for the measurement of UHV AC transmission line power frequency parameters
This part of lEC 63042 specifies measurement methods of UHV AC transmission line powerfrequency parameters. These measured parameters mainly include sequence parameters,mutual parameters between double-circuit lines，phase parameters and some other relatedparameters.
2 Normative references
The following documents are referred to in the text in such a way that some or all of theircontent constitutes requirements of this document. For dated references，only the editioncited applies. For undated references, the latest edition of the referenced document (including
any amendments) applies.
IEC Guide 115:2007，Application of uncertainty of measurementto conformity assessmentactivities in the electrotechnical sector
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
Is0 and lEC maintain terminological databases for use in standardization at the followingaddresses:
·IEC Electropedia: available at http://www.electropedia.orgl
.Iso Online browsing platform: available at http://www.iso.orgl/obp
offset frequency method
method that can measure the parameter of transmission line by applying a test power sourcewith a frequency offset from the power frequency
terminal of a transmission line,at which a power source is applied for the parametermeasurement
terminal opposite to the source terminal of a transmission line
one-terminal measurement method
measurement method, at which only source terminal is measured
two-terminal synchronous measurement method
measurement method at which both source terminal and ending terminalare measuredsynchronously
type of power frequency parameters， which characterize electric and magnetic couplingcharacteristic for single phase or between two phases，including self-impedance，mutualimpedance, self-capacitance and coupling capacitance
voltage caused by the electromagnetic or electrostatic effect of adjacent energized lines orequipment
electric current resulting from the displacement of charge carriers due to an induced voltage
[SOURCE: IEC 60050-121:2008,121-11-29]
Due to the complication of the geological conditions along the corridor of long distance UHvAC transmission lines，where soil resistivity and transmission tower size vary,it is difficult toobtain accurate transmission line power frequency parameters through theoretical analysisand calculation. To obtain the accurate power frequency parameters, field measurement isnecessary. However，the accuracy of field measurement is influenced by measurementmethods due to the distributed characteristic and electromagnetic coupling of uHV AC lines.Therefore,appropriate measurement methods are importantto obtain accurate powerfrequency parameters. ln this document, different measurement methods are applied toacquire accurate parameters.
4.2 Measurement items
The recommended parameters which need to be measured are as follows:
zero-sequence impedance,zero-sequence capacitance,
mutual impedance and coupling capacitance between double-circuit lines,self-impedance of one phase,
self-capacitance of one phase,
mutual impedance between two phases,coupling capacitance between two phases,-induced voltage and induced current,
.phase verification and insulation resistance,