Transmission Development Directorate (TD) is responsible for the development and maintenance of the infrastructure for use for efficient and reliable transportation of electricity from generating stations to bulk supply points and to large mining and industrial customers. The transmission grid is a highway for electricity delivery across the country and also forms part of the regional grid used for power exchange with other countries
The ZESCO transmission grid comprises transmission lines and substations at 330 kV, 220 kV, 132 kV and 66 kV voltage levels. The backbone of the grid is built on a robust 330 kV system from the southern part of the country where the major generating stations are located through Lusaka and Central provinces to the Copperbelt.
Transmission Development Directorate has five technical departments; Transmission North (TN), Transmission South (TS), Transmission Development North (TDN), Transmission Development South (TDS) and Electro technical Services (ETS). Transmission North and South are responsible for ensuring that transmission assets are maintained in a cost effective manner to maximize asset availability. Operations of the network is also the mandate of TN and TS. ETS provides expertise in network protection and control and the infrastructure for local and remote monitoring of substations on the network (SCADA). ETS is also in charge of metering systems for the transmission system.
TDN and TDS are charged with transmission system expansion both in the short and medium term and in the long term. The main focus of the two departments is to determine the timing and type of new facilities required to provide adequately rated transmission network to meet the demands of future generating facilities and load growth. A number of expansion projects are currently in progress.
ZESCO exports excess power particularly during off peak periods to Zimbabwe, South Africa, Namibia, Democratic Republic of Congo (DRC) at high voltage; Botswana, Namibia, Tanzania as well as DRC import at low voltage.