Maintenance and Repair of the CWP at the Semarang Combined-Cycle Plant

As part of its commitment to supporting the reliability of power generation systems, Sinar Sakti Matra Nusantara (MATRA) carried out maintenance and repair work on the Circulating Water Pump (CWP) of the combined-cycle plant at PT PLN Indonesia Power UBP Semarang. The work covered inspection, disassembly, repair of the principal components, balancing, and reassembly of the unit, so that the CWP could return to optimal operation.

Scope of Work

The scope opened with work preparation and an incoming inspection, followed by disassembly so that the condition of every principal CWP component could be examined in full. On the strength of the inspection findings, repairs were carried out on several critical components, among them:

• Repair of the CWP shaft, covering run-out inspection, straightening, and roundness verification to restore the alignment of the shaft.
• Repair of the CWP impeller blades through welding, machining, and finishing, to restore both their profile and their hydraulic performance.
• Dynamic balancing of the impeller once repaired, to keep the rotor's mass distribution even and minimise vibration in operation.
• Assembly of all CWP components once every stage of the repair work was complete.

Alongside that principal work, the project also covered on-site loading and unloading, the use of a mobile crane, and the mobilisation and demobilisation of equipment and personnel to the work site.

Precision Repair Work

Every stage of the repair was carried out with an engineering approach that puts dimensional accuracy and quality of workmanship first. The shaft repair involved run-out measurement, roundness checks, straightening, machining, and a re-inspection to confirm the shaft had been returned to its operational specification.

The impeller repair, meanwhile, covered welding on the blade area and the inner diameter (ID), machining to return the component to its design dimensions, and balancing as the final stage before it was refitted. The job documentation also records the condition inspection before repair, the repair work itself, and the condition of the components once the work was finished.

Supporting the Reliability of the Plant's Cooling System

The Circulating Water Pump (CWP) is one of the key items of equipment in a power plant's cooling system. The reliability of this pump keeps the cooling water circulating, which in turn supports the efficiency and the continuity of the plant's operation.

Through a combination of inspection, precision repair, machining, straightening, welding, balancing, and reassembly, MATRA ensures that every component it repairs carries the quality and performance its customers' operations call for. This work is a further demonstration of MATRA's commitment to delivering the maintenance, repair, and engineering services that support the reliability of industrial and power generation assets in Indonesia.