Did i have to collect service tax from semi-govt

If i am not wrong you are providing service to industrial park for operating and maintaining of electricity. If it is then service tax is applicable provided taxable service value exceeds Rs 10 lac. 

The reason behind this is that entry no. 11 talks about generation & distribution of electricity by an electricity transmission. 

thank you Gagan Deep Singh,

but the situation is i am giving manpower for operation of substation (this substation is a part of distribution of electricity), and giving monthly salary to them . So actual profit will be very less below 10000 , so can i get refund of the same

Your services fall under supply of Manpower. Please remember it does not matter how much actual profit you earned, for service tax applicability if the turnover of taxable services exceeds Rs 10 Lac then you have to pay service tax. You may refer notification no. 33/2012 for more clarity & may take the help of learned person for interpretation.

For valuation of Manpower Service, any amount received for service viz. Salary/Wages, PF/ESI and whatever other amount received from service receiver towards service provided, is required to be added in Value of Service. Also it should be checked/confirmed whether KSEB is business entity registered as body corporate or other wise to ensure partial reverse charge mechanism in terms of N/N 30/2012-ST.