The erstwhile Electricity Board which came into existence in 1959 was responsible for the following three main categories of Services in the field of Electricity

(i) Generation

(ii) Transmission and

(iii) Distribution

Under Electricity Sector Reforms agenda, Government of Andhra Pradesh promulgated Electricity Reforms Act,1998.

The erstwhile SEB was unbundled into six entities as a part of reforms process sharing the services in the above three main categories:

(i) Generating Company (GENCO)

(ii) Transmission Company(TRANSCO)

and four Power Distribution Companies viz.

(i) CPDCL

(ii) SPDCL

(iii) NPDCL

(iv)EPDCL

In the above process, TRANSCO came into existence on 1.02.1999 for Transmission of Power across the State of undivided Andhra Pradesh.

However TRANSCO remained as Single buyer in the state, purchasing power from various Generators and selling it to above four DISCOMs in accordance with the Terms and Conditions of the individual PPAs at Bulk Supply Tariff (BST) rates from Feb 1999 to June 2005.  

Subsequently,in accordance with the Third Transfer Scheme notified by GOAP, the undivided TRANSCO ceased to do power trading and has retained powers of controlling system operations of Power Transmission in the voltage levels from 132 KV and above where-as four DISCOMs have become independent in distributing power to various consumers in the voltage levels from 33KV and below.

As per AP Reorganization Act 2014, the then TRANSCO was divided into TSTRANSCO and APTRANSCO. Accordingly TSTRANSCO was established as a Company w.e.f 2-6-2014 for the State of Telangana providing services in the Transmission category.