Fundamental Frequency Blocking Filters for Champa-Kurukshetra HVDC ±800 kV, 6000 MW HVDC Parallel Bipole Transmission System – Design Consideration Dugar A.1, Óheidhin G2, Kumar A.2 1General Electric, India 2General Electric, United Kingdom Online Published on 13 May, 2022. Abstract This paper presents the design considerations that has been considered while designing or proposing a fundamental frequency DC blocking filter for Champa-Kurukshetra HVDC scheme. The paper details the lessons learnt whilst designing the blocking filter for the Champa-Kurukshetra HVDC link. Champa-Kurukshetra HVDC link is a ±800 kV, 6000 MW parallel bipole HVDC scheme [1]. The DC transmission length in this scheme is approximately 1305 km. In the total span of the DC lines, AC lines often run parallel to the DC line in very close proximity. Therefore, a fundamental frequency blocking filter is designed to limit the induced fundamental current on the DC line. There are various criteria for designing blocking filters, however most important is to limit DC current in the converter transformer. Various detuning factors are used in the designing of blocking filters, which is detailed in this paper. The presence of a blocking filter adds high impedance at fundamental frequency in the DC circuit, which reduces the flow of the fundamental current in the DC circuit for a given induced fundamental voltage. This also changes the resonance profile of the DC system. Therefore, DC system components, especially the DC smoothing reactor, are required to be designed accordingly. In the Champa-Kurukshetra scheme, second harmonic DC filters are used. Therefore, the blocking filter should be designed to mitigate any adverse interaction with low harmonic order DC filters. Also, the blocking filter has an impact on the transient stresses on neutral equipment and surge arresters. Therefore, insulation co ordination requires special attention with the blocking filter and hence, protective levels and energy of surge arresters are to be co-ordinated judiciously. This paper details all the aforementioned points and presents the blocking filter design for Champa-Kurukshetra HVDC link. Top Keywords HVDC, AC-DC Interaction, Blocking Filter, PSCAD. Top |