Overview and Key Features of +/-320 kV, 2×1000 MW Pugalur-trichur VsC HVdC Link Vardikar M., Singh V., Rao M.S., Bhattacharya S., Mukherjee B.B., Kumar Rakesh Power Grid Corporation of India Limited Online published on 3 September, 2019. Abstract HVDC transmission links are most preferred solution for bulk power transfer over long distances from remote generation to load centres. Raigarh-Pugalur-Trichur HVDC scheme is such upcoming bulk power transmission scheme in India to transmit 6000 MW of power pooled from several generation plants at Raigarh, Western Region to Southern Region. Out of the 6000 MW transmitted power, 4000 MW shall be received at Pugalur, Tamil Nadu while 2000 MW at Trichur, Kerala in Southern Region. To meet above requirements, an LCC HVDC link from Raigarh to Pugalur and a VSC HVDC link from Pugalur to Trichur are under implementation[1]. Pugalur is common converter bus for both the LCC HVDC link (normally operating as inverter) and VSC HVDC link (normally operating as rectifier). This configuration of LCC and VSC HVDC links is unique and limited literature is available for such configuration[3, 4]. It is observed that common Pugalur converter bus is moderately strong (with Short Circuit Ratio of 3.3 for LCC HVDC link in Off-Peak case) and Raigarh-Pugalur HVDC link is of considerable size (15–20%) compared to power demand of Southern Region. Hence, it is vital to maintain stability and study the combined performance of the VSC and LCC HVDC links. Preliminary studies have been carried out for possible performance improvement of LCC HVDC link, recovery of LCC HVDC link for AC network faults and performance of combined scheme for commutation failures, temporary DC line faults[2]. This paper presents overview and features of Pugalur Trichur VSC HVDC link from utility perspective especially for combined performance of VSC and LCC HVDC links. The VSC HVDC scheme operates at ± 320 kV with 2x1000 MW power transmission capacity. The scheme consists of two symmetrical monopoles with half bridge configuration. It is based on Modular Multilevel Converter (MMC) topology. It is designed to transmit 2000 MW power from Pugalur to North Trichur over a distance of 179 km. The transmission scheme is a combination of overhead line (around 147 km) and underground cable (around 32 km). The transition station serves as interface between overhead line and cable. The VSC HVDC link has 2 x(±330) MVAR reactive power capability at full load operation. With no active power transmission, 2 x (±550) MVAR reactive power support is available from VSC HVDC link at both Pugalur and Trichur. The VSC HVDC link has fast acting voltage control through reactive current modulation. It is well known that LCC inverter operation is sensitive to AC bus voltage. Hence it is envisaged presence of VSC HVDC at Pugalur would enhance performance of 6000 MW Raigarh Pugalur HVDC link. The VSC HVDC link will have black start capability. It shall be possible to black start one converter station from other end via the DC line. After start up, the HVDC is able to restore a passive AC system by energizing the AC bus bar. In summary, the paper covers features of VSC HVDC link to have reliable operation and high availability. Top Keywords High Voltage Direct Current (HVDC), Line Commutated Converter (LCC), Voltage Source Converter (VSC), Multi-Infeed HVDC Systems, Commutation Failure. Top |