Innovative, Cost Effective Solution for Controlling the Fault Currents in a Large Network – “A Case Study”

The load-generation mismatch in the country has given an impetus to the accelerated growth of power generation by the power planners. Government of India has taken a big initiative by sanctioning development of a large number of Ultra Mega Power Projects with generation capacity of 4000 MW at pit heads or coastal sites. With the encouragement of the government many private players have come up in the field of generation of power and about 173385 MW generation addition by IPP is envisaged by year 2011–12. The accelerated growth of power generation is bringing new challenges for the power system operators. The high density growth of power generation as well as the interconnected operation of the power system is leading to high fault currents in the Indian network. The power equipment in the existing network is rated for a fault current of 40 kA at 400 kV and 220 kV levels. With the growing addition of power generation, there will be many substations in the country where the fault currents shall exceed the rated capability of the existing equipment. Various case studies have been performed using PSS/E and it was found that in 2012 scenario, a number of 400 kV buses as shown in the following sections will have higher fault levels exceeding 40 kA. Similar situation is likely to occur for 220 kV. It may not be economically feasible to replace the existing equipment and hence suitable measures should be adopted for limiting the fault currents. The paper discusses the 2012 scenario where the fault currents will increase by more than 40 kA as per Table 2. There are some ongoing projects in different countries for development of fault current limiting devices.