Transmission-home
Transmission licensee
transmission Licensee
What is Transmission
The Transmission Licensee (TL) is among the four licensees for the Electricity Supply Corporation of Malawi (ESCOM) Limited. The other licensees for the Corporation are Distribution, System and Market Operator and Single Buyer.
Transmission is mandated to plan, build, maintain and operate the transmission network in Malawi under the Electricity Amended Act 2016. The key objective of the Licensee is to efficiently plan, build, maintain and operate the transmission network for sustainability and reliability of electricity supply to customers.
The transmission network transforms voltage and evacuates power from generation plants to the Distribution network. Transmission network comprises extra-high and high voltage power lines and extra-high and high voltage substations with associated secondary equipment consisting of protection panels which cover the entire country.
Transmission Power Lines
Innovation that excites
The power lines network is operated at high voltage rated at 400kV,132 kV and 66 kV. The total coverage of the network is 2683 KM. The overhead transmission lines comprise 172.65 Km for 400kV,1404.82 km for 132kV,1072.81 km for 66kV and 32.52 km for 33kv as presented in the table below and more details in appendix 1
| Voltage (kV) | Route Length (KM) | No of lines | Percentage |
|---|---|---|---|
| 400 | 172.65 | 1 | 6.44% |
| 132 | 1404.82 | 24 | 52.36% |
| 66 | 1072.81 | 34 | 39.99% |
| 33 | 32.52 | 1 | 1.21% |
| 2683 | 60 |
summary of total route length per voltage rating
The network is run on both wooden poles and steel towers. However, most of the wooden pole lines have outlived their lifespans resulting in frequent planned and forced outages which affect the reliability and availability of the transmission system.
| Cluster | KM | No of Lines | Average life | Percentage |
|---|---|---|---|---|
| 132kV Wood | 460.75 | 6 | 44 | 17.17% |
| 66kV Wood | 586.70 | 13 | 43 | 21.87% |
| 33kV Wood | 32.52 | 1 | 26 | 1.21% |
| Total | 1079.97 | 40.25 | ||
| 400kV Steel | 172.65 | 1 | 6 | 6.44% |
| 132kV Steel | 944.07 | 20 | 35.19% | |
| 66kV Steel | 486.11 | 22 | 31 | 18.12% |
| Total | 1602.83 | 59.75% |
Transmission Substations
The transmission network has a total of 43 substations at 400kV,132kV, and 66 kV voltage rating. These substations are made up of primary and secondary equipment comprising control and protection panels as detailed in appendix 2.
Substations have a total of 80 transformers, composed of 2-400 kV transformers, 24-132kV transformers and 54- 66KV transformers as detailed in appendix 2. Substations also have compensating equipment ranging from reactors to capacitor banks. Rating capacity of reactors at the moment is around 100MVAR at 400kV and the rating capacity of capacitor banks is around 10MVAR at 33kV and 14MVAR at 11kV.
In transmission substations, there are some transformers that have also outlived their lifespan, as they were installed some 40 years ago hence need to be replaced to reduce risk of failure. At the moment, some of the obsolete transformers are being replaced under the JICA-funded Project for the Improvement of Substations in Lilongwe’ transformers and two power transformers at Chichiri Substation.
summary of substations capacity
Based on various voltage rating.
| Voltage level | No of S/S | Total Capacity (MVA) | No of Transformers | Percentage |
|---|---|---|---|---|
| 400kV | 2 | 400 | 2 | 2.5% |
| 132 kV | 14 | 658 | 24 | 30% |
| 66kV | 27 | 732.5 | 54 | 67.5% |
| Total | 43 | 1790.5 | 80 |