Project Overview
The pulp and paper industry in Southeast Asia has entered a phase of rapid expansion in recent years. Before 2017, the total paper production capacity in the region was less than 3 million tons per year; by 2025, it has exceeded 10 million tons per year. Countries such as Indonesia and Vietnam, benefiting from their proximity to fiber resources and the continuous growth of packaging demand, are emerging as new growth frontiers in the global paper industry. With this rapid capacity expansion, the need for new pulp and paper production lines and the power capacity upgrade of existing plants has become increasingly urgent.
A large pulp and paper production enterprise in Indonesia is building a new integrated production base, with a substantial total investment. The project includes a pulp mill, a paper mill, a chemical recovery plant, and supporting utility facilities. This production base has extremely high requirements for power supply reliability and power quality. The large equipment on the pulp and paper production lines – such as refiners, paper machines, calendars, and sheeters – are all continuously operating impact loads. The pulp mill and paper mill are dusty and corrosive environments, so electrical equipment must have anti-corrosion and moisture-proof capabilities. Moreover, unplanned power outages on the paper production line would cause serious damage to equipment safety and result in significant economic losses. The customer planned to procure a large quantity of oil-immersed power transformers for the substations and workshop distribution systems throughout the production base.
Solution
To address the actual working conditions and stringent requirements of this paper production base, we provided a comprehensive power supply solution centered on the S11-M series fully sealed oil-immersed power transformers.
Equipment Selection
The S11-M series transformers we supplied are 10kV copper-wound units with a fully sealed corrugated-tank design. This structure completely isolates the internal components from the high concentrations of fibrous dust and humid air found in the pulp and paper workshops. The breather is eliminated, fundamentally preventing failures caused by dust clogging and moisture ingress. The transformer ratings cover multiple capacity levels from several thousand kVA up to tens of thousands of kVA, matching the needs of the various voltage-level substations within the production base.
Technical Parameters
The transformers operate at 50Hz, with a high-voltage side of 10±2×2.5kV equipped with an off-circuit tap changer, a low-voltage side of 0.4kV, and a Dyn11 connection group. The Dyn11 connection effectively suppresses harmonics generated by the large number of variable-frequency drives and rectifiers on the pulp and paper production lines, and it suits the operating requirements of high-power impact loads such as refiners and paper machines. The windings are made of high-purity oxygen-free copper, capable of withstanding frequent start-stop cycles and high short-circuit currents. The cooling method is oil-immersed self-cooling (ONAN).
Corrosion Protection and Environmental Adaptability
The transformer tanks are coated with a heavy-duty anti-corrosion system compliant with ISO 12944 standards, ensuring resistance to the corrosive gases, including sulfides, present in the pulp and paper workshops. In addition, the insulation class and temperature rise limits were optimised to meet the continuous high-load operation typical of the paper industry, ensuring long-term stable performance.
Energy Efficiency
Compared with the obsolete S9-type transformers, the S11-M series reduces no-load losses by more than 30%. For a paper enterprise operating 24 hours a day, this energy-saving effect is particularly significant, substantially lowering long-term electricity costs.
Full-Process Service Support
We provided end-to-end services covering manufacturing, anti-corrosion coating, packaging, sea freight to a major Indonesian port, inland transportation to the project site, installation guidance, and commissioning. Complete English technical documentation was supplied to meet the requirements of the Indonesian National Standard (SNI) and the grid connection regulations of the local utility company, PLN.
Client Feedback
The electrical manager of the paper production enterprise commented that the S11-M series transformers supplied by our company have been operating stably and reliably since commissioning. The fully sealed design has performed excellently in the high-dust, high-humidity, and corrosive gas environment of the paper workshops, with zero equipment failures caused by environmental factors. The low-loss characteristics have continuously reduced the plant’s electricity operating costs, delivering significant energy-saving benefits. At the same time, our one-stop service support – from manufacturing to on-site commissioning – effectively coordinated with the overall project construction schedule. This cooperation has provided a solid power guarantee for the stable start-up and ongoing operation of the production base.
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