For the "slump sale basis" deal, Tata Power has entered into a "binding understanding" with Nelco.
In a regulatory filing, the power utility said the consideration would be around Rs 8.3 crore.
"The UGS business involves supply, installation and servicing of sensors for the Ministry of Defence.
After purchase, the UGS business would be housed in Tata Power's strategic engineering division, which is also a supplier of defence equipment and solutions.
Acquisition of the UGS business will provide synergies to the existing business of Tata Power SED and has scope for growth and expansion, the filing said.
The transfer of the business is subject to approvals and consent of Defence authorities.