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Temperature rise and DC current capability tests of star-point reactor used in HVDC transmission

Dalibor Filipović-Grčić ; Končar - Electrical Engineering Institute Inc., Zagreb, Croatia
Božidar Filipović-Grčić orcid.org/0000-0002-2230-1336 ; University of Zagreb, Faculty of Electrical Engineering and Computing, Croatia
Igor Žiger ; Končar - Instrument Transformers Inc., Zagreb, Croatia
Danijel Krajtner ; Končar - Instrument Transformers Inc., Zagreb, Croatia
Danijel Brezak ; Končar - Electrical Engineering Institute Inc., Zagreb, Croatia
Rajko Gardijan ; Končar - Electrical Engineering Institute Inc., Zagreb, Croatia

Sažetak

Star-point reactors are grounding devices installed in HVDC stations between the
converter transformer secondary side and AC side of converter arms to provide a reference to
ground. Such reactors are used as high-impedance grounding on the converter side of power
transformers, providing high impedance path for the fundamental harmonic (i.e. 50 or 60 Hz)
and a low impedance path for DC current, eliminating DC current flowing through the
transformer windings. Temperature rise and DC current capability tests of 420 kV star-point
reactor are presented in this paper. The purpose of temperature rise test is to verify that
temperatures that can damage the insulation of star-point reactor will not be reached with the
specified service conditions. The temperature rise test was carried out according to the
requirements of the IEC 61869-3 standard and client’s request which included simultaneous
application of fundamental, 3rd harmonic voltage and DC excitation. The inclusion of 3rd
harmonic excitation of an amplitude up to 15% simulates voltage harmonic distortion which
may appear in the power system at the location of star-point reactor installation. Prior to
temperature rise test, DC current capability test was performed. The goal of this test is to
determine the value of DC current at which the saturation point is reached. DC current is
injected through star-point reactor while AC voltage is applied. Two different cases are
considered regarding AC voltage: test with fundamental voltage harmonic and test with
fundamental voltage harmonic with superimposed third voltage harmonic. Test circuit is
proposed which is suitable for generation of complex voltages composed of fundamental
harmonic and superimposed third harmonic with amplitudes up to 15% of the applied
fundamental harmonic. The proposed test circuit was also used during the temperature rise test
and it is applicable for testing of HV equipment with rated voltage up to 420 kV.

Ključne riječi

Temperature rise test; star-point reactor; DC current capability test; HVDC transmission.

Hrčak ID:

213491

URI

https://hrcak.srce.hr/213491

Datum izdavanja:

1.8.2018.

Posjeta: 1.061 *