Operational experience in 1200 kV national test station (UHVAC), India

POWERGRID in association with Indian manufacturers have established a 1200 kV National Test Station (NTS) at Bina, Madhya Pradesh, India with an objective of developing indigenous Ultra High Voltage AC (UHVAC) equipment and to gain first hand operational experience before full scale commercialization of UHVAC technology in Indian grid. The other objectives of this test station are to facilitate long term performance evaluation and carrying out optimization studies on 1200 kV class equipment. Operational experience gained from NTS is very crucial for finalizing specifications of 1200 kV equipment for the upcoming 1200 kV projects in India.

This paper gives a glimpse on present status of 1200 kV NTS facility and challenges faced during manufacturing, installation, commissioning and operation of the facility. This paper also describes a typical fault experienced in 1200 kV National Test Station (NTS) and its systematic investigation. Immediately, after charging of 1200 kV test station from 400 kV side of 400/1200 kV transformer (three single phase units) a flashover was seen on outer side of tank of one of these transformers and all three single phase units got tripped on over-current. It was initially assumed that there was fault internal to transformer however all test results showed that transformer was in healthy condition. In-depth study was carried out in PSCAD software, to simulate the actual scenario. The results of the simulation study are also discussed in this paper.