Transmission and Distribution
The role of Transmission and Distribution (T&D) is to provide safe and reliable electricity supply to Lesotho residents and businesses as a whole. The Transmission network evacuates power from the generation sources namely ‘Muela Hydropower (LHDA), Eskom (South Africa) and EDM (Mozambique) to LEC load centres. The supply from ‘Muela and Eskom plus EDM (at Maseru intake) is transmitted through the 132kV lines to Maputsoe Substation and Mabote Substation respectively. The supply from Eskom (Clarence intake) enters Lesotho through 88kV line at Khukhune Substation in Butha-Buthe, while Qacha’s Nek intake is through 22kV line from Matatiele.
The transmission lines are of voltage levels 132kV, 88kV, 66kV and 33kV. However, there are places where LEC distributes with 33kV like Thabana Morena in Mafeteng. The transmission voltages are stepped down to distribution voltages through 45 substations of which six of them namely Mabote, Mazenod, Maputsoe, Ramarothole, Litsoeneng and Khukhune Substations are critical for the supply of electricity countrywide. Qacha’s Nek and Mokhotlong districts are the only districts that are not connected to the main national grid.
The Distribution network distributes power from substations to electricity users. The Distribution network ranges from the voltage of 11kV up to the customers supply at 220V and 380V. The transmission and distribution network form the LEC core business, without them and its customers, LEC does not exist.
The department performs planned and unplanned network maintenance to keep LEC network assets in an operational status. Planned maintenance is whereby defects are identified through inspections, oil analysis, infrared scanning and other tests and are rectified before failure occurs. Most of critical planned maintenance facing LEC is refurbishment of dilapidated switchgear, 33kV and 11kV worn-out wooden pole structures and upgrading of conductors that are limiting capacity. Another massive preventative maintenance include circuit breakers and other substation equipment tests and assessing and maintaining of transformer on-load tap-changers (OLTC’s) in all the transmission substations. For the past years LEC has maintained availability of supply to more than 99% on the transmission network and to around 95% on the distribution network.
Unplanned maintenance (faults) are dominating planned maintenance. Fault is an emergency power outage caused by many factors including but not limited to ageing network, harsh weather conditions and vandalism of network. In the recent years acts of vandalism have increased in a high rate resulting in engagement of bulk of LEC resources to restore power. There are time-lines set by the Regulator for restoration of faults that LEC has to comply with and LEC is partly complying because of the magnitude of unplanned power outages.
Other departmental roles include testing of installations, surveying, generating quotations and implementing service connections in the nine districts outside Maseru. These activities that relate to customer connection are initiated by customers that come to apply for electricity connection at LEC. There are time-lines set by the Regulator that LEC has to comply with in providing these services.