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Rural Electrification Developments
By 1981 the construction of
small-scale hydro electric
plants was being contemplated.
These were aimed at supplying
electricity to the rural and
remote mountain areas of the
country, and at reducing diesel
generation costs.
This plan was realized in 1988
when a 180kW mini hydro-plant in
Semonkong was commissioned.The
plant is situated along the
Maletsunyane River in the Maseru
district, and supplies about 26
consumers in the Semonkong
development area.
In 1989 a 2 MW
mini hydro plant situated along the Mantsonyane river was
inaugurated. This mini hydro plant in the Thaba-Tseka region is
connected to the National grid and supplies areas such as Roma,
Molimo-Nthuse and Thaba-Tseka at times when the main grid is
inoperative. During normal operation it is utilized for peak
lopping, thus reducing the cost of electricity to LEC.
In 1990 two more
mini hydro plants were commissioned: the Tlokoeng 670 kW plant
situated along the Khubelu river (Mokhotlong) and the Tsoelike 400kW
plant located along the Tsoelike river in Qacha?s Nek. Although the
hydro plants were originally planned to serve the people living in
the rural areas of Lesotho, they have generally been operating at a
very limited scope. The main reason for this is the recurring
drought the country has been experiencing. The acute water shortage
has forced the implementation and use of costly diesel generators.
This has
initiated plans to connect all these areas to the main electricity
grids, in order to reduce the current high costs. Beneficiaries of
these hydro plants are mainly hospitals, clinics, missions,
commercial enterprises and a few domestic house holds.
Major Network Strengthening
In 1984 the company embarked on
a long-term plan of improving
the network system and
furthering the extension of
power to the rural areas. The
11kV circuits which connected
Lesotho to Eskom were upgraded
to 88kV / 33kV which was phased
out in 1991 when the 132kV
system was introduced. As of the
introduction of 132 kV system in
Lesotho, the 132 kV now extends
to the South with the
Ramarothole 132/33 kV
substation, just outside the
Mafeteng town. Further South,
the 132 kV system extends to
Mohale’s Hoek with the 132/33 kV
substation at Litsoeneng in
2006. Whilst this has
facilitated the availability of
reliable supplies to industrial
development in the South, the
network extensions to the rural
areas of Tŝakholo with the 11 kV
network; Ha Makhakhe and
Thabana Morena with 33 kV
network, have made it possible
to extend to the rural areas.
In 1985 three
more 33/11 kV substations were constructed at Mazenod, Roma and St.
Agnes (Teyateyaneng). The Mazenod substation supplies the new
Moshoeshoe I International airport with power.
In 1986
construction of four 33/11 kV substations at Highway, Botsabelo,
Pioneer Road and Mohale’s Hoek started.
The additional 33/11 substations
that have since been developed
include:
1.
Thetsane and Tikoe, that are
both in the Thetsane and Tikoe
areas with major industrial
(textile) development at
Thetsane.
2.
LEC Border 33/11 kV substation
upgrade.
3.
Mafeteng and Quthing
33/11 substations.
Network Control
In 1987 a supervisory control and data acquisition (SCADA) control
system was installed at LEC headquarters, which improved
supervision, and hence speedy detection and rectification of faults.
With the rapid
pace of development of the control technology, the initial SCADA
system is facing the following challenges:
1.
Outdated technology resulting in
the un-availability of spare
parts.
2.
Frequent breakdowns.
3.
Un-reliable network monitoring.
The upgrade of
the SCADA system has since been implemented and the control covers
more substations. This improves the restoration times when some term
duration faults (for example, transients faults) occur on the
network.
Communications
Development
The initial
communications for operating on the network, has been predominantly
power line carrier (PLC-based) communication. The only limitation is
the use of PLC telephones only when one is inside a substation where
PLC exists.
The radio
communication system has been implemented with the major drawback
due to the terrain in Lesotho.
The latest
development is the use of optic fibre means of communication. This
is very reliable and with ample capacity. The other features include
both data and voice transmission from the substations via the remote
terminal units (RTU’s) to the control centre. |
