ZPC overhauls Hwange Power Station unit

THE Zimbabwe Power Company (ZPC) has completed the overhaul of Unit 4 at Hwange Power Station which is now up and running as the company works towards increasing power generation.

Kudzai Kuwaza

ZPC public relations executive Fadzai Chisveto said this week the aim of the overhaul was to increase the efficiency and output of the unit.

“Unit number 4 at Hwange Power Station was taken out on the October 12, 2014 to undergo a planned major overhaul. At the time of the overhaul, the unit had run a total of 37 9993,46 hours and was producing an average of 95 MW,” Chisveto told businessdigest on Wednesday.

“The unit had not produced much beyond 100 MW as it was experiencing high end thrust problems, pin oil pressure saturation problems and also the turbine blades had faults. On the boiler side the unit was running with blistered tubes due to persistent condenser tube leaks, and worn out fans among other challenges.”

Chisveto said the output after the overhaul was increased from 95 to 115 MW.

The major overhaul works were carried out by Alstom Power Services of South Africa as the lead contractor on the turbine and generator, and GEC Zimbabwe as the lead contractor on the boiler side.

The other works included the replacement of electrical boards by ABB, installation of new generator transformer by local company Helcraw, installation of new ID Fan runners by local outfit Technosphere Energy Services, boiler acid cleaning by South African company Gra-Tech and the installation of new extraction pumps by Warman Zimbabwe, Chisveto said.

The outage of the unit took longer than expected mainly because of damages that were found after opening the turbine, which required extensive works to be done in South Africa, she said. The total outage duration was 171 days against a planned 97 days.

Hwange Power Station has a designed capacity to produce 940 MW, but sometimes produces less than half of its potential due to a higher failure rate as a result of the use of aging machines.